Chromanone compound and application thereof in prevention and treatment of kiwifruit bacterial canker

Abstract

The invention discloses a chromanone compound and application thereof in prevention and treatment of kiwifruit bacterial canker, the structural formula of the chromanone compound is # imgabs0, in the formula, R is one or more of hydrogen, alkyl, alkenyl, alkynyl, nitro, alkoxy, cyano, amino, sulfonic group, halogenated alkyl, aryl, heteroaryl and halogen; r'is alkyl or aryl. According to the synthesis method provided by the invention, 2-hydroxyacetophenone which is low in price and easy to obtain is used as a basic raw material for conventional chemical synthesis, and the reaction can be completed under mild conditions without a metal catalyst. The synthesis method has the advantages of simple reaction system, short reaction time and high yield, and can be used for green synthesis of chromanone compounds; meanwhile, the chromanone compound has an obvious control effect on kiwifruit bacterial canker pathogen.

Description

Technical Field

[0001] The invention relates to the technical field of pesticides, and in particular to a chromanone compound and application thereof in the prevention and treatment of kiwifruit bacterial canker. Background Art

[0002] The pathogen of kiwifruit bacterial canker is Pseudomonas syringae pv. actinidiae, which has a wide host range, strong pathogenicity, rapid occurrence and difficulty in eradication. It can cause a large number of kiwifruit plants to die in a short period of time and has become the main limiting factor for the development of the kiwifruit industry. The pathogen mainly harms the new shoots, branches, leaves and buds of kiwifruit. After the plants are harmed, they will shrink and die, causing large-scale death of plants, seriously endangering the yield and quality of kiwifruit.

[0003] The existing prevention and control methods of kiwifruit canker mainly include cultivation management protection, breeding of highly resistant varieties, biological control and chemical control and other measures. Only by implementing unified prevention and control and comprehensive prevention and control can the harm of kiwifruit bacterial canker be minimized. Although there are various methods to prevent and control kiwifruit bacterial canker, chemical agents are still used as a major means of prevention and control. Therefore, the development of a safe, effective and novel new pesticide is of great significance for the prevention and control of kiwifruit canker.

[0004] Chromanone compounds have a variety of biological activities, including anti-inflammatory, antioxidant, antibacterial, etc., especially in the field of agricultural chemicals, chromanone skeleton compounds have many applications and have attracted much attention in recent years. A Chinese patent application document with publication number CN111943939A discloses a method for synthesizing chromanone compounds and their agricultural biological activity, which provides a new method, comprising adding 2-(allyloxy)benzaldehyde compounds and 2-hydroxyisoindoline-1,3-dione to a reactor respectively, and heating and reacting them in a closed manner at 50-100°C in air for 5-8 hours under the action of a catalyst and a low eutectic solvent; after the reaction, column chromatography is performed to obtain chromanone compounds, and the synthesized compounds can be used alone or in combination in the prevention and treatment of apple tree rot fungus Valsam ali and citrus anthracnose fungus Colletot ri chum gloeosporioides Penz, but the chromanone compounds disclosed therein have a complex structure and have not been used in the prevention and treatment of kiwifruit. It is still of great practical significance to further explore the simple synthesis of chromanones with novel structures and explore their activity in preventing and treating kiwifruit bacterial canker, and to develop safe and efficient candidate compounds. Summary of the invention

[0005] The technical problem to be solved by the present invention is how to safely and efficiently resist kiwifruit bacterial canker bacteria.

[0006] The present invention solves the above technical problems through the following technical means:

[0007] Application of a chromanone compound in the prevention and treatment of kiwi fruit bacterial canker, wherein the structural formula of the chromanone compound is Wherein, R is one or more of hydrogen, alkyl, alkenyl, alkynyl, nitro, alkoxy, cyano, amino, sulfonic acid, haloalkyl, aryl, heteroaryl, and halogen; and R′ is alkyl or aryl.

[0008] Preferably, R is hydrogen, C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, nitro, halogen, C1-C6 alkoxy, cyano, amino, sulfonic acid, halogenated C1-C6 alkyl, C6-C 10 One or more of aryl or 5-10 membered heteroaryl.

[0009] Preferably, R is one of hydrogen, halogen, and C1-C6 alkyl; and R′ is methyl or phenyl.

