PBU诱导尾巨桉体胚发生的受体基因分离及与miR166应答机制研究

桉树是世界三大经济林树种之一，中国桉树种植面积已有368万hm2，占国内纸浆用材的50%以上。作为遗传转化的良好受体，胚性愈伤组织及胚状体的诱导一直深受研究者重视。近年来，应用本实验室自主合成且在南方花卉苗木组织培养中广泛应用的新型植物生长调节剂PBU（专利号：ZL200510035860.X）调控尾巨桉愈伤组织分化，获得了高频发生的胚性愈伤组织和体细胞胚。前期研究中发现，miR166 家族在桉树体胚发生过程中，表达水平上调显著，且与PBU的诱导作用表现出较紧密的相关关系。本研究通过分离PBU受体及其目标基因，探讨miR166基因上游激素响应元件与PBU的应答机制，确定PBU及miR166基因在尾巨桉体胚发生过程中的生物学功能，为解析桉树体胚发生的分子机理提供依据，进一步促进PBU在桉树离体快繁及体胚发生中的应用。

Eucalyptus is the main no-timber trees in tropical and subtropical regions. Eucalyptus is the most important forest tree in China, covering more than 3.68 million hectares of commercial plantations. More than 50% pulp is provided by Eucalyptus. Embryonic callus and somatic embryogenesis induction has always been given great concern as a superior acceptor system of gene transfer. Embryonic callus and somatic embryogenesis in Eucalyptus urophylla × Eucalyptus grandis was induced by PBU(patent number: ZL200510035860.X), which is a surface-active new plant growth regulator on plant tissue culture of flower plants and nursery stock in South China. Our research found that the miR166 family expression level increased significantly in the process of Eucalyptus somatic embryogenesis, and showed a close correlation with PBU. In this study, We will study the response mechanism of the upstream hormone response element of miR166 gene to PBU by separating the PBU receptor and its target gene, and find out the biological function of PBU and miR166 gene in the process of somatic embryos occurred in Eucalyptus urophylla× Eucalyptus grandis. With this work, we lay the foundation for the molecular mechanism of somatic embryogenesis of Eucalyptus and to further promote the application of PBU in Eucalyptus micropropagation and somatic embryogenesis.