Fungal strain 41233 from xisha and its application

Abstract

The application discloses a fungus strain 41233 from Xisha and an application thereof, the taxonomic name of the fungus strain 41233 is Plectosphaerellaceae sp., the preservation number is GDMCC No. 67505, and the preservation date is December 19, 2025; the application of the fungus strain 41233 and a crude extract thereof in the preparation of a pathogenic bacteria inhibiting product is also disclosed; the fungus strain 41233 from Xisha has inhibiting activity on mango anthracnose fungus and / or pepper phytophthora; the crude extract of the fungus strain 41233 from Xisha has inhibiting activity on various anthracnose fungi, phytophthora, fruit rot fungi and the like, can be used for preparing a biocontrol agent or further mining active natural products, and provides a new green control method for plant disease prevention and control.

Description

Technical Field

[0001] This invention belongs to the field of microbial technology, specifically relating to a fungal strain 41233 from Xisha and its application. Background Technology

[0002] Islands are an important component of marine ecosystems, possessing relatively simple biodiversity compositions, thus serving as excellent natural laboratories for studying biological evolution. Recent research on island biodiversity has largely focused on plants, with less attention paid to microorganisms, particularly fungal communities within these ecosystems. These communities may exhibit entirely different evolutionary pathways, thus providing abundant resources for the discovery of novel fungi. Fungi are a significant source of natural bioactive substances, and their secondary metabolites provide a wealth of lead compounds for drug development. Unique and novel fungi participating in the co-evolution of island communities may possess distinctive metabolic strategies and pathways, thereby synthesizing secondary metabolites with novel skeletons. With the development of high-throughput sequencing technology, many unknown taxa remain undiscovered, highlighting the significant importance of in-depth exploration and utilization of such resources.

[0003] The Xisha Islands are an important tropical multi-ecosystem in China, integrating diverse ecological components such as islands, coral reefs, mangroves, and seagrass beds, and containing rich and diverse biological resources. A considerable amount of research has been conducted on endophytic microorganisms related to corals and mangroves, and the reported novel skeletons and substances with antibacterial and antitumor activities further illustrate their application potential. However, research on the coastal areas of the islands is relatively limited. Most coastal areas of the Xisha Islands are still in their nascent stages, with soil substrates mainly consisting of sandy soil mixed with coral particles, supporting only simple salt- and drought-tolerant pioneer plants. Similarly, the root microbial communities, under the stress of high temperature, high salinity, and strong sunlight, have evolved unique metabolic mechanisms to better occupy their required ecological niches. In this process, they are likely to produce a series of novel bioactive substances, representing a high-quality microbial resource with significant research potential.

[0004] Hainan is an important production base for natural rubber, tropical fruits, winter melons and vegetables, and a seed breeding base for crops in southern my country. However, the island's hot and humid ecological environment makes tropical cash crops and vegetables highly susceptible to various agricultural pathogens throughout the entire process from planting to harvesting and transportation, severely impacting crop yield and quality. For example, anthracnose (Anthracnose genus) Colletotrichum ), Sickle genus ( Fusarium Phytophthora ( ) PhytophthoraPathogens such as [list of pathogens] have caused significant losses to various economic crops, including melons, vegetables, and fruits, severely hindering the development of related economic industries. Although chemical pesticides remain the most effective means of disease control, the long-term use of mainstream pesticides, coupled with the growth of pathogen resistance, has led to increasingly higher dosages and frequencies. This not only increases costs but also fails to effectively curb disease development, and is inconsistent with Hainan's green and sustainable development philosophy. Therefore, finding new, safe, effective, and environmentally compatible bio-based natural pesticides with fewer side effects is the mainstream approach to solving the current predicament. Summary of the Invention

[0005] The purpose of this invention is to provide a fungal strain 41233 from Xisha, which has inhibitory activity against a variety of agricultural pathogens.

[0006] Another objective of this invention is to provide the application of the aforementioned fungal strain 41233 in the preparation of pathogen-inhibiting products.

