Coated seeds, methods and uses thereof

Abstract

The present disclosure relates to a coated seed and seed coating composition comprising algae biomass for plant biostimulation and bioprotection against biotic stresses. The disclosed seed coating composition also comprises at least one binder, optionally in combination with at least one drying agent, at least one microbial inoculum, and / or at least one additive.

Description

D E S C R I P T I O NCOATED SEEDS, METHODS AND USES THEREOFTECHNICAL FIELD

[0001] The present disclosure relates to the fields of agriculture, biotechnology, and environmental science, more specifically to the field of plant biostimulants and bioprotectants, particularly to compositions and uses of seeds coated with algae biomasses for plant biostimulation and bioprotection against biotic stresses.BACKGROUND

[0002] The growing global population, coupled with food supply challenges and environmental degradation, demands enhancing agricultural production while safeguarding the environment and human health. Currently, the most common method of improving seed germination and plant growth and protection is through the use of chemical fertilizers and pesticides. These chemicals are applied to the seeds or plants to provide the necessary nutrients and protect them from pests and diseases. Additionally, seeds are coated with microorganisms, nanomaterials, and polysaccharides, among other materials, aiming at enhancing yields (Sohail et al., 2022).

[0003] Despite the advancements in the seed coating field, there are still several challenges that need to be addressed. Firstly, coating of seeds with chemical fertilizers and pesticides presents environmental and health risks. For instance, chemical fertilizers can lead to soil degradation and environmental pollution, while pesticides can have a negative impact on soil, surface and ground water and air quality as well as harming beneficial insects and other non-target organisms. Secondly, these coatings may not be biodegradable, which can lead to long-term environmental pollution. Therefore, there is a need for more sustainable and efficient solutions that can improve plant growth and protection without causing harm to the environment or human health.

[0004] The use of algae in agriculture dates back centuries, although it has gained more prominence in recent decades with the increasing focus on sustainable farming practices. Historically, algae have been used in various agricultural practices, particularly in coastal-adjacent regions, where their natural abundance was more accessible. Algae-based products offer a promising avenue for enhancing crop productivity while simultaneously boosting disease resistance. Through nutrient enhancement, soil improvement, stress tolerance, and disease prevention, algae have the potential to revolutionize sustainable agricultural practices, providing a natural and effective solution for modern farming challenges (reviewed in Parmar et al., 2023). Products derived from algae, for example, alginates (natural polysaccharide extracted from brown algae), were shown to stimulate early growth of plants, leading tohigher crop yields, when used to coat seeds in addition to macro- and micronutrients (Skrzypczak et al., 2021). In another example, emulsion concentrates of homogenized dried algae enriched with minerals used as wheat seed coating led to increased sprouting (Dmytryk et al., 2015). However, these approaches involve a fair amount of processing of the algae, making the process time consuming. These facts are disclosed in order to illustrate the technical problem addressed by the present disclosure.GENERAL DESCRIPTION

[0005] The present disclosure relates to the field of plant biostimulants and bioprotectants, more specifically to compositions and uses of seed coated with algae biomass for plant biostimulation and bioprotection against biotic stresses.

[0006] The present disclosure relates to a coated seed and to a seed coating composition comprising algae biomasses from species of green algae (Chlorella vulgaris, Tetraselmis chuii and Ulva rigida), red alga (Gracilaria sp.), brown algae (Tisochrysis lutea, Skeletonema sp. and Thalassiosira pseudonana); and cyanobacteria (Arthrospira platensis) that were proven to be surprisingly efficacious when used at minimal amounts to coat seeds, as plant biostimulants whilst also endowed with the capacity to increase plant protection against biotic stresses, specifically soilborne pathogens.

[0007] By enhancing crop yields and promoting healthier plant growth, the disclosed coated seeds and coating composition contribute to global food security. Moreover, the environmental benefits of using algae biomass align with the growing emphasis on sustainable agricultural practices, making this technology highly attractive to environmentally conscious farmers, consumers and seed businesses.

[0008] The composition and coated seeds of the present disclosure can be applied across different fields as agriculture, environmental science, circular economy and renewable resources, and even health industry due to reduced use of chemical fertilizers and pesticides.

[0009] In an embodiment, the coated seeds described herein involve minimal processing (essentially drying and pulverization) decreasing the cost, time and environmental impact, on the contrary to the examples described in the state of the art, which involve a fair amount of processing of the algae.

[0010] Surprisingly, the minimal quantities of the algae biomass needed to coat seeds and the two-in-one sowing and biostimulation / bioprotection application shows that the coated seeds of present disclosure provide an easier and cost-effective method to enhance yield both by promoting growth as well as protecting plants from biotic stress. Indeed, the disclosed surface coating composition maintains its functional properties for approximately three months after application, without noticeable degradation of the algal biomass or microbial inoculum. The disclosed coated seed with the surface coating composition retain their beneficial effects even under hydric stress conditions, as evidenced bywheat plants showing enhanced biomass accumulation and improved physiological parameters compared to uncoated controls. This stability supports long-term storage and practical agricultural use.

[0011] In an embodiment, due to the minimal amount of algae biomass used in the seed coating composition of the present disclosure to obtain the coated seeds, in reduction and or substitution of the standard drying agents, the seed coating composition of the present disclosure barely reduces the total number of seeds per kilogram and does not impact on automated seed sowing systems.

[0012] In an embodiment, the coated seeds and the seed coating composition with algae biomass may be used as a plant biostimulant.

[0013] As used herein, the term "biostimulant" refers to a composition which, when applied to seeds, stimulates natural physiological processes of the plant, independently of its nutrient content, thereby improving one or more of nutrient use efficiency, tolerance to abiotic stress, growth, development, yield, and / or quality of the plant or plant-derived products. A biostimulant does not act primarily by supplying essential nutrients or by exerting pesticidal activity, but rather by enhancing the plant's intrinsic metabolic or regulatory mechanisms.

[0014] In an embodiment for better results, the disclosed seed coating composition with algae biomass may be used as a biostimulant for forage plants. Examples of forage plants include but are not limited to legumes and grasses. Thus, seeds of forage and cereal plants can be coated with the disclosed composition to obtain coated seeds.

[0015] In an embodiment for better results, the legume plant is a clover plant, or an alfalfa.

[0016] In an embodiment for better results, the grass plant is a ryegrass plant.

[0017] In an embodiment for better results, the cereal is a wheat plant.

[0018] In another embodiment, the disclosed seed coating composition with algae biomass may be used to increase plant protection against biotic stresses. Biotic stress is the adverse effect of any biotic factor on a plant, negatively impacting plant growth and development. Examples of biotic stresses include but are not limited to attack by bacteria, viruses, fungi and insects. Indeed, plants obtained from coated seeds show higher resistance to biotic stress.

[0019] Another aspect of the present disclosure relates to seed coating composition and method for seed coating with algae biomass comprising an effective amount of algae biomass as described in the present disclosure.

[0020] In an embodiment for better results, the composition may further comprise agriculturally acceptable additives, including, but not limited to, other biostimulants, nutrients, fertilisers, vitamins, minerals, or combinations thereof.

[0021] It is also described a method for plant biostimulation and increasing plant protection against biotic stresses comprising the seed coating composition with algae biomass as described in the present disclosure.

[0022] The term "Nominal coating load" whenever used in this document is indicated to the theoretical or target coating amount selected for application to seeds, expressed as an amount of coating per unit mass of seeds, or per unit seed surface area, and used to define the coating process independently of the coating actually achieved. The actual coating load may differ from the nominal coating load due to process variability, seed heterogeneity, or coating losses during application. Percentages of nominal coating load refer to the proportion of the target coating mass relative to uncoated seed mass, and not to the final weight of the coated seeds.

[0023] The present disclosure relates to a coated seed comprising a surface coating, wherein the surface coating comprises:an algae biomass obtained from at least one algae selected from macroalgae, microalgae or cyanobacteria;a polymeric binder, selected from natural binders, synthetic binders, semi-synthetic binders, or combinations thereof;optionally, a microbial inoculum, selected from a list consisting of bacteria, fungi, yeasts, actinomycetes, cyanobacteria or mixtures thereof.

[0024] In an embodiment, the polymeric binder forms a continuous or semi-continuous matrix of the surface coating.

[0025] In an embodiment, the biomass and / or the microbial inoculum are embedded in the polymeric matrix.

[0026] In an embodiment, the surface coating covers at least part of the external surface of the seed.

[0027] In an embodiment, the surface coating comprises 35 to 85% (w / w) of the algae biomass, preferably 40 to 80% (w / w). Percentage relative to the total mass of the surface coating.

[0028] In an embodiment, the algae biomass is from at least one alga selected from a list consisting of: green algae, red alga, brown algae, cyanobacteria, or mixtures thereof.

[0029] In an embodiment, the green alga is selected from Chlorella vulgaris, Tetraselmis chuii or Ulva rigida; the red alga is selected from Gracilaria sp; the brown alga is selected from Tisochrysis lutea, Skeletonema sp or Thalassiosira pseudonana; the cyanobacteria is selected from Arthrospira platensis.

[0030] In an embodiment, the microbial inoculum comprises microorganisms from the families: Rhizobiaceae, Bradyrhizobiaceae, Azotobacteraceae , or Pseudomonadaceae; preferably Rhizobiaceae or Bradyrhizobiaceae; more preferably Rhizobiaceae.

[0031] In a preferred embodiment, the microbial inoculum comprises microorganisms selected from the species: Rhizobium leguminosarum, Rhizobium etli, Rhizobium phaseoli, Rhizobium tropici; preferably Rhizobium leguminosarum or Rhizobium etli; more preferably Rhizobium leguminosarum.

[0032] In an embodiment, the surface coating comprises 1 to 3% (w / w) of the microbial inoculum, preferably 2.4 to 2.8% (w / w). Percentage relative to the total mass of the surface coating.

[0033] In an embodiment, the polymeric binder is selected from a list consisting of Arabic gum, guar gum, xanthan gum, starch, alginate, cellulose derivatives, polyvinyl alcohol, polyvinylpyrrolidone, polyethylene glycol, acrylic polymers, carboxymethyl cellulose, hydroxypropyl methylcellulose, ethyl cellulose and mixtures thereof.

[0034] In an embodiment, the surface coating comprises 12-30% (w / w) of the polymeric binder, preferably 15-20% (w / w). Percentage relative to the total mass of the surface coating.

[0035] In an embodiment, the surface coating further comprises at least one drying agent, preferably 30 to 40% (w / w) of the at least one drying agent. Percentage relative to the total mass of the surface coating.

[0036] In an embodiment, the drying agent is an inorganic drying agent, organic drying agent, polymeric drying agent, or combinations thereof.

