A chromanone compound and application thereof in prevention and treatment of bacterial canker disease of kiwifruit

Abstract

The application discloses a chromanone compound and application of the chromanone compound in prevention and treatment of bacterial canker disease of kiwi fruit, and a structural formula of the chromanone compound is shown in the following formula: wherein R is one or more of hydrogen, alkyl, alkenyl, alkynyl, nitro, alkoxy, cyano, amino, sulfonic acid group, halogenated alkyl, aryl, heteroaryl and halogen; and R' is alkyl or aryl. A synthesis method provided by the application uses cheap and easily obtained 2-hydroxyacetophenone as a basic raw material to perform conventional chemical synthesis, and the reaction can be completed under mild conditions without metal catalysts. The synthesis method has the advantages of simple reaction system, short reaction time, high yield, and the like, and can greenly synthesize the chromanone compound; meanwhile, the chromanone compound has obvious prevention and treatment effect on bacterial canker disease of kiwi fruit.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pesticides, in particular to a chromanone compound and its application in the prevention and treatment of bacterial canker disease of kiwifruit. BACKGROUND

[0002] The pathogenic bacterium of bacterial canker disease of kiwifruit is Pseudomonas syringae pv. actinidiae, which has the characteristics of wide host range, strong pathogenicity, fast occurrence and difficult eradication. It can cause a large number of kiwifruit plant death in a short period of time, and has become a major limiting factor for the development of kiwifruit industry. The pathogenic bacterium mainly harms the new shoots, branches, leaves and flower buds of kiwifruit, and causes the withering and death of the plants, resulting in large-scale death of the plants and serious damage to the yield and quality of kiwifruit.

[0003] The existing prevention and control methods of kiwifruit canker disease mainly include cultivation management protection, cultivation of high-resistant varieties, biological control and chemical control and other measures. Unified prevention and control and comprehensive prevention and control can minimize the harm of bacterial canker disease of kiwifruit. Although there are various methods to prevent and control bacterial canker disease of kiwifruit, chemical agents are still a major control method. Therefore, it is of great significance to develop a safe and effective new pesticide with novel structure for the prevention and treatment of kiwifruit canker disease.

[0004] Chromanone compounds have various biological activities, including anti-inflammatory, antioxidant, antibacterial and the like. In particular, chromanone skeleton compounds have more applications in agricultural chemicals, which have attracted more attention in recent years. The Chinese patent application document with the publication number CN111943939A discloses a synthesis method of chromanone compounds and their agricultural biological activities. It provides a brand-new method, which comprises adding 2-(allyloxy)benzaldehyde and 2-hydroxyisoindoline-1,3-dione into a reactor respectively, under the action of a catalyst and a eutectic solvent, heating and reacting at 50-100℃ in a closed condition for 5-8 hours under air condition. After the reaction is completed, column chromatography separation is carried out to obtain chromanone compounds. The synthesized compounds can be applied alone or in combination in the prevention and treatment of Valsam a l i and C o l l e t o t ri c h u m gloeosporioides Penz. However, the disclosed chromanone compounds have complex structures, and have not been applied to the prevention and treatment of kiwifruit. It is still of great practical significance to further explore the simple synthesis of chromanone compounds with novel structure and the activity research in the prevention and treatment of bacterial canker disease of kiwifruit, and to develop candidate compounds with safety and high efficiency. SUMMARY

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

[0006] The present application solves the above technical problem by the following technical means:

[0007] The application of a chromanone compound in the prevention and treatment of bacterial canker of kiwifruit, 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 group, halogenated alkyl, aryl, heteroaryl, halogen; R' is alkyl or aryl.

[0008] Preferably, R is one or more of hydrogen, C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, nitro, halogen, C1-C6 alkoxy, cyano, amino, sulfonic acid group, halogenated C1-C6 alkyl, C6-C10 aryl or 5-10 membered heteroaryl. 10 Preferably, R is one or more of hydrogen, C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, nitro, halogen, C1-C6 alkoxy, cyano, amino, sulfonic acid group, halogenated C1-C6 alkyl, C6-C10 aryl or 5-10 membered heteroaryl.

