Oligosaccharide multifunctional plant immunomodulator

Abstract

The invention provides an oligosaccharide multifunctional plant immunomodulator, and particularly, the oligosaccharide multifunctional plant immunomodulator has a structure as shown in a formula I in the specification. The plant immunomodulator can regulate the growth and development of crops and induce the crops to generate resistance to biological and abiotic stress, so that the yield and quality of the crops are improved. By using the plant immunomodulator disclosed by the invention, the growth and development processes of a plurality of plants can be positively regulated, including promoting seed germination, seedling morphological establishment and growth vigor in an adult-plant stage, so that the crop yield and the fruit quality are improved; and the resistance of plants to biological stress (diseases, insects and weeds) and abiotic stress (drought, water stain, salt and alkali, extreme low temperature / high temperature and the like) can be improved. In addition, the plant immunomodulator also has the advantages of no toxicity, no pesticide residue, environmental friendliness, no drug resistance of pathogenic bacteria and the like. # imgabs0 #

Description

Technical Field

[0001] The present invention belongs to the field of oligosaccharide plant growth regulators, specifically relates to the fields of plant growth and development regulation and plant immune regulators, and particularly relates to a multifunctional oligosaccharide plant immune regulator. Background Art

[0002] In 1985, Albersheim, the director of the Carbohydrate Research Center in the United States, first proposed the concept of oligosaccharin, believing that certain bioactive oligosaccharides can stimulate the immune system response of plants and have functions in regulating plant growth, development, reproduction, disease prevention and resistance. At present, through a series of studies, researchers have found some saccharide substances with clear structures and targets and having plant immune regulation activities, such as trehalose, chitosan, etc.

[0003] In terms of regulating plant growth and development, oligosaccharide regulators not only provide energy and nutrients for plants, but also act as a signal molecule. As a signal molecule, oligosaccharides activate multiple signal response pathways such as plant hormones and calmodulin in cells, regulate the expression of a series of downstream target genes, cause corresponding physiological and biochemical changes, thereby regulating plant growth and development, including aspects such as seed germination, axillary bud growth, and leaf senescence, and at the same time enhancing the resistance of plants to abiotic stresses (such as salinity, drought, extreme temperatures, etc.), and ultimately improving the yield and quality of crops. On the other hand, oligosaccharide plant immune regulators stimulate plant immune defense by mimicking the signal molecules triggered when pathogens attack plants. During the interaction process between plants and pathogens, a series of specific or broad-spectrum recognition functions are realized by releasing oligomers derived from plant and pathogen cell walls (including pectin and chitin derivatives respectively), stimulating the signal cascade reaction of plant immune response, achieving the effects of "sugar immunity" and "sugar-enhanced defense".

[0004] As a new type of plant growth regulator, oligosaccharide plant immune regulators have a wide range of effects. They not only promote plant growth and development, improve the abiotic stress resistance of plants, but also have broad-spectrum antibacterial properties. Oligosaccharide plant immune regulators have many advantages, such as low use concentration, harmless to humans, no residue, environmentally friendly, significant disease resistance effect, long-lasting effect, no drug resistance generated by pathogens, and no impact on non-pathogenic microorganisms. In addition, oligosaccharide plant immune regulators can also be used in combination with conventional chemical fungicides, reducing the use amount of chemical pesticides, which is beneficial to ecological balance and environmental protection.

[0005] At present, the commercially available biopesticides (such as carbohydrate plant growth regulators) mainly focus on chitosan oligosaccharide, mainly targeting the harm of pathogenic bacteria. Their functions are generally relatively single and the usage cost is relatively high compared to traditional pesticides. Their structures contain multiple amino sugars. However, due to their mostly linear structures, their structural diversity is limited, resulting in slow progress in the modification of their structures and the optimization of their biological activities. Summary of the Invention

[0006] The object of the present invention is to provide an oligosaccharide-based multifunctional plant immune regulator.

[0007] In the first aspect of the present invention, a plant immune regulator is provided, which has the structure shown in Formula I:

[0008]

[0009] In Formula I,

[0010] R1 is selected from H, R3-C(O)-;

[0011] R2 is selected from H, C1-C6 alkyl;

[0012] R3 is selected from H, C1-C6 alkyl and C6-C14 aryl.

[0013] In the second aspect of the present invention, a pesticide composition is provided, and the pesticide composition includes the plant immune regulator described in the first aspect of the present invention and a pharmaceutically acceptable carrier.

[0014] In the third aspect of the present invention, the application of the plant immune regulator described in the first aspect of the present invention and the pesticide composition described in the second aspect of the present invention in regulating plant growth, development, reproduction, disease prevention and / or disease resistance is provided.

[0015] In the fourth aspect of the present invention, a method for regulating plant growth, development, reproduction, disease prevention and / or disease resistance is provided, and the method includes applying the plant immune regulator described in the first aspect of the present invention or the pesticide composition described in the second aspect of the present invention to the plant.

[0016] In one or more embodiments, the application includes seed soaking and / or spraying. Brief Description of the Drawings

[0017] Figure 1 (a) shows the phenotypic changes of dicotyledonous plants (soybean, peanut) and monocotyledonous plants (corn, wheat) after soaking in XT2401 (pentasaccharide) for 1 h; Figure 1 (b) shows the phenotypic changes of dicotyledonous plants (soybean, peanut) and monocotyledonous plants (corn, wheat) after soaking in XT2401 (pentasaccharide) for 6 h.

[0018] Figure 2 The phenotypic temporal changes are induced by soaking rapeseed seeds in XT2401 (penta - saccharide).

[0019] Figure 3 The dynamic changes in the germination of 'Zhongmai 578' seeds soaked in different concentrations of XT2401 (penta - saccharide).

[0020] Figure 4 The dynamic changes in the emergence of wheat variety 'Zhongmai 578' seeds treated by soaking in XT2401.

