Application of ketone compound as prodenia litura insecticidal synergist and method

Abstract

The invention belongs to the technical field of pest control, and relates to application of a ketone compound as a prodenia litura insecticidal synergist and a method. The ketone compound is 4-(4-iodophenyl)-3, 4-dihydrobenzo [h] quinoline-2 (1H)-ketone, and the ketone compound is used for inhibiting cytochrome p450 enzyme of prodenia litura; the prodenia litura cytochrome p450 enzyme is a CYP6AE48 enzyme, and the prodenia litura cytochrome p450 The compound can well inhibit the activity of a prodenia litura CYP6AE48 enzyme, so that the prodenia litura CYP6AE48 enzyme cannot normally play a role in detoxifying lambda-cyhalothrin, the control effect of lambda-cyhalothrin is further improved, and the compound can be used as a pesticide synergist to play a synergistic role in pest control.

Description

Technical Field

[0001] The present invention belongs to the technical field of pest control, and relates to the use and method of a ketone compound as a synergist for killing Spodoptera litura Background Art

[0002] Spodoptera litura Spodoptera litura belongs to the insects of Noctuidae in Lepidoptera, and has the characteristics of polyphagy, wide distribution, long migration distance and high resistance; it is mainly distributed in tropical and subtropical regions of Asia, Mediterranean regions of Europe and Africa, and can harm 389 species of plants in 109 families. It can occur in multiple generations in a year, and the phenomenon of overlapping generations is serious.

[0003] Spodoptera litura can feed on sweet potatoes, cotton, soybeans, tobacco, as well as various crops of cruciferae, solanaceae and cucurbitaceae, and is widely distributed all over the world. This insect has strong reproductive ability, and a single female can lay about a thousand eggs, and it is extremely easy to break out into disasters in a short time, bringing great losses to agricultural production.

[0004] At present, the control of Spodoptera litura mainly relies on chemical agents. Long-term and single use of the same type of agents is likely to lead to drug resistance, may also pollute the environment, and cause harm to non-target organisms. If chemical agents are not applied according to the safe interval period, it may increase the risk of agricultural product residues. Chemical control requires frequent use of drugs, which may increase costs in the long term and has a strong dependence.

[0005] The insect cytochrome P450 enzyme system (Cytochrome P450 monooxygenase) is widely distributed in the endoplasmic reticulum and mitochondria of insect cells. Its main functions include participating in the synthesis and degradation of key hormones for insect growth and development such as ecdysteroid and juvenile hormone, and catalyzing basic metabolic reactions such as fatty acid hydroxylation and steroid synthesis. At the same time, this enzyme system can also activate and decompose plant toxins (such as alkaloids) and environmental pollutants to reduce their toxicity; some insecticides (such as pyrethroids) can be activated by P450 into more toxic substances, resulting in insect drug resistance. It assists in the respiratory process and participates in the electron transport chain during the process of CO2 elimination to regulate cell respiration function.

[0006] By developing P450 enzyme inhibitors related to detoxification metabolism, the insect resistance to chemical pesticides can be reduced, and the control effect of chemical agents in agricultural production can be enhanced. Summary of the Invention

[0007] In order to enrich the types of existing pesticide synergists and further enhance the pest control effect, the present invention takes Spodoptera litura CYP6AE48 enzyme (a P450 enzyme related to detoxification metabolism) as the main target, screens a ketone compound, and proves that this compound has an enhancing or promoting effect on the control effect of lambda-cyhalothrin.

[0008] To achieve this technical objective, the present invention adopts the following technical solutions: Use of a ketone compound as a synergist for killing Spodoptera litura. The ketone compound is 4-(4-iodophenyl)-3,4-dihydrobenzo[h]quinolin-2(1H)-one, and the structural formula of the ketone compound is shown as follows: .

[0009] Furthermore, the ketone compound is used to inhibit the cytochrome p450 enzyme of Spodoptera litura.

[0010] Furthermore, the cytochrome p450 enzyme of Spodoptera litura is CYP6AE48 enzyme.

[0011] A method for enhancing the chemical control effect on Spodoptera litura, the method includes: using the ketone compound as an inhibitor of the cytochrome p450 enzyme of Spodoptera litura, acting on Spodoptera litura, thereby enhancing the chemical control effect on Spodoptera litura; The ketone compound is 4-(4-iodophenyl)-3,4-dihydrobenzo[h]quinolin-2(1H)-one.

