Application of Microminutin or salt thereof in prevention and treatment of plant pathogenic fungi

Abstract

The invention provides an application of a coumarin compound Microminutin or a salt thereof in prevention and treatment of plant pathogenic fungi, and belongs to the technical field of bactericides. The coumarin compound Microminutin or the salt thereof provided by the invention is used as a bacteriostatic active component and has a structure as shown in a formula I in the specification. The coumarin compound Microminutin is separated from branches and leaves of Murraya paniculata belonging to rutaceae, has broad-spectrum antibacterial activity on various plant pathogenic bacteria diseases, can be used for preventing and treating various plant diseases independently or compounded with other medicaments, and can also be used for fresh keeping of fruits and vegetables.

Description

Technical Field

[0001] The invention belongs to the technical field of agricultural fungicides, and particularly relates to application of Microminutinin or its salt in preventing and controlling plant pathogenic fungi. Background Art

[0002] Plant diseases are an important factor affecting agricultural production. In order to prevent the occurrence and development of plant diseases and reduce agricultural losses, a large number of chemical fungicides are applied. However, due to the long-term cumulative use of chemical fungicides, problems such as drug resistance have been caused. Therefore, the development of new green fungicides from plant-derived active molecules has become the focus of pesticide companies and researchers.

[0003] The compound Microminutinin is a known coumarin compound. It has been reported that the compound exists in Micromelum minutum, Micromelum falcatum of the Rutaceae family and Leea thorelii Gagnep of the Vitaceae family. In addition, Wei-Lun Huang et al. have conducted a total synthesis of Microminutinin. However, there has been no report on the biological activity of Microminutinin so far. Summary of the invention

[0004] The object of the present invention is to provide a use of a coumarin compound Microminutinin or a salt thereof in preventing and controlling plant pathogenic fungi. The coumarin compound Microminutinin or a salt thereof, as an antibacterial active ingredient, has a broad-spectrum antibacterial activity against a variety of plant pathogenic fungal diseases.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention provides the use of a coumarin compound Microminutinin or a salt thereof in preventing and controlling plant pathogenic fungi. The coumarin compound Microminutinin or a salt thereof is used as an antibacterial active ingredient and has a structure shown in Formula I:

[0007]

[0008] Preferably, the plant pathogenic fungi include one or more of ring rot pathogens, ring spot pathogens, anthracnose pathogens, fruit rot pathogens, brown star disease pathogens, corruption pathogens, root rot pathogens, wilt pathogens, gray mold pathogens, downy mildew pathogens, and blight pathogens.

[0009] Preferably, the preparation method of the coumarin compound Microminutinin comprises isolating the coumarin compound Microminutinin from any one plant of the genera Murraya, Osmanthus and Pyrocyrrhiza.

[0010] The invention also provides a bactericide, comprising a solvent and the coumarin compound Microminutinin or a salt thereof.

[0011] The present invention also provides a fungicide composition, which comprises a fungicide I and other effective active ingredients; the fungicide I comprises the coumarin compound Microminutinin or its salt; and the other effective active ingredients comprise one or more of a fungicide II, an insecticide, a herbicide and a plant growth regulator.

[0012] Preferably, the fungicide II includes one or more of amides, dicarboximides, methoxyacrylates, triazoles, imidazoles, oxazoles, thiazoles, morpholines, pyrroles, pyridines, pyrimidines, quinolines, carbamates, organophosphorus, and antibiotics.

[0013] The present invention also provides a fungicide synergist, which comprises a synergistic component and an adjuvant, wherein the synergistic component comprises the coumarin compound Microminutinin or a salt thereof.

[0014] The present invention also provides a fruit and vegetable preservative, which comprises other preservative ingredients, adjuvants and the coumarin compound Microminutinin or its salt.

[0015] The present invention also provides a medicinal fertilizer, which comprises a bactericidal drug component and a fertilizer component, wherein the bactericidal drug component comprises the coumarin compound Microminutinin or a salt thereof.

