Pseudomonas taiwanensis w178 and application thereof to preventing and treating soil-borne fungal diseases

Abstract

This application discloses a strain of *Priestia taiwanensis* W178 and its application in controlling soil-borne fungal diseases. This strain was deposited at the China Center for Type Culture Collection (CCTCC) on December 29, 2025, with accession number CCTCC NO:M 20253047. The strain exhibits significant antagonistic activity against 11 soil-borne pathogenic fungi, including *Sclerotinia sclerotiorum* and *Fusarium graminearum*, with an inhibition rate reaching up to 91.10%. This application also establishes a fermentation process for this strain, resulting in a spore count of 19.3 × 10⁻⁶ after fermentation. 8 CFU / mL. Pot experiments showed that the fermentation broth, diluted 10 times, was significantly effective in controlling rapeseed sclerotinia stem rot and could effectively inhibit the spread of lesions. This application is the first to discover the broad-spectrum biocontrol potential of *Priscilla taiwanensis* and provides an active strain and its fermentation product that can be developed into microbial agents, bio-organic fertilizers, or compound microbial fertilizers, suitable for the green control of various soil-borne fungal diseases such as rapeseed sclerotinia stem rot and wheat stem rot.

Description

Technical Field

[0001] This application relates to the field of microbial biocontrol technology, specifically to a strain of *Priestella taiwanensis* W178 and its application in controlling soil-borne fungal diseases. Background Technology

[0002] Soil-borne fungal diseases are a significant type of disease restricting agricultural production. Sclerotinia rot, caused by *Sclerotinia asclerotiorum* (Lib.) deBary, is widespread and causes severe damage to various crops such as rapeseed and soybeans, leading to yield losses of 10%-70% or even total crop failure, seriously affecting agricultural production safety. Currently, the control of sclerotinia rot mainly relies on chemical agents. However, the long-term use of chemical pesticides has obvious shortcomings: firstly, it easily leads to drug resistance in pathogens, resulting in a gradual decline in control effectiveness; secondly, it causes damage to the soil microecology, affecting the sustainable development of farmland; and thirdly, it brings the risk of pesticide residues in agricultural products, which is inconsistent with the current requirements of green agriculture development. Therefore, there is an urgent need to develop environmentally friendly, safe, and efficient biological control strategies.

[0003] Bacillus species have become a hot topic in biocontrol microbiology research due to their strong environmental adaptability, rapid reproduction, and ability to produce various antibacterial substances. *Priestia*, a new genus established in 2020 based on whole-genome phylogenetic analysis, was separated from the traditional *Bacillus* genus. Members of this genus possess both spore stability and metabolic product diversity, gradually attracting scholarly attention. Existing research shows that *Priestia megaterium* W178 is effective against various plant fungal diseases, including rice sheath blight, legume wilt, and gray mold; the fermentation broth of *Priestia aryabhattai* also shows significant control efficacy against black spot and gray mold in the traditional Chinese medicine Acanthopanax senticosus. However, since the initial report of *Priestia taiwanensis*, related research has mainly remained at the taxonomic level; its potential biocontrol functions have not been systematically evaluated, and the elucidation of its biocontrol mechanisms and the development of formulation technologies have not yet been carried out.

[0004] Therefore, the urgent technical problem to be solved is to discover a strain of *Priestella taiwanensis* with practical biocontrol potential, clarify its control effect on soil-borne fungal diseases (especially sclerotinia rot), and provide strain resources and technical support for developing new green control strategies for soil-borne crop diseases. Summary of the Invention

[0005] In view of this, the purpose of this application is to provide a strain of *Priestia taiwanensis* W178 and its application in controlling soil-borne fungal diseases. This strain was isolated and purified from soil and identified as *Priestia taiwanensis* through morphological, molecular biological, and genome sequencing analyses. This strain exhibits good control effects against soil-borne fungal diseases.

[0006] To achieve the above objectives, this application provides the following technical solution:

[0007] Firstly, this application provides a strain of *Priestia taiwanensis* W178, which was deposited on December 29, 2025, at the China Center for Type Culture Collection (CCTCC) with accession number CCTCC NO: M20253047, located at No. 299, Bayi Road, Wuchang District, Wuhan City, Hubei Province.

