Chaetomium globosum DP14 and application thereof

Abstract

The invention discloses a chaetomium globosum strain DP14 and an application of the chaetomium globosum strain DP14. The chaetomium globosum DP14 provided by the invention is preserved in the China Center for Type Culture Collection on June 10, 2025, and the preservation number of the chaetomium globosum DP14 is CCTCC (China Center for Type Culture Collection) NO: 20251324. The fermentation extract of the DP14 provided by the invention shows remarkable inhibitory activity on various plant pathogenic bacteria and fungi, and especially has a prominent inhibitory effect on pathogenic bacteria such as bacillus subtilis, magnaporthe grisea and cryptothecium elaticum. In addition, a fermentation product of the strain also has excellent oxidation resistance. The chaetomium globosum strain enriches chaetomium globosum resources, metabolites of the chaetomium globosum strain can be used for developing broad-spectrum and efficient biopesticides or antibacterial agents, and the chaetomium globosum strain is suitable for green prevention and control of plant diseases.

Description

Technical Field

[0001] This invention relates to the field of microbial control technology, specifically to a strain of Chaetomium DP14 and its applications. Background Technology

[0002] Microorganisms, as an important component of the ecosystem, play a crucial role in protecting plants from pathogens. The phyllosphere, encompassing leaves, stems, flowers, and fruits, is a vital ecological niche for plants, providing a vast habitat for many microorganisms. Some microorganisms exist epiphytically on the plant surface, while others colonize tissues as endophytes; these microbial communities associated with the phyllosphere habitat are called phyllosphere microbes. The phyllosphere environment is harsh and variable, allowing only highly adaptable microorganisms to colonize through selection. These microorganisms interact with plants over long periods, gradually establishing various ecological relationships such as mutualism, antagonism, and competition. Differences in plant species, geographical location, and growing season lead to variations in phyllosphere microbes across different hosts, resulting in diversity. This diversity makes the phyllosphere a rich repository of biocontrol microorganisms, representing a largely untapped functional microbial resource. Therefore, systematically isolating and screening phyllosphere microorganisms from different plants and discovering novel microbial resources with antagonistic functions against forest pathogens is of significant theoretical and practical importance for developing efficient and safe biocontrol agents. It also lays the theoretical foundation for the comprehensive development and sustainable utilization of biocontrol microbial resources. Summary of the Invention

[0003] The purpose of this invention is to provide a Chaetomium DP14 strain with multiple pathogen control capabilities, which has promising applications in the field of microbial biocontrol.

[0004] To achieve the above objectives, the present invention provides a strain of Chaetomium globosum ( Chaetomiumglobosum DP14 was deposited at the China Center for Type Culture Collection on June 10, 2025, with accession number CCTCC NO:20251324.

[0005] The *Chaetoceros DP14* provided by this invention can be used to prepare biological agents that inhibit plant pathogenic microorganisms, including bacteria and fungi.

[0006] Preferably, the bacteria mentioned above include *Ralstonia solanacearum* (Eucalyptus fusarium wilt). Ralstonia solanacearum Agrobacterium tumefaciens ( ), Agrobacterium tumefaciens ), Tomato scab pathogen ( Xanthomonas vesicatoria ), cucumber angular leaf spot fungus ( Pseudomonas lachrymans ), hemolytic staphylococci ( Staphylococcus haemolyticus ) or Bacillus subtilis ( Bacillus subtilis Any one or more of the following.

[0007] Preferably, the fungus mentioned above includes *Taro white mold* (*Taro white mold*). Agroathelia rolfsii ), *Euonymus stearens* ( Pesudocryphonectria elaeocarpicola Fusarium graminearum ( ), Fusarium gramineae ), Cinnamon twig blight fungus ( Lasiodiplodia pseudotheobromae ), African neem root rot fungus ( Pyrroderma harmful Rice blast fungus ( Magnaporthe rice ) or Camellia anthrax bacteria ( Colletotrichum gloeosporioides Any one or more of the following.

[0008] The present invention also provides a microbial fermentation extract, which is obtained by fermenting the above-mentioned Chaetomium DP14 in PDA, PDB or rice culture medium, followed by cold extraction with ethyl acetate and concentration. This fermentation extract can be used in the preparation of antibacterial or antioxidant agents.

[0009] The present invention also provides an antioxidant preparation prepared from the above-mentioned fermentation extract.

