Elucidating in planta target genes of Ralstonia solanacearum TALE-like proteins

阐明植物中青枯菌 TALE 样蛋白的靶基因

• 批准号: 262924427
• 负责人: Professor Dr. Thomas Lahaye
• 金额: --
• 依托单位: Abteilung für Allgemeine Genetik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2016-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/262924427?language=en
• 关键词: Elucidating; planta; target; genes; Ralstonia

Ralstonia solanacearum, the causal agent of bacterial wilt disease, is a quarantine organism in the USA and EU that ranks among the most devastating microbial pathogens in crop plants. We aim to study the interaction between R. solanacearum and its host plants at the molecular level and anticipate that our findings will enable us, in the long run, to develop effective countermeasures against this devastating pathogen. The effector proteins injected by bacterial pathogens into host cells either promote disease or trigger plant immunity. They are thus key determinants for the outcome of plant-microbe interactions. In the framework of this proposal we will study RipTALs, one class of effectors that are widespread in R. solanacearum and that share homology with Transcription Activator Like Effectors (TALEs) from the bacterial genus Xanthomonas.The TALE code describes the correlation of defined amino acids in a given TALE DNA binding domain with specific DNA bases in its effector binding element (EBE). This allows in silico prediction of EBEs for TALEs of known sequence. In preliminary studies we showed that, like for TALEs, RipTAL EBEs can be predicted with the TALE code. Furthermore RipTALs, like TALEs are injected into host cells and are capable of transcriptionally activating promoters bearing a predicted EBE. It is thus conceivable that RipTALs, like TALEs, transcriptionally activate host genes to promote susceptibility in host plants. Given that R. solanacearum is a root pathogen, while xanthomonads typically infect aerial tissues, it is conceivable that they promote disease by activation of host susceptibility (S) genes that encode functionally distinct proteins.We aim to identify RipTAL activated host S genes that promote bacterial disease when being transcriptionally upregulated by a given RipTAL. Once host S genes have been isolated and functionally validated we want to clarify how S gene products promote R. solanacearum disease at the molecular level.R. solanacearum strains isolated from all over the world can be subdivided into four phylotypes, which correlate with their geographical origin. Notably R. solanacearum phylotypes I, II and IV contain RipTALs that differ in their N- and C-terminal regions and their predicted EBEs. Till now molecular studies of RipTALs have been conducted almost exclusively on RipTALs from phylotype I. In the framework of this proposal we aim to also characterize RipTALs from phylotype II and IV strains with the long term goal to identify and characterize corresponding host S genes and gene products.In summary we aim to identify and characterize host S genes that are activated by RipTALs from diverse R. solanacearum phylotypes. We anticipate that our findings will provide insights into the disease strategies of R. solanacearum, aiding the development of efficient countermeasures to protect crop plants.

青枯雷尔斯顿菌（Ralstonia solanacearum）是青枯病的病原体，是美国和欧盟的一种检疫生物，是农作物中最具破坏性的微生物病原体之一。我们的目标是在分子水平上研究青枯菌与其寄主植物之间的相互作用，并预计我们的研究结果将使我们能够从长远来看，制定针对这种毁灭性病原体的有效对策。细菌病原体注入宿主细胞的效应蛋白要么促进疾病，要么触发植物免疫。因此，它们是植物-微生物相互作用结果的关键决定因素。在本提案的框架中，我们将研究 RipTAL，这是青枯菌中广泛存在的一类效应子，与黄单胞菌属的转录激活子样效应子 (TALE) 具有同源性。TALE 代码描述了给定 TALE DNA 结合域中定义的氨基酸与其效应子结合元件 (EBE) 中特定 DNA 碱基的相关性。这允许在计算机上预测已知序列的 TALE 的 EBE。在初步研究中，我们表明，与 TALE 一样，可以使用 TALE 代码来预测 RipTAL EBE。此外，RipTAL 与 TALE 一样被注射到宿主细胞中，并且能够转录激活带有预测 EBE 的启动子。因此可以想象，RipTAL 与 TALE 一样，通过转录激活宿主基因，从而提高宿主植物的敏感性。鉴于青枯菌是一种根部病原体，而黄单胞菌通常感染地上组织，可以想象它们是通过激活编码功能不同蛋白质的宿主易感性 (S) 基因来促进疾病的。我们的目标是鉴定 RipTAL 激活的宿主 S 基因，这些基因在被给定的 RipTAL 转录上调时会促进细菌疾病。一旦宿主 S 基因被分离并进行功能验证，我们希望阐明 S 基因产物如何在分子水平上促进青枯菌疾病。从世界各地分离出的青枯菌菌株可分为四种系统发育型，这与其地理起源相关。值得注意的是，青枯菌系统发育型 I、II 和 IV 所含的 RipTAL 的 N 端和 C 端区域及其预测的 EBE 有所不同。到目前为止，RipTAL 的分子研究几乎全部针对来自系统发育型 I 的 RipTAL 进行。在本提案的框架中，我们的目标是还表征来自系统发育型 II 和 IV 菌株的 RipTAL，长期目标是识别和表征相应的宿主 S 基因和基因产物。总之，我们的目标是识别和表征由来自不同青枯菌系统型的 RipTAL 激活的宿主 S 基因。我们预计我们的研究结果将为青枯菌的疾病策略提供见解，有助于制定有效的对策来保护农作物。