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

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

[0011] Preferably, the structural formula of the chromanone compound is

[0012] The present application also provides a chromanone compound, the structural formula of which is Preferably, the structural formula of the chromanone compound is

[0013] Preferably, the structural formula of the chromanone compound is Preferably, the structural formula of the chromanone compound is

[0014] The present application also provides a preparation method of the chromanone compound, which uses one of as raw materials, and a sodium methylsulfinic acid as raw materials, and under acid catalysis, a sulfonyl substitution is performed to obtain the chromanone compound.

[0015] Preferably, an acid is used as a catalyst for catalysis, and the acid is a common protonic acid.

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

[0017] The present application also provides an application of the chromanone compound in the preparation of a product for resisting bacterial canker of kiwifruit.

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

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

[0020] Preferably, the product for resisting bacterial canker of kiwifruit has a concentration of the chromanone compound of 0.1-10 mg / mL.

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

[0022] In the present application, in the preparation process of the chromanone compound, first, under an air atmosphere, using an o-hydroxyacetophenone compound as a raw material and an amine salt as an additive, an enyl intermediate is obtained by heating reaction in a tetrahydrofuran solvent, and the enyl intermediate is subjected to 3-sulfone group substitution under the catalysis of an acid to obtain a chromanone product, and the synthesis route is as follows:

[0023]

[0024] In the present application, in the preparation process of the chromanone compound, first, under an air atmosphere, using an o-hydroxyacetophenone compound as a raw material and an amine salt as an additive, an enyl intermediate is obtained by heating reaction in a tetrahydrofuran solvent, and the enyl intermediate is subjected to 3-sulfone group substitution under the catalysis of an acid to obtain a chromanone product, and the synthesis route is as follows:

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

[0026] Preferably, the reaction temperature is 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 is a silica gel column, the eluent used for the intermediate 2 is petroleum ether: ethyl acetate with a volume ratio of 40:1, and the eluent used for the final product 3 is petroleum ether: ethyl acetate with a volume ratio of 5:1.

[0028] Compared with the prior art, the present application has the following advantages:

[0029] The synthesis method provided by the application uses cheap and easily available 2-hydroxyacetophenone as a basic raw material to perform conventional chemical synthesis, and the reaction can be completed under mild conditions without metal catalysts. The synthesis method has a simple reaction system, short reaction time, high yield, and can greenly synthesize chromanone compounds; meanwhile, the chromanone compounds have obvious prevention and treatment effect on kiwifruit bacterial canker disease bacteria. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 The nuclear magnetic hydrogen spectrum of compound 3a prepared in example 1 of the application is shown in the figure;

[0031] Figure 2 The nuclear magnetic carbon spectrum of compound 3a prepared in example 1 of the application is shown in the figure;

[0032] Figure 3 The nuclear magnetic hydrogen spectrum of compound 3b prepared in example 2 of the application is shown in the figure;

[0033] Figure 4 The nuclear magnetic carbon spectrum of compound 3b prepared in example 2 of the application is shown in the figure;

[0034] Figure 5 The nuclear magnetic hydrogen spectrum of compound 3c prepared in example 3 of the application is shown in the figure;

[0035] Figure 6 The nuclear magnetic carbon spectrum of compound 3c prepared in example 3 of the application is shown in the figure;

[0036] Figure 7 The nuclear magnetic hydrogen spectrum of compound 3d prepared in example 4 of the application is shown in the figure;

[0037] Figure 8 The nuclear magnetic carbon spectrum of compound 3d prepared in example 4 of the application is shown in the figure;

[0038] Figure 9 The nuclear magnetic hydrogen spectrum of compound 3e prepared in example 5 of the application is shown in the figure;

[0039] Figure 10 The nuclear magnetic carbon spectrum of compound 3e prepared in example 5 of the application is shown in the figure;

[0040] Figure 11 The figure is the antibacterial result diagram of compound 2b and compound 3b prepared in the example of the application after soaking in kiwifruit tissue culture seedling bacterial liquid;

[0041] Figure 12 The figure is the colony count of kiwifruit tissue culture seedling leaf after soaking in bacterial liquid treated by compound 2b prepared in the example of the application;

[0042] Figure 13The colony count of the leaves of the kiwi fruit tissue culture seedlings treated with compound 3b prepared in the embodiment of the present application after bacterial liquid immersion. DETAILED DESCRIPTION

[0043] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0044] The test materials and reagents used in the following embodiments, unless otherwise specified, can be obtained from commercial channels.