[0037] In a preferred embodiment, the drying agent is selected from a list consisting of: limestone, calcium carbonate, dolomite, gypsum, perlite, bentonite, talc, kaolin, diatomaceous earth, silica, starch, cellulose, lignin, chitosan, polyacrylate polymers, polyvinyl alcohol, polyethylene glycol and mixtures thereof.

[0038] In an embodiment, the surface coating further comprises additives selected from a list comprising biostimulants, nutrients, fertilisers, vitamins, minerals, growth promoters, wetting agents, solvents, buffers, stabilisers, osmoprotectants, solar protectants, excipients, surfactants, emulsifiers, preservatives, essential oils, microorganisms or mixtures thereof.

[0039] In an embodiment, the algae biomass is a dried powder or a paste, preferably a powder.

[0040] In an embodiment, the seed is of a plant belonging to the families: Poaceae, Fabaceae, Brassicaceae, and Solanaceae; preferably Poaceae or Fabaceae.

[0041] In an embodiment, the seed is from wheat, oat, barley, ryegrass, millet, clover, beans, soybean, peas, chickpeas, alfalfa, or fenugreek; preferably wheat, ryegrass, clover, or alfalfa.

[0042] An aspect of the present disclosure relates to a kit comprising the disclosed coated seed.

[0043] A kit for obtaining the disclosed coated seed comprising a biomass from at least one alga, and a polymeric binder, optionally a microbial inoculum and / or a drying agent is also disclosed.

[0044] The present disclosure also relates to a seed coating composition to obtain the disclosed coated seed comprising:35 to 85% (w / w) of algae biomass obtained from macroalgae, microalgae or cyanobacteria, or mixtures thereof; and12 to 30% (w / w) of a polymeric binder selected from natural binders, synthetic binders, semisynthetic binders, or combinations thereof; andoptionally, at least 1 to 3% (w / w) of microbial inoculum selected from a list consisting of bacteria, fungi, yeasts, actinomycetes, cyanobacteria or mixtures thereof.

[0045] In an embodiment, the seed coating composition is a powder, a granulate, a slurry, a film forming formulation, a wettable powder, a sprayable formulation, a suspension concentrate, an emulsion, or an aqueous solution.

[0046] In an embodiment, the composition further comprises at least one drying agent, preferably 30 to 40% (w / w) of the at least one drying agent, more preferably 35% (w / w) of the at least one drying agent.

[0047] In an embodiment, the drying agent is selected from a list consisting of: limestone, calcium carbonate, dolomite, gypsum, perlite, bentonite, talc, kaolin, diatomaceous earth, silica, starch, cellulose, lignin, chitosan, polyacrylate polymers, polyvinyl alcohol, polyethylene glycol and mixtures thereof.

[0048] In an embodiment, the retention of the coating composition on seeds ranges from 45-100%; preferably 60-100%; more preferably 70-100%.

[0049] An aspect of the present disclosure relates to the use of the seed coating composition as a plant biostimulant composition, a plant protector composition, a fertilizer composition, an insecticide composition, a pesticide composition, or a film-coating composition.

[0050] The present disclosure also relates to a method for obtaining the disclosed coated seed, from the coating composition, the method comprising the following steps:adding dropwise a polymeric binder to the seeds, preferably in an amount of 100-200 pL per 5 g of seeds;manual mixing or shaking for up to 10 minutes the mixture obtained in the previous step; adding an algae biomass to the seeds obtained from the previous step, preferably wherein the weight ratio between the biomass and the seeds ranges from 1:20 to 10:20, preferably 2:20 to 3:20; and mixing or shaking the obtained seeds for up to 5 minutes to obtain the coated seeds.

[0051] In an embodiment, the method further comprises a step of mixing the seeds with a microbial inoculum in a ratio of 20 mg per 5 g of seeds before adding the polymeric binder.

[0052] In an embodiment, the method further comprises a step of adding a drying agent, preferably 100 to 500 mg of drying agent per 5 g of seeds.BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The following figures provide preferred embodiments for illustrating the disclosure and should not be seen as limiting the scope of invention.

[0054] Figure 1: Representation of an embodiment of clover (A), alfalfa (B) and ryegrass (C) seeds coated with compositions comprising different algae biomass powders (Cvl, Chlorella vulgaris 1; Cv3, Chlorella vulgaris 3; CvlCv3, Chlorella vulgaris 1 and Chlorella vulgaris 3; Ur, Ulva rigida; G, Gracilaria sp; S, Skeletonema sp; Tc, Tetraselmis chuii; Cv2, Chlorella vulgaris 2; Tl, Tisochrysis lutea; UrCv2TI, Ulva rigida, Chlorella vulgaris 2 and Tisochrysis lutea).

[0055] Figure 2: Representation of an embodiment of clover plants four weeks after germination in controlled conditions.

[0056] Figure 3: Representation of an embodiment of ryegrass plants four weeks after germination in controlled conditions.

[0057] Figure 4: Representation of an embodiment of the photosynthetic quantum yield (Qy) of clover plants germinated from seeds coated with different algae biomasses at four weeks, normalized by the control tested in controlled conditions (Cvl, Chlorella vulgaris 1; Ur, Ulva rigida; G, Gracilaria sp; Cv2, Chlorella vulgaris 2; S, Skeletonema sp).

[0058] Figure 5: Representation of an embodiment of the photosynthetic quantum yield (Qy) of ryegrass plants germinated from seeds coated with different algae biomasses at four weeks, normalized by the control tested in controlled conditions (Tc, Tetraselmis chuii; Cv2, Chlorella vulgaris 2; Tl, Tisochrysis lutea; Tp, Thalassiosira pseudonana).

[0059] Figure 6: Representation of an embodiment of the Chlorophyll Content Index (CCI) quantification of clover plants germinated from seeds coated with different algae biomasses (Cvl, Chlorella vulgaris 1; Cv3, Chlorella vulgaris 3; UrCv2TI, Ulva rigida, Chlorella vulgaris 2 and Tisochrysis lutea) tested in open-air tunnel, field like conditions.

[0060] Figure 7: Representation of an embodiment of the Soil Plant Analysis Development (SPAD) quantification of clover plants germinated from seeds coated with different algae biomasses (Cvl, Chlorella vulgaris 1; Cv3, Chlorella vulgaris 3; UrCv2TI, Ulva rigida, Chlorella vulgaris 2 and Tisochrysis lutea) tested in open-air tunnel, field like conditions.

[0061] Figure 8: Representation of an embodiment of the Chlorophyll Content Index (CCI) quantification of alfalfa plants germinated from seeds coated with algae biomass (CvlCv3, Chlorella vulgaris 1 and Chlorella vulgaris 3) tested in open-air tunnel, field like conditions.

[0062] Figure 9: Representation of an embodiment of the Soil Plant Analysis Development (SPAD) quantification of alfalfa plants germinated from seeds coated with different algae biomasses (Chlorella vulgaris 1 and Chlorella vulgaris 3) tested in open-air tunnel, field like conditions.

[0063] Figure 10: Representation of an embodiment of flavonoids quantification of clover plants germinated from seeds coated with different algae biomasses (Cvl, Chlorella vulgaris 1; Cv3, Chlorella vulgaris 3; CvlCv3, Chlorella vulgaris 1 and Chlorella vulgaris 3; UrCv2TI, Ulva rigida, Chlorella vulgaris 2 and Tisochrysis lutea) tested in open-air tunnel, field like conditions.

[0064] Figure 11: Representation of an embodiment of flavonoids quantification of alfalfa plants germinated from seeds coated with different algae biomasses (Cvl, Chlorella vulgaris 1; Cv3, Chlorella vulgaris 3; CvlCv3, Chlorella vulgaris 1 and Chlorella vulgaris 3; UrCv2TI, Ulva rigida, Chlorella vulgaris 2 and Tisochrysis lutea) tested in open-air tunnel, field like conditions.

[0065] Figure 12: Representation of an embodiment of the Chlorophyll Content Index (CCI) quantification of ryegrass plants germinated from seeds coated with different algae biomasses (Tl, Tisochrysis lutea; UrCv2TI, Ulva rigida, Chlorella vulgaris 2 and Tisochrysis lutea) tested in open-air tunnel, field like conditions.

[0066] Figure 13: Representation of an embodiment of the Soil Plant Analysis Development (SPAD) quantification of ryegrass plants germinated from seeds coated with different algae biomasses (Tl, Tisochrysis lutea; UrCv2TI, Ulva rigida, Chlorella vulgaris 2 and Tisochrysis lutea) tested in open-air tunnel, field like conditions.

[0067] Figure 14: Representation of an embodiment of the growth and development of plants germinated from clover seeds coated with different algae biomasses demonstrated by the shoot dry weight and Leaf Area Index (LAI), normalized by the control tested in controlled conditions (Cvl, Chlorella vulgaris 1; G, Gracilaria sp; Cv2, Chlorella vulgaris 2; Tl, Tisochrysis lutea;S, Skeletonema sp).

[0068] Figure 15: Representation of an embodiment of the growth and development of plants germinated from ryegrass seeds coated with different algae biomasses demonstrated by the shoot dry weight and number of tillers, normalized by the control tested in controlled conditions (Tc, Tetraselmis chuii; Cv2, Chlorella vulgaris 2; Tl, Tisochrysis lutea; Cv3, Chlorella vulgaris 3; Tp, Thalassiosira pseudonana).

[0069] Figure 16: Representation of an embodiment of the total shoot dry matter production from two growth cycles for clover plants established from coated seeds with different algae biomasses (Cv3, Chlorella vulgaris 3; CvlCv3, Chlorella vulgaris 1 and Chlorella vulgaris 3; UrCv2TI, Ulva rigida, Chlorella vulgaris 2 and Tisochrysis lutea) tested in open-air tunnel, field like conditions.

[0070] Figure 17: Representation of an embodiment of the dry biomass yield (two cuts) from algal-coated clover seeds (Cv3, Chlorella vulgaris 3; CvlCv3, Chlorella vulgaris 1 and Chlorella vulgaris 3; UrCv2TI, Ulva rigida, Chlorella vulgaris 2 and Tisochrysis lutea) compared to the untreated control, tested in open-air tunnel, field like conditions and expressed as a percentage increase.

[0071] Figure 18: Representation of an embodiment of the total shoot dry matter production from two growth cycles for alfalfa plants established from coated seeds with algae biomass (Cvl, Chlorella vulgaris 1) tested in open-air tunnel, field like conditions.

[0072] Figure 19: Representation of an embodiment of the dry biomass yield (two cuts) from algal-coated alfalfa seeds (Cvl, Chlorella vulgaris 1) compared to the untreated control, tested in open-air tunnel, field like conditions and expressed as a percentage increase.

[0073] Figure 20: Representation of an embodiment of the total shoot dry matter production from two growth cycles for ryegrass plants established from coated seeds with different algae biomasses (Tc, Tetraselmis chuii; Cv2, Chlorella vulgaris 2; Tl, Tisochrysis lutea; UrCv2TI, Ulva rigida, Chlorella vulgaris 2 and Tisochrysis lutea) tested in open-air tunnel, field like conditions.