[0010] Preferably, the structural formula of the chromanone compound is

[0011] One of them.

[0012] The present invention also provides a chromanone compound, the structural formula of which is One of them.

[0013] Preferably, the chromanone compound has the structural formula One of them.

[0014] The present invention also provides a method for preparing the chromanone compounds, which comprises: One of the above-mentioned compounds and sodium methanesulfinate are used as raw materials, and sulfone substitution is carried out under acidic catalytic conditions to obtain the chromanone compound.

[0015] Preferably, the catalysis is carried out using an acid as a catalyst, and the acid is a common proton acid.

[0016] Preferably, the acid is a mixture of one or more of formic acid, acetic acid, hydrochloric acid, phosphoric acid, acetic acid, and p-toluenesulfonic acid.

[0017] The present invention also provides an application of the chromanone compounds in the preparation of products for resisting kiwifruit bacterial canker bacteria.

[0018] The invention also provides a product for resisting kiwifruit bacterial canker bacteria, which contains the chromanone compound.

[0019] Preferably, the product against kiwifruit bacterial canker uses an organic solvent as a dispersant.

[0020] Preferably, the concentration of chromanone compounds in the product against kiwifruit bacterial canker is 0.1-10 mg / mL.

[0021] The invention also provides an application of the product for resisting kiwifruit bacterial canker in preventing and treating kiwifruit bacterial canker.

[0022] In the present invention, in the preparation process of chromanone compounds, first, in an air atmosphere, an o-hydroxyacetophenone compound is used as a raw material and an amine salt is used as an additive, and a heating reaction is carried out in a tetrahydrofuran solvent to obtain an alkenyl intermediate, and the alkenyl intermediate is 3-substituted with a sodium sulfinate compound under acid catalysis to obtain a chromanone product. The synthesis route is as follows:

[0023]

[0024] Among them, polyformaldehyde provides a carbon unit to participate in the reaction to obtain chromanone compound 2, or other raw materials that can provide a carbon unit are all within the scope of protection of the present invention. The chromanone compound 2 reacts with a sulfinate under the action of an acid to obtain a 3-sulfone-substituted chromanone compound 3, and the sulfinate includes an alkyl, aryl or heteroaryl substituent or a directly corresponding sulfinic acid raw material.

[0025] Preferably, the additive is a common quaternary ammonium salt, such as a mixture of one or more of diisopropylamine hydrochloride, acetate, and trifluoroacetate.

[0026] Preferably, the reaction temperature is from room temperature to 120 degrees, and the reaction time is 2-24 hours.

[0027] Preferably, the intermediate 2 and the target product 3 are separated and purified by column chromatography, the stationary phase used in the column chromatography separation is a silica gel column, the eluent used for the intermediate 2 is petroleum ether: ethyl acetate in a volume ratio of 40:1, and the eluent used for the final product 3 is petroleum ether: ethyl acetate in a volume ratio of 5:1.

[0028] Compared with the prior art, the advantages of the present invention are:

[0029] The synthesis method provided by the present invention uses cheap and readily available 2-hydroxyacetophenones as basic raw materials for conventional chemical synthesis, and the reaction can be completed under mild conditions without the need for a metal catalyst. The synthesis method has a simple reaction system, a short reaction time, and a high yield, and can synthesize chromanone compounds in a green manner; at the same time, chromanone compounds have an obvious preventive and therapeutic effect on kiwifruit bacterial canker bacteria. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is the H NMR spectrum of compound 3a prepared in Example 1 of the present invention;

[0031] Figure 2 is the NMR carbon spectrum of compound 3a prepared in Example 1 of the present invention;

[0032] Figure 3 is the H NMR spectrum of compound 3b prepared in Example 2 of the present invention;

[0033] Figure 4 is the NMR carbon spectrum of compound 3b prepared in Example 2 of the present invention;

[0034] Figure 5 is the H NMR spectrum of compound 3c prepared in Example 3 of the present invention;

[0035] Figure 6 is the NMR carbon spectrum of compound 3c prepared in Example 3 of the present invention;

[0036] Figure 7 is the H NMR spectrum of compound 3d prepared in Example 4 of the present invention;

[0037] Figure 8 is the NMR carbon spectrum of compound 3d prepared in Example 4 of the present invention;

[0038] Fig. 9 is the H NMR spectrum of compound 3e prepared in Example 5 of the present invention;

[0039] Fig.10 is the NMR carbon spectrum of compound 3e prepared in Example 5 of the present invention;

[0040] Fig.11 The antibacterial results of compound 2b and compound 3b prepared in the examples of the present invention on kiwifruit tissue culture seedlings immersed in bacterial solution are shown in FIG.