[0010] The present invention also provides a method for the prevention and control of plant diseases by applying Chaetomium DP14 or the above-mentioned fermented extract to plants or their growing environment; wherein the plant diseases are caused by plant pathogenic bacteria and / or fungi; The bacteria included are eucalyptus wilt pathogens (… Ralstonia solanacearum Agrobacterium tumefaciens ( ), Agrobacterium tumefaciens ), Tomato scab pathogen ( Xanthomonas vesicatoria ), cucumber angular leaf spot fungus ( Pseudomonas lachrymans ), hemolytic staphylococci ( Staphylococcus haemolyticus ) or Bacillus subtilis ( Bacillus subtilis ); The fungus includes *Sclerotium truncatum* (taro white rot fungus) Agroathelia rolfsii ), *Euonymus stearens* ( Pesudocryphonectria elaeocarpicola Fusarium graminearum ( ), Fusarium gramineae ), Cinnamon twig blight fungus ( Lasiodiplodia pseudotheobromae ), African neem root rot fungus ( Pyrroderma noxium Rice blast fungus ( Magnaporthe rice ) or Camellia anthrax bacteria ( Colletotrichum gloeosporioides ).

[0011] The present invention has the following advantages: This invention provides a Chaetomium DP14 strain, enriching the microbial resources of Chaetomium. Furthermore, verification has shown that the strain provided by this invention has inhibitory effects on a variety of pathogens, demonstrating significant application prospects in the field of microbial biocontrol. Attached Figure Description

[0012] Figure 1 The strain in this invention C.globosum Morphological results of DP14.

[0013] Figure 2 The results of the phylogenetic clustering tree constructed based on the rDNA-ITS sequence of strain DP14.

[0014] Figure 3 The results are obtained by high-performance liquid chromatography of DP14 extracts obtained from PDA, PDB, and rice fermentation.

[0015] Figure 4 The inhibitory effect of DP14 PDB fermentation extract at a concentration of 2 mg / mL on seven plant pathogenic fungi was measured.

[0016] Figure 5 The inhibitory effect of DP14 PDA fermentation extract at a concentration of 2 mg / mL on seven plant pathogenic fungi was measured.

[0017] Figure 6 The inhibitory effects of different concentrations of DP14 PDB fermentation extract on taro white rot fungus (BJ) were investigated.

[0018] Figure 7 The inhibitory effects of different concentrations of DP14 PDB fermentation extract on *Elaeocarpus oryzae* (DY) were investigated.

[0019] Figure 8 The inhibitory effects of different concentrations of DP14 PDB fermentation extract on Fusarium graminearum (Fg).

[0020] Figure 9 The inhibitory effects of different concentrations of DP14 PDB fermentation extract on Cinnamomum cassia twig blight (G1) were investigated.

[0021] Figure 10 The inhibitory effects of different concentrations of DP14 PDB fermentation extract on HGB (Hemiberlesia lataniae) were investigated.

[0022] Figure 11 The inhibitory effects of different concentrations of DP14 PDB fermentation extract on rice blast fungus (Mo).

[0023] Figure 12 To investigate the inhibitory effects of different concentrations of DP14 PDB fermentation extract on *YC* anthracnose pathogen of *Camellia oleifera*. Detailed Implementation

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Note: Unless otherwise specified, the experimental methods in the following examples are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0026] Partial culture medium: Potato Dextrose Agar (PDA) medium: 200 g potato, 20 g agar, 20 g glucose, bring to a final volume of 1000 mL with deionized water. Sterilize at 121 °C for 15-20 min. PDB medium is prepared by removing agar from PDA.

[0027] Rice culture medium: Add 15g of rice and 15mL of deionized water to a wide-mouth bottle, and sterilize by moist heat at 121℃ for 15~20min.

[0028] LB medium (Luria-Bertani medium): 5 g sodium chloride, 5 g yeast extract, 10 g peptone, 20 g agar, add deionized water to a final volume of 1000 mL. Sterilize by moist heat at 121 °C for 15-20 min. LB liquid medium does not contain agar.

[0029] Some of the tested bacteria: The tested bacteria included *Eucalyptus globulus* (… Ralstonia solanacearum G - Agrobacterium tumefaciens ( ), Agrobacterium tumefaciens G - ), Tomato scab pathogen ( Xanthomonas vesicatoria G - ), cucumber angular leaf spot fungus ( Pseudomonas lachrymans G - ), hemolytic staphylococci ( Staphylococcus haemolyticus G + ) and Bacillus subtilis ( Bacillus subtilis G + ).

[0030] The tested fungi included *Sclerotium truncatum* (taro white rot fungus). Agroathelia rolfsii BJ), *Euonymus stearens* (B ... Pesudocryphonectria elaeocarpicola DY), Fusarium graminearum ( Fusarium gramineae Fg), Cinnamon twig blight fungus ( Lasiodiplodia pseudotheobromae G1), African neem root rot fungus (G1), Pyrroderma harmful HGB), rice blast fungus ( Magnaporthe oxyzae Mo) and Camellia anthrax bacterium ( Colletotrichum gloeosporioides YC).