[0045] The specific techniques or conditions not specified in the embodiments 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 includes the following steps: diisopropylamine is stirred in a mixture of tert-butyl methyl ether at 0°C, and trifluoroacetic acid is added, wherein the molar ratio of diisopropylamine to trifluoroacetic acid is 1:1, the reaction mixture is stirred at 0°C for 10 minutes, and the excess solvent is removed by reduced pressure concentration to obtain pure white crystalline salt, which is diisopropylamine trifluoroacetic acid complex salt.

[0047] The intermediates and target products are separated and purified by column chromatography, and the stationary phase used in the column chromatography is a silica gel column. The eluent used for the intermediates (2a, 2b, 2d, 2e) is petroleum ether: ethyl acetate with a volume ratio of 40:1, and the eluent used for the target products (3a-e) is petroleum ether: ethyl acetate with 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 referred to the literature (Chem. Commun., 2010, 46, 1715-1717). In a 100 mL round-bottom flask, o-hydroxyacetophenone (1.0 mmol, 120 μL), diisopropylamine trifluoroacetate 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, the mixture was cooled to room temperature. The mixture was concentrated by a rotary evaporator and then purified by column chromatography to obtain a light yellow oil of chromanone compound 2a (107 mg, 67% yield). The nuclear magnetic data was consistent with the literature.

[0052] Compound 2a (0.67 mmol, 107 mg) was dissolved in 5.0 mL of ethanol solution. Sodium methylsulfinate (1.0 mmol, 104 mg) and p-toluenesulfonic acid monohydrate (0.54 mmol, 103 mg) were added. The mixture was stirred at 60 °C for 6 hours. After the reaction was completed, the mixture was cooled to room temperature. The mixture was concentrated by a rotary evaporator and then purified by column chromatography to obtain white solid 3a (134 mg, 83% yield). The structure of the compound was tested by nuclear magnetic spectrogram as shown in Figures 1-2 The specific results are as follows: 1 H NMR (600 MHz, CDCl3) δ 7.87 (d, J = 7.8 Hz, 1H), 7.51 (t, J = 7.2 Hz, 1H), 7.04 (t, J = 7.2 Hz, 1H), 7.00 (d, J = 8.4 Hz, 1H), 4.89 (dd, J = 10.8 Hz, J = 4.8 Hz, 1H), 4.33 (dd, J = 12.0 Hz, J = 10.8 Hz, 1H), 3.87 (dd, J = 14.4 Hz, J = 2.4 Hz, 1H), 3.52-3.54 (m, 1H), 3.04 (s, 3H), 2.92 (dd, J = 14.4 Hz, J = 8.4 Hz, 1H); 13 C{H}NMR (150 MHz, CDCl3) δ 190.5, 161.9, 136.8, 127.6, 122.0, 120.1, 118.2, 69.9, 50.6, 42.1, 41.0. The synthesized compound was analyzed by nuclear magnetic resonance to be the target compound 3a.

[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, the mixture was cooled to room temperature, concentrated by a rotary evaporator, and then purified by column chromatography to obtain the intermediate 2b (109 mg, 61% yield) as a light yellow oil.

[0057] Intermediate 2b (0.61 mmol, 109 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. The mixture was stirred at 60 °C for 6 hours, and then cooled to room temperature. The mixture was concentrated by a rotary evaporator and then purified by column chromatography to obtain compound 3b (124 mg, 79% yield) as a white solid. The structure of the compound was confirmed by nuclear magnetic resonance test spectrum as shown in Figures 3-4 1 H NMR (600 MHz, CDCl3) δ 7.54 (dd, J = 7.8 Hz, J = 3.0 Hz, 1H), 7.24-7.25 (m, 1H), 7.00 (dd, J = 9.0 Hz, J = 4.2 Hz, 1H), 4.91 (dd, J = 11.4 Hz, J = 5.4 Hz, 1H), 4.33 (dd, J = 12.0 Hz, J = 11.4 Hz, 1H), 3.86 (dd, J = 14.4 Hz, J = 3.6 Hz, 1H), 3.52-3.57 (m, 1H), 3.05 (s, 3H), 2.94 (dd, J = 14.4 Hz, J = 8.4 Hz, 1H); 13 C{H}NMR (150 MHz, CDCl3) δ 189.9, 158.4, 157.5 (d, J = 222.0 Hz), 124.5 (d, J = 24.0 Hz), 120.5 (d, J = 6.0 Hz), 120.0 (d, J = 7.5 Hz), 112.5 (d, J = 24 Hz), 70.1, 50.5, 42.2, 40.9. The synthesized compound was confirmed by nuclear magnetic analysis to be the target compound 3b.

