Modulation of host defense responses by Agrobacterium tumefaciens Type VI secretion system

该奖项由2009年美国复苏和再投资法案(公法111-5)资助。细菌经常通过分泌系统传递蛋白质或DNA因子，从而操纵正常的宿主细胞功能和/或颠覆宿主防御，从而在植物或动物中引起疾病。土壤细菌根癌农杆菌将蛋白质和DNA输送到多种植物中，导致受感染植物发生肿瘤或“植物癌”。研究人员最近发现，缺少一种这样的分泌系统--VI型分泌系统(T6SS)的农杆菌，与正常细菌相比，其致癌能力受到了损害。该项目的目标是确定通过农杆菌T6SS传递的因子如何改变或抑制宿主植物？防御。研究人员将测量植物产生的特定防御化合物的数量，并将监测植物对正常或T6SS缺乏细菌的防御相关基因的反应程度。这一结果将揭示植物如何保护自己免受植物癌症等疾病侵袭的新信息。由于最近在各种各样的其他细菌中也发现了类似的T6SS，包括几种会导致人类严重疾病的细菌，这些发现很可能也与这些其他感染性病原体有关。除了在引起植物病害方面的作用外，农杆菌还被广泛用于将新基因导入植物中，但由于一些植物，包括许多重要的经济作物，是糟糕的宿主，其用途受到限制。该项目将对使一些植物物种能够更好地抵抗农杆菌的因素产生新的见解。该项目完全融合了研究和教育，因为实验将主要由本科生进行，从而为他们提供在尖端研究中发挥领导作用的机会。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Bacteria frequently cause disease in plants or animals by using secretion systems to deliver protein or DNA factors that manipulate normal host cell functions and/or subvert host defenses. The soil bacterium Agrobacterium tumefaciens transports both protein and DNA into a variety of plants, resulting in tumors or "plant cancer" on infected plants. The investigators recently discovered that Agrobacteria lacking one such secretion system, the Type VI Secretion System (T6SS), are compromised in their ability to cause tumors compared to normal bacteria. The goal of this project is to determine how the factors delivered through the Agrobacterium T6SS alter or dampen the host plants? defenses. The investigators will measure the amount of specific defense compounds produced by the plant, and will monitor the extent to which the plants turn on defense-related genes in response to the normal or the T6SS-deficient bacteria. The results will reveal new information about how plants protect themselves from diseases such as plant cancer. Because similar T6SS have recently been found in a wide variety of other bacteria, including several that cause serious diseases in humans, the findings may well have relevance to these other infectious agents as well. In addition to its role in causing plant disease, Agrobacterium is widely used to introduce new genes into plants, but its utility is limited by the fact that some plants, including many economically important grain crops, are poor hosts. This project will yield new insights into the factors that make some plant species better able to resist Agrobacteria. The project fully integrates research and education, in that the experiments will be performed primarily by undergraduate students, thereby providing them with the opportunity to take a leadership role in cutting-edge research.