[0016] The present invention also provides a method for preventing and controlling plant diseases, which uses the coumarin compound Microminutinin or its salt to prevent and control plant diseases.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention provides the use of a coumarin compound Microminutinin or a salt thereof in preventing and controlling plant pathogenic fungi. The coumarin compound Microminutinin or a salt thereof is used as an antibacterial active ingredient, has a broad-spectrum antibacterial activity against a variety of plant pathogenic fungal diseases, can be used alone or in combination with other agents for the prevention and control of a variety of plant fungal diseases, and provides a new means for preventing and controlling plant fungal diseases. At the same time, the compound can also be used for fruit and vegetable preservation, bactericidal synergist and medicinal fertilizer. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is the coumarin compound Microminutinin in Example 1 1 H NMR spectrum.

[0020] Figure 2 is the compound 1 in Example 1 13 C NMR spectrum. DETAILED DESCRIPTION

[0021] The present invention provides the use of a coumarin compound Microminutinin or a salt thereof in preventing and controlling plant pathogenic fungi. The coumarin compound Microminutinin or a salt thereof is used as an antibacterial active ingredient and has a structure shown in Formula I:

[0022]

[0023] In the present invention, Microminutinin, as shown in the chemical structure (I), can be isolated from plants of the genera Murraya, Euchrestifolia and Pyrocyrthospermum. As an embodiment, the coumarin compound Microminutini is isolated from the branches and leaves of Murraya euchrestifolia Hayata of the Rutaceae family. As an embodiment, the plant pathogenic fungi include one or more of the pathogens of ring rot, ring spot, anthracnose, fruit rot, brown star, putrefaction, root rot, wilt, gray mold, downy mildew and blight. As an embodiment, the plant pathogenic fungi also include one or more of rice blast, peanut crown rot, melon leaf spot, tea red leaf spot, pepper white spot, wax gourd leaf spot, sesame leaf spot, watermelon spot, tomato leaf mold and eggplant leaf mold. Preferably, the ring spot pathogens include one or more of pear ring spot pathogens, apple ring spot pathogens, soybean ring spot pathogens, sesame ring spot pathogens, and kidney bean ring spot pathogens; the wheel spot pathogens include tea ring spot pathogens, strawberry ring spot pathogens, kiwi fruit ring spot pathogens, lentil ring spot pathogens, water spinach ring spot pathogens, citrus ring spot pathogens, pepper ring spot pathogens, grape ring spot pathogens, lettuce ring spot pathogens, lettuce ring spot pathogens, watermelon ring spot pathogens, taro ring spot pathogens, mung bean ring spot pathogens, cherry ring spot pathogens, One or more of the anthracnose pathogens, the anthracnose pathogens including citrus anthracnose, grape anthracnose, cucumber anthracnose, watermelon anthracnose, melon anthracnose, pepper anthracnose, cowpea anthracnose, tomato anthracnose, strawberry anthracnose, apple anthracnose, pear anthracnose, peach anthracnose, potato anthracnose, lettuce anthracnose, corn anthracnose, oil tea anthracnose, tobacco anthracnose, broad bean anthracnose, banana anthracnose, walnut anthracnose anthracnose, rape anthracnose, water spinach anthracnose, pumpkin anthracnose, chestnut anthracnose, spinach anthracnose, mulberry anthracnose, persimmon anthracnose, papaya anthracnose, peanut anthracnose, mung bean anthracnose, lemon anthracnose, cabbage anthracnose, hawthorn anthracnose, the fruit rot pathogens include apple fruit rot, peach fruit rot, peanut fruit rot, strawberry fruit rot, eggplant fruit rot, pomegranate fruit rot, orange fruit rot, One or more of pumpkin fruit rot pathogens, melon fruit rot pathogens, longan fruit rot pathogens, cantaloupe fruit rot pathogens, tomato fruit rot