Barley compatibility factors pivotal for root colonisation and manipulation of basal defence by Piriformospora indica

本项目旨在研究大麦与生物营养性叶片病原菌Blumeria graminis f.sp的亲和性互作调控的系统重编程特性。内生真菌Piriformospora indica的根侵染。我们最近的研究表明，担子菌P. indica在根部成功建立后，会对大麦进行重定向，使其耐盐胁迫，抵抗根部病害，提高产量（Waller等，2005）。大麦叶片中成功的白粉病感染也受到共生真菌的干扰。这些过程与植物代谢的强烈变化有关，特别是与叶和根抗氧化剂的剧烈变化有关。在这些发现的基础上，我们将对大麦代谢组（B6）和转录组（B7）进行深入分析，并有两个具体的重点：首先，阐明大麦根内共生真菌的建立过程；其次，表征叶片中导致相容性过程中断或失败的系统反应元素，而相容性过程是成功建立生物营养性叶片病原体（如蓝藻）所必需的。新的候选基因将被系统地预先选择，通过瞬时转化的大麦叶片接种蓝毛菌在相容性中的调节作用。用已验证的候选基因和其他项目（A1, A2, B5, B6）鉴定的基因生成的稳定的转基因大麦和玉米品系（B3）将用蓝芽孢杆菌和籼稻进行试验。通过比较不同植物-微生物系统中的候选基因，我们将确定与兼容性相关的共同调节过程、代谢物和代谢网络，包括与互惠真菌成功相互作用所需的那些。

This project is aimed at the characterization of the systemic reprogramming in barley, which modulates the compatible interaction with the biotrophic leaf pathogen Blumeria graminis f.sp. hordei upon root infestation with the mutualistic endophyte Piriformospora indica. We have recently shown that the basidiomycete P. indica - upon successful establishment in the roots - reprograms barley to salt stress tolerance, resistance to root diseases and higher yield (Waller et al., 2005). Successful powdery mildew infections in barley leaves are also disturbed by the mutualistic fungus. These processes are associated with a strong change in plant metabolism, especially with a drastic alteration of leaf and root antioxidants. On the basis of these findings we will perform an in-depth analysis of the barley metabolome (B6) and transcriptome (B7) with two specific foci: First, to elucidate the process of establishment of the mutualistic fungus within the barley roots; second, to characterize elements of the systemic response in leaves leading to an interruption or failure of compatibility processes required for successful establishment of biotrophic leaf pathogens like Blumeria. New gene candidates will be pre-selected systematically for their regulatory role in compatibility by means of transiently transformed barley leaves upon Blumeria inoculation. Stable transgenic barley and maize lines (B3) generated with verified gene candidates and genes identified by other projects (A1, A2, B5, B6) will be tested with Blumeria and P. indica. By comparing candidate genes in the different plant - microbe systems, we will identify common regulatory processes, metabolites and metabolic networks implicated in compatibility including those required for successful interactions with mutualistic fungi.