INTERACTIONS BETWEEN AGROBACTERIUM AND HOST PLANTS

农杆菌和寄主植物之间的相互作用

• 批准号: 6363243
• 负责人: Stephen C. Winans
• 金额: $ 31.07万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-07-01 至 2003-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6363243
• 关键词: Agrobacterium tumefaciens; Arabidopsis; DNA directed RNA polymerase; DNA footprinting; Escherichia coli; bacterial genetics; bacterial proteins; endopeptidases; fluorescence microscopy; gel mobility shift assay; gene expression; genetic regulation; genetic transcription; green fluorescent proteins; host organism interaction; pheromone; proteolysis; receptor; receptor binding

We propose to study the two-way exchange of chemical signals between the pathogenic microbe Agrobacterium tumefaciens and its plant hosts. This organism causes crown gall tumors in higher plants by transferring a segment of oncogenic DNA into the plant genome. Our primary focus is on the transcriptional regulation of genes in response to chemical signals released from hosts. Virtually all pathogens induce pathogenesis-related genes in response to host-released signals, and A. tumefaciens is a valuable model for studying this phenomenon. At the outset of infection, wound-released compounds act through three proteins (the transmembrane sensory protein kinase VirA, the response regulator VirG, and the periplasmic sugar binding protein ChvE) to activate transcription of the vir regulon. Later, a compound called octopine acts through the OccR protein (a LysR-type protein) to induce other genes, including the conjugation regulator TraR. TraR and TraI are members of the LuxR/LuxI family of quorum-sensing proteins, and induce tra genes only at high donor cell densities. At least one other plant pathogen and one animal pathogen (Pseudomonas aeruginosa) use homologous proteins to regulate pathogenesis- related genes. A second focus of our work is to study the transfer of T- DNA to the host. We will determine whether three previously uncharacterized genes in the vir region are required for virulence, and whether they are regulated by VirG. We will also study a tra operon from a different plasmid as a model for the eleven genes of the virB operon, as the two operons are closely homologous. Understanding these conjugation- like processes may lead to new ways to prevent the transfer of antibiotic resistance genes and toxin determinants between bacteria. More generally this phenomenon is an example of export of macromolecular complexes from cells and transport of these complexes between cells.

我们建议研究之间的化学信号的双向交换 致病微生物菌菌及其植物宿主。这 通过转移A 致癌性DNA片段进入植物基因组。我们的主要重点是 基因对化学信号的转录调节 从主机发行。几乎所有病原体诱导了与发病机理有关的 响应宿主发行的信号的基因，而曲霉曲霉是一个 研究这种现象的宝贵模型。在感染开始时， 伤口释放的化合物通过三种蛋白（跨膜 感觉蛋白激酶ViRA，响应调节剂VIRG和 周质糖结合蛋白CHVE）激活 Vir Regulon。后来，一种称为章鱼的化合物通过OCCR作用 蛋白质（一种LYSR型蛋白）诱导其他基因，包括 共轭调节器Trar。 Trar和Trai是Luxr/Luxi的成员 群体感应蛋白家族，仅在高供体处诱导TRA基因 细胞密度。至少另一种植物病原体和一种动物病原体 （铜绿假单胞菌）使用同源蛋白来调节发病机理 - 相关基因。我们工作的第二个重点是研究t-的转移 DNA到主机。我们将确定以前三个 毒力需要毒力中的病毒区域中的未表征基因，并且 它们是否受VIRG监管。我们还将从 一个不同的质粒作为virb操纵子的11个基因的模型，作为 两个操纵子非常同源。了解这些共轭 - 像过程一样，可能导致防止抗生素转移的新方法 抗性基因和细菌之间的毒素决定因素。更普遍 这种现象是从大分子复合物出口的一个例子 细胞和这些复合物在细胞之间的运输。