A small molecule inhibitor targeting the Phytophthora sterol-sensing receptor SSRK1 and its application

Abstract

This invention discloses a small-molecule inhibitor targeting the sterol-sensing receptor SSRK1 of *Phytophthora indicum* and its application, belonging to the field of pesticide biotechnology. This inhibitor specifically binds to the sterol-binding site of SSRK1, competitively blocking natural sterol signaling, thereby achieving comprehensive inhibition of *Phytophthora indicum* growth, development, and pathogenicity. The compound exhibits significant antifungal activity against various *Phytophthora indicum* species (such as *Phytophthora indicum*, *Phytophthora indicum* var. *pathogenica*, and *Phytophthora indicum* var. *petifolia*), effectively controlling crop diseases such as soybean root rot, potato late blight, and pepper blight. The small-molecule inhibitor provided by this invention features novel targets, unique mechanisms of action, broad-spectrum efficacy, and environmental friendliness, and is less prone to cross-resistance with traditional fungicides, providing a new candidate molecule and formulation development pathway for the green control of *Phytophthora indicum*.

Description

Technical Field

[0001] This invention belongs to the field of pesticide biotechnology and plant protection, specifically relating to a specific small molecule inhibitor targeting the sterol-sensing receptor SSRK1 of Phytophthora infestans, and the application of this inhibitor in inhibiting the growth and development of Phytophthora infestans and preventing related plant diseases. Background Technology

[0002] Phytophthora are important plant pathogens, with more than 200 known species. They can infect a variety of food and cash crops, causing serious plant diseases and resulting in significant economic losses to global agriculture. For example, *Phytophthora sojae* can cause root rot in soybeans, which can lead to yield reductions of more than 30% or even total crop failure, greatly threatening the safe, green, and efficient production of soybeans (Chepsergon J, Motaung TE, Bellieny-Rabelo D, Moleleki LN. Organize, Don't Agonize: Strategic Success of Phytophthora Species. Microorganisms. 2020, 8:917.).

[0003] Although Phytophthora resembling fungi are morphologically similar, it belongs to the phylum Oomycetes, not fungi, making it ineffective against many common fungicides. Furthermore, Phytophthora's complex genetic diversity, strong genomic plasticity, and rapid natural variation make it prone to developing drug-resistant strains and overcoming host resistance, further complicating its control. Therefore, there is an urgent need to develop novel, efficient, and safe control methods.

[0004] Sterols are essential organic compounds in organisms, playing a crucial role in fungal-host interactions. Their synthetic pathways have long been a primary target in the development of fungicides, driving the development of allylamine, triazole, and polyene antifungal drugs (Kazan, K., and Gardiner, DM. Targeting pathogen sterols: Defence and counterdefence PLoS Pathog. 2017, 13:e1006297.). However, *Phytophthora* is a sterol heterotroph, unable to synthesize sterols itself and must acquire them from the host during infection. Therefore, interfering with the sterol sensing and utilization pathways of *Phytophthora* could provide a novel and difficult-to-overcome target for controlling this fungus. SSRK1 (Sterol-SensingReceptor Kinase 1) is a core receptor we recently discovered that mediates the sensing of exogenous sterols in *Phytophthora* (Pei Y, JiP, Miao J, Gu X, Wang H, Zhao Y, Song W, Guo Z, Zhou H, Shen D, Liu J, Si J, Yan J, Ren Y, Bao Y, Yin Z, Dou D. A receptor kinase senses sterol by coupling with elicitins in auxotrophic *Phytophthora*. Proc Natl Acad Sci U SA. 2024, 121:e2408186121.). Blocking this receptor and its signaling pathway is an important direction for developing novel, highly effective, and low-toxicity fungicides. Summary of the Invention