[0007] The final objective of this invention is to provide a crude extract of fungal strain 41233 from Xisha and its application in the preparation of pathogen-inhibiting products.

[0008] The first objective of this invention can be achieved through the following technical solution: a fungal strain 41233 derived from Xisha, wherein the taxonomic name of the fungal strain 41233 is... Plectosphaerellaceae sp. The accession number is GDMCC No. 67505, the accession date is December 19, 2025, the depositary institution is Guangdong Provincial Center for Microbial Culture Collection, the depositary address is 5th Floor, Building 59, No. 100 Xianlie Middle Road, Yuexiu District, Guangzhou, Guangdong Province, Institute of Microbiology, Guangdong Academy of Sciences.

[0009] The second objective of the present invention can be achieved by the following technical solution: the application of the above-mentioned fungal strain 41233 in the preparation of pathogen inhibitory products.

[0010] Preferably, the pathogen is *Hymenocortis moniliforme*, the pathogen causing mango anthracnose. Colletotrichum gloeosporioides and / or Phytophthora capsici Phytophthora capsici .

[0011] The last objective of the present invention can be achieved by the following technical solution: a crude extract of fungal strain 41233 from Xisha, obtained by fermentation and extraction of the fungal strain 41233.

[0012] In some embodiments of the present invention, the crude extract of the fungal strain 41233 is obtained by a method comprising the following steps:

[0013] (1) Seed culture: The fungal strain 41233 was inoculated onto a plate containing PDA (Potato Dextrose Agar) medium and cultured in the dark. The fungal block was then transferred to the seed culture medium and cultured in the dark again to obtain the seed culture.

[0014] (2) Solid fermentation: The seed liquid obtained in step (1) is inoculated onto rice ME solid culture medium and cultured in the dark to obtain fermentation product;

[0015] (3) Extraction of antibacterial active ingredients: The fermentation product obtained in step (2) was extracted with ethyl acetate under ultrasonic assistance. The extract was collected, filtered, and concentrated to remove all solvents, thus obtaining the crude extract of fungal strain 41233 from Xisha.

[0016] Preferably, the preparation method of the plate containing PDA culture medium in step (1) is as follows: 200g of peeled potatoes are added to 1000mL of purified water and boiled for 20-30min. The filtrate is obtained by filtering with gauze, adding 20g of glucose and 15-20g of agar and dissolving them completely. The volume is then adjusted to 1000mL with purified water and sterilized at 121℃ for 20min.

[0017] Preferably, in step (1), the fungal strain 41233 is inoculated onto a plate containing PDA medium and cultured at 28-32°C in the dark for 7 days.

[0018] Preferably, the seed culture medium in step (1) is prepared as follows: 4g of glucose, 4g of yeast extract, 10g of malt extract, and purified water are added to a final volume of 1000mL and sterilized at 121℃ for 20min.

[0019] Preferably, in step (1), the seed culture is obtained by culturing in the dark for 7 days at 28-32℃ and 180-200 rpm.

[0020] Preferably, the inoculation amount of the seed liquid in step (2) is 4-6% of the total mass of the rice ME solid culture medium.

[0021] Preferably, the rice ME solid culture medium in step (2) includes rice and ME liquid culture medium, and the ratio of the amount of rice to ME liquid culture medium is 10g: 10-12mL. The ME liquid culture medium is prepared as follows: 20g yeast extract, 1g peptone, 15g sucrose, purified water to a final volume of 1000mL, and sterilized at 121℃ for 20min.

[0022] Preferably, in step (2), the fermentation product is obtained after being cultured at 28-32℃ in the dark for 30 days.

[0023] Preferably, the fermentation product in step (3) is equal in volume to the ethyl acetate.

[0024] The present invention also provides the application of the crude extract of fungal strain 41233 from Xisha in the preparation of pathogen inhibitor products.

