Institute of Insect Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China.
Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insect Pests, Zhejiang University, Hangzhou, China.
PLoS Pathog. 2021 Mar 1;17(3):e1009365. doi: 10.1371/journal.ppat.1009365. eCollection 2021 Mar.
Parasites alter host energy homeostasis for their own development, but the mechanisms underlying this phenomenon remain largely unknown. Here, we show that Cotesia vestalis, an endoparasitic wasp of Plutella xylostella larvae, stimulates a reduction of host lipid levels. This process requires excess secretion of P. xylostella tachykinin (PxTK) peptides from enteroendocrine cells (EEs) in the midgut of the parasitized host larvae. We found that parasitization upregulates PxTK signaling to suppress lipogenesis in midgut enterocytes (ECs) in a non-cell-autonomous manner, and the reduced host lipid level benefits the development of wasp offspring and their subsequent parasitic ability. We further found that a C. vestalis bracovirus (CvBV) gene, CvBV 9-2, is responsible for PxTK induction, which in turn reduces the systemic lipid level of the host. Taken together, these findings illustrate a novel mechanism for parasite manipulation of host energy homeostasis by a symbiotic bracovirus gene to promote the development and increase the parasitic efficiency of an agriculturally important wasp species.
寄生虫为了自身的发育而改变宿主的能量稳态，但这一现象的机制在很大程度上仍然未知。在这里，我们表明，小菜蛾绒茧蜂，小菜蛾幼虫的一种内寄生蜂，会刺激宿主脂质水平的降低。这个过程需要寄生的宿主幼虫中肠的肠内分泌细胞（EEs）过量分泌小菜蛾速激肽（PxTK）肽。我们发现，寄生以上调 PxTK 信号以非细胞自主的方式抑制中肠肠细胞（ECs）中的脂肪生成，而降低的宿主脂质水平有利于蜂后代的发育及其随后的寄生能力。我们进一步发现，小菜蛾绒茧蜂的一种共生质病毒（CvBV）基因 CvBV9-2 负责诱导 PxTK，进而降低宿主的系统脂质水平。总的来说，这些发现说明了寄生虫通过共生质病毒基因操纵宿主能量稳态的一种新机制，以促进一种农业上重要的寄生蜂物种的发育和增加其寄生效率。
