鹅掌楸柱头与花粉识别过程的转录组分析及关键基因挖掘

Pollen-pistil interaction is a key event in reproductive process of plants. Launching a pollen-stigma recognition mechanism research of Liriodendron which is a rare and endangered plant and has higher commercial value and important scientific value, has an important significance for revealing its endangered mechanism and promoting protection and breeding. Preliminary studies in our laboratory showed that the setting percentages of Liriodendron are significant different between selfing and outcrossing; it also showed that the male and female gametes can develop normally, but the pollen tube growth in stigma is partially abnormal. Based on the preliminary studies, we plan to extract the total RNAs and proteins from the stigma which are un-pollinated, 1h after pollinating, 6h after pollinating, and then do transcriptome sequencing and proteins identification by Solexa and MALDI-TOF/TOF-MS respectively. After bioinformatic analysis, we can not only get the genes expression profiling of pollen and stigma, but also find out the genes which involve in pollen-stigma recognition and build the genes regulatory network in recognition. This project will contribute to explain the mechanism of liriodendron pollen-stigma recognition and lay a foundation for Liriodendron breeding and cross breeding.

柱头对花粉的识别是植物完成有性生殖过程的关键步骤。对具有极高经济价值和重要科研价值的珍稀濒危植物鹅掌楸开展柱头与花粉识别机理的研究，对于揭示鹅掌楸濒危机制，促进鹅掌楸的保护与繁育具有重要意义。本实验室的前期研究中，发现鹅掌楸的自交与异交结实率存在显著差异；通过细胞生物学手段发现花粉和胚囊发育正常，但花粉管在柱头上生长存在异常现象。在前期研究工作的基础之上，本项目拟通过转录组学和蛋白质组学相结合的策略，从未授粉柱头、授粉1h、授粉6h柱头基因的表达差异入手，提取相应处理组的样品总RNA，进行RNA测序和深度的生物信息学分析。这不仅能够建立鹅掌楸授粉过程中柱头、花粉基因表达谱；而且能够系统研究授粉不同阶段鹅掌楸柱头的转录组变化，挖掘参与授粉过程中柱头与花粉识别的有关基因，构建相关基因的调控网络，揭示鹅掌楸柱头与花粉识别的分子机理，为鹅掌楸繁育以及杂交育种奠定基础。

本研究关注具有极高经济价值和重要科研价值的珍稀濒危植物中国鹅掌楸的低结实率现象， 通过利用蛋白质组学和转录组学开展柱头与花粉识别机理的研究，通过该项目的实施，鉴定出65个差异表达的分别参与胚发育、花粉管发育、双受精过程中合子形成等等与生殖过程密切相关的途径的蛋白质。转录组学数据分析得到1252个鹅掌楸柱头特异表达基因和171个参与生殖过程差异表达基因，其中49个基因的表达水平在授粉前后变化倍率在2倍及以上，基因功能分析显示这些基因参与柱头与花粉的识别过程具体包括（1）参与柱头与花粉识别，（2）参与花粉在柱头萌发，（3）花粉管生长引导等。相关研究结果已整理成文发表一篇，目前仍有一篇处于投稿过程中。该研究结果对于进一步探究和揭示鹅掌楸低结实率的原因具有重要的指导意义。