[0008] Secondly, this application provides a composition containing Priestia taiwanensis W178 as described in the first aspect.

[0009] Further, the composition may be a culture, which is a substance obtained by culturing *Priscilla taiwanensis* W178 or its progeny as described in the first aspect in a microbial culture medium (all substances within the culture vessel, i.e., fermentation products, such as fermentation broth containing *Priscilla taiwanensis* W178 or its progeny and substances secreted into a liquid culture medium, or solid fermentation product containing *Priscilla taiwanensis* W178 or its progeny and substances secreted into a solid culture medium). The substances in the culture include *Priscilla taiwanensis* W178 or its progeny (the bacterial cell itself) and / or its metabolites as described in the first aspect.

[0010] Furthermore, the composition can be prepared into microbial inoculants, bio-organic fertilizers, or compound microbial fertilizers.

[0011] In the aforementioned microbial inoculants, bio-organic fertilizers, or compound microbial fertilizers, the active components are *Priscilla taiwanensis* W178 or its descendants, metabolites of *Priscilla taiwanensis* W178 or its descendants, and / or cultures of *Priscilla taiwanensis* W178 or its descendants, as described in the first aspect. The active components in the microbial inoculants, bio-organic fertilizers, or compound microbial fertilizers may also contain other biological and / or non-biological components. Other active components in the microbial inoculants, bio-organic fertilizers, or compound microbial fertilizers can be determined by those skilled in the art based on the desired effect.

[0012] In addition to containing active ingredients, the aforementioned microbial agents, bio-organic fertilizers, or compound microbial fertilizers may also contain carriers acceptable in the pesticide field. These carriers are commonly used in the pesticide field and are biologically inert. The carriers can be classified morphologically as solid or liquid carriers; and morphologically as mineral materials (such as at least one of clay, talc, kaolin, montmorillonite, white carbon, zeolite, silica, and diatomaceous earth), plant materials (such as at least one of wheat flour, soybean flour, and starch), polymeric compounds (such as polyvinyl alcohol, chitosan, and polyethylene glycol), organic solvents (such as decane and / or dodecane), vegetable oils, mineral oils, or water.

[0013] Depending on the needs, surfactants (such as Tween 20, Tween 80, etc.), binders, stabilizers (such as antioxidants), pH adjusters, etc. may also be added to the above-mentioned microbial agents, bio-organic fertilizers or compound microbial fertilizers.

[0014] The formulations of the aforementioned microbial agents, bio-organic fertilizers, or compound microbial fertilizers can be of various types, such as at least one of granules, suspensions, powders, and emulsions.

[0015] In this application, the metabolites of *Priscilla taiwanensis* W178 or its progeny can be obtained from the fermentation broth of *Priscilla taiwanensis* W178 or its progeny. The metabolites of *Priscilla taiwanensis* W178 or its progeny can be sterile metabolites of *Priscilla megaterium* or its progeny, or bacterial metabolites of *Priscilla taiwanensis* W178 or its progeny. Specifically, the sterile metabolites of *Priscilla megaterium* or its progeny (sterile fermentation filtrate) can be prepared as follows: *Priscilla taiwanensis* W178 or its progeny are cultured in a liquid culture medium, and the *Priscilla megaterium* or its progeny is removed from the liquid culture (fermentation broth) by filtration, thus obtaining the sterile metabolites of *Priscilla taiwanensis* W178 or its progeny. The microbial metabolites of *Priscilla gigantea* or its progeny can be prepared by the following method: culturing *Priscilla taiwanensis* W178 or its progeny in a liquid fermentation medium, collecting the fermentation broth, which contains *Priscilla taiwanensis* W178 or its progeny and substances secreted into the liquid culture medium, is the microbial metabolites of *Priscilla taiwanensis* W178 or its progeny.