[0025] Preferably, the pathogen is *Phytophthora camphorata*. Phytophthora cinnamomi Phytophthora indicum Phytophthora nicotianae Phytophthora durianis YCG1 Phytophthora palmivora Banana anthracnose bacteria Colletotrichum musae Mango anthracnose fungus Colletotrichum gloeosporioides GX1655, the pathogen of rubber anthrax Colletotrichum australisinense Rubber anthrax bacterium HBCg01 Colletotrichum gloeosporioides Coconut fruit rot pathogens Thielaviopsis paradoxa Passion fruit rot fungus Diaporthe passifloricola One or more of them.

[0026] The present invention has the following advantages: the fungal strain 41233 from Xisha in the present invention has inhibitory activity against mango anthracnose fungus and / or pepper phytophthora. The crude extract of fungal strain 41233 from Xisha in the present invention has inhibitory activity against various anthracnose fungi, phytophthora fungi, fruit rot fungi and other pathogens. It can be used to prepare biocontrol agents or further explore active natural products, providing new green control methods for plant disease prevention and control. Attached Figure Description

[0027] Figure 1 This is a morphological diagram of strain 41233 in Example 1 of the present invention growing on a plate containing PDA medium;

[0028] Figure 2 The image shows the microscopic morphology of strain 41233 in Example 1 of this invention under an optical microscope, where AD represents the sporulation structure and conidia, E represents the hyphal ring and sporulation structure, AE has a scale bar of 10 μm, and F represents conidia with a scale bar of 5 μm.

[0029] Figure 3 The phylogenetic tree of strain 41233 in Example 1 of this invention is constructed based on the maximum likelihood method of ITS (only Bootstrap ≥ 70 values ​​are shown).

[0030] Figure 4 The results of the initial screening plate confrontation of strain 41233 in Example 2 of the present invention are shown, where A is the confrontation of Phytophthora capsici and B is the confrontation of Anthracnose mangoesii.

[0031] Figure 5This is the HPLC fingerprint of the crude extract of strain 41233 from Example 3 of the present invention, with the vertical axis representing nm and the horizontal axis representing min;

[0032] Figure 6 The antibacterial results of the crude extract of strain 41233 fermented in Example 3 of this invention are shown below. Pc It is *Phytophthora camphorata*. Tp It is a pathogen that causes coconut rot. Pn It is Phytophthora indicum. Cm It is caused by the fungus that causes banana anthracnose. Cg It is caused by mango anthracnose fungus. Pp It is *Phytophthora indica*, Dp It is a fungus that causes fruit rot in passion fruit. Pp 1 is Phytophthora palmis BS-6, Ca It is the rubber anthrax bacterium GX1655. P.ca It is *Phytophthora capsici*. Cg 1 represents the rubber anthrax bacterium HBCg01. Detailed Implementation

[0033] To further illustrate the technical means and effects of this invention, the following description, in conjunction with embodiments and accompanying drawings, further explains the invention. It is understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it.

[0034] Where specific techniques or conditions are not specified in the examples, they shall be performed in accordance with the techniques or conditions described in the literature in this field, or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased from legitimate channels.

[0035] Example 1

[0036] 1. Sample collection

[0037] The samples were collected from the rhizosphere soil of wild pineapple on the Xisha Island of the Xisha Islands in Sansha City, Hainan Province. After collection, the samples were placed in 50mL centrifuge tubes and stored at -20℃. They were then immediately prepared for separation upon returning to the laboratory.

[0038] 2. Sample separation

[0039] Take 1g of the collected sample and place it in a 10mL sterile centrifuge tube. Add 9mL of sterile water, shake, and sonicate to suspend the sample. Then dilute to 10 ... -2 10 -3 and 10 -4Take 50 μL of the sample supernatant and spread it onto PDA medium plates containing antibiotics. Set up 3 replicates for each dilution gradient. Incubate at 28-32℃ in the dark for 48 hours and then observe the purification plates. Pick the rapidly growing strains onto PDA medium plates and then cut them off. Pick single colonies of the slow-growing strains for culture. The above isolated and purified strains are cultured on plates for 14 days to obtain 41233 isolated and purified single colonies.

