Lecanicillium lecanii and use thereof

Abstract

The application provides a Lecanicillium attenuatum strain and application thereof, the classification and name of the strain are LIO314, which has been preserved in the China Center for Type Culture Collection on June 18, 2025. Lecanicillium aphanocladii The address for preservation is Wuhan University, Wuhan, China, and the preservation number is CCTCC NO: M 20251419. Research shows that the strain exhibits significant inhibitory effect on plant pathogenic fungi such as Fusarium graminearum and Colletotrichum gloeosporoides, can efficiently kill pepper aphids, has nitrogen fixation, potassium and starch decomposition activities, can significantly promote the growth of rice, wheat and lettuce seedlings, can be used as an efficient, environment-friendly and low-cost biological control agent, simultaneously has plant growth regulation function, can be used as a biological bacteria organic fertilizer, and has wide development and utilization value and application prospect in agricultural production.

Description

Technical Field

[0001] This invention relates to the field of agricultural microbiology, and more specifically, to a strain of *Heterocystis suis* and its applications. Background Technology

[0002] Plant endophytes are microorganisms that live inside plants at some or all stages of their life cycle without causing significant infection. They include endophytic bacteria, endophytic fungi, and endophytic actinomycetes. Endophytic fungi exist in everything from lower algae, bryophytes, and ferns to higher gymnosperms and angiosperms. Endophytic fungi inhabit the plant and co-evolve with their host plants, forming the oldest and most widespread mutualistic symbiotic relationship in plant ecosystems. Plants can utilize endophytes to promote their own growth while also protecting themselves from external environmental factors and pests. (Example: Wax scale fungus...) Lecanicillium spp. Entomogenic fungi (Eutrophomonas) are a class of entomopathogenic fungi with a wide host range. They can exist as entomopathogenic fungi and also transform into plant endophytes. Eutrophomonas widely parasitize important agricultural pests such as thrips and whiteflies, making them a research hotspot in the field of biological control. Eutrophomonas were also one of the first commercially available entomopathogenic fungi, and they can be used not only to control insects and nematodes but also to inhibit various plant pathogenic fungi such as powdery mildew, rust, and green mold.

[0003] Chinese invention patent CN120173757A discloses a type of *Cyclocarya paliurus*, its inoculant, and its application. This *Cyclocarya paliurus* (… Lecanicillium aphanocladill GC-2 strain has been verified to have strong inhibitory activity against wheat stripe rust, Fusarium graminearum, and Fusarium pseudograminearum. Pot experiments have demonstrated that this strain has a very strong inhibitory effect on the urediniospores of wheat stripe rust and a strong antagonistic effect on the pathogens of wheat scab and wheat stem rot. This strain shows significant control effects against wheat stripe rust, wheat stem rot, and wheat scab. Therefore, developing more wax scale fungi with special biological control functions for agricultural applications to enrich biological control methods and improve crop production has potential application value. Summary of the Invention

[0004] The purpose of this invention is to solve the above-mentioned technical problems and provide a strain of *Cercospora filamentosa*. Another purpose of this invention is to provide an application in promoting plant growth and development.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This invention provides a strain of *Cercospora filamentosa*, classified and named as follows: Lecanicillium aphanocladiiLI0314 was deposited on June 18, 2025 at the China Center for Type Culture Collection (CCTCC), Wuhan University, Wuhan, China, with accession number CCTCC NO: M 20251419.

[0007] This invention screened a strain of *Cercospora filamentosa* from the aboveground parts of the highly resistant white rust cut chrysanthemum variety 'Rosie Champagne'. Research revealed that this strain differs from *Cercospora filamentosa* GZUIFR.SP477, representing a novel strain. Furthermore, this strain exhibits unique properties, such as resistance to *Fusarium graminearum* (…). Fusarium graminearum ) and Discoidys spores ( Colletotrichum gloeosporioides It has a significant inhibitory effect on plant pathogens such as pepper aphids, and can effectively kill pepper aphids. It also has nitrogen-fixing, potassium-solubilizing and starch-solubilizing activities, and can significantly promote the growth of seedlings of rice, wheat and lettuce. It can be used as a highly efficient, environmentally friendly and low-cost biological control agent. At the same time, it also has plant growth regulation functions and can be used as a biological organic fertilizer. It has broad development and utilization value and application prospects in agricultural production.