[0005] The purpose of this invention is to provide a small molecule inhibitor targeting the sterol-sensing receptor SSRK1 of *Phytophthora infestans* and its application. This inhibitor is a small molecule compound that specifically binds to the SSRK1 sterol binding site, thereby comprehensively inhibiting the pathogenicity and reproductive capacity of *Phytophthora infestans* by blocking sterol signal transduction.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] In a first aspect, the present invention provides the use of a small molecule inhibitor of Phytophthora sterol receptor SSRK1, as shown in formula (I), in the following (a) or (b) or (c) or (d):

[0008] (a) Application in inhibiting the growth and development of Phytophthora;

[0009] (b) Use in the preparation of products for inhibiting the growth and development of Phytophthora;

[0010] (c) Application in the prevention and control of plant diseases caused by Phytophthora;

[0011] (d) Use in the preparation of products for the prevention and control of plant diseases caused by Phytophthora;

[0012] (I).

[0013] Furthermore, the small molecule inhibitors described herein are applied exogenously to the target plants to prevent and control plant diseases caused by Phytophthora.

[0014] In a second aspect, the present invention provides a pesticide composition in which the active ingredient comprises the aforementioned small molecule inhibitor.

[0015] Furthermore, the active ingredient also includes at least one of fluthiazopyr acetophenone, metalaxyl-M, and fludioxonil.

[0016] Furthermore, the pesticide composition is formulated from the active ingredient and pesticide excipients into a pesticide-permitted formulation, such as a wettable powder, water-dispersible granule, suspension concentrate, emulsifiable concentrate, or aqueous solution.

[0017] Thirdly, the present invention provides a method for inhibiting the growth and development of Phytophthora, comprising applying an effective amount of the aforementioned small molecule inhibitor or the aforementioned pesticide composition to Phytophthora or its growth environment.

[0018] Fourthly, the present invention provides a method for preventing and controlling Phytophthora blight, comprising applying an effective amount of the aforementioned small molecule inhibitor or the aforementioned pesticide composition to the target plant or the target plant's growing environment.

[0019] In the technical solution of this invention, the Phytophthora is at least one of Phytophthora sojae, Phytophthora infestans, and Phytophthora capsici; the plant is any one of soybean, potato, and chili pepper.

[0020] In this invention, the plant disease is Phytophthora in soybeans, potatoes, or peppers, caused by at least one of Phytophthora soybeani, Phytophthora pathogenica, and Phytophthora capsici. Specifically, the Phytophthora disease includes, but is not limited to, at least one of soybean root rot, potato late blight, and pepper blight.

[0021] This invention screens a small molecule compound that specifically binds to the sterol-binding pocket of the Phytophthora SSRK1 protein, competitively inhibiting the binding of sterols to SSRK1, thereby interfering with the sterol signaling of Phytophthora and inhibiting mycelial growth, zoospore and oospore production. This small molecule compound is compound 7 (structure shown in formula (I)) obtained through virtual screening. This compound is a commercially available product supplied by Enamine.

[0022] In the applicant's previous related research (see: Pei Y, Ji P, Miao J, Gu X, Wang H, Zhao Y, Song W, Guo Z, Zhou H, Shen D, Liu J, Si J, Yan J, Ren Y, Bao Y, Yin Z, Dou D. A receptor kinase senses sterol by coupling with elicitins inauxotrophic Phytophthora. Proc Natl Acad Sci US A. 2024, 121:e2408186121.), phylogenetic analysis revealed that the homologous protein of SSRK1 exists in all the oomycetes studied and forms an independent branch in the dendritic structure of all LRR-RLK. Oomycetes are a group of filamentous eukaryotes that are morphologically similar to fungi but are more closely related to brown algae and diatoms. Phytophthora is the largest pathogenic genus among oomycetes. In this study, the applicant performed cross-species alignments of the amino acid sequence of the SSRK1 extracellular domain (a key region for ligand binding). The analysis covered 12 representative Phytophthora species: *Phytophthora sojae*, *Phytophthora infestans*, *Phytophthora capsici*, *Phytophthora cinnamomi*, *Phytophthora palmivora*, *Phytophthora ramorum*, *Phytophthora aleatoria*, *Phytophthora idaei*, *Phytophthora cactorum*, *Phytophthora boehmeriae*, *Phytophthora pseudosyringae*, and *Phytophthora kernoviae*. The analysis results showed that the SSRK1 extracellular domain of the above 12 Phytophthora species had a similarity of over 80% with the sequence shown in SEQ ID NO:2, and some even exceeded 90%. This indicates that SSRK1 (SEQ ID NO:2) is highly conserved and widely distributed within the genus Phytophthora, and inhibitors designed based on this conserved target have highly predictable inhibitory effects on each Phytophthora species.

