中文摘要：

以毛白杨花芽为材料,采用RT-PCR技术分离克隆毛白杨PtLFYcDNA序列,测序结果表明该序列全长1314bp,包含1个开放阅读框,编码377个氨基酸。Alignment分析显示该基因与拟南芥等物种LFY/FLO同源基因所编码的氨基酸相似性达到68%～75%。蛋白结构预测分析表明,在PtLFY蛋白N-端和C-端具有2个高度保守的区域,其中PtLFY-C端由7个α-helix组成Helix-turn-helix结构。采用Real-time qRT-PCR技术检测PtLFY在雌雄花芽发育过程中的表达模式,结果显示从9月13日到翌年1月25日,PtLFY在毛白杨雌雄花芽中持续稳定表达,到2月25日表达量少许下调,但该基因在雄花芽中的相对表达量明显高于雌花芽。解剖分析结果表明,雄花芽形态分化进程明显早于雌花芽,这种差异可能与PtLFY在雌雄花芽发育过程的差异表达存在密切联系。研究结果对于阐明PtLFY在毛白杨雌雄花芽发育和开花中的分子作用机制具有重要的理论意义,为进一步开展毛白杨开花调控研究奠定基础。

英文摘要：

A full-length cDNA denominated PtLFY was obtained from Populus tomentosa using RT-PCR technique. PtLFY is 1 314 bp and contains an open reading frame encoding a 377 amino acid polypeptide. Sequence analysis by blast showed that PtLFY shares 68%-75% homology in amino acid sequence with that encoded by Arobidopsis LFY and other species LFY/FLO homologues. It was found that PtLFY protein contains 2 conserved domains at N-terminal and C-terminal by alignment analysis. PtLFY-C region consists of a seven-α helix fold structure that binds target promoter DNA elements. The expression patterns of PtLFY in developmental floral buds were examined using real-time quantitative RT-PCR. The result showed that the continuous and stable transcripts of PtLFY were detected in both male and female floral buds of P.tomentosa from September 13th to January 25th,and then a slight decline was detected on February 25th. The relative expression of PtLFY in male floral buds was obviously much higher than that in female floral buds. The anatomical results showed that initiation and differentiation of male floral buds were obviously earlier than female floral buds. It revealed that there is close relationship between expression of PtLFY and morphological differentiation of floral buds in P.tomentosa. This study shed light on the molecular mechanism of PtLFY in development of both male and female floral buds and flowering in P.tomentosa,and the knowledge will benefit regulation of flowering.