小麦NF-YB转录因子家族成员介导植株抵御干旱逆境的分子机理

Through transcriptionally regulation of downstream stress-responsive genes, NF-Y type transcription factors play critical roles in mediating plant drought stress tolerance. In this project, based on our previous research results and using ten NF-YB transcription factor encoding genes of wheat (TaNF-YB1-TaNF-YB10) as basis, we will investigate the expression paterns of these tested genes in responding drought stress by using qRT-PCR, detect the distribution pattern of the fusion of each NF-YB with reporter protein green fluorescent protein (GFP) by which to understand the subcellular localizations of the NF-YB subunits, and identify distinct wheat NF-YC and NF-YA subunits that interact with the tested TaNF-YB transcription factors by performing yeast two hybridization (Y-2H) and bimolecular fluorescence complementation (BiFC) analyses, by which to elucidate the interaction models among these TaNF-YBs, TaNF-YCs and TaNF-YAs. In addition, we will identify the function of the tested wheat NF-YB encoding genes in mediating plant drought stress tolerance based on gene overexpression and RNAi methods, dissect the transcriptome, proteomics, gene network and corresponding biochemical pathway modulated by important wheat NF-YB genes by RNA-seq and iTRAQ approaches. Our current project can elucidate the functions and the related molecular mechanisms of the wheat NF-YB family members in mediating the plant drought stress tolerance.

NF-Y型转录因子通过在转录水平上对下游逆境响应基因进行调控，在介导植株抵御干旱胁迫逆境中发挥着重要作用。本课题在前期工作基础上，以在小麦中鉴定的10个NF-YB转录因子家族基因（TaNF-YB1~TaNF-YB10）为基础，采用实时定量PCR技术系统研究供试基因应答干旱逆境的时空表达模式；通过检测供试基因与绿色荧光蛋白基因（GFP）融合蛋白分布部位，明确供试基因编码蛋白亚细胞定位特征；利用酵母双杂交辅以BiFC技术，鉴定供试基因编码NF-YB蛋白可能互作的NF-YC和NF-YA组分，阐明小麦NF-Y转录因子亚基构成模式；通过基因过表达和表达干涉技术，鉴定供试基因介导植株抵御干旱逆境的能力；采用高通量RNA-Seq和iTRAQ技术，解析重要TaNF-YB基因特异调控的转录谱、蛋白谱、基因网络和生化代谢途径。通过研究系统阐明小麦NF-YB型转录因子基因介导植株抵御干旱逆境的功能和分子机制。

1..明确了NF-YB基因应答干旱表达模式、编码蛋白亚细胞定位特征.小麦NF-YB转录因子基因TaNF-YB3、TaNF-YB5、TaNF-YB6、TaNF-YB8和TaNF-YB11对干旱逆境产生应答。上述基因在干旱胁迫下表达发生改变，参与植株对干旱逆境的适应和抵御过程。上述小麦NF-YB基因编码蛋白定位于细胞核内。.2. 阐明了NF-YB转录因子家族基因编码蛋白互作组分和转录组特征及生化途径.鉴定了TaNF-YB11、TaNF-YB5和TaNF-YB6与NF-YA和NF-YC互作组分，包括TaNF-YA7、TaNF-YA1和TaNF-YC1。转录组分析表明， NF-YB基因对干旱处理植株中众多基因进行调控调控，在功能上归属与“生物学过程”、“细胞组分”和“分子功能”三个主要类别。 .3. 解析了NF-YB转录因子家族基因介导植株抵御干旱逆境能力及机制.建立了TaNF-YB11、TaNF-YB5和TaNF-YB6转化株系，鉴定了上述基因介导植株抵御干旱胁迫逆境的生物学功能。上述基因通过调控气孔关闭速率、细胞渗透调节物质合成、细胞保护酶活性以及相关酶编码基因转录，增强干旱逆境下植株光合能力、器官建成和干物质生产。 .4. 探明了NF-YB转录因子家族基因互作组分抵御干旱逆境功能及作用机制.对与NF-YB基因互作组分TaNF-YA7、TaNF-YA1和NF-YC家族成员抵御干旱胁迫功能进行了鉴定。上述NF-YB蛋白互作组分基因在表达特征上呈干旱诱导模式，上调表达调控干旱响应相关生理过程，包括根系建成和渗透调节物质合成及信号转导分子过程，增强植株抵御干旱胁迫功能。.5. 阐明了NF-YB转录因子家族基因调控因子抵御干旱逆境功能.对调控NF-YB基因包括ABA受体基因TaPYL4、TaPYR1及调控因子小分子RNA成员TaMIR5086和tae-miR8674a分子特征及介导植株抵御干旱胁迫的功能进行了研究。上述调控因子通过调控干旱处理下干旱逆境响应和抵御基因转录效率，影响植株干旱适应相关生化代谢，对植株适应干旱逆境的能力进行调控。.课题关键数据：获得了小麦种属NF-YB家族成员应答干旱胁迫表达、分子特征和介导植株抵御干旱相关形态、生理生化和分子过程相关关键数据。 .课题科学意义：揭示了重要应答干旱胁迫的小麦NF-YB转录因子家族基因介导植株抵御干旱逆境功能及分子机理。