[0008] This invention provides the application of the above-mentioned *Cercospora filamentosa* in promoting plant growth and development.

[0009] Furthermore, the plant is rice, wheat, or glass lettuce.

[0010] Furthermore, the growth and development refers to increasing the root length and / or root weight, and the bud length and / or bud weight of the seedling after seed germination.

[0011] This invention provides a biological agent for promoting plant growth, comprising the above-mentioned *Cercospora filamentosa*.

[0012] This invention provides the application of the above-mentioned *Cercospora filamentosa* as a plant endophyte in the production of plant-absorbable nitrogen fertilizer, potassium fertilizer, and / or starch degradation.

[0013] This invention provides the above-mentioned *Cercospora filamentosa* in inhibiting *Discospora discospora* (… Colletotrichum gloeosporioides ) and / or Fusarium graminearum ( Fusarium graminearum Applications during growth.

[0014] This invention provides the above-mentioned *Cercospora filamentosa* for killing pepper aphids (… Myzus persicae Applications in ).

[0015] This invention provides a biological control agent comprising the aforementioned *Cercospora filamentosa*, which can inhibit *Colletotrichum discoidosa* (…). Colletotrichum gloeosporioides Fusarium graminearum ( ), Fusarium graminearum ) or pepper aphids ( Myzus persicae(or to prevent and control plant diseases caused by the aforementioned Colletotrichum, Fusarium graminearum, or pepper aphid.)

[0016] This invention provides a bio-organic fertilizer containing the aforementioned *Cercospora filamentosa*; the bio-organic fertilizer, as plant endophytic bacteria, generates plant-absorbable nitrogen fertilizer, potassium fertilizer, and / or degrades starch.

[0017] The beneficial effects of this invention are as follows:

[0018] This invention screened a strain of *Cercospora filamentosa* from the aboveground parts of the highly resistant white rust cut chrysanthemum variety 'Rosie Champagne'. Research revealed that this is a novel strain of *Cercospora filamentosa* GZUIFR.SP477, distinct from existing strains, and exhibits unique properties, such as resistance to *Fusarium graminearum*. Fusarium graminearum ) and Discoidys spores ( Colletotrichum gloeosporioides It has a significant inhibitory effect on plant pathogens such as pepper aphids, and can effectively kill pepper aphids. It also has nitrogen-fixing, potassium-solubilizing and starch-solubilizing activities, and can significantly promote the growth of seedlings of rice, wheat and lettuce. It can be used as a highly efficient, environmentally friendly and low-cost biological control agent. At the same time, it also has plant growth regulation functions and can be used as a biological organic fertilizer. It has broad development and utilization value and application prospects in agricultural production.

[0019] This strain of *Heterocystis suis* is classified as... Lecanicillium aphanocladii LI0314, also known as *Cyclocarya spp.*, was deposited at the China Center for Type Culture Collection (CCTCC) on June 18, 2025. The deposit address is: Wuhan University, Wuhan, China, and the accession number is: CCTCC NO: M 20251419. Attached Figure Description

[0020] Figure 1 This is a colony characteristic diagram of *Heterobacter filamentosa* LI0314;

[0021] In the diagram, A represents the front view of the colony; B represents the back view of the colony.

[0022] Figure 2 This is the sporulation structure of *Heterocystis li0314*.

[0023] In the figure, A and B represent the sporulation structures of *Leptochloa crus-galli* LI0314 under different fields of view.

[0024] Figure 3 This is a phylogenetic analysis phylogenetic tree of *Heterobacter filamentosa* LI0314.

[0025] Figure 4 This shows the growth of pathogens in the fermentation broth group and the control group;

[0026] A: Verticillium dahliae ; B: Fusarium graminearum ; C: Verticillium dahliae ; D: Fusarium graminearum.

[0027] Figure 5 is the aphid immersed by Lecanicillium lecanii LI0314;

[0028] A: the aphid immersed by Lecanicillium lecanii LI0314 for 7 days; B: the aphid immersed by Lecanicillium lecanii LI0314 for 14 days.

[0029] Figure 6 is the nitrogen fixation activity detection of Lecanicillium lecanii LI0314;

[0030] A: the growth of Lecanicillium lecanii LI0314 cultured for 5 days after 6 times of transfer on nitrogen-free medium; B: the growth of Lecanicillium lecanii LI0314 cultured for 14 days after 6 times of transfer on nitrogen-free medium.