[0058] Example 3

[0059] Synthesis method of compound 3c:

[0060]

[0061] ​Intermediate 2a (0.5 mmol, 80 mg) was dissolved in 5.0 mL of ethanol solution, sodium benzenesulfinate (0.75 mmol, 123 mg) and p-toluenesulfonic acid monohydrate (0.4 mmol, 76 mg) were added, and the mixture was stirred at 60 °C for 6 hours. After the reaction was completed, the mixture was cooled to room temperature, concentrated by a rotary evaporator, and then purified by column chromatography to obtain white solid 3c (50 mg, 33% yield). The structure of the compound was tested by nuclear magnetic resonance spectrum as shown in Figures 5-6 The data results are as follows: 1 H NMR (600 MHz, CDCl3) δ 7.97 (d, J = 7.8 Hz, 2H), 7.83 (d, J = 7.8 Hz, 1H), 7.69 (t, J = 7.2 Hz, 1H), 7.60 (t, J = 7.2 Hz, 2H), 7.50 (t, J = 7.2 Hz, 1H), 7.01 (dd, J = 17.4 Hz, J = 7.2 Hz, 2H), 5.00 (dd, J = 11.4 Hz, J = 5.4 Hz, 1H), 4.35 (dd, J = 11.4 Hz, J = 10.8 Hz, 1H), 3.98 (dd, J = 15.0 Hz, J = 3.6 Hz, 1H), 3.39-3.44 (m, 1H), 3.01 (dd, J = 15.0 Hz, J = 10.2 Hz, 1H); 13 C{H}NMR (150 MHz, CDCl3) δ 190.0, 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 compound synthesized by nuclear magnetic analysis was the target compound 3c.

[0062] Example 4

[0063] Synthesis method of compound 3d:

[0064]

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

[0066] Intermediate 2d (0.69 mmol, 120 mg) was dissolved in 5.0 mL of ethanol solution, sodium methanesulfinate (1.04 mmol, 108 mg) and p-toluenesulfonic acid monohydrate (0.55 mmol, 105 mg) were added, and the mixture was stirred at 60 °C for 6 hours. After the reaction was completed, the mixture was cooled to room temperature, concentrated by a rotary evaporator, and then purified by column chromatography to obtain white solid 3d (142 mg, 81% yield). The structure of the compound was tested by nuclear magnetic resonance spectrum as shown in Figures 7-8 The data results are as follows: 1 H NMR (600 MHz, CDC13) δ 7.67 (s, 1H), 7.33 (d, J = 8.4 Hz, 1H), 6.91 (d, J = 8.4 Hz, 1H), 4.86 (dd, J = 10.8 Hz, J = 5.4 Hz, 1H), 4.30 (dd, J = 11.4 Hz, J = 10.8 Hz, 1H), 3.87 (dd, J = 14.4 Hz, J = 2.4 Hz, 1H), 3.49-3.53 (m, 1H), 3.04 (s, 3H), 2.92 (dd, J = 14.4 Hz, J = 8.4 Hz, 1H), 2.31 (s, 3H); 13 C{H}NMR (150 MHz, CDC13) δ 190.6, 159.8, 137.8, 131.4, 130.0, 119.5, 117.8, 69.7, 50.6, 41.9, 40.9, 20.3. The compound synthesized by nuclear magnetic analysis was the target compound 3d.

[0067] Example 5

[0068] Synthesis method of compound 3e:

[0069]

[0070] Referring to the synthesis of compound 2a, 1-(3-hydroxy-5,6,7,8-tetrahydro-2- naphthalenyl)-ethanone (1.0 mmol, 190 mg), diisopropylamine trifluoroacetate 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, the mixture was cooled to room temperature, concentrated by a rotary evaporator, and then purified by column chromatography to obtain yellowish oil intermediate 2e (131 mg, 61% yield).