[0016] Thirdly, this application also provides a method for preparing the fermentation broth of the aforementioned *Priscilla taiwanensis* W178 or its progeny, including the steps of activating *Priscilla taiwanensis* W178 or its progeny strains, primary seed culture, fermentation in a fermenter, and obtaining the fermentation stock broth; wherein the fermentation conditions include:

[0017] The fermentation temperature was 30 ℃, and the tank pressure was 0.5 × 10⁻⁶. 5The fermentation medium formula is as follows: corn starch 1.5%, rapeseed meal 3.0%, corn syrup 1.0%, magnesium sulfate 0.1%, potassium dihydrogen phosphate 0.1%, dipotassium hydrogen phosphate 0.1%, ammonium chloride 0.1%, ferrous sulfate 0.002%, calcium carbonate 0.3%, and the medium pH is 7.5.

[0018] Fourthly, this application provides the use of the *Priestella taiwanensis* W178 described in the first aspect or the composition described in the second aspect in the prevention and control of soil-borne fungal diseases.

[0019] In some preferred embodiments, the soil-borne fungal disease is sclerotinia stem rot of rapeseed and / or stem base rot of wheat.

[0020] In some embodiments, the pathogen of rapeseed sclerotinia rot is *Sclerotinia sclerotiorum*; and the pathogen of wheat stem rot is *Fusarium graminearum* and / or *Fusarium pseudograminearum*.

[0021] Fifthly, this application provides the use of the *Priscilla taiwanensis* W178 described in the first aspect or the composition described in the second aspect in the preparation of drugs for the prevention and treatment of soil-borne pathogenic fungi.

[0022] In some preferred embodiments, the soil-borne pathogenic fungus includes at least one of Botrytiscinerea, Fusarium oxysporum, Phytophthora capsici, Rhizoctonia solani AG-1 (rice sheath blight), Rhizoctonia solani AG-8 (wheat sheath blight), Fusarium solani (soybean rot), Sclerotium rolfsii (peanut white rot), and Fusarium neocosmosporiellum (peanut fruit rot).

[0023] Compared with the prior art, this application has at least the following beneficial effects:

[0024] 1. This application provides a novel strain of *Priestia taiwanensis* with biocontrol potential. This strain, W178, was isolated from the rhizosphere soil of healthy rapeseed plants in a severely diseased rapeseed field in Jiangxia District, Wuhan City, Hubei Province. Through morphological observation, physiological and biochemical characterization, 16S rDNA sequence analysis, and whole-genome sequencing (including ANI analysis), it was identified as *Priestia taiwanensis*. Whole-genome functional gene annotation was completed (a total of 4397 functional genes were predicted), providing a strain resource and genetic information basis for subsequent research on biocontrol mechanisms.

[0025] 2. The Taiwan Priestella W178 strain provided in this application exhibits broad-spectrum antagonistic activity against a variety of soil-borne pathogenic fungi. Using the plate confrontation method, strain W178 showed significant antagonistic activity against 11 soil-borne pathogenic fungi, including *Sclerotinia sclerotiorum*, *Fusarium graminearum*, *Fusarium pseudograminearum*, *Botrytis cinerea*, *Fusarium oxysporum*, *Phytophthora capsici*, *Rhizoctonia solani AG-1*, *Rhizoctonia solani AG-8*, *Fusarium solani*, *Fusarium neocosmosporiellum*, and *Sclerotium rolfsii*, with the highest inhibition rate reaching 91.10%. This application is the first to demonstrate the broad-spectrum biocontrol potential of *Priscilla taiwanensis*.

[0026] 3. This application establishes a fermentation process for *Priscilla taiwanensis* W178 and demonstrates its control effect on sclerotinia stem rot in rapeseed. This application establishes for the first time a large-scale fermentation process (50 L fermenter) for *Priscilla taiwanensis* W178, and determines the fermentation medium formula and culture conditions (temperature 30 ℃, tank pressure 0.5 × 10⁻⁶). 5 (Pa, pH 7.5, etc.) After fermentation, the number of spores reached 19.3 × 10⁻⁶. 8 CFU / mL. Pot experiments showed that spraying with a 10-fold dilution of the fermentation stock solution significantly inhibited the spread of Sclerotinia sclerotiorum on rapeseed leaves. The leaves in the treatment group were upright and showed almost no lesions, while the leaves in the control group rotted and collapsed over a large area, demonstrating good in vivo control efficacy. This strain can be further developed into a microbial fungicide.