[0031] Example 1: Isolation and Identification of Strains 1. Isolation of strains Resource fungi were isolated from the leaves of different plants. The tested plants included Podocarpus brevifolia (…). Podocarpus large-leaved ), Camellia chrysantha ( Camellia impressinervis ), Golden Camellia sinensis ( Camellia euphlebia ), common camellia ( Camellia japonica ), thorny oak ( Quercus spinosa ) and peach ( Amygdalus persica The fungal isolation method involved placing the sample, after rinsing with running water, in a clean bench and disinfecting it with 75% alcohol for 30 seconds, followed by 0.2% mercuric chloride for 1 minute to complete surface disinfection. After air-drying and trimming, the sample was placed in a solution containing 500 μg / mL... -1 Streptomycin sulfate was cultured on PDA plates at 28 °C for 3–7 days. Only strains with inconsistent colony morphology were retained based on morphological observation. After three subcultures for activation, the cultures were stored at 4 °C.

[0032] It can be seen that a total of 45 antagonistic bacterial candidate strains were obtained, and the strain codes are DP01~45 respectively. Camellia anthracnose pathogens (…) were selected. C. gloeosporioides ) and *Elaeocarpus decipiens* ( P. elaeocarpicola As the pathogen, DP14 was further screened for antagonistic bacteria through plate confrontation. The results showed that DP14 had a significant inhibitory effect on *Camellia oleifera* anthracnose and *Elaeocarpus decipiens* blight, significantly inhibiting the growth and spread of pathogenic hyphae, forming obvious inhibition zones, and effectively limiting the extension of pathogenic colonies to the edge of the plate.

[0033] 2. Identification of strains Morphological identification was performed on DP14 bacteria that had been cultured for 3-30 days and were growing well. The morphology of the colonies and the growth status of the hyphae were observed. Fresh hyphae from the edge of the colonies were picked with a sterile needle to prepare temporary slides. The morphological characteristics of the hyphae and spores were carefully observed using an optical microscope (10×40). The width of the hyphae and the size of the spores were measured and photographed. The morphological characteristics of the hyphae and spores were described, and morphological identification was performed with reference to relevant literature.

[0034] The colony morphology of DP14 was obtained as follows: Figure 1As shown, 'a' represents the upper surface of the colony (3d), 'b' the lower surface (3d), 'c' the conidia, and 'd' the cleistothecia. The colony is white, flat, with neat edges and a clear boundary. The hyphae grow rapidly, extending radially outward from the center. In the later stages of growth, the hyphae turn dark green and begin to produce dark green spore masses. The upper surface of the colony is dark green, while the lower surface is yellowish-green. Under a microscope, the hyphae are septate, slightly curved or straight, and slightly rough. The spores are broadly oval with slightly pointed ends. The morphology of this strain is consistent with the description of *Chaetomium globosum*, and further molecular identification is needed.

[0035] DP14, a test bacterium that has grown well for 3-7 days, was selected for molecular identification. An appropriate amount of fresh mycelium was picked and placed into 50 μL of PrepMan. TM The fungal DNA template was obtained by centrifuging the Ultra sample Preparation Reagent in a 1.50 mL sterile centrifuge tube at 100°C for 10 min and then at 13000 rpm for 3 min.

[0036] DNA PCR amplification and detection: using universal primers ITS4 / ITS5 Amplification of the intracellular transcribed spacer region (ITS) gene fragment was performed. The PCR reaction mixture was set to 25 μL, containing 12 μL of 2×Taq PCR MasterMix, 11 μL of ddH2O, 0.5 μL each of forward and reverse primers, and 1 μL of DNA template. The mixed reaction solution was placed in a PCR instrument for amplification. PCR amplification conditions were: 95℃ pre-denaturation for 4 min; (95℃ denaturation for 30 s, 55℃ annealing for 30 s, 72℃ extension for 45 s) × 34 cycles; 72℃ extension for 10 min; and storage at 12℃ indefinitely. The PCR amplification products were bidirectionally sequenced by Shanghai Sangon Biotech.

[0037] After obtaining the ITS gene sequence, the complete sequence was assembled using DNAMAN software. The complete sequence was then used to perform a homology search in the GenBank database using the Blast program, downloading sequences with high similarity and sequences from closely related genera. Sequence processing was performed using MAFTT version 7, and a phylogenetic tree was constructed using MEGA 7.0.26 software. Neighbor-joining was used to establish the phylogenetic tree. After model fit analysis using MEGA 7.0 software, the optimal model for constructing the phylogenetic tree was determined to be the Kimura 2-parameter (Gamma). The support rate of each node in the phylogenetic tree was evaluated using a bootstrap method, repeated 1000 times in the test. The bootstrap values ​​are shown at each node.

[0038] After obtaining the ITS sequence of strain DP14, a BlAST homology search was performed on NCBI. Suitable closely related species were selected to construct a phylogenetic tree for cluster analysis. The phylogenetic tree was constructed using MEGA 7.0 software, and the results are as follows: Figure 2 As shown. According to the phylogenetic tree, the ITS sequence of DP14 is similar to... Chaetomiumglobosum (MH858130.1, OW987404.1) clustered on the same branch, with a genetic distance of 0 and a self-spreading support of 99%. Based on morphological identification results, DP14 was identified as belonging to the superfamily Sordariomycetidae, family Chaetomiaceae, and genus Chaetomi. Chaetomium The fungus, identified as DP14, was identified as *Chaetomium globosa*. Chaetomiumglobosum ).