[0031] Figure 7 is the potassium solubilization ability detection of Lecanicillium lecanii LI0314;

[0032] A: the front view of Lecanicillium lecanii LI0314 colony; B: the back view of Lecanicillium lecanii LI0314 colony.

[0033] Figure 8 is the amylase activity detection of Lecanicillium lecanii LI0314.

[0034] Figure 9 is the effect of Lecanicillium lecanii LI0314 fermentation broth on rice growth.

[0035] Figure 10 is the effect of Lecanicillium lecanii LI0314 fermentation broth on wheat growth.

[0036] Figure 11 is the effect of Lecanicillium lecanii LI0314 fermentation broth on glass lettuce growth. DETAILED DESCRIPTION

[0037] In order to make the person skilled in the art better understand the technical scheme of the present application, the technical scheme in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by the person skilled in the art without creative labor should belong to the protection scope of the present application.

[0038] Example 1 Strain isolation, screening, physiological and biochemical identification and preservation

[0039] 1. Test method

[0040] (1) Isolation and purification of strains

[0041] Fresh and healthy high white rust resistant cut chrysanthemum variety "Rosixiangbeng" was collected from the chrysanthemum base of Suzhou Institute of Technology in Changshu City, Suzhou City, Jiangsu Province. The aboveground parts were carefully collected and stored at 4°C in the laboratory. All subsequent experiments were performed within 2 hours of collection to ensure sample freshness and reliability. The chrysanthemum leaves were removed and the stems were cut into 2 cm long sections. The chrysanthemum stem sections were first soaked in a solution containing dishwashing liquid for 5 minutes, then washed with running water for 30 minutes and dried. The stem sections were then surface sterilized in a clean bench. After surface sterilization, the stem sections were first soaked in 75% ethanol for about 45 seconds, then rinsed with sterile water three times, then rinsed with 5% sodium hypochlorite for two minutes, then rinsed with sterile water four times, then dried the surface of the stem sections with sterile filter paper, then cut the stem longitudinally with a sterile scalpel, and placed it on potato dextrose agar medium (PDA solid medium) so that the cross section was in full contact with the PDA solid medium. It was placed in a 28°C constant temperature incubator and cultured in the dark for 2-10 days. After the colonies grew on the PDA solid medium, the edge of the colony was picked with a sterile needle and transferred to a new PDA solid medium. After single hypha isolation and purification, it was transferred to PDA solid medium and cultured at 28°C.

[0042] (2) Observation of colony characteristics of strains

[0043] The strain was transferred to a PDA plate and cultured in a 28°C incubator in the dark for 14 days. The color of the colony, the morphology of the mycelium, and other characteristics were recorded and observed. The sterile cover glass was inserted obliquely into the middle of the PDA plate at 28°C and cultured in the dark. When a small amount of mycelium grew on the cover glass, the characteristics of the strain such as conidia and conidiophores were observed, recorded and measured under a microscope.

[0044] (3) Molecular biology identification of strains

[0045] The strain cultured on PDA medium for 5 days was sent to the company for sequencing. The sequencing results were compared with the homology in the NCBI database, and a phylogenetic tree was constructed.

[0046] 2. Test results

[0047] (1) A strain was isolated and purified, and its colony characteristics are shown in Figure 1 . The strain grew on PDA medium, and the colony front view was round, white, and the mycelium grew radially, as shown in Figure 1 A. The colony back was purple red, as shown in Figure 1 B, producing a purple red pigment; the mycelium had a diaphragm. The sporulation structure of the strain is shown in Figure 2 , which is composed of Figure 2 A and Figure 2The sporulation structure of *Hylocereus filophyte* LI0314 under different fields of view (B) shows that conidiophores grow directly from the hyphae, occurring singly, oppositely, or whorled, with singly being the most common. The conidiophores are relatively long and gradually taper upwards, forming phialides. Conidia are singly elliptical. Chlamydospores are visible. The strain is identified as *Hylocereus filophyte* LI0314.

