长白落叶松MYB基因在木质素生物合成过程中调控功能的研究

In order to solve the problem of timber is in short supply, selecting and breeding fast-growing and high quality species is the priority, but long cycle of conventional breeding limits its research and development progress. In our study, MYB transcription factors of Larix olgensis is the research object, we want to know how the LoMYB affects on lignin synthesis by time-space expression characteristic analysis and growth, wood property comparison analysis between gene over expression transgenic lines, antisense suppressed transgenic lines and wild type, while make sure which lignin synthesis pathway the gene participates by screening its regulating target genes. The research could lay the foundation of culture excellent pulpwood larch by molecular biology methods, we also want to make the molecular mechanism breakthrough of revealing wood characteristics forming, reach or approach advanced international standards of forestry tree research hotpot such as cambium activity, xylem cell differentiation and development, gene expression regulation and so on, while make a contribution to improve the plantation species by genetic engineering in the future.

为解决木材供应紧张，应选育速生、优质的林木品种，但是常规育种耗时周期长限制了其研究发展的进度。本研究以长白落叶松转录因子MYB基因为研究对象，通过LoMYB基因的时空表达特性分析，获得LoMYB过表达及抑制表达转基因植株与野生型植株在生长性状和材性性状的对比分析找出LoMYB基因对木质素合成的影响，通过其调控的靶基因的筛选确定LoMYB基因参与的木质素代谢合成途径，进而综合分析得出LoMYB基因在木质素生物合成过程中的调控机理，为利用分子生物学手段培育低木质素的优良长白落叶松纸浆材新品种奠定基础。本项目的研究，可以在揭示长白落叶松木材材性形成的分子机理研究上有所突破，在树木形成层的活动、木质部细胞的分化与发育，相关基因的表达与调控等林木研究热点领域达到国际先进水平，同时为后期应用基因工程手段定向改良我国人工林建设急需树种做出贡献。

MYB转录因子是植物最大的转录因子基因家族之一，本研究前期通过长白落叶松形成层差异表达基因挖掘得到八条全长MYB基因，通过基因表达量分析发现c71764基因在茎中表达量较高，命名为LoMYB8。生物信息学分析表明该基因是定位在细胞核中的具有转录激活活性的转录因子，其在茎中表达量高于根和叶。构建过表达及CRISPR载体对落叶松进行遗传转化，获得了基因瞬时表达及稳定表达植株和细胞系。进一步分析表明该基因可能参与糖类、氨基酸、黄酮类等物质的合成和代谢相关相途径，可以引起次生代谢物质等含量发生变化。本项目的研究结果对完善木本植物特别是针叶树种MYB基因的功能具有重要意义，为落叶松其它基因的研究也提供了借鉴。