Application of coumarin-3-carboxylic acid in preventing and controlling plant bacterial diseases

Abstract

The present invention discloses the application of coumarin-3-carboxylic acid in preventing and treating plant bacterial diseases. The coumarin-3-carboxylic acid provided by the present invention has a significant inhibitory effect on plant bacterial diseases. The plant bacterial diseases are oryzae bacterial leaf blight, oryzae bacterial leaf streak, citrus canker, cantaloupe bacterial fruit spot, tomato bacterial wilt, strawberry bacterial angular leaf spot, cabbage black rot, cabbage soft rot, potato soft rot, mango bacterial angular leaf spot, cassava bacterial wilt, cucumber bacterial angular leaf spot, kiwifruit canker and banana bacterial soft rot. The coumarin-3-carboxylic acid provided by the present invention has protective and therapeutic effects on melon bacterial fruit spot.

Description

Technical Field

[0001] The present invention relates to the field of plant bacterial disease prevention and treatment, and in particular to application of coumarin-3-carboxylic acid in the prevention and treatment of plant bacterial diseases. Background Art

[0002] Coumarin-3-carboxylic acid, also known as benzopyronecarboxylic acid and 2-oxo-2H-1-benzopyran-3-carboxylic acid, belongs to the coumarin class of compounds. With a molecular formula of C₁₀H₁₀O₄ and a relative molecular mass of 190.15, it is a coumarin derivative that has attracted considerable attention for its diverse biological activities, including anti-tumor activity, lactate transport inhibition, and GPR35 agonism. In recent years, with the continuous in-depth study of the structure of this compound, it was found that after modifying the different properties of groups at different positions of the compound, a potent GPR35 agonist (6-bromo-8-nitro-7-hydroxy-3-tetrazolium coumarin) with good drug development prospects can be obtained, which has excellent drug development prospects and development value (Wei L, Wang JX, Zhang XL, Wang P, Zhao YP, Li JQ, Hou T, Qu LL, Shi LY, Liang XM, Fang Y. Discovery of 2H-chromen-2-one derivatives as G Protein-Coupled Receptor-35 agonists. Journal of Medicinal Chemistry, 2017, 60:362-372.). Moreover, when a pyrazoleamide-type pharmacological fragment is introduced into its carboxylic acid position, it can exhibit excellent inhibitory activity against a variety of medical bacteria (Liu H, Ren ZL, Gong JX, Chu MJ, Ma QW, Wang JC, LvXH. Novel coumarin-pyrazole carboxamide derivatives as potential topoisomeraseⅡinhibitors: Design, synthesis, and antibacterial activity. European Journal of Medicinal Chemistry, 2018, 157: 81-87).

[0003] A search revealed that there are currently no reports on the agricultural activity of coumarin-3-carboxylic acid at home or abroad, nor are there any reports on the inhibitory effect of coumarin-3-carboxylic acid on plant pathogenic bacteria. Summary of the Invention

[0004] In view of this, the present invention proposes the use of coumarin-3-carboxylic acid in preventing and controlling plant bacterial diseases to solve the above problems.

[0005] The technical solution of the present invention is achieved as follows:

[0006] Application of coumarin-3-carboxylic acid in preventing and controlling bacterial diseases of plants.

[0007] Furthermore, the active ingredient is coumarin-3-carboxylic acid, optionally supplemented with an auxiliary agent.

[0008] Furthermore, the concentration of coumarin-3-carboxylic acid is 150-550 mg / L.

[0009] Furthermore, the coumarin-3-carboxylic acid can be prepared into a suspension, aqueous emulsion, microemulsion, emulsifiable concentrate, wettable powder, water dispersible granules or ultra-low volume liquid.

[0010] Furthermore, the plant bacterial diseases are rice bacterial leaf blight, rice bacterial leaf streak pathogen, citrus canker, melon bacterial fruit spot pathogen, tomato bacterial wilt pathogen, strawberry bacterial angular leaf spot pathogen, cabbage black rot pathogen, cabbage soft rot pathogen, potato soft rot pathogen, mango bacterial angular leaf spot pathogen, cassava bacterial wilt pathogen, cucumber bacterial angular leaf spot pathogen, kiwifruit canker pathogen and banana bacterial soft rot pathogen.

[0011] Furthermore, the coumarin-3-carboxylic acid has an antibacterial effect on plant bacterial diseases.

[0012] Furthermore, the coumarin-3-carboxylic acid has a protective and therapeutic effect on melon bacterial fruit spot at a concentration of 50-250 mg / L.

[0013] Furthermore, coumarin-3-carboxylic acid can be chemically synthesized to obtain a white powder with a CAS number of 531-81-7, a molecular formula of C10H6O4, and a molecular weight of 190.15.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The coumarin-3-carboxylic acid provided by the present invention has a good antibacterial effect on rice bacterial blight, melon bacterial fruit spot, citrus canker, tomato bacterial wilt, and mango bacterial black spot at a test concentration of 500 mg / L, with inhibition rates all exceeding 90%. It also has a certain antibacterial effect on cabbage soft rot, with an inhibition rate of 77.16%.