[0074] Figure 21: Representation of an embodiment of the dry biomass yield (two cuts) from algal-coated ryegrass seeds (Tc, Tetraselmis chuii; Cv2, Chlorella vulgaris 2; Tl, Tisochrysis lutea; UrCv2TI, Ulva rigida, Chlorella vulgaris 2 and Tisochrysis lutea) compared to the untreated control, tested in open-air tunnel, field like conditions and expressed as a percentage increase.

[0075] Figure 22: Representation of an embodiment of the number of root nodules of clover plants germinated from seeds coated with different algae biomasses at four weeks, normalized by the control tested in control conditions (Ur, Ulva rigida; G, Gracilaria sp; Cv2, Chlorella vulgaris 2; Tl, Tisochrysis lutea; Cv3, Chlorella vulgaris 3).

[0076] Figure 23: Visual evidence of improved nodulation from algal seed coating tested in open-air tunnel, field like conditions. (A) Nodulation in control plants. (B) Close-up of nodules from (A). (C) Promoted nodulation in plants from seeds coated with Chlorella vulgaris 3 (Cv3). (D) Close-up view of the enhanced nodule density and development in (C). Scale bar =5 cm.

[0077] Figure 24: Representation of an embodiment of the phenotypic comparison in controlled conditions of wheat plants grown from seeds coated with algae biomasses. Treatments: Tetraselmis chuii (Tc), Gracilaria sp. (G), and a mix (TcG), under hydric stress (Hs) and non-stress conditions (control). Plants are shown relative to the uncoated control.

[0078] Figure 25: Representation of an embodiment of the total shoot dry matter production of wheat plants grown from seeds coated with different algae biomasses, normalized to the uncoated control incontrolled conditions. Treatments include Tetraselmis chuii (Tc), Gracilaria sp. (G), and their mix (TcG), under both hydric stress (Hs) and non-stress conditions.

[0079] Figure 26: Representation of an embodiment of clover plants three weeks after transplant into substrate inoculated with Pythium ultimum in controlled conditions.

[0080] Figure 27: Representation of an embodiment of the disease index reported as the Area Under the Curve (AUC) of clover plants challenged by Pythium ultimum when compared to Control (not infected) in controlled conditions

[0081] Figure 28: (A) Representation of an embodiment of three-week-old plants grown from seeds coated with algae biomass (Ap, Spirulina platensis) or control, challenged with P. ultimum in controlled conditions. Scale bar = 5 cm. (B) Representation of a quantitative disease assessment showing the disease index as Area Under the Curve (AUC), final disease severity (%), and Log2 Fold Change (Log2FC; grey shaded area) relative to the non-infected control.

[0082] Figure 29: (A) Representation of an embodiment of three-week-old plants grown from seeds coated with algae biomass (Cv2, Chlorella vulgaris 2) or control, challenged with P. ultimum in controlled conditions. Scale bar = 5 cm. (B) Representation of a quantitative disease assessment showing the disease index as Area Under the Curve (AUC), final disease severity (%), and Log2 Fold Change (Log2FC; grey shaded area) relative to the non-infected control.

[0083] Figure 30: (A) Representation of an embodiment of three-week-old plants grown from seeds coated with algae biomass (S, Skeletonema sp.) or control, challenged with P. ultimum in controlled conditions. Scale bar = 5 cm. (B) Representation of a quantitative disease assessment showing the disease index as Area Under the Curve (AUC), final disease severity (%), and Log2 Fold Change (Log2FC; grey shaded area) relative to the non-infected control.DETAILED DESCRIPTION

[0084] The present disclosure relates to a coated seed comprising a surface coating composition, said composition comprising algae biomass for plant biostimulation and bioprotection against biotic stresses. The disclosed seed coating composition with algae biomass may be used as a plant biostimulant.

[0085] In another embodiment, the disclosed seed coating composition with algae biomass may be used to increase plant protection against biotic stresses, namely oomycetes. Examples of oomycetes include but are not limited to Pythium sp.

[0086] In an embodiment, seeds of any species of plant can be treated with the disclosed algae biomass composition, thus resulting in a coated seed.

[0087] In an embodiment, the algae biomass may be in the form of a dried powder or paste.

[0088] In an embodiment for better results, the seed coating composition with algae biomass may be used as a biostimulant for forages, including legumes, grasses, and cereals. Examples of legumes and grasses include but are not limited to clover, alfalfa and ryegrass. Whereas examples of cereals include but are not limited to wheat.

[0089] In an embodiment, the disclosed composition can optionally comprise at least one microbial inoculum and at least one binder (adhesive agent), optionally in combination with at least one drying agent. In a preferred embodiment, the seed coating composition comprises a microbial inoculum, an adhesive agent and a drying agent.

[0090] In another embodiment, the disclosed composition may contain other elements which serve to i) allow the algae biomass and the microbial inoculum to adhere to the seed and ii) allow application in the field using contemporary agricultural equipment. Other agriculturally acceptable additives may be added to the composition. Such agriculturally acceptable additives can include, but are not restricted to, plant growth promoters, nutrients, wetting agents, solvents, buffers, stabilisers, osmoprotectants, solar protectants, excipients, surfactants, fertilisers, emulsifiers, vitamins, minerals, additives and / or preservatives and so on.

[0091] In a further embodiment, to improve efficacy, onset and duration of action, the disclosed composition may further comprise at least one other plant biostimulant and / or bioprotectant, selected from a list comprising essential oils, beneficial microorganisms, extracts from microorganisms or other natural, semi-synthetic or synthetic biodegradable and non-toxic biomolecules.

[0092] In an embodiment, the composition further comprises at least one polymer.

[0093] In a preferred embodiment, the quantity of algae biomass in the seed coating composition of the present disclosure is within an effective range sufficient to achieve uniform seed coverage and enhanced plant performance. Preferably, the algae biomass is applied at a nominal coating load of 50% to 100% relative to the weight of the seeds, wherein for the 50% coating, a drying agent (e.g., talc, graphite, or limestone) is added in an amount equal to the algae biomass so that the total coating weight corresponds to the 100% nominal load. In another embodiment, the algae biomass may comprise one or more algae species.

[0094] In an embodiment, the disclosed coating composition is compatible with previous treatments applied to the seed, such as seed priming.

[0095] A method for plant biostimulation and increasing plant protection against biotic stresses by coating seeds with the algae biomass coating composition is also described in the present disclosure.

[0096] In terms of market demand, there is a growing interest in natural and organic products, including those used in agriculture. The use of the composition of the present disclosure, which is derived fromnatural sources, meets this demand. Furthermore, as populations become aware of the potential health benefits of algae (Wu et al., 2023), there is likely to be an increased demand for products containing algae. Moreover, the use of improved seeds, coated with readily available natural algae biomasses, offers significant economic advantages by reducing sowing costs, enhancing crop yields, and maximizing return on investment for farmers.

[0097] In an embodiment, the disclosed seed coating composition comprises algae biomass selected from macroalgae, microalgae, cyanobacteria, or combinations thereof; preferably macroalgae, microalgae, and cyanobacteria; more preferably macroalgae and microalgae; even more preferably microalgae.

[0098] In an embodiment, the algae biomass derives from algae belonging to the Chlorophyceae, Ulvaceae, Gracilariaceae, Chrysophyceae, Bacillariophyceae, or Cyanophyceae; preferably Chlorophyceae, Ulvaceae, Gracilariaceae, or Chrysophyceae; more preferably Chlorophyceae, Ulvaceae, or Gracilariaceae; even more preferably Chlorophyceae and Gracilariaceae.

[0099] In an embodiment, the algae biomass is obtained from algae of a genus selected from a list consisting of Chlorella, Tetraselmis, Ulva, Gracilaria, Tisochrysis, Skeletonema, Thalassiosira, Arthrospira; preferably Chlorella, Tetraselmis, Ulva, Gracilaria, or Tisochrysis; preferably Chlorella, Tetraselmis, Ulva, or Gracilaria; even more preferably Chlorella, Tetraselmis, and Gracilaria.

[0100] In an embodiment, the algae biomass comprises algae selected from the species Chlorella vulgaris, Tetraselmis chuii, Ulva rigida, Gracilaria sp., Tisochrysis lutea, Skeletonema sp., Thalassiosira pseudonana, or Arthrospira platensis; preferably Chlorella vulgaris, Tetraselmis chuii, Ulva rigida, Gracilaria sp., or Tisochrysis lutea; more preferably Chlorella vulgaris, Tetraselmis chuii, Ulva rigida, or Gracilaria sp.; even more preferably Chlorella vulgaris, Tetraselmis chuii, and Gracilaria sp.

[0101] In an embodiment, the seed coating composition further comprises a microbial inoculum selected from bacteria, fungi, yeasts, actinomycetes, cyanobacteria, or combinations thereof; preferably bacteria and actinomycetes; more preferably bacteria; even more preferably nitrogen-fixing bacteria.

[0102] As used herein, the term "microbial inoculum" refers to a preparation comprising viable microorganisms intentionally introduced into a medium, substrate, or system in order to initiate, promote, or control a biological process. The microbial inoculum may comprise one or more strains or species of microorganisms, such as bacteria, fungi, yeasts, actinomycetes, cyanobacteria, or combinations thereof, in an active, dormant, or reactivatable state, and may be provided in solid, liquid, or semi-solid form. The inoculum can optionally include carriers, nutrients, stabilizers, or protective agents that support microbial viability, stability, or activity prior to and / or after application.

[0103] In an embodiment, the microbial inoculum of the disclosed seed coating composition comprises microorganisms selected from the families: Rhizobiaceae, Bradyrhizobiaceae, Azotobacteraceae , orPseudomonadaceae; preferably Rhizobiaceae or Bradyrhizobiaceae; more preferably Rhizobiaceae; even more preferably Rhizobiaceae of symbiotic nitrogen-fixing bacteria.

[0104] In an embodiment, the microbial inoculum of the disclosed seed coating composition comprises microorganisms of a genus selected from a list consisting of Rhizobium, Bradyrhizobium, Sinorhizobium, Mesorhizobium; preferably Rhizobium or Bradyrhizobium; more preferably Rhizobium; even more preferably Rhizobium sp.

[0105] In an embodiment, the microbial inoculum of the disclosed seed coating composition comprises microorganisms selected from the species: Rhizobium leguminosarum, Rhizobium etli, Rhizobium phaseoli, Rhizobium tropici; preferably Rhizobium leguminosarum or Rhizobium etli; more preferably Rhizobium leguminosarum; even more preferably a strain of Rhizobium leguminosarum.

[0106] In an embodiment, the seed coating composition comprises at least one polymeric binder selected from natural binders, synthetic binders, semi-synthetic binders, or combinations thereof.

