Application of pyrazine derivative in killing plant nematodes

Abstract

The invention relates to the technical field of organic chemistry, in particular to application of pyrazine compounds in the aspect of killing nematodes. The pyrazine compound has good nematicidal activity on pine wood nematodes, root-knot nematodes and aphelenchoides besseyi, and part of the pyrazine compound also has good activity on root knot nematode diseases caused by the root-knot nematodes, so that the pyrazine compound has good application prospects in the aspect of root knot nematode disease resistance.

Description

Technical Field

[0001] The present invention relates to the field of plant protection, and in particular to the use of pyrazine derivatives in killing plant nematodes. Background Art

[0002] Plant-parasitic nematodes are among the world's most notorious plant pathogens, with thousands of crops and trees susceptible to diseases caused by them (Ntalli, NG and Caboni, P., 2012. Botanical Nematicides: A Review. J. Agric. Food Chem. 60, 9929-9940). Nematode diseases have a significant negative impact on agricultural production, resulting in $173 billion in economic losses annually (Zhu, MC, Li, XM, Zhao, N., Yang, L., Zhang, KQ and Yang, JK, 2022. Regulatory Mechanism of Trap Formation in the Nematode-Trapping Fungi. J. Fungi. 8, 406). Nematode control has always been a challenge in agricultural production. Chemical nematicides are commonly used to reduce economic losses caused by nematodes (Fan, ZQ, Wang, LS, Qin, YK and Li, PC, 2023. Activity of chitin / chitosan / chitosan oligosaccharide against plantpathogenic nematodes and potential modes of application in agriculture: A review. Carbohyd. Polym. 306, 120592.). However, some nematicides have been banned or restricted due to harm to the environment and animals (Déri, J., Lehel, J., Laczay, P., Acsné, KL, Gaálné, DE and Szebeni, Z., 2009. Carbofuran poisoning in birds. 2. Environment protection and food safety aspects. Magy. Allatorvosok. 131, 335-341.). Currently, there are relatively few commercial nematicides, accounting for only 2.5% of the pesticide market, and most of them are traditional, outdated varieties (Castaneda-Alvarez, C. and Aballay, E., 2016. Rhizobacteria with nematicide aptitude: enzymes and compounds associated. World. J. Microb. Biot. 32, 203.).Although biopesticides are less harmful to the environment and animals, they are difficult to use widely due to their slow onset, short duration in the environment, and instability under adverse field conditions (Chandler, D., Bailey, AS, Tatchell, GM, Davidson, G., Greaves, J. and Grant, WP, 2011. The development, regulation and use of biopesticides for integrated pest management. Philos. TRSoc. B. 366, 1987-1998.). The use of chemical nematicides is still the main method for controlling nematodes (Ahmad, G., Khan, A., Khan, AA, Ali, A. and Mohhamad, HI, 2021. Biological control: a novel strategy for the control of the plant parasitic nematodes. Anton. Leeuw. Int. JG 114, 885-912.). In the scientific management of nematode diseases, the development of new nematicides with low environmental toxicity, low pesticide residues and high nematicidal efficiency has become an urgent and challenging task (Seo, SM, Kim, J., Koh, SH, Ahn, YJ and Park, IK, 2014. Nematicidal Activity of Natural Ester Compounds and Their Analogues against Pine Wood Nematode, Bursaphelenchus xylophilus. J. Agric. Food Chem. 62, 9103-9108.).

[0003] Pyrazines have a wide range of biological activities, such as insecticide, antibacterial and herbicidal activities. Gholivand, K., Mohammadpanah, F., Pooyan, M., Valmoozi, AAE, Sharifi, M., Mani-Varnosfaderani, A. and Hosseini, Z., 2019. Synthesis, crystal structure, insecticidal activities, molecular docking and QSAR studies of some new phospho guanidines and phosphopyrazines as cholinesterase inhibitors. Pestic. Biochem. Physiol. 157, 122-137., Kikutake, K., Furuya, T., Hasebe, M., Nagai, H. and Oda, M., 2020. Development of a novel fungicide, pyraziflumid. J Pestic Sci.45,184-190.,Ma,SJ,Zhao,H.,Liu,SJ,Tian,C.,Gao,M.,Wang,YZ,Dong,JAand Zhang,LH,2024.2,4-Di-tert-butylphenoland7-hydroxy-3-(2-methylpropyl)-2,3,6,7,8,8a-hexahydropyrrolo[1,2-a]