[0041] Fig.12 The colony count of the leaves of kiwifruit tissue culture seedlings treated with compound 2b prepared in the example of the present invention after being immersed in bacterial solution;

[0042] Fig.13The colony count of the leaves of kiwifruit tissue culture seedlings treated with compound 3b prepared in the example of the present invention after being immersed in bacterial solution. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] Unless otherwise specified, the test materials and reagents used in the following examples can be obtained from commercial sources.

[0045] If no specific techniques or conditions are specified in the examples, they can be carried out according to the techniques or conditions described in the literature in the art or according to the product instructions.

[0046] The preparation of the diisopropylamine trifluoroacetic acid complex salt described below comprises the following steps: adding trifluoroacetic acid to a mixture of diisopropylamine in tert-butyl methyl ether at 0° C., wherein the molar ratio of diisopropylamine to trifluoroacetic acid is 1:1, stirring the reaction mixture at 0° C. for 10 minutes, and concentrating under reduced pressure to remove excess solvent to obtain a pure white crystalline salt, namely the diisopropylamine trifluoroacetic acid complex salt.

[0047] The intermediates and target products are separated and purified by column chromatography. The stationary phase used in the column chromatography separation is a silica gel column. The eluent used for the intermediates (2a, 2b, 2d, 2e) is petroleum ether: ethyl acetate in a volume ratio of 40:1, and the eluent used for the target products (3a-e) is petroleum ether: ethyl acetate in a volume ratio of 5:1.

[0048] Example 1

[0049] Synthesis method of compound 3a:

[0050]

[0051] First, the synthesis of chromanone compound 2a was carried out according to the literature (Chem. Commun., 2010, 46, 1715-1717). In a 100 mL round-bottom flask, o-hydroxyacetophenone (1.0 mmol, 120 μL), diisopropylamine trifluoroacetic acid complex salt (1.1 mmol, 238 mg), and paraformaldehyde (4.0 mmol, 120 mg) were dissolved in 4.0 mL of tetrahydrofuran solution. The mixture was stirred at 60° C. for 3 hours. After the reaction was completed, it was cooled to room temperature. The mixture was concentrated by rotary evaporator and purified by column chromatography to obtain light yellow oily chromanone compound 2a (107 mg, 67% yield). The NMR data was consistent with the literature.

[0052] Compound 2a (0.67 mmol, 107 mg) was dissolved in 5.0 mL of ethanol solution, sodium methanesulfinate (1.0 mmol, 104 mg) and p-toluenesulfonic acid monohydrate (0.54 mmol, 103 mg) were added, and stirred at 60°C for 6 hours. After the reaction was completed, the mixture was cooled to room temperature, and the mixture was concentrated by rotary evaporator and purified by column chromatography to obtain white solid 3a (134 mg, 83% yield). The structure of the compound was tested by NMR spectrum as shown in Figure 1-2 The specific results are as follows: 1 H NMR (600MHz, CDCl3) δ7.87(d,J=7.8Hz,1H),7.51(t,J=7.2Hz,1H),7.04(t,J=7.2Hz,1H),7.00(d,J=8.4Hz,1H),4.89(dd,J=10.8Hz,J=4.8Hz, 1H), 4.33 (dd, J = 12.0Hz, J = 10.8Hz, 1H), 3.87 (dd, J = 14.4Hz, J = 2.4Hz, 1H), 3.52-3.54 (m, 1H), 3.04 (s, 3H), 2.92 (dd, J = 14.4Hz, J = 8.4Hz, 1H); 13 C{H}NMR (150MHz,CDCl3)δ190.5,161.9,136.8,127.6,122.0,120.1,118.2,69.9,50.6,42.1,41.0. The synthesized compound was identified as target compound 3a by NMR analysis.

