钙信号转导途径参与盐胁迫激活真菌漆酶基因转录的分子机制研究

Previous research have suggested that calcium signaling pathway mediated by calmodulin may play a role in the regulation of laccase gene expression. In our previous research, we find that the salt stress can strongly stimulate and enhance the transcription of laccase gene lac48424-1 in the white-rot fungus Trametes sp.48424. The calcium signaling pathway mediated by calmodulin and calmodulin-dependent protein kinase plays an important role in the induction of laccase gene transcription by the salt stress. But what is the molecular mechanism of regulating the laccase gene transcription by the salt stress through the calcium signaling pathway? Which components and functional proteins exist in the downstream of calmodulin in this signal transduction pathway involved in the regulation of laccase gene transcription? These problems remain unsolved and are worth studying. In this project, based on our previous research, we plan to study the molecular mechanism of inducing the laccase gene transcription by the salt stress through calcium signaling pathway. Our study aims to indentify the critical components and their interaction in the calcium signaling pathway involved in the regulation of laccase gene transcription by the salt stress. Our work will provide new insights and information for unveiling the molecular mechanism of regulation of laccase gene expression in white-rot fungi. In addition, this research will provide the novel and effective target for molecular breeding of high laccase-producing and high lignin-degrading fungal strains. It will also lay a solid theoretical foundation for highly improving the natural laccase production by white-rot fungi.

已有研究表明钙调蛋白介导的钙信号转导途径在白腐真菌漆酶基因表达调控中发挥了作用。我们前期研究发现盐胁迫条件对白腐真菌Trametes sp.48424的lac48424-1漆酶基因的转录具有强烈的诱导激活效应，以钙调蛋白/钙调蛋白依赖性蛋白激酶为核心的钙信号途径在盐胁迫诱导激活漆酶基因转录的过程中发挥了重要作用。但是钙信号途径参与盐胁迫调控漆酶基因转录的分子作用机制是什么？调控漆酶基因转录的钙调蛋白下游信号传递途径的关键组成成分和功能蛋白有哪些？它们之间是如何作用的？这些问题尚未解决值得深入研究。本项目将在我们前期工作基础上，深入研究钙信号转导途径参与盐胁迫激活漆酶基因转录的具体分子机制，解析调控漆酶基因转录的钙信号转导途径的关键组成成分及其相互作用。研究意义在于为深入揭示真菌漆酶基因表达调控机制提供有价值的新信息新观点，为高产天然漆酶的真菌基因工程菌株的构建和分子育种提供新的有效作用靶点

已有研究表明钙调蛋白介导的钙信号转导途径在白腐真菌漆酶基因表达调控中发挥了作用，但是钙信号途径参与盐胁迫调控漆酶基因转录的分子作用机制尚不清楚。本研究主要研究了钙信号转导途径参与盐胁迫激活漆酶基因转录的具体分子机制，解析调控漆酶基因转录的钙信号转导途径的关键组成成分。盐胁迫条件对真菌漆酶基因的转录具有较强的诱导激活效应，盐胁迫条件能够诱导增强钙信号转导途径关键基因Tr-CaM和Tr-CaMK的表达量。进一步对CaM-CaMK信号途径参与盐胁迫激活漆酶基因转录的功能进行了研究，CaM-CaMK信号途径在盐胁迫激活漆酶基因转录的过程中发挥重要作用。在以上工作基础上进一步探究了CaM-CaMK信号途径参与盐胁迫激活漆酶基因转录的分子机制，鉴定了参与盐胁迫激活漆酶基因转录的顺式调控元件（盐胁迫响应元件）和反式作用因子（盐胁迫响应转录因子），进一步对盐胁迫响应转录因子与盐胁迫响应元件之间的相互作用进行了研究。对Tr-CaMK的生化功能进行了初步鉴定，对Tr-CaM和Tr-CaMK之间的相互作用进行了研究，初步验证Tr-CaMK是Tr-CaM作用的下游靶蛋白。另外我们还研究了除盐胁迫之外的其它胁迫条件对真菌漆酶基因家族6个不同漆酶同工酶基因的转录调控，重点开展了有机溶剂胁迫条件对真菌漆酶基因家族6个不同漆酶同工酶基因的转录调控研究。本研究为深入揭示钙信号途径调控真菌木质素降解酶基因表达的生物学功能和作用机制提供了有价值的新信息和新线索，对于深入全面揭示真菌漆酶基因表达调控机制也具有较好的促进作用。