Interactions Between Agrobacterium and Host Plants

描述(申请人提供)：本实验室的目标是继续发展农杆菌-植物病理系统，使其成为宿主-微生物相互作用和信息素介导的细菌交流的领先模型。在过去的15年里，通过可扩散的化学信号进行的细胞间通信已被认为是许多细菌的重要特性，特别是那些与植物、动物或人类宿主相关的细菌。在这些信号中，酰基高丝氨酸内酯(AHLS)在变形杆菌中尤其广泛。AHL通常由与费氏弧菌Lux1蛋白相似的蛋白质合成，并由与V.ficsheri LuxR蛋白相似的转录因子检测。我的实验室专注于几种LuxR型蛋白质的遗传和生化研究。其中，根癌农杆菌的TRAL和TRAR系统调节大的致癌质粒的接合和营养复制所需的基因。盲肠伯克霍尔德氏菌的CEP1和CEPR调控该细菌多条染色体和质粒上的多个基因，而小肠结肠炎耶尔森菌的Yen1和YenR调控包括Yens在内的未知数量的基因，似乎编码一个小的调控RNA。我们将继续测试这一假设，即TRIR和CEPR需要AHL才能正确折叠，并且必须在它们自己在核糖体上合成的过程中结合这种信息素。我们还将研究TRAR的一个或多个激活区域如何与RNA聚合酶相互作用。我们将识别CEPR和YenR激活的靶基因。YenR的不同寻常之处在于它作为一种脱辅酶蛋白具有活性，其活性被AHLS抑制。我们将尝试在体外重建这种抑制作用。最后，我们将测试YENS编码一个小的非编码RNA的想法，并确定该SRNA是否通过形成异源双链来调节靶mRNAs的稳定性。YenR和Yens的直接靶标将被确定和评估它们在小肠结肠炎耶尔森菌和鼠疫耶尔森菌的生物学和生态学中的作用。

DESCRIPTION (provided by applicant): The goal of this laboratory is continue to the develop the Agrobacterium-plant pathosystem as a leading model for host-microbe interactions and for pheromone-mediated bacterial communication. In the past 15 years, cell-cell communication via diffusible chemical signals has come to be appreciated as an important property of many bacteria, especially those associated with plant, animal, or human hosts. Among these signals, acyl-homoserine lactones (AHLs) are especially widespread among the proteobacteria. AHLs are generally synthesized by proteins resembling the Luxl protein of Vibrio fischeri, and detected by transcription factors resembling the V. ficsheri LuxR protein. My lab focuses on genetic and biochemical studies of several LuxR-type proteins. One of these systems, Tral and TraR of Agrobacterium tumefaciens regulate genes required for the conjugation and vegetative replication of a large tumor-inducing plasmid. Cepl and CepR of Burkholderia cenocepacia regulate many genes on several chromosomes and plasmid of this bacterium, while Yenl and YenR of Yersinia enterocolitica regulate an unknown number of genes, including yenS, which appears to encode a small regulatory RNA. We will continue to test the hypothesis that TraR and CepR require AHL for correct folding, and must bind this pheromone during their own synthesis on ribosomes. We will also study how the activating region or regions of TraR interact with RNA polymerase. We will identify target genes activated by CepR and YenR. YenR is unusual in that it is active as an apo-protein and its activity is inhibited by AHLs. We will try to reconstitute this inhibition in vitro. Finally, we will test the idea that yenS encodes a small non-coding RNA and determine whether this sRNA regulates the stability of target mRNAs by forming heteroduplexes. Direct targets of YenR and YenS will be identified and assessed for their roles in the biology and ecology of Y. enterocolitica and Y. pestis.