[0071] Intermediate 2e (0.61 mmol, 131 mg) was dissolved in 5.0 mL of ethanol solution, sodium methanesulfinate (0.92 mmol, 96 mg) and p-toluenesulfonic acid monohydrate (0.49 mmol, 93 mg) were added, stirred at 60 °C for 6 h, after the reaction was completed, cooled to room temperature, the mixture was concentrated by rotary evaporator and then purified by column chromatography to obtain white solid 3e (138 mg, 77% yield), the structure of the compound was tested by nuclear magnetic resonance spectrum as shown in Figures 9-10 The data results are as follows: 1 H NMR (600 MHz, CDC13) δ 7.56 (s, 1H), 6.69 (s, 1H), 4.82 (dd, J = 10.8 Hz, J = 5.4 Hz, 1H), 4.26 (dd, J = 11.4 Hz, J = 10.8 Hz, 1H), 3.85 (dd, J = 14.4 Hz, J = 3.0 Hz, 1H), 3.44-3.48 (m, 1H), 3.03 (s, 3H), 2.91 (dd, J = 14.4 Hz, J = 8.4 Hz, 1H), 2.74 (d, J = 29.4 Hz, 4H), 1.76-1.77 (m, 4H); 13 C{H}NMR (150 MHz, CDC13) δ 190.5, 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 compound synthesized by nuclear magnetic analysis is the target compound 3e.

[0072] Example 6

[0073] Bacteriostatic activity test

[0074] A series of target compounds synthesized were detected for control effect on Pseudomonas syringae pv. Actinidiae by filter paper disc diffusion method. Since the synthesized chromanone compounds have good stability at room temperature and are not soluble in water, the compounds were dissolved in acetone to prepare a concentration of 6.0 mg / mL, and acetone and gentamicin sulfate were used as negative and positive controls, respectively. The bacteria were filtered and sterilized by using sterile organic phase microporous filter membrane with a diameter of 0.2 μm, and the filter paper was punched into several filter paper pieces by using a single-hole puncher with a diameter of 6 mm. Pseudomonas syringae pv. Actinidiae was inoculated into LB solid medium by streaking method and incubated in a 37 °C constant temperature incubator for 24 h for activation. Then 5 mL of LB liquid was taken in a 10.0 mL shaking tube, and a small amount of bacteria was taken with a inoculation loop and mixed in the LB liquid shaking tube, which was incubated at 37 °C, 180 r / min in a shaking bed for 8-10 h. The concentration of the bacterial suspension was adjusted to about 10 6For CFU / mL, pipette 100 μL of bacterial suspension and add it to 100 mL of Luria-Bertani (LB) medium at 50-60℃, mix thoroughly, and pour onto agar plates. After the LB plates containing bacteria solidify, place sterile filter paper on the plates, and add 5 μL of the target compound solution, gentamicin sulfate, or acetone to each filter paper. Finally, incubate the plates at 37℃ for 24-36 h. The diameter of the inhibition zone (IZD, in mm) is measured using the cross-hatching method to assess antibacterial activity. Three replicates are used for 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 *Actinidia kiwifruit* bacterial canker pathogen.

[0076] Table 1

[0077]

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

[0079] As shown in Table 1 above, the compounds of the present invention have a good inhibitory effect on bacterial canker pathogens of kiwifruit.

[0080] Compounds 2b and 3b, which showed good antibacterial effects, were selected for an experiment using the immersion method with mycelial solution in kiwifruit tissue culture seedlings.

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

[0082] Experimental methods and procedures:

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

[0084] (2) Drug concentration setting: Dissolve the two compounds in acetone to prepare concentrations of 3 mg / mL, 600 μg / mL and 300 μg / mL respectively;

[0085] (3) Medium setting: In the clean bench, seven groups of 100 mL subculture medium were weighed, one group of ordinary subculture medium (without adding any medicament), and the other six groups were added with 100 μL intermediate compound 2b (3 mg / mL), 100 μL intermediate compound 2b (600 μg / mL), 100 μL intermediate compound 2b (300 μg / mL), 100 μL final product compound 3b (3 mg / mL), 100 μL final product compound 3b (600 μg / mL), and 100 μL final product compound 3b (300 μg / mL) respectively, and each group was poured into 3 sterile tissue culture subculture bottles and naturally cooled and solidified;

[0086] (4) Tissue culture seedling subculture: In the clean bench, healthy and disease-free 'Red Yang' tissue culture seedlings were selected using high-temperature sterilized tweezers (286°C, 20 min, natural cooling) and were inserted obliquely into the medium;