[0021] Figure 5 XT2401 repairs the diseased parts of cucumbers.

[0022] Figure 6 XT2401 treatment improves the salt - alkali stress tolerance of cucumbers.

[0023] Figure 7 The comparative experiment on the promotion of rapeseed seed germination by XT2401 (penta - saccharide) and GAP9805 (di - saccharide) products.

[0024] Figure 8 The proton nuclear magnetic resonance spectrum of the prepared XT2401 (penta - saccharide). Detailed implementation mode

[0025] To enable those skilled in the art to understand the features and effects of the present invention, the following provides a general description and definition of the terms and phrases mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meanings understood by those skilled in the art regarding the present invention. In case of conflicts, the definitions in this specification shall prevail.

[0026] The theories or mechanisms described and disclosed herein, whether correct or incorrect, shall not limit the scope of the present invention in any way, that is, the content of the present invention can be implemented without being limited by any specific theory or mechanism.

[0027] The applicant prepared a series of Lewis X oligosaccharides through chemical synthesis means and studied their biological activities in detail. Lewis X oligosaccharides containing fucose - modified Lewis antigens (Lewis X oligosaccharides) are common structural units of cell - surface glycans and play crucial roles in many physiological and pathological processes. Research shows that Lewis XThe development and wide application of oligosaccharide biological pesticides will surely play its unique and due role in the sustainable development of China's agriculture and the health of human life. It will not only bring certain economic benefits to China's agriculture, but also produce extremely profound environmental protection and social benefits, with broad development prospects.

[0028] In this article, terms such as "comprising", "including", "containing" and similar terms cover the meanings of "consisting essentially of" and "consisting of". For example, when this article discloses that "A comprises B and C", "A consists essentially of B and C" and "A consists of B and C" should be considered to have been disclosed in this article.

[0029] In this article, all features defined in the form of numerical ranges or percentage ranges, such as numerical values, quantities, contents and concentrations, are only for the sake of simplicity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be regarded as having covered and specifically disclosed all possible sub-ranges and individual numerical values (including integers and fractions) within the ranges.

[0030] In this article, unless otherwise specified, the percentage refers to the mass percentage and the ratio refers to the mass ratio.

[0031] In this article, when describing the embodiments or examples, it should be understood that it is not used to limit the present invention to these embodiments or examples. On the contrary, all alternatives, modifications and equivalents of the methods and materials described in the present invention can be covered within the scope defined by the claims.

[0032] In this article, for the sake of concise description, all possible combinations of all technical features in each embodiment or example are not described. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each embodiment or example can be combined arbitrarily, and all possible combinations should be considered to be within the scope described in this specification.

[0033] In this article, as used herein, "alkyl" refers to a straight-chain or branched-chain monovalent saturated hydrocarbon group having a specified number of carbon atoms. Specific alkyl groups are those having 1 to 6 carbon atoms ("C1-C6 alkyl"), usually containing 1-5 carbon atoms (C1-C5 alkyl), preferably containing 1-4 carbon atoms (C1-C4 alkyl), and more preferably containing 1-3 carbon atoms (C1-C3 alkyl). Examples of alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, etc.

[0034] As used herein, "aryl" or "Ar" refers to an unsaturated aromatic carbocyclic group having a single ring (e.g., phenyl) or multiple fused rings (e.g., naphthyl or anthryl), where the fused rings may or may not be aromatic. In one variation, aryl contains 6 to 14 ring carbon atoms, preferably C6-C10 aryl. Examples of aryl include phenyl (Ph), naphthyl, phenanthryl, anthryl, indenyl, azulenyl, biphenyl, biphenylene, and fluorenyl.

[0035] As used herein, "Ac" represents acetyl.

[0036] The plant immunomodulator of the present invention

[0037] The present invention provides a plant immunomodulator having the structure shown in Formula I:

[0038]

[0039] In Formula I,

[0040] R1 is selected from H, R3-C(O)-;

[0041] R2 is selected from H, C1-C6 alkyl;

[0042] R3 is selected from H, C1-C6 alkyl, and C6-C14 aryl.

[0043] In some embodiments, R1 is selected from H, H-C(O)-, C1-C4 alkyl-C(O)-, and C6-C10 aryl-C(O)-. Preferably, R1 is selected from H-C(O)-, C1-C2 alkyl-C(O)-, and C6-C10 aryl-C(O)-. More preferably, R1 is selected from CH3-C(O)- and Ph-C(O)-.

[0044] In some embodiments, R2 is C1-C4 alkyl, such as C1-C2 alkyl, preferably methyl.

[0045] In some embodiments, the plant immunomodulator of the present invention is XT2401:

[0046]

[0047] Pesticide composition

[0048] The plant immune regulator of the present invention can positively regulate multiple plant growth and development processes, including promoting seed germination, seedling morphogenesis, and growth vigor during the adult plant stage, improving crop yield and fruit quality; and can also improve the resistance of plants to biotic stresses (diseases, pests, and weeds) and abiotic stresses (drought, waterlogging, salinity, extreme low / high temperature, etc.). Therefore, the present invention provides a pesticide composition containing the plant immune regulator of the present invention. The pesticide composition of the present invention includes the plant immune regulator of the present invention and a pesticide-acceptable carrier. In some embodiments, the pesticide-acceptable carrier is water, Hoagland nutrient solution, or Murashige and Skoog medium (MS medium).

[0049] The pesticide composition of the present invention can be processed into a soluble powder or granule by a general method in the art.

