The host signal landscape recognized by Agrobacterium tumefaciens

根癌农杆菌在大多数温带和热带气候的土壤中被发现是自由生活的细菌。这种细菌的某些菌株可以感染各种各样的植物，并导致它们产生肿瘤。这是细菌中各种分子过程激活的结果，这些分子过程为细菌提供了诱发植物肿瘤的能力。有趣的是，一些植物物种似乎不会通过形成肿瘤来对细菌做出反应，而在确实形成肿瘤的植物中，某些组织类型似乎更容易受到影响。研究人员正在确定细菌如何识别它们在植物上--或者更准确地说，是特定的植物组织。在与植物组织密切接触后，细菌识别植物产生的不同化学物质，包括酚类衍生物和某些糖。这两种类型的分子都需要诱导导致肿瘤发展所需的细菌产物的合成。有趣的是，这些分子在植物周围的分布并不均匀。研究人员已经设计了一系列实验，使他们能够绘制出植物内部信号的分布(从而确定“信号景观”)。通过这些研究，他们将能够确定植物中对细菌产生肿瘤的区域是否是植物中唯一产生适当信号的区域。例如，这可能导致识别出即使在细菌被“人工激活”的情况下也不会产生肿瘤的组织，从而理解这些组织是如何“防御”细菌引起的肿瘤的。一个科学家团队将指导该项目，他们的专业领域包括化学、生物化学、植物病理学、分子生物学和微生物学。这为博士后、研究生和本科生提供了强有力的跨学科培养环境。计划中的实验将为在我们实验室工作的三到六名本科生提供项目。学生将获得在分子生物学、生化和细胞培养技术方面的实践经验，并有机会向他们的同龄人展示他们的工作。此外，这两个私人投资机构都广泛参与了科学教育的替代办法，并可将拟议工作的许多方面纳入这些项目。

Agrobacterium tumefaciens is found as free-living bacteria in the soils of most temperate and tropical climates. Certain strains of the bacterium can infect a wide variety of plants and cause them to develop tumors. This occurs as a result of the activation of a variety of molecular processes in the bacterium that provide it with the capacity to induce plant tumors. Interestingly, some plant species do not appear to respond to the bacteria by forming tumors and in plants that do form tumors, certain tissue types seem significantly more susceptible. The investigators are determining how the bacteria recognize that they are on a plant - or more precisely in particular plant tissues. After coming into close proximity with plant tissues the bacterium recognizes different chemicals produced by the plant, including phenolic derivatives and certain sugars. Both types of molecules are required to induce the synthesis of bacterial products required to cause tumors to develop. Intriguingly, the distribution of these molecules is not uniform around the plant. The investigators have designed a series of experiments that will allow them to map the distribution of the signals within the plant (thereby determining the 'signal landscape'). Through these studies they will then be able to determine whether regions of the plant that make tumors in response to the bacteria are the only regions of the plant that make the appropriate signals. This, for example, could lead to the identification of tissues that don't make tumors even when the bacteria are 'artificially activated' and thereby lead to an understanding of how these tissues 'defend' themselves against the tumor causing actions of the bacterium. A team of scientists whose areas of expertise comprise chemistry, biochemistry, plant pathology, molecular biology, and microbiology will direct the project. This provides a strong interdisciplinary training environment for postdoctoral, graduate and undergraduate students. The planned experiments will provide projects for three to six undergraduate students who work in our laboratories. Students will get 'hands on' experience in molecular biological, biochemical, and cell culture techniques and the opportunity to present their work to their peers. Moreover, both PIs have been extensively involved in alternative approaches to science education and can incorporate many aspects of the proposed work into these projects.