[0023] The beneficial effects of this invention are:

[0024] This invention achieves a "source cutoff" of pathogenic signals by targeting the SSRK1 receptor, a core receptor for exogenous sterols in *Phytophthora*. This inhibitor specifically occupies the receptor binding pocket, competitively blocking sterol-induced calcium signaling and MAPK activation, fundamentally interfering with the growth and reproduction processes of *Phytophthora*. Because this receptor is highly conserved in the *Phytophthora* genus and has no homologous genes in higher plants and animals, this inhibitor exhibits excellent broad-spectrum control efficacy and biosafety, providing a novel molecular strategy for addressing the problem of resistance to traditional fungicides. Attached Figure Description

[0025] Figure 1 This document presents a virtual screening process and preliminary screening results for inhibitors targeting the SSRK1 sterol binding site. A shows the 3D structure of the SSRK1 extracellular domain predicted by AlphaFold3, with the yellow areas indicating key sterol binding sites Y263 and T265. B shows the virtual screening process targeting the SSRK1 extracellular domain (compound library screening, drug-likeness screening, molecular docking, fingerprint similarity analysis, and interaction site analysis). C shows the inhibition rate of the top 10 compounds by docking score against wild-type Phytophthora bean.

[0026] Figure 2 The expression, purification, and binding activity verification of SSRK1 protein with compounds 5, 6, and 7 were performed. A shows the binding affinity of the SSRK1 extracellular domain to compound 5 determined by the MST method; B shows the binding affinity of the SSRK1 extracellular domain to compound 6 determined by the MST method; C shows the binding affinity of the SSRK1 extracellular domain to compound 7 determined by the MST method; and D shows a virtual docking diagram of compound 7 and the SSRK1 extracellular domain.

[0027] Figure 3 This provides experimental verification of the competitive inhibition of SSRK1 binding to the natural ligand β-sitosterol by compound 7.

[0028] Figure 4 To verify the biological activity of compound 7 against Phytophthora sacchariformis and its SSRK1 dependence, including the inhibition of sterol-induced zoospore formation and oospore production; where A represents the effect of compound 7 on zoospore production in wild-type and ssrk1 mutant Phytophthora sacchariformis; and B represents the effect of compound 7 on oospore production in wild-type and ssrk1 mutant Phytophthora sacchariformis.

[0029] Figure 5 The in vitro protective effects of compound 7 against late blight of soybean, potato, and pepper are shown. Among them, A represents the in vitro protective effect of compound 7 against soybean root rot; B represents the in vitro protective effect of compound 7 against potato late blight; and C represents the in vitro protective effect of compound 7 against pepper blight. Detailed Implementation

[0030] The present invention will now be described in detail with reference to the specific embodiments shown in the accompanying drawings. However, these embodiments do not limit the present invention, and any structural, methodological, or functional modifications made by those skilled in the art based on these embodiments are included within the scope of protection of the present invention.

[0031] Example 1: Virtual screening process and initial screening results for inhibitors targeting the SSRK1 sterol binding site.

[0032] Step 1) Establishment and preprocessing of target protein model

[0033] First, the amino acid sequence of the extracellular domain of the soybean phytophthora sterol receptor protein SSRK1 was obtained, and its three-dimensional structure was predicted using AlphaFold3. The protein model was then hydrogenated, dehydrated, and optimized using Pymol software, and the ligand-binding pocket (grid box) was determined based on known sterol binding sites (see [link to Pytophthora sterol receptor protein SSRK1]). Figure 1 (A in the middle).

