Interplay of pathogens, microRNAs, and regulation of resistance gene transcript abundance for rapid evolutionary responses in plants.

病原体、microRNA 的相互作用以及抗性基因转录本丰度的调节对植物快速进化反应的影响。

• 批准号: 274476172
• 负责人: Professorin Dr. Laura Rose
• 金额: --
• 依托单位: Institut Populationsgenetik
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/274476172?language=en
• 关键词: Interplay; pathogens; microRNAs; regulation; resistance

Pathogens and hosts can differ by orders of magnitude in their generation time and population sizes. This difference presents a challenge for hosts to match and counter the rapid evolution and adaptation endowed by the shorter generation times (and larger population sizes) of pathogens. We seek to investigate by which means (i.e. which evolutionary genetic changes) plant species can match the rapid evolutionary potential of their microbial pathogen species. The focus of our work is the host-pathogen system involving wild tomato species and the oomycete pathogen, Phytophthora infestans. We will investigate the interplay of microRNA (miR) genes, NBS-LRR resistance genes, and pathogen resistance across multiple wild and domesticated tomato species. A small family of miR genes that negatively regulates transcript abundance of NBS-LRR genes has recently been discovered in tomato. The up-regulation of these miR genes leads to the downregulation of NBS-LRRs resistance genes, and vice-versa. Therefore, miRNA abundance is likely tied to levels of disease resistance in plants. Post-transcriptional control of R-genes may allow the plants to mount a more rapid defense response to pathogen attack and thus may be an adaptation deployed in plants to match the evolutionary potential of their pathogens. However, post-transcriptional control of R-genes can also be hijacked by pathogens to suppress defense responses. We predict that presence of pathogens in plants does affect the miR transcript abundance and subsequently the R-protein abundance. At the one extreme, pathogen up regulation of miR genes or secretion of miR molecular mimics would down regulate R-gene abundance. This would be viewed as an adaptation on the part of the pathogen. Alternatively, down-regulation by the pathogen of these miR genes would lead to up-regulation of R-genes. In this case, resistance would be activated and the plant would have the advantage. Either scenarios give us insight into the complex reciprocal evolutionary genetic changes that have taken place between these species. In this research initiative, we would like to investigate the post-transcriptional regulation of R-genes through members of a small miR gene family in the presence of pathogen infection. We will conduct controlled inoculations of eight different tomato species using four different pathogen genotypes. The level of pathogen spread and host resistance will be determined. Simultaneously we will assay the abundance of the primary and mature transcripts of seven miR genes during the infection. We will also assay the transcript abundance of eight putative P. infestans resistance genes, targeted by these miR transcripts. Through multivariate statistical analyses, we will be able to identify the which miR genes and which R-genes are up- or down-regulated during pathogen infection. These genes will be subjected to further investigation for functional, in planta, validation.

病原体和宿主在世代时间和种群大小上可能存在数量级的差异。这种差异给寄主带来了一个挑战，即如何匹配和对抗病原体较短的世代时间(和较大的种群规模)带来的快速进化和适应。我们试图研究植物物种可以通过哪些方式(即进化的遗传变化)来匹配它们的微生物病原体物种的快速进化潜力。我们的工作重点是涉及野生番茄和卵菌病原菌致病疫霉的寄主-病原系统。我们将研究microRNA(MiR)基因、NBS-LRR抗性基因和多种野生和驯化番茄品种对病原菌抗性的相互作用。最近在番茄中发现了一个小的miR基因家族，它负向调节NBS-LRR基因的转录丰度。这些miR基因的上调导致NBS-LRRS抗性基因的下调，反之亦然。因此，miRNA的丰度可能与植物的抗病水平有关。对R基因的转录后调控可能使植物对病原体攻击产生更快的防御反应，从而可能是植物对病原体进化潜力的一种适应。然而，R基因的转录后控制也可以被病原体劫持以抑制防御反应。我们预测，植物中病原体的存在确实会影响miR转录本的丰度，进而影响R蛋白的丰度。在一种极端情况下，病原菌上调miR基因或分泌miR分子模拟物将下调R基因的丰度。这将被视为病原体的一种适应。或者，病原体下调这些miR基因将导致R基因上调。在这种情况下，阻力将被激活，植物将拥有优势。这两种情况都让我们洞察到这些物种之间发生的复杂的相互进化的遗传变化。在这项研究中，我们想要研究在病原体感染存在的情况下，通过一个小的miR基因家族成员对R基因转录后的调节。我们将使用四种不同的病原菌基因对八个不同的番茄品种进行控制接种。病原体的传播水平和寄主抗药性将被确定。同时，我们将检测感染期间七个miR基因的初级和成熟转录本的丰度。我们还将分析这些miR转录本靶向的八个可能的致病疫霉抗性基因的转录丰度。通过多元统计分析，我们将能够识别哪些miR基因和哪些R基因在病原体感染过程中上调或下调。这些基因将接受进一步的功能研究，以进行植物验证。