pathogens, watermelon fruit rot pathogens, pitaya fruit rot pathogens, zucchini fruit rot pathogens, citrus fruit rot pathogens, cherry fruit rot pathogens, wax apple fruit rot pathogens, pepper fruit rot pathogens, and kiwi fruit rot pathogens; the brown star disease pathogens include one or more of tobacco brown star disease pathogens, eggplant brown star disease pathogens, pear brown star disease pathogens, apple brown star disease pathogens, tea brown star disease pathogens, and hawthorn brown star disease pathogens;The rot pathogens include one or more of lotus root rot pathogens, lettuce rot pathogens, romaine lettuce rot pathogens, watermelon rot pathogens, potato rot pathogens, taro rot pathogens, water spinach rot pathogens, tomato rot pathogens, zucchini rot pathogens, and rice sheath rot pathogens; the root rot pathogens include peanut root rot pathogens, strawberry root rot pathogens, eggplant root rot pathogens, cucumber root rot pathogens, sweet potato root rot pathogens, onion root rot pathogens, tomato fruit rot pathogens, beet root rot pathogens, jujube root rot pathogens, silkworm root rot pathogens, etc. The wilt pathogens include one or more of bean fruit rot pathogens, sweet potato root rot pathogens, pea root rot pathogens, cowpea root rot pathogens, corn root rot pathogens, tobacco root rot pathogens, pepper root rot pathogens, pumpkin root rot pathogens, ginseng root rot pathogens, pepper root rot pathogens, wolfberry root rot pathogens, and taro root rot pathogens; the wilt pathogens include cucumber wilt pathogens, cotton wilt pathogens, tomato wilt pathogens, melon wilt pathogens, watermelon wilt pathogens, wax gourd wilt pathogens, broad bean wilt pathogens, cowpea wilt pathogens, pepper wilt pathogens, eggplant wilt pathogens The pathogens of gray mold include one or more of gray mold of grape, gray mold of cucumber, gray mold of tomato, gray mold of strawberry, gray mold of pepper, gray mold of eggplant, gray mold of leek, gray mold of kiwi and gray mold of spinach; the pathogens of downy mildew include one or more of downy mildew of watermelon, downy mildew of cucumber and downy mildew of wax gourd. , one or more of downy mildew of cabbage, pepper, grape, tobacco, lettuce, spinach, rose, soybean, beet, pea, loofah, and green onion; the blight pathogens include one or more of watermelon blight, cucumber blight, wax gourd blight, melon blight, pepper, potato, tomato, and taro. More preferably, the plant pathogenic fungi include one or more of tea ring spot, pear ring rot, citrus anthracnose, tobacco brown spot, lotus rot, and kiwi fruit rot. ,

[0024] In the present invention, the coumarin compound Microminutinin or its salt is used as an antibacterial active ingredient, and has a broad-spectrum antibacterial activity against a variety of plant pathogenic fungal diseases, especially better prevention effect against tea ring spot, pear ring spot, citrus anthracnose, tobacco brown spot, lotus rot and kiwi fruit rot. The coumarin compound Microminutinin or its salt still has a control effect on tea ring spot pathogen, pear ring spot pathogen, citrus anthracnose pathogen, tobacco brown spot pathogen, lotus rot pathogen and kiwi fruit rot pathogen at a lower dosage. The lower dosage is 10 μg / mL.

[0025] In the present invention, since the coumarin compound Microminutinin or its salt has a wide range of antibacterial effects, the coumarin compound Microminutinin or its salt can be used to protect important crops and livestock in agriculture and horticulture, as well as environments frequented by humans from harm by pathogens; it can also be used to preserve fruits and vegetables.

[0026] The present invention also provides a fungicide, comprising a solvent and the coumarin compound Microminutinin or a salt thereof. Preferably, the solvent is an organic solvent; more preferably, the organic solvent includes one of acetone, dichloromethane and chloroform; and the organic solvent is acetone.

