Key Laboratory of Plant Protection Resources and Pest Management of Ministry of Education, College of Plant Protection, Northwest A&F University, Yangling, China.
Yantai City Research Centre for Rural Development of Chinese Academy of Social Sciences, Yantai, China.
Pest Manag Sci. 2024 Feb;80(2):885-895. doi: 10.1002/ps.7824. Epub 2023 Nov 10.
Insect glutathione S-transferases (GSTs), a multifunctional protein family, play a crucial role in detoxification of plant defensive compounds. However, they have been rarely investigated in Sitodiplosis mosellana, a destructive pest of wheat worldwide. In this study, we characterized for the first time a delta (SmGSTd1) and two epsilon GST genes (SmGSTe1 and SmGSTe2) and analyzed their expression patterns and functions associated with adaptation to host plant defense in this species.
Expression of these SmGST genes greatly increased in S. mosellana larvae feeding on resistant wheat varieties Kenong1006, Shanmai139 and Jinmai47 which contain higher tannin and ferulic acid, the major defensive compounds of wheat against this pest, compared with those feeding on susceptible varieties Xinong822, Xinong88 and Xiaoyan22. Their expression was also tissue-specific, most predominant in larval midgut. Recombinant SmGSTs expressed in Escherichia coli could catalyze the conjugation of 1-chloro-2,4-dinitrobenzene, with activity peak at pH around 7.0 and temperature between 30 and 40 °C. Notably, they could metabolize tannin and ferulic acid, with the strongest metabolic ability by SmGSTe2 against two compounds, followed by SmGSTd1 on tannin, and SmGSTe1 on ferulic acid.
The results suggest that these SmGSTs are important in metabolizing wheat defensive chemicals during feeding, which may be related to host plant adaptation of S. mosellana. Our study has provided information for future investigation and development of strategies such as host-induced gene silencing of insect-detoxifying genes for managing pest adaptation. © 2023 Society of Chemical Industry.
昆虫谷胱甘肽 S-转移酶（GSTs）是一个多功能蛋白家族，在解毒植物防御化合物方面起着至关重要的作用。然而，它们在世界性的小麦破坏性害虫麦红吸浆虫中很少被研究。在这项研究中，我们首次对一个δ（SmGSTd1）和两个ε GST 基因（SmGSTe1 和 SmGSTe2）进行了特征描述，并分析了它们与适应宿主植物防御相关的表达模式和功能。
与在易感品种新冬 822、新冬 88 和小偃 22 上取食相比，在取食含单宁和阿魏酸等主要防御化合物较高的抗小麦品种科农 1006、山麦 139 和金麦 47 时，这些 SmGST 基因在麦红吸浆虫幼虫中的表达大大增加。它们的表达也具有组织特异性，在幼虫中肠中最为显著。在大肠杆菌中表达的重组 SmGSTs 可以催化 1-氯-2,4-二硝基苯的共轭反应，在 pH 约为 7.0 和温度在 30 到 40°C 之间时达到活性峰值。值得注意的是，它们可以代谢单宁和阿魏酸，SmGSTe2 对这两种化合物的代谢能力最强，其次是 SmGSTd1 对单宁，SmGSTe1 对阿魏酸。
结果表明，这些 SmGSTs 在取食过程中对代谢小麦防御化学物质很重要，这可能与麦红吸浆虫对宿主植物的适应有关。我们的研究为未来调查和开发策略提供了信息，例如利用昆虫解毒基因的寄主诱导基因沉默来管理害虫的适应。© 2023 化学工业协会。