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

[0088] (6) Tissue culture seedling inoculation: The kiwifruit canker strain JF8 stored at -80°C was taken out, thawed at room temperature, and then inoculated on LB medium for strain activation. After 2 d of plate culture, a single colony was picked and added to a 2 mL centrifuge tube with LB liquid medium, and then cultured at 28°C with 200 r / min shaking for 12 h. The activated bacterial liquid was centrifuged at 6000 rpm for 5 min, and the supernatant was removed and the bacterial body was collected. 1 mL of pre-sterilized PBS was used to resuspend the bacterial body, and the precipitate was gently dispersed to completely suspend the bacterial body. The OD600nm of the bacterial liquid was measured to be 0.2. In the clean bench, the tissue culture seedlings cultured for 45 d were opened, and the OD-adjusted bacterial liquid was added to ensure that the whole seedling was soaked in the bacterial liquid. After 5 min, the bacterial liquid was poured out. The seedlings were cultured at 25°C with 16 h light and 8 h dark for 7 d, and the experimental results of the tissue culture seedlings were as follows Figure 11 As shown in the table, Figure 11 It can be seen that the antibacterial activity of compound 2b at 600 μg / mL and compound 3b at 3 mg / mL in the kiwifruit tissue culture seedlings is the best.

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

[0090] One piece of the diseased leaf after inoculation of the WT strain (without adding any medicament) and the different medicament-treated strains was taken, 1 mL of sterile PBS solution was added, and the leaf was ground to a homogenate state with a mortar and then transferred to a 1.5 mL centrifuge tube to obtain a grinding liquid;

[0091] The grinding liquid was gradiently diluted with PBS solution to a bacterial concentration of 10 -7 (Sequentially diluted from 10 -1 , 10 -2、10 -3 、10 -4 、10 -5 、10 -6 、10 -7 ), during which the liquid is fully mixed to avoid the bacteria adhering to the bottom of the centrifugal tube;

[0092] 5 μL of the sample solution of each concentration gradient was taken in the super-clean workbench, and the sample liquid was slowly spotted on the LB culture plate, and then the culture plate was placed in a 28℃ incubator for 2 days after the surface was dried. The culture plate was taken out and photographed for counting after 2 days of culture. The results are shown in Figure 12 and 13 , wherein the bacterial concentration from left to right is 10 -1 , 10 -2 , 10 -3 , 10 -4 , 10 -5 , 10 -6 , 10 -7 , and it can be seen from Figure 12 and 13 that the number of bacteria of kiwifruit canker disease in the leaf of the kiwifruit tissue culture seedling is the least when the concentration of compound 2b is 600 μg / mL and the concentration of compound 3b is 3 mg / mL, that is, the antibacterial activity is the best when the concentration of compound 2b is 600 μg / mL and the concentration of compound 3b is 3 mg / mL.

[0093] The above examples are only used to illustrate the technical solutions of the present application, but not limit the same; although the present application has been described in detail with reference to the foregoing examples, it should be understood by those skilled in the art that the technical solutions recorded in the foregoing examples can be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. The use of a chromanone compound in the prevention and treatment of bacterial canker disease of kiwifruit, characterized in that: The structural formula of the thiochromanone compound is or wherein R is one of hydrogen, halogen, C1-C6 alkyl; R' is methyl or phenyl.

2. The use of a chromanone compound in the prevention and treatment of bacterial canker disease of kiwifruit, characterized in that: The structural formula of the colorant ketone compound is 、 、 、 、 、 、 、 、 one of the following.

3. A chromanone compound, characterized by: The structural formula is , , , one of the following.

4. The chromanone compound according to claim 3, characterized by: The structural formula is , , one of the following.

5. A method for preparing the chromone compound as described in claim 4, characterized in that: It is prepared from one of the following compounds: , , under acidic catalytic conditions by substitution of the sulfone group with sodium methylsulfinate.

6. The application of a chromone compound in the preparation of a product resistant to bacterial canker in kiwifruit, wherein the structural formula of the chromone compound is as follows: or ,in, R is one of hydrogen, halogen, C1-C6 alkyl; said R' is methyl or phenyl.

7. A product for combating Pseudomonas syringae pv. actinidiae, characterized in that: The chromanone compound has a structure as shown in one of the following formulas: , , , .

8. Use of a product according to claim 7 against Pseudomonas syringae pv. actinidiae in the control of bacterial canker of kiwifruit.

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