[0053] Example 2

[0054] Synthesis method of compound 3b:

[0055]

[0056] Referring to the synthesis of compound 2a, in a 100 mL round-bottom flask, 5-fluoro-2-hydroxyacetophenone (1.0 mmol, 154 mg), diisopropylamine trifluoroacetic acid complex salt (1.1 mmol, 238 mg), and paraformaldehyde (4.0 mmol, 120 mg) were dissolved in 4.0 mL of tetrahydrofuran solution, and the mixture was stirred at 60 ° C for 3 hours. After the reaction was completed, it was cooled to room temperature. The mixture was concentrated by rotary evaporator and purified by column chromatography to obtain a light yellow oily intermediate 2b (109 mg, 61% yield).

[0057] The intermediate 2b (0.61mmol, 109mg) was dissolved in 5.0mL of ethanol solution, and sodium methanesulfinate (0.92mmol, 96mg) and p-toluenesulfonic acid monohydrate (0.49mmol, 93mg) were added, and stirred at 60°C for 6 hours. After the reaction was completed, the mixture was cooled to room temperature, and the mixture was concentrated by rotary evaporator and purified by column chromatography to obtain a white solid 3b (124mg, 79% yield). The structure of the compound was tested by NMR spectrum as shown in Figure 3-4 The data results are as follows: 1 H NMR (600MHz, CDCl3) δ7.54 (dd, J=7.8Hz, J=3.0Hz, 1H), 7.24-7.25 (m, 1H), 7.00 (dd, J=9.0Hz, J=4.2Hz, 1H), 4.91 (dd, J=11.4Hz, J=5.4Hz, 1H ), 4.33 (dd, J = 12.0Hz, J = 11.4Hz, 1H), 3.86 (dd, J = 14.4Hz, J = 3.6Hz, 1H), 3.52-3.57 (m, 1H), 3.05 (s, 3H), 2.94 (dd, J = 14.4Hz, J = 8.4Hz, 1H); 13 C{H}NMR (150MHz,CDCl3)δ189.9,158.4,157.5(d,J=222.0Hz),124.5(d,J=24.0Hz),120.5(d,J=6.0Hz),120.0(d,J=7.5Hz),112.5(d,J=24Hz),70.1,50.5,42.2,40.9. The synthesized compound was identified as target compound 3b by NMR analysis.

[0058] Example 3

[0059] Synthesis method of compound 3c:

[0060]

[0061] The intermediate 2a (0.5mmol, 80mg) was dissolved in 5.0mL of ethanol solution, and sodium benzenesulfinate (0.75mmol, 123mg) and p-toluenesulfonic acid monohydrate (0.4mmol, 76mg) were added, and stirred at 60°C for 6 hours. After the reaction was completed, the mixture was cooled to room temperature, and the mixture was concentrated by rotary evaporator and purified by column chromatography to obtain a white solid 3c (50mg, 33% yield). The structure of the compound was tested by NMR spectrum as shown in Figure 5-6 The data results are as follows: 1 H NMR (600MHz, CDCl3) δ7.97(d,J=7.8Hz,2H),7.83(d,J=7.8Hz,1H),7.69(t,J=7.2H z,1H),7.60(t,J=7.2Hz,2H),7.50(t,J=7.2Hz,1H),7.01(dd,J=17.4Hz,J=7.2Hz, 2H),5.00(dd,J=11.4Hz,J=5.4Hz,1H),4.35(dd,J=11.4Hz,J=10.8Hz,1H),3.98(d d, J=15.0Hz, J=3.6Hz, 1H), 3.39-3.44 (m, 1H), 3.01 (dd, J=15.0Hz, J=10.2Hz, 1H); 13 C{H}NMR (150MHz,CDCl3)δ190.0,161.9,139.2,136.7,134.3,129.7,128.1,127.7,121.9,120.1,118.2,69.8,52.0,41.1. The synthesized compound was identified as target compound 3c by NMR analysis.

[0062] Example 4

[0063] Synthesis method of compound 3d:

[0064]

[0065] Referring to the synthesis of compound 2a, in a 100 mL round-bottom flask, 5-methyl-2-hydroxyacetophenone (1.0 mmol, 150 mg), diisopropylamine trifluoroacetic acid complex salt (1.1 mmol, 238 mg), and paraformaldehyde (4.0 mmol, 120 mg) were dissolved in 4.0 mL of tetrahydrofuran solution, and the mixture was stirred at 60 ° C for 3 hours. After the reaction was completed, it was cooled to room temperature. The mixture was concentrated by rotary evaporator and purified by column chromatography to obtain a light yellow oily intermediate 2d (120.0 mg, 69% yield).