[0012] Furthermore, the cytochrome p450 enzyme of Spodoptera litura is CYP6AE48 enzyme, and it has been found that this enzyme can decompose plant toxins and environmental pollutants and reduce their toxicity Furthermore, the ketone compound is dissolved in dimethyl sulfoxide to prepare a solution with a concentration of 8-10 g / L, and the usage amount of the solution is 16-20 μg / head.

[0013] Furthermore, the chemical control is carried out using lambda-cyhalothrin for prevention and treatment.

[0014] Furthermore, the ketone compound makes the effect of lambda-cyhalothrin in controlling Spodoptera litura increase by 7.79, 17.05, and 16.31 times at 24, 48, and 72 h respectively.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a ketone compound screened with the CYP6AE48 enzyme of Spodoptera litura as the main target, which is 4-(4-iodophenyl)-3,4-dihydrobenzo[h]quinolin-2(1H)-one; this compound makes the effect of lambda-cyhalothrin in controlling Spodoptera litura increase by 7.79, 17.05, and 16.31 times at 24, 48, and 72 h. It shows that this compound can better inhibit the activity of the CYP6AE48 enzyme of Spodoptera litura, making it unable to normally play its detoxification function on lambda-cyhalothrin, thereby enhancing the control effect of lambda-cyhalothrin. This compound can be used as a pesticide synergist to play a synergistic role in pest control.

[0016] Existing P450 enzyme inhibitors (such as piperonyl butoxide) mainly inhibit P450 enzymes related to biosynthesis reactions, while P450 enzymes related to detoxification metabolism are the main reasons for the resistance and cross-resistance of most pests to pesticides, which is more important for pest control. The present invention targets the P450 enzyme CYP6AE48 related to the detoxification metabolism of Spodoptera litura, and screens out a P450 enzyme inhibitor related to detoxification metabolism, making up for the technical defect of the relative lack of such enzyme inhibitors, which has important inspiration and guiding significance for the future research of pesticide synergists. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a molecular docking result diagram of CYP6AE48 enzyme and ketone compounds. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] The present invention will be described below in conjunction with the embodiments. The technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0019] The experimental methods in the following embodiments are all conventional methods unless otherwise specified, and are carried out according to the techniques or conditions described in the literature in this field or according to the product instructions. The materials, reagents, etc. used in the following embodiments can be obtained from commercial channels unless otherwise specified.

[0020] In the following embodiments, the ketone compound is: 4-(4-iodophenyl)-3,4-dihydrobenzo[h]quinolin-2(1H)-one (purity 99%), and this compound is purchased from SPECS company.

[0021] The structural formula of the ketone compound is shown as follows:

[0022] The larvae of Spodoptera litura are independently cultured by the Laboratory of Environment-Friendly Pesticides, Sichuan Agricultural University.

[0023] Example 1: This example describes the killing effect of lambda-cyhalothrin alone on Spodoptera litura.

[0024] Test method: Weigh the original drug of lambda-cyhalothrin, prepare a 1 g / L mother liquor with acetone as the solvent, and then dilute it to 3, 2, 1.5, 1, 0.5 mg / L respectively to obtain lambda-cyhalothrin solutions.

[0025] Using the 3rd instar larvae of Spodoptera litura as test insects, the beta-cyhalothrin solution was dripped onto the pronotum of the larvae with a micro-dropper, 1 μL for each larva. After natural air drying, they were placed in an incubator with a temperature of 27 ± 1 °C, a relative humidity of 70%, and a light duration of 12 h. Acetone was used as the control group, and the remaining treatment steps were the same. 20 larvae were treated in each petri dish, with 3 replicates. The results were observed at 24, 48, and 72 h respectively, and the number of dead insects was recorded. If the larva did not wriggle when gently touched with a brush, it was considered dead. The DPS 9.01 software was used to calculate the toxicity regression equation, correlation coefficient, and LC 50 。

[0026] Test results: See Table 1; at 24, 48, and 72 h, when using beta-cyhalothrin alone, the LC 50 values were 2.7635, 2.6984, and 1.7270 mg / L respectively.

[0027] Table 1. Application effect of using beta-cyhalothrin alone

[0028] Example 2: This example describes the application effect of using the ketone compound as a synergist when using beta-cyhalothrin.

