Rapid adaptation of signaling networks in the fungal Pathogen Magnaporthe oryzae

非常多样化的真核信号网络是如何进化的，这一问题具有巨大的科学意义。生物体的进化适应通常被认为是长期作用的过程的结果。最近的观察表明，微生物能够迅速适应新的环境，并通过自然选择建立稳定的表型，即使在几代内也是如此。我们发现，在盐胁迫下，丝状稻瘟菌能够在几个独立的高渗透压甘油(HOG)途径的“功能丧失”(LOF)突变体中快速重连渗透调节所需的信号转导。适应导致模式生物的稳定突变在渗透调节中得到恢复，作为从盐敏感突变体中生长出来的个体。这些快速适应的菌株在盐胁迫下产生的主要相容溶质被发现是甘油，而在野生型菌株中是阿拉伯醇。这些发现导致了一种假设，即持续的环境进化压力下的稳定适应事件使稻瘟病菌能够迅速恢复或修改整个信号网络。为了解决这一假说，我们的目标是识别这种快速进化适应的分子或生化机制，并表征使能或阻止适应的相关因素和信号通路。两个项目伙伴将协同互动，将理论方法的专门知识结合起来，将基因组学和转录组学的测序数据与现代定量(磷)蛋白质组学技术相结合。此外，反向分子遗传学将被用来验证候选基因或甚至其他被发现可能促进或限制快速进化适应的因素(如磷酸化模式)。因此，拟议的项目将为研究真核微生物表型和遗传进化的关系打开大门。

The question of how the remarkably diverse array of eukaryotic signaling networks has evolved is of enormous scientific relevance. Evolutionary adaptation of living organisms is commonly thought to be the result of processes that acted over long periods of time. The proposed project is motivated by recent observations that microorganisms are able to rapidly adapt to new environments and establish stable phenotypes by natural selection, even within few generations. We found the filamentous rice blast fungus Magnaporthe oryzae to rapidly rewire signal transduction required for osmoregulation in several independent “loss of function” (lof)-mutants of the High Osmolarity Glycerol (HOG)-pathway upon exposure to salt stress. Adaptation resulted in stable mutants of the model organism being restored in osmoregulation arising as individuals outgrowing from salt-sensitive lof-mutants. The major compatible solute produced upon salt stress by these rapidly “adapted” strains was found to be glycerol whereas it is arabitol in the wildtype strains. These findings lead to the hypothesis that stable adaptation-events under continuously environmental evolutionary pressure enable Magnaporthe oryzae to rapidly restore or modify entire signaling networks. To address this hypothesis, we aim to identify the molecular or biochemical mechanisms of this rapid evolutionary adaption and characterize associated factors and signalling pathways which enable or prevent adaption. Both project partners will interact synergistically to combine expertise of theoretical approaches to integrate sequencing data from genomics and transcriptomics with modern quantitative (phospho)-proteomics techniques. Furthermore, reversed molecular genetics will be used to validate the candidate genes or even other factors (e.g. phosphorylation patterns) found to be putatively promote or constrain rapid evolutionary adaptation. Consequently, the proposed project will open the door to investigate the relationship of phenotypic and genetic evolution in eukaryotic microorganisms.