[0048] (2) The sequencing results of strain *Streptococcus filamentosa* LI0314, including its 18S rRNA sequence as shown in SEQ ID NO.1, were analyzed for homology in the NCBI database to construct a phylogenetic tree based on the full 18S rRNA sequence. Figure 3 As shown, based on phylogenetic relationships, *Cyclocarya spp.* LI0314 (referred to as LI0314.ab1 in clustering) and *Cyclocarya spp.* Lecanicillium aphanocladii Based on the observation of the clustered bacteria and their morphological characteristics, the strain used in this invention was ultimately identified as *Hemiberlesia lataniae*, and classified and named accordingly. Lecanicillium aphanocladii LI0314. LI0314 and *Gymnocladus spp.* GZUIFR.SP477 cluster in a subbranch, but their morphology, conidiophore attachment, and host differ significantly. *Gymnocladus spp.* GZUIFR.SP477 was isolated from wheat field soil samples in Lazi County, Shigatse City, Tibet Autonomous Region. Colonies grown on PDA medium have a red underside, with most conidiophores borne in groups of 2-3 on the mycelium. LI0314, on the other hand, was isolated from Rossi Champagne cut chrysanthemums highly resistant to white rust. Colonies grown on PDA medium have a purplish-red underside, with conidiophores predominantly solitary. Therefore, LI0314 and *Gymnocladus spp.* GZUIFR.SP477 are two different species.

[0049] (3) Preservation of microbial strains

[0050] Ficus pumila Lecanicillium aphanocladii LI0314 was cultured until sporulation (which can be determined by color change). Holes were punched in the culture medium, and the resulting mycelial cakes were inoculated into cryovials containing 50% glycerol. The cells were first placed at 4°C for 20 minutes to acclimate, then at -20°C for 0.5 hours, and finally at -80°C for long-term storage. The preserved strains were checked regularly; generally, one strain was taken out every 6-12 months for resuscitation culture to observe any changes in growth and characteristics.

[0051] When removing the storage tube from the freezer, it should be quickly placed in a warm water bath at around 37°C to thaw rapidly, in order to reduce the damage of ice crystals to the cells. Then, the mycelium cake should be removed and transferred to a fresh culture medium.

[0052] This strain of *Heterocystis jirovecii* is classified and named as follows: Lecanicillium aphanocladiiLI0314, which has been preserved in China Center for Type Culture Collection (CCTCC) on June 18, 2025. The preservation address is: Wuhan, China. Wuhan University, and the preservation number is: CCTCC NO: M 20251419; the viability of the culture was tested in China Center for Type Culture Collection on June 25, 2025, and the result was viable.

[0053] Example 2 Study on the antibacterial activity of Ampelomyces quisqualis LI0314

[0054] 1. Test method

[0055] The endophytic fungus fermentation broth of Ampelomyces quisqualis LI0314 was prepared, and after filtration and sterilization, the endophytic fungus fermentation broth was used to detect the antagonistic effect of Ampelomyces quisqualis LI0314 on plant pathogenic fungi represented by Fusarium graminearum and Physalospora longipes; the control group of pathogenic fungi was Physalospora longipes and Fusarium graminearum; the experimental group was PDA medium added with 30% fermentation broth and inoculated with Physalospora longipes and Fusarium graminearum, respectively.

[0056] Preparation of endophytic fungus fermentation broth: In a clean bench, a puncher with a diameter of 5 mm was used to punch the colony edge of the purified and well-grown active strain, and 5 pieces of the above-mentioned fungus cake were inoculated into 200 mL PDB medium and cultured at 28°C on a shaker at 160 rpm for 5 days. The fermentation broth was filtered and sterilized through a 0.22 µm sterile filter membrane, and the filtrate was collected, which was the sterile fermentation product.

[0057] 2. Test results

[0058] The test results are shown in Table 1. Figure 4 Figure 4 Table 1: Test results Figure 4 A represents Physalospora longipes (control group of pathogenic fungi); Figure 4 B represents Fusarium graminearum (control group of pathogenic fungi); Figure 4 C represents Physalospora longipes (inhibition of pathogenic fungi by Ampelomyces quisqualis LI0314 filtered and sterilized fermentation broth); Figure 4 D represents Fusarium graminearum (inhibition of pathogenic fungi by Ampelomyces quisqualis LI0314 filtered and sterilized fermentation broth). Colletotrichum gloeosporioides The results show that Ampelomyces quisqualis LI0314 has strong inhibition on Physalospora longipes ( Fusarium graminearum ) and Fusarium graminearum ( ). The addition of 30% fermentation broth in the culture medium has an inhibition rate of 43.8% on Physalospora longipes and an inhibition rate of 93.8% on Fusarium graminearum. Compared with the same strain Ampelomyces quisqualis GZUIFR.SP477, it does not have this property.