[0029] Test method: Weigh the technical beta-cyhalothrin, and prepare a stock solution of 1 g / L with acetone as the solvent, and then dilute it to 0.5, 1, 1.5, 2, and 3 mg / L to obtain the beta-cyhalothrin solution. Separately, using dimethyl sulfoxide as the solvent, prepare the solution of the ketone compound with a concentration of 8 - 10 g / L.

[0030] Using the 3rd instar larvae of Spodoptera litura as test insects, the solution of the ketone compound was dripped onto the pronotum of the larvae with a micro-dropper, 16 - 20 μg for each larva. After natural air drying for 1 h, the beta-cyhalothrin solution was dripped in the same way, 1 μL for each larva. After dripping, they were placed in an incubator with a temperature of 27 ± 1 °C, a relative humidity of 70%, and a light duration of 12 h. In the control group, dimethyl sulfoxide was used to replace the solution of the ketone compound, and the remaining treatment steps were the same. 20 larvae were treated in each petri dish, with 3 replicates. The results were observed at 24, 48, and 72 h respectively, and the number of dead insects was recorded. If the larva did not wriggle when gently touched with a brush, it was considered dead. The DPS 9.01 software was used to calculate the toxicity regression equation, correlation coefficient, and LC 50 and calculate the synergistic ratio (SR).

[0031] Synergistic ratio (SR) = LC of beta-cyhalothrin when used alone 50 / LC of beta-cyhalothrin when the ketone compound is used as a synergist 50。

[0032] Test results: See Table 2; When using lambda-cyhalothrin with the ketone compound as a synergist at 24, 48, and 72 h, the LC 50 values are 0.3549, 0.1583, and 0.1059 mg / L respectively.

[0033] Table 2. Application effects of lambda-cyhalothrin when using the ketone compound as a synergist

[0034] As can be seen from Table 1 and Table 2, at 24, 48, and 72 h, the LC 50 values of lambda-cyhalothrin when adding the ketone compound are significantly lower than the LC 50 when using lambda-cyhalothrin alone, indicating that the CYP6AE48 enzyme of Spodoptera litura is inhibited by the ketone compound and cannot normally exert its detoxification function on lambda-cyhalothrin. Therefore, the effect of using lambda-cyhalothrin when adding the ketone compound is better and meets the expectations. In addition, at 24, 48, and 72 h, the synergistic multiples are 7.79, 17.05, and 16.31 times respectively, all greater than 1, indicating that the application effect of the ketone compound is good.

[0035] Example 3: This example describes the application effect of piperonyl butoxide as a synergist when using lambda-cyhalothrin.

[0036] Test method: Weigh the technical material of lambda-cyhalothrin, prepare a stock solution of 1 g / L with acetone as the solvent, and then dilute it to 0.5, 1, 1.5, 2, 3 mg / L to obtain lambda-cyhalothrin solutions. Separately, prepare a piperonyl butoxide solution with a concentration of 8 - 10 g / L using dimethyl sulfoxide as the solvent.

[0037] Using the 3rd instar larvae of Spodoptera litura as test insects, drip piperonyl butoxide onto the pronotum of the larvae with a microapplicator, 16 - 20 μg per larva. After natural air drying for 1 h, drip the above-mentioned lambda-cyhalothrin solution in the same method, 1 μl per larva. After dripping, put them into an incubator with a temperature of 27 ± 1 °C, a relative humidity of 70%, and a light duration of 12 h. The control group uses dimethyl sulfoxide to replace piperonyl butoxide, and the remaining treatment steps are the same. Each petri dish is treated with 20 insects, repeated 3 times. Observe the results after 24, 48, and 72 h respectively, record the number of dead insects, and consider the larvae not wriggling when gently touched with a brush as dead. Use DPS 9.01 software to calculate the toxicity regression equation, correlation coefficient, and LC 50 and calculate the synergistic ratio (SR).

[0038] Synergistic ratio (SR) = LC 50 when using lambda-cyhalothrin alone / LC 50 Test results: See Table 3; When piperonyl butoxide was used as a synergist, the LC 50 values of lambda-cyhalothrin at 24, 48, and 72 h were 0.5338, 0.4553, and 0.3509 mg / L, respectively.

