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

本项目旨在研究大麦的系统重编程，它调节大麦与生物营养叶部病原菌Blumeria graminis f.sp.的亲和性相互作用。互生内生植物--印度梨形孢霉对根侵染的影响。我们最近的研究表明，担子菌在根中成功建立后，对大麦的耐盐性、对根部病害的抗性和更高的产量进行了重新编程(Waller等人，2005年)。在大麦叶片上成功地感染白粉病也会受到互惠真菌的干扰。这些过程与植物新陈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)进行深入的分析，并有两个特定的焦点：第一，阐明大麦根内互惠真菌的建立过程；第二，表征叶片中导致亲和性过程中断或失败的元件，这些过程是成功建立生物营养型叶片病原菌所需的。新的候选基因将通过在接种白粉菌后瞬时转化的大麦叶片来系统地预选它们在亲和性中的调节作用。经过验证的候选基因和其他项目(A1、A2、B5、B6)确定的基因产生了稳定的转基因大麦和玉米品系(B3)，这些品系将与白粉菌和稻瘟菌进行测试。通过比较不同植物-微生物系统中的候选基因，我们将确定与亲和性有关的共同调控过程、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.