Application of iso-cryptolepine derivative

Abstract

The invention relates to the technical field of natural medicinal chemistry, and particularly discloses an application of an iso-cryptolepine derivative in prevention and treatment of plant bacterial diseases, the structural formula of the iso-cryptolepine derivative is # imgabs0, the synthesis method of the iso-cryptolepine derivative is simple, and the raw materials are easy to obtain; the compound shows an excellent inhibition effect on bacterial diseases such as Xanthomonas oryzae pv. Oryzae and Xanthomonas citri pv. Citri, the activity of the compound is higher than that of commercially available control drugs bismerthiazol and thiediazole copper, and the compound has a great application value in the aspect of preventing and treating plant pathogenic bacteria.

Description

Technical Field

[0001] The invention relates to the technical field of natural drug chemistry, and in particular to an application of isoflavone derivatives. Background Art

[0002] Plant bacterial diseases are the most difficult to control during the growth of crops. They can cause large-scale damage to crops and cause huge economic losses. Rice bacterial blight can cause a 20%-50% reduction in rice production, and citrus canker is a serious threat to important citrus fruit crops worldwide. Due to the widespread and continuous use of chemical fungicides, plant pathogenic bacteria have become more resistant to fungicides, seriously threatening human health and environmental safety. Finding new control agents has become a top priority.

[0003] Isocryptolepine is one of the natural alkaloids with an indolequinoline structure extracted and separated from the rhizomes of the traditional African medicinal material Cyperus sanguineus by Bodo et al. in 1995. Currently, reports on the biological activities of this alkaloid and its derivatives are mainly concentrated on anti-malarial, anti-hyperglycemic, anti-tumor, anti-inflammatory and other aspects. For example, publication number CN113912603A discloses an isocryptolepine analogue, which has good growth inhibitory activity against tuberculosis strains and can be used to prepare anti-tuberculosis drugs; however, there are few reports on the use of this type of alkaloid and its derivatives in preventing and controlling agricultural pathogens, and further development is needed.

[0004] In recent years, the research on alkaloids in botanical pesticides has gradually deepened. Compared with traditional chemical pesticides, natural alkaloids have many advantages such as being degradable and safe for the environment, safe for higher animals and natural enemies, strong selectivity, and pests are not easy to develop resistance. They are suitable for development as bio-based pesticides. The structural optimization and modification of isobacterium alkaloids have shown high activity against plant bacterial diseases. This is of great significance for the development of agents for the prevention and control of plant bacterial diseases. Summary of the invention

[0005] In view of the above shortcomings, the present invention provides the use of isobacterium alkaloid derivatives in preventing and treating plant bacterial diseases. The isobacterium alkaloid derivatives show excellent inhibitory effects on rice bacterial blight and citrus canker. The specific technical scheme is as follows:

[0006] Application of isobacterium truncatum derivatives in preventing and controlling plant bacterial diseases, wherein the structural formula of the isobacterium truncatum derivatives is:

[0007]

[0008] Among them, R 1 , R 2, R 3 Independently selected from one of a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an amino group, a cyano group, a nitro group, a hydroxyl group, an alkoxy group, an aryl group, a heteroaryl group, and a heterocyclic group.

[0009] Preferably, in the above application, the plant bacterial diseases are one or more of Xanthomonas oryzae and Xanthomonas citri odoratus.

[0010] Preferably, in the above application, the structural formula of the isobenzamine derivative is any one of the following:

[0011]

[0012] On the other hand, the present invention also provides the use of isobacterium sulphate derivatives in the preparation of agents for preventing and treating plant bacterial diseases, wherein the effective active ingredients of the agents for preventing and treating plant bacterial diseases include isobacterium sulphate derivatives.

[0013] On the other hand, the present invention also provides an agent for preventing and treating plant bacterial diseases, wherein the agent for preventing and treating plant bacterial diseases comprises an isobacterium derivative and an adjuvant or an agronomically acceptable carrier, and the structural formula of the isobacterium derivative is:

[0014]

[0015] Among them, R 1 , R 2 , R 3 Independently selected from one of a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an amino group, a cyano group, a nitro group, a hydroxyl group, an alkoxy group, an aryl group, a heteroaryl group, and a heterocyclic group.

[0016] Preferably, in the above-mentioned agent for preventing and treating bacterial diseases of plants, the weight percentage of isobianine derivatives in the agent for preventing and treating bacterial diseases of plants is 1 to 99%.