[0039] The strain was deposited at the China Center for Type Culture Collection on June 10, 2025, with accession number CCTCC NO: 20251324.

[0040] Experiment Example 2 1. C. globosum Preparation and liquid chromatography analysis of DP14 extract C. globosum DP14 was subjected to large-scale fermentation using PDA (30 days, dark, 28°C, static), PDB (14 days, dark, 28°C, shake culture, 150 r / min), and rice culture medium (30 days, dark, 28°C, static), with yields of 10 L, 24 L, and 3.0 kg respectively. After fermentation, the PDA fermentation product was crushed and placed in a glass jar, and ethyl acetate was added for cold extraction. After 7 days, the mixture was filtered, and the filtrate was concentrated to dryness using a rotary evaporator to obtain the extract. This process was repeated 5 times to obtain the final extract. C. globosum DP14 PDA fermentation extract. After fermentation in PDB medium, the bacterial solution and mycelia were separated by filtration through gauze. The bacterial solution was extracted with ethyl acetate, and the extract was concentrated to dryness using a rotary evaporator to obtain the bacterial solution extract. The mycelia were repeatedly freeze-thawed three times and then extracted with ethyl acetate for 3 days. The extract was concentrated to obtain the mycelial extract. This process was repeated three times. Finally, the bacterial solution extract and mycelial extract were combined to obtain the final product. C. globosum DP14 PDB fermentation extract. After rice culture medium fermentation, the fermentation product was placed in a glass jar, ethyl acetate was added, and cold extraction was performed for 7 days. The mixture was then filtered, and the filtrate was concentrated to dryness using a rotary evaporator to obtain the extract. This process was repeated 5 times to obtain the final extract. C. globosum DP14 Rice Fermentation Extract.

[0041] Take a small amount of the extract into a clean vial, dry it with nitrogen evaporation, weigh it, and dissolve it in chromatographic methanol to control the concentration at 10 mg / mL. Filter the solution through a 0.22 μm filter membrane to remove impurities to ensure the best results for analysis on a high-performance liquid chromatograph (HPLC). The experiment used methanol-water reversed-phase gradient elution. C. globosum The elution gradients for each DP14 extract are as follows: isocratic elution with 30% chromatographic methanol for 0-1 min; linear elution with 100% chromatographic methanol for 1-16 min; linear elution with 100% chromatographic methanol for 16-21 min; linear elution with 100% chromatographic methanol for 21-22 min; and column equilibration with 30% chromatographic methanol for 22-29 min (0.1 mL of trifluoroacetic acid was added to each liter of mobile phase).

[0042] After fermentation, extraction, and concentration, the final product is obtained. C. globosum DP14 PDA fermentation extract 14.86g, PDB fermentation extract 45g, rice fermentation extract 57.1g. The high-performance liquid chromatograms of each extract are shown below. Figure 3 As shown in the figure, a is PDA fermentation extract, b is PDB fermentation extract, and c is rice fermentation extract. It can be seen from the figure that... C. globosum The main components of the secondary metabolites produced by DP14 under different culture conditions varied considerably. The PDA fermentation product and the rice fermentation product had similar compositions, both being low to medium polar compounds. The main compounds eluted after 15 min. At the same concentration, the absorption peak of the main compounds in the PDA fermentation extract was higher than that in the rice fermentation extract, indicating that the relative content of the main compounds in the PDA fermentation extract was higher. The compounds in the PDB fermentation extract eluted between 5 and 18 min, indicating that the PDB fermentation extract mainly consisted of high to medium polar compounds.

[0043] 2. Determination of antibacterial activity of extracts The determination was performed using a multi-well plate-MTT bioautoradiography method. C.globosum Inhibitory activity of DP14 fermentation extract against various tested pathogenic bacteria. Before activity assay, the tested pathogenic strains were activated by LB agar culture (28℃, dark) for 48 h. Then, single colonies were picked and incubated in LB liquid medium with shaking (28℃, dark, 150 rpm) for 24 h. The bacterial concentration was then diluted to 10. 8 cfu·mL -1 For later use. Accurately weigh 20.00 mg. C. globosumThe DP14 PDA fermentation extract was dissolved in 1 mL of 30% acetone solution and then diluted to eight concentrations using the 2:1 dilution method: 20.00, 10.00, 5.00, 2.50, 1.25, 0.625, 0.3125 and 0.15625 mg / mL. The positive control was streptomycin sulfate, and the negative control was 30% acetone. In a 96-well plate, 90 μL of bacterial culture and 10 μL of a series of test sample solutions were added to each well to achieve final concentrations of 2.00, 1.00, 0.50, 0.25, 0.125, 0.0625, 0.03125, and 0.015625 mg / mL, respectively. Each test sample solution was in triplicate. After incubation on a shaker (28℃, 150 r / min) for 24 h, the plate was removed, and 10 μL of 5 mg / mL MTT chromogenic reagent was added to each well. The plate was then incubated on a shaker for another 4 h (28℃, 150 r / min). After centrifugation, the supernatant was removed, and 150 μL of pure DMSO solution was added to each well. After thorough dissolution, 100 μL of the reaction solution was transferred from each well to a new 96-well plate, and the absorbance (OD) was measured at 510 nm.

