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。该项目专注于一组细菌，称为红球菌。大多数细菌对植物没有致病作用，并与有益的作用有关，如促进植物生长和保护它们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，将它们转化为致病物质。因此，这些质粒上的基因对这些细菌致病至关重要，这种疾病通常与毁容生长有关。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是如何发挥作用并操纵细菌基因组来致病的，该项目将提供帮助美国种植者降低疾病风险的策略。作为该项目的一部分，将有两个外联部分，旨在解决代表人数不足的学生更多参与的目标。将为高中生举办生物夏令营，让他们学习科学过程，并给他们一次大学体验。将为本科生提供长期的、有指导的研究机会，帮助他们为科学生涯做准备。病毒质粒是将红球菌转化为植物病原体的必要条件和充分条件。已鉴定出两个必需的质粒基因座。FasR基因座编码一个转录因子。Fas基因编码与细胞分裂素代谢有关的蛋白质。FasR的调控尚不清楚。相比之下，一个长期存在的假说表明，被称为植物生长促进激素的细胞分裂素是由微生物合成的，以直接操纵植物宿主。研究将测试另一种假设，即质粒编码的基因和细胞分裂素共同选择并重新编程染色体基因以产生毒力。三个目的是确定基因在发病机制中的必要性和充分性，了解毒力基因是如何调控的，以及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整个转录组学以及蛋白质组学研究，以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，从而导致植物患病。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.