玉米MAPK家族基因的分离鉴定及其在花粉发育和花粉管生长过程中的功能分析

Mitogen-activated protein kinases (MAPKs) play important roles in plant development via regulating their resistances to external stimulus and hormone signal transduction processes. However, their roles in plant reproduction, especially pollen development and pollen tube growth, are largely unknown. Maize (Zea mays L.) is one of the most important crops in China, identify all members of MAPK gene family and uncover their roles in pollen development and pollen tube growth have a vital significance. It not only could add new MAPK cascades, but also could provide basis to improve the yield and quality of maize. In this study, 20 MAPK genes were identified in maize by using bioinformatics and molecular biology tools. Among them, three genes, named ZmMPK13, ZmMPK16 and ZmMPK17, were found to be expressed specifically or preferentially in mature pollen grains. In addition, our previous transcriptome analysis showed that their expression levels were up-regulated remarkably after pollination. Combined the previous founding with our current research, we suggest that the three maize MAPKs might take part in regulating pollen development and pollen tube growth. We plan to establish new MAPK cascades that regulate pollen development and pollen tube growth in maize through the following strategies: 1) analyze the spatiotemporal expression patterns and subcellular locations of the three MAPKs in maize; 2) use transient and stable transformation systems to investigate the function of the three MAPKs in plant reproduction processes; 3) identify substrates of MAPKs that play roles in pollen development and tube growth.

MAPK蛋白激酶在植物抵御各类胁迫及植物激素的信号转导过程中具有重要作用，但其在植物有性生殖，特别是花粉发育与花粉管生长中的功能则知之甚少。玉米是我国最重要的粮食作物，分离和鉴定玉米中全部MAPK家族成员并挖掘其在花粉发育及花粉管生长过程中的作用，不仅可以丰富现有的MAPK级联通路，而且对于提高玉米的产量和品质具有极大的指导价值。本研究首先通过生物信息学和分子生物学手段获得了20个玉米的MAPK基因，对这些基因的表达分析发现，其中三个基因：ZmMPK13，ZmMPK16和ZmMPK17，都特异或主要在玉米花粉中表达，且授粉后它们的表达水平都显著上调。这就暗示了这三个基因很可能调控了玉米花粉的发育及花粉管生长过程。本研究将对这三个基因时空表达模式、亚细胞定位进行分析，进而通过稳定和瞬时转化系统研究它们在植物有性生殖中的作用，最后通过蛋白互作分析建立调控这个过程的MAPK级联信号通路。

MAPK蛋白激酶在植物抵御各类胁迫及植物激素的信号转导过程中具有重要作用，但其在植物有性生殖，特别是花粉发育与花粉管生长中的功能则知之甚少。玉米是我国最重要的粮食作物，分离和鉴定玉米中全部MAPK家族成员并挖掘其在花粉发育及花粉管生长过程中的作用，不仅可以丰富现有的MAPK级联通路，而且对于提高玉米的产量和品质具有极大的指导价值。本研究首先通过生物信息学和分子生物学手段获得了20个玉米的MAPK基因，对这些基因的表达模式分析发现，其中三个基因：ZmMPK13，ZmMPK16和ZmMPK17，都特异或主要在玉米花药和花粉中表达，且授粉后它们的表达水平都显著上调。这就暗示了这三个基因很可能调控了玉米花粉的发育及花粉管生长过程。亚细胞定位结果显示，ZmMPK17仅定位于细胞核中，ZmMPK13和ZmMPK16则定位于细胞核和细胞膜中。对三个基因的过量表达植株的功能分析结果显示，ZmMPK13和ZmMPK16的过量表达对花粉育性无显著影响，ZmMPK17过量表达后，转基因植株表现出花粉部分败育、种子变小的表型。本研究的进行为揭示玉米MAPK家族基因在植物育性调控方面的机制奠定了基础。