Insect gustatory receptors play crucial roles in multiple physiological behaviours. Although the alternative splicing of some gustatory receptors has been observed in insect species, differences in their ligands and functions have rarely been reported. Here, we cloned NlGr10a and NlGr10b, two alternative splicing variants of a sugar gustatory receptor gene in the brown planthopper (BPH), Nilaparvata lugens (Stål), and found that their ligands were different by calcium imaging assay. The ligands of NlGr10a were fructose and cellobiose, and the ligand of NlGr10b was arabinose. Subsequently, the RNAi results showed that knockdown of both splicing variants decreased the number of eggs laid by BPH females, and the egg hatching rate after knockdown of NlGr10a was significantly lower than that after knockdown of NlGr10b. Furthermore, NlGr10a promoted the fecundity of BPH through the AMPK- and AKT-NlVg/NlVgR signalling pathways, whereas NlGr10b promoted the fecundity only through the AMPK- and AKT-NlVg signalling pathways. These findings broaden our understanding of the difference in the ligands and functions of alternative splicing variants of gustatory receptors in insects.

中文翻译：

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糖味受体的两个选择性剪​​接变体通过褐飞虱Nilaparvata lugens中的不同信号传导途径调节繁殖力。

昆虫味觉受体在多种生理行为中起关键作用。尽管在昆虫物种中已观察到一些味觉受体的可变剪接，但很少报道其配体和功能的差异。在这里，我们克隆了NlGr10a和NlGr10b，这是褐飞虱（BPH）中糖味受体基因的两个可选剪接变体，Nilaparvata lugens（Stål），并通过钙成像分析发现它们的配体不同。NlGr10a的配体是果糖和纤维二糖，NlGr10b的配体是阿拉伯糖。随后，RNAi结果显示敲除两个剪接变体减少了BPH雌性产卵的数量，敲除NlGr10a后的卵孵化率显着低于敲除NlGr10b后的卵孵化率。此外，NlGr10a通过AMPK-和AKT-NlVg / NlVgR信号通路促进了BPH的繁殖力，而NlGr10b仅通过AMPK-和AKT-NlVg信号通路促进了繁殖力。这些发现拓宽了我们对昆虫味觉受体的可变剪接变体的配体和功能差异的理解。