[0027] The coumarin compound Microminutinin or its salt in the fungicide of the present invention is dissolved or dispersed in a medium as an active ingredient and adsorbed on a carrier or formulated into a preparation so that it is easier to disperse when used as a fungicide. As an implementable embodiment, the fungicide is preferably prepared into a concentrated emulsion, powder, emulsifiable concentrate, aqueous emulsion, paste, disintegrant, fumigant, bait, gel, granule, capsule, seed coating, suspension, tablet, water-soluble liquid, water dispersant, dry suspension and wettable powder.

[0028] The present invention also provides a fungicide composition, which includes fungicide I and other effective active ingredients; the fungicide I includes the coumarin compound Microminutinin or its salt; the other effective active ingredients include one or more of fungicide II, insecticide, herbicide and plant growth regulator. The fungicide composition of the present invention means that Microminutinin or its salt can be used together with any one or more of fungicide, insecticide, herbicide and plant growth regulator.In the present invention, the fungicide II preferably includes one or more of amides, dicarboximides, methoxyacrylates, triazoles, imidazoles, oxazoles, thiazoles, morpholines, pyrroles, pyridines, pyrimidines, quinolines, carbamates, organophosphorus, and antibiotics; more preferably, the amides include flumorph, oxazolidinone, high-efficiency metalaxyl, high-efficiency bensulfuron, dichlorocyanamide, sulfaquinoxaline, metalaxyl, thiocyanamide, thiocyanamide, thiocyanamide, thiocyanamide, chloranil, cyproconazole, cyprodinil, cyprodinil, cyprodinil, cyprodinil, cyanamide, cyprodinil, cyprodinil, pyraclostrobin, penthiopyrad, dimethomorph, oxazolidinone, oxazolidinone, chloranil, cyprodin ... One or more, the dicarboximide includes one or more of ethoxystrobin, isoproconazole, and procymidone, the methoxyacrylate includes one or more of azoxystrobin, myclobutanil, fluoxastrobin, kresoxim-methyl, fenoxystrobin, oxazolidinone, picoxystrobin, pyraclostrobin, trifloxystrobin, fenoxstrobin, and fenoxam, the triazole includes oxepiconazole, oxaconazole, cyproconazole, difenoconazole, diniconazole, high-efficiency diniconazole, fluepiconazole, nitrobenazole, fluquinconazole, flusilazole, flutriafol, hexaconazole, imipenem, cyproconazole, metconazole, myclobutanil, penconazole, propiconazole, prothioconazole, silyfloxacin, tebuconazole, tetrafluconazole, triadimenol, triathione, bifenthrin The invention relates to one or more of alcohols, the imidazoles include one or more of thiabendazole, maisugin, imazalil, high-efficiency imazalil, prochloraz, prochloraz manganese complex, flubimazole, cyazolin, fenamidone, oxadiazole, and rice blast ester, the oxazoles include one or more of oxadiazole, pyraclostrobin, oxadiazole, and oxadiazole, the thiazoles include one or more of ethaboxam, oxadiazole, octhiazol, and benzathiacyanate, the morpholines include one or more of dodecacyclic morpholine, fenpropimorph, tridecamorph, flumorph, and dimethomorph, the pyrroles include one or more of fenpiclonil and fludioxonil, the pyridines include fluazinam, pyraclostrobin, cyclamoxadone, and cyclamoxadone. , boscalid, fluobosyl, and pyraclostrobin, the pyrimidines include one or more of cyprodinil, fluopyram, myrimidine, pyrimethanil, chlorfenapyr, and flufenapyr, the quinolines include one or more of mite killer, dicyanoanthraquinone, ethoxyquinoline, 8-hydroxyquinoline, propoxyquinoline, and phenoxyquinoline, the carbamates include one or more of ethotripsy, isopyram, benzathiapiprolin, cymoxanil, and sulfamethoxam, the organophosphorus includes one or more of dichlorvos, isothiopyrad, pyraclostrobin, and methyl tolclofos, the antibiotics include one or more of blasticidin, kasugamycin, polyoxin, and polyoxin.The fungicide II of the present invention preferably also includes validamycin, Jinggangmycin, streptomycin, metalaxyl, furazolidone, bensulfuron, furamide, oxadiazine, carbendazim, benomyl, methyl thiophanate, triadimefon, pyrimidine sulfonate, dimethoate, pyrimidine, captan, folpet, vinclozolin, fluclozolin, sclerotin, chlorothalonil, rice blast, rice blast, leaf blight, pentachloronitrobenzene, thiram, mancozeb , propineb, fosetyl-aluminum, sulfur, Bordeaux mixture, copper sulfate, copper oxychloride, cuprous chloride, copper hydroxide, activated ester, pencuron, pyridamole, fenpropidin, tetrachlorophthalide, pyroquilon, spiroxafil, tricyclazole, triazoline, cymoxanil, docodine, biguanide salt, biguanide octylamine, chloranil, benzylsulfuron, toluenesulfuron, indole ester, sodium sulfamethoxazole, quinacridone, allylthiazole, bronopol. The fungicidal composition of the present invention can be used in the form of a preparation; in the fungicidal composition, at least one liquid or solid carrier is added, and a suitable surfactant can be added when necessary.