[0107] In an embodiment, the at least one binder is a natural binder selected from a list consisting of Arabic gum, guar gum, xanthan gum, starch, alginate, and cellulose derivatives.

[0108] In an embodiment, the at least one binder is a synthetic binder selected from a list consisting of polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polyethylene glycol (PEG), and acrylic polymers.

[0109] In an embodiment, the at least one binder is a semi-synthetic binder selected from a list consisting of carboxymethyl cellulose (CMC), hydroxypropyl methylcellulose (HPMC), and ethyl cellulose.

[0110] In an embodiment, the seed coating composition further comprises optionally at least one drying agent selected from inorganic drying agents, organic drying agents, polymeric drying agents, or combinations thereof.

[0111] In an embodiment, the at least one drying agent is an inorganic drying agent selected from a list consisting of limestone, calcium carbonate, talc, kaolin, diatomaceous earth, and silica.

[0112] In an embodiment, the at least one drying agent is an organic drying agent selected from a list consisting of starch, cellulose, lignin, and chitosan.

[0113] In an embodiment, the at least one drying agent is a polymeric drying agent selected from a list consisting of polyacrylate polymers, polyvinyl alcohol, and polyethylene glycol.

[0114] In an embodiment, the seed coating composition further comprises at least one additive selected from nutrients, micronutrients, stabilisers, preservatives, antioxidants, pH regulators, surfactants, or mixtures thereof; preferably limestone, calcium carbonate, calcium oxide, calcium hydroxide, and magnesium carbonate; and wherein the soil pH-regulating agent may optionally also function as a drying agent during seed coating.

[0115] In an embodiment, the seed coating composition may be provided in the form of a powder, a wettable powder, a sprayable formulation, a suspension concentrate, an emulsion, an aqueous solution, a granulate, a slurry, a suspension, or a film-forming formulation; preferably powder, wettable powder; more preferably extremely fine powder, wettable powder; even more preferably extremely fine powdered biomass.

[0116] In an embodiment, the disclosed seed coating composition may be applied to seeds of cereals, legumes, oilseeds, vegetables, fruits, or industrial crops; preferably cereals, legumes and vegetables; preferably cereals and legumes; even more preferably clover, alfalfa, wheat, maize, or ryegrass.

[0117] In an embodiment, the seed coating composition may be applied to seeds of plants belonging to the families: Poaceae, Fabaceae, Brassicaceae, or Solanaceae; preferably Poaceae or Fabaceae; more preferably Poaceae or Fabaceae, including triticale, wheat, oat, barley, ryegrass, millet, clover, beans, soybean, peas, chickpeas, alfalfa, aor fenugreek; even more preferably wheat, ryegrass, clover, or alfalfa.

[0118] In an embodiment, the seed coating composition may be applied to seeds of plants belonging to a genus selected from a list consisting of: Trifolium, Medicago, Lolium, Triticum, Festuca, Dactylis, Poa, Secale, or Avena; preferably Trifolium, Medicago, Lolium, Triticum, Festuca, or Dactylis; more preferably Trifolium, Medicago, Lolium, Triticum or Festuca; even more preferably Trifolium, Medicago, Lolium, or Triticum.

[0119] In an embodiment, the seeds may belong to plant species selected from Trifolium sp., Medicago sativa, Triticum sp., Lolium sp., Festuca arundinacea, Dactylis glomerata, Poa pratensis, and Secale cereale; preferably Trifolium sp., Medicago sativa, Triticum sp., Lolium sp., Festuca arundinacea, and Dactylis glomerata; more preferably Trifolium sp., Medicago sativa, Triticum sp., Lolium sp., and Festuca arundinacea; even more preferably Trifolium sp., Medicago sativa, Triticum sp. and Lolium sp.

[0120] In the state of the art, various physiological and agronomic indices are commonly used to evaluate plant performance, growth, and stress responses, to assess the effects of seed treatments, seed coatings, or seed-applied compositions on plant development. Such indices provide quantitative or semi-quantitative information relating to photosynthetic efficiency, chlorophyll content, nutrient status, and biomass accumulation. Non-limiting examples of the present disclosure include the Chlorophyll Content Index (CCI), Photosynthetic Quantum Yield (Qy), Soil Plant Analysis Development (SPAD) values, and shoot dry weight, each of which allows to objectively determine physiological and growth-related effects of treatments applied at the seed level.

[0121] Chlorophyll Content Index (CCI) is a physiological parameter representing a relative measure of chlorophyll present in plant leaf tissue and is commonly used as an indicator of photosynthetic capacity, nitrogen status, and overall plant health. The index was determined using an MPM-100 Multi-Pigment Meter on fully expanded leaves of the plants. In the context of the present disclosure, CCI was used toassess the effect of the seed coating composition of the present disclosure on chlorophyll retention and photosynthetic performance of plants grown from treated seeds.

[0122] Photosynthetic Quantum Yield (Qy) is a measure of the efficiency with which absorbed light energy is converted into photochemical energy during photosynthesis and is particularly associated with the performance of photosystem II. Qy is determined by chlorophyll fluorescence measurements, typically using a pulse-amplitude-modulated fluorometer, following dark adaptation of the plant tissue. Minimum fluorescence (Fo) and maximum fluorescence (Fm) was recorded, and Qy was calculated according to the equation (Fm - Fo) / Fm. Within the present disclosure, Qy serves as an indicator of photosynthetic efficiency and plant tolerance to abiotic stress conditions resulting from the application of the disclosed seed treatments.

[0123] Soil Plant Analysis Development (SPAD) is a dimensionless index reflecting the relative chlorophyll content of leaves and is widely applied to estimate plant nitrogen status and physiological condition. SPAD values were obtained using an MPM-100 Multi-Pigment Meter on fully expanded leaves of the plants. In the present disclosure, SPAD measurements were used to quantify the physiological response of plants grown from treated seeds, particularly with respect to nutrient uptake and chlorophyll synthesis.

[0124] Shoot dry weight is an absolute measure of plant biomass accumulation in the aerial parts of the plant, including stems and leaves, and provides a direct assessment of vegetative growth. The shoot dry weight of the different embodiments of the present disclosure was determined by harvesting the shoot portion of the plant at a defined developmental stage, followed by drying the harvested material at elevated temperature until constant weight is achieved, and subsequently weighing the dried biomass. Results were expressed as grams per plant (g / plant) based on the average of the six biological replicates for each treatment. In the context of the present disclosure, shoot dry weight is employed as a quantitative parameter to demonstrate enhanced growth and biomass production resulting from the application of the disclosed seed coating or treatment compositions.

[0125] In an embodiment, the present disclosure relates to a seed coating composition comprising:Algae biomass as biofertilizer, soil stabilizer and plant biostimulator and bioprotector; andA binder to ensure adhesion of the algae biomass and the microbial inoculum to the seed surface and to maintain the mechanical integrity of the seed coating during handling, storage and sowing.

[0126] In a preferred embodiment, the seed coating further comprises a microbial inoculum as a delivery of beneficial microorganisms to the seeds.

[0127] In an embodiment for better results, the seed coating composition further comprises a drying agent to facilitate adhesion, stability, and handling of the coating on the seed surface.

[0128] In an embodiment, the seed coating composition of the present disclosure further comprises agriculturally acceptable additives and / or biostimulants and bioprotectors.

[0129] The disclosed seed coating composition exhibits a synergistic effect, because each component contributes with complementary functions that together enhance seed performance and plant development beyond the sum of their individual effects. Specifically, the binder ensures that the algae biomass and microbial inoculum are effectively delivered and maintained on the seed surface, the algae biomass provides nutrients, biostimulatory signals, and soil conditioning, the microbial inoculum establishes beneficial microbial interactions in the rhizosphere, and the optional additives and drying agents improve coating stability, functionality, and pH correction of the soil. Surprisingly, this integrated formulation results in enhanced seed germination, nutrient uptake, photosynthetic performance, stress tolerance, and vegetative growth, effects that cannot be achieved by any single component alone.

[0130] In an embodiment, the present disclosure relates to a seed coating composition comprising:Algae biomass wherein the algae biomass comprises at least one alga selected from a list consisting of: green algae (Chlorella vulgaris, Tetraselmis chuii and Ulva rigida) red alga (Gracilaria sp), brown algae (Tisochrysis lutea, Skeletonema sp and Thalassiosira pseudonana), cyanobacteria (Arthrospira platensis) or mixtures thereof; preferably Chlorella vulgaris, Tetraselmis chuii, Ulva rigida, Gracilaria sp., or Tisochrysis lutea; more preferably Chlorella vulgaris, Tetraselmis chuii, and Gracilaria sp. A microbial inoculum selected from a list consisting of: Rhizobium sp., Azospirillum sp., Bacillus sp., Pseudomonas sp.; preferably Rhizobium sp. or Azospirillum sp.; more preferably Rhizobium sp. A polymeric binder selected from natural or synthetic polymers capable of forming cohesive films or gels, such as gum Arabic, cellulose derivatives, alginate, xanthan gum, carrageenan, chitosan, or other hydrophilic biopolymers; preferablyArabic gum, cellulose derivatives, or alginate; more preferably Arabic gum; andA drying agent selected from limestone, dolomite, gypsum, perlite, clay minerals such as bentonite, or mixtures thereof; preferably preferably limestone, dolomite, or bentonite; more preferably limestone.

[0131] In an embodiment, the drying agents and the polymeric binder of the seed coating composition of the present disclosure are chosen for their functional characteristics, including pH buffering, physical stability, compatibility with the biomass and seed, and minimal adverse effect on beneficial microbial activity in or near the seed environment.

[0132] In an embodiment, the effective amount of algae biomass retained on the seed surface following coating and drying is:at least 45% (w / w) of the nominal coating load applied, representing a minimum effective retention; preferably at least 60% (w / w) of the nominal coating load applied, representing a preferred retention level; ormore preferably at least 70% (w / w) of the nominal coating load applied, representing the most preferred retention level.

[0133] In an embodiment, it is disclosed a coated seed comprising a surface coating, wherein the surface coating comprises:biomass from at least one alga selected from macroalgae, microalgae or cyanobacteria;a polymeric binder, selected from natural binders, synthetic binders, semi-synthetic binders, or combinations thereof;optionally, a microbial inoculum, selected from a list consisting of Rhizobiaceae, Bradyrhizobiaceae, Azotobacteraceae , and Pseudomonadaceae. or mixtures thereof;optionally, at least one drying agent selected from a list consisting of: inorganic drying agents, organic drying agents, polymeric drying agents, or combinations thereof.Wherein in the coated seed is obtainable by a method comprising the following steps:adding the polymeric binder in droplets on top of the seeds, preferably in an amount of 100-200 pL per 5 g of seeds, corresponding to a ratio sufficient to ensure adhesion of the coating components relative to the total weight of the coated seeds;manual mixing or shaking for up to 10 min the mixture obtained in the previous step; adding the algae biomass to the coated seeds obtained from the previous step, preferably in weight ratio between the biomass and the seeds ranges from 1:20 to 10:20, preferably 2:20 to 3:20; andmixing or shaking for up to 5 minutes.

