Identification of PEBP Gene Family in Gossypium arboreum and Gossypium raimondii and Expression Analysis of the Gene Family in Gossypium hirsutum

Abstract

The phosphatidylethanolamine-binding proteins(PEBP) widely exist in eukaryotes. In angiosperms, PEBP family genes play important role in promoting or inhibiting flowering, as well as plant architecture control. Eight PEBP genes were identified from diploid cotton Gossypium arboreum(A2) and Gossypium raimondii(D5) genome database, respectively. All the PEBP genes of cotton contained four exons and three introns, and their encoded proteins contained a conserved PEBP motif and critical amino acid sites of PEBP family, which indicated there were at least eight PEBP genes in diploid cotton. Phylogenetic analysis showed that eight cotton PEBP genes comprised three subfamilies: FLOWERING LOCUS T(FT)-like containing one gene, TERMINAL FLOWER 1(TFL1)-like containing five genes including three TFL1 and two BFT genes, and MOTHER OF FT AND TFL1(MFT)-like containing two genes. The expression patterns of eight Gossypium hirsutum PEBP family genes in root, stem, leaf, shoot apical meristem, flower, ovule and 25 days post-anthesis(DPA) fiber were determined with quantitative Real-time reverse transcription PCR(q RT-PCR). The results showed that FT1 transcript was preferentially expressed in leaf and secondly in fiber, ovule and flower. MFT1 expressed in all the tissues, with the highest expression level in fiber, then in flower and leaf, while MFT2 transcript was preferentially expressed in leaf. TFL1 a, TFL1 b, and TFL1 c expressed mainly in root, and TFL1 c also expressed in leaf, flower and ovule. Expression of BFT1 and BFT2 were present mainly in leaf, and that of BFT1 in the other six tissues except for shoot apical meristem(SAM) were higher than that of BFT2. Expression analysis revealed that eight PEBP genes in cotton have different expression patterns, showing their different functional roles in regulation of cotton development.