EAGER: Striga Virulence Effectors: Keys to Halting Parasitic Witchweeds

被子植物寄生虫是农田中的一种持久性有害生物，严重制约着农作物的生产。独脚金属的成员“独脚金”特别具有破坏性，因为它们的主要宿主包括全世界的主食谷物（玉米、高粱、水稻和小米）和豆类。寄生杂草和独脚金物种如何识别它们的潜在宿主并克服先天防御系统尚不清楚。利用豇豆（豇豆），一种重要的粮食和饲料豆类，与独脚金的相互作用，该项目旨在确定寄生虫衍生的效应和毒力蛋白，进入宿主细胞，特别是改变其结构和功能，并在各个水平上抑制防御反应机制，使感染和寄生虫入侵发生。新的，在植物中的功能筛选将被用来确定候选效应从独脚金是直接或间接识别的种族特异性抗性蛋白在豇豆导致激活过敏反应在感染点和相关的下游防御反应。这些功能筛选通过相容和不相容宿主-寄生虫关联中的比较转录组测序以及旨在通过种族特异性基因表达特征识别候选毒力效应子的计算机模拟分析来补充。该项目的成果将提供新的见解的机制，寄生被子植物识别和寄生其主机和主机如何阻止这种攻击。寄生植物对作物生产力的负面影响在全球范围内每年都在增加，随着种子资源在全球范围内的流动，它们对国内农业的影响也越来越大。这项工作的成果将直接有助于制定战略，以提高作物安全性，提供目标操纵作物的害虫抗性反应。此外，这些研究为非洲大陆的美国学生提供了新的教育，研究和培训机会。

Parasitic angiosperms are noxious and persistent pests in farmers' fields and serious constraints to crop productivity. The "witchweeds", members of the genus Striga, are particularly devastating since their primary hosts include the major cereals (maize, sorghum, rice and millet) and grain legumes that are dietary staples worldwide. How parasitic weeds and Striga species in particular recognize their potential hosts and overcome the innate defense systems are not known. Using the interaction of cowpea (Vigna unguiculata), an important food and forage legume, with Striga gesnerioides, this project seeks to identify parasite-derived effectors and virulence proteins that enter host cells, specifically altering their structure and function and suppressing the defense response mechanism at various levels, enabling infection and parasite ingress to occur. Novel, in planta functional screens will be used to identify candidate effectors from Striga that are directly or indirectly recognized by race-specific resistance proteins in cowpea leading to activation of a hypersensitive response at the point of infection and associated downstream defense responses. These functional screens are complemented by comparative transcriptome sequencing in compatible and incompatible host-parasite association and in silico analysis aimed at identifying candidate virulence effectors through race-specific gene expression signatures. The outcomes of this project will provide novel insights into the mechanisms by which parasitic angiosperms identify and parasitize their hosts and how hosts block such attack. The negative impact of parasitic plants on crop productivity increases globally each year and their potential for affecting domestic agriculture looms larger as the movement of seed resources expands globally. The outcomes of this work will contribute directly to the development of strategies to improve crop security by providing targets for manipulating pest resistance responses of crop plants. In addition these studies provide new educational, research, and training opportunities for US students on the African continent.