[0017] Preferably, in the above-mentioned agent for preventing and controlling plant bacterial diseases, the dosage form of the agent for preventing and controlling plant bacterial diseases is a suspension concentrate, a wettable powder, an emulsifiable concentrate or a water-dispersible granule.

[0018] Preferably, in the above-mentioned agent for preventing and controlling plant bacterial diseases, the auxiliary agent comprises one or more of a wetting agent, a dispersant, an antifreeze agent, a thickener, a preservative, a defoaming agent, a filler, an emulsifier, an organic solvent, a binder, and a disintegrant.

[0019] Preferably, in the above-mentioned agent for preventing and controlling bacterial diseases of plants, the wetting agent is one or more of sodium dodecylbenzene sulfonate, alkyl polyoxyethylene ether, phenethylphenol polyoxyethylene ether phosphate, sodium dodecyl sulfate, and phenethylphenol polyoxyethylene ether phosphate; the dispersant is one or more of alkyl naphthalene sulfonate, phosphate ester salt, alkylphenol polyoxyethylene ether formaldehyde condensate, alkylphenol polyoxyethylene ether formaldehyde condensate, sodium lignin sulfonate, and sodium naphthalene sulfonate.

[0020] Preferably, in the above-mentioned agent for preventing and controlling plant bacterial diseases, the thickener is one or more of xanthan gum and magnesium aluminum silicate, the defoaming agent is silicone, and the emulsifier is one or more of alkylbenzene polyoxyethylene ether phosphate and calcium dodecylbenzene sulfonate.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The present invention obtains isobanine derivatives by structurally modifying isobanine, which have an inhibitory effect on plant bacterial diseases, especially on rice bacterial blight and citrus canker, which is significantly better than the control drugs thiabendazole and thiophanate-methyl, has high inhibitory activity, is extremely valuable in preventing and controlling plant pathogenic bacteria, and can be applied to the development of biogenic pesticides.

[0023] 2. The isoflavone derivatives of the present invention have the characteristics of simple synthesis process steps and green and high efficiency, which are conducive to large-scale production and promotion and application in the prevention and treatment of agricultural bacterial pathogens. DETAILED DESCRIPTION

[0024] The specific embodiments of the present invention are described in detail below, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments. Unless otherwise defined, all professional terms used hereinafter have the same meaning as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the protection scope of the present invention. Unless otherwise specifically stated, various raw materials, reagents, instruments and equipment used in the present invention, etc. can be purchased from the market or can be prepared by existing methods.

[0025] The synthetic route of the isoflavone derivative of the present invention is:

[0026]

[0027] Example 1

[0028] An isoflavone derivative Me-1, the structural formula is:

[0029]

[0030] The synthesis method comprises the following steps:

[0031] The compound oxolinic acid (31.3 mmol) was suspended in anhydrous methanol (450 mL), and a solution of sodium borohydride (127 mmol) in anhydrous methanol (50 mL) was slowly added. After the reaction mixture was mixed, p-toluenesulfonic acid monohydrate was added as a catalyst and heated at 65 degrees Celsius for 1 hour. After vacuum concentration, it was extracted three times with ethyl acetate and water, and anhydrous Na 2 SO 4 Drying and concentration gave the intermediate.

[0032] The intermediate (52mmol) and phenylhydrazine hydrochloride (58mmol) were placed in n-butanol (100mL), and 26mL of concentrated hydrochloric acid was added after heating. Reflux for 20 hours, cool and refrigerate overnight. The yellow solid obtained was collected by filtration, dissolved in water, and the pH was adjusted to 8-9 with 10% sodium hydroxide to obtain a free base. Dichloromethane and methanol (20:1) were used as eluents, and the target product Me-1 was purified by silica gel column with a yield of 37%.

[0033] Me-1: Yield: 37%; yellow solid; 1 H NMR (400MHz, CDCl3) δ8.41(d,J=15.8Hz,1H),8.02(d,J=17.5Hz,1H),7.93(t,J=7.4Hz,1H),7.89–7.79(m,1H),7.53(dt,J=14. 9,7.3Hz,1H),7.29(p,J=7.7Hz,1H),7.17(s,1H),6.18(d,J=15.8Hz,2H),4.36(h,J=7.5Hz,2H),1.52(q,J=8.1Hz,3H).MS-ESI m / z:291.1117[M+H] + .

[0034] Example 2

[0035] An isobryophyline derivative Mb-1, the structural formula is:

[0036]

[0037] The synthesis method is the same as that in Example 1, except that the oxolinic acid in Example 1 is replaced by cyclopropylcarboxylic acid.

