花生中参与盐胁迫调控的MYB转录因子功能研究与花生耐盐种质创新

Soil salinization is a global problem affecting agricultural production and ecological environment。At present, there are mainly cotton, wheat, corn are planted in the saline-alkali soil. However, the plantation of these crops, especially cotton, has problems of low yield, large investment and low benefits, which lead to low enthusiasm of the farmers. Peanut has relative higher salt tolerance and has the potential to be a good alternative crop to optimize the agricultural structure in saline alkali soil area. It is an effective way to cultivate the new peanut varieties with salt tolerance, which can enlarge the area of peanut cultivation and increase the yield of peanut. It is important and effective means to produce abiotic stress tolerant varieties using transgenic techniques. However, little is known about the molecular mechanisms of salt stress regulation in peanut. The MYB transcription factors, especially R2R3-MYB, have important function in plant salt stress regulation. However, Little has been done about the MYB-related transcription factors in salt stress regulation of peanut and other plants. This project will screen the MYB transcription factors involved in the regulation of plant salt stress, and study their functions and mechanisms during salt stress regulation. At the same time, new salt tolerant peanut germplasms will be created by means of transgenic technology. This study will provide new gene resources for peanut abiotic stress regulation and new germplasm varities for molecular breeding.

土壤盐渍化是影响农业生产和生态环境的全球性问题。目前盐碱地种植作物主要有棉花、小麦、玉米，尤其是棉花产量低，投入大，效益低，农民积极性不高。花生耐盐能力较强，具有成为盐碱土区农业结构优化调整的优良替代作物的潜力。培育耐盐花生新品种，是扩大花生种植面积，提高花生产量的有效手段。通过分子生物学手段培育耐逆品种是重要及有效的手段，然而花生中有关盐胁迫抗性的分子生物学研究较少。MYB转录因子尤其是R2R3-MYB在植物盐胁迫调控中具有重要功能，而MYB-related类转录因子在植物盐胁迫中的研究较少，花生中尚未见报导。本项目在前期研究的基础上，筛选参与植物盐胁迫调控的MYB转录因子，研究其功能及作用机理。同时通过转基因手段创制耐盐花生新种质。本研究将为花生盐胁迫调控研究提供新的基因资源，为花生抗逆分子育种提供种质资源，具有重要的理论意义和实践意义。

培育耐盐花生新品种，是有效利用我国盐碱地，扩大花生种植面积，提高花生产量的有效手段。研究花生耐盐分子机理，有助于通过分子生物学手段培育耐逆品种。本项目在前期研究的基础上，筛选并克隆到8个花生中对盐胁迫响应的MYB基因，对这8个基因在非生物胁迫下的表达模式进行了详细研究。蛋白特性研究表明，AhMYB1，AhMYB6，AhMYB28和AhMYB30在酵母中具有转录自激活活性，AhMYB6，AhMYB28和AhMYB30定位于细胞核中，均符合转录因子特征。将AhMYB6和AhMYB30两个基因构建超表达载体分别转化拟南芥和花生。基因功能研究表明，AhMYB6在转基因拟南芥或花生中均提高了转基因植株对盐胁迫的抗性，AhMYB30在拟南芥中超表达对转基因植株耐盐性没有明显影响。随后对AhMYB6在拟南芥中的作用机理进行了详细分析，结果表明AhMYB6提高转基因植株盐胁迫抗性的机理主要是增强了转基因植株对ABA的敏感性，促进水分胁迫下叶片气孔的关闭，增加了盐胁迫下可溶性糖和脯氨酸的积累。非生物胁迫中下游marker基因表达分析表明，AhMYB6促进转基因植株盐胁迫抗性可能通过ABA-dependent和ABA-independent两条路径进行。此外，本研究还通过化学诱变和辐射诱变及盐碱地种植鉴定，筛选到3份耐盐突变体种质资源。本研究为花生盐胁迫调控研究提供新的基因资源，为花生抗逆分子育种提供种质资源，具有重要的理论意义和实践意义。

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