[0029] The present invention also provides a fungicide synergist, which comprises a synergistic component and an adjuvant, wherein the synergistic component comprises the coumarin compound Microminutinin or its salt. The fungicide synergist of the present invention is used to improve the fungicide effect of other fungicides.

[0030] The present invention also provides a fruit and vegetable preservative, which comprises other preservative ingredients, adjuvants and the coumarin compound Microminutinin or its salt. The fruits and vegetables described in the present invention refer to fruits and / or vegetables, and other preservative ingredients and adjuvants are not further limited, and any ingredients and adjuvants that can sterilize and preserve with the coumarin compound Microminutinin or its salt can be used.

[0031] The present invention also provides a medicated fertilizer, which includes a fungicide component and a fertilizer component, wherein the fungicide component includes the coumarin compound Microminutinin or its salt. The present invention does not further limit the above fertilizer component and source, and the fertilizer component is prepared by a conventional method in the art or is commercially available.

[0032] The present invention also provides a method for preventing and controlling plant diseases, which uses the coumarin compound Microminutinin or its salt to prevent and control plant diseases.

[0033] The present invention has no special restrictions on the source of the coumarin compound Microminutinin or its salt, and it can be prepared by conventional methods in the art or purchased from the market.

[0034] In the following embodiments of the present invention, the test strains Botryosphaeria dothidea (Moug: Fr) Ces & De Not, Pestalotiopsis theae, Colletotrichum gloeosporioides, Alternaria altermsp, Botrytis cinerea Persoon, Alternaria alternata, Fusarium commune, Fusarium solani, Fusarium oxysporum, Botrytis cinerea Persoon, Fusarium proliferatum, and Pseudoperonospora cubensis (Berk & Cur.) Rostov. were all provided by the Pesticide Research Group of the College of Agriculture, Jiangxi Agricultural University.

[0035] Unless otherwise specified, the test methods used in the following examples are all conventional test methods; the materials and reagents used are reagents and materials that can be obtained from commercial channels unless otherwise specified.

[0036] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention.

[0037] Example 1

[0038] Isolation and identification of microminutinin

[0039] The compound Microminutinin has the structure shown in Formula I:

[0040]

[0041] 1. Separation

[0042] Selection of separation and extraction materials: branches and leaves of Murraya euchrestifolia Hayata of the genus Murraya in the Rutaceae family.