[0034] Step 2) Preparation of the compound database

[0035] The MCE (MedChemExpress) small molecule database, containing approximately 3 million compounds, was selected. LigPrep was used to perform high-energy state transitions, chiral isomer generation, and ionization at neutral pH on the small molecules, generating a suitable 3D conformation library for docking.

[0036] Step 3) Tiered virtual screening process (corresponding process) Figure 1 (B)

[0037] This invention employs a funnel-style screening strategy, with the following specific steps: (1) First, approximately 300,000 candidate compounds are obtained by preliminary filtering based on the physicochemical properties of pesticide-like molecules from a database containing 3,000,000 candidate molecules. The screening criteria are strictly set as 150≤MW≤500; logP≤6; HBD≤3; HBA≤12; RB≤12; (2) After eliminating molecules unsuitable as pesticide lead compounds through this physicochemical property evaluation, the remaining molecules are docked to the sterol-binding pocket of the SSRK1 protein using software. Based on the docking energy score, the top 10% of 30,000 compounds were selected for the next round of screening; (3) In order to ensure the structural diversity of candidate molecules and avoid the risks of existing patents, this invention further uses the ECFP-4 molecular fingerprint similarity algorithm for cluster analysis, removes molecules with highly redundant structures, and selects 100 compounds with representative skeletons; (4) Finally, based on the core functional site Y263 residue of SSRK1 sensing sterol, molecules that can form hydrogen bonds or π-π stacking interactions with Y263 and form hydrophobic interactions with pockets are selected. The 10 final candidate compounds (final concentration of 100 μM) were initially screened for inhibiting the growth of soybean mycelium, and compounds 5, 6, and 7 were identified as preliminary candidates (see Figure 1 (C in the table). The structural formulas of compounds 5, 6, and 7 are shown in Table 1. All compounds 5, 6, and 7 were purchased from Enamine.

[0038] Table 1. Structural formulas of compounds 5, 6, and 7

[0039]

[0040] Example 2: Expression, purification, and binding activity verification of SSRK1 protein with compounds 5, 6, and 7.

[0041] Using cDNA obtained by reverse transcription of total RNA from *Phytophthora sojae* as a template, primers (upstream primer shown in SEQ ID NO:3, downstream primer shown in SEQ ID NO:4) were designed based on the nucleotide sequence of the extracellular region of SSRK1 shown in SEQ ID NO:1 (the amino acid sequence encoding the protein is shown in SEQ ID NO:2) for PCR amplification. The PCR reaction system consisted of: 19 μl ddH2O, 25 μl 2×PhantaMax Buffer, 1 μl dNTP Mix, 2 μl each of upstream and downstream primers, 1 μl DNA polymerase, and 1 μl template cDNA. The amplification program was as follows: 95℃ pre-denaturation for 3 min; 95℃ denaturation for 15 s, 58℃ annealing for 15 s, 72℃ extension for 90 s, for a total of 35 cycles; and a final extension at 72℃ for 5 min. After separation by agarose gel electrophoresis, the target fragment was recovered by gel excision. The recovered fragment was ligated into the pET-28a vector, which had been double-digested with Nco I and Xho I, using homologous recombination to obtain the recombinant plasmid pET-28a-SSRK1. ECD The recombinant plasmid was transformed into E. coli JM109 competent cells and plated on LB agar plates containing 50 μg / mL kanamycin, then incubated at 37°C for 16 h. Positive clones were picked, and the plasmid was extracted and sequenced. The sequencing results were consistent with SEQ ID NO:1, indicating that the vector construction was correct.