[0066] The intermediate 2d (0.69 mmol, 120 mg) was dissolved in 5.0 mL of ethanol solution, and sodium methanesulfinate (1.04 mmol, 108 mg) and p-toluenesulfonic acid monohydrate (0.55 mmol, 105 mg) were added, and stirred at 60°C for 6 hours. After the reaction was completed, the mixture was cooled to room temperature, and the mixture was concentrated by rotary evaporator and purified by column chromatography to obtain a white solid 3d (142 mg, 81% yield). The structure of the compound was tested by NMR spectrum as shown in Figure 7-8 The data results are as follows: 1 H NMR (600MHz, CDCl3) δ7.67(s,1H),7.33(d,J=8.4Hz,1H),6.91(d,J=8.4Hz,1H),4.86(dd,J=10.8Hz,J=5.4Hz,1H),4.30(dd,J=11.4H z,J=10.8Hz,1H),3.87(dd,J=14.4Hz,J=2.4Hz,1H),3.49-3.53(m,1H),3.04(s,3H),2.92(dd,J=14.4Hz,J=8.4Hz,1H),2.31(s,3H); 13 C{H}NMR (150MHz,CDCl3)δ190.6,159.8,137.8,131.4,130.0,119.5,117.8,69.7,50.6,41.9,40.9,20.3. The synthesized compound was identified as target compound 3d by NMR analysis.

[0067] Example 5

[0068] Synthesis method of compound 3e:

[0069]

[0070] Referring to the synthesis of compound 2a, in a 100 mL round-bottom flask, 1-(3-hydroxy-5,6,7,8-tetrahydro-2-naphthalene)-ethanone (1.0 mmol, 190 mg), diisopropylamine trifluoroacetic acid complex salt (1.1 mmol, 238 mg), and paraformaldehyde (4.0 mmol, 120 mg) were dissolved in 4.0 mL of tetrahydrofuran solution, and the mixture was stirred at 60 ° C for 3 hours. After the reaction was completed, it was cooled to room temperature. The mixture was concentrated by rotary evaporator and purified by column chromatography to obtain a light yellow oily intermediate 2e (131 mg, 61% yield).

[0071] The intermediate 2e (0.61 mmol, 131 mg) was dissolved in 5.0 mL of ethanol solution, and sodium methanesulfinate (0.92 mmol, 96 mg) and p-toluenesulfonic acid monohydrate (0.49 mmol, 93 mg) were added, and stirred at 60°C for 6 hours. After the reaction was completed, the mixture was cooled to room temperature, and the mixture was concentrated by rotary evaporator and purified by column chromatography to obtain a white solid 3e (138 mg, 77% yield). The structure of the compound was tested by NMR spectrum as shown in Figure 9-10 The data results are as follows: 1 H NMR (600MHz, CDCl3) δ7.56 (s, 1H), 6.69 (s, 1H), 4.82 (dd, J = 10.8Hz, J = 5.4Hz, 1H), 4.26 (dd, J = 11.4Hz, J = 10.8Hz, 1H), 3.85 (dd, J = 1 4.4Hz,J=3.0Hz,1H),3.44-3.48(m,1H),3.03(s,3H),2.91(dd,J=14.4Hz,J=8.4Hz,1H),2.74(d,J=29.4Hz,4H),1.76-1.77(m,4H); 13 C{H}NMR (150MHz,CDCl3)δ190.5,159.5,148.1,131.4,127.4,118.0,117.5,69.8,50.8,42.0,30.2,28.6,23.1,22.7. The synthesized compound was identified as target compound 3e by NMR analysis.