[0043] Specific steps: crush the leaves and branches of the Rutaceae family Murraya odorata (4.0 kg), add 3 times the mass of 95% methanol, and extract them under hot reflux for 3 times, the extraction temperature is 60°C, and each time for 3 hours. Filter and combine the three extracts, and concentrate under reduced pressure to an extract (0.694 kg). Use MCI gel (CHP20P, 70-150 μm) (Mitsubishi Chemical Industries Ltd., Japan) and ethanol / water (v / v 80:20-90:10) as the eluent to remove chlorophyll in the extract. Then use a reverse silica gel column (RP-18) and methanol / water (v / v 30:70; 60:40; 80:20; 90:10) gradient elution, and divide it into 4 fractions according to the gradient, namely: AD. The D segment (162 g) was mixed with 100-200 mesh silica gel, and separated by column chromatography with 200-300 mesh silica gel, and the mobile phase was petroleum ether / acetone (v / v 10:0, 10:1, 5:1, 4:1, 3:1, 2:1, 1:1, 0:10) for gradient elution. According to thin layer chromatography (TLC), 5% sulfuric acid and anhydrous ethanol were used for color development to divide into 5 fractions, namely D.1-D.5. Among them, D.2 was further chromatographed on a silica gel column (200-300 mesh) with petroleum ether / acetone (v / v 5:1, 4:1, 3:1, 2:1, 1:1, 0:1) as the eluent to obtain 6 fractions, namely D.2.1-D.2.6. D.2.2 was subjected to repeated column chromatography (200-300 mesh) with petroleum ether / acetone (v / v 4:1) as the mobile phase to obtain a fraction with a single spot detected by TLC. The fraction was further purified by HPLC (methanol / water, v / v 82:18) to obtain the compound Microminutinin (65.3 mg).

[0044] 2. Identification

[0045] The structure of the compound Microminutinin obtained above was identified by nuclear magnetic resonance and mass spectrometry.

[0046] 3. Identification results

[0047] Microminutinin 1 H NMR spectrum results are shown in Figure 1 ; The above compound Microminutinin 13 C NMR spectrum results are shown in Figure 2 .

[0048] The specific physical and chemical properties and Pop data of the compound Microminutinin are as follows:

[0049] Needle-shaped substance in methanol. ESI-MS, m / z: 243 [M+H] + ,1 H-NMR (400MHz,CDCl3):δ H :7.65(1H,d,J=9.6Hz,H-4),7.32(1H,d,J=8.3Hz,H-5),6.78(1H,d,J=8.3H z,H-6),6.55(1H,d,J=5.8Hz,H-2'),6.23(1H,d,J=9.6Hz,H-3),5.73(1H,br s,H-6'a),5.19(1H,br s,H-6'b),4.66(1H,dd,J=5.8,1.6Hz,H-3'),4.49(1H,d,J=12.4,1.6Hz,H-5'a),4.41(1H,ddd,J=12.4,1.6,1.0Hz,H-5'b); 13 C-NMR (100MHz,CDCl3):δ C :162.2(C,C-7),160.5(C,C-2),151.5(C,C-9),144.3(C,C-4'),140.0(CH,C-4),129.5(CH,C-5),113.7(CH,C-2'),1 13.6(C,C-10),113.4(C,C-8),112.6(CH,C-3),109.6(CH2,C-6'),106.9(CH,C-6),70.8(CH2,C-2'),48.6(CH,C-3').

[0050] Example 2

[0051] Determination of antibacterial activity of microminutinin in vitro

[0052] 1. Detection method

[0053] With reference to the pesticide indoor bioassay test guidelines, the antibacterial activity of the compound Microminutinin described in Example 1 against 11 plant pathogenic fungi was determined by the mycelium growth rate inhibition method, referring to the method of Fang Zhongda (Fang Zhongda. Plant Pathology Research Methods. China Agriculture Press).