[0044]

[0045] The inhibition rates at different concentrations were calculated. Five concentrations were selected, and the logarithm of different extract concentrations was plotted on the x-axis, with the biostatistical probability of the inhibition rate on the y-axis. Data processing was performed in Excel and GraphPad Prism software to obtain the virulence regression equation and regression coefficients. The half-maximal effect concentration (IC50) was also calculated. 50 The relative inhibitory effects of different extracts were compared using the ) value.

[0046] get C. globosum The inhibitory activities of various fermentation extracts of DP14 against the tested pathogenic bacteria are shown in Table 1. As can be seen from the table... [[ID=2,6]]C. globosum The DP14 PDA fermentation extract showed strong inhibitory activity against all tested strains, and its inhibitory activity was stronger than that of the PDB fermentation extract. C. globosum Different fermentation extracts of DP14 showed the greatest difference in inhibitory activity against *Ralstonia solanacearum*, the causal agent of bacterial wilt of eucalyptus. The IC50 of PDA fermentation products against *Ralstonia solanacearum* was [not specified]. 50 The value was 36.59 ± 2.32 μg / mL, while the IC50 of the PDB fermentation extract was... 50 The value was 1495.17 ± 112.48 μg / mL. Among the tested pathogenic bacteria, the PDA fermentation extract showed the best inhibitory activity against Bacillus subtilis, with an IC50 value of 1495.17 ± 112.48 μg / mL. 50The value was 28.45 ± 0.77 μg / mL, followed by hemolytic Staphylococcus (IC50). 50 =32.56 ± 1.41 μg / mL), in addition, the IC50 against eucalyptus bacterial wilt and cucumber angular leaf spot fungus was 32.56 ± 1.41 μg / mL. 50 The concentration was also below 50 μg / mL; except for the inhibitory activity of PDA fermentation products against hemolytic Staphylococcus aureus which was higher than that against the positive control, the inhibitory activity against other pathogens was lower than that against the positive control. C. globosum Although the inhibitory activity of DP14 PDB fermentation extract against pathogenic bacteria was weaker than that of PDA fermentation extract, it still showed excellent antibacterial activity, with the best inhibitory activity against Bacillus subtilis, IC50. 50 The value was 91.19 ± 2.43 μg / mL, followed by hemolytic Staphylococcus (IC50). 50 = 146.07 ± 11.09 μg / mL), exhibiting the weakest inhibitory activity against *Fusarium wilt*, the causal agent of eucalyptus wilt, with an IC50 value of 146.07 ± 11.09 μg / mL. 50 The value was 1495.17 ± 112.48 μg / mL.

[0047] Table 1 C. globosum Antimicrobial data of various fermentation extracts of DP14 against tested pathogenic bacteria.

[0048] 3. Determination of antifungal activity of extracts C. globosum The antifungal activity of the DP14 fermentation extract was determined using the mycelial growth rate method. 630 mg of the extract was weighed... C. globosum Each DP14 fermentation extract was dissolved in 2.1 mL of dimethyl sulfoxide (DMSO), and then 4.9 mL of sterile water was added. The solutions were then diluted sequentially with 30% DMSO using a 2:5 dilution method to obtain eight different concentrations. One mL of each concentration of extract solution was added to 44 mL of sterile PDA (cooled to 60°C), thoroughly mixed, and then poured into three sterile petri dishes, approximately 15 mL per dish, resulting in drug-containing culture media with final sample concentrations of 2.00, 1.00, 0.50, 0.25, 0.125, 0.0625, 0.03125, and 0.015625 mg / mL. Using a punch, well-grown pathogens were atomized into 7 mm diameter mycelial discs along the edge, and inoculated onto drug-containing PDA plates with the discs facing down. PDA plates containing 30% DMSO served as a negative control, and PDA plates containing 98.4% carbendazim served as a positive control. Each treatment was repeated three times. The inoculated culture media were incubated at 28°C until the colonies in the negative control group reached 2 / 3 of the petri dish area. The colony diameter under different treatments was measured using the cross-hatching method, and the inhibition rate was calculated.

[0049] The formula for calculating the antibacterial rate is as follows:

[0050] The inhibition rates at different concentrations were calculated. Five concentrations were selected, and the logarithm of different extract concentrations was plotted on the x-axis, with the biostatistical probability of the inhibition rate on the y-axis. Data processing was performed in Excel and GraphPad Prism software to obtain the virulence regression equation and regression coefficients. The half-maximal effect concentration (EC50) was also calculated. 50 The relative inhibitory effects of different extracts were compared using the ) value.