[0027] Instructions for strain preservation:

[0028] Classification and nomenclature: Priestia taiwanensis W178;

[0029] Preservation institution: China Center for Type Culture Collection;

[0030] Preservation institution code: CCTCC;

[0031] Address of the depository: No. 299, Bayi Road, Wuchang District, Wuhan City, Hubei Province;

[0032] Deposit date: December 29, 2025;

[0033] The accession number is CCTCC NO: M 20253047. Attached Figure Description

[0034] Figure 1 The images show the colony morphology and Gram staining results of *Priscilla taiwanensis* W178 provided in Example 1 of this application, where A represents the colony morphology and B represents the Gram staining results.

[0035] Figure 2 Phylogenetic tree of *Primatecium taiwanense* W178 provided in Example 1 of this application.

[0036] Figure 3 The genome map of strain W178 provided in Example 2 of this application.

[0037] Figure 4 The results of a pot experiment on the control of rapeseed sclerotinia stem rot with fermentation broth provided in Example 5 of this application. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0039] The materials used in the following embodiments are not limited to those listed below, and other similar materials may be used instead. Unless otherwise specified, the instruments shall be used under conventional conditions or as recommended by the manufacturer. Those skilled in the art should have relevant knowledge of the use of conventional materials and instruments.

[0040] In this application, unless the context clearly indicates otherwise, the terms “including,” “comprising,” “containing,” “having,” etc., shall be understood as open-ended and mean “including but not limited to.”

[0041] To better understand this teaching and without limiting its scope, all figures and other numerical values ​​used in the specification and claims to express quantities, percentages, or proportions should, in all cases, be understood to be modified by the term "about." Therefore, unless otherwise stated, the numerical parameters set forth in the following specification and appended claims are approximate values ​​that may vary depending on the desired properties sought. At a minimum, each numerical parameter should be interpreted based at least on the reported significant figures and by applying common rounding techniques.

[0042] Unless otherwise specified, in this application, "%" represents mass fraction when indicating concentration.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the subject matter of this application pertains. Before providing a detailed description of this application, the following terms and definitions are provided to better understand this application:

[0044] 1. Metabolites: These refer to the primary and / or secondary metabolites produced during microbial metabolism. Primary metabolism refers to the process by which microorganisms absorb various nutrients from the external environment and generate substances and energy to sustain life activities through catabolism and anabolism. The products of primary metabolism are called primary metabolites, such as monosaccharides or monosaccharide derivatives, nucleotides, vitamins, amino acids, fatty acids, and various macromolecular polymers composed of them, such as proteins, nucleic acids, polysaccharides, and lipids. Secondary metabolism refers to the process by which microorganisms, during a certain growth stage, use primary metabolites as precursors to synthesize substances that have no clear function for their life activities. The products of secondary metabolism are called secondary metabolites, and most are compounds with relatively complex molecular structures. Based on their functions, they can be classified into antibiotics, hormones, alkaloids, toxins, etc.

[0045] 2. Culture: Refers to any liquid or solid culture medium that has grown a microbial community after artificial inoculation and cultivation. It is the product obtained through the growth and / or amplification of microorganisms. It can be a biologically pure culture of microorganisms, or it can contain a certain amount of culture medium, metabolites, or other components produced during the cultivation process. The term "culture" also includes passaged cultures obtained by subculturing microorganisms; these can be cultures of a single generation or a mixture of several generations.

[0046] The following are specific examples:

[0047] Example 1: Isolation and Identification of Strains

[0048] 1.1 Isolation and Purification of Strains

[0049] Strain W178 was isolated from healthy rapeseed rhizosphere soil from a severely diseased rapeseed field in Jiangxia District, Wuhan City, Hubei Province. Pure cultures were obtained using conventional soil microbial isolation techniques, including dilution plating and streak plating. Single colonies were purified three times and then stored at -80 °C with glycerol at a final concentration of 20% (v / v).