[0039] Table 3. Application effects of lambda-cyhalothrin when piperonyl butoxide was used as a synergist

[0040] It can be seen from Table 2 and Table 3 that at 24, 48, and 72 h, the LC 50 of lambda-cyhalothrin with piperonyl butoxide added was higher than that of lambda-cyhalothrin with ketone compounds added. 50 This indicates that the effect is better when ketone compounds are used as synergists. Calculated from Table 1 and Table 3, at 24, 48, and 72 h, the synergistic ratios of lambda-cyhalothrin with piperonyl butoxide added were 5.26, 6.03, and 5.38, respectively, all of which were less than the synergistic ratios when ketone compounds were used as synergists, which can also prove the above conclusion.

[0041] In summary, the present invention uses Spodoptera litura CYP6AE48 enzyme as the main target and screens a ketone compound, which is 4-(4-iodophenyl)-3,4-dihydrobenzo[h]quinolin-2(1H)-one. The molecular docking results show that there are van der Waals forces, Pi-Pi T-shaped (π-π stacking), Pi-Alkyl (a non-bonding interaction), Pi-Cation (cation-π interaction), Conventional Hydrogen Bond, Pi-DonorHydrogen Bond, Pi-Sulfur (the interaction between the π electron cloud on the aromatic ring and the sulfur atom), and Alkyl between the ketone compound and CYP6AE48 enzyme; as shown below, leucine (LEU) 460, leucine (LEU) 391, leucine (LEU) 318, arginine (ARG) 131, glycine (GLY) 455, threonine (THR) 326, threonine (THR) 330, and proline (PRO) 453 in the enzyme bind to the compound through van der Waals forces. Arginine (ARG) 459 in the enzyme binds to the compound through ConventionalHydrogen Bond. Arginine (ARG) 104 in the enzyme binds to the compound through Pi-Cation. Isoleucine (ILE) 462 in the enzyme binds to the compound through Pi-DonorHydrogen Bond. Cysteine (CYS) 461 in the enzyme binds to the compound through Pi-Sulfur. Phenylalanine (PHE) 120 in the enzyme binds to the compound through Pi-Pi T-shaped. Leucine (LEU) 119, leucine (LEU) 388, and leucine (LEU) 382 in the enzyme bind to the compound through Alkyl. Alanine (ALA) 322, valine (VAL) 387, and phenylalanine (PHE) 454 in the enzyme bind to the compound through Pi-Alkyl.

[0042] It is known through experiments that the compound has a good inhibitory effect on Spodoptera litura CYP6AE48 enzyme, preventing its degradation of lambda-cyhalothrin, and is expected to play a synergistic role as a pesticide synergist in pest control.

[0043] The above-described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by relevant deductions and substitutions made by those of ordinary skill in the art under the condition of the inventive concept of the present invention without creative efforts belong to the scope of protection of the present invention.

Claims

1. Use of a ketone compound as a synergist for killing Spodoptera litura, characterized in that, The ketone compound is 4-(4-iodophenyl)-3,4-dihydrobenzo[h]quinolin-2(1H)-one, and the structural formula of the ketone compound is as follows: 。 2. The use according to claim 1, characterized in that, The ketone compound is used to inhibit the cytochrome p450 enzyme of Spodoptera litura.

3. The use according to claim 2, characterized in that, The cytochrome p450 enzyme of Spodoptera litura is CYP6AE48 enzyme.

4. A method for enhancing the chemical control effect of Spodoptera litura, characterized in that, The method includes: using the ketone compound as an inhibitor of the cytochrome p450 enzyme of Spodoptera litura, acting on Spodoptera litura, and then improving the chemical control effect of Spodoptera litura; The ketone compound is 4-(4-iodophenyl)-3,4-dihydrobenzo[h]quinolin-2(1H)-one.

5. The method according to claim 4, wherein The cytochrome p450 enzyme of Spodoptera litura is CYP6AE48 enzyme.

6. The method according to claim 4, characterized in that The ketone compound is dissolved in dimethyl sulfoxide to prepare a solution with a concentration of 8-10 g / L, and the dosage of the solution is 16-20 μg / head.

7. The method according to claim 4, wherein The chemical control is to use lambda-cyhalothrin for control.

8. The method according to claim 7, characterized in that The ketone compound makes the control effect of lambda-cyhalothrin against Spodoptera litura increase by 7.79, 17.05, and 16.31 times at 24, 48, and 72 h respectively.

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