[0004] pyrazine-1,4-dione:two natural products from Serratia marcescens Ha1and their herbicidal activities.Pest Manag.Sci.80,1016-1025.). For example, Yang et al. (Yang,HP,Zhang,RF,Li,Z.,Maienfisch,P.and Xu,XY,2021.Design,synthesisand nematicidal activitives of trifluorobutene amide derivatives againstMeloidogyne incognita.Bioorg.Med.Chem.Lett.40,127917.) synthesized a series of trifluorobutaneamides containing pyrazine structures and tested the in vitro and in vivo activity of the target compounds against southern root-knot nematodes. The bioassay results showed that compounds A8 and A23 had good activity against southern root-knot nematodes, LC 50The values were 2.02 mg / L and 0.76 mg / L respectively. In particular, compound A8 showed good nematicidal activity in in vivo tests, with an inhibitory activity against southern root-knot nematodes of 56.25% at a concentration of 5 mg / L; Trinh et al. (Trinh, THT, Wang, SL, Nguyen, VB, Phan, TQ, Doan, MD, Tran, TPH, Nguyen, TH, Le, TAH, Ton, TQ and Nguyen, AD, 2022. Novel Nematocidal Compounds from Shrimp Shell Wastes Valorized by Bacillus velezensis RB.EK7 against Black Pepper Nematodes. AGRONOMY-BASEL.12) characterized the compounds produced by fermentation of Bacillus veleznesis RB.EK7 and found that hexahydropyrrolo[1,2-a]pyrazine-1,4-dione had moderate nematicidal activity against black pepper nematodes. At a concentration of 20 mg / mL, the lethality rate against the second-instar black pepper nematode was 64.2%, and the inhibition rate against its egg hatching was 57.9%. Song et al. (Song, WW, Dai, MM, Gao, SS, Mi, YD, Zhang, SJ, Wei, JY, Zhao, HH, Duan, FM, Liang, C. and Shi, QQ, 2024. Volatile organic compounds produced by Paenibacillus polymyxa J2-4 exhibit toxic activity against Meloidogyne incognita. Pest Manag. Sci. 80, 1289-1299.) studied the volatile organic compounds of Paenibacillus polymyxa J2-4, among which 2-isobutyl-3-methylpyrazine showed strong direct contact nematicidal and fumigant activity against the second-instar southern root-knot nematode, LC 50The results were as follows: 134.43 mg / L and 720.94 mg / L, respectively. In addition, in a pot experiment, it reduced the number of root knots by about 70%. Wu et al. (Wu, WT, Zeng, YL, Yan, XR, Wang, ZH, Guo, LW, Zhu, YY, Wang, Y. and He, XH, 2023. Volatile Organic Compounds of Bacillus velezensis GJ-7 against Meloidogyne hapla through Multiple Prevention and Control Modes. MOLECULES. 28) characterized the volatile organic compounds produced by Bacillus velezensis GJ-7 (Bacillus velezensis GJ-7), among which 2,5-dimethylpyrazine showed good contact killing activity against yellow root knot nematodes. After treating the nematodes for 48 hours, the LC of the second-stage larvae was 0.04. 90 It is 10.8μL / mL.

[0005] At present, there is no systematic research on the nematicidal activity of pyrazines at home and abroad. Summary of the Invention

[0006] The present invention aims to overcome the above disadvantages and provide a pyrazine derivative for use in the study of nematicidal activity.

[0007] A pyrazine derivative is used in the study of nematicidal activity, wherein the compound has the general structural formula shown in FIG:

[0008]

[0009] Furthermore, the above-mentioned application of pyrazine derivatives in the study of nematicidal activity, the specific compounds are as follows:

[0010] F1: 3-Chloropyrazine-2-carbonitrile

[0011] F2: 2-Bromo-5-chloro-pyrazine

[0012] F3: 2,3,5-trichloropyrazine

[0013] F4: Pyrazine-2,3-dicarbonitrile

[0014] F5: 6-Chloropyrazine-2-carbonitrile

[0015] F6: 3,6-Dichloropyrazine-2-carbonitrile

[0016] F7: 3-Chloro-5-(trifluoromethyl)pyrazine-2-carbonitrile

[0017] F8: 3,5-dichloro-6-ethylpyrazine-2-carboxamide

[0018] F9: 3,5-Dichloropyrazine-2-carboxamide

[0019] F10: 3,5-dichloro-2-iodopyrazine

[0020] F11: 3,6-difluoropyrazine-2-carbonitrile

[0021] F12: 3,5-Dichloropyrazine-2-carbonitrile

[0022] F13: 5,6-Dichloropyrazine-2,3-dicarbonitrile

[0023] Beneficial effects:

[0024] The pyrazine derivatives of the present invention have protective activity against tomatoes infected with root-knot nematodes through in vitro and in vivo nematode activity tests and can be used as potential nematicides. DETAILED DESCRIPTION

[0025] The specific embodiments of the present invention are further described in detail below, but the present invention is not limited to these embodiments. Any improvement or replacement based on the basic spirit of the present embodiment still falls within the scope of protection required by the claims of the present invention.