[0051] First, the concentration at 2.00 mg / mL was measured. C. globosum The antifungal activities of DP14 PDA fermentation extract and PDB fermentation extract against the tested pathogenic fungi are shown in Table 2. As can be seen from the table, C. globosum The PDA and PDB fermentation extracts of DP14 showed certain inhibitory activity against seven plant pathogens. C. globosum The PDB fermentation extract of DP14 showed the highest inhibition rate of 78.52% against rice blast fungus (Mo), and the inhibition rates against *Elaeocarpus decipiens* (DY), *Fusarium graminearum* (Fg), and *Alternaria oleifera* anthracnose fungus (YC) were all greater than 50%. The PDA fermentation extract showed significantly stronger inhibitory activity than the PDB fermentation extract. Except for the inhibition rate of 88.69% against *Fusarium graminearum* (Fg), the inhibition rates against the other six tested pathogenic fungi were all higher than 90%, and the inhibition rate against rice blast fungus (Mo) reached 100%. The inhibition activities against *G1* cinnamon twig blight fungus and *HGB* neem rot fungus both exceeded 95%.

[0052] Table 2. At a concentration of 2 mg / mL C. globosum Inhibition rate of DP14 extract against 7 pathogenic fungi

[0053] The inhibitory effect of DP14 PDB fermentation extract at a concentration of 2 mg / mL on seven plant pathogenic fungi is shown in the figure. Figure 4 As shown, the inhibitory effect of DP14 PDA fermentation extract at a concentration of 2.00 mg / mL on seven plant pathogenic fungi is shown in the figure. Figure 5 As shown; where, Figure 4 , Figure 5In the diagram, 'a' represents *B. taro* scab (BJ), 'b' represents *D. t ...

[0054] Further investigation was conducted into the inhibitory effects of different concentrations of DP14 PDA fermentation extract on seven pathogens (namely, *B. taro white mold*, *D. t. t. t.*, *F. graminearum*, *G. t. cinnamon twig blight*, *H. t. t.*, *M. graminearum*, and *Y. t. t. t. t.*). Plate growth results are shown below. Figures 6 - 12 In each figure, the left side represents the experimental group, and the right side represents the positive control group; the central plate in each figure represents the negative control group; numbers 1-6 in the figures represent concentrations decreasing in order of magnitude. In the experimental group, the concentrations of 1-6 are 1.00, 0.50, 0.25, 0.125, 0.0625, and 0.03125 mg / mL, respectively, while in the positive control group, the concentrations of 1-6 are 5.00, 2.50, 1.25, 0.625, 0.3125, and 0.15625 μg / mL, respectively. Figure 6 It can be seen that, C. globosum The inhibitory effect of DP14 PDA fermentation extract on *Sclerotium truncatum* (BJ) showed a significant concentration-dependent relationship; the inhibitory effect weakened with decreasing extract concentration. In contrast, the positive control, carbendazim, did not show significant inhibitory activity against *Sclerotium truncatum* (BJ) at the experimental concentration. Figure 7 It can be seen that, C. globosum The inhibitory effect of DP14 PDA fermentation extract on *Elaeocarpus decipiens* (DY) was concentration-dependent; the inhibitory effect weakened with decreasing extract concentration, but strong inhibitory activity was still observed at concentration 5 (0.0625 mg / mL). In contrast, the positive control group showed a significant difference in inhibitory effect between concentrations 5 and 6. At concentrations of 1-5, carbendazim completely inhibited the growth of *Elaeocarpus decipiens* (DY). Figure 8 It can be seen that, C.globosumThe inhibitory effects of DP14 PDA fermentation extract and the positive control carbendazim on Fusarium graminearum (Fg) were both concentration-dependent. C.globosum DP14 PDA fermentation extract at concentrations above 0.125 mg / mL significantly inhibited the growth of Fusarium graminearum (Fg); according to Figure 9 It can be seen that, C.globosum The inhibitory effects of DP14 PDA fermentation extract and the positive control carbendazim on *Cinnamomum cassia* twig blight (G1) were concentration-dependent. C.globosum The inhibitory effect of DP14 PDA fermentation extract on *Cinnamomum cassia* twig blight (G1) was significantly weakened at concentrations below 0.25 mg / mL, while the positive control carbendazim still showed a strong inhibitory effect at a concentration of 0.15625 μg / mL; according to Figure 10 It can be seen that, C.globosum The relationship between the concentration of DP14 PDA fermentation extract and its inhibitory effect on HGB (neem root rot fungus) is complex. When the sample concentration is below 1.00 mg / mL, there are significant differences in the data between each flat treatment at each experimental concentration, requiring further investigation. C.globosum The relationship between the concentration of DP14 PDA fermentation extract and its inhibitory effect on *H. neem* (African neem brown root causal agent) was investigated, while at the experimental concentration, the positive control carbendazim did not show inhibitory activity against *H. neem* (African neem brown root causal agent). According to... Figure 11 It can be seen that, C.globosum The inhibitory effects of DP14 PDA fermentation extract and the positive control carbendazim on rice blast fungus (Mo) were both concentration-dependent. C.globosum The DP14 PDA fermentation extract significantly inhibited the growth of rice blast fungus (Mo) at concentrations above 0.125 mg / mL, while the positive control carbendazim showed poor inhibitory activity against Mo at concentrations below 1.25 μg / mL. Figure 12 It can be seen that, C.globosum The inhibitory effects of DP14 PDA fermentation extract and the positive control carbendazim on *Camellia oleifera* anthracnose fungus (YC) showed a concentration-dependent relationship. C.globosum The inhibitory effect of DP14 PDA fermentation extract on Camellia anthracnose (YC) was significantly weakened when the concentration was below 0.25 mg / mL, while the positive control carbendazim still had a strong inhibitory effect at a concentration of 0.3125 μg / mL.

