Abstract:

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.

Key words: Populus tomentosa, PtLFY, expression profiling, floral buds, morphological differentiation, qRT-PCR