[0026] Example 1: In vitro activity test

[0027] The test compound was first fully dissolved in DMSO and then diluted with 1% Tween 80 aqueous solution to the required concentration of the test solution. The commercial drugs fluopyram and tioxazafen were used as positive controls, and the test solution without the test compound was used as the negative control (CK). The initial screening concentrations were 50 and 100 mg / L, and the nematode-killing activity of the compounds against pine wood nematodes, root-knot nematodes and rice stem-tipped nematodes was determined by the insect immersion method. The half-lethal concentration (LC50) of the compounds with better activity against nematodes was further tested at 5 different concentration gradients. 50). Add the prepared nematode suspension to a 48-well biochemical culture plate, 10 μL per well (approximately 50 worms), then add 300 μL of the treatment group test solution to each well, with three parallels for each treatment. Place the 48-well biochemical culture plate in a 27°C biochemical incubator in the dark. After 72 hours, count the deaths of nematodes (when the nematode body is straight or remains motionless after being touched with a needle, it is considered dead) and calculate the mortality rate and adjusted mortality rate. The experiment was repeated three times, and the results are expressed as mean ± deviation. The mortality rate and adjusted mortality rate of nematodes are calculated using the following formula (no adjusted mortality rate is used when the mortality rate of the CK group is less than 5%):

[0028] Mortality rate (%) = number of dead nematodes in the treatment group / total number of nematodes in the treatment group × 100

[0029] Corrected mortality rate (%) = (mortality rate of treatment group (%) - mortality rate of blank group (%)) / (100 - mortality rate of blank group (%)) × 100

[0030] Table 1. Preliminary screening activity of 28 compounds against three nematodes

[0031]

[0032]

[0033] The results shown in Table 1 indicate that some compounds have good therapeutic activity against the three nematodes, wherein compounds F6, F11 and F12 all had a 100% mortality rate against the three nematodes at a concentration of 50 mg / L.

[0034] Table 2. LC values of some compounds against pine wood nematodes 50 value

[0035]

[0036] Table 3. LC values of some compounds against root-knot nematodes 50 value

[0037]

[0038] Table 4. LC of some compounds against dry-axylated nematodes 50 value

[0039]

[0040] As shown in Table 2-4, the LC values of some compounds are 50 The results were significantly lower than those of the control. For example, all pyrazine compounds in Table 2 were significantly lower than those of tioxazafen; and F12 in Table 3 was significantly lower than that of fluopyram.

[0041] Test Example 2: In vivo activity test

[0042] In vivo nematode testing was conducted using an in vitro test tube method, with a soil-sand ratio of 3:1. F12 and fluopyram were mixed at a concentration of 100 mg / L. The negative control (CK) was treated with fluopyram alone, while the positive control was treated with fluopyram. Three replicates were performed for each concentration. Fourteen-day-old tomato seedlings were re-transplanted into sterilized soil (one seedling per test tube, 37.8 × 107 mm) and allowed to establish roots for 5 days. Five days later, a hole was punched into the root of each seedling and 5 mL of the drug solution was added for 6 hours. Approximately 1200 live root-knot nematodes were then inoculated into the roots of each host plant. All test tubes were incubated at 25°C for 14 days, with 10 hours of incubation in the day and 14 hours in the dark (Chen et al., 2019). After 14 days, the effects of each treatment on tomato plant fresh weight, root length, plant height, and root knot number were recorded, and the root knot reduction rate was calculated. Water was supplemented appropriately during planting.

[0043] Root knot reduction rate = (number of root knots in the control group - number of root knots in the treatment group) / number of root knots in the control group × 100%.

[0044] Table 5. In vivo activity of compound F12 against root-knot nematodes

[0045]

[0046] The results shown in Table 5 indicate that at a concentration of 100 mg / L, compound F12 reduced the number of root knots to a certain extent.

Claims

1. Use of a pyrazine derivative in killing plant nematodes.

2. The use of a pyrazine derivative as claimed in claim 1 in killing plant nematodes, wherein the general structural formula of the compound is shown as 1:

3. The use of a pyrazine derivative in killing plant nematodes according to claim 2, characterized in that: The derivatives include but are not limited to: F1: 3-Chloropyrazine-2-carbonitrile F2: 2-Bromo-5-chloro-pyrazine F3: 2,3,5-trichloropyrazine F4: Pyrazine-2,3-dicarbonitrile F5: 6-Chloropyrazine-2-carbonitrile F6: 3,6-Dichloropyrazine-2-carbonitrile F7: 3-Chloro-5-(trifluoromethyl)pyrazine-2-carbonitrile F8: 3,5-dichloro-6-ethylpyrazine-2-carboxamide F9: 3,5-Dichloropyrazine-2-carboxamide F10: 3,5-dichloro-2-iodopyrazine F11: 3,6-difluoropyrazine-2-carbonitrile F12: 3,5-Dichloropyrazine-2-carbonitrile F13: 5,6-Dichloropyrazine-2,3-dicarbonitrile

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