[0050] In some embodiments, the pesticide composition of the present invention further includes other pesticides and / or fertilizers. In some embodiments, the other pesticide can be a plant growth regulator. The plant growth regulator can be synthesized artificially, extracted artificially, or produced by biological fermentation. The plant growth regulator is an active substance similar to or opposite to plant endogenous hormones. At low concentrations, it can affect the synthesis, transport, metabolism, and physiological functions of plant endogenous hormones and can be used to regulate the growth and development of plants. The plant growth regulator can be selected from one or more of 2,4-D (2,4-dichlorophenoxyacetic acid), naphthaleneacetic acid, polyamines (such as spermine, spermidine, putrescine), cytokinins (such as 6-BA (benzylaminopurine), ZT (zeatin), KT30, CPPU (forchlorfenuron), or TDZ (thidiazuron)), mepiquat chloride, maleic hydrazide, paclobutrazol, chlormequat chloride, and abscisic acid. Excessive or improper use of existing plant growth regulators may damage the safety and effectiveness of crops and also have an adverse impact on the soil and water bodies in the production area. Combining the plant immune regulator of the present invention with a plant growth regulator can greatly reduce the dosage of the plant growth regulator in the pesticide composition and thereby reduce the adverse effects of the plant growth regulator.

[0051] Application

[0052] The present invention also provides the use of the plant immune regulator of the present invention and / or the pesticide composition of the present invention in regulating plant growth, development, reproduction, disease prevention, and / or disease resistance.

[0053] In some embodiments, the plant can be selected from one or more of soybean, peanut, rapeseed, corn, wheat, cucumber, and rice.

[0054] In some embodiments, regulating plant growth, development, reproduction, disease prevention and / or disease resistance is selected from: promoting seed germination, promoting seedling morphogenesis, promoting the growth of adult plants, promoting plant damage repair, increasing crop yield, improving fruit quality, enhancing the resistance of plants to biotic stresses, and enhancing the resistance of plants to abiotic stresses. In some embodiments, the biotic stresses include one or more of diseases, insect pests, and weeds. In some embodiments, the abiotic stresses include one or more of drought, waterlogging, salinity, extreme low temperature, and extreme high temperature.

[0055] As used herein, "extreme low temperature" and "extreme high temperature" refer to temperatures that are not within the suitable temperature range for plant growth and development and severely affect and / or inhibit plant growth, development, or reproduction. Among them, the extreme low temperature is lower than the suitable temperature for plant growth and development. The extreme high temperature is higher than the suitable temperature for plant growth and development. "Extreme low temperature" and "extreme high temperature" are related to the suitable temperature for plant growth and development and thus are also related to the plant variety. For example, the suitable growth temperature range for rapeseed is 20 - 25°C. Low temperatures below 10°C can severely inhibit growth, and high temperatures of 35°C also seriously affect its growth. Therefore, for rapeseed, the extreme low temperature refers to ≤10°C, and the extreme high temperature refers to ≥35°C. The suitable growth temperature range for rice is 25 - 30°C. When the environmental temperature is below 15°C, the growth and development of rice are affected. Therefore, for rice, the extreme low temperature refers to ≤15°C. In the art, the suitable growth temperature range for general plants is 15 - 30°C. Temperatures outside this suitable range are extreme low temperatures or extreme high temperatures. As used herein, the extreme low temperature is ≤15°C. As used herein, the extreme high temperature is ≥30°C.

[0056] In some embodiments, the present invention provides the use of the plant immune regulator of the present invention and the pesticide composition of the present invention in promoting the germination of plant seeds. As used herein, seed germination refers to seed sprouting. The plants are as described in any embodiment of the present invention, and are preferably selected from one or more of rice, cucumber, soybean, peanut, rapeseed, corn, and wheat.

[0057] The present invention provides the use of the plant immune regulator of the present invention and the pesticide composition of the present invention in promoting the emergence of plant seeds. The plants are as described in any embodiment of the present invention, and are preferably selected from one or more of corn, wheat, and peanut.

[0058] The present invention provides the use of the plant immune regulator of the present invention and the pesticide composition of the present invention in increasing plant yield. The plants are as described in any embodiment of the present invention, and are preferably selected from one or more of corn, wheat, rice, rapeseed, cucumber, and peanut.

[0059] The present invention provides the use of the plant immune regulator of the present invention and the pesticide composition of the present invention in promoting plant damage repair. The plant is as described in any embodiment of the present invention, preferably cucumber.

[0060] The present invention provides the use of the plant immune regulator of the present invention and the pesticide composition of the present invention in enhancing the response of plants to stress. The plant is as described in any embodiment of the present invention, preferably one or more of rape, cucumber and rice. The stress includes growing in saline-alkali land and / or encountering extreme low temperature. The extreme low temperature is a temperature ≤ 15°C, for example, the temperature is 0 - 15°C, 5 - 15°C, 7 - 15°C.

[0061] Method

[0062] The plant immune regulator of the present invention and / or the pesticide composition of the present invention can regulate plant growth, development, reproduction, disease prevention and / or disease resistance. Therefore, the present invention also provides a method for regulating plant growth, development, reproduction, disease prevention and / or disease resistance. The method includes applying the plant immune regulator of the present invention or the pesticide composition of the present invention to the plant. In some embodiments, the application includes seed soaking and / or spraying.

[0063] In some embodiments, the plant, the regulation of plant growth, development, reproduction, disease prevention and / or disease resistance are as described in any embodiment herein.

[0064] In some embodiments, the spraying method is as follows: after the cotyledons of the plant are flat, evenly spray the plant immune regulator solvent or the pesticide composition on both the front and back sides of the cotyledons until there is solution dripping like water drops, spray once a day for 4 - 8 days.

[0065] In some embodiments, the seed soaking method is as follows: place the plant seeds in the plant immune regulator solvent or the pesticide composition for seed soaking, dry them back, and then directly sow. The seed soaking time can be adjusted according to the variety of the plant.