[0038] Mb-1: yield: 35%; yellow solid; 1H NMR(600MHz,MeOD)δ9.65(s,1H),8.81(d,J=6.4Hz,1H),8.52(d,J=9.0Hz,1H),8.31(d,J=7.8Hz,1H),7.81(d,J=8.1Hz,1H),7 .62(ddd,J=8.3,7.2,1.2Hz,1H),7.49–7.43(m,1H),4.16(tt,J=7.4,4.0Hz,1H),1.62–1.56(m,2H),1.48–1.42(m,2H).MS-ESI m / z:311.0786[M+H] + .

[0039] Example 3

[0040] An isobryophyline derivative Mb-2, having the structural formula:

[0041]

[0042] The synthesis method is the same as that in Example 2, except that the phenylhydrazine hydrochloride in Example 2 is replaced by 2-fluorophenylhydrazine hydrochloride.

[0043] Mb-2: yield: 31%; yellow solid; 1 H NMR (400 MHz, DMSO-D 6 )δ9.40(s,1H),8.62–8.50(m,2H),8.07–8.00(m,1H),7.24–7.14(m,2H),4.01(t t,J=7.1,4.0Hz,1H),1.38(dd,J=7.3,5.2Hz,2H),1.29(p,J=4.3Hz,2H).MS-ESI m / z:329.0720[M+H] + .

[0044] Example 4

[0045] An isobryophyline derivative Mb-3, the structural formula is:

[0046]

[0047] The synthesis method is the same as that in Example 2, except that the phenylhydrazine hydrochloride in Example 2 is replaced by 3-fluorophenylhydrazine hydrochloride.

[0048] Mb-3: yield: 38%; yellow solid; 1 H NMR (400 MHz, CDCl 3)δ8.67(d,J=23.1Hz,1H),8.40–8.29(m,2H),7.88(dd,J=8.5,5.4Hz,1H),7.47–7.40(m,1H), 7.06–6.93(m,1H),3.80(tt,J=7.2,4.0Hz,1H),1.61–1.48(m,2H),1.29–1.21(m,2H).MS-ESI m / z:329.0788[M+H] + .

[0049] Example 5

[0050] An isobryophyline derivative Mb-5, the structural formula is:

[0051]

[0052] The synthesis method is the same as that in Example 2, except that the phenylhydrazine hydrochloride in Example 2 is replaced by 4-trifluoromethoxyphenylhydrazine hydrochloride.

[0053] Mb-5: yield: 36%; yellow solid; 1 H NMR (400 MHz, CDCl 3 )δ8.84–8.76(m,1H),8.38(ddd,J=23.4,11.1,5.8Hz,2H),7.88–7.74(m,2H),7.37(dt,J= 12.6,5.7Hz,1H),3.86–3.76(m,1H),1.55(q,J=6.7Hz,2H),1.31(d,J=7.3Hz,3H).MS-ESI m / z:395.0664[M+H] + .

[0054] Example 6

[0055] An isobryophyline derivative Mb-7, the structural formula is:

[0056]

[0057] The synthesis method is the same as that in Example 2, except that the phenylhydrazine hydrochloride in Example 2 is replaced by 4-chlorophenylhydrazine hydrochloride.

[0058] Mb-7: yield: 32%; yellow solid; 1 H NMR (400 MHz, DMSO-D 6)δ9.54(d,J=4.3Hz,1H),8.61(ddd,J=23.5,7.9,2.3Hz,2H),8.39(t,J=1.9Hz,1H),7.78(d,J=8.6Hz,1 H),7.46(dt,J=8.6,2.0Hz,1H),4.09(s,1H),1.43(dd,J=7.4,5.2Hz,2H),1.34(d,J=4.1Hz,2H).MS-ESI m / z:345.0432[M+H] + .

[0059] Example 7

[0060] An isobryophyline derivative Mb-8, the structural formula is:

[0061]

[0062] The synthesis method is the same as that in Example 2, except that the phenylhydrazine hydrochloride in Example 2 is replaced by 4-bromophenylhydrazine hydrochloride.

[0063] Mb-8: yield: 33%; yellow solid; 1 H NMR (400 MHz, DMSO-D 6 )δ9.58(s,1H),8.65(d,J=6.4Hz,1H),8.58(d,J=9.2Hz,1H),8.53(s,1H),7.71 (d,J=8.6Hz,1H),7.56(d,J=8.7Hz,1H),4.08(s,1H),1.50–1.30(m,4H).MS-ESI m / z:390.9920[M+H] + .