[0050] 1.2 Morphological observation

[0051] Strawberry strain W178 was streaked onto LB agar plates (tryptone 10 g / L, yeast extract 5 g / L, NaCl 10 g / L, agar 10 g / L), and incubated at 30 °C for 24 h. Colony morphology was then observed. Figure 1 Colonies of type A are milky white, round, with regular edges and a smooth surface. Gram staining results are as follows: Figure 1 As shown in Figure B, the Gram staining micrograph of strain W178 is purple, and strain W178 has been identified as a Gram-positive bacterium.

[0052] 1.3 Determination of physiological and biochemical characteristics

[0053] The physiological and biochemical characteristics of strain W178 were determined with reference to the "Handbook of Systematic Classification and Identification of Common Bacteria and Archaea". The results are shown in Table 1, where "+" indicates positive or usable, and "-" indicates negative or unusable.

[0054] Table 1. Physiological and biochemical characteristics of strain W178

[0055]

[0056] As shown in Table 1, the growth temperature range of strain W178 is 20–40 ℃, with an optimal growth temperature range of 30–37 ℃. Strain W178 can utilize glucose, maltose, and starch to produce acid, but cannot utilize L-arabinose, lactose, fructose, and sucrose. The strain showed positive results in both organic and inorganic phosphorus utilization tests, indicating that it can utilize organic and inorganic phosphorus as phosphorus sources required for growth. The salt tolerance test, gelatin hydrolysis test, indole production test, VP test, nitrate reduction test, and cellulose decomposition test were all negative.

[0057] 1.4 Molecular Identification of 16S rDNA

[0058] Strain W178 was inoculated into LB liquid medium (10 g / L tryptone, 5 g / L yeast extract, 10 g / L NaCl) and cultured at 30 ℃ and 200 rpm for 24 h. Bacterial genomic DNA was extracted using an extraction kit (Beijing Tiangen Biotech Co., Ltd., catalog number DP302-02) according to the manufacturer's instructions. Using the purified genomic DNA as a template, PCR amplification was performed using universal primers for bacterial 16S rDNA. The primer sequences are as follows:

[0059] Forward primer 27F: AGAGTTTGATCMTGGCTCAG (SEQ ID NO:2);

[0060] Reverse primer 1492R:TACGGYTACCTTGTTACGACTT (SEQ ID NO:3).

[0061] The PCR product was sequenced (sequencing was performed by Wuhan Jinkairui Biotechnology Co., Ltd.), and the resulting sequence was 1424 bp in length. Its nucleotide sequence is shown in SEQ ID NO:1.

[0062] 16S rDNA sequence of strain W178 (SEQ ID NO:1):

[0063]

[0064] NCBI BLAST comparison showed that this sequence had the highest similarity (100%) to the type strain of *Priestia taiwanensis* FJAT-14571 (accession number NR_136461.1). A phylogenetic tree was constructed using PhyML (v3.1) with the nearest neighbor method, and the results are as follows: Figure 2 As shown in the figure, strain W178 is most closely related to *Priscilla taiwanensis*.

[0065] Based on the combined morphological, physiological and biochemical characteristics and 16S rDNA sequence analysis results, strain W178 was preliminarily identified as *Priestia taiwanensis*.

[0066] Example 2: Whole Genome Sequencing Identification and Analysis

[0067] 2.1 Whole Genome Sequencing and Assembly

[0068] Genomic DNA was extracted from strain W178, and whole-genome sequencing was performed using the PacificBiosciences Sequel II third-generation sequencing platform by Shanghai Lingen Biotechnology Co., Ltd. The raw data were sequenced, pruned, and quality-controlled using Trimmomatic software to obtain clean data for subsequent analysis. Long reads were converted to FASTA format using Samtools, and genome complexity was assessed using next-generation high-throughput sequencing (NGS) data, with long reads corrected. The strain's genome was assembled using Unicycler software, and the optimal assembly results were selected.