[0040] The preparation method of PDA culture medium plates containing antibiotics is as follows: 200g of peeled potatoes are added to 1000mL of purified water and boiled for 20-30 minutes. The mixture is then filtered through gauze to obtain the filtrate. 20g of glucose and 15-20g of agar are added and dissolved thoroughly. The volume is then adjusted to 1000mL with purified water. The resulting 1L PDA culture medium is sterilized at 121℃ for 20 minutes. After cooling to 60℃, 1mL of ampicillin (filtered and sterilized) with a concentration of 100mg / mL is added for later use.

[0041] 3. Strain identification

[0042] 3.1 Morphological identification

[0043] The isolated and purified 41233 single colonies were inoculated onto plates containing PDA medium using the spot inoculation method. They were cultured at 28-32℃ in the dark for 7-30 days to observe their colony morphology and microstructure. The above culture plates were taken, and sterile coverslips were inserted at an angle along the edge. After the colonies grew onto the coverslips, they were removed for observation.

[0044] The preparation method of plates containing PDA medium is as follows: 200g of peeled potatoes are added to 1000mL of purified water and boiled for 25min. The filtrate is obtained by filtering with gauze. 20g of glucose and 20g of agar are added and dissolved completely. The volume is then adjusted to 1000mL with purified water and sterilized at 121℃ for 20min.

[0045] The morphological identification results of strain 41233 are as follows:

[0046] The morphological reference of strain 41233 is the most similar taxonomic unit. Phaeochloridium The description method, Anamorphic chaetosphaeriaceous fungi from China, Wu, WP, Diao YZ FungalDiversity, 2022, 116, 1-546.

[0047] The morphological image of strain 41233 growing on a plate containing PDA medium is shown in the figure below. Figure 1As shown, the strain was cultured on PDA-containing plates at 28-32℃ in the dark for 30 days. The colonies were 6-7 cm in diameter, round with neat edges, and flat. They were yellowish-white in the early 7 days, brownish-yellow around day 14, and dark brown after day 30 (as shown). Figure 1 The colonies had orange exudate but no obvious pigment production.

[0048] Its microscopic morphology and structure were observed under an optical microscope, such as Figure 2 As shown: Sexual form: Unknown. Asexual form: Conidiophores solitary or in clusters, cylindrical and septate, transparent or translucent to pale brown, mostly brown at the base, cell walls gradually thinning from base to head, collar structure funnel-shaped, 1.6-2.8 μm wide, conidiophores occasionally with 1-2 coaxial conidia, mostly solitary (e.g. Figure 2 (AE diagram); spores are rarely pear-shaped, but mostly oblong-ellipsoidal, translucent to light brown, with one or two distinct hilum points on both sides of the spore (e.g., Figure 2 (F diagram), spore size length × width = (3.0-6.5) × (2.0-2.2) μm.

[0049] See (Anamorphic chaetosphaeriaceous fungi from China, Wu, WP, DiaoY.Z. Fungal Diversity, 2022, 116, 1-546.) for more information. Phaeochloridium Based on the morphological description of the genus, combined with the morphology of strain 41233, it was found that it has similar typical characteristics, but the spore size and shape are different. Therefore, it can be preliminarily identified that strain 41233 belongs to the fungus family Plectosphaerellaceae.

[0050] 3.2 DNA extraction and molecular biological identification of the strain

[0051] The purified plates were sent to Qingke Biotechnology Co., Ltd. for DNA extraction and ITS sequencing. Amplification of the fungal ITS region sequence was performed using universal primers ITS1 / ITS4.

[0052] ITS-1: 5′-TCCGTAGGTGAACCTGCGG-3′ (as shown in SEQ ID NO: 1);

[0053] ITS-4: 5′-TCCTCCGCTTAT TGATATGC-3′ (as shown in SEQ ID NO: 2).

[0054] The ITS sequence of strain 41233 is as follows:

[0055] (As shown in SEQ NO ID: 3).

