The LC-MS results of the DBC and LOSC.

Saliva plays important roles in insect feeding, but its roles in insect reproduction were rarely reported. Here we reported that the knockdown of a salivary gland-specific gene NlG14 disrupted the reproduction through inhibiting the ovulation of the brown planthopper (BPH), Nilaparvata lugens (Stål), one of the most devastating rice pests in Asia. NlG14 knockdown caused the displacement of the lateral oviduct secreted components (LOSC), leading to the ovulation disorder and the accumulation of mature eggs in the ovary. The RNAi-treated females laid much less eggs than their control counterparts, though they had the similar oviposition behavior on rice stems as controls. NlG14 protein was not secreted into the hemolymph, indicating an indirect effect of NlG14 knockdown on BPH reproduction. NlG14 knockdown caused the malformation of A-follicle of the principal gland and affected the underlying endocrine mechanism of salivary glands. NlG14 reduction might promote the secretion of insulin-like peptides NlILP1 and NlILP3 from the brain, which up-regulated the expression of Nllaminin gene and then caused the abnormal contraction of lateral oviduct muscle. Another explanation was NlG14 reduction disrupted the ecdysone biosynthesis and action through the insulin-PI3K-Akt signaling in ovary. Altogether, this study indicated that the salivary gland specific protein NlG14 indirectly mediated BPH ovulation process, which established a connexon in function between insect salivary gland and ovary.唾液在昆虫取食过程中发挥重要作用，但其在昆虫生殖中的功能却鲜有报道。本研究发现，唾液腺特异性基因NlG14的敲低会通过抑制褐飞虱（Nilaparvata lugens Stål，以下简称BPH）的排卵过程破坏其生殖功能，而褐飞虱是亚洲地区危害最为严重的水稻害虫之一。敲低NlG14会导致侧输卵管分泌组分（lateral oviduct secreted components, LOSC）发生位移，进而引发排卵紊乱与卵巢内成熟卵的蓄积。尽管经RNA干扰（RNA interference, RNAi）处理的雌虫在水稻茎秆上的产卵行为与对照组无明显差异，但其产卵量远低于对照个体。NlG14蛋白并不会被分泌至血淋巴中，这表明NlG14敲低对褐飞虱生殖的影响为间接作用。敲低NlG14会导致主腺A滤泡（A-follicle of the principal gland）出现畸形，并影响唾液腺的内在内分泌调控机制。NlG14表达量降低可能会促进大脑分泌类胰岛素肽NlILP1与NlILP3，这两种肽会上调Nllaminin基因的表达，进而引发侧输卵管肌层的异常收缩。另一潜在机制为：NlG14表达量降低会通过卵巢内的胰岛素-PI3K-Akt信号通路（insulin-PI3K-Akt signaling）破坏蜕皮激素的生物合成及其信号作用。综上，本研究证实唾液腺特异性蛋白NlG14可间接介导褐飞虱的排卵过程，从而在昆虫唾液腺与卵巢之间建立了功能关联。