[0055] Further measurements were performed. C. globosum EC50 of DP14 PDA fermentation extract against 7 plant pathogenic fungi 50 The values ​​are shown in Table 3 below. From the table, we can see... C. globosumEC50 of DP14 PDA fermentation extract against 7 plant pathogenic fungi 50 The values ​​were all below 500 mg / mL, with the best inhibitory activity against *Elaeocarpus decipiens* pseudocryptocrystiae*, EC 100%. 50 The value was 37.54 ± 2.32 μg / mL, followed by rice blast fungus, EC 100. 50 The value was 117.98 ± 2.01 μg / mL, and EC... 50 Fusarium graminearum (EC) also has concentrations below 200 μg / mL. 50 = 163.84 ± 4.59 μg / mL), with relatively poor inhibitory activity against *Sclerotium truncatum* causal agent, EC 163.84 ± 4.59 μg / mL. 50 The value was 416.83 ± 16.63 μg / mL, which is effective against Camellia oleifera anthracnose (EC). 50 = 224.87 ± 8.21 μg / mL), Cinnamomum cassia twig blight fungus (EC) 50 = 234.62 ± 8.79 μg / mL) and African neem root rot fungus (EC) 50 EC (242.88 μg / mL) 50 The values ​​were all between 200-300 μg / mL. Based on the above results, C. globosum The DP14 PDA fermentation extract showed significant inhibitory effects against seven plant pathogenic fungi, indicating that it has a broad-spectrum antibacterial effect, but there is still a large gap compared with the positive control carbendazim.

[0056] Table 3 C. globosum EC50 of DP14PDA fermentation extract against 7 plant pathogenic fungi 50 value

[0057] Note: - indicates no data. 4. Determination of DPPH free radical scavenging rate of extract Determination using the multi-well plate-DPPH method C. globosum The scavenging ability of various fermentation extracts of DP14 against DPPH free radicals was investigated. The specific experimental procedures are as follows: Accurately weigh 20.00 mg of DPPH, dissolve it in 100 mL of anhydrous ethanol, and shake thoroughly to prepare a DPPH solution with a final concentration of 0.20 mg / mL. Sample solution preparation: Accurately weigh 2.00 mg... C. globosumEach fermentation extract of DP14 was dissolved in 1 mL of DMSO to prepare a 2.00 mg / mL stock solution. The stock solution was then diluted 2 / 3 times with DMSO to obtain eight sample solutions of varying concentrations, including the stock solution. Reaction system setup: In a 96-well plate, 80 μL of 0.2 mg / mL anhydrous DPPH ethanol solution and 20 μL of a series of sample solutions were added sequentially, resulting in sample concentrations of 200.00, 100.00, 50.00, 25.00, 12.50, 6.25, 3.125, and 1.5625 μg / mL. 2,6-Di-tert-butyl-p-cresol (BHT) was used as a positive control, and 20 μL of DMSO was used as a negative control. The mixture was shaken well under light and reacted in a 37°C water bath for 30 min. Absorbance assay: The absorbance of each well was measured at 517 nm using a microplate reader. Each sample was tested in triplicate, and each replicate was measured three times. The scavenging rate of the test sample against DPPH free radicals was calculated using the following formula:

[0058]

[0059] The free radical scavenging rates at different concentrations were calculated. Five concentrations were selected, and the logarithm of the concentration of different extracts was plotted on the x-axis, with the biostatistical probability of the scavenging rate on the y-axis. Data processing was performed in Excel and GraphPad Prism software to obtain the linear regression equation and regression coefficients. The half-maximal effect concentration (IC50) was also calculated. 50 The relative scavenging effects of different extracts were compared using the scavenging value.

