CNGC mediated signal transduction and networking in plant immunity

为了支持对粮食生产日益增长的需求，在农业生产中保护植物免受各种病原体和昆虫侵害的农用化学品的使用在过去几十年中急剧增加。然而，这些化学品的负面环境影响正在成为全世界的一个严重问题。此外，尽管广泛使用这些农用化学品，但植物病害造成的全球作物损失每年约为2200亿美元。为了解决这些问题，必须培育抗病原体作物和环境友好型农用化学品。为此，在分子水平上了解植物自身的自然防御系统至关重要。在过去的十年中，人们对植物免疫的识别和信号转导进行了广泛的研究。然而，病原体识别后的信号转导级联反应在很大程度上仍然是未知的。为了鉴定抗性信号通路的组成部分，我们已经对表现出病原体抗性改变的拟南芥突变体进行了筛选。通过该筛选，我们鉴定了表现出各种防御反应的组成性激活的cpr 22。在过去的四年半中，我们已经确定了cpr 22基因作为一个不寻常的嵌合环核苷酸门控离子通道基因（AtCNGC 11/12），并报道了AtCNGC 11/12的瞬时表达诱导钙依赖性程序性细胞死亡。我们关于AtCNGC 11和12的数据以及其他研究小组关于AtCNGC 2和4的数据强烈表明CNGC在植物免疫中的重要作用。然而，它们参与诱导抗性反应和CNGC介导的信号转导级联的分子机制在很大程度上仍然未知。本研究旨在阐明CNGC介导的植物免疫信号转导的分子机制。该提案的结果肯定会提高我们对CNGC在植物免疫系统中作用的理解，并有助于发现病原体和农用化学品引起的农业/环境问题的实际解决方案。

To support the growing demand for food production, the usage of agrochemicals, which protect plants from various pathogens and insects in agricultural production, has increased dramatically over the last decades. However, the negative environmental effects of these chemicals are becoming a serious issue all over the world. Furthermore, despite of the extensive use of these agrochemicals, the worldwide crop loss caused by plant disease is approximately $220 billion annually. To address these issues, the generation of pathogen resistant crops and environmentally friendly agrochemicals are essential. For this aim, it is crucial to understand the plant's own natural defense system at the molecular level. During the past decade, extensive efforts have been made to understand the recognition and signal transduction in plant immunity. However, the signal transduction cascade following pathogen recognition is still largely unknown. In order to identify components of the resistance signaling pathway, we have conducted a screening for Arabidopsis mutants which show alterations in pathogen resistance. Through this screen we identified cpr22 that exhibits constitutive activation of various defense responses. In the past four and half years we have identified the cpr22 gene as an unusual chimeric cyclic nucleotide-gated ion channel gene (AtCNGC11/12) and reported that the transient expression of AtCNGC11/12 induces Ca2+-dependent programmed cell death. Our data about AtCNGC11 and 12, and the data from other research groups about AtCNGC2 and 4 strongly indicate significant roles of CNGCs in plant immunity. However the molecular mechanism of their involvement in the induction of resistance responses and the CNGC-mediated signal transduction cascade are still largely unknown. The aim of this proposal is to elucidate the molecular mechanism of CNGC mediated signal transduction in plant immunity. The outcome of this proposal certainly will improve our understanding of the role of CNGCs in the plant immune system and also contribute to discover practical solutions for agricultural/environmental issues caused by pathogens and agrochemicals.