[0054] Specific steps: The compound Microminutinin separated and obtained in Example 1 is completely dissolved in acetone, and then diluted to 1000 μg / mL with sterile water to prepare a mother solution. The above mother solutions are respectively taken and added to the melted PDA culture medium (about 50°C), mixed evenly and poured into a culture dish to prepare a poisonous culture medium with a concentration of 200 μg / mL of Microminutinin. The acetone culture medium mixed with the same volume is used as a blank control, and 500 times of 50% carbendazim is used as a fungicide control. Use a hole puncher to take a 6mm diameter test pathogen cake, and inoculate it in the center of the poisonous culture medium and the control culture medium respectively, with the side with hyphae facing the culture medium. Place a cake in each culture dish and place it in a constant temperature incubator at 25°C for 4 days. Each treatment is repeated three times. The colony diameter (mm) is determined by the cross method. The antibacterial rate is calculated according to the following formula.

[0055]

[0056] Table 1 Antibacterial activity of Microminutin at a concentration of 200 μg / mL against 11 pathogens

[0057] Pathogens Microminutin Pear ring rot pathogen (B. dothidea) 100％ Tea leaf spot pathogen (P.theae) 100％ Citrus Anthracnose Pathogen (C. gloeosporioides) 100％ Apple fruit rot pathogen (A.altermsp) 100％ Tobacco brown spot pathogen (A. alternata) 100％ Lotus root corruption pathogen (F. commune) 100％ Sweet potato root rot pathogen (F.solani) 100％ Watermelon wilt pathogen (F.oxysporum) 100％ Grape gray mold pathogen (B. cinerea) 100％ Taro blight pathogen (F.proliferatum) 100％ Watermelon downy mildew pathogen (P.cubensis) 100％

[0058] 2. Results

[0059] The inhibition rates of the tested bacteria at a concentration of 200 μg / mL of the compound Microminutinin are shown in Table 1. The results show that the inhibition rates of the compound Microminutinin at a concentration of 200 μg / mL on the 11 pathogens in the table are all 100%.

[0060] Example 3

[0061] Determination of the in vivo efficacy of microminutinin against diseases

[0062] 1. Detection method

[0063] The in vivo efficacy against pear ring spot and tea ring spot was determined using the plant tissue method.

[0064] The specific method is as follows:

[0065] Disease-free and undamaged pear fruits or new tea leaves were selected for the test. The test compound Microminutinin was the compound Microminutinin isolated in Example 1, and was treated at a concentration of 300 μg / mL. At the same time, a water control and a 500-fold solution of 50% carbendazim were set as fungicide controls. Three equally spaced wounds with a diameter of 6 mm and a depth of 3 mm were made on the pear fruits with a sterile perforator, and mechanical damage was uniformly made on the tea leaves with a blade over an area of ​​6 mm in diameter.

[0066] For the protective effect test, 50 μL of the above-mentioned 300 μg / mL Microminutinin solution was first added to each wound. After 24 hours, a 6 mm diameter PDA cake containing plant pathogen hyphae was embedded in the pear wound or placed close to the wound of tea leaves, with the hyphae facing inward. For the curative effect test, the wound of the pear fruit or tea leaves was inoculated with bacteria. After 24 hours, 50 μL of the above-mentioned 300 μg / mL Microminutinin solution was added to each wound. For the water control, 50 μL of water was added, and for the fungicide control, 50 μL of 50% carbendazim 500 times solution was added. Each treatment involved three replicates, and the culture was carried out for 6-7 days. The diameter of the lesion (mm) was determined by the cross method. The antibacterial rate of the lesion diameter was calculated according to the following formula.

[0067]

[0068] 2. Results

[0069] The measurement results are shown in Table 2:

[0070] Table 2 The control effect of Microminutin on pear ring rot and tea ring spot in plant tissues

[0071] Pathogens Microminutin Pear ring rot pathogen (B. dothidea) 78.5％ Tea leaf spot pathogen (P.theae) 86.7％

[0072] The results of plant tissue method showed that the inhibition rate of the compound Microminutinin at a concentration of 300 μg / mL on the lesion diameter of pear ring spot in plant tissues was 78.5%, and the inhibition rate on the lesion diameter of tea ring spot in plant tissues was 86.7%.