[0060] DPPH free radical scavenging rate determination ​ The antioxidant data of various fermentation extracts from DP14 are shown in Table 4 below. The data in the table show... ​ All fermentation extracts of DP14 exhibited excellent antioxidant capacity, with the capacity increasing from low to high as follows: rice fermentation extract, PDA fermentation extract, and PDB fermentation extract. Furthermore, the IC50 of the PDB fermentation extract was significantly higher. 50 The concentration was 6.74 ± 0.06 μg / mL, significantly lower than the positive control BHT (14.40 ± 0.31 μg / mL), indicating that... ​ DP14 PDB fermentation extract has great potential for development in the field of antioxidants.

[0061] Table 4 Antioxidant data of various fermentation extracts from DP14

[0062] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A strain of Chaetomium coccidioides ( Chaetomium globosum DP14, characterized in that, This DP14 was deposited at the China Center for Type Culture Collection on June 10, 2025, with accession number CCTCC NO: 20251324.

2. The use of Chaetomium DP14 as described in claim 1 in the preparation of biological agents for inhibiting plant pathogenic microorganisms.

3. The application as described in claim 2, characterized in that, The plant pathogenic microorganisms include bacteria and fungi.

4. The application according to claim 3, characterized in that, The bacteria include *Liquidambar eucalyptus* (Eucalyptus blight pathogen). Ralstonia solanacearum Agrobacterium tumefaciens ( ), Agrobacterium tumefaciens ), Tomato scab pathogen ( Xanthomonas vesicatoria ), cucumber angular leaf spot fungus ( Pseudomonas lachrymans ), hemolytic staphylococci ( Staphylococcus haemolyticus ) or Bacillus subtilis ( Bacillus subtilis Any one or more of the following.

5. The application according to claim 3, characterized in that, The fungus includes *Taro white mold* (… Agroathelia rolfsii ), *Euonymus stearens* ( Pesudocryphonectria elaeocarpicola Fusarium graminearum ( ), Fusarium graminearum ), Cinnamon twig blight fungus ( Lasiodiplodia pseudotheobromae ), African neem root rot fungus ( Pyrrhoderma noxium Rice blast fungus ( Magnaporthe oryzae ) or Camellia anthrax bacteria ( Colletotrichum gloeosporioides Any one or more of the following.

6. A microbial fermentation extract, characterized in that, It is obtained by fermenting the Chaetomium DP14 of claim 1 in PDA, PDB or rice culture medium, followed by cold extraction with ethyl acetate and concentration.

7. The use of the fermentation extract as described in claim 6 in the preparation of antibacterial or antioxidant agents, characterized in that, The antibacterial properties described include those against bacteria or fungi. The bacteria included are eucalyptus wilt pathogens (… Ralstonia solanacearum Agrobacterium tumefaciens ( ), Agrobacterium tumefaciens ), Tomato scab pathogen ( Xanthomonas vesicatoria ), cucumber angular leaf spot fungus ( Pseudomonas lachrymans ), hemolytic staphylococci ( Staphylococcus haemolyticus ) or Bacillus subtilis ( Bacillus subtilis Any one or more of the following; The fungus includes *Sclerotium truncatum* (taro white rot fungus) Agroathelia rolfsii ), *Euonymus stearens* ( Pesudocryphonectria elaeocarpicola Fusarium graminearum ( ), Fusarium graminearum ), Cinnamon twig blight fungus ( Lasiodiplodia pseudotheobromae ), African neem root rot fungus ( Pyrrhoderma noxium Rice blast fungus ( Magnaporthe oryzae ) or Camellia anthrax bacteria ( Colletotrichum gloeosporioides Any one or more of the following.

8. An antioxidant preparation made from the fermentation extract of claim 6.

9. A method for controlling plant diseases, characterized in that, By applying the Chaetomium DP14 of claim 1 or the fermentation extract of claim 6 to the plant or its growing environment.

10. The prevention and control method according to claim 9, characterized in that, The plant diseases are caused by plant pathogenic bacteria and / or fungi; The bacteria included are eucalyptus wilt pathogens (… Ralstonia solanacearum Agrobacterium tumefaciens ( ), Agrobacterium tumefaciens ), Tomato scab pathogen ( Xanthomonas vesicatoria ), cucumber angular leaf spot fungus ( Pseudomonas lachrymans ), hemolytic staphylococci ( Staphylococcus haemolyticus ) or Bacillus subtilis ( Bacillus subtilis Any one or more of the following; The fungus includes *Sclerotium truncatum* (taro white rot fungus) Agroathelia rolfsii ), *Euonymus stearens* ( Pesudocryphonectria elaeocarpicola Fusarium graminearum ( ), Fusarium gramineae ), Cinnamon twig blight fungus ( Lasiodiplodia pseudotheobromae ), African neem root rot fungus ( Pyrroderma noxium ), rice blast fungus ( Magnaporthe rice ) or Camellia anthrax bacteria ( Colletotrichum gloeosporioides Any one or more of the following.

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