[0134] In an embodiment, for a 100% nominal coating load, 500 to 2500 mg of biomass are added per 5 g of seeds; preferably 500 to 600 mg of biomass per 5 g of seeds.

[0135] In another embodiment, 100 to 500 mg of biomass are added per 5 g of seeds for a 50% nominal coating load, preferably 200 to 300 mg of biomass per 5 g of seeds. For the 50% coating, a drying agent (e.g., limestone, talc, or graphite) is added in an equal amount so that the total coating weight corresponds to the 100% nominal load.

[0136] In an embodiment, the seeds can be mixed with the microbial inoculum in a ratio of 20 mg per 5 g of seeds, corresponding to approximately 0.4% (w / w) relative to the total weight of the coating seeds, before the adding the polymeric binder.

[0137] In an embodiment, after the coating process, the coated seeds are preferably stored at 4 °C for at least 12 hours, which allows the binder and algal biomass to properly adhere and ensures uniform coating.Examples1. Coating clover, alfalfa, wheat and ryegrass seeds with algae biomass powder

[0138] Seeds from Persian clover (Trifolium resupinatum), alfalfa (Medicago sativa), wheat (Triticum aestivum), or ryegrass (Lolium multiflorum) were weighed and coated with the seed coating compositionas follows. A microbial inoculum (e.g., nitrogen-fixing bacteria, siderophore-producing bacteria, phosphate-solubilizing bacteria, etc.) was applied at a rate of 20 mg per 5 g of seeds, corresponding to approximately 0.4% (w / w) relative to the total weight of the coated seeds. Next, a binder (e.g., sugars, gums, celluloses, etc.) was added in a volume of 100-200 pL, applied as droplets on top of the seeds, followed by manual mixing or shaking for up to 10 minutes, preferably 2 minutes, to ensure uniform coating.

[0139] Subsequently, an effective amount of algae biomass was added at 600 mg for a 100% nominal coating load or 300 mg for a 50% nominal coating load, relative to the total weight of the coated seeds. In an embodiment, the algae biomass was applied alone for the 100% nominal coating load, whereas for the 50% nominal coating load, the algae biomass was mixed with a drying agent, such as talc, graphite, or limestone, in a 1:1 (w / w) ratio of drying agent to algae biomass, corresponding to 300 mg of algae biomass and 300 mg of drying agent per 5 g of seeds, thereby providing a total coating mass equivalent to the 100% nominal coating load. Other ratios may also be employed depending on the desired coating characteristics, preferably ranging from 1:2 to 2:1 (drying agent: algae biomass). In an embodiment, the algae biomass can be prepared in various forms, including fresh paste, sun-dried biomass, oven-dried biomass, freeze-dried biomass, or spray-dried biomass. Preferably, the algae biomass is provided as a powder, preferably an extremely fine powder, which is particularly suitable for uniform seed coating and effective adhesion to the seed surface.

[0140] For the scope and interpretation of the present disclosure, algae biomass refers to the total biological material obtained from microalgae or macroalgae, including whole cells and their structural components, produced through natural growth or controlled cultivation processes. An algae biomass extract is a product derived from algae biomass by physical, chemical, or biological extraction, wherein selected soluble or dispersible constituents are isolated from the biomass. Such a biomass extract may comprise one or more bioactive compounds, including proteins and peptides, amino acids, polysaccharides, oligosaccharides, lipids and fatty acids, pigments, vitamins, minerals, phytohormones, antioxidants, and other low- or high-molecular-weight metabolites, depending on the algal source and extraction method used.

[0141] As a control, a binder, an appropriate microbial inoculum, and a drying agent were used to coat the seeds following the same protocol as for the algae biomass, according to standard methods.

[0142] In a preferred embodiment, the seeds were coated using a microbial inoculum of Rhizobium sp., and Arabic gum as a binder to ensure adhesion of the inoculum and other coating components to the seed surface

[0143] Figure 1 illustrates non-limiting embodiments of clover (A), alfalfa (B) and ryegrass seeds (C) coated with different algae biomass.

[0144] In an embodiment, several seed coating compositions were developed and tested. Algae biomasses from different sources, identified as Chlorella vulgaris 1 (Cvl), Chlorella vulgaris 3 (Cv3), Spirulina platensis (Ap), Chlorella vulgaris 2 (Cv2), Skeletonema sp. (S), Tisochrysis lutea (Tl), Tetraselmis chuii (Tc), and with algae biomass mixtures, identified as Chlorella vulgaris 1 and Chlorella vulgaris 3 (CvlCv3), Tetraselmis chuii and Gracilaria sp. (TcG), and Ulva rigida, Chlorella vulgaris 2 and Tisochrysis lutea (UrCv2TI), as depicted in Table 1.

[0145] In an embodiment, each seed coating compositions was applied using a nominal coating load of either 50% or 100% (w / w) relative to the weight of the seeds, wherein for the 50% coating, the algae biomass was combined with a drying agent such that the total coating mass corresponded to the 100% nominal load.Table 1 - Seed coating compositions used in the embodiments of the present disclosure relative to the total weight of 5g of seeds. The binder is applied as an aqueous solution in an amount of 100-200 pL per 5 g of seeds, corresponding to approximately 2.0-4.0% (w / w) relative to the total seed weight.

[0146] In an embodiment, the tested seed coating composition identified as Cvl comprised 12 % (w / w) of Chlorella vulgaris 1 algae biomass obtained from cultivated algal biomass; 0.4 % (w / w) of the microbial inoculum consisting of Rhizobium sp.; and 2.0-4.0% (w / w) of Arabic gum as a binder. Percentages relative to relative to the total weight of 5g of seeds .

[0147] In an embodiment, the tested seed coating composition identified as Cv3 comprised 6 % (w / w) of Chlorella vulgaris 3 algae biomass obtained from cultivated algal biomass; 0.4 % (w / w) of the microbial inoculum consisting of Rhizobium sp.; 2.0-4.0% (w / w) of Arabic gum as a binder; and 6 % (w / w) of limestone as a drying agent. Percentages relative to relative to the total weight of 5g of seeds.

[0148] In an embodiment, the tested seed coating composition identified as Ap comprised 6-12% (w / w) of Spirulina platensis algae biomass obtained from cultivated algal biomass, corresponding to the 50% and 100% nominal coating loads; 0.4 % (w / w) of the microbial inoculum consisting of Rhizobium sp.; 2.0-4.0% (w / w) of Arabic gum as a binder; and, for the 50% nominal coating load only, 6 % (w / w) of limestone as a drying agent. Percentages relative to relative to the total weight of 5g of seeds

[0149] In an embodiment, the tested seed coating composition identified as Cv2 comprised 6-12% (w / w) of Chlorella vulgaris 2 algae biomass obtained from cultivated algal biomass, corresponding to the 50% and 100% nominal coating loads; 0.4 % (w / w) of the microbial inoculum consisting of Rhizobium sp.; 2.0-4.0% (w / w) of Arabic gum as a binder; and, for the 50% nominal coating load only, 6 % (w / w) of limestone as a drying agent. Percentages relative to relative to the total weight of 5g of seeds

[0150] In an embodiment, the tested seed coating composition identified as S comprised 12 % (w / w) of Skeletonema sp algae biomass obtained from cultivated algal biomass; 0.4 % (w / w) of the microbial inoculum consisting of Rhizobium sp.; and 2.0-4.0% (w / w) of Arabic gum as a binder. Percentages relative to relative to the total weight of 5g of seeds

[0151] In an embodiment, the tested seed coating composition identified as Tl comprised 6-12% (w / w) of Tisochrysis lutea algae biomass obtained from cultivated algal biomass, corresponding to the 50% and 100% nominal coating loads; 0.4 % (w / w) of the microbial inoculum consisting of Rhizobium sp.; 2.0-4.0% (w / w) of Arabic gum as a binder; and, for the 50% nominal coating load only, 6 % (w / w) of limestone as a drying agent. Percentages relative to relative to the total weight of 5g of seeds

[0152] In an embodiment, the tested seed coating composition identified as Tc comprised 6 % (w / w) of Tetraselmis chuii algae biomass obtained from cultivated algal biomass; 0.4 % (w / w) of the microbial inoculum consisting of Rhizobium sp.; 2.0-4.0% (w / w) of Arabic gum as a binder; 6 % (w / w) of limestone as a drying agent. Percentages relative to relative to the total weight of 5g of seeds

[0153] In an embodiment, the tested seed coating composition identified as CvlCvB comprised 9 % (w / w) of two algae biomasses Chlorella vulgaris 1 and Chlorella vulgaris 3 and a drying agent in a 2:1:1 (w / w / w) ratio, corresponding to 6.0% (w / w) of a first algae biomass, 3.0% (w / w) of a second algae biomass, and 3.0% (w / w) of drying agent, relative to the total seed weight; 0.4 % (w / w) of the microbial inoculum consisting of Rhizobium sp.; and 2.0-4% (w / w) of Arabic gum as a binder. Percentages relative to relative to the total weight of 5g of seeds

[0154] In an embodiment, the tested seed coating composition identified as TcG comprised 9 % (w / w) of two algae Tetraselmis chuii and Gracilaria sp. algae biomass and a drying agent in a 2:1:1 (w / w / w) ratio, corresponding to 6.0% (w / w) of a first algae biomass, 3.0% (w / w) of a second algae biomass, and 3.0% (w / w) of drying agent, relative to the total seed weight; 0.4 % (w / w) of the microbial inoculum consistingof Rhizobium sp. ; and 2.0-4% (w / w) of Arabic gum as a binder. Percentages relative to relative to the total weight of 5g of seeds

[0155] In an embodiment, the tested seed coating composition identified as UrCv2TI comprised 9 % (w / w) of three algae Ulva rigida, Chlorella vulgaris 2 and Tisochrysis lutea algae biomass and a drying agent in a 4:1:1:2 (w / w / w / w) ratio, corresponding to 6.0% (w / w) of a first algae biomass, 1.5% (w / w) of a second algae biomass, 1.5% (w / w) of a third algae biomass ,and 3.0% (w / w) of drying agent, relative to the total seed weight; 0.4 % (w / w) of the microbial inoculum consisting of Rhizobium sp. ; and 2.0-4% (w / w) of Arabic gum as a binder. Percentages relative to relative to the total weight of 5g of seeds 2. Clover and ryegrass seeds germination and plant growth in controlled conditions

[0156] Coated seeds were pre-germinated in distilled water for one day in the dark and three to seven days under a 16 h light / 8 h dark photoperiod at room temperature. In an embodiment, seedlings were then transplanted into alveoli filled with substrate Siro Relva (Siro, Portugal). Plants were placed in a climatic chamber at 22 °C under a 16 h light / 8 h dark photoperiod and 70% relative humidity. Plants were equally irrigated whenever necessary. Figure 2 shows clover plants four weeks after germination and Figure 3 shows ryegrass plants four weeks after germination in controlled conditions.