[0066] The present invention provides a method for promoting the germination of plant seeds. The method includes soaking the plant seeds in a plant immunomodulator solvent or a pesticide composition. The concentration of the plant immunomodulator in the plant immunomodulator solvent or the pesticide composition can be 0.08 - 0.12 mg / L, such as 0.09 - 0.11 mg / L or 0.1 mg / L. The plants are as described in any embodiment of the present invention, and are preferably selected from one or more of rice, cucumber, soybean, peanut, rapeseed, corn and wheat. In some embodiments, the rice seeds are soaked in the plant immunomodulator solvent or the pesticide composition for 20 - 28 hours, such as 24 - 25 hours, and the concentration of the plant immunomodulator in the plant immunomodulator solvent or the pesticide composition is 0.09 - 0.11 mg / L. In some embodiments, the cucumber seeds are soaked in the plant immunomodulator solvent or the pesticide composition for 20 - 28 hours, such as 24 - 25 hours, and the concentration of the plant immunomodulator in the plant immunomodulator solvent or the pesticide composition is 0.09 - 0.11 mg / L. In some embodiments, the peanut seeds are soaked in the plant immunomodulator solvent or the pesticide composition for 3 - 3.5 hours, and the concentration of the plant immunomodulator in the plant immunomodulator solvent or the pesticide composition is 0.09 - 0.11 mg / L. In some embodiments, the corn seeds are soaked in the plant immunomodulator solvent or the pesticide composition for 5 - 7 hours, preferably soaked for 6 hours, and the concentration of the plant immunomodulator in the plant immunomodulator solvent or the pesticide composition is 0.09 - 0.11 mg / L. In some embodiments, the wheat seeds are soaked in the plant immunomodulator solvent or the pesticide composition for 5 - 7 hours, preferably soaked for 6 hours, and the concentration of the plant immunomodulator in the plant immunomodulator solvent or the pesticide composition is 0.09 - 0.11 mg / L. In some embodiments, the soybean seeds are soaked in the plant immunomodulator solvent or the pesticide composition for 20 - 30 minutes, and the concentration of the plant immunomodulator in the plant immunomodulator solvent or the pesticide composition is 0.09 - 0.11 mg / L. In some embodiments, the rapeseed seeds are soaked in the plant immunomodulator solvent or the pesticide composition for 15 - 20 minutes, and the concentration of the plant immunomodulator in the plant immunomodulator solvent or the pesticide composition is 0.09 - 0.11 mg / L. In some embodiments, the wheat seeds are soaked in the plant immunomodulator solvent or the pesticide composition for 6.5 - 7.5 hours, and the concentration of the plant immunomodulator in the plant immunomodulator solvent or the pesticide composition is 0.10 - 0.13 mg / L. In some embodiments, the wheat seeds are soaked in the plant immunomodulator solvent or the pesticide composition for 6.5 - 7.5 hours, and the concentration of the plant immunomodulator in the plant immunomodulator solvent or the pesticide composition is 0.05 - 0.08 mg / L.

[0067] The present invention provides a method for promoting the emergence of plant seeds. The method includes soaking plant seeds in a plant immune regulator solvent or a pesticide composition. The plant is as described in any embodiment of the present invention, and is preferably selected from one or more of corn, wheat, and peanut. The concentration of the plant immune regulator in the plant immune regulator solvent or the pesticide composition can be 0.10 - 0.13 mg / L, for example, 0.11 - 0.12 mg / L. In some embodiments, wheat seeds are soaked in the plant immune regulator solvent or the pesticide composition for 5.5 - 6.5 hours, and the concentration of the plant immune regulator in the plant immune regulator solvent or the pesticide composition is 0.10 - 0.13 mg / L. In some embodiments, peanut seeds are soaked in the plant immune regulator solvent or the pesticide composition for 5.5 - 6.5 hours, and the concentration of the plant immune regulator in the plant immune regulator solvent or the pesticide composition is 0.10 - 0.13 mg / L. In some embodiments, corn seeds are soaked in the plant immune regulator solvent or the pesticide composition for 7.5 - 8.5 hours, and the concentration of the plant immune regulator in the plant immune regulator solvent or the pesticide composition is 0.10 - 0.13 mg / L.

[0068] The present invention provides a method for increasing plant yield. The method includes soaking the seeds of a plant in a plant immune regulator solvent or a pesticide composition and / or spraying the plant immune regulator solvent or the pesticide composition on the plant. The plant is the above-ground part of the plant, such as a seedling. The plant is as described in any embodiment of the present invention, and is preferably selected from one or more of corn, wheat, rice, rapeseed, cucumber, and peanut. The concentration of the plant immune regulator in the plant immune regulator solvent or the pesticide composition for soaking the seeds of the plant can be 0.08 - 0.13 mg / L, for example, 0.10 - 0.12 mg / L or 0.11 mg / L. The concentration of the plant immune regulator in the plant immune regulator solvent or the pesticide composition for spraying the plant can be 0.0005 - 0.0006 mg / L. In some embodiments, the plant immune regulator solvent or the pesticide composition for spraying the plant is a 1800 - 2000-fold dilution of a stock solution with a plant immune regulator concentration of 1 mg / L. In some embodiments, the plant immune regulator solvent or the pesticide composition for soaking the seeds of the plant is a 9 - 10-fold dilution of a stock solution with a plant immune regulator concentration of 1 mg / L.

[0069] The present invention provides a method for promoting plant damage repair. The method includes spraying the damaged part of the plant with the solvent of the plant immunomodulator or the pesticide composition of the present invention. The solvent of the plant immunomodulator or the pesticide composition can be a 800 - 2000-fold dilution of the mother liquor with a concentration of 1 mg / L of the plant immunomodulator. The plant is as described in any embodiment of the present invention, preferably cucumber. The part of the plant after cutting off the diseased tissue is the damaged part. In some embodiments, the diseased tissue is a leaf.