[0064] Comparative Example 1

[0065] A isoflavone derivative Mg-1, the structural formula is:

[0066]

[0067] The synthesis method is the same as that in Example 1, except that oxolinic acid in Example 1 is replaced by nalidixic acid.

[0068] Mg-1: yield: 33%; yellow solid; 1H NMR(400MHz, CDCl3)δ9.05(s,1H),8.97(dd,J=8.1,1.8Hz,1H),8.07(d,J=7.7Hz,1H),7.82(d,J=8.1Hz,1H),7.62–7 .48(m,2H),7.34(t,J=7.4Hz,1H),4.90(q,J=7.3Hz,2H),2.80(t,J=2.0Hz,3H),1.62(td,J=7.2,1.8Hz,3H).MS-ESI m / z:262.1331[M+H] + .

[0069] Comparative Example 2

[0070] An isoflavone derivative Mm-1, the structural formula is:

[0071]

[0072] The synthesis method is the same as that in Example 1, except that the oxolinic acid in Example 1 is replaced by ciprofloxacin.

[0073] Mm-1: yield: 39%; yellow solid; 1 H NMR (400MHz, CDCl3) δ8.71–8.56(m,1H),8.28(t,J=9.6Hz,1H),7.99(t,J=9.4Hz,1H),7.82(t,J=9.7Hz,1H),7.65(t,J=9.5Hz,1H),7.61–7.43(m,1H) ,7.31(t,J=7.5Hz,1H),3.77(tt,J=8.4,4.8Hz,1H),3.38–3.26(m,4H),3.2 3–3.08(m,4H),1.51(dq,J=13.6,7.0Hz,2H),1.24(d,J=4.7Hz,2H).MS-ESI m / z:361.1931[M+H] + .

[0074] The isobenzine derivatives described in the present invention are isobenzine derivatives obtained according to the synthesis method reported in the literature, and the pure products are separated by conventional methods such as silica gel column chromatography. The structures of the isobenzine derivatives are determined by nuclear magnetic resonance spectroscopy, mass spectrometry and other techniques.

[0075] Test Example 1 Determination of the activity of isoflavone derivatives against agricultural pathogenic bacteria

[0076] (1) Test agents: the isoflavone derivatives Ma-1 to Mm-1 in Examples 1 to 7 and Comparative Examples 1 to 3.

[0077] (2) Test bacteria: Xanthomonas oryzae ACCC 11602, the pathogen of rice bacterial blight, and Xanthomonas axonopodis pv. Citri, the pathogen of citrus canker, were provided by Gansu Academy of Agricultural Sciences.

[0078] (3) Antibacterial activity test:

[0079] The strain used in this experiment was frozen in the laboratory at -80℃ with 30% glycerol. Take out the frozen strains, streak them on NB solid medium (beef extract: 3g, peptone: 5g, yeast powder: 1g, sucrose: 10g, agar: 15g, distilled water: 1L, pH7.0; sterilized at 121℃ for 20min), and culture them at 28℃ until single colonies grow. Pick single colonies on the solid medium and transfer them to NB liquid medium (beef extract: 3g, peptone: 5g, yeast powder: 1g, sucrose: 10g, distilled water: 1L; sterilized at 121℃ for 20min), and culture them on a constant temperature shaker at 28℃ and 180rpm until they reach the logarithmic growth phase. Dilute the strains in the logarithmic growth phase with NB liquid medium to about 106CFU / mL for later use. Dissolve the isoflavone derivatives to be tested in appropriate amounts of DMSO to prepare a 20,000 μg / mL solution, add it to the liquid culture medium, mix well, and prepare a drug-containing liquid culture medium with a concentration of 200 μg / mL. Take 50 μL of the drug-containing culture medium and 50 μL of bacterial culture containing about 106 CFU / mL and add them to the wells of the 96-well plate, so that the final concentration of isoflavone derivatives is 100 μg / mL. 100 μL of the above-mentioned diluted bacterial solution containing an equal amount of DMSO is used as a control. The 96-well plate was cultured in a constant temperature incubator at 28°C for 48 hours until the bacterial solution of the control group grew out, and the OD value (OD600) of the bacterial solution in the well was measured using an enzyme marker. In addition, the OD values ​​of 100 μL of liquid culture medium and a drug with a concentration of 100 μg / mL were measured to correct the OD values ​​caused by the culture medium and the drug itself. The calculation formula for the corrected OD value and inhibition rate is as follows:

[0080] Corrected OD value = OD value of bacterial culture medium - OD value of sterile culture;

[0081] Inhibition rate = (corrected control culture medium bacterial solution OD value - corrected drug-containing culture medium OD value) / corrected control culture medium bacterial solution OD value × 100%

[0082] All experiments were repeated three times, and the inhibition rates of isoflavone derivatives were measured and are shown in Table 1.

