Application of a carbazole compound in preventing and controlling plant root-knot nematodes

Abstract

The present invention discloses the application of a carbazole compound in controlling plant root-knot nematodes. The carbazole compound is 1-(9H-carbazol-9-yl)-2-((1-methyl-1H-tetrazol-5-yl)thio)propane-1,1. The present invention discovers for the first time that 1-(9 H -carbazol-9-yl)-2-((1-methyl-1 H -tetrazol-5-yl)thio)propane-1,1 and its agriculturally acceptable salts have strong toxicicidal activity against root-knot nematodes and no toxicicidal activity against Caenorhabditis elegans, a non-plant pathogenic nematode, and have the characteristics of high efficiency and low toxicity, providing a new leading compound for the research and development of pesticides against root-knot nematodes.

Description

Technical Field

[0001] The present invention belongs to the technical field of agricultural pest control, and particularly relates to the application of a carbazole compound in controlling plant root-knot nematodes. Background Art

[0002] Plant parasitic nematodes, especially root-knot nematodes, have become a major threat to global agricultural production and ecological environment. Root-knot nematodes, which are obligate parasites on the roots of plants, are recognized as the invisible killers in the global plant kingdom due to their strong destructive power. Root-knot nematodes parasitize on the roots of plants, gradually weakening the plants' ability to absorb nutrients and water in the soil. This process not only leads to slow plant growth and withered yellow leaves, but may even directly cause the plants to wither and die in severe cases, bringing a devastating disaster to agricultural production and significantly reducing the yield and quality of crops. Once the crops are infected by root-knot nematodes, other diseases will take advantage of the situation and further exacerbate the damage to the crops, forming a vicious cycle. The concealment and complexity of root-knot nematode diseases make their prevention and control extremely difficult, like groping in the fog. Traditional chemical nematicides were once the main means of controlling root-knot nematodes. However, their high toxicity, potential carcinogenic risks and serious environmental pollution have been banned and restricted. Therefore, the development of highly efficient and low-toxic pesticides against root-knot nematodes is a major national demand. Therefore, the current research focus has shifted to in-depth exploration of the biological characteristics, infection mechanisms and drug resistance mechanisms of root-knot nematodes, and a series of highly efficient and low-toxic nematocidal compounds have been developed on this basis. These new compounds should not only have a powerful insecticidal effect, but also be environmentally friendly and safe for humans and animals to meet the requirements of modern agriculture for green and sustainable development. Based on this, creating new pesticides will provide a powerful weapon for controlling root-knot nematode diseases and ensuring the stability of global agricultural production and the health of the ecological environment. Carbazole compounds have been applied in the preparation of drugs or health foods for treating metabolic diseases and their complications, but there is no literature report on their application in controlling root-knot nematodes.

[0003] The present invention aims to provide the application of a carbazole compound in controlling plant root-knot nematodes. Summary of the Invention

[0004] The purpose of the present invention is to provide the application of a carbazole compound in controlling plant root-knot nematodes.

[0005] The purpose of the present invention is achieved as follows: the application of the carbazole compound 1-(9H-carbazol-9-yl)-2-((1-methyl-1H-tetrazol-5-yl)thio)propane-1-one and / or its agriculturally acceptable salts in controlling plant root-knot nematodes, and the structural formula of the carbazole compound 1-(9H-carbazol-9-yl)-2-((1-methyl-1H-tetrazol-5-yl)thio)propane-1-one is shown in Formula I:

[0006]

[0007] I.

[0008] The present invention first discovered that 1-(9 H -carbazol-9-yl)-2-((1-methyl-1 H -tetrazol-5-yl)thio)propane-1-1 and its agrochemically acceptable salts have strong toxicicidal activity against root-knot nematodes and no toxicicidal activity against Caenorhabditis elegans, a non-plant pathogenic nematode (its median lethal concentration LC50 for Meloidogyne incognita at 24 hours is 10.94 μg / ml, and at 48 hours is 10.71 μg / ml. The median lethal concentration LC50 for Meloidogyne javanica at 24 hours is 14.46 μg / ml, and at 48 hours for Meloidogyne enterolobii is 14.12 μg / ml. The median lethal concentration LC50 for Meloidogyne enterolobii at 24 hours is 14.24 μg / ml, and at 48 hours for Meloidogyne enterolobii is 13.59 μg / ml.), with the characteristics of high efficiency and low toxicity, providing a new lead compound for the research and development of pesticides against root-knot nematodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is the structural formula of the compound 1-(9H-carbazol-9-yl)-2-((1-methyl-1H-tetrazol-5-yl)thio)propane-1-1 of the present invention;

[0010] Figure 2 is the calculation result of the toxicity determination of the compound 1-(9H-carbazol-9-yl)-2-((1-methyl-1H-tetrazol-5-yl)thio)propane-1-1 in Example 1 against Meloidogyne incognita;

[0011] Figure 3 is the calculation result of the toxicity determination of 1-(9H-carbazol-9-yl)-2-((1-methyl-1H-tetrazol-5-yl)thio)propane-1-1 in Example 1 against Meloidogyne javanica;

[0012] Figure 4 is the calculation result of the toxicity determination of 1-(9H-carbazol-9-yl)-2-((1-methyl-1H-tetrazol-5-yl)thio)propane-1-1 in Example 1 against Meloidogyne enterolobii;

[0013] Figure 51H NMR spectrum of the compound 1-(9H-carbazol-9-yl)-2-((1-methyl-1H-tetrazol-5-yl)thio)propane-1-1 of the present invention. Detailed implementation mode

[0014] The present invention will be further described in detail below in conjunction with embodiments, but the present invention is not limited in any way. Any transformation or improvement based on the teachings of the present invention falls within the protection scope of the present invention.