[0056] The sequencing results were aligned using the NCBI (National Center for Biotechnology Information) website's Blast tool (https: / / blast.ncbi.nlm.nih.gov / Blast.cgi) to preliminarily determine the closest taxa.

[0057] 3.3 Phylogenetic Analysis

[0058] Taxonomic units with similarity within the family Plectosphaerellaceae were selected. Corresponding ITS sequences were downloaded from NCBI and aligned using the Muscle tool in MEGA X software. After pruning the aligned sequences, they were uploaded to CIPRES (https: / / www.phylo.org / ). A maximum likelihood (ML) phylogenetic tree was constructed using the RAxML-HPC BlackBox (8.2.12) program. Monilochaetes infuscans The type strain was set as an outgroup.

[0059] BLAST alignment of the ITS sequence obtained from strain 41233 showed that similar strains all belong to the family Plectosphaerellaceae, with the most similar reported taxonomic unit being [missing information]. Phaeochloridium taiwanense R. Kirschner 5374 (92.08%), similarity is much lower than the 97% threshold. Maximum likelihood tree ( Figure 3 The data shows that 41233 and... Phaeochloridium It belongs to a sister group, but the resolution of the ITS results alone is insufficient to support the construction of a new taxonomic unit. However, combined with the morphological analysis results, strain 41233 can be preliminarily identified as a new species in the family Plectosphaerellaceae.

[0060] Example 2

[0061] 1. Initial screening for activity

[0062] Pure culture of the strain and initial screening of indicator strain *Mango anthracnose* ( Colletotrichum gloeosporioides ), Phytophthora capsici ( Phytophthora capsici The samples were cultured in opposition on plates containing PDA medium at 28-32°C in the dark for 5 days, and the results were observed.

[0063] 2. Evaluation of active substances

[0064] Initial screening of strain 41233 against plate confrontation activity (e.g.) Figure 4 ), showing its resistance to Phytophthora capsici ( Figure 4 Figure A) and mango anthracnose fungus ( Figure 4 (Figure B) shows significant inhibitory activity.

[0065] Example 3

[0066] 1. Fermentation and extraction analysis of bacterial strains

[0067] 1.1 Fermentation of the strain

[0068] (1) The strain 41233 purified in Example 1 was inoculated onto a plate containing PDA medium and cultured at 28-32°C in the dark for 7 days. Then, 4×5mm bacterial blocks were taken into a 1L conical flask containing 400mL of seed culture medium and cultured at 28-32°C in the dark for 180-200rpm for 7 days to obtain the seed culture.

[0069] PDA-containing culture medium plates: 200g of peeled potatoes are boiled in 1000mL of purified water for 25min, filtered through gauze to obtain the filtrate, 20g of glucose and 20g of agar are added and fully dissolved, and then the volume is adjusted to 1000mL with purified water. The plates are then sterilized at 121℃ for 20min.

[0070] The seed culture medium is prepared by mixing 4g glucose, 4g yeast extract, and 10g malt extract, bringing the volume to 1000mL, and sterilizing at 121℃ for 20min.

[0071] (2) Solid fermentation: The seed liquid obtained in step (1) is inoculated onto rice ME solid culture medium and cultured in the dark to obtain fermentation product;

[0072] Rice ME solid medium: 110 mL of ME liquid medium is added to 1 L Erlenmeyer flasks containing 100 g of rice (10 flasks in total), and sterilized at 121 °C for 20 min to prepare for use.

[0073] The preparation method of ME liquid culture medium is as follows: 20g yeast extract, 1g peptone, 15g sucrose, and purified water are added to a final volume of 1000mL and sterilized at 121℃ for 20 minutes.

[0074] Inoculate 10 mL of seed culture into each Erlenmeyer flask containing fermentation medium and incubate at 28-32 °C in the dark for 30 days.

[0075] (3) Extraction of antibacterial active ingredients: The fermentation product obtained in step (2) was extracted three times with equal volumes of ethyl acetate under ultrasonic assistance, each time for 30 min. The extract was collected, filtered, and concentrated to remove all solvents, thus obtaining the crude extract of fungal strain 41233 from Xisha. The extract was weighed and used for later use.