[0157] In another embodiment, clover, alfalfa and ryegrass seeds were sown directly into 3.5 L pots, respectively 0.70 L pots filled with substrate Siro Relva (Siro, Portugal), to evaluate plant growth. To replicate authentic field conditions, plants were grown in an open-air walk-in tunnel from January to June under natural environmental exposure— no artificial climate control or routine irrigation. Water was only supplied during extreme heatwaves in May - June to prevent irreversible drought stress, ensuring the crops experienced near-natural growing conditions. Two vegetative cuts were performed in sync with the plants' developmental stages to mirror standard field management practices.3. Evaluation of plant biochemical parameters in open-air walk-in tunnel

[0158] In an embodiment, to evaluate the direct physiological impacts of the seed coating composition of the present disclosure prior to cutting-induced stress reactions, essential biochemical parameters such as flavonoids, Chlorophyll Content Index (CCI), Photosynthetic Quantum yield (Qy) and Soil Plant Analysis Development (SPAD) values were assessed at the apex of vegetative growth, just before the first cutting. As a result, a standardized baseline for evaluating treatment efficacy was established by isolating the coating's influence on photoprotective compound synthesis and photosynthetic capacity, independent of post-cut metabolic interference, and it generated critical data supporting early-stage plant performance, as demonstrated in similar studies (Arezoo et al., 2023). This captured seed coatings' inherent ability to improve stress-reducing phytochemicals and photosynthetic capability during early growth, before the confusing impacts of regrowth dynamics or wound responses.

[0159] In an embodiment, statistical analyses were performed using R version 4.3.3 (2024-02-29) and R version 4.4.2 (2025-08-14). Continuous variables were subjected to hypothesis testing using either Oneway analysis of variance (ANOVA), Welch's ANOVA, or the Kruskal-Walli's test, based on the assumptions of normality (Shapiro's test) and heteroscedasticity (Levene's test). For count variables, Quasi-Poisson generalized linear models were employed to compare means between treatments. Fisher's exact test was applied to test significant differences between the proportions of the categories between treatments. The null hypothesis was rejected when the p-values were below the significance threshold of 0.05. The null hypothesis of equal means was rejected when the p-values were below the significance thresholds: p-value < 0.10, * p-value < 0.05, ** p-value < 0.01, *** p-value < 0.001.

[0160] Photosynthesis is the process by which plants use light as a source of energy, a process that can be quantified through photosynthetic quantum yield (Qy), using a FluorPen (Photon Systems Instruments). Statistical analysis was conducted as described above. Figure 4 illustrates non-limiting embodiments of the Qy of clover plants germinated from seeds coated with different algae biomasses at four weeks, normalized by the control in controlled conditions. Figure 5 illustrates non-limiting embodiments of the Qy of ryegrass plants germinated from seeds coated with different algae biomasses at four weeks, normalized by the control in controlled conditions.

[0161] The Chlorophyll Content Index (CCI) and Soil Plant Analysis Development (SPAD) value are both non-destructive, proxy measurements strongly correlate with total chlorophyll content. In the context of crop performance and biostimulation, elevated CCI / SPAD readings are indicative of enhanced photosynthetic capacity and improved nitrogen use efficiency.

[0162] A biostimulant treatment that reliably boosts chlorophyll (CCI / SPAD) is directly improving the plant's core function: photosynthesis. This often translates to improved light capture, carbon assimilation, and ultimately, increased biomass accumulation and yield potential, signifying successful nutrient uptake and metabolic enhancement. Figure 6 illustrates non-limiting embodiments of the quantification of chlorophyll content index of clover plants germinated from seeds coated with the previously identified seed coating compositions Cvl, Cv3 and UrCv2TI prior to the first cut, normalized by the control, which revealed that plants grown from coated seeds exhibited higher chlorophyll retention and enhanced photosynthetic performance compared to uncoated seeds in_open-air walk-in tunnel. Figure 7 illustrates non-limiting embodiments of the quantification of soil plant analysis development of clover plants germinated from seeds coated with the previously identified seed coating compositions Cvl, Cv3 and UrCv2TI prior to the first cut, normalized by the control, which demonstrated that plants grown from coated seeds showed improved nitrogen status and overall physiological condition relative to uncoated seeds in_open-air walk-in tunnel.

[0163] In an embodiment, building on the individual success of the Cvl and Cv3 coatings in enhancing clover performance, a synergistic mixture of the two powder biomasses was subsequently investigated in alfalfa (Medicago sativa). This combined embodiment was evaluated to determine potential additive or synergistic effects in a second leguminous crop. Promisingly, the CvlCv3 mixture also demonstrated significant potential in alfalfa, as evidenced by increased chlorophyll content, measured by both the Chlorophyll Content Index (CCI) and SPAD values. This positive response indicates that the mixed treatment effectively boosted photosynthetic capacity and plant vigor in alfalfa, mirroring the beneficial effects previously observed in clover and underscoring the broad applicability of these coating technologies across legume species. Figure 8 illustrates non-limiting embodiments of the quantification of chlorophyll content index of alfalfa plants germinated from seeds coated with the previously identified seed coating composition CvlCvB prior to the first cut, normalized by the control, which evidenced that plants grown from coated seeds exhibited increased chlorophyll content and enhanced photosynthetic performance compared to uncoated seeds in_open-air walk-in tunnel. Figure 9 illustrates non-limiting embodiments of the quantification of soil plant analysis development of alfalfa plants germinated from seeds coated with the previously identified seed coating composition CvlCvB prior to the first cut, normalized by the control, which established that plants grown from coated seeds demonstrated improved nitrogen status and overall physiological condition relative to uncoated seeds in_open-air walk-in tunnel.

[0164] Measuring flavonoids is crucial for evaluating biostimulation treatment. An increase in these compounds demonstrates that the treatment successfully enhances the plant's intrinsic stress resilience and antioxidant capacity, signifying an improved physiological state. Essentially, it reveals that the biostimulant isn't just making the plant grow bigger, it's making it stronger and healthier by priming its natural defense systems.

[0165] Figure 10 illustrates non-limiting embodiments of the quantification of flavonoids of clover plants germinated from seeds coated with the previously identified seed coating compositions Cvl, Cv3, CvlCvB and UrCv2TI prior to the first cut, normalized by the control, which provided that plants grown from coated seeds accumulated higher levels of flavonoids compared to plants grown from uncoated seeds, suggesting enhanced secondary metabolite production and potential stress resilience in_open-air walk-in tunnel..

[0166] In an embodiment, to assess the broad-spectrum efficacy and commercial potential of the seed coating composition of the present disclosure, it was investigated whether the treatments that demonstrated significant biostimulation in clover would elicit a similar response in alfalfa, another agronomically important legume. The replication of key positive results— including enhanced biomass, photosynthetic activity, and flavonoid production— confirms that the beneficial effects are not species-specific. This successful translation of results across legume species underscores the robustness and scalability of the coating technology for improving crop performance.

[0167] Figure 11 illustrates non-limiting embodiments of the quantification of flavonoids of alfalfa plants germinated from seeds coated with the previously identified seed coating compositions Cvl, Cv3, CvlCv3 and UrCv2TI prior to the first cut, normalized by the control, which confirmed that plants grown from coated seeds exhibited increased flavonoid accumulation compared to uncoated seeds, indicating enhanced secondary metabolite production and potential improvement in plant stress resilience in open-air walk-in tunnel .

[0168] In an embodiment, the efficacy of the seed coating composition was successfully extended to ryegrass, a gramineous species, confirming its broad applicability beyond legumes. The treatment elicited a consistent improvement in stress resilience, mirroring the positive effects observed in clover and alfalfa. This reproducible outcome across distinct plant families indicates that the underlying biostimulant mechanism operates effectively in diverse crops, underscoring its significant potential as a versatile tool for sustainable agriculture.

[0169] Figure 12 illustrates non-limiting embodiments of the quantification of chlorophyll content index of ryegrass plants germinated from seeds coated with the previously identified seed coating compositions Tl and UrCv2TI prior to the first cut, normalized by the control, which disclosed that plants grown from coated seeds exhibited higher chlorophyll content and improved photosynthetic performance compared to plants grown from uncoated seeds in open-air walk-in tunnel.

[0170] Figure 13 illustrates non-limiting embodiments of the quantification of soil plant analysis development of ryegrass plants germinated from seeds coated with the previously identified seed coating compositions Tl and UrCv2TI prior to the first cut, normalized by the control, which showed that plants grown from coated seeds exhibited improved nitrogen status and overall physiological condition compared to uncoated seeds in open-air walk-in tunnel.4. Plant growth and regrowth evaluation in open-air walk-in tunnel

[0171] In an embodiment, plant growth and regrowth were evaluated through two sequential cuts. For clover and alfalfa, the first cut was performed at 11 weeks post-sowing, while ryegrass was cut earlier at 7 weeks. After regrowth, a second cut was conducted— 5 weeks after the first cut for clover and alfalfa, and 8 weeks for ryegrass— to assess recovery and productivity under field-like conditions.

[0172] In an embodiment, the shoots were separated from the roots and dried at 60°C for at least 24 hours. After that period, shoot dry weight was evaluated for clover, alfalfa and ryegrass, whereas the nodulation of the roots was observed just in the case of clover plants. In another embodiment, statistical analyses were performed as described above. Figure 14 illustrates non-limiting embodiments of the growth and development of plants germinated from clover seeds coated with different algae biomassesdemonstrated by the shoot dry weight and Leaf Area Index (LAI), normalized by the control in controlled conditions. Figure 15 illustrates non-limiting embodiments of the growth and development of plants germinated from ryegrass seeds coated with different algae biomasses demonstrated by the shoot dry weight and number of tillers, normalized by the control in controlled conditions

[0173] In an embodiment, the total shoot dry matter production from two growth cycles, shown in Figure 16, for clover plants established from algal-coated seeds, with the previously identified seed coating compositions Cv3, CvlCv3 and UrCv2TI, with values normalized to the control, which revealed that plants grown from coated seeds accumulated higher shoot biomass compared to uncoated seeds, indicating enhanced vegetative growth and overall plant vigor in_open-air walk-in tunnel testing environment. .

[0174] Figure 17 illustrates non-limiting embodiments of the significant improvement in dry biomass yield (two cuts) from algal-coated clover seeds, with the previously identified seed coating compositions Cv3, CvlCv3 and UrCv2TI, with values normalized to untreated control, which provided that coated seeds produced consistently higher dry matter yields, demonstrating the effectiveness of the seed coating compositions in promoting plant growth and productivity in_open-air walk-in tunnel testing environment.