[0015] The present invention provides the application of 1-(9H-carbazol-9-yl)-2-((1-methyl-1H-tetrazol-5-yl)thio)propane-1-1 and / or its agriculturally acceptable salts in controlling plant root-knot nematodes. The structural formula of the compound 1-(9H-carbazol-9-yl)-2-((1-methyl-1H-tetrazol-5-yl)thio)propane-1-1 is as Figure 1 shown. This compound is derived from the drug-like diversity compound library 50K Diversity Library containing 50,000 compounds developed by MCE (MedChemExpress). Its CatalogNumber is HY-L901 and Library ID is HY-LD-000004591. More than 90% of the compounds in this compound library are new compounds. The compound of the present invention is a new compound with CatalogNumber HY-Q05753, no CAS Number, a relative molecular mass of 337.40, and mass-to-charge ratios m / z of 337.10 (100.0%), 338.10 (18.4%), and 339.10 (4.5%).

[0016] The root-knot nematodes are Meloidogyne incognita, Meloidogyne javanica or Meloidogyne enterolobii.

[0017] The present invention also provides an insecticide for controlling plant root-knot nematodes, and the insecticide uses 1-(9H-carbazol-9-yl)-2-((1-methyl-1H-tetrazol-5-yl)thio)propane-1-1 and / or its agriculturally acceptable salts as the main active ingredient or one of the active ingredients.

[0018] The concentration of 1-(9H-carbazol-9-yl)-2-((1-methyl-1H-tetrazol-5-yl)thio)propane-1-1 in the insecticide is ≥5 μg / ml.

[0019] The dosage form of the insecticide is aqueous solution, aqueous emulsion, wettable powder, soluble powder, soluble granule, suspension, tablet or effervescent granule.

[0020] The solvent of the aqueous solution or aqueous emulsion is an aqueous solution of methanol, ethanol or propanol with a concentration ≤ 5%.

[0021] Example 1 Detection of nematicidal activity of 1-(9H-carbazol-9-yl)-2-((1-methyl-1H-tetrazol-5-yl)thio)propane-1-1

[0022] 1. Sample preparation

[0023] Dissolve 0.5 - 1.5 mg of 1-(9H-carbazol-9-yl)-2-((1-methyl-1H-tetrazol-5-yl)thio)propane-1-1 in DMSO (dimethyl sulfoxide), and dilute it with 4% DMSO solution to obtain the test liquid. The dilution concentrations of each test liquid are: 0.03 μg / ml, 0.05 μg / ml, 0.1 μg / ml, 0.3 μg / ml, 0.5 μg / ml, 1 μg / ml, 3 μg / ml, 5 μg / ml, 10 μg / ml, 30 μg / ml, 50 μg / ml, and the mass concentration of DMSO in each test liquid is 0.4%; use water containing 0.4% DMSO as the blank control.

[0024] 2. Preparation of test nematodes

[0025] Wash the tomato roots infected with Meloidogyne incognita with water, pick the egg sacs of root-knot nematodes with a dissecting needle and place them in 0.4 M KCl solution. Wash and disinfect them successively with 4 ml of sterile water (three times), 1 ml of sterile penicillin-streptomycin double-antibody solution, and 3 ml of 0.1% NaClO solution in a 5 ml centrifuge tube. Remove the supernatant by brief centrifugation (8000 rpm for 30 seconds) in each step. Place the washed eggs in 0.4 M ZnCl2 solution and incubate for 48 hours. Collect the second-stage larvae with a pipette into a 1.5 ml centrifuge tube and enrich them by brief centrifugation (5000 rpm for 30 seconds) for standby.

[0026] In addition, test nematodes such as Meloidogyne javanica, Meloidogyne enterolobii, and Caenorhabditis elegans were also prepared according to conventional methods in this experiment.

[0027] 3. Test method

[0028] Take 100 μl of each test liquid prepared in step 1 into a 20-well plate, add 50 - 100 live nematodes prepared in step 2, place them at 25 °C, and check and calculate the mortality rate of nematodes under an optical microscope at 24 hours, 48 hours, and 72 hours respectively. The method for identifying death is: add 1 - 5 drops of 5% NaCl solution to the wells of the treatment plate, observe after 2 minutes. Dead worms are stiff and do not respond to needle stimulation, while live worms curl or wriggle.

