Biorational Pesticide Research Lab, Sichuan Agricultural University, Chengdu 611130, China.
Sichuan Provincial Plant Protection Station, Department of Agriculture, Chengdu 610041, China.
Pestic Biochem Physiol. 2021 Jan;171:104720. doi: 10.1016/j.pestbp.2020.104720. Epub 2020 Oct 7.
Chilo suppressalis Walker (Lepidoptera: Crambidae) is a widely destructive pest occurring in rice, particularly in the rice-growing regions of Asia. In recent years, C. suppressalis has developed resistance to several insecticides because of the extensive use of insecticides. The resistance levels to four insecticides were determined among populations from different regions of Sichuan Province, China, using a drop-method bioassay. Based on LC values of a laboratory susceptible strain, all field populations showed moderate level of resistance to triazophos (23.9- to 83.5-fold) and were either susceptible or had a low level of resistance to abamectin (2.1- to 5.8-fold). All field-collected populations had a low or moderate level of resistance to chlorpyrifos (1.7- to 47.1-fold) and monosultap (2.7- to 13.5-fold). The synergism experiment indicated that the resistance of the XW19 to triazophos may be associated with cytochrome P450 monooxygenases (P450s), with the highest synergistic ratio (SR) of 3.05-fold and increased ratio (IR) of 2.28-fold for piperonylbutoxide (PBO). The P450 activity of the TJ19 population was the greatest among the six field populations. Moreover, the relative expression levels of four resistance-related P450 genes were detected with qRT-PCR, and the results indicated that CYP324A12, CYP321F3 and CYP9A68 were overexpressed in the resistant population, especially in the XW19 population (by 1.2-, 3.4 -, and 18.0-fold, respectively). In addition, the relative expression levels of CYP9A68 among the CZ19 and TJ19 populations were also enhanced 10.5- and 24.9-fold, respectively. These results suggested that CYP324A12, CYP321F3 and CYP9A68 may be related to the resistance development of C. suppressalis to triazophos.
二化螟（Lepidoptera: Crambidae）是一种广泛破坏性的害虫，发生在水稻上，特别是在亚洲的水稻种植区。近年来，由于杀虫剂的广泛使用，二化螟对几种杀虫剂产生了抗性。本研究采用点滴法生物测定法，测定了来自中国四川省不同地区种群对 4 种杀虫剂的抗性水平。基于实验室敏感品系的 LC 值，所有田间种群对三唑磷（23.9-83.5 倍）均表现出中等水平的抗性，对阿维菌素（2.1-5.8 倍）表现为敏感或低水平抗性。所有田间采集的种群对毒死蜱（1.7-47.1 倍）和单甲脒（2.7-13.5 倍）均表现出低或中等水平的抗性。增效实验表明，XW19 对三唑磷的抗性可能与细胞色素 P450 单加氧酶（P450s）有关，增效比值（SR）最高为 3.05 倍，增效比（IR）最高为 2.28 倍。对胡椒基丁醚（PBO）的抗性。TJ19 种群的 P450 活性在六个田间种群中最大。此外，通过 qRT-PCR 检测了四个抗性相关 P450 基因的相对表达水平，结果表明，在抗性种群中，CYP324A12、CYP321F3 和 CYP9A68 基因过度表达，尤其是在 XW19 种群中（分别为 1.2 倍、3.4 倍和 18.0 倍）。此外，CZ19 和 TJ19 种群中 CYP9A68 的相对表达水平也分别增强了 10.5 倍和 24.9 倍。这些结果表明，CYP324A12、CYP321F3 和 CYP9A68 可能与二化螟对三唑磷的抗性发展有关。