[0042] The correctly sequenced recombinant expression strain was transformed overnight. 3 mL of the overnight culture was added to 600 mL LB liquid medium containing 50 μg / mL kanamycin and incubated at 37°C with shaking at 200 rpm for 2–3 h until the final OD reached 0.5–0.7. IPTG (final concentration 1 mM) was added, and the culture was continued at 12°C with shaking at 100 rpm for 24 h to induce protein expression. The bacterial cells were collected by high-speed centrifugation, and then resuspended in PBS buffer. This process was repeated three times. After autoclaving, the cells were centrifuged at 4°C, and the supernatant was collected to obtain the expressed protein. The prokaryotic protein was purified using affinity chromatography (using an AKTA Explorer 100 protein purifier) ​​on a His-tagged protein purification column. First, the affinity chromatography column was equilibrated with washing buffer; then the sample (the protein expression solution obtained above) was injected at a flow rate of 1 mL / min until the baseline stabilized. Elution was then performed with elution buffer, and the elution peak was collected. The components of the elution peak were desalted using an ultrafiltration tube, and then the purity of the protein was detected by SDS-PAGE electrophoresis.

[0043] Then, the Monolith Protein Labeling Kit was used to label SSRK1. ECDThe protein was fluorescently labeled (RED-NHS), and compounds 5, 6, and 7 were dissolved in DMSO to prepare 10 mM stock solutions. During the experiment, the compounds were serially diluted 16 times (maximum concentration 100 μM), and the protein concentration was fixed at 200 nM. The results were then detected using a Monolith NT.115 instrument at 20% LED energy and 40% MST energy. The results are as follows: Figure 2 As shown, compound 7 has a Kd value of 5.8 μM, significantly stronger than compound 5 (Kd value of 834 μM) and compound 6 (Kd value of 35.4 μM). Combined with interaction site analysis, compound 7 was found to be able to embed more deeply into the binding pocket of SSRK1, forming a stable interaction with Tyr263. Figure 2 (D in the original text). Therefore, compound 7 was selected as a candidate inhibitor for further research.

[0044] Example 3: Compound 7 competitively binds to SSRK1 with sterols.

[0045] At a fixed concentration of SSRK1 ECD In a system containing 200 nM and saturated concentrations of compound 7 (20 μM), the natural ligand β-sitosterol was added stepwise. The results were as follows: Figure 3 As shown, after adding compound 7, SSRK1 ECD The Kd value of β-sitosterol increased significantly, from 31.4 μM to 829 μM, demonstrating that the two competitively bind to SSRK1. ECD .

[0046] Example 4: Compound 7 inhibits the production of zoospores and oospores of Phytophthora soybeanis.

[0047] Wild-type WT and ssrk1 knockout mutants of Phytophthora soybean were cultured in a basal medium containing sitosterol with or without the addition of 100 μM compound 7 until the hyphae nearly filled the plate (Pei Y, Ji P, Miao J, Gu X, Wang H, Zhao Y, Song W, Guo Z, Zhou H, Shen D, Liu J, Si J, Yan J, Ren Y, Bao Y, Yin Z, DouD. A receptor kinase senses sterol by coupling with elicitins in auxotrophicPhytophthora. Proc Natl Acad Sci US A. 2024, 121:e2408186121.). Sporangium formation was induced (washed 4 times with sterile water, hydroponically cultured at 25℃ for 4-6 h), followed by cold shock at 4℃ for 30 min to release zoospores. Quantitative analysis was performed using a hemocytometer. Results are as follows: Figure 4 As shown, 100 μM compound 7 significantly inhibited zoospore production in wild-type (WT) *Phytophthora soybeani*, while its inhibitory activity against the ssrk1 mutant was significantly reduced. Oospore formation experiments were conducted with extended culture time to 30 days, and the number of mature oospores was counted using microscopic imaging. The results are shown below. Figure 4 As shown, similar to the results of the zoospore experiment, 100 μM compound 7 significantly inhibited the production of oospores from wild-type (WT) Phytophthora soybeanis, while its inhibitory activity against the ssrk1 mutant was significantly reduced, indicating that its antibacterial effect is highly dependent on the SSRK1 target. These results suggest that treatment with compound 7 effectively disrupts the pathogen's infection cycle and overwintering pathway.