[0016] Coumarin-3-carboxylic acid, at a test concentration of 100 μg / mL, exhibited excellent antibacterial effects against bacterial angular leaf spot of mango, bacterial leaf blight of rice, bacterial fruit spot of melon, bacterial wilt of tomato and soft rot of banana, with inhibition rates of 88.45%, 84.39%, 90.45%, 83.76% and 82.38%, respectively. It also exhibited a certain antibacterial effect against bacterial angular leaf spot of strawberry and bacterial angular leaf spot of cucumber, with inhibition rates of 70.55% and 73.02%, respectively.

[0017] The results of the potted test showed that coumarin-3-carboxylic acid has a strong protective effect against bacterial fruit spot of melon. When the test concentration was 200 mg / L, its protective effect was 61.88%, which was significantly better than the control agent thiophanate-methyl. It also has a strong therapeutic effect on bacterial fruit spot of melon. When the test concentration was 200 mg / L, its therapeutic effect was 53.19%, which was significantly better than the control agent thiophanate-methyl.

[0018] In summary, the compounds provided by the present invention have a significant inhibitory effect on plant pathogenic bacteria, providing a natural source of fungicidal active substances for the prevention and control of agricultural diseases; the compounds can be used to prevent and control a variety of important agricultural diseases such as rice bacterial blight, mango bacterial black spot and melon bacterial fruit spot; when used as fungicides, their high efficiency, low toxicity and safety meet the current requirements for the creation of new pesticides. DETAILED DESCRIPTION

[0019] In order to better understand the technical content of the present invention, specific examples are provided below to further illustrate the present invention.

[0020] 1. Application of coumarin-3-carboxylic acid in preventing and controlling plant diseases

[0021] While screening coumarin compounds for agricultural bactericidal applications, the inventors discovered that coumarin-3-carboxylic acid has excellent antibacterial activity against plant pathogens. The following experiment was used as an example to verify the effectiveness of coumarin-3-carboxylic acid in preventing and controlling plant bacterial diseases.

[0022] 1. Source of Coumarin-3-carboxylic acid

[0023] Coumarin-3-carboxylic acid, CAS No. 531-81-7, purity greater than 97%, was purchased from Shanghai Bid Pharmaceutical Technology Co., Ltd.

[0024] 2. Determination of the inhibitory activity of coumarin-3-carboxylic acid against plant pathogenic bacteria

[0025] 1. Test strains

[0026] Bacterial angular leaf spot of mango, Xanthomonas campestris pv.mangiferaeindicae; citrus canker, X.axonopodis pv.citri; rice bacterial leaf blight, X.oryzae pv.oryzae; rice bacterial leaf streak, X.oryzae pv.oryzicola; strawberry bacterial leaf spot, X.fragariae; cabbage black rot, X.campestris pv.campestris; cassava bacterial wilt, X.axonopodis pv.manihotis; cucumber bacterial leaf spot, Pseudomonas syringae pv.lachrymans; kiwifruit canker, P.syringaepv.actinidae; melon bacterial fruit spot, Acidovorax citrulli; tomato bacterial wilt, Ralstoniasolanacearum; potato soft rot, Pectobacterium carotovorum subsp.brasiliense, cabbage soft rot fungus P.carotovorum subsp.carotovorum, banana bacterial soft rot fungus Dickeya zeae.

[0027] 2. Test methods

[0028] 2.1 In vitro activity assay

[0029] The present invention uses a 96-well plate method to evaluate the antibacterial activity of the compound of the present invention against plant pathogenic bacteria. The 96-well plate method used to determine the inhibitory activity of coumarin-3-carboxylic acid against the above-mentioned plant pathogenic bacteria is based on the method of Shi Chao (Shi Chao et al. Inhibitory effect and mechanism of protocatechualdehyde on Cronobacter sakazakii [J]. Modern Food Science and Technology, 2017, 33(07): 105-111, 62.). The prepared bacterial suspension is added to a 96-well ELISA plate, 10 μL per well. The sample control group is added with 10 μL of bacterial suspension and 200 μL of liquid culture medium, the blank control group is added with 200 μL of liquid culture medium, and a compound solution control is set at 200 μL per well. Mix the drug solution and bacterial suspension by pipetting. Place the sample in an incubator with shaking (500 rpm) at 28-30°C for 18-24 hours. Measure the absorbance of the bacterial suspension using a microplate reader. Calculate the inhibitory effect of the compound on the bacteria using the following formula.

