Regulation of the metabolic adaptation of the phytopathogenic bacteria Xanthomonas campestris pv. campestris and Xanthomonas campestris pv. armoraciae during infection of Arabidopsis thaliana

本研究的重点是野油菜黄单胞菌的代谢调控网络。Campestris(Xcc)和野油菜黄单胞菌(Xanthomonas campestris PV.)作为十字花科植物病原菌的Armorciae(Xca)。这两个致病变种的完整基因组序列都是可用的，模式植物拟南芥将被用作宿主。这一建议的具体焦点是在代谢途径和基因调控网络水平上的细菌在感染期间的代谢适应动态。我们假设细菌的活动改变了植物的新陈代谢，进而影响细菌的活动。或者换句话说，细菌与植物的相互作用可以被看作是一个(新陈代谢)相互作用的级联网络。假设细菌在致病相互作用过程中处于不同的代谢阶段。我们的目标是建立一个新陈代谢模型，以模拟这些阶段。该模型应该根据不同的营养来源预测代谢流量的变化，以及对编码中心酶的基因突变的适应。将采用一种标记签名的突变方法来鉴定与寄主植物感染和定居有关的基因。计划进行13C标记实验和特异性诱变，以建立与适应植物生活方式相关的条件下的代谢通量。最后，在利用荧光报告基因构建的植物定殖过程监测中，将使用Xanthomonas在感染的不同阶段建立代谢适应的动态视图。

This proposal focuses on the metabolic regulatory networks of Xanthomonas campestris pv. campestris (Xcc) and Xanthomonas campestris pv. armoraciae (Xca) as pathogens of cruciferous plants. Complete genome sequences for both pathovars are available and the model plant Arabidopsis thaliana will be used as host. The specific focus of this proposal is the dynamics of bacterial metabolic adaptation during infection on the level of metabolic pathways and gene regulatory networks. We assume that the bacterial activity changes the plant metabolism, what in turn influences the bacterial activity. Or in other words, the bacterial plant interaction can be seen as a cascading network of (metabolic) interactions. The hypothesis is that bacteria exist in different metabolic stages during the pathogenic interaction. We aim to establish a metabolic model allowing for simulation of these stages. The model should predict changes in metabolic flux in accordance to different nutrient sources and the adaptation to mutations in genes coding for central enzymes. A signature-tagged mutagenesis approach for the identification of genes relevant to infection and colonization of the host plant will be carried out. 13C-labeling experiments and specific mutagenesis is planned to establish the metabolic flux under conditions relevant for the adaptation to the in planta life style. Finally, in planta monitoring of the colonization process using fluorescent reporter gene constructs will be used to establish a dynamic view of the metabolic adaptation of Xanthomonas during the different stages of infection.