Conservation of immunosuppression by Xanthomonadales commensals in Arabidopsis roots

拟南芥根中黄单胞菌共生体免疫抑制的保护

• 批准号: 466403757
• 负责人: Professor Dr. Paul Schulze-Lefert
• 金额: --
• 依托单位: Abteilung Pflanze-Mikroben Interaktionen
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/466403757?language=en
• 关键词: Conservation; immunosuppression; Xanthomonadales; commensals; Arabidopsis

Plant roots are colonized by a phylogenetically structured microbial community, called the root microbiota. We show that bacterial members of this community belonging to different taxa of the root microbiota differ in their ability to suppress immunity-associated responses in roots. The order Xanthomonadales defines a core lineage of the root microbiota of flowering plants, including Arabidopsis thaliana. Our preliminary results indicate that the ability of Xanthomonadales root commensals for immunosuppression is likely mediated by a conserved molecular mechanism. It remains unclear whether the commensals act only in specific root niches through a spatially and temporally controlled manipulation of defence responses. We selected the commensal Rhodanobacter R179, native to A. thaliana roots and representing the deepest branch of the order Xanthomonadales, and performed a mutant screen in planta using a library of R179 transposon insertion mutants. Ten defense suppression system (dss) R179 insertion mutants were identified that display impaired immunosuppressive activities compared with the wild-type commensal. We will investigate the presumed role of immunosuppression for spatio-temporal control of root colonization in mono-associations and community contexts. The dss mutants will also serve as basis to define the molecular mechanism(s) underlying Rhodanobacter R179 immunosuppression. We will examine the conservation of dss-dependent immunosuppression in phylogenetically diverse plantassociated Xanthomonadales commensals in roots. Finally, we will clarify the contribution of dss- and T3SS-dependent immunosuppression mechanisms and their potential mutual dependence for Xanthomonas pathogen colonisation in leaves.

植物根部由一种系统发育的微生物群落定植，称为根部微生物区系。我们表明，这个群落的细菌成员属于不同的根微生物区系，他们抑制根中免疫相关反应的能力不同。Xanthomonadales目定义了开花植物根微生物区系的核心谱系，包括拟南芥。我们的初步结果表明，黄单胞菌的根共生体对免疫抑制的能力可能是由保守的分子机制介导的。目前尚不清楚共生体是否通过在空间和时间上受控地操纵防御反应而仅在特定的根生态位中发挥作用。我们选择了共生红假单胞菌R179，它原产于拟南芥的根，代表黄单胞菌目的最深分支，并使用R179转座子插入突变体文库在Planta中进行了突变筛选。10个防御抑制系统(DSS)R179插入突变体被鉴定，与野生型共生相比，它们的免疫抑制活性受损。我们将研究免疫抑制在单一群丛和群落环境中对根定植的时空控制所起的假定作用。Dss突变体也将作为确定Rhodanbacter R179免疫抑制的分子机制(S)的基础。我们将研究DSS依赖的免疫抑制在系统发育不同的植物共生植物根中的保守性。最后，我们将阐明依赖DSS和T3SS的免疫抑制机制的贡献以及它们对Xanthomonas病原菌在叶片中定殖的潜在相互依赖。