[0029] Using the test solution without adding samples as a control, the entire experiment was repeated three times, and the average value of the three times was taken to calculate the corrected mortality rate.

[0030] Mortality rate % = (Number of dead nematodes / (Number of dead nematodes + Number of surviving nematodes)) × 100%

[0031] Corrected mortality rate % = Sample mortality rate – Control mortality rate

[0032] 4. Experimental results

[0033] 4.1 The nematicidal effect of 1-(9H-carbazol-9-yl)-2-((1-methyl-1H-tetrazol-5-yl)thio)propane-1,1 on Meloidogyne incognita is shown in Table 1 and Figure 2 as follows:

[0034] Table 1 Nematicidal results of 1-(9H-carbazol-9-yl)-2-((1-methyl-1H-tetrazol-5-yl)thio)propane-1,1 on Meloidogyne incognita

[0035]

[0036] 4.2 The nematicidal effect of 1-(9H-carbazol-9-yl)-2-((1-methyl-1H-tetrazol-5-yl)thio)propane-1,1 on Meloidogyne javanica is shown in Table 2 and Figure 3 as follows.

[0037] Table 2 Nematicidal results of 1-(9H-carbazol-9-yl)-2-((1-methyl-1H-tetrazol-5-yl)thio)propane-1,1 on Meloidogyne javanica

[0038]

[0039] 4.3 The nematicidal effect of 1-(9H-carbazol-9-yl)-2-((1-methyl-1H-tetrazol-5-yl)thio)propane-1,1 on Meloidogyne enterolobii is shown in Table 3 and Figure 4 as follows:

[0040] Table 3 Nematicidal results of 1-(9H-carbazol-9-yl)-2-((1-methyl-1H-tetrazol-5-yl)thio)propane-1,1 on Meloidogyne enterolobii

[0041]

[0042] 4.4 1-(9H-carbazol-9-yl)-2-((1-methyl-1H-tetrazol-5-yl)thio)propane-1,1 has no nematicidal activity against the non-plant pathogenic nematode Caenorhabditis elegans within 24 hours.

[0043] Result analysis: After measurement ( Figures 2-4 ), the median lethal doses LC 50 of 1-(9H-carbazol-9-yl)-2-((1-methyl-1H-tetrazol-5-yl)thio)propane-1-one against Meloidogyne incognita, Meloidogyne javanica and Meloidogyne enterolobii at 24 hours were 10.94 μg / ml, 14.46 μg / ml and 14.24 μg / ml respectively; the median lethal doses LC 50 of 1-(9H-carbazol-9-yl)-2-((1-methyl-1H-tetrazol-5-yl)thio)propane-1-one against Meloidogyne incognita, Meloidogyne javanica and Meloidogyne enterolobii at 48 hours were 10.71 μg / ml, 14.12 μg / ml and 13.59 μg / ml respectively, indicating that it has a strong toxic effect on Meloidogyne incognita, Meloidogyne javanica and Meloidogyne enterolobii, and has no toxic activity against the non-plant pathogenic nematode Caenorhabditis elegans, and can be used for the control of plant root-knot nematodes.

[0044] Example 2

[0045] An insecticide for controlling plant root-knot nematodes, the insecticide uses a 3% ethanol solution as a solvent and 1-(9H-carbazol-9-yl)-2-((1-methyl-1H-tetrazol-5-yl)thio)propane-1-one with a concentration of 50 μg / ml as an active ingredient.

[0046] Example 3

[0047] An insecticide for controlling plant root-knot nematodes, the insecticide uses a 3% ethanol solution as a solvent and 1-(9H-carbazol-9-yl)-2-((1-methyl-1H-tetrazol-5-yl)thio)propane-1-one with a concentration of 30 μg / ml as the main active ingredient.

[0048] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. Use of 1-(9H-carbazol-9-yl)-2-((1-methyl-1H-tetrazol-5-yl)thio)propane-1,1 in controlling plant root-knot nematodes, characterized in that, The structural formula of 1-(9H-carbazol-9-yl)-2-((1-methyl-1H-tetrazol-5-yl)thio)propane-1-1 is shown in Formula I as follows: I； For *Meloidogyne incognita*, *Meloidogyne javanica* and *Meloidogyne enterolobii*, the median lethal concentration LC 50 at 24 h was 10.94 μg / mL, 14.46 μg / mL and 14.24 μg / mL respectively, and the median lethal concentration LC 50 at 48 h was 10.71 μg / mL, 14.12 μg / mL and 13.59 μg / mL respectively.

2. A pharmaceutical composition for preventing and controlling plant root-knot nematodes, characterized in that, The pharmaceutical composition uses 1-(9H-carbazol-9-yl)-2-((1-methyl-1H-tetrazol-5-yl)thio)propane-1-1 described in claim 1 as the active ingredient.

3. A plant root-knot nematode insecticide based on the pharmaceutical composition described in claim 2, characterized in that, The dosage form of the pesticide is aqueous solution, aqueous emulsion, wettable powder, soluble powder, soluble granule, suspension, tablet or effervescent granule.

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