荒漠孑遗植物沙冬青遗传资源及抗逆基因的功能评价

Ammopiptanthus mongolicus, a relic plant, is the only broadleaf evergreen species living in the desert area located in northwestern China. It is has enormous developmental potential as the species is highly capable of resisting drought, cold and salty conditions. Hence the corresponding genes of A.mongolicus have attracted great attentions of the academia. Currently, there are few researches addressing the molecular mechanism of the drought response in A. mongolicus due to the lack of nucleotide sequence data. Based on the existing researches, this project intends to (a) establish a high quality transcriptome database with the high-throughput sequencing technology ; (b) study the molecular regulation features of roots,stems and leaves of A.mongolicus when it is responding to drought conditions using custom-built gene chips and determine the performing genes in the process of stress tolerance; (c) select 3 WRKY transcription factors and conduct gene cloning, stress expression profiling, protein subcellular location analysis and transgenetic ectopic expression analysis with the aim to elucidating to the functions of these genes in stress adaptation in A.mongolicus and evaluate their possible applications in improving the plant drought tolerance. This project will protect genetic resources, advance the understanding on plant stress adaptation in molecular level and provide good candidate genes for genetic engineering for plant abiotic stress resistance.

荒漠孑遗植物沙冬青是我国西北部荒漠地区唯一的超旱生常绿阔叶树种，具有耐旱、耐寒、耐盐碱等多种抗性，其基因组中蕴藏着大量优异的抗逆基因，是具有巨大开发潜质的重要的遗传资源。目前，由于缺乏足够的基因序列数据，对沙冬青耐旱分子响应特征和耐旱相关基因的研究较少。本项目拟基于已有的研究工作基础，采用高通量测序技术建立高质量的蒙古沙冬青转录本数据库；应用定制基因芯片等技术研究蒙古沙冬青根、茎和叶应答干旱逆境的分子调控特征，确定在干旱耐受中发挥作用的关键基因；在此基础上，选择3个WRKY转录因子基因进行克隆，通过逆境表达模式分析、亚细胞定位和转基因研究，阐明蒙古沙冬青WRKY类转录因子中具有应答干旱逆境的种类和作用特点，进行基因功能评价。本研究将有助于保护和利用遗传资源，加深对荒漠植物抗逆分子机制的认识，筛选、鉴定抗逆优秀基因，为培育抗逆植物品种提供基因资源。

荒漠孑遗植物沙冬青是我国西北部荒漠地区唯一的超旱生常绿阔叶树种，具有耐旱、耐寒等多种抗性。沙冬青基因组中可能蕴藏着大量抗逆基因，是具有巨大开发潜质的重要遗传资源。本项目采用高通量测序技术建立了高质量的蒙古沙冬青叶片的转录本数据库，确定了在叶片干旱耐受中发挥作用的关键基因。将前期建立的蒙古沙冬青根转录本数据和本项目建立的叶片转录本数据以及NCBI上现有的蒙古沙冬青转录组数据合并，构建了高覆盖度的蒙古沙冬青转录本数据库。通过对转录本数据库中应答逆境的WRKY转录因子基因的筛选，获得了49个编码WRKY转录因子全长基因序列，进行了结构和系统进化分析。克隆了4个编码WRKY、2个编码DREB和4个编码MYB转录因子基因，通过逆境表达模式分析、亚细胞定位和转基因等进行了基因功能评价研究。对蒙古沙冬青和新疆沙冬青进行比较转录组分析，确定2个近缘物种分化的时间可能在0.70 ± 0.62 Mya前。开展了蒙古沙冬青miRNA的系统鉴定及逆境应答miRNA的鉴定工作，获得了保守和非保守的miRNA。采用双向电泳和iTRAQ技术分析了蒙古沙冬青不同组织应答逆境的蛋白质组的表达特点。相关研究成果已撰文发表。本项目通过开展上述研究所获得的研究结果为揭示蒙古沙冬青逆境应答的分子机制提供了重要数据。