Reprogramming of tRNAs in virulence of plant pathogenic Rhodococcus

这个项目的首要目标是了解细菌对植物致病的机制。这个项目的重点是一种叫做红球菌的细菌。大多数细菌对植物没有致病性，而是有有益的作用，如促进植物生长和保护植物免受其他病原体引起的疾病。然而，红球菌可以获得额外的DNA，称为质粒，将其转化为致病性。因此，这些质粒上的基因对这些细菌引起疾病至关重要，而疾病通常与畸形生长有关。这种疾病给美国农业造成了数百万美元的损失。通过了解质粒携带的基因如何发挥作用并操纵细菌基因组导致疾病，该项目将为帮助美国种植者减轻疾病风险的策略提供信息。作为项目的一部分，将有两个外联部分，旨在解决增加代表性不足的学生参与的目标。夏季生物夏令营将提供给高中生，让他们学习科学过程，并让他们体验大学生活。将为本科生提供长期的指导研究机会，帮助他们为科学事业做好准备。毒力质粒是将红球菌转变为植物病原体的必要条件和充分条件。两个质粒位点已被确定为必要的。fasR基因座编码一个转录因子。fas基因座编码与细胞分裂素代谢有关的蛋白质。fasR的调控机制尚不清楚。相反，一个长期存在的假设认为，细胞分裂素是由微生物合成的，直接操纵植物宿主。细胞分裂素是最著名的植物生长促进激素。研究将测试另一种假设，即质粒编码的基因和细胞分裂素对染色体基因的毒力进行了调节和重编程。研究的三个目的是确定致病基因的必要性和充分性，了解毒力基因是如何调控的，并测试细胞分裂素在调节细菌病原体毒力中的作用。为了实现这些目标，该项目将使用分子遗传学方法和全转录组学以及蛋白质组学研究来揭示质粒携带的毒力基因如何改变染色体基因的表达模式，从而导致植物疾病。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The overarching goal of this project is to understand the mechanisms by which bacteria cause disease to plants. This project focuses on one group of bacteria, called Rhodococcus. Most bacteria are not pathogenic to plants and are associated with beneficial effects, such as promoting growth of plants and protecting them from disease caused by other pathogens. However, Rhodococcus can acquire extra DNA called plasmids that transition them to being pathogenic. Hence, genes on these plasmids are critical for these bacteria to cause disease, which is typically associated with disfigured growth. This disease results in millions of dollars of damage to US agriculture. By understanding how plasmid-borne genes function and manipulate the genome of the bacteria to cause disease, this project will inform on strategies to help US growers mitigate disease risks. As part of the project, there will be two outreach components designed to address goals of increasing participation by underrepresented students. Summer biology camps will be delivered to high school students to learn the scientific process and give them a college experience. Long-term, mentored research opportunities will be provided to undergraduate students to help prepare them for careers in the sciences.Virulence plasmids are necessary and sufficient to transition Rhodococcus to being a pathogen of plants. Two plasmid loci have been identified as necessary. The fasR locus encodes a transcription factor. The fas locus encodes proteins implicated in the metabolism of cytokinins. The regulon of fasR remains unknown. In contrast, a long-standing hypothesis suggests that cytokinins, which are best known as plant growth promoting hormones, are synthesized by microbes to directly manipulate plant hosts. Research will test an alternative hypothesis that plasmid-encoded genes and cytokinins coopt and reprogram chromosomal genes for virulence. Three aims are designed to determine the necessity and sufficiency of genes in pathogenesis, understand how virulence genes are regulated, and test the role of cytokinins in regulating virulence of bacterial pathogens. To accomplish these aims, the project will use molecular genetic approaches and whole transcriptomics as well as proteomics studies to uncover how plasmid borne virulence genes alter the expression patterns of chromosomal genes to cause disease to plants.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.