[0072] Example 6

[0073] Antibacterial activity test

[0074] The filter paper diffusion method was used to detect the control effect of a series of synthesized target compounds on kiwifruit bacterial canker (Pseudomonas syringae pv. Actinidiae). Since the synthesized chromone compounds have good stability at room temperature and are insoluble in water, the compounds were dissolved in acetone and prepared to a concentration of 6.0 mg / mL, with acetone and gentamicin sulfate as negative and positive controls, respectively. The organic phase was filtered and sterilized with a sterile 0.2 μm diameter microporous filter membrane, and the filter paper was punched into several filter paper discs with a single-hole punch with a diameter of 6 mm for sterilization. Kiwifruit bacterial canker was inoculated into LB solid culture medium by streaking method and placed in a 37°C constant temperature incubator for 24 hours for activation. Then take 5mL of LB liquid into a 10.0mL shaking tube, use an inoculation loop to pick up a small amount of bacteria and mix them in the LB liquid shaking tube, incubate in a shaker at 37°C and 180r / min for 8-10h, and use a turbidimeter to adjust the concentration of the bacterial suspension to about 10 6CFU / mL, take 100μL of bacterial suspension with a pipette and add it to 100mL of 50-60℃ Luria-Bertani (LB) medium, mix well and pour into a plate. After the bacteria-containing LB plate solidifies, stick a sterile filter paper on the plate, add 5μL of the target compound solution, gentamicin sulfate or acetone to each filter paper, and finally culture the plate in a 37℃ incubator for 24-36h. Finally, the cross-cross method is used to measure the diameter of the inhibition zone (IZD, in mm) to evaluate the antibacterial activity, with three replicates in each group to determine the antibacterial effect of the compound.

[0075] Table 1 shows the antibacterial activity of seven chromone compounds at a concentration of 30 μg / filter paper against kiwifruit bacterial canker bacteria

[0076] Table 1

[0077]

[0078] Note: Gentamycin sulfate was used as a positive control for pathogenic bacteria; negative controls had no inhibitory activity; the results were expressed as mean ± standard deviation; the test concentration was 30 μg / filter paper.

[0079] From Table 1 above, it can be seen that the compounds of the present invention have a good inhibitory effect on kiwi fruit bacterial canker bacteria.

[0080] Compounds 2b and 3b with better antibacterial effects were selected for the kiwifruit tissue culture seedlings immersion experiment

[0081] Test materials: 'Hongyang' kiwifruit tissue culture seedlings, compound 2b, compound 3b

[0082] Test methods and steps:

[0083] (1) Preparation of tissue culture seedling subculture medium: weigh 800 mL of pure water, adjust the pH to 5.8, add 800 μL of NAA (1 mg / mL) aqueous solution and 800 μL of 6-BA (3 mg / mL) aqueous solution, and sterilize at high temperature (121°C, 15 min);

[0084] (2) Drug concentration setting: The two compounds were dissolved in acetone and prepared into concentrations of 3 mg / mL, 600 μg / mL, and 300 μg / mL, respectively;

[0085] (3) Culture medium setting: In a clean bench, seven groups of 100 mL subculture medium were weighed respectively. One group of ordinary subculture medium (without any drug added) was set up, and the remaining six groups were added with 100 μL of intermediate compound 2b (3 mg / mL), 100 μL of intermediate compound 2b (600 μg / mL), 100 μL of intermediate compound 2b (300 μg / mL), 100 μL of final product compound 3b (3 mg / mL), 100 μL of final product compound 3b (600 μg / mL), and 100 μL of final product compound 3b (300 μg / mL). Each group was poured into three sterile tissue culture subculture bottles and naturally cooled and solidified.

[0086] (4) Subculturing of tissue culture seedlings: In a clean bench, use sterilized tweezers (286°C, 20 min, natural cooling) to select healthy and disease-free 'Hongyang' tissue culture seedlings and insert them obliquely into the culture medium;

[0087] (5) Tissue culture seedling cultivation: 25°C, 16 h light, 8 h dark, 45 days;

