Bactericidal composition and application thereof in preventing and treating crop diseases caused by fusarium

Abstract

The invention discloses a bactericidal composition and application thereof in preventing and treating crop diseases caused by fusarium, the active ingredients of the bactericidal composition comprise luliconazole and an ergosterol biosynthesis inhibitor, and the mass ratio of the luliconazole to the ergosterol biosynthesis inhibitor is (4: 1)-(1: 4). It is found that the luliconazole compound can significantly improve the bacteriostatic effect of ergosterol biosynthesis inhibitors such as tebuconazole, prothioconazole and prochloraz on fusarium, and can be used for preventing and treating crop diseases caused by fusarium.

Description

Technical Field

[0001] The present application relates to the field of crop disease prevention and control, and specifically to a fungicide composition and its application in preventing and controlling crop diseases caused by Fusarium. Background Art

[0002] Fusarium, as a type of fungus widely distributed around the world, can cause a variety of plant diseases, including but not limited to root rot, stem base rot, blossom rot and ear rot, which often lead to serious reductions in crop yield and quality. In recent years, due to climate change and the long-term return of large amounts of straw to the fields, Fusarium diseases of crops such as wheat fusarium rust and corn ear rot have shown a clear trend of increasing incidence. Fusarium diseases not only cause serious yield losses, but the pathogens can also produce fungal toxins such as deoxynivalenol (DON), zearalenone (ZEA), and fumonisin (FUM), which pose a serious threat to human and animal health and have attracted great attention from the government and society.

[0003] Currently, due to the lack of highly resistant crop varieties, chemical control is still one of the main measures for the prevention and control of crop Fusarium diseases. In my country, sterol biosynthesis inhibitors (SBIs) such as tebuconazole, prothioconazole, and prochloraz are widely registered for the prevention and control of Fusarium diseases of various crops, such as fusarium head blight, root rot, and rice seedling blight. However, long-term use of agents can lead to resistance of pathogens to such agents. Therefore, it is particularly important to explore highly effective compounds and develop new combinations of agents for the prevention and control of Fusarium diseases.

[0004] Tebuconazole: Its chemical name is (RS)-1-p-chlorophenyl-4,4-dimethyl-3-(1H-1,2,4-triazol-1-ylmethyl)pentan-3-ol. It is a sterol demethylation inhibitor that inhibits the synthesis of ergosterol in pathogens and can be used to prevent and control various crop diseases such as ergosterol and root rot.

[0005] Prothioconazole: Its chemical name is (RS)-2-[2-(1-chlorocyclopropyl)-3-(2,4-dichlorophenyl)-2-hydroxypropyl]-1,2-dihydro-3H-1,2,4-triazole-3-thione. It is a sterol demethylation inhibitor (DMI) with broad-spectrum antifungal activity. It is widely used to control various diseases of crops such as wheat, corn, and soybeans, such as white head mold, rust, ear rot, and smut.

[0006] Prochloraz: Its chemical name is N-propyl-N-[2-(2,4,6-trichlorophenyl)-2-hydroxyethyl]imidazole-1-carboxamide. It is a sterol demethylation inhibitor (DMI) with broad-spectrum antifungal activity. It is suitable for the prevention and control of various crop diseases, and is commonly used to prevent and control various diseases such as rice seedling blight, wheat ergot, and powdery mildew.

[0007] Luliconazole: (±)-1-[(2R,3S)-2-[(4-chlorophenyl)thio]methyl]-3-[(4-fluorophenyl)oxy]propyl]-1H-imidazole. Its synthesis process is three steps: 1) (S)-2-chloro-1-(2,4-dichlorophenyl)ethanol reacts with methylsulfonyl chloride in the presence of triethanolamine (TEA) to generate the corresponding (S)-2,4-dichloro-α-(chloromethyl)benzyl alcohol methanesulfonate; 2) imidazole-1-yl acetonitrile reacts with carbon disulfide in the presence of sodium hydroxide and DMSO to obtain a reaction solution of 2-(1H-imidazole-1-yl)-3,3-dimercaptoacrylonitrile sodium salt. 3) Dissolve (S)-2,4-dichloro-α-(chloromethyl)benzyl alcohol methanesulfonate in DMSO, add dropwise 2-(1H-imidazole-1-yl)-3,3-dimercaptoacrylonitrile sodium salt reaction solution, stir and react to obtain luliconazole. The compound structural formula is shown below:

[0008] Summary of the invention

[0009] The present application discovered that the compound luliconazole can significantly increase the antibacterial effect of ergosterol synthesis inhibitors such as tebuconazole, prothioconazole, and prochloraz on Fusarium, and can be used to prevent and control crop diseases caused by Fusarium. Based on this, a fungicide composition and its application in preventing and controlling crop diseases caused by Fusarium are provided.