[0059] Example 3: Pathogenicity determination of *Bacillus filamentosa* LI0314 against pepper aphids.

[0060] 1. Test Methods

[0061] The method of dipping insects to kill pepper aphids ( Myzus persicae Pathogenicity was determined. *Cercospora filamentosa* LI0314 was inoculated onto PDA solid medium and incubated in the dark at 28°C for 14 days. Conidia of *Cercospora filamentosa* LI0314 were then washed with a sterile aqueous solution containing 0.05% Tween 80. The vortexed conidia were then filtered through double-layered sterile lens paper. The concentration of the spore suspension was determined using a hemocytometer, and the concentration was adjusted to 5 × 10⁻⁶. 8 Approximately [number] insects / mL. Wingless adult aphids were picked up with the tip of a brush and immersed in the spore suspension for 5 seconds, then removed. After the liquid on the insect's surface air-dried naturally, they were transferred to fresh chili leaves (with a cotton ball at the petiole kept moist) and placed in clean glass petri dishes. These dishes were then reared in a light incubator at 25°C with a photoperiod of 16 h light / 8 h dark and a relative humidity of 65%. Each treatment contained 30 insects, with a sterile aqueous solution containing 0.05% Tween 80 as a control, and three biological replicates were performed. Symptoms of infection were observed daily, and the number of dead insects was recorded. Dead insects were then cultured in a moist environment, and the growth of mycelium on the insect's surface was observed to determine whether the death was caused by fungal infection.

[0062] 2. Test Results

[0063] Pepper aphids began to die after day 3 of the experiment, and the mortality rate reached 75% by day 7. Figure 5 China A and Figure 5 As shown in Figure B, the body surface of the dead aphids was covered with fluffy filamentous material. Tissue samples from the dead individuals suspected of containing fungal hyphae were cultured, isolated, and identified using molecular biology techniques. The fluffy filamentous material on the body surface of the dead aphids was confirmed to be *Hymenococcus filamentosa* LI0314; this property was not present in the same strain, *Hymenococcus filamentosa* GZUIFR.SP477.

[0064] Example 4: The life-promoting properties and applications of *Firmiana simplex* LI0314

[0065] 1. Test Methods

[0066] (1) Nitrogen fixation capacity of *Bacillus filamentosa* LI0314

[0067] Nitrogen plays an important role in the process of plant growth. Endophytic fungi with nitrogen fixation activity can promote the growth of plant roots, promote the uptake and utilization of nutrients by plants, and improve the plant's resistance to adverse environments, with good growth-promoting activity. The ability to grow normally on nitrogen-free medium indicates that the endophytic fungus has nitrogen fixation activity. The fungus cake (d = 0.5 cm) of Lecanicillium tenellum LI0314 was inoculated in nitrogen-free medium, and the fungus was cultured in a constant temperature incubator at 28°C. It was observed whether the endophytic fungus could grow normally in the medium. If it could, it indicated that the strain had nitrogen fixation activity. On this basis, if a transparent circle was produced, it indicated that the strain had strong nitrogen fixation activity.

[0068] (2) Potassium solubilizing ability of Lecanicillium tenellum LI0314

[0069] Potassium is one of the essential nutrients for plant growth and development. Endophytic fungi with potassium solubilizing ability can secrete organic acids (such as citric acid, oxalic acid) to reduce the environmental pH, dissolve potassium in minerals such as mica and feldspar, and convert soil ineffective potassium into available potassium that can be absorbed by plants. The fungus cake (d = 0.5 cm) of Lecanicillium tenellum LI0314 was inoculated in potassium solubilizing ability detection medium, and the fungus was cultured in a constant temperature incubator at 28°C. It was observed whether the endophytic fungus could produce a transparent circle on the medium.

