Exploiting pathogen-induced cell death to create disease resistant plants:R01GM05

描述（由申请人提供）：本研究将在玻利维亚的Proinpa基金会与Jean Greenberg博士合作进行，作为NIH资助R 01 GM 054292的延伸。人们广泛认识到，细菌病原体可造成巨大的人类生命损失。也许，细菌病原体、植物和人类健康之间的关系的重要性还没有得到足够的重视。在发展中国家，人类健康始于有足够的营养食物供应，通常来自植物。安第斯国家（玻利维亚、秘鲁和厄瓜多尔）最重要的作物之一是马铃薯。高原地区的大多数小农以马铃薯为主要日常食物和收入来源。在玻利维亚，马铃薯作物受到由青枯雷尔氏菌（Ralstonia solanacearum，Rs）引起的细菌性枯萎病的严重影响，青枯雷尔氏菌（Ralstonia solanacearum，Rs）是最具侵略性的病原体之一，其导致马铃薯产量损失高达90%。目前，控制Rs的唯一方法是促进农业实践，最大限度地减少受感染植物的细菌传播。了解RS-马铃薯相互作用的分子基础将为创造抗病马铃薯提供重要工具。Rs的致病性主要在于被称为效应子的毒力蛋白的聚生体的作用，所述毒力蛋白是细菌通过专门的III型装置分泌的。这些蛋白质还可以作为无毒（Avr）因子来诱导防御反应，所述防御反应激活具有同源抗性（R）基因的植物的抗病性。已经记录了三例来自Rs的Avr蛋白的病例（5; 12; 33）。植物对病原体分泌的Avr蛋白的常见防御反应是由R基因的特异性作用介导的，并导致产生抗微生物环境和局部程序性细胞死亡。我们有兴趣在确定Rs Avr细胞死亡效应，激活防御反应，在马铃薯和定义可能的植物防御分子与这些效应相互作用。从长远来看，该项目将扩大植物育种者的选择范围，并为植物基因工程提供工具，以实现更持久的抗性。我们以前做了一个大的收集效应器从玻利维亚的Rs株代表最积极的Rs亚组（系统型2，种族3，生物型2）。这些效应物中的许多足以在抗性但不可食用的马铃薯品种中引起细胞死亡，其可用于发现可转移到其他可食用品种的抗性性状。在这里，我们建议确定哪些细胞死亡效应子具有防御诱导（Avr）特性。对于真正的Avr效应子的子集，我们将确定它们在植物细胞中的亚细胞定位。最后，我们将表征Avr效应子与潜在宿主靶蛋白的相互作用。这项工作将有助于控制在美国被认为是生物恐怖威胁的2型3号生理小种生物变种2 Rs菌株。公共卫生相关性：由青枯雷尔氏菌引起的细菌性枯萎病影响玻利维亚农业最重要的作物之一马铃薯。为了创造更持久和有效的抗性植物，我们将鉴定防御反应诱导效应子。

DESCRIPTION (provided by applicant): This research will be done primary in Bolivia at the Proinpa Foundation in collaboration with Dr. Jean Greenberg, as an extension of NIH Grant R01 GM 054292. It is widely appreciated that bacterial pathogens can cause tremendous loss of human lives. Less appreciated, perhaps, is the importance of the relationship between bacterial pathogens, plants and human health. In the developing world, the human health begins from having an adequate supply of nutritious food, usually derived from plants. One of the most important crops in Andean countries (Bolivia, Peru and Ecuador) is the potato. Most of the small farmers of the highland areas depend on potato as their main daily source of food and income. In Bolivia, the potato crop is severely affected by bacterial wilt caused by Ralstonia solanacearum (Rs), one of the most aggressive pathogens that causes up to 90% losses in potato production. Currently, the only approach to control Rs is to promote agricultural practices that minimize the dispersal of bacteria from infected plants. Understanding the molecular basis of Rs-potato interaction will provide crucial tools for creating disease resistant potatoes. The pathogenicity of Rs lies mainly in the action of consortium of virulence proteins called effectors that the bacteria secrete via a specialized type III apparatus. These proteins can also act as avirulence (Avr) factors to induce defense responses that activate disease resistance in plants harboring the cognate resistance (R) genes. Three cases of Avr proteins from Rs have been documented (5; 12; 33). A common defense response to Avr proteins secreted by pathogens in plants is mediated by the specific action of R genes and leads to the production of an antimicrobial environment and localized programmed cell death. We are interested in identifying the Rs Avr cell death effectors that activate defense responses in potato and defining the possible plant defense molecules that interact with these effectors. In the long term, this project will expand the options available to plant breeders and give tools to engineer plants genetically to achieve more durable resistance. We previously made a large collection of effectors from a Bolivian Rs strain representative of the most aggressive Rs subgroups (Phylotype 2, Race 3, Biovar 2). A number of these effectors are sufficient to elicit cell death in a resistant, but inedible potato variety that could be used to find resistance traits that could be transferred to other edible varieties. Here, we propose to determine which cell death effectors have defense-inducing (Avr) properties. For the subset of bona fide Avr effectors, we will determine their subcellular localization in plants cells. Finally we will characterize the interactions of the Avr effectors with potential host target proteins. This work will have the added benefit of contributing to the control of phylotype 2 race 3 biovar 2 Rs strains, a group considered a bioterror threat in the USA. Public Health Relevance: Bacterial wilt caused by Ralstonia solanacearum affects potato, one of the most important crop of Bolivian agriculture. To create more durable and efficient resistant plants we will identify defense-response inducing effectors.