[0048] Example 5: In vitro protective effect of compound 7 against blight of soybean, potato, and pepper.

[0049] Soybean hypocotyls grown for approximately 4 days were treated with compound 7 (final concentration 100 μM) and then inoculated with zoospores of Phytophthora soybeanis. Disease incidence was observed and photographed after 48 hours. Ten plants were treated per cycle, with three replicates. (See also...) Figure 5 In the study, compound 7 treatment significantly reduced the diseased length of soybeans by over 80%. Correspondingly, 2-3 week old peppers or approximately 6-week old potatoes were sprayed with diluted compound 7 (final concentration 100 μM), incubated in a 25℃ incubator in the dark for 12 h, and then sprayed with zoospore suspensions of *Phytophthora soybeani*, *Phytophthora capsici*, and *Phytophthora causalis*, respectively. After spraying, the plants were kept moist and grown in the dark until disease appeared. Disease development was observed, photographed, and recorded. Each treatment consisted of 15 plants, repeated 3 times. A control group was sprayed with the solvent and cultured in the same manner under the same conditions, with 15 plants treated each time, repeated 3 times. See [link to study]. Figure 5In the BC and compound 7 treatments, the diseased area of ​​potato and pepper leaves was significantly lower than that of the solvent control. These results fully demonstrate that compound 7, as a novel SSRK1-targeting inhibitor, has great potential to be developed into a highly efficient, broad-spectrum, and environmentally friendly agricultural fungicide.

[0050] Given that the inventors have discovered an inhibitor compound 7 targeting the Phytophthora sterol-sensing receptor SSRK1 and its role in the prevention and control of crop diseases, those skilled in the art, based on their knowledge of this application, can reasonably deduce that compound 7 of the present invention can be combined with pesticide excipients to prepare pesticide formulations, such as pesticide liquid formulations for spraying.

[0051] Given that the inventors have discovered an inhibitor compound 7 targeting the Phytophthora sterol-sensing receptor SSRK1 and its role in the control of crop diseases, those skilled in the art, based on their knowledge of this application, can reasonably deduce that compound 7 of the present invention can be combined with conventional crop disease control drug components to form new pesticide compositions. For example, compound 7 can be combined with fluthiazopyrone, metalaxyl, or fludioxonil.

[0052] It should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for the sake of clarity. Those skilled in the art should regard the specification as an organization, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0053] The detailed descriptions listed above are merely specific descriptions of feasible implementations of the present invention, and are not intended to limit the scope of protection of the present invention. All equivalent implementations or modifications made without departing from the technical spirit of the present invention should be included within the scope of protection of the present invention.

[0054] sequence list

[0055] SEQ ID NO:1 (Phytophthora sojae)

[0056] atgGCCGAGTGCACGGCACTCACGGAGAACGTGCTGACCTCGTCTGGCTGCCCCTCGGACTGCGACTCGTACCCGTGCGTGCTGTACTCGCCGTCGCAGGAGTCGTGCGTCGAGATGGGCGCCAGCGGCCCGTGCTACAGCGACAGCAGCTTCACGCTGCCCGGCACCAGCACCGAGTGCAACGTCACCTACCAGTGCCTGGACTCGCTGCTCTGGGACGGCGGCCAGTGGCTGCTGGCGCTGGACGCCAACAAGGAGGCCAACACCAAGACGATGGCCTACGTGACGGAGATCACCGAGCTCACGTACAGCACCTCGACGCTCTCAGTTCAACTGCAGGGCTCGCCCAGCGAATCCATCGACAAGAGCACCATCAAGGACATCTCGCTGGACCAGACCTTCTTCGACACGCCCTCGACCGCCACGAGCATGTTTCTGATCAGCATCAACCTCCGCAACACCATCAGCTCCGTGTCCATGGCCACCAATTACCAGACGCTCTACGTGACCAACGGCAACCTGAACGAGGTGCCGGACCAGTTCGCCAACTTCACGGCGCTCACCAAGCTGGACCTATCCATGAACTACATCACGGACCTGCCGGACAACTCGAGCGACGTCTGGACGGGCCTCAGCACGGTCACGGACCTCAACTTGGCCGCCAACTCGCTCACGGACTTCCCCGTCGTGCTGGACAACTTGCAGACGCTCAACCTCAGCGGCAACGCGTACACGACCATCCCGGACAACATCTACATCATGGCCGAGTCGGGCGCGCTCAAGTACCTGTACATGACTGACTGCAACCTGACCAACCTGCAGGTGTCGGACTCGCAGCTGTCGCTGCTGCAGAACCTGGCGGGCTTTGATGCGACCGTGACGATCTCAGACTGTGGCTCCGGATACGCGGCCACGACGCTGAGCAACGCGAACGTGGAGGTCTGCGCGGTGTCGACGTCCTCGTCCAGCGACGGCGGCGGCAGCAGCCAC