[0070] (3) Amylolytic ability of Lecanicillium tenellum LI0314

[0071] Endophytic fungi with amylolytic ability can secrete extracellular enzymes such as α-amylase and β-amylase to decompose starch into small molecule carbon sources such as glucose, providing energy for their own colonization, and significantly promoting growth through improving plant carbon metabolism and enhancing root activity. The fungus cake (d = 0.5 cm) of Lecanicillium tenellum LI0314 was inoculated in amylolytic ability detection medium, and the fungus was cultured in a constant temperature incubator at 28°C. After that, iodine solution was added to the medium for staining. It was observed whether there was a transparent circle. If there was, it indicated that the strain had amylase activity. The larger the transparent circle, the stronger the amylase production ability.

[0072] 2. Test results

[0073] (1) Lecanicillium tenellum LI0314 grew normally on nitrogen-free medium as shown in Figure 6 . The growth of Lecanicillium tenellum LI0314 cultured for 5 days after being transferred to nitrogen-free medium for 6 times is shown in Figure 6 A, and the growth after being cultured for 14 days is shown in Figure 6 B. There was a clear transparent circle around the colony, indicating that Lecanicillium tenellum LI0314 had strong nitrogen fixation activity.

[0074] (2) The potassium solubilizing ability of Lecanicillium tenellum LI0314 is shown in Figure 7 , combined with Figure 7 A and Figure 7 B, it can be seen that there is a clear transparent circle around the colony, indicating that Lecanicillium longisporum LI0314 has obvious potassium- releasing ability.

[0075] (3) The ability of Lecanicillium longisporum LI0314 to release starch is shown in Figure 8 Fig. 6, and there is a clear transparent circle around the colony, indicating that Lecanicillium longisporum LI0314 has very strong starch- releasing ability. In comparison, the same strain Lecanicillium longisporum GZUIFR.SP477 does not have this property. Figure 8

[0076] Example 5 Promoting effect of Lecanicillium longisporum LI0314 on plant growth

[0077] 1. Test method

[0078] (1) Effect of Lecanicillium longisporum LI0314 fermentation broth on rice growth

[0079] Lecanicillium longisporum LI0314 was activated on PDA solid medium for 5 days, 0.5 cm x 0.5 cm fungus cake was inoculated into PDB liquid medium, and placed in a shaking bed at 150 rpm and 28°C for 5 days, and then centrifuged at 6000 rpm for 10 min, and the supernatant was collected, which was Lecanicillium longisporum LI0314 fermentation broth. The sterilized rice seeds were soaked in 70% Lecanicillium longisporum LI0314 fermentation broth for 24 hours, then placed in a culture dish containing sterilized filter paper, and germinated in a 25°C constant temperature incubator, with PDB liquid medium as a control. Each treatment had 34 seeds, and 5 replicates. During the germination process, the cover was opened for ventilation at regular intervals and the humidity of the filter paper was maintained at all times. The root length was recorded daily for 7 days.

[0080] (2) Effect of Lecanicillium longisporum LI0314 fermentation broth on wheat growth

[0081] The sterilized wheat seeds were soaked in 70% Lecanicillium longisporum LI0314 fermentation broth for 24 hours, then placed in a culture dish containing sterilized filter paper, and germinated in a 25°C constant temperature incubator, with PDB liquid medium as a control. Each treatment had 25 seeds, and 3 replicates. During the germination process, the cover was opened for ventilation at regular intervals and the humidity of the filter paper was maintained at all times. The root length was recorded daily for 5 days.

[0082] (3) Effect of Lecanicillium longisporum LI0314 fermentation broth on glass lettuce growth

[0083] ​Sterilized glass lettuce seeds were soaked in 70% fermentation broth of *Mycobacterium cladoides* LI0314 for 24 hours, then placed in petri dishes containing sterilized filter paper and incubated at 25°C. Seeds soaked in PDB liquid medium served as a control. Each treatment consisted of 30 seeds, with three replicates. During germination, the lid was opened periodically for ventilation, and the filter paper was kept consistently moist. Root length was recorded daily for 4 days.

[0084] 2. Test Results

[0085] (1) Effects of fermentation broth of *Bacillus cereus* LI0314 on rice growth, such as Figure 9 As shown, on day 7 of rice germination, the average root length of the control group was 4.327 cm, the average shoot length was 3.598 cm, the average root weight was 0.0112 g, and the average shoot weight was 0.0145 g. The average root length of the experimental group was 5.491 cm, an increase of 27% compared to the control group; the average shoot length was 3.933 cm, an increase of 9% compared to the control group; the average root weight was 0.0141 g, an increase of 26% compared to the control group; and the average shoot weight was 0.0170 g, an increase of 17% compared to the control group. Therefore, *Streptococcus filamentosa* LI0314 has a significant growth-promoting effect on rice seeds.

