马缨杜鹃杂交胚胎发育/败育的差异发育机理研究

Yunnan is one of the distribution center and differentiation center of Rhododendron subgenus Hymenanthes,which is rich in Hymenanthes germplasm resources but poor in its utilization. Distant hybridization barriers are the important reasons for limited use of resources.The crosses of Rhododendron delavayi as female, the extremely endangered species of R. cyanocarpum and the near threatened species of R.sinofalconeri as male parent respectively have been carried out before. The results showed that the pre fertilization barriers appeared in both crosses. However, the hybrid embryos had different developments as embryo development of the former cross and embryo abortion of the latter. In order to find out the reason, the pollination experiments of R. delavayi × R. cyanocarpum and R. delavayi × R. sinofalconeri would be carried out. The changes of cell morphology in the embryos different development of both crosses would be observed to determine the critical period of different embryo developments. The changes of the content of endogenous hormones between the unpollinated ovaries and the ovaries in the critical period of the different embryo developments of both crosses would be compared. Meanwhile, the differentially expressed proteins at the same two periods would be analyzed by iTRAQ-coupled 2D LC-MSMS. Systematic and comprehensive study of the hybrid embryo different development of R. delavayi would be done and the physiological and biochemical mechanism and the molecular mechanism of it would be revealed. As a result, the important scientific basis would be provided to the distant hybridization barriers of rhododendron.

云南是常绿杜鹃亚属的分布中心及分化中心之一，常绿杜鹃种质资源众多但利用率低下。远缘杂交障碍是限制其资源利用的重要原因。针对前期以马缨杜鹃为母本，易危杜鹃物种蓝果杜鹃和受危杜鹃物种宽杯杜鹃分别为父本进行远缘杂交时，前期均发生受精前障碍但后期杂交胚胎却出现发育（前者）和败育（后者）的差异发育现象，拟开展马缨杜鹃与蓝果杜鹃、马缨杜鹃与宽杯杜鹃的杂交授粉试验，观察杂交胚胎差异发育过程中的细胞形态变化，确定杂交胚胎差异发育的关键时期，对未授粉子房和杂交胚胎差异发育关键期子房的内源激素含量变化进行比较，并利用iTRAQ标记结合二维液相色谱串联质谱技术对同一时期的差异表达蛋白进行对比分析，系统和全面地研究马缨杜鹃杂交胚胎差异发育的细胞形态、生理生化机制及分子机理，为杜鹃花远缘杂交障碍研究提供重要的科学依据。

云南常绿杜鹃种质资源众多，但远缘杂交障碍却严重限制了资源的利用。开展马缨杜鹃杂交胚胎发育/败育的差异发育机理研究，可为杜鹃花远缘杂交障碍研究提供重要的科学依据。项目对马缨杜鹃与蓝果杜鹃（发育），马缨杜鹃与宽杯杜鹃（败育）杂交胚胎差异发育关键期的细胞形态变化，内源激素含量变化及差异蛋白表达进行研究。研究表明：1. 在鱼雷胚时期，杂交胚胎停止发育，胚囊解体，可能是导致马缨杜鹃×宽杯杜鹃杂交胚胎败育的主要原因；2. 在杂交子房的发育过程中，IAA、ZA和GA3的含量减少、ABA和JA的含量增加可能导致马缨杜鹃与宽杯杜鹃杂交胚胎发生败育；（IAA+ZA+GA3）/ABA可能对胚胎发育起调控作用，较低的（IAA+ZA+GA3）/ABA可能与杂交胚胎的败育有关；3.通过DIA-SWATCH蛋白组学分析，鉴定到马缨杜鹃×蓝果杜鹃，马缨杜鹃×宽杯杜鹃杂交子房间的差异表达蛋白97个，其中上调和下调表达蛋白分别为38个和59个。GO富集分析显示，差异蛋白主要执行代谢进程、单组织进程和细胞进程功能；KEGG富集分析中有光合作用-天线蛋白（ko00196）和氮代谢（ko00910）2条显著性富集路径，初步筛选出可能参与调控马缨杜鹃杂交子房败育的候选蛋白4个。马缨杜鹃×宽杯杜鹃杂交胚胎败育的形成可能与光合作用和碳水化合物运输与代谢等相关。本项目发表论文10篇，其中SCI收录2篇；申请相关专利3项，其中授权专利1项；培养在职博士研究生1名，研究生4名，外籍科技人员3名。通过项目的实施，加深了对杜鹃花远缘杂交胚胎发育障碍机理的认识，建立起杜鹃花远缘杂交育种技术体系，为杜鹃花远缘杂交育种提供了新的科学依据和技术支撑。