[0083] It can be seen from the test results in Table 1 that the isobacterine derivatives of the present invention exhibit high antibacterial activity against Xanthomonas oryzae and Xanthomonas citri odoratus.

[0084] Table 1 Inhibition rate of isoflavone derivatives on plant pathogenic bacteria at 100 μg / mL (%)

[0085]

[0086] The drug-containing liquid culture medium of isoflavone derivatives was diluted by the two-fold dilution method in a 96-well plate to obtain a series of drug-containing culture media with concentrations of 50, 25, 12.5, 6.25, 3.12 μg / mL... The inhibition rates corresponding to different concentrations were determined according to the same experimental method as above. Thiabendazole and thiophanate-methyl control groups were set up. All experiments were repeated three times, and the MIC90 values ​​(the minimum drug concentration that inhibits 90% bacterial growth) of isoflavone derivatives were determined, as shown in Table 2.

[0087] From the test results in Table 2, it can be seen that the isobacterium derivatives prepared by the present invention show high inhibitory activity against two plant pathogenic bacteria, among which Mb-1, Mb-2, Mb-3, Mb-7, Mb-8 and Me-1 have the best activity, with MIC90 values ​​of 6.25-25 μg / mL for rice bacterial blight and 1.56-6.25 μg / mL for citrus canker bacteria, which are significantly better than the control drugs thiophanate-methyl and thiophanate-copper as well as comparative examples 1 and 2. The raw materials of the isobacterium-methyl derivatives of the present invention are easy to obtain and synthesize, and the antibacterial activity is significantly higher than that of the control drugs thiophanate-methyl and thiophanate-copper. These isobacterium-methyl derivatives have the value of further development and are expected to be developed into new agricultural antibacterial agents.

[0088] Table 2 MIC of isoflavone derivatives against plant pathogenic bacteria in vitro 90 (μg / mL)

[0089]

[0090] The following examples are different pesticide formulations containing isoflavone derivatives.

[0091] Example 8

[0092] 30% suspension concentrate of isoflavone derivative Mb-1, the formula is shown in Table 3.

[0093] The laboratory preparation method of the suspension concentrate is as follows: weigh the wetting agent, dispersant, antifreeze, preservative, defoamer, and deionized water according to the ratio, add them into a beaker and mix them evenly, then add the isoflavone derivative Mb-1 into the beaker, and then transfer it to a sand mill, add zirconium oxide beads into the sand mill, grind for 3 hours, add thickener xanthan gum and magnesium aluminum silicate and continue grinding for 0.5 hours, control the particle size D95 below 5 microns, filter to remove the zirconium oxide beads, and the suspension concentrate can be obtained.

[0094] Table 3 30% isoflavone derivative Mb-1 suspension formulation

[0095] Components Content (wt.%) Remark Isophylline derivative Mb-1 30 Active ingredients Phenylethylphenol polyoxyethylene ether phosphate 3 Wetting Agents Alkyl naphthalene sulfonate 2 First dispersant Phosphate salts 1.5 Second dispersant Propylene glycol 2 antifreeze Xanthan gum 0.8 First thickener Magnesium Aluminum Silicate 0.6 Second thickener Casson 1 preservative Silicone 0.5 Defoaming agent Deionized water Make up 100 filler

[0096] Example 9

[0097] 30% isoflavone derivative Mb-2 wettable powder, the formula is shown in Table 4.

[0098] The laboratory preparation method of wettable powder is as follows: weigh the isoflavone derivative Mb-2, wetting agent, dispersant and filler according to the proportion, add them into a food processor and mix them evenly, and then put them into a jet mill to grind them.

[0099] Table 4 30% isoflavone derivative Mb-2 wettable powder formulation

[0100] Components content(%) Remark Isophylline derivative Mb-2 30 Active ingredients Sodium Lauryl Sulfate 3 Wetting Agents Alkylphenol polyoxyethylene ether formaldehyde condensate 3 Dispersants White Carbon Black 2 filler Kaolin Make up 100 filler

[0101] Example 10

[0102] 50% isoflavone derivative Mb-3 emulsifiable concentrate, the formula is shown in Table 5.