[0175] In another embodiment, the significant increase in biomass production observed in clover following seed coating was investigated as well in alfalfa (Medicago sativa) with the Cvl (Chlorella vulgaris 1) coating to evaluate its effect in a different legume species. The results confirmed a higher positive response, with Cvl-coated alfalfa plants demonstrating an increase in dry matter yield compared to the control. This successful translation of efficacy from clover to alfalfa underscores the robust and broadspectrum potential of the seed coating composition for enhancing productivity in leguminous crops.

[0176] Figure 18 illustrates non-limiting embodiments of the total shoot dry matter production from two growth cycles for alfalfa plants established from algal-coated seeds with the previously identified seed coating composition Cvl, with values normalized to the control, which showed that plants grown from coated seeds accumulated higher shoot biomass compared to uncoated seeds, indicating improved vegetative growth and overall plant vigor in_open-air walk-in tunnel testing environment.

[0177] Figure 19 illustrates non-limiting embodiments of the significant improvement in dry biomass yield (two cuts) from algal-coated alfalfa seeds with the previously identified seed coating composition Cvl, with values normalized to the untreated control, which indicated that coated seeds produced consistently higher dry matter yields, demonstrating the efficacy of the seed coating composition in promoting plant growth and productivity in_open-air walk-in tunnel testing environment.

[0178] In an embodiment, the observed synergy between enhanced growth and secondary metabolite synthesis, previously noted in legumes, was successfully replicated in ryegrass. This consistent response across divergent plant families (legumes and grasses) not only confirms the broad-spectrum potential of the coating technology but also points to a fundamental, conserved mode of action.

[0179] Figure 20 illustrates non-limiting embodiments the total shoot dry matter production from two growth cycles for ryegrass plants established from algal-coated seeds with the previously identified seed coating compositions Tc, Cv2, Tl and UrCv2TI, with values normalized to the control, which found that plants grown from coated seeds accumulated higher shoot biomass compared to uncoated seeds, indicating enhanced vegetative growth and overall plant vigor in_open-air walk-in tunnel testing environment.

[0180] Figure 21 illustrates non-limiting embodiments of the significant improvement in dry biomass yield (two cuts) from algal-coated ryegrass seeds with the previously identified seed coating compositions Tc, Cv2, Tl and UrCv2TI, with values normalized to the untreated control, which indicated that coated seeds produced consistently higher dry matter yields, demonstrating the effectiveness of the seed coating compositions in promoting plant growth and productivity in_open-air walk-in tunnel testing environment.5. Root nodules

[0181] In an embodiment, a qualitative assessmentwas employed to evaluate nodulation patterns across algal seed coating treatments. In legumes and a few other plants, nitrogen fixating bacteria live in symbiotic organs on the roots called nodules, and the ammonia produced by the bacteria is absorbed by the plant (Suzaki et al., 2015). Root nodules were quantified in the roots of four-week-old clover plants. Statistical analyses as described above. Figure 22 illustrates non-limiting embodiments of the number of root nodules of clover plants germinated from seeds coated with different algae biomasses at four weeks, normalized by the control.

[0182] In another embodiment, the root systems of sixteen-week-old clover plants displayed such extensive nodulation that accurate quantification was precluded by the sheer density and overlapping clusters of nodules. In this embodiment, the treatment with the previously identified Cv3 (Chlorella vulgaris 3) seed coating composition enhances nodulation across both controlled and field-like conditions as illustrated in Figure 23. In controlled environments, where quantitative assessment was feasible, Cv3 yielded a high increase in nodule count compared to the control. This positive effect was powerfully corroborated in open-field tunnel trial, where the treatment induced such a prolific proliferation of nodules that precise quantification became impractical. Despite this, a systematic qualitative assessment revealed a visually substantial improvement in nodule density and development on Cv3-treated roots compared to control plants, confirming the treatment's efficacy in a more complex, realistic growing environment.Effect of the seed coating composition on plant growth under abiotic stress in controlled conditions

[0183] In an embodiment, wheat seeds were coated and subjected to a controlled hydric stress experiment to evaluate the performance of the seed coating under abiotic stress conditions. Building upon the observed synergy between enhanced growth and stress resilience, which was consistentlyreplicated across divergent plant families like legumes and grasses, and the successful translation of efficacy from clover to ryegrass, which underscored the robust and broad-spectrum potential of the composition, the critical question of its stability under duress was addressed. Surprisingly, the coated seeds under water deficit conditions maintained a level of growth and vitality that was almost equivalent to the well-watered, non-coated control group. This result demonstrates not only a successful replication of the biostimulant effect in a new grass species but, more importantly, confirms the maintenance of the biostimulation under abiotic stress. This finding significantly strengthens the technology's value proposition, proving its potential to enhance productivity reliably, even in suboptimal environmental conditions.

[0184] In an embodiment, the phenotypic comparison of wheat plants grown from seeds coated with algae biomasses, is illustrated in Figure 24.

[0185] In an embodiment, the total shoot dry matter production of wheat plants established from algal-coated seeds with the previously identified seed coating compositions Tc and TcG is shown in Figure 25 for both hydric stress and non-stress conditions, with all values normalized to the uncoated control, and revealed that plants grown from coated seeds accumulated higher shoot biomass compared to uncoated seeds under both conditions, demonstrating enhanced vegetative growth and increased tolerance to water-limiting stress in controlled conditions environment.Effect of the seed coating composition on plant growth under biotic stress in controlled conditions

[0186] In an embodiment, to evaluate the efficacy of the seed coating composition treatments under biotic stress (against Pythium ultimum infection), coated seeds were pre-germinated in distilled water for one day in the dark and three days under a 16 h light / 8 h dark photoperiod at room temperature. Seedlings were then transplanted into pots filled with substrate Siro Relva previously pasteurized at 83 °C for 30 minutes and then inoculated with the oomycete Pythium ultimum (grown in millet mixed with clover seeds for enhanced virulence for two weeks at 25 °C) at 0.5% (w / w). Plants were placed in a dew chamber at 14°C during the day and 9 °C during the night, under a 16 h / 8 h photoperiod, to promote infection, and then transferred to a climatic chamber at 22 °C under a 16 h light / 8 h dark photoperiod, and 70% relative humidity. Plants were equally irrigated whenever necessary. Plants were evaluated for the presence of disease every week up to three weeks.

[0187] In an embodiment, to evaluate the efficacy of seed coating treatments against Pythium ultimum infection, disease progression was quantified using the Area Under the Curve (AUC) for each treatment (Jeger et Viljanen-Rollinson, 2001).

[0188] In an embodiment, beyond the significant bioprotective efficacy demonstrated previously by the Cv3 (Chlorella vulgaris 3) treatment against Pythium ultimum in controlled conditions, preliminary screening of other seed coatings has also yielded promising results. More alternative coatings exhibitedunder control conditions a measurable capacity to diminish pathogen virulence and enhance plant defense responses in controlled conditions.

[0189] In an embodiment, coated seeds exhibited different percentages of reduction in AUC compared to the infected control (P. ultimum alone), demonstrating suppressed disease progression. Notably, the AUC for coated treatments approached levels observed in the non-infected control (water alone), indicating near-complete mitigation of pathogen effects. These findings increase the potential for algalbased coatings in managing soil-borne diseases.

[0190] Figure 26, 27, 28, 29 and, 30 illustrate non-limiting embodiments of clover plants three weeks after transplant into substrate inoculated with Pythium ultimum and the disease index reported as the Area Under the Curve (AUC) of clover plants challenged by Pythium ultimum when compared to Control (not infected). Figure 28 illustrates the disease index reported as the Area Under the Curve (AUC) of clover plants challenged by Pythium ultimum when compared to Control (not infected).Proportion of the seed coating composition biomass effectively retained on the seed surface

[0191] In an embodiment, following coating and drying, the proportion of biomass effectively retained on the seed surface was determined gravimetrically.

[0192] In an embodiment, the retention of individual biomasses on seeds was observed to vary depending on the biomass type, the nominal coating load applied, and the seed species as depicted in Table 2. Biomass Cvl, applied at nominal coating loads of 100% (w / w), exhibited a retention on clover and alfalfa seeds in the range of approximately 90%-91%. Biomass Cv3, applied at nominal coating loads of 50% (w / w), exhibited retention on clover and alfalfa seeds in the range of approximately 80%-81%. Biomass Ap, applied at nominal coating loads of 50-100% (w / w) on clover seeds, exhibited retention in the range of approximately 48-53%.

[0193] Biomass Cv2, applied at nominal coating loads of 50-100% (w / w) on clover, wheat, and alfalfa seeds, exhibited retention in the range of approximately 66-96%. Biomass S, applied at a nominal coating load of 100% (w / w) on clover seeds, exhibited retention of approximately 72%. Biomass Tl, applied at nominal coating loads of 50-100% (w / w) on wheat and ryegrass seeds, exhibited retention in the range of approximately 48-75%. Biomass Tc, applied at nominal coating loads of 50-100% (w / w) on wheat and ryegrass seeds, exhibited retention in the range of approximately 88-94%.

[0194] In another embodiment, biomass mixtures applied in combinations of nominal coating loads ranging from 50-100% (w / w) showed retention on seeds within defined ranges. Mixture CvlCv3, applied in a 2:1 ratio, exhibited retention of approximately 81-90% on clover and alfalfa seeds. Mixture UrCv2TI, applied in a 4:1:1 ratio, exhibited retention in the range of approximately 54-59% on clover, alfalfa, and ryegrass seeds. Mixture TcG, applied in a 2:1 ratio, exhibited retention of approximately 85-89% on wheat seeds.

[0195] Table 2 presents an embodiment of results presented as normalized values relative to uncoated control seeds. Specifically, the parameters measured include the Chlorophyll Content Index (CCI), which reflects the relative chlorophyll content and photosynthetic capacity of the plants; the Flavonoids which indicates the efficiency of plant's defensive and metabolic health. In biostimulation and bioprotection studies, rising flavonoid levels are a positive biomarker, indicating successful induction of the plant's own protective systems, which is the cornerstone of sustainable crop management strategies; and the Soil Plant Analysis Development (SPAD) index, which provides a measure of leaf chlorophyll and nitrogen status. All measurements were performed on six biological replicates, and normalization to the uncoated control allows for direct comparison of the effects of the different seed coating compositions on plant physiological performance and growth.Table 2 - Results obtained with the embodiments of the present disclosure.

[0196] The term "comprising" whenever used in this document is intended to indicate the presence of stated features, integers, steps, components, but not to preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

[0197] Those skilled in the art will recognise or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. The scope of the present invention is not intended to be limited to the above description but rather is as set forth in the appended claims.