[0069] Analysis revealed that the full-length genome of strain W178 is approximately 38,992,576 bp, with a GC content of 37.49% and zero unknown bases (N). The genome map is shown below. Figure 3 As shown.

[0070] 2.2 Average Nucleotide Identity (ANI) Analysis

[0071] Whole-genome alignment analysis of strain W178 with the reference strain *Priestia taiwanensis* DSM-27845 was performed using the JSpecies WS online tool (http: / / jspecies.ribohost.com / jspeciesws). The ANI value was calculated using the ANIm algorithm. The results showed that the ANIm value of the two strains was 99.01% (ANI ≥ 95% indicates the same species), and the homologous sequence coverage was 92.98%. Based on morphological and physiological characteristics and 16S rDNA identification results, strain W178 was finally identified as *Priestia taiwanensis*.

[0072] 2.3 Functional gene annotation

[0073] Based on the assembled genome data, a gene prediction strategy based on the ab initio algorithm was employed, and GeneMark software was used to identify and predict protein-coding genes. All predicted protein sequences were aligned with various functional databases using BLASTP to complete gene functional annotation. The databases involved included: NCBI Non-Redundant Protein Database (NR), UniProt, Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene Ontology (GO), Codon Orthologs (COG), Carbohydrate Active Enzymes Database (CAZy), and Comprehensive Antibiotic Resistance Database (CARD).

[0074] Statistical analysis revealed that strain W178's genome contained 4397 functional genes with a total length of 355.36 kbp. The GC content of the gene regions was 38.0%, accounting for 85.2% of the total genome length. 4397 proteins were predicted to be encoded. Alignment of these protein sequences with various databases yielded the following numbers of functional proteins: NR (4123), GO (942), eggNOG (3113), KEGG (2055), UniProt (2534), CAZy (102), and CARD (131).

[0075] 2.4 Non-coding RNA Analysis

[0076] RNAmmer-1.2 and tRNAscan-SE 2.0.4 software were used to identify and annotate the rRNA and tRNA contained in the genome. Statistical analysis predicted a total of 103 tRNAs, 12 5S rRNAs, 12 16S rRNAs, and 12 23S rRNAs in the genome of strain W178.

[0077] Example 3: Determination of antagonistic activity of strain W178

[0078] 3.1 Test pathogenic fungi

[0079] The pathogenic fungi used in this embodiment were all isolated and preserved by the inventors' team of this application, including: *Sclerotinia sclerotiorum*, *Botrytis cinerea*, *Pestalotiopsis theae*, *Fusarium oxysporum*, *Phytophthora capsici*, *Rhizoctonia solani AG-1*, *Rhizoctonia solani AG-8*, *Fusarium solani*, *Sclerotium rolfsii*, *Fusarium neocosmosporiellum*, *Fusarium graminearum*, and *Fusarium pseudograminearum*.

[0080] 3.2 Flat Plate Standoff Method

[0081] Strain W178 was activated on LB agar plates (10 g / L tryptone, 5 g / L yeast extract, 10 g / L NaCl, 10 g / L agar) (30 °C for 24 h). Simultaneously, the tested fungi were inoculated onto PDA agar plates (200 g / L potato soaked and filtered through gauze, 20 g / L glucose, 10 g / L agar) and activated at 28 °C for 3–7 days. Mycelial cakes were punched at the edge of the fungal colonies using a 5 mm diameter punch and inoculated onto new PDA agar plates (90 mm diameter) approximately 3 cm from the center. Simultaneously, 5 mm diameter sterile filter paper discs were placed symmetrically. Freshly cultured W178 culture (OD) was collected. 600 (Approximately 1.0 μL, adjusted with sterile water) 3-5 μL was added to filter paper. Sterile LB broth was added as a control. Each treatment was repeated in triplicate. The culture was incubated at 28 ℃ for 3–7 days (until the control colonies fully colonized the plate). The diameter of the pathogenic fungal colonies was observed and measured, and the inhibition rate was calculated using the following formula:

[0082]

[0083] 3.3 Antagonistic Activity Results

[0084] Statistical analysis showed that the antagonistic activity (mean ± standard deviation) of strain W178 against different pathogenic fungi was as shown in Table 2.