[0088] (6) Inoculation of tissue culture seedlings: Take out the kiwifruit canker strain JF8 stored at -80°C, thaw at room temperature, and then streak on LB medium to activate the strain. After culturing on the plate for 2 days, pick out a single clone and add it to a 2mL centrifuge tube with LB liquid culture medium. Culture at 28°C and 200r / min with shaking for 12 hours. Centrifuge the activated bacterial solution at 6000rpm for 5 minutes, remove the supernatant and collect the bacteria. Use a pipette to draw 1mL of pre-sterilized PBS to resuspend the bacteria, gently break up the precipitate to make the bacteria completely suspended, and measure the bacterial solution OD600nm = 0.2. In the clean bench, open the tissue culture seedlings that have been cultured for 45 days, add the bacterial solution with adjusted OD, ensure that the whole seedling is immersed in the bacterial solution, and pour out the bacterial solution after 5 minutes. The seedlings were cultured at 25°C, 16h light, 8h dark, and 7d. The experimental results of tissue culture seedlings are as follows Fig.11 As shown by Fig.11 It can be seen that compound 2b at 600 μg / mL and compound 3b at 3 mg / mL showed the best antibacterial activity in kiwifruit tissue culture seedlings.

[0089] (7) The colony counting method is as follows:

[0090] Take a piece of diseased leaf of the same size after inoculation of WT strain (without adding any drug) and strains treated with different drugs, add 1 mL of sterile PBS solution, grind with a grinding mortar until homogenized, and then transfer to a 1.5 mL centrifuge tube to obtain grinding solution;

[0091] The grinding solution was diluted with PBS solution to a bacterial concentration of 10 -7 (Dilution from 10 -1 , 10 -2, 10 -3 , 10 -4 , 10 -5 , 10 -6 , 10 -7 ), during which the liquid must be fully mixed to prevent the bacteria from adhering to the bottom of the centrifuge tube;

[0092] Take 5 μL of the sample solution at each concentration gradient in the clean bench, slowly spot the sample solution on the LB culture plate, let it stand until the surface is dry, seal it and invert it in a 28℃ incubator for 2 days. Take out the culture plate after 2 days of culture, take pictures and count them. The results are as follows Fig.12 and 13 As shown in the figure, from left to right, the bacterial concentration is 10 -1 , 10 -2 , 10 -3 , 10 -4 , 10 -5 , 10 -6 , 10 -7 ,Depend on Fig.12 and 13 It can be seen that when compound 2b is at 600 μg / mL and compound 3b is at 3 mg / mL, the number of kiwifruit canker colonies in the leaves of kiwifruit tissue culture seedlings is the least, that is, the antibacterial activity of compound 2b is optimal when the concentration is 600 μg / mL and compound 3b is at 3 mg / mL.

[0093] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An application of chromanone compounds in the prevention and treatment of kiwi fruit bacterial canker, characterized in that: The structural formula of the chromanone compound is Wherein, R is one or more of hydrogen, alkyl, alkenyl, alkynyl, nitro, alkoxy, cyano, amino, sulfonic acid, haloalkyl, aryl, heteroaryl, and halogen; and R′ is alkyl or aryl.

2. The use of chromanone compounds according to claim 1 in the prevention and treatment of kiwi fruit bacterial canker, characterized in that: R is hydrogen, C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, nitro, halogen, C1-C6 alkoxy, cyano, amino, sulfonic acid, halogenated C1-C6 alkyl, C6-C 10 One or more of aryl or 5-10 membered heteroaryl.

3. The use of chromanone compounds according to claim 1 in the prevention and treatment of kiwi fruit bacterial canker, characterized in that: R is one of hydrogen, halogen, and C1-C6 alkyl; and R' is methyl or phenyl.

4. The use of chromanone compounds according to any one of claims 1 to 3 in the prevention and treatment of kiwi fruit bacterial canker, characterized in that: The structural formula of the chromanone compound is One of them.

5. A chromanone compound according to any one of claims 1 to 4, characterized in that: Its structural formula is One of them.

6. The chromanone compound according to claim 5, characterized in that: Its structural formula is One of them.

7. A method for preparing chromanone compounds as claimed in claim 6, characterized in that: Its One of the above-mentioned compounds and sodium methanesulfinate are used as raw materials, and sulfone substitution is carried out under acidic catalytic conditions to obtain the chromanone compound.

8. Use of the chromanone compound according to any one of claims 1 to 4 in the preparation of a product against kiwifruit bacterial canker.

9. A product for resisting kiwi fruit bacterial canker, characterized in that: Contains the chromanone compound as described in any one of claims 1 to 4.

10. Use of the product against kiwifruit bacterial canker as claimed in claim 9 in the prevention and treatment of kiwifruit bacterial canker.

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