[0103] The laboratory preparation method of emulsifiable concentrate is: mix the active ingredient, emulsifier, solvent, and filler, and stir until the active ingredient is completely dissolved and evenly stirred.

[0104] Table 5 50% isoflavone derivative Mb-3 emulsifiable concentrate formula

[0105] Components content(%) Remark Isophylline derivative Mb-3 50 Active ingredients Alkylbenzene polyoxyethylene ether phosphate 5.5 First emulsifier Calcium dodecylbenzenesulfonate 2.5 Second emulsifier Cyclohexanone 20 Solvents Xylene Make up 100 filler

[0106] Embodiment 11

[0107] 40% suspension of isoflavone derivative Mb-7, the formula is shown in Table 6.

[0108] The preparation steps are the same as those in Example 8.

[0109] Table 6 40% isoflavone derivative Mb-7 suspension formulation

[0110] Components content(%) Remark Isophylline derivative Mb-7 40 Active ingredients Phenylethylphenol polyoxyethylene ether phosphate 3 Wetting Agents Alkyl naphthalene sulfonate 2 First dispersant Phosphate 1.5 Second dispersant Propylene glycol 2 antifreeze Xanthan gum 0.8 First thickener Magnesium aluminum silicate 0.6 Second thickener Casson 1 preservative Silicone 0.5 Defoaming agent Deionized water Make up 100 filler

[0111] Example 12

[0112] 60% isobanthine derivative Me-1 water dispersible granules, the formula is shown in Table 7.

[0113] The laboratory preparation method of water-dispersible granules is as follows: weigh the isoflavone derivative Me-1, wetting agent, dispersant, disintegrant, binder and filler according to the ratio, add them into a food processor and mix them evenly, then put them into a jet mill for grinding, mix them again with a food processor, add an appropriate amount of water, and extrude and granulate them with a granulator.

[0114] The preparation method is the same as that of Example 8.

[0115] Table 7 60% isoflavone derivative Me-1 water dispersible granule formulation

[0116] Components content(%) Remark Isophylline derivative Me-1 60 Active ingredients Alkyl polyoxyethylene ether 1.5 Wetting Agents Sodium lignin sulfonate 3 First dispersant Sodium naphthalenesulfonate 2 Second dispersant Sodium chloride 2 Disintegrants Polyvinylpyrrolidone 2 Binder Kaolin Make up 100 filler

[0117] Comparative Example 3

[0118] 20% thiabendazole wettable powder, the formula is shown in Table 8.

[0119] The preparation steps are the same as those in Example 9.

[0120] Table 8 20% Thiacandazole wettable powder formulation

[0121]

[0122]

[0123] Test Example 2

[0124] Efficacy of drugs for controlling rice bacterial blight

[0125] Test agents: 30% isobacterium derivative Mb-1 suspension, 30% isobacterium derivative Mb-2 wettable powder, 50% isobacterium derivative Mb-3 emulsifiable concentrate, 40% isobacterium derivative Mb-7 suspension, 60% isobacterium derivative Me-1 water dispersible granules;

[0126] Control agent: 20% thiophanate-methyl suspension, 200 ml / mu, registration certificate PD20086024, Zhejiang Longwan Chemical Co., Ltd., commercially available; 100-130 g / mu

[0127] 20% thiocyanate wettable powder is homemade.

[0128] Test method: The test has 8 treatments, each with 3 replicates. The rice variety tested is Xinfeng No. 3, the concentration of the inoculated bacterial solution is 3×108cfu / mL, 60 seedlings are inoculated in each plot (marked), the blade of the scissors is dipped into the bacterial solution and the leaves are cut for inoculation, and the date of leaf cutting and inoculation is August 14, 2023. The test was applied 3 times, on August 15 (24h after artificial inoculation), August 25, and September 4 in the afternoon, using a 3WBD-20L backpack manual sprayer, and the dosage of the active ingredient (active ingredient) in each treatment was 40g / 667m 2 The water consumption for each spraying is 40kg / 667m 2 Before the application of the pesticide, there were sporadic white leaf diseased plants in the rice field.

[0129] No other fungicides were applied during the trial. A survey was conducted on September 25, 2023. Sampling was conducted at 5 points in each plot, and 6 seedlings were randomly surveyed at each point, for a total of 30 seedlings. The disease condition of the upper 3 functional leaves of each plant was graded, and the disease index and prevention efficacy were calculated using the grading standards.

