Armet from whitefly saliva acts as an effector to suppress plant defenses by targeting tobacco cystatin

背景：Arginine rich, mutated in early stage of tumors (Armet) is a well-characterized bifunctional protein as an unfolded protein response component intracellularly and a neurotrophic factor extracellularly in mammals. 

       富含精氨酸的肿瘤早期突变（Armet）是一种具有良好特征的双功能蛋白质，在哺乳动物细胞内作为未折叠的蛋白质反应成分，在细胞外作为神经营养因子。

提出问题：Recently, a new role of Armet as an effector protein mediating insect–plant interactions has been reported, however, its molecular mechanisms underlying the regulation of plant defenses remain unclear.

       最近，有报道称Armet作为介导昆虫-植物相互作用的效应蛋白发挥了新的作用，但其调节植物防御的分子机制尚不清楚。

研究内容：We investigated the molecular mechanisms underlying whitefly secreted Armet-mediated regulation of insect-plant interaction by agrobacterium-mediated transient expression, RNA interference, electrical penetration graph, protein-protein interaction studies, virus induced gene silencing assay, phytohormone analysis and whitefly bioassays.

我们通过农杆菌介导的瞬时表达、RNA干扰、电穿透图、蛋白质-蛋白质相互作用研究、病毒诱导的基因沉默试验、植物激素分析和粉虱生物测定，研究了粉虱分泌的Armet介导的昆虫-植物相互作用调节的分子机制。

主要发现：Armet, secreted by Bemisia tabaci whitefly, is highly expressed in the primary salivary gland and is delivered into tobacco plants during feeding. Overexpression of BtArmet genein tobacco enhanced whitefly performance, while silencing BtArmet gene in whitefly interrupted whitefly feeding and suppressed whitefly performance on tobacco plants. BtArmet was shown to interact with NtCYS6, a cystatin protein essential for tobacco anti-whitefly resistance, and counteract the negative effects of NtCYS6 on whitefly.

Armet由烟粉虱（Bemisia tabaci whitefly）分泌，在初级唾液腺中高度表达，并在取食期间输送到烟草植株中。BtArmet基因在烟草中的过度表达增强了粉虱的表现，而在粉虱中沉默BtArmet基因会中断粉虱的取食并抑制粉虱在烟草植株上的表现。BtArmet被证明与NtCYS6相互作用，NtCYS6是烟草抗粉虱抗性所必需的胱抑素蛋白，并抵消NtCYS6对粉虱的负面影响.
结论：These results indicate that BtArmet is a salivary effector and acts to promote whitefly performance on tobacco plants through binding to a tobacco cystatin NtCYS6. Our findings provide novel insight into whitefly-plant interactions.

这些结果表明，BtArmet是一种唾液效应器，通过与烟草胱蛋白酶抑制剂NtCYS6结合，在烟草植株上促进粉虱的生长。我们的发现为粉虱与植物的相互作用提供了新的见解。

通讯作者: 王晓伟 浙江大学农业与生物技术学院教授

连接：https://nph.onlinelibrary.wiley.com/doi/10.1111/nph.18063

Journal: New Phytologist

Published date: March 03, 2022