Mechanisms of fungal pathogens' adaptation to plant defenses

了解病原体如何感染植物以及植物如何应对此类攻击对于开发基于知识的植物病害管理策略至关重要。然而，真菌病原体采取的措施，以抵消植物防御也是等式的重要组成部分。我的研究计划目前侧重于了解病原体如何应对植物防御策略，以及它们如何操纵植物的新陈代谢，使其对自己有利。我们通过评估它们对植物防御机制的影响，使用两个病理系统，马铃薯-大丽轮枝菌和马铃薯-致病疫霉，验证这些反防御的机制。利用蛋白质组学和消减杂交（SH）/cDNA-AFLP组合的方法，我们确定了几个差异表达的基因和蛋白质可能参与这两个病理系统。在大丽轮枝菌中，我们鉴定了仅在高侵袭性分离株中差异表达的基因和蛋白质，并且仅在用马铃薯根提取物诱导后差异表达。可能参与反防御的基因和蛋白质正在研究中。我的研究计划的目标是调查是否以及如何潜在的致病性基因和蛋白质，只表达在高侵略性的分离株的大丽轮枝菌（即，SrrA，ICH）影响植物防御并改变宿主-病原体相互作用的结果，以及病原体如何在基因和代谢物水平上协调这种植物防御改变。病原体对宿主的适应似乎在涉及环境的全球问题（如气候变化）中更为重要。能够预测病原体的适应性反应将为通过靶向病原体的特定功能来处理植物疾病开辟新的视野。

Understanding how pathogens infect plants and how plants respond to such attacks is critical for the development of knowledge-based plant disease management strategies. However, the measures taken by fungal pathogens to counteract plant defenses also are important parts of the equation. My research program currently focuses on understanding how pathogens respond to plant defense strategies and how they manipulate plants' metabolism to their advantage. We validate the mechanisms underlying these counterdefenses by assessing their impact on plant defense mechanisms using two pathosystems, potato-Verticillium dahliae and potato- Phytophthora infestans. Using proteomics and a subtractive hybridization (SH)/cDNA-AFLP combinational approach, we identified several differentially expressed genes and proteins potentially involved in these two pathosystems. In V. dahliae, we identified genes and proteins differentially expressed only in a highly, not a weakly, aggressive isolate and only after induction with potato root extracts. Genes and proteins potentially involved in counterdefense are being investigated. The objectives of my research program for the term of this Discovery grant proposal are to investigate whether and how potential pathogenicity genes and proteins that express only in highly aggressive isolates of V. dahliae (i.e., SrrA, ICH) impact plant defenses and alter the outcome of host-pathogen interactions, and how the pathogen coordinates such plant defense alterations at gene and metabolite levels. Adaptation of pathogens to their hosts will seemingly be more significant under global issues involving the environment, such as climate change. Being able to anticipate adaptive reactions of pathogens will open new horizons in dealing with plant diseases by targeting specific functions of the pathogen.