[0130] The grading standards are as follows:

[0131] Grade 0: No disease;

[0132] Level 1: The leaf lesion area accounts for less than 10% of the leaf area;

[0133] Level 3: The leaf lesions account for 11-25% of the leaf area;

[0134] Level 5: The leaf lesions account for 26-45% of the leaf area;

[0135] Level 7: The leaf lesions account for 46-65% of the leaf area;

[0136] Level 9: The leaf spot area accounts for more than 65% of the leaf area.

[0137] Disease index (%) = [∑ (number of diseased leaves at each level × representative value at each level) / (total number of leaves surveyed × highest representative value)] × 100.

[0138] Relative efficacy (%) = (control disease index - treatment disease index) / control disease index × 100

[0139] As shown in Table 9, the control effects of the isobacterine derivatives of the present invention on rice bacterial blight are better than those of the control agents 20% thiabendazole wettable powder and 20% thiabendazole suspension.

[0140] Table 9 Field test results of rice bacterial blight control

[0141] Test drug Disease index Relative efficacy (%) 30% Compound Mb-1 Suspension 6.75 78.36 30% Compound Mb-2 wettable powder 7.90 74.67 50% Compound Mb-3 EC 8.07 74.14 40% Compound Mb-7 Suspension 7.74 75.20 60% Compound Me-1 Water Dispersible Granules 7.94 74.54 20% Thiacandazole wettable powder 11.85 62.01 20% Thiophanate-copper suspension 10.08 67.68 Blank control 31.19 /

[0142] Test Example 2

[0143] Efficacy of drugs for preventing and treating citrus canker

[0144] Test agents: 30% isobacterium derivative Mb-1 suspension, 30% isobacterium derivative Mb-2 wettable powder, 50% isobacterium derivative Mb-3 emulsifiable concentrate, 40% isobacterium derivative Mb-7 suspension, 60% isobacterium derivative Me-1 water dispersible granules;

[0145] Control agent: 20% thiophanate-methyl suspension, registration certificate PD20086024, Zhejiang Longwan Chemical Co., Ltd., commercially available.

[0146] 20% thiocyanate wettable powder, prepared in the laboratory.

[0147] Blank control: clean water

[0148] The test site is located in the suburb of Chongzuo, Nanning, where the soil fertility is average and the terrain is flat. The test variety is Wogan, which is 3 years old and growing well.

[0149] Experimental design and experimental methods: A field efficacy test on Wogan canker was conducted in a Wogan field in the suburbs of Chongzuo City, Nanning City. The pesticide was applied during the autumn shoot stage, focusing on the leaves, and spraying evenly on the front and back. A total of 8 treatment plots were set up in the experiment, each of which was arranged in random blocks. 15 Wogan plants were listed in the plot, and repeated 3 times. Use Yipengbao (capacity 16 kg) for spraying. The dosage of each agent is shown in Table 10. A total of 3 sprays were conducted on August 21, August 31, and September 10, 2023. The days during the application of the pesticide were mostly cloudy or overcast. No drug prevention and treatment of ulcer disease was performed in the blank control group.

[0150] Investigation method: Observe and record the occurrence of leaf canker on the 5th and 10th days after each spraying, investigate the prevention effect 10 days after the last spraying, and record relevant data. Use the diagonal sampling method, investigate 5 points at fixed points, investigate 1 citrus tree at each point, sample each tree at 5 points in the east, south, west, north, and center, investigate 1 branch at each point, investigate 20 new leaves on each branch, and record the number of diseased leaves at each level.

[0151] The grade of Wogan canker is divided according to the number of lesions on a single leaf. The grading standards are as follows:

[0152] Level 0: no disease;

[0153] Level 1: 1-5 lesions on each leaf;

[0154] Level 3: 6-10 lesions on each leaf;

[0155] Level 5: 11-15 lesions on each leaf;

[0156] Level 7: 16-20 lesions on each leaf;

[0157] Level 9: There are more than 21 lesions on each leaf.

[0158] Calculate the disease index and prevention effect according to the formula:

[0159] Disease index (%) = [∑ (number of diseased leaves at each level × representative value at each level) / (total number of leaves surveyed × highest representative value)] × 100.

[0160] Relative control effect (%) = (disease index of blank control area after application - disease index of treated area after application) / disease index of blank control area after application × 100.

[0161] The test results are shown in Table 10, from which it can be seen that the efficacy of the isoflavone derivatives of the present invention in preventing and treating citrus canker is significantly better than that of the control agents 20% thiabendazole wettable powder and 20% thiophanate-methyl suspension.

