Interactions Between Agrobacterium and Host Plants

描述（由申请人提供）：该实验室的目标是继续发展农杆菌-植物病理系统，作为宿主-微生物相互作用和信息素介导的细菌交流的主要模型。在过去的15年里，细胞间通过扩散的化学信号进行通信已经被认为是许多细菌的重要特性，特别是那些与植物、动物或人类宿主有关的细菌。在这些信号中，酰基同丝氨酸内酯（ahl）在变形菌中尤为普遍。ahl一般由类似于费氏弧菌Luxl蛋白的蛋白质合成，并由类似于费氏弧菌LuxR蛋白的转录因子检测。我的实验室主要研究几种luxr型蛋白的遗传和生化研究。其中一个系统是农杆菌的Tral和TraR，它们调节了一个大的肿瘤诱导质粒的结合和无性复制所需的基因。新绿伯克氏菌的Cepl和CepR调控该菌多条染色体和质粒上的许多基因，而小肠结肠炎耶尔森菌的Yenl和YenR调控未知数量的基因，包括yenS，其似乎编码一种小的调控RNA。我们将继续测试TraR和CepR需要AHL才能正确折叠的假设，并且在它们自己在核糖体上合成时必须结合该信息素。我们还将研究TraR的激活区如何与RNA聚合酶相互作用。我们将鉴定由CepR和yanr激活的靶基因。不同寻常的是，yanr作为载脂蛋白具有活性，其活性被ahl抑制。我们将尝试在体外重建这种抑制作用。最后，我们将验证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工来调节目标mrna的稳定性。将确定并评估YenR和YenS在小肠结肠炎耶氏菌和鼠疫耶氏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.