[0070] The present invention provides a method for enhancing the response of plants to stress. The method includes soaking the seeds of the plant in the solvent of the plant immunomodulator or the pesticide composition and / or spraying the plant with the solvent of the plant immunomodulator or the pesticide composition. The plant, stress, and plant are as described in any embodiment of the present invention. In some embodiments, the concentration of the plant immunomodulator in the solvent of the plant immunomodulator or the pesticide composition for soaking the seeds of the plant is 0.1 - 1.2 mg / L, preferably 0.1 - 1.0 mg / L. In some embodiments, the concentration of the plant immunomodulator in the solvent of the plant immunomodulator or the pesticide composition for spraying the plant is 0.005 - 0.03 mg / L, preferably 0.01 - 0.02 mg / L.

[0071] The present invention has the following beneficial effects:

[0072] The present invention provides a new non-toxic and harmless plant immunomodulator, which can not only regulate the growth and development of crops but also induce the crops to produce resistance to biological and abiotic stresses, thereby improving the yield and quality of crops.

[0073] Using the plant immunomodulator of the present invention can not only positively regulate multiple plant growth and development processes, including promoting seed germination, seedling morphological establishment, and growth vigor during the adult stage, improving crop yield and fruit quality; but also improve the resistance of plants to biological stresses (diseases, pests, and weeds) and abiotic stresses (drought, waterlogging, salinity, extreme low / high temperature, etc.). And the plant immunomodulator of the present invention also has the advantages of being non-toxic, having no pesticide residues, being environmentally friendly, and not causing the pathogens to develop drug resistance. The plant immunomodulator of the present invention has a convenient use method and can be directly used for seed soaking treatment or spraying on plants.

[0074] The present invention provides a brand-new broad-spectrum Lewis X oligosaccharide plant growth regulator, which can effectively stimulate the immune defense system of plants to improve the basic immune response level of plants to diseases and extreme environmental stresses, and can simultaneously participate in multiple processes affecting the immune defense and growth and development of plants. Lewis X oligosaccharide contains a variety of monosaccharide fragments, making it easier to achieve structural modification and activity optimization. As a new type of biological pesticide, LewisX Oligosaccharides exhibit unprecedented advantages in structure and function.

[0075] The following further elaborates the present invention in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. The experimental methods without specific conditions noted in the following embodiments are generally carried out under conventional conditions or according to the conditions recommended by the manufacturer. Unless otherwise specified, percentages and parts are calculated by weight.

[0076] In this article, the solvents of XT2401 (pentasaccharide) mother liquor, XT2401 (pentasaccharide) solution, and GAP9805 (disaccharide) solution are all water.

[0077] In this article, the soybean variety used for the experiment is 'Zhonghuang 29' (Glycine max L.).

[0078] In this article, the peanut variety used for the experiment is 'Bianhua 7' (Arachis hypogaea L.).

[0079] In this article, the rapeseed variety used for the experiment is 'Qinsheng 800' (Brassica napus L.).

[0080] In this article, the corn variety used for the experiment is 'Jinhai 188' (Zea mays L.).

[0081] In this article, the wheat variety used for the experiment is 'Zhongmai 578' (Triticum aestivum L.).

[0082] In this article, the cucumber variety used for the experiment is 'Zaochun No. 1' (Cucumis sativus L.).

[0083] In this article, the rice variety used for the experiment is 'Nanjing 46' (Oryza sativa L.).

[0084] In this article, unless otherwise specified, the seed soaking and spraying experiments are all carried out at room temperature (25 °C).

[0085] Preparation Example

[0086]

[0087] Preparation of XT-23:

[0088] Compound XT-22 (2.3 g, 1.05 mmol), hydrazine hydrate (4 mL), and water (4 mL) were added to ethanol (90 mL), and the mixture was stirred and refluxed at 80 °C for 14 h. After the reaction was completed, the mixture was concentrated and dried. Pyridine (20 mL) and acetic anhydride (10 mL) were added, and the mixture was stirred at room temperature overnight. After the reaction was completed, the mixture was concentrated and dried. Methanol (25 mL) and sodium (60 mg) were added, and the reaction was carried out at room temperature for 12 h. After the reaction was completed, the mixture was neutralized to pH = 7 with Amberlite IR120(H + ) resin, filtered, and the solvent was evaporated. The crude product was purified by silica gel column chromatography (eluent: toluene / acetone, volume ratio 1 / 1.2) to obtain white powdery compound XT-23 (81%, three steps).

[0089] 1 1H MMR (400 MHz, CDCl3): δ 7.5 - 7.2 (m, 45H), 5.78 (d, J = 7.1 Hz, 1H), 5.18 (d, J = 7.4 Hz, 1H), 5.08 (d, J = 3.5 Hz, 1H), 5.02, 4.77 (2d, J = 10.7 Hz, 2H), 4.95, 4.59 (2d, J = 11.5 Hz, 2H), 4.91, 4.68 (2d, J = 11.8 Hz, 2H), 4.89, 4.74 (2d, J = 10.9 Hz, 2H), 4.52 - 4.41 (m, 5H), 4.29 (d, J = 7.7 Hz, 1H), 4.15 (m, 1H), 4.08 (d, J = 10.2 Hz, 1H), 3.92 (d, J = 2.6 Hz, 1H), 3.70 (m, 1H), 3.58 (s, 3H), 3.47 (dd, J = 3.6 Hz, J = 10.1 Hz, 1H), 1.40 (s, 3H), 1.14 (d, J = 8.0 Hz, 3H).

[0090] Mass spectrum (CI, NH3): m / z 1695.8 (M + NH4) + 。

[0091] Preparation of XT2401:

[0092] Compound XT-23 (1.08 g) was dissolved in methanol (45 mL), 10 wt% palladium on carbon (Pd / C, 0.2 g) was added, and the mixture was stirred at room temperature under hydrogen (150 kPa) for 12 h. After the reaction was completed, the mixture was filtered, concentrated and dried. The crude product was purified by Sephadex column chromatography (eluent: water) to obtain freeze-dried white amorphous solid XT2401 (98%).