[0057] SEQ ID NO:2(Phytophthora sojae)

[0058] AECTALTENVLTSSGCPSDCDSYPCVLYSPSQESCVEMGASGPCYSDSSFTLPGTSTECNVTYQCLDSLLWDGGQWLLALDANKEANTKTMAYVTEITELTYSTSTLSVQLQGSPSESIDKSTIKDISLDQTFFDTPSTATSMFLISINLRNTISSVSMATNYQTLYVTNGNLNEVPDQFANFTALTKLDLSMNYITDLPDNSSDVWTGLSTVTDLNLAANSLTDFPVVLDNLQTLNLSGNAYTTIPDNIYIMAESGALKYLYMTDCNLTNLQVSDSQLSLLQNLAGFDATVTISDCGSGYAATTLSNANVEVCAVSTSSSSDGGGSSH

[0059] SEQ ID NO:3

[0060] taagaaggagatataccatgATGGCCGAGTGCACGGCACTCAC

[0061] SEQ ID NO:4

[0062] gtggtggtggtggtgctcgagGTGGCTGCTGCCGCCGCCGT。

Claims

1. The application of small molecule inhibitors targeting the Phytophthora sterol receptor SSRK1, as shown in formula (Ⅰ), in the following (a) or (c): (a) Application in inhibiting the growth and development of Phytophthora; (c) Application in the prevention and control of plant diseases caused by Phytophthora; The Phytophthora is one or more of Phytophthora soybeani, Phytophthora pathogenica, and Phytophthora capsicum; the plant is any one of soybean, potato, and chili pepper. （Ⅰ）。 2. Application of small molecule inhibitors targeting the Phytophthora sterol receptor SSRK1, as shown in formula (Ⅰ), in the following (b) or (d): (b) Use in the preparation of products for inhibiting the growth and development of Phytophthora; (d) Use in the preparation of products for the prevention and control of plant diseases caused by Phytophthora; The Phytophthora is one or more of Phytophthora soybeani, Phytophthora pathogenica, and Phytophthora capsicum; the plant is any one of soybean, potato, and chili pepper. （Ⅰ）。 3. The application according to claim 1 or 2, characterized in that, The small molecule inhibitor described herein is applied exogenously to target plants to prevent and control plant diseases caused by Phytophthora.

4. A method for inhibiting the growth and development of Phytophthora, characterized in that, The application includes applying an effective amount of the small molecule inhibitor described in claim 1 or 2 to Phytophthora or its growth environment, wherein the Phytophthora is at least one of Phytophthora soybeani, Phytophthora pathogenica, and Phytophthora capsici.

5. A method for controlling Phytophthora blight, characterized in that, The application includes the application of an effective amount of the small molecule inhibitor described in claim 1 or 2 to the target plant or the target plant's growth environment; the Phytophthora blight is at least one of soybean root rot caused by Phytophthora soybeanis, potato late blight caused by Phytophthora pathogenica, and pepper blight caused by Phytophthora capsulatum.

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