[0085] Table 2. Antagonistic activity of strain W178 against various soil-borne pathogenic fungi.

[0086]

[0087] The results showed that strain W178 had varying degrees of antagonistic activity against the above 11 soil-borne pathogenic fungi, with the highest inhibition rate against wheat sheath blight, reaching 91.10%; the inhibition rates against rice sheath blight, Fusarium oxysporum, and Fusarium graminearum all exceeded 70%.

[0088] Example 4: Preparation of fermentation broth for strain W178

[0089] 4.1 Activation of microbial strains

[0090] The Taiwan Priestella W178 strain, preserved in glycerol tubes at -80 °C, was inoculated onto LB agar slants (10 g / L tryptone, 5 g / L yeast extract, 10 g / L NaCl, 10 g / L agar) and activated at 30 °C for 48 h.

[0091] 4.2 Primary Seed Culture

[0092] Primary seed culture medium formulation (mass fraction, balance water): glucose 1.0%, beef extract 1.0%, peptone 1.0%, sodium chloride 0.5%, pH 7.0. Add 100 mL of primary seed culture medium to a 500 mL Erlenmeyer flask and sterilize at 121 °C for 30 min. Inoculate the activated W178 strain culture into the primary seed culture medium and incubate at 30 °C and 200 r / min for 10 h to obtain the primary seed solution.

[0093] 4.3 Fermentation in fermentation tanks

[0094] Fermentation medium formula (mass fraction, balance being water): corn starch 1.5%, rapeseed meal 3.0%, corn syrup 1.0%, magnesium sulfate 0.1%, potassium dihydrogen phosphate 0.1%, dipotassium hydrogen phosphate 0.1%, ammonium chloride 0.1%, ferrous sulfate 0.002%, calcium carbonate 0.3%, pH 7.5. The defoamer was THI®X-298, purchased from Yantai Hengxin Chemical Co., Ltd., Shandong Province.

[0095] Add 30 L of fermentation medium and 30 mL of antifoaming agent THI®X-298 to a 50 L fermenter, and sterilize at 121 ℃ for 30 min. When the fermenter temperature drops to 32 ℃, inoculate with 50 mL of the primary seed culture prepared in step 4.2. Fermentation conditions: fermenter pressure 0.5 × 10⁻⁶. 5 The culture temperature was 30 °C. After 34 h of fermentation, samples were taken every 2 h for microscopic examination. Fermentation was stopped when 20% of the spores were detached and separated.

[0096] 4.4 Fermentation stock solution

[0097] The number of spores at the end of fermentation was 19.3 × 10⁻⁶. 8 The fermentation broth obtained at CFU / mL is the fermentation stock solution, which is used in the following examples.

[0098] Example 5: Pot Experiment on the Control of Sclerotinia sclerotinia in Rapeseed Using Fermentation Broth

[0099] 5.1 Test Materials

[0100] Fermentation stock broth: Fermentation stock broth of *Priscilla taiwanensis* W178 prepared in Example 4.

[0101] The test crop was rapeseed, variety "Huashuang No. 4", which was purchased through an online seed distribution platform.

[0102] The tested pathogen was *Sclerotinia sclerotiorum*, which was isolated and preserved by the inventors' team.

[0103] Nutrient soil: Seedling substrate for budding plants, Jiangsu Budding Substrate Technology Development Co., Ltd.

[0104] 5.2 Test Methods

[0105] Rapeseed seedling raising: Place rapeseed seeds on moistened filter paper and incubate in the dark at 20 ℃ to promote germination. After emergence, transplant seedlings into pots filled with nutrient soil and place them in a light incubator with 16 hours of light (light intensity 200 μmol / m²). 2 / s) / 8 h in darkness, temperature 20 ℃, culture for 4–6 weeks.