[0093] 1H MMR(400 MHz, D2O): δ 5.02 (d, J = 4.0 Hz, 1H), 4.61 (d, J = 8.2 Hz, 1H), 4.40–4.27 (m, 3H), 4.05 (d, J = 3.3 Hz, 1H), 3.94–3.43 (m, 28H), 3.38 (d, J = 9.7 Hz, 1H), 3.25–3.17 (m, 1H), 1.92 (s, 3H), 1.07 (d, J = 6.6 Hz, 3H). Mass spectrum (ESI): m / z 890.3 (M + Na) + 。

[0094] Example 1: Seeds were soaked with a 0.1 mg / L XT2401 (pentasaccharide) solution

[0095] Multiple crop seeds with a wide planting area were selected as experimental materials (dicotyledonous varieties: soybean variety 'Zhonghuang 29', peanut variety 'Bianhua 7', rapeseed variety '560'; monocotyledonous varieties: corn variety 'Jinhai 188', wheat variety 'Zhongmai 578'). Twenty uniform seeds of soybean, peanut, and corn each, and 50 wheat seeds were selected and soaked in water or 0.1 mg / L XT2401 (pentasaccharide) for seed priming. Water or the XT2401 (pentasaccharide) solution was added to completely submerge the seeds for soaking and priming.

[0096] The phenotypic changes in water absorption and swelling of seeds of each crop were observed through experiments (Table 1, Figure 1 ) to determine the optimal soaking time for promoting germination of different crops: peanuts were soaked for 3 - 3.5 hours; corn was soaked for 6 hours; wheat was soaked for 6 hours. During the experiment, it was found that soybeans were not suitable for long-term soaking with a 0.1 mg / L XT2401 (pentasaccharide) solution. To further explore the appropriate soaking and priming time for soybeans, the soaking time was shortened to within 1 hour for the experiment, and it was observed that soaking soybeans in a 0.1 mg / L XT2401 (pentasaccharide) solution for 20 - 30 minutes was beneficial for the germination of soybean seeds. For the soaking and priming of rapeseed seeds, it was found that soaking rapeseed seeds for 8 minutes caused most seeds to start absorbing water and germinating, and a few radicles had emerged; after soaking for 15 minutes, most seeds absorbed water and germinated, and the number of germinated seeds increased; after soaking for 20 minutes and then drying, the seeds continued to germinate (see Figure 2 ). Compared with the 8-hour soaking and priming of general rapeseed seeds in water, the XT2401 (pentasaccharide) solution can germinate rapeseed seeds after soaking for 15 - 20 minutes, greatly shortening the soaking and priming time of rapeseed seeds. The appropriate soaking times for soaking and priming soybeans, peanuts, corn, wheat, and rapeseed with a 0.1 mg / L XT2401 (pentasaccharide) solution are shown in Table 2.

[0097] Table 1: Temporal phenotypic changes in the soaking and priming of XT2401 (pentasaccharide) for dicotyledonous plants (soybeans, peanuts) and monocotyledonous plants (corn, wheat)

[0098]

[0099] Table 2: Optimal soaking time for seed soaking and priming of soybean, peanut, corn, wheat and rapeseed with 0.1 mg / L XT2401 (pentasaccharide) solution

[0100]

[0101] In summary, soaking and priming with 0.1 mg / L XT2401 (pentasaccharide) can shorten the seed germination time.

[0102] Example 2: Seed soaking with different concentrations of XT2401 (pentasaccharide)

[0103] To further clarify the optimal application concentration of XT2401 (pentasaccharide) for a certain species, using wheat variety 'Zhongmai 578' as the test material, 3 seed soaking concentration gradients were set, namely the control group (water), the low concentration group (1 mg / L mother liquor diluted 15 times), and the high concentration group (1 mg / L mother liquor diluted 9 times). 5 g of seeds with uniform size and plumpness were taken and placed in a beaker, and soaked with XT2401 (pentasaccharide) solution at different concentrations, requiring that all seeds be immersed in the solution.

[0104] Phenotypic differences began to appear after 5 h of seed soaking. Clear endosperm was visible in the pentasaccharide treatment group (regardless of low or high concentration). After 7 h of seed soaking, seeds in the high concentration group began to show white tips and visible germ; seeds in the low concentration group did not break the skin and the germ was faintly visible; no germ was seen in the control group. After 7 h of seed soaking, the soaking treatment was terminated, and the seeds were placed in a dry beaker for drying back. After 21 h of drying back, almost all seeds in the high concentration group showed completely visible germ, some seeds in the low concentration group showed visible germ, and the control group seeds only swelled and no germ was seen. After 39 h of drying back, all seeds in the pentasaccharide treatment group survived. The gap in germ development between the low concentration group and the high concentration group gradually narrowed. No obvious change was seen in the control group seeds. After 63 h of drying back treatment, all seeds in the pentasaccharide treatment group survived. The germ development of seeds in the low concentration group gradually exceeded that of seeds in the high concentration group, and the germ development of seeds in the high concentration group slowed down. No obvious change was seen in the control group seeds (see Figure 3 ).

[0105] Therefore, in wheat variety 'Zhongmai 578', soaking seeds with a higher concentration of XT2401 (pentasaccharide) solution (1 mg / L mother liquor diluted 9 times) can quickly promote seed germination; soaking seeds with a lower concentration of XT2401 (pentasaccharide) solution (1 mg / L mother liquor diluted 15 times) is more conducive to the continuous germination and subsequent growth and development of wheat seeds.