[0198] Where singular forms of elements or features are used in the specification of the claims, the plural form is also included, and vice-versa, if not specifically excluded. In the claims, articles such as 'a', 'an', and "they" may mean one or more than one unless indicated to the contrary or otherwise evident from the context. Claims or descriptions that include 'or' between one or more members of a group are considered satisfied if one, more than one, or all the group members are present in, employed in or otherwise relevant to a given product or process unless indicated to the contrary or otherwise evident from the context. The invention includes embodiments in which exactly one member of the group is present in, employed in or otherwise relevant to a given product or process. The invention also included embodiments in which more than one or all the group members are present in, employed in or otherwise relevant to a given product or process.

[0199] Furthermore, it is to be understood that the invention encompasses all variations, combinations and permutations in which one or more limitations, elements, clauses, descriptive terms, etc., from one or more of the claims or from relevant portions of the description is introduced into another claim. For example, any claim that is dependent on another claim can be modified to include one or more limitations found in any other claim that is dependent on the same base claim. Furthermore, when the claims recite a composition, it is to be understood that methods of using the composition for any of the purposes disclosed herein are included, and methods of making the composition according to any of the methods of making disclosed herein or other methods known in the art are included, unless otherwise indicated or unless it would be evident to one of ordinary skill in the art that a contradiction or inconsistency would arise.

[0200] Where ranges are given, endpoints are included. Furthermore, it is to be understood that unless otherwise indicated or otherwise evident from the context and / or the understanding of one of ordinary skill in the art, values that are expressed as ranges can assume any specific value within the stated ranges in different embodiments of the invention, to the tenth of the unit of the lower limit of the range, unless the context clearly dictates otherwise.

[0201] The disclosure should not be seen in any way restricted to the embodiments described and a person with ordinary skill in the art will foresee many possibilities to modifications thereof. The abovedescribed embodiments are combinable.

[0202] The following claims further set out particular embodiments of the disclosure.

[0203] References[1] Dmytryk, A., Michalak, I., Wilk, R., Chojnacka, K., Gorecka, H. and Gorecki, H., (2015) Innovative seed treatment with algae homogenate. Waste Biomass Valor. 6, 441-448.[2] Kumar, A., Chaurasia, U., Elshobary, M. E., Kumari, S., Hussain, T., Bharti, A. P., Maurya, D. K., Samanta, L. and El-Sheekh, M. (2022) Utilization of algae in crop improvement and crop protection for a better agricultural system. In M. El-Sheekh, N. Abdullah, and I. Ahmad (Eds.), Handbook of Research on Algae as a Sustainable Solution for Food, Energy, and the Environment (pp. 442-470). IGI Global Scientific Publishing.[3] Parmar, P., Kumar, R., Neha, Y. and Srivatsan, V. (2023) Microalgae as next generation plant growth additives: Functions, applications, challenges and circular bioeconomy based solutions. Front. Plant Sci.14,1073546.[4] Sohail, M., Pirzada, T., Opperman, C.H. and Khan, S.A. (2022) Green Chem. 24, 6052- 6085.[5] Skrzypczak, D., Jarzembowski, t., Izydorczyk, G., Mikula, K., Hoppe, V., Mielko, K.A., Pudelko-Malik, N., Mlynarz, P., Chojnacka, K. and Witek-Krowiak, A. (2021) Hydrogel alginate seed coating as an innovative method for delivering nutrients at the early stages of plant growth. Polymers, 13, 4233.[6] Suzaki, T., Yoro, E. and Kawaguchi, M. (2015) Leguminous plants: inventors of root nodules to accommodate symbiotic bacteria. Int. Rev. Cell. Mol. Biol. 316,111-158.[7] Wu, J.Y., Tso, R., Sze, T.H. and Sumanto, H. (2023) The utility of algae as sources of high value nutritional ingredients, particularly for alternative / complementary proteins to improve human health. Front. Nutr.10.

Claims

C L A I M S1. A coated seed comprising a surface coating, wherein the surface coating comprises:an algae biomass obtained from at least one alga selected from macroalgae, microalgae or cyanobacteria;a polymeric binder, selected from natural binders, synthetic binders, semi-synthetic binders, or combinations thereof;optionally, a microbial inoculum, selected from a list consisting of bacteria, fungi, yeasts, actinomycetes, cyanobacteria or mixtures thereof.

2. The coated seed according to the previous claim wherein the polymeric binder forms a continuous or semi-continuous matrix of the surface coating.

3. The coated seed according to any of the previous claims wherein the biomass and / or the microbial inoculum are embedded in the polymeric matrix.

4. The coated seed according to any of the previous claims wherein the surface coating covers at least part of the external surface of the seed.

5. The coated seed according to any of the previous claims wherein the surface coating comprises 35 to 85 % (w / w) of the algae biomass, preferably 40 to 80% (w / w).

6. The coated seed according to any of the previous claims wherein the algae biomass is from at least one alga selected from a list consisting of: green algae, red alga, brown algae, cyanobacteria, or mixtures thereof.

7. The coated seed according to the previous claims wherein the green algae is selected from Chlorella vulgaris, Tetraselmis chuii or Ulva rigida; the red alga is selected from Gracilaria sp; the brown algae is selected from Tisochrysis lutea, Skeletonema sp or Thalassiosira pseudonana; the cyanobacteria is selected from Arthrospira platensis.

8. The coated seed according to the any of the previous claims wherein the microbial inoculum comprises microorganisms from the families: Rhizobiaceae, Bradyrhizobiaceae, Azotobacteraceae , or Pseudomonadaceae; preferably Rhizobiaceae or Bradyrhizobiaceae; more preferably Rhizobiaceae.

9. The coated seed according to any of the previous claims wherein the microbial inoculum comprises microorganisms selected from the species: Rhizobium leguminosarum, Rhizobium etli, Rhizobiumphaseoli, Rhizobium tropici; preferably Rhizobium leguminosarum or Rhizobium etli; more preferably Rhizobium leguminosarum.

10. The coated seed according to any of the previous claims wherein the surface coating comprises 1 to 3 % (w / w) of the microbial inoculum preferably 2.4 to 2.8% (w / w).

11. The coated seed according to any of the previous claims wherein the polymeric binder is selected from a list consisting of Arabic gum, guar gum, xanthan gum, starch, alginate, cellulose derivatives, polyvinyl alcohol, polyvinylpyrrolidone, polyethylene glycol, acrylic polymers, carboxymethyl cellulose, hydroxypropyl methylcellulose, ethyl cellulose and mixtures thereof.

12. The coated seed according to any of the previous claims wherein the surface coating comprises 12- 30 % (w / w) of the polymeric binder, preferably 15-20% (w / w).

13. The coated seed according to any of the previous claims wherein the surface coating further comprises at least one drying agent, preferably 30 to 40% (w / w) of the at least one drying agent.

14. The coated seed according to any of the previous claims wherein the drying agent is an inorganic drying agent, organic drying agent, polymeric drying agent, or combinations thereof.

15. The coated seed according to the previous claim wherein the drying agent is selected from a list consisting of: limestone, calcium carbonate, dolomite, gypsum, perlite, bentonite, talc, kaolin, diatomaceous earth, silica, starch, cellulose, lignin, chitosan, polyacrylate polymers, polyvinyl alcohol, polyethylene glycol and mixtures thereof.

16. The coated seed according to any of the previous claims, wherein the surface coating further comprises additives selected from a list comprising biostimulants, nutrients, fertilisers, vitamins, minerals, growth promoters, wetting agents, solvents, buffers, stabilisers, osmoprotectants, solar protectants, excipients, surfactants, emulsifiers, preservatives, essential oils, microorganisms or mixtures thereof.

17. The coated seed according to any of the previous claims, wherein the algae biomass is a dried powder or a paste, preferably a powder.

18. The coated seed according to any of the previous claims wherein the seed is of a plant belonging to the families: Poaceae, Fabaceae, Brassicaceae, and Solanaceae; preferably Poaceae or Fabaceae.

19. The coated seed according to the previous claim wherein the seed is from wheat, oat, barley, ryegrass, millet, clover, beans, soybean, peas, chickpeas, alfalfa, or fenugreek; preferably wheat, ryegrass, clover, or alfalfa.

20. A kit comprising the coated seed described in any of the previous claims.

21. Kit for obtaining the coated seed described in any of the previous claims comprising a biomass from at least one algae, and a polymeric binder, optionally a microbial inoculum and / or a drying agent.

22. A seed coating composition to obtain the coated seed described in any previous of the claims 1 to 19 comprising:35 to 85% (w / w) of algae biomass obtained from macroalgae, microalgae or cyanobacteria, or mixtures thereof; and12 to 30% (w / w) of a polymeric binder selected from natural binders, synthetic binders, semisynthetic binders, or combinations thereof; andOptionally, 1 to 3% (w / w) of microbial inoculum selected from a list consisting of bacteria, fungi, yeasts, actinomycetes, cyanobacteria or mixtures thereof.

23. The seed coating composition according to the previous claim, wherein the seed coating composition is a powder, a granulate, a slurry, a film forming formulation, a wettable powder, a sprayable formulation, a suspension concentrate, an emulsion, or an aqueous solution.

24. The seed coating composition according to any of the previous claims 22-23 further comprising at least one drying agent, preferably 30 to 40% (w / w) of the at least one drying agent, more preferably 35% (w / w) of the at least one drying agent.

25. The seed coating composition according to any of the previous claims 22-24 wherein the drying agent is selected from a list consisting of: limestone, calcium carbonate, dolomite, gypsum, perlite, bentonite, talc, kaolin, diatomaceous earth, silica, starch, cellulose, lignin, chitosan, polyacrylate polymers, polyvinyl alcohol, polyethylene glycol and mixtures thereof.

26. The seed coating composition according to any of the previous claims, wherein the retention of the coating composition on seeds ranges from 45-100%; preferably 60-100%; more preferably 70-100%.

27. Use of the seed coating composition according to the previous claims 22-26 as a plant biostimulant composition, a plant protector composition, a fertilizer composition, an insecticide composition, a pesticide composition, or a film-coating composition.

28. A method for obtaining the coated seed according to the previous claims 1 to 19, from the coating composition according to any of the previous claims 22-26 comprising the following steps: adding dropwise a polymeric binder to the seeds, preferably in an amount of 100-200 pL per 5 g of seeds;manual mixing or shaking for up to 10 minutes the mixture obtained in the previous step; adding an algae biomass to the seeds obtained from the previous step, preferably wherein the weight ratio between the biomass and the seeds ranges from 1:20 to 10:20, preferably 2:20 to 3:20; and mixing or shaking the obtained seeds for up to 5 minutes to obtain the coated seeds.

29. The method according to the previous claim further comprising a step of mixing the seeds with a microbial inoculum in a ratio of 20 mg per 5 g of seeds before adding the polymeric binder.

30. The method according to the previous claim further comprising a step of adding a drying agent, preferably 100 to 500 mg of drying agent per 5 g of seeds.

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