[0106] Inoculation and Treatment: Select rapeseed seedlings with uniform growth and transfer them to a humidity-controlled container (relative humidity ≥90%). Use a 5mm diameter punch to collect mycelial cakes from the edge of *Sclerotinia sclerotiorum* PDA agar colonies and inoculate the mycelial cakes onto the surface of rapeseed leaves (one mycelial cake per leaf, 2–3 leaves per plant). The treatment group was sprayed with a 10-fold diluted solution of the fermentation stock solution prepared in Example 4 (approximately 1 mL per leaf), while the control group was sprayed with an equal volume of sterile water. Each treatment consisted of 3 pots (3 plants per pot), and was repeated 3 times.

[0107] Cultivation and observation: Place the inoculated rapeseed seedlings in the same light incubator and keep them moist for 2-3 days to observe the disease status of the rapeseed leaves.

[0108] 5.3 Test Results

[0109] like Figure 4As shown, in the control group (sprayed with sterile water), rapeseed leaves exhibited extensive rot and collapse, with lesions expanding rapidly and leaf tissue completely collapsing. In contrast, the treatment group (sprayed with diluted W178 fermentation broth) showed upright leaves with only slight brown necrosis around the inoculation point and almost no expanding lesions. The results indicate that the Taiwan Priestella W178 fermentation broth significantly inhibited the infection and spread of Sclerotinia sclerotiorum on living rapeseed plants, demonstrating a good control effect against rapeseed sclerotinia rot.

[0110] The present application has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present application. The descriptions of the embodiments above are only for the purpose of helping to understand the present application and its core ideas. It should be noted that those skilled in the art can make several improvements and modifications to the present application without departing from the principles of the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.

Claims

1. A strain of *Priestia taiwanensis* W178 was deposited on December 29, 2025, at the China Center for Type Culture Collection (CCTCC) with accession number CCTCC NO:M 20253047, located at No. 299, Bayi Road, Wuchang District, Wuhan City, Hubei Province.

2. A composition containing the *Priscilla taiwanensis* W178 as described in claim 1.

3. The composition according to claim 2, wherein the composition is a culture obtained by culturing the *Priscilla taiwanensis* W178 or its progeny as described in claim 1 in a microbial culture medium.

4. The composition according to claim 2 or 3 can be used to prepare microbial inoculants, bio-organic fertilizers or compound microbial fertilizers, wherein the dosage form of the microbial inoculants, bio-organic fertilizers or compound microbial fertilizers is at least one of granules, suspensions, powders or emulsions.

5. The method for preparing the fermentation broth of *Priscilla taiwanensis* W178 or its progeny according to claim 1, comprising the steps of activating *Priscilla taiwanensis* W178 or its progeny strains, primary seed culture, fermentation in a fermenter, and obtaining the fermentation stock broth; wherein, Fermentation conditions include: The fermentation temperature was 30 ℃, and the tank pressure was 0.5 × 10⁻⁶. 5 The fermentation medium formula is as follows: corn starch 1.5%, rapeseed meal 3.0%, corn syrup 1.0%, magnesium sulfate 0.1%, potassium dihydrogen phosphate 0.1%, dipotassium hydrogen phosphate 0.1%, ammonium chloride 0.1%, ferrous sulfate 0.002%, calcium carbonate 0.3%, and the medium pH is 7.

5.

6. The use of the *Priestella taiwanensis* W178 of claim 1 or the composition of claim 2 in the prevention and control of soil-borne fungal diseases.

7. The application according to claim 6, wherein the soil-borne fungal disease is sclerotinia rot of rapeseed and / or stem base rot of wheat.

8. The application according to claim 7, wherein the pathogen of rapeseed sclerotinia stem rot is *Sclerotinia sclerotiorum*; and the pathogen of wheat stem rot is *Fusarium graminearum* and / or *Fusarium pseudograminearum*.

9. The use of the *Priestella taiwanensis* W178 as described in claim 1 or the composition as described in claim 2 in the preparation of a drug for the prevention and control of soil-borne pathogenic fungi.

10. The application according to claim 9, wherein the soil-borne pathogenic fungus includes at least one of Botrytis cinerea, Fusarium oxysporum, Phytophthora capsici, Rhizoctonia solani, Rhizoctonia solani, Solanum rot, Sclerotium arachnoides, and Pterocaryonium arachnoides.

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