CSIRO Materials Science and Engineering and CSIRO Food and Nutritional Sciences, Sydney Laboratory, North Ryde, NSW, Australia.
Pest Manag Sci. 2011 Nov;67(11):1457-67. doi: 10.1002/ps.2200. Epub 2011 May 18.
Certain bisacylhydrazine compounds such as tebufenozide (RH5992) have been shown to act as order-specific insecticides. Their compatibility with predatory Heteroptera, which are used as biological control agents, has also been demonstrated. However, the molecular mode of action of these ecdysone agonists has not been explored in a heteropteran, much less one that is a significant agricultural pest, such as Nezara viridula.
Alternatively spliced ligand-binding regions of the N. viridula ecdysone receptor were expressed, purified and characterised by 2D gel analysis, mass spectrometry, homology modelling and competitive binding of a bisacylhydrazine insecticidal compound (RH5992) and various ecdysteroids. Ligand binding by the two splice isoforms was indistinguishable, and relative affinities were found to occur in the order muristerone A > ponasterone A > 20-hydroxyecdysone > inokosterone > RH5992 > α-ecdysone.
The predicted difference in amino acid sequence between the ligand-binding domains of the N. viridula ecdysone receptor splice variants was verified by mass spectrometry. Both splice variant isoforms exhibit a greater affinity for the bisacylhydrazine insecticide RH5992 than do the other hemipteran ecdysone receptors characterised to date. Their affinities for a range of ecdysteroids also distinguish them from the ecdysone receptors of other Hemiptera characterised thus far. Homology models of both N. viridula receptor isoforms provide further insight into the bisacylhydrazine- and ecdysteroid-binding properties of these receptors, including their similar affinity for 20-hydroxyecdysone and the postulated pentatomomorphan moulting hormone makisterone A.
某些双酰肼类化合物，如噻嗪酮（RH5992），已被证明具有特定的昆虫选择性。还证明了它们与捕食性半翅目昆虫（用作生物防治剂）的相容性。然而，这些蜕皮激素激动剂在半翅目昆虫中的分子作用模式，更不用说在农业上重要的害虫，如绿盲蝽，尚未得到探索。
通过二维凝胶分析、质谱、同源建模和双酰肼杀虫化合物（RH5992）和各种蜕皮激素的竞争性结合，表达、纯化并表征了 N. viridula 蜕皮激素受体的可变剪接配体结合区。两种剪接同工型的配体结合没有区别，相对亲和力的顺序为 muristerone A > ponasterone A > 20-羟基蜕皮酮 > inokosterone > RH5992 > α-蜕皮酮。
通过质谱验证了 N. viridula 蜕皮激素受体剪接变体的配体结合结构域中氨基酸序列的预测差异。两种剪接变体同工型对双酰肼杀虫剂 RH5992 的亲和力均大于迄今为止表征的其他半翅目蜕皮激素受体。它们对一系列蜕皮激素的亲和力也使它们与迄今为止表征的其他半翅目蜕皮激素受体区分开来。两种 N. viridula 受体同工型的同源模型进一步深入了解了这些受体的双酰肼和蜕皮激素结合特性，包括它们对 20-羟基蜕皮酮的相似亲和力和假定的五倍子形态蜕皮激素 makisterone A。