[0162] Table 10 Results of field efficacy test on the prevention and treatment of citrus canker

[0163] Test drug Dilution multiple Disease index Relative efficacy (%) 30% Compound Mb-1 Suspension 750 1.81 88.33 30% Compound Mb-2 wettable powder 750 2.02 86.94 50% Compound Mb-3 EC 1200 2.10 86.41 40% Compound Mb-7 Suspension 1000 1.21 92.15 60% Compound Me-1 Water Dispersible Granules 1500 2.21 85.74 20% Thiacandazole wettable powder 4.20 72.87 20% Thiophanate-copper suspension 500 3.16 79.57 Blank control / 15.48 /

[0164] In summary, the antibacterial activity of the isoflavone derivatives of the present invention against the pathogens of rice bacterial blight and citrus canker is higher than that of the commercially available control drugs thiabendazole and thiabendazole, and has excellent inhibitory activity. The synthesis method of the isoflavone derivatives is simple, and has high application potential, and can be further studied and developed in the prevention and control of plant pathogenic bacteria.

[0165] The foregoing description of specific exemplary embodiments of the present invention is for the purpose of illustration and demonstration. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is clear that many changes and variations can be made based on the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can realize and utilize various different exemplary embodiments of the present invention and various different selections and changes. The scope of the present invention is intended to be limited by the claims and their equivalents.

Claims

1. The use of isoflavone derivatives in preventing and treating plant bacterial diseases, characterized in that: The structural formula of the isobenzamine derivative is: Wherein, R1, R2, and R3 are independently selected from one of hydrogen atom, halogen atom, alkyl group, cycloalkyl group, amino group, cyano group, nitro group, hydroxyl group, alkoxy group, aryl group, heteroaryl group, and heterocyclic group.

2. The use according to claim 1, characterized in that: The plant bacterial diseases are one or more of Xanthoceras oryzae and Xanthoceras citri citri.

3. The use according to claim 2, characterized in that: The structural formula of the isobenzamine derivative is any one of the following:

4. Use of isoflavone derivatives in the preparation of agents for preventing and treating plant bacterial diseases, characterized in that: The effective active ingredients of the agent for preventing and treating bacterial diseases of plants include isobacterium truncatum derivatives.

5. A medicament for preventing and treating plant bacterial diseases, characterized in that: The agent for preventing and treating plant bacterial diseases comprises an isobacterium alkaloid derivative and an adjuvant or an agronomically acceptable carrier. The structural formula of the isobacterium alkaloid derivative is: Wherein, R1, R2, and R3 are independently selected from one of hydrogen atom, halogen atom, alkyl group, cycloalkyl group, amino group, cyano group, nitro group, hydroxyl group, alkoxy group, aryl group, heteroaryl group, and heterocyclic group.

6. The agent for preventing and treating plant bacterial diseases according to claim 5, characterized in that: The weight percentage of the isobenzamine derivative in the agent for preventing and treating plant bacterial diseases is 1-99%.

7. The agent for preventing and controlling plant bacterial diseases according to claim 5, characterized in that: The dosage form of the agent for preventing and controlling plant bacterial diseases is a suspension, a wettable powder, an emulsifiable concentrate or a water-dispersible granule.

8. The agent for preventing and controlling plant bacterial diseases according to claim 5, characterized in that: The auxiliary agent includes one or more of a wetting agent, a dispersant, an antifreeze agent, a thickener, a preservative, a defoaming agent, a filler, an emulsifier, an organic solvent, a binder, and a disintegrant.

9. The agent for preventing and treating plant bacterial diseases according to claim 8, characterized in that: The wetting agent is one or more of sodium dodecylbenzene sulfonate, alkyl polyoxyethylene ether, phenethylphenol polyoxyethylene ether phosphate, sodium dodecyl sulfate, and phenethylphenol polyoxyethylene ether phosphate; the dispersant is one or more of alkyl naphthalene sulfonate, phosphate ester salt, alkylphenol polyoxyethylene ether formaldehyde condensate, alkylphenol polyoxyethylene ether formaldehyde condensate, sodium lignin sulfonate, and sodium naphthalene sulfonate.

10. The agent for preventing and controlling plant bacterial diseases according to claim 8, characterized in that: The thickener is one or more of xanthan gum and magnesium aluminum silicate, the defoamer is silicone, and the emulsifier is one or more of alkylbenzene polyoxyethylene ether phosphate and calcium dodecylbenzene sulfonate.

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