[0086] (2) The effect of fermentation broth of *Bacillus cereus* LI0314 on wheat growth, as follows: Figure 10 As shown, on day 5 of wheat germination, the control group had an average root length of 7.8 cm, an average shoot length of 8.9 cm, an average root weight of 0.0429 g, and an average shoot weight of 0.0574 g. The experimental group had an average root length of 8.9 cm, an increase of 14% compared to the control group; an average shoot length of 9.6 cm, an increase of 7% compared to the control group; an average root weight of 0.0512 g, an increase of 19% compared to the control group; and an average shoot weight of 0.0668 g, an increase of 16% compared to the control group. Therefore, the fermentation broth of *Mycorrhiza li0314* has a significant growth-promoting effect on wheat seeds.

[0087] (3) The effect of fermentation broth of *Bacillus cereus* LI0314 on the growth of glass lettuce, as shown in the figure. Figure 11 As shown, on day 4 of germination of glass lettuce, the control group had an average root length of 2.1 cm, an average shoot length of 2.2 cm, an average root weight of 0.0044 g, and an average shoot weight of 0.0086 g. The experimental group had an average root length of 2.7 cm, an increase of 28% compared to the control group; an average shoot length of 2.6 cm, an increase of 18% compared to the control group; an average root weight of 0.0056 g, an increase of 27% compared to the control group; and an average shoot weight of 0.0108 g, an increase of 25% compared to the control group. Therefore, *Mycorrhiza li0314* has a growth-promoting effect on glass lettuce seeds. This property is not present in the *Mycorrhiza li0314* strain GZUIFR.SP477.

[0088] Meanwhile, the seed growth promoting effect of the V. lecanii LI0314 has significant differences for different species and their germination and root growth, wherein the root and shoot growth for the crops rice and wheat is obviously lower than the vegetable glass lettuce, and the root length and root weight promoting effect for the crops rice and wheat is significantly better than the shoot length and shoot weight.

[0089] Finally, it should be pointed out that the above examples are only used to illustrate the technical solutions of the present application and not to limit the solutions. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or equivalently replaced on the basis of understanding the solutions without departing from the purpose and scope of the technical solutions of the present application, and they should be covered in the scope of the claims of the present application.

Claims

1. A strain of *Cyclocarya spp.*, characterized in that, Category naming Lecanicillium aphanocladii LI0314 was deposited on June 18, 2025 at the China Center for Type Culture Collection (CCTCC), Wuhan University, Wuhan, China, with accession number CCTCC NO: M 20251419.

2. The application of the *Cercospora filamentosa* as described in claim 1 in promoting plant growth and development.

3. The application according to claim 2, characterized in that, The plant is rice, wheat, or glass lettuce.

4. The application according to claim 2, characterized in that, The growth and development refers to increasing the root length and / or root weight, and the bud length and / or bud weight of seedlings after seed germination.

5. A biological agent for promoting plant growth, characterized in that, It includes the *Cercospora filamentosa* as described in claim 1.

6. The use of the *Ceratophyllum demersum* as described in claim 1 as a plant endophyte in the production of plant-absorbable nitrogen fertilizer, potassium fertilizer, and / or starch degradation.

7. The use of the *Cercospora filamentosa* as described in claim 1 in inhibiting the growth of *Colletotrichum discoidus* and / or *Fusarium graminearum*.

8. The application of the *Ceratophyllum demersum* as described in claim 1 in killing pepper aphids.

9. A biological control agent, characterized in that, The biological control agent contains the *Cercospora filamentosa* as described in claim 1, and can inhibit *Colletotrichum discus*, *Fusarium graminearum*, or *Aphidida citrinum*, or control plant diseases caused by *Colletotrichum discus*, *Fusarium graminearum*, or *Aphidida citrinum*.

10. A bio-organic fertilizer, characterized in that, It includes the *Silky Scale* fungus as described in claim 1; the bio-organic fertilizer acts as a plant endophyte to generate plant-absorbable nitrogen fertilizer, potassium fertilizer, and / or degraded starch.

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