[0073] Example 4

[0074] Determination of in vitro antibacterial activity of microminutinin and other fungicides

[0075] 1. Detection method

[0076] The inhibitory activity of the compound Microminutinin isolated in Example 1 on plant pathogenic fungi was determined by the method of Fang Zhongda (Fang Zhongda. Plant Pathology Research Methods. China Agriculture Press). The specific steps were the same as those in Example 2.

[0077] The colony diameter (mm) was measured by the cross method. The inhibition rate was calculated according to the following formula.

[0078]

[0079] 2. Results

[0080] The inhibitory effects on 6 pathogens are shown in Table 3:

[0081] Table 3 In vitro antibacterial activity of Microminutinin combined with other fungicides against 6 pathogens (%)

[0082]

[0083] Note: M in the sample is Microminutinin, and the concentration is the concentration of Microminutinin + the concentration of the compound fungicide.

[0084] The test results of the mycelium growth rate method showed that when Microminutinin was compounded with the other 10 fungicides in a 1:1 mass ratio to a concentration of 200μg / mL, the in vitro inhibition rates against the six pathogens were all higher than 83.51%, among which the inhibition rates against tea ring spot pathogen and kiwi fruit rot pathogen were as high as 100%, which was equivalent to the inhibitory effect of Microminutinin when used alone at 200μg / mL.

[0085] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. Use of coumarin compound Microminutinin or its salt in preventing and controlling plant pathogenic fungi, characterized in that: The coumarin compound Microminutinin or its salt as an antibacterial active ingredient has a structure shown in Formula I:

2. The application according to claim 1, characterized in that: The plant pathogenic fungi include one or more of the pathogens of ring rot, ring spot, anthracnose, fruit rot, brown star, putrefaction, root rot, wilt, gray mold, downy mildew, and blight.

3. The application according to claim 1, characterized in that: The preparation method of the coumarin compound Microminutinin comprises the step of isolating the coumarin compound Microminutinin from any one plant of the genus Murraya, the genus Osmanthus and the genus Pyrola.

4. A bactericide, characterized in that: The invention comprises a solvent and the coumarin compound Microminutinin or a salt thereof as claimed in claim 1.

5. A bactericidal composition, characterized in that: The fungicide composition comprises fungicide I and other effective active ingredients; the fungicide I comprises the coumarin compound Microminutinin or its salt as described in claim 1; the other effective active ingredients comprise one or more of fungicide II, insecticides, herbicides and plant growth regulators.

6. The bactericidal composition according to claim 5, characterized in that: The bactericide II includes one or more of amides, dicarboximides, methoxyacrylates, triazoles, imidazoles, oxazoles, thiazoles, morpholines, pyrroles, pyridines, pyrimidines, quinolines, carbamates, organophosphorus, and antibiotics.

7. A bactericidal synergist, characterized in that: The bactericidal synergist comprises a synergistic component and an adjuvant, and the synergistic component comprises the coumarin compound Microminutinin or a salt thereof as claimed in claim 1.

8. A fruit and vegetable preservative, characterized in that: The fruit and vegetable preservative comprises other preservative ingredients, adjuvants and the coumarin compound Microminutinin or its salt as claimed in claim 1.

9. A medicinal fertilizer, characterized in that: The medicated fertilizer comprises a fungicide component and a fertilizer component, wherein the fungicide component comprises the coumarin compound Microminutinin or a salt thereof as claimed in claim 1.

10. A method for preventing and controlling plant diseases, characterized in that: The coumarin compound Microminutinin or its salt as claimed in claim 1 is used to prevent and control plant diseases.

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