[0106] Example 3: Using XT2401 (pentasaccharide) to promote seedling emergence

[0107] The mother liquor of XT2401 (pentasaccharide) at 1 mg / L was diluted 9 times to prepare a working solution, and maize, wheat, and peanut seeds were soaked for 8 h, 6 h, and 6 h respectively, and the emergence of each species in the field was observed. The test results showed that the soaking treatment with XT2401 (pentasaccharide) increased the emergence rates of maize, wheat, and peanuts (Table 3). In maize, the emergence rate increased by 24.33%; in the 2021 test of wheat seeds, the emergence rate increased by 7.35%, and in 2022, it increased by 10.78%; the emergence rate of peanuts increased by 5.96%. In addition, through the dynamic monitoring of the emergence process of wheat seeds in the field, it was found that the XT2401 (pentasaccharide) treatment group was superior to the control group (soaked with water) in terms of emergence rate, emergence rate, and seedling growth Figure 4 ).

[0108] Table 3 ： Soaking seeds with XT2401 (pentasaccharide) increases the emergence rates of maize, wheat, and peanuts

[0109]

[0110] Example 4: Using XT2401 (pentasaccharide) to increase yield

[0111] Tests on the effects of XT2401 (pentasaccharide) on the yields of different crops (maize, wheat, rice, rapeseed, peanuts, and cucumbers) were carried out in different regions (Shanghai, Henan) and different years (2020 - 2023). The XT2401 (pentasaccharide) intervention was divided into 2 treatment methods: (1) soaking + spraying: The mother liquor at 0.001 cubic meters and 1 mg / L was diluted 9 times to prepare a soaking working solution for soaking treatment (the corresponding soaking duration is shown in Table 4 below). After the treatment, the recovered solution was further diluted 200 times to prepare a spraying working solution, which was used for spraying on the above-ground parts of seedlings and plants in the later growth stage. The spraying was carried out until water droplets dropped evenly on both the front and back sides of the leaves; (2) spraying: The mother liquor at 0.001 cubic meters and 1 mg / L was directly diluted 1800 times and sprayed on the above-ground parts of the plants without soaking treatment. The control group was treated with water soaking for 6 hours. The results showed that the XT2401 (pentasaccharide) treatment group could increase the yields of maize, wheat, rice, rapeseed, peanuts, and cucumbers (Table 4). Among them, the yields of maize, wheat, rice, peanuts, and rapeseed refer to the yields of seeds, and the yield of cucumbers refers to the yield of fruits. The percentage of yield increase ranges from 10% to 52.34%.

[0112] Taking the food crop corn as an example, compared with the control group, the corn plants in the experimental group treated with XT2401 (pentasaccharide) solution were insensitive to changes in soil pH, temperature, and humidity, showed strong tolerance to extreme environmental stresses, and had a low probability of diseases and pests. In terms of growth rate, the experimental group flowered and fruited earlier than the control group, and the growth period was shortened by one-third to one-half. In terms of yield, most plants in the control group had a single ear per plant, and a few had two ears, while most plants in the experimental group had two or three ears per plant, and the total fruit-setting rate increased by 2 times. In terms of the taste of the product quality, the experimental group was sweeter and more glutinous, and was liked by consumers.

[0113] Table 4: Yield-increasing effects of XT2401 on species such as corn, wheat, rice, rape, peanut, and cucumber

[0114]

[0115] Example 5: Using XT2401 (pentasaccharide) to promote wound repair

[0116] The diseased cucumber leaves were cut off, and the cut parts were sprayed with a 1000-fold solution of XT2401 (diluted 1000 times from a 1 mg / L mother solution), and 0.01 mL was sprayed on each cut part. The control group was sprayed with the same volume of water. Compared with the control, new leaves grew on the diseased parts sprayed with pentasaccharide within 24 h (after supplementary lighting), and subsequent growth mainly consisted of female flowers and their fruits (see Figure 5 ). The control group could not grow new leaves and did not flower. Therefore, spraying pentasaccharide on plants can quickly repair the damaged parts.

[0117] Example 6: Using XT2401 (pentasaccharide) to improve the response to stress

[0118] Cucumbers growing in saline-alkali soil were treated with XT2401. The treatment method for the XT2401 treatment group was (1) seed soaking (concentration 1 mg / L, time 6 hours) + spraying (0.01 mg / L, volume 0.001 cubic meters); (2) seed soaking (concentration 1 mg / L, time 6 hours). The control group was only soaked with the same volume of water and sprayed with the same volume of water. It was found that the XT2401 treatment group was significantly superior to the control group in terms of emergence rate and growth vigor under saline-alkali stress ( Figure 6 ); and the group with XT2401 seed soaking plus spraying could quickly promote emergence and subsequent growth and development, indicating that XT2401 has the ability to improve the resistance of cucumbers to saline-alkali stress.

[0119] Example 7: Comparison of product effects of XT2401 (pentasaccharide) and GAP9805 (disaccharide)

[0120]

[0121] Using the cucumber variety 'Early Spring No. 1' as the test material, seeds were treated with water (control group), XT2401 (pentasaccharide), and GAP9805 (disaccharide) solutions, with 30 seeds in each group. The XT2401 (pentasaccharide) and GAP9805 (disaccharide) soaking solutions were working solutions prepared by diluting the 1 mg / L stock solution 10 times. After soaking for 7 h and then drying back for 30 min, the XT2401 (pentasaccharide) and GAP9805 (disaccharide) treatment groups showed obvious signs of germination compared to the control group. After soaking for 24 h and drying back for 30 min, the germination rate of the control group was 13.33%, the germination rate of the GAP9805 (disaccharide) treatment group reached 56.67%, while all the seeds in the XT2401 (pentasaccharide) group germinated. The results showed (Table 5, Figure 7 ), both XT2401 (pentasaccharide) and GAP9805 (disaccharide) could promote cucumber seed germination, and the effect of XT2401 (pentasaccharide) was better.

