Transcriptome landscape of a bacterial pathogen under plant immunity
Transcriptome landscape of a bacterial pathogen under plant immunity
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DOI：
10.1073/pnas.1800529115
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发表时间：
2018-03-27
影响因子：
11.1
通讯作者：
Tsuda, Kenichi
中科院分区：
文献类型：
--
作者：
Nobori, Tatsuya;Velasquez, Andre C.;Tsuda, Kenichi
植物病原体可导致严重的疾病，影响全球农业。植物的先天免疫，当完全激活时，可以阻止病原体在植物中的生长。尽管对植物对病原体免疫的分子和遗传基础进行了广泛的研究，但对植物免疫在全球病原体代谢中限制病原体生长的影响知之甚少。在这里，我们开发了用于分析植物中细菌转录组的RNA测序管道，并确定了拟南芥中叶面细菌病原体假单胞菌的高分辨率转录组模式，共27种植物免疫突变体和细菌菌株的组合。在感染后6 h分析细菌转录组，以捕获植物免疫对细菌过程的早期影响，并避免由植物中不同细菌种群密度引起的二次影响。我们确定了特定的“免疫应答”细菌基因和过程，包括那些在易感植物中被激活并被植物免疫激活抑制的基因和过程。在不同宿主基因型中，早期时间点的免疫应答细菌基因的表达模式与后期细菌生长水平紧密相关。此外，我们发现细菌铁的获取途径通常被多种植物免疫信号通路抑制。在AvrRpt 2引发的植物免疫应答期间，参与铁调节和其他过程的P.lingae sigma因子基因的过表达部分地对抗了细菌生长限制。总的来说，这项研究定义了植物免疫对细菌病原体转录组的影响，并揭示了植物免疫反应过程中细菌生长抑制的神秘机制。
Plant pathogens can cause serious diseases that impact global agriculture. The plant innate immunity, when fully activated, can halt pathogen growth in plants. Despite extensive studies into the molecular and genetic bases of plant immunity against pathogens, the influence of plant immunity in global pathogen metabolism to restrict pathogen growth is poorly understood. Here, we developed RNA sequencing pipelines for analyzing bacterial transcriptomes in planta and determined high-resolution transcriptome patterns of the foliar bacterial pathogen Pseudomonas syringae in Arabidopsis thaliana with a total of 27 combinations of plant immunity mutants and bacterial strains. Bacterial transcriptomes were analyzed at 6 h post infection to capture early effects of plant immunity on bacterial processes and to avoid secondary effects caused by different bacterial population densities in planta. We identified specific "immune-responsive" bacterial genes and processes, including those that are activated in susceptible plants and suppressed by plant immune activation. Expression patterns of immune-responsive bacterial genes at the early time point were tightly linked to later bacterial growth levels in different host genotypes. Moreover, we found that a bacterial iron acquisition pathway is commonly suppressed by multiple plant immune-signaling pathways. Overexpression of a P. syringae sigma factor gene involved in iron regulation and other processes partially countered bacterial growth restriction during the plant immune response triggered by AvrRpt2. Collectively, this study defines the effects of plant immunity on the transcriptome of a bacterial pathogen and sheds light on the enigmatic mechanisms of bacterial growth inhibition during the plant immune response.