[0076] 1.2 Extraction Analysis

[0077] The crude extract was dissolved in methanol to obtain a 1 mg / mL solution, which was then analyzed by high performance liquid chromatography (HPLC) under the following conditions: mobile phase: methanol / acidic water (0.1% formic acid, v / v volume percentage); mobile phase: 10%-100% methanol for 1-15 min; flow rate: 1 mL / min; column: Agilent ZORBAX Eclipse Plus C18, 4.6 × 250 mm (5 µm); instrument: Agilent 1260; fingerprint chromatogram was obtained by diode array detector (DAD).

[0078] First, a small-scale fermentation of the strain was performed, and the HPLC analysis results of the crude extract (e.g.) Figure 5 The results showed that the medium polar fraction (12-18 min) had a series of peaks with an absorption of 290 nm and abundant secondary metabolites, indicating that the fermentation conditions were suitable.

[0079] 1.3 Crude extract activity screening

[0080] Activity indicator strain: Phytophthora camphorata ( Phytophthora cinnamomi, Pc Phytophthora indicum ( Phytophthora nicotianae, Pn ), Phytophthora capsici ( Phytophthora capsici, P.ca ), Phytophthora durianis YCG1 ( Phytophthora palmivora, Pp Phytophthora palmatum BS-6 ( Phytophthora palmivora, Pp 1 ), banana anthracnose bacteria ( Colletotrichum musae, Cm Mango anthracnose fungus ( Colletotrichum gloeosporioides, Cg ), rubber anthrax bacteria GX1655 ( Colletotrichum australisinense, Ca ), rubber anthrax bacterium HBCg01 ( Colletotrichum gloeosporioides, Cg 1 ), coconut fruit rot pathogen ( Thielaviopsis paradoxa, Tp Passion fruit rot pathogen ( Diaporthe passifloricola, Dp Inhibitory activity of ).

[0081] The crude extract was dissolved in methanol to prepare a concentration of 20 mg / mL for later use. The activity re-screening was performed using the filter paper disc method; a 0.5 cm sterile filter paper disc was placed on the plate at 1 / 4 of the distance from the edge (e.g., ...). Figure 6 Add 10 μL of the prepared crude extract methanol solution to filter paper and allow it to evaporate naturally. Then, inoculate a 0.5 cm pathogenic bacterial block in the center of the plate and incubate at 28-32℃ in the dark for 5 days. For the negative control, place a filter paper disc and add 10 μL of pure methanol. Each treatment has three replicates. Use this method to evaluate the inhibition rate of the crude extract against the indicator strain. The inhibition rate is calculated using the formula below:

[0082] Inhibition rate % = [(R1–R2) / R1]×100%

[0083] Note: R1 is the diameter of the negative control colony, and R2 is the diameter of the colony in the center of the treated filter paper.

[0084] Subsequent quantitative evaluation of the crude extract showed that 20 mg / mL of the crude extract significantly inhibited the growth of *Phytophthora camphorata*, *Phytophthora tobaccotae*, *Phytophthora capsici*, *Phytophthora duriana* YCG1, *Phytophthora palmatum* BS-6, *Anthracis chinensis* (banana anthracnose fungus), *Anthracis chinensis* (mango anthracnose fungus), *Anthracis rubbera* GX1655, *Anthracis rubbera* HBCg01, *Anthracis chinensis* (coconut fruit rot fungus), and *Anthracis passionata* (passion fruit rot fungus). Figure 6 The inhibition rates are shown in Table 1 below.

