National Demonstration Center for Experimental Crop Science Education, Sichuan Agricultural University, Chengdu 611130, China; Biorational Pesticide Research Lab, Sichuan Agricultural University, Chengdu 611130, China.
National Demonstration Center for Experimental Crop Science Education, Sichuan Agricultural University, Chengdu 611130, China; Biorational Pesticide Research Lab, Sichuan Agricultural University, Chengdu 611130, China.
Pestic Biochem Physiol. 2021 Jan;171:104723. doi: 10.1016/j.pestbp.2020.104723. Epub 2020 Oct 14.
The white-backed planthopper, Sogatella furcifera (Horváth) (Hemiptera, Delphacidae), is an energetic rice insect pest in rice production or rice-growing areas. Due to excessive use of the chemical insecticide, S. furcifera has produced the high resistance to some frequently used insecticides. In this paper, the resistance levels of S. furcifera from the eight different areas of Sichuan Province against the five chemicals were monitored by using the rice seedling dipping during 2017-2018 to understand the resistance levels. The results showed that most of all populations have developed low or moderate level of resistance for chlorpyrifos (3.4 to 44.3-fold) and thiamethoxam (3.9- to 15.5-fold), the populations in the LS (1.7 to 5.4- fold)and WS (1.6 to 5.0- fold) regions were still sensitive or low resistance levels compared with other local populations. Almost all populations displayed the susceptible to imidacloprid (0.9- to 5.0-fold), buprofezin (0.9- to 4.3-fold) or low levels of resistance to pymetrozine (1.5- to 6.8-fold). The synergism experiment indicated that P450 enzymes may be important contributed to the metabolic detoxification of chlorpyrifos. The cross-resistance bioassay showed that there was no cross-resistance between chlorpyrifos and triflumezopyrim, but for sulfoxaflor, in the XY17 population. The relative expression level of twelve insecticide resistant-related P450 genes were analyzed by using qRT-PCR and found that CYP4C77, CYP418A1, CYP418A2, CYP408A3 and CYP6ER4 were significantly more expressed in the 3rd-instar nymph of the XY17 and XY18 field populations. To determine the main resistant-related P450 gene for chlorpyrifos, the relative expression level of five P450 genes were detected by using qRT-PCR from the G2 and G4 generation of XY17 under the pressure with LC of chlorpyrifos. The results showed that CYP6ER4 was significantly up-regulated expression in XY17 G2 and G4 generations population over 700-fold (P < 0.01). The full length and proteins tertiary structure were also cloned and predicted. Meanwhile, the function of CYP6ER4 was analyzed by RNA interference and the results indicated that the relative expression of CYP6ER4 in the XY17 (G4) population after injected dsRNA was lower than that in the dsGFP injected group. Moreover, the mortality rates of the S. furcifera treated with the LC concentration of chlorpyrifos after dsRNA microinjection was significantly higher than that of the dsGFP injected group 72 h after treatment (P < 0.01). Therefore, the overexpression of CYP6ER4 may be one of the primary factors in the development of chlorpyrifos resistance in S. furcifera.
白背飞虱，褐飞虱（ Horváth ）（半翅目，飞虱科），是水稻生产或水稻种植区中一种活跃的水稻虫害。由于过度使用化学杀虫剂，褐飞虱对一些常用杀虫剂产生了高抗药性。在本文中，我们在 2017-2018 年期间通过水稻种子浸渍法监测了来自四川省八个不同地区的褐飞虱对五种化学物质的抗药性水平，以了解其抗药性水平。结果表明，大多数种群对毒死蜱（ 3.4 至 44.3 倍）和噻虫嗪（ 3.9 至 15.5 倍）表现出低或中度水平的抗性，LS （ 1.7 至 5.4- 倍）和 WS （ 1.6 至 5.0- 倍）地区的种群与其他当地种群相比仍然具有敏感或低抗药性水平。几乎所有种群对吡虫啉（ 0.9 至 5.0 倍），噻嗪酮（ 0.9 至 4.3 倍）或对吡丙醚（ 1.5 至 6.8 倍）表现出易感性。协同作用实验表明，P450 酶可能是代谢解毒毒死蜱的重要因素。交叉抗性生物测定表明，XY17 种群中氯氟吡氧乙酸与三氟甲吡醚之间没有交叉抗性，但对硫氟肟酯有交叉抗性。通过 qRT-PCR 分析了 12 种与杀虫剂抗性相关的 P450 基因的相对表达水平，发现 CYP4C77 ， CYP418A1 ， CYP418A2 ， CYP408A3 和 CYP6ER4 在 XY17 和 XY18 田间种群的 3 龄若虫中表达明显更高。为了确定对毒死蜱的主要抗性相关 P450 基因，我们通过 qRT-PCR 检测了 XY17 在 LC 压力下 G2 和 G4 代的 5 个 P450 基因的相对表达水平。结果表明，CYP6ER4 在 XY17 G2 和 G4 代种群中的表达水平显著上调了 700 倍以上（ P < 0.01 ）。还克隆并预测了全长和蛋白质三级结构。同时，通过 RNA 干扰分析了 CYP6ER4 的功能，结果表明，注射 dsRNA 后，XY17 （ G4 ）种群中 CYP6ER4 的相对表达水平低于 dsGFP 注射组。此外，dsRNA 微注射后，处理 LC 浓度毒死蜱的褐飞虱的死亡率在 72 小时后明显高于 dsGFP 注射组（ P < 0.01 ）。因此， CYP6ER4 的过表达可能是褐飞虱对毒死蜱产生抗药性的主要因素之一。