[0122] Table 5: Differences in the priming effects of XT2401 (pentasaccharide) and GAP9805 (disaccharide) products on cucumber seeds

[0123] Processing time Control group XT2401 (pentasaccharide) GAP9805 (disaccharide) Soaking seeds for 7 h + drying back for 30 min No obvious change was seen There were obvious germination signs There were obvious germination signs Soaking seeds for 24 h + drying back for 30 min The germination rate was 13.33% The germination rate reached 100% The germination rate was 56.67%

[0124] In addition, using rice 'Nanjing 46' as the test material, after soaking in XT2401 (pentasaccharide) and GAP9805 (disaccharide) solutions (working solutions prepared by diluting the 1 mg / L stock solution 10 times) for 24 h and then drying back for 30 min, it was found that XT2401 (pentasaccharide) and GAP9805 (disaccharide) treatments caused most seeds to germinate. When exposed to low temperature for 5 days (March 17 - 21, 2023) (the test was carried out at a low temperature of ≤15°C, and the temperature is shown in Table 6 below), the XT2401 (pentasaccharide) treatment group had a better effect than the GAP9805 (disaccharide) treatment group.

[0125] Table 6: Maximum and minimum temperatures from March 17 to 21, 2023 during the test

[0126] Time Highest temperature (°C) Lowest temperature (°C) March 17, 2023 9 7 March 18, 2023 11 7 March 19, 2023 12 9 March 20, 2023 14 12 March 21, 2023 15 13

[0127] Similarly, in rapeseed, XT2401 (pentasaccharide) and GAP9805 (disaccharide) diluted 10 times from the 1 mg / L stock solution were used to prime rapeseed seeds. After soaking for 20 min and drying back for 2 h, it was found that the seeds in the XT2401 (pentasaccharide) and GAP9805 (disaccharide) treatment groups had obvious signs of germination, and the effect of XT2401 (pentasaccharide) in promoting germination was better than that of GAP9805 (disaccharide).

[0128] Example 8

[0129] Control group: Corn seeds were not treated with XT2401 (pentasaccharide). The seeds were sown for seedling raising and transplanted into a soil plot with a pH of 5.6 at the same time as the experimental group. During this period, no fertilizers and pesticides were used. New leaves grew 12 days after transplantation, the ears emerged 65 days later, and the ears matured and were harvested 130 days later. 95% of the plants had single ears, 5% of the plants had double ears, and 28% of the plants showed varying degrees of withering and disease conditions.

[0130] Experimental group: Corn seeds were soaked in XT2401 (pentasaccharide) at a concentration of 0.1 mg / L for 8 hours and then evenly sown in the same plot as the control group. During this period, no other fertilizers and pesticides were used. The seeds germinated 4 days after sowing, new leaves grew 8 days later, the ears emerged 45 days later, and the ears matured and were harvested 79 days later. 90% of the plants in this group had double ears, 10% of the plants had triple ears, and there were no withering and disease conditions.

Claims

1. A plant immune regulator having the structure shown in Formula I: In Formula I, R1 is selected from H, R3-C(O)-; R2 is selected from H, C1-C6 alkyl; R3 is selected from H, C1-C6 alkyl and C6-C14 aryl.

2. The plant immune regulator according to claim 1, characterized in that: R1 is selected from H, H-C(O)-, C1-C4 alkyl-C(O)- and C6-C10 aryl-C(O)-; preferably, R1 is selected from H-C(O)-, C1-C2 alkyl-C(O)- and C6-C10 aryl-C(O)-; and / or, R2 is C1-C4 alkyl.

3. The plant immune regulator according to claim 1, characterized in that, The plant immune regulator has the structure shown in XT2401:

4. A pesticidal composition, characterized in that, The pesticide composition comprises the plant immune regulator according to any one of claims 1-3 and a pharmaceutically acceptable carrier.

5. The pesticidal composition according to claim 4, wherein The pesticide composition further comprises other pesticides and / or fertilizers; preferably, the other pesticide is a plant growth regulator.

6. Use of the plant immune regulator according to any one of claims 1-3, and the pesticide composition according to claim 4 or 5 in regulating plant growth, development, reproduction, disease prevention and / or disease resistance.

7. The application according to claim 6, characterized in that, The plant is selected from one or more of soybean, peanut, rapeseed, corn, wheat, cucumber and rice; and / or, the regulation of plant growth, development, reproduction, disease prevention and / or disease resistance includes: promoting seed germination, promoting seedling morphogenesis, promoting the growth of plants in the adult stage, promoting plant injury repair, increasing crop yield, improving fruit quality, enhancing the resistance of plants to biotic stress, and enhancing the resistance of plants to abiotic stress.

8. The application according to claim 7, characterized in that The biotic stress includes one or more of diseases, pests and weeds; and / or, the abiotic stress includes one or more of drought, waterlogging, salinity, extreme low temperature and extreme high temperature, preferably, the extreme low temperature is ≤15°C and the extreme high temperature is ≥30°C.

9. The application according to any one of claims 6 - 8, characterized in that, The use is selected from the following group: (1) Use of the plant immune regulator according to any one of claims 1-3, and the pesticide composition according to claim 4 or 5 in promoting the germination of plant seeds; (2) Use of the plant immune regulator according to any one of claims 1-3, and the pesticide composition according to claim 4 or 5 in promoting the emergence of plant seeds; (3) Use of the plant immune regulator according to any one of claims 1-3, and the pesticide composition according to claim 4 or 5 in increasing plant yield; (4) Use of the plant immune regulator according to any one of claims 1-3, and the pesticide composition according to claim 4 or 5 in promoting plant injury repair; (5) Use of the plant immune regulator according to any one of claims 1-3, and the pesticide composition according to claim 4 or 5 in enhancing the response of plants to stress.

10. A method for regulating plant growth, development, reproduction, disease prevention and / or disease resistance, characterized in that, The method includes applying the plant immune regulator according to any one of claims 1-3 or the pesticide composition according to claim 4 or 5 to the plant; preferably, the application includes seed soaking and / or spraying.

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