[0030] Bacterial inhibition rate (%) = {(control group OD 600 —Blank control group OD 600)-(OD600 of test group-OD600 of compound solution control) / (OD600 of control group-OD600 of blank control group) X 100%

[0031] 2.2 Data Analysis

[0032] The antibacterial activity of coumarin-3-carboxylic acid against 14 plant pathogens was tested indoors, and the results are shown in Table 1. At a test concentration of 100 μg / mL, coumarin-3-carboxylic acid exhibited excellent antibacterial activity against Pathogenes spp. of mango, Xanthoceras oryzae, Bacterial fruit spot of melon, Bacterial wilt of tomato, and Pathogenes spp. of banana, with inhibition rates of 88.45%, 84.39%, 90.45%, 83.76%, and 82.38%, respectively. It also exhibited some antibacterial activity against Pathogenes spp. of strawberry and Pathogenes spp. of cucumber, with inhibition rates of 70.55% and 73.02%, respectively. However, its antibacterial activity against Pathogenes spp. of cabbage was poor, with an inhibition rate of only 30.23%.

[0033] Table 1 Antibacterial activity of coumarin-3-carboxylic acid against 8 plant pathogenic bacteria

[0034]

[0035]

[0036] 2.2 Pot test method

[0037] The live pot test of coumarin-3-carboxylic acid against melon bacterial fruit spot was slightly improved by the reference method: the five treatments of concentration 1, concentration 2, concentration 3, 20% thiophanate-methyl suspension 100 mg / L and clean water were evenly sprayed on melon (variety: Yangjiaomi) seedlings, and then each pot was sprayed with a suspension of fruit spot pathogen (concentration 1×10 9 CFU / mL), each treatment was replicated three times, with six seedlings per replicate, one plant per pot. The seedlings were cultured under moisturizing and light conditions. Disease development was observed on the 7th and 14th days of culture, and the disease index (Formula 1) and control efficacy (Formula 2) were calculated [Reference: Identification of Bacillus sp. BJ_6 and Control of Bacterial Fruit Spot of Melon - Jia Huihui]. Leaf disease grade was graded [Refer to "Efficacy II" "Control of Bacterial Angular Leaf Spot of Cucumber with Fungicides"]:

[0038] Level 0: no lesions;

[0039] Level 1: The lesion area accounts for less than 5% of the entire leaf area;

[0040] Level 3: The lesion area accounts for 6-10% of the entire leaf area;

[0041] Level 5: The lesion area accounts for 11-20% of the entire leaf area;

[0042] Level 7: The lesion area accounts for 21-50% of the entire leaf area;

[0043] Level 9: The lesion area accounts for more than 51% of the entire leaf area;

[0044] Calculation formula for drug efficacy:

[0045] Disease index = ∑(number of diseased leaves at each level × relative disease level) / (total number of leaves surveyed × highest disease level) × 100(1)

[0046] Control effect (%) = (control disease index - treatment disease index) / control disease index × 100 (2)

[0047] Potted plant test results (Table 2) show that coumarin-3-carboxylic acid exhibits strong protective and therapeutic effects against bacterial fruit spot on melons, with the protective effect outperforming the therapeutic effect. At a test concentration of 200 mg / L, its protective effect reached 61.88%, significantly superior to the control agent, thiophanate-methyl. It also exhibited a strong therapeutic effect against bacterial fruit spot on melons, achieving a therapeutic effect of 53.19% at a test concentration of 200 mg / L, significantly superior to the control agent, thiophanate-methyl.

[0048] Table 2 Protective and therapeutic effects of coumarin-3-carboxylic acid on melon bacterial fruit spot

[0049]

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. Application of coumarin-3-carboxylic acid in the prevention and control of plant bacterial diseases; The plant bacterial diseases are bacterial leaf blight of rice, bacterial leaf streak of rice, citrus canker, melon bacterial fruit spot, tomato bacterial wilt, strawberry bacterial angular leaf spot, cabbage black rot, cabbage soft rot, potato soft rot, mango bacterial angular leaf spot, cassava bacterial wilt, cucumber bacterial angular leaf spot, kiwifruit canker and banana bacterial soft rot. The coumarin-3-carboxylic acid concentration is 50-550 mg / L.

2. The use according to claim 1, characterized in that The coumarin-3-carboxylic acid is the active ingredient.

3. The use according to claim 1, characterized in that The coumarin-3-carboxylic acid can be prepared into a suspension, an aqueous emulsion, a microemulsion, an emulsifiable concentrate, a wettable powder, a water-dispersible granule or an ultra-low volume liquid.

4. The use according to claim 1, wherein The coumarin-3-carboxylic acid has an antibacterial effect on plant bacterial diseases.

5. The use according to claim 1, characterized in that The coumarin-3-carboxylic acid has protective and therapeutic effects on melon bacterial fruit spot.

6. The use according to claim 5, characterized in that The coumarin-3-carboxylic acid concentration is 50-250 mg / L.

Images