[0085] Table 1. Inhibition rate of crude extract of strain 41233 against pathogens

[0086] Pathogens Inhibition rate (%) Phytophthora camphorata 47.4±3.7 Coconut fruit rot pathogen 48.5±1.1 Phytophthora indicum 47.4±4.8 Mango anthracnose fungus 45.8±1.2 Banana anthrax bacteria 66.7±1.7 Phytophthora durianis 60.1±0.8 Passion fruit rot fungus 40.7±5.2 Phytophthora palmis BS-61 18.7±1.9 GX1655, the causal agent of rubber anthrax 47.6±1.7 Rubber anthrax bacterium HBCg011 45.4±3.5 Phytophthora capsici 20.0±5.7

[0087] The results in Table 1 show that the crude extract of strain 41233 has inhibitory effects on a variety of pathogens, especially on the banana anthracnose pathogen. Cm and Phytophthora durianis Pp It has a significant inhibitory effect and has great potential for further exploration in the application of plant disease prevention and control.

[0088] It should be noted that the above embodiments are merely further illustrations of the present invention and not limitations. Any adjustments or changes made by those skilled in the art within the equivalent meaning and scope of the technical solutions of the present invention should be considered as included within the protection scope of the present invention.

Claims

1. A fungal strain 41233 from Xisha, characterized in that, The taxonomic name of the fungal strain 41233 is Plectosphaerellaceae sp . The accession number is GDMCC No. 67505, the accession date is December 19, 2025, the depositary institution is Guangdong Provincial Center for Microbial Culture Collection, the depositary address is 5th Floor, Building 59, No. 100 Xianlie Middle Road, Yuexiu District, Guangzhou, Guangdong Province, Institute of Microbiology, Guangdong Academy of Sciences.

2. The use of the fungal strain 41233 according to claim 1 in the preparation of a pathogen-inhibiting product; wherein the pathogen is *Hymenocortis mangois*. Colletotrichum gloeosporioides and / or Phytophthora capsici Phytophthora capsici .

3. A crude extract of fungal strain 41233 from Xisha, characterized in that, The crude extract was obtained by fermentation and extraction using the fungal strain 41233 described in claim 1, specifically prepared by a method comprising the following steps: (1) Seed culture: The fungal strain 41233 described in claim 1 is inoculated onto a plate containing PDA medium and cultured in the dark. The fungal block is then transferred to the seed culture medium and cultured in the dark again to obtain the seed culture. (2) Solid fermentation: The seed liquid obtained in step (1) is inoculated onto rice ME solid culture medium and cultured in the dark to obtain fermentation product; (3) Extraction of antibacterial active ingredients: The fermentation product obtained in step (2) was extracted with ethyl acetate under ultrasonic assistance. The extract was collected, filtered, and concentrated to remove all solvents, thus obtaining the crude extract of fungal strain 41233 from Xisha.

4. The crude extract of fungal strain 41233 from Xisha as described in claim 3, characterized in that, In step (1), the fungal strain 41233 was inoculated onto a plate containing PDA medium and cultured at 28-32℃ in the dark for 7 days; in step (1), the seed liquid was obtained after being cultured again at 28-32℃ at a speed of 180-200 rpm in the dark for 7 days.

5. The crude extract of fungal strain 41233 from Xisha according to claim 3, characterized in that, The inoculation amount of the seed liquid in step (2) is 4-6% of the total mass of the rice ME solid culture medium; the fermentation product is obtained after being cultured in the dark at 28-32℃ for 30 days in step (2).

6. The crude extract of fungal strain 41233 from Xisha according to claim 3, characterized in that, The fermentation product in step (3) is equal in volume to the ethyl acetate.

7. The use of the crude extract of fungal strain 41233 from Xisha as described in any one of claims 3-6 in the preparation of a pathogen-inhibiting product; wherein the pathogen is *Phytophthora camphorata*. Phytophthora cinnamomi Phytophthora indicum Phytophthora nicotianae Phytophthora durianis YCG1 Phytophthora palmivora Banana anthracnose bacteria Colletotrichum musae Mango anthracnose fungus Colletotrichum gloeosporioides GX1655, the pathogen of rubber anthrax Colletotrichum australisinense Rubber anthrax bacterium HBCg01 Colletotrichum gloeosporioides Coconut fruit rot pathogens Thielaviopsis paradoxa Passion fruit rot fungus Diaporthe passifloricola One or more of them.

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