---

作 者 ：马丽丽;邱丽丽;付扬威;荆瑞