[0010] A fungicidal composition, wherein the active ingredients are composed of luliconazole and an ergosterol biosynthesis inhibitor, wherein the mass ratio of luliconazole to the ergosterol biosynthesis inhibitor is 4:1 to 1:4; the structural formula of luliconazole is as shown in formula (I); and the ergosterol biosynthesis inhibitor is at least one of tebuconazole, prothioconazole and prochloraz;

[0011]

[0012] Optionally, the mass ratio of luliconazole to ergosterol biosynthesis inhibitor is 3:1 to 1:2; more preferably 2:1 to 1:2.

[0013] Optionally, the mass ratio of luliconazole to ergosterol biosynthesis inhibitor is 1: 1. Experimental verification shows that the 1: 1 composition has a significant synergistic effect on wheat fusarium head blight, corn ear rot, and rice seedling pathogen.

[0014] The fungicide composition of the present application, in addition to the active ingredients, may also contain other conventional agents such as carriers and adjuvants commonly used in pesticides as required.

[0015] The present application also provides an application of the fungicide composition in preventing and controlling crop diseases caused by Fusarium.

[0016] The present application also provides a use of the fungicidal composition in the preparation of a fungal inhibitor for inhibiting Fusarium.

[0017] Optionally, the Fusarium is at least one of Fusarium graminearum complex, Fusarium fujikuroi complex and Fusarium verticillioides.

[0018] Optionally, the crop disease is wheat fusarium rust, rice seedling rot or corn ear rot.

[0019] Among them, Fusarium graminearum can cause wheat fusarium fusarium, so it is also called wheat fusarium fusarium; Fusarium verticillioides can cause corn ear rot, so it is also called corn ear rot; Fusarium fujikuroi can cause rice seedling rot, so it is also called rice seedling rot.

[0020] In the application of preventing and treating wheat fusarium graminearum caused by wheat fusarium graminearum, preferably, the active ingredients of the fungal composition are compounded with luliconazole and tebuconazole in a mass ratio of 1:1 to 1:2. Under this compound combination, a significant synergistic effect is shown on wheat fusarium graminearum.

[0021] In the application of preventing and controlling corn ear rot caused by Fusarium verticillioides, one preferred method is that the active ingredients of the fungal composition are compounded by luliconazole and tebuconazole at a mass ratio of 2:1 to 1:2; another preferred method is that the active ingredients of the fungal composition are compounded by luliconazole and prothioconazole at a mass ratio of 1:1. Under this compound combination, a significant synergistic effect is shown on corn ear rot fungi.

[0022] In the application of preventing and controlling rice seedling rot caused by Fusarium fujikuroi, preferably, the active ingredients of the fungal composition are compounded with luliconazole and prochloraz in a mass ratio of 1:1 to 1:3. Under this compound combination, a significant synergistic effect is shown on rice seedling rot fungi.

[0023] The present application also provides a method for preventing and treating wheat fusarium graminearum caused by luliconazole. Luliconazole has a strong antibacterial effect on wheat fusarium graminearum. 50 The value is only 0.00833, which is about one-fiftieth of that of tebuconazole.

[0024] The present application also provides a method for preventing and controlling crop diseases caused by Fusarium, wherein the bactericidal composition is applied to the diseased crops. Optionally, the application can be carried out in the form of pesticides. The crop diseases are wheat head blight, rice seedling rot or corn ear rot.

[0025] The fungicide composition of the present invention has excellent preventive effect on crop diseases caused by Fusarium. Compared with the prior art, the fungicide composition of the present invention has at least one of the following advantages:

[0026] (1) Luliconazole has a synergistic effect when combined with triazole agents, which can significantly improve the fungicidal activity and control effect.

[0027] (2) Compared with existing triazole fungicides, luliconazole has a strong antibacterial effect against Fusarium wilt. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is the molecular docking diagram of luliconazole and the transcription factor SR protein of wheat fusarium rust (the yellow, green and blue parts in the figure are luliconazole).

[0029] Figure 2 This is a diagram showing the experimental results of a microthermophoresis experiment proving that luliconazole directly binds to the transcription factor FgSR of wheat fusarium.

[0030] Figure 3 This is a graph showing the results of the efficacy test of luliconazole and tebuconazole combined against wheat fusarium rust. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0033] Screening and identification of luliconazole, a compound with strong antibacterial activity against Fusarium:

[0034] In order to screen more efficient compounds that have synergistic effects on existing triazole fungicides, an antibacterial compound library containing 394 compounds was screened against Gibberella fusca. The results showed that the compound luliconazole had strong antibacterial activity against Gibberella fusca. The EC of the compound on the mycelial growth of Gibberella fusca was 1.34 %. 50 The concentration of luliconazole in the ergosterol synthesis inhibitor is 0.00833 μm, which is significantly better than the existing ergosterol synthesis inhibitors such as tebuconazole, prothioconazole, and prochloraz. Molecular docking analysis showed that luliconazole can effectively bind to the transcription factor SR ( Figure 1 ). Microscale thermophoresis (MST) test further confirmed that luliconazole has a strong binding ability with the SR protein of wheat fusarium ( Figure 2 ), indicating that luliconazole can directly act on the transcription factor SR of Fusarium graminearum. FgSR (the transcription factor SR of Fusarium graminearum) is the main regulatory factor for the synthesis of sterols in the pathogen. The sterol content in its deletion mutant is reduced, and the sensitivity to triazole fungicides such as tebuconazole is significantly increased. Therefore, luliconazole has a significant synergistic effect on triazole agents such as tebuconazole by acting on the transcription factor SR of Fusarium.

[0035] The following specific examples illustrate the activity determination of luliconazole in combination with ergosterol synthesis inhibitors such as tebuconazole, prothioconazole, and prochloraz:

[0036] Example 1 Indoor toxicity determination of luliconazole and tebuconazole against wheat fusarium

[0037] Test object: Wheat fusarium (Fusarium graminearum) isolated from the field. The test strain was preserved in this laboratory.

[0038] Test method: Refer to the hyphae growth rate method of "Agricultural Industry Standard of the People's Republic of China NY / T 1156.2-2006". Each agent was treated with 5 doses according to the effective ingredient content. The above wheat fusarium pathogen was inoculated on the PDA medium. When the colony grew to 2 / 3 of the culture dish, a 5mm diameter puncher was used to punch the colony edge into a block. The block was moved to the center of the pre-prepared drug-containing PDA medium plate with an inoculation needle, and then placed in a 25℃ incubator for 2 days. The diameter of each treated colony was measured with a caliper using the cross method to calculate the corrected inhibition percentage; and then the EC of each agent was calculated using the linear regression analysis between the probability value of the inhibition rate and the logarithm of the series concentration. 50 Each treatment was repeated 3 times.

[0039] Luliconazole was set as the standard drug and the co-toxicity coefficient (CTC) was calculated according to the following formula.

[0040]

[0041] Theoretical Toxicity Index (TTI) = Standard Agent Toxicity Index × Percentage of Standard Agent in Mixed Combination

[0042] +Toxicity index of the test agent × the percentage of the test agent in the mixed combination

[0043] Co-toxicity coefficient (CTC) = (ATI / TTI) × 100%

[0044] A CTC value of less than 80 indicates that the drug combination has an antagonistic effect; between 80-120, it indicates an additive effect; and greater than 120, it indicates a synergistic effect.

[0045] Table 1. Results of indoor toxicity test of luliconazole and tebuconazole against wheat fusarium

[0046]

[0047] As can be seen from Table 1, luliconazole has a strong antibacterial effect on Fusarium graminearum. 50 The value is only 0.00833, which is about one-fiftieth of that of tebuconazole; the combination of luliconazole and tebuconazole in a ratio of 1:1 to 1:2 showed a significant synergistic effect on wheat fusarium.

[0048] Example 2 Determination of the efficacy of luliconazole and tebuconazole combination against wheat scab

[0049] Experimental subjects: Wheat fusarium graminearum and Jimai 22 isolated from the field and preserved in our laboratory.

[0050] Select healthy and uniform wheat seeds, soak them in 70% ethanol for 30 seconds for disinfection, and then rinse them with distilled water 2-3 times. Then place the wheat on absorbent paper and keep it moist for 4 days. Then inoculate the fusarium spores on the coleoptile of wheat, place them horizontally, keep them moist for 3 days, and take pictures. Then measure the length of the lesions on the coleoptile and calculate the control effect of the agent. The results are as follows: Figure 3 shown.

[0051] Depend on Figure 3 It can be seen that compared with tebuconazole, luliconazole has a better inhibitory effect on the disease caused by Fusarium fusiformis on wheat coleoptiles. Tebuconazole and luliconazole cannot completely inhibit the lesions at a concentration of 50 μg / mL, but luliconazole and tebuconazole are mixed in a 1:1 ratio and a concentration of 50 μg / mL can completely inhibit the occurrence of lesions, indicating that the compound agent has a synergistic effect on disease control.

[0052] Example 3 Indoor toxicity determination of luliconazole and tebuconazole against corn ear rot pathogen

[0053] Test object: corn ear rot pathogen (Fusarium verticillioides) isolated in the field, the test strain is preserved by this laboratory. The bioassay method is as in Example 1.

[0054] Table 2. Results of indoor toxicity test of luliconazole and tebuconazole combination against corn ear rot

[0055]

[0056] From the results in Table 2, it can be seen that luliconazole has a good inhibitory effect on corn ear rot fungus. 50 It is only 0.03743 μM, and the combination of luliconazole and tebuconazole in a ratio of 2:1 to 1:2 has a significant synergistic effect, which can significantly improve the antibacterial effect of the agent on corn ear rot fungi.

[0057] Example 4 Indoor toxicity determination of luliconazole and prothioconazole against corn ear rot pathogen

[0058] Test object: corn ear rot pathogen (Fusarium verticillioides) isolated in the field, the test strain is preserved by this laboratory. The bioassay method is as in Example 1.

[0059] Table 3. Results of indoor toxicity test of luliconazole and prothioconazole combination against corn ear rot

[0060]

[0061] It can be seen from the results in Table 3 that luliconazole has a good inhibitory effect on corn ear rot fungi, and the 1:1 combination of luliconazole and prothioconazole has a synergistic effect, which can significantly improve the inhibitory effect of the agent on corn ear rot fungi.

[0062] Example 5 Indoor toxicity determination of luliconazole and prochloraz against rice bakanae pathogen

[0063] Test object: Rice seedling pathogen (Fusarium fujikuroi) isolated in the field, the test strain is preserved in this laboratory. The bioassay method is as in Example 1.

[0064] Table 4. Results of indoor toxicity test of luliconazole and prochloraz against rice seedling pathogen

[0065]

[0066] From the results in Table 4, it can be seen that luliconazole has a good inhibitory effect on the mycelial growth of rice seedling pathogen. 50 The value of luliconazole to rice seedling pathogen is 0.03593 μM. The combination of luliconazole and prochloraz in the ratio of 1:1 to 1:3 has a synergistic effect and can significantly improve the antibacterial effect of the agent on rice seedling pathogen.

[0067] In summary, the results of the indoor bioassay test show that luliconazole has a highly effective inhibitory activity against Fusarium, and the 1:1 composition of luliconazole and triazole fungicides in the present invention (the most preferred combination) has a significant synergistic effect on wheat fusarium, corn ear rot, and rice seedling rot, and has excellent antibacterial and disease prevention effects on crop Fusarium diseases.

[0068] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A bactericidal composition, characterized in that: The active ingredients are composed of luliconazole and an ergosterol biosynthesis inhibitor, wherein the mass ratio of luliconazole to the ergosterol biosynthesis inhibitor is 4:1 to 1:4; the structural formula of luliconazole is as shown in formula (I); the ergosterol biosynthesis inhibitor is at least one of tebuconazole, prothioconazole and prochloraz; 2. Use of the fungicidal composition as claimed in claim 1 in preventing and controlling crop diseases caused by Fusarium.

3. The use according to claim 2, characterized in that: The Fusarium is at least one of Fusarium graminearum complex, Fusarium fujikuroi complex and Fusarium verticillioides.

4. The use according to claim 2, characterized in that: The crop diseases are wheat scab, rice seedling rot or corn ear rot.

5. The use according to claim 2, characterized in that: The crop disease is wheat fusarium fusarium caused by Fusarium graminearum, the ergosterol biosynthesis inhibitor is tebuconazole, and the mass ratio of luliconazole to tebuconazole is 1:1 to 1:

2.

6. The use according to claim 2, characterized in that: The crop disease is corn ear rot caused by Fusarium verticillioides, the ergosterol biosynthesis inhibitor is tebuconazole or prothioconazole, the mass ratio of luliconazole to tebuconazole is 2:1 to 1:2, and the mass ratio of luliconazole to prothioconazole is 1:

1.

7. The use according to claim 2, characterized in that: The crop disease is rice seedling rot caused by Fusarium fujikuroi, the ergosterol biosynthesis inhibitor is prochloraz, and the mass ratio of luliconazole to prochloraz is 1:1 to 1:

3.

8. Use of the bactericidal composition according to claim 1 in the preparation of a fungal inhibitor for inhibiting fungi from Fusarium, wherein the Fusarium is at least one of Fusarium graminearum complex, Fusarium fujikuroi complex and Fusarium verticillioides.

9. Use of luliconazole in the prevention and treatment of wheat fusarium fusarium caused by Fusarium graminearum.

10. A method for preventing and controlling crop diseases caused by Fusarium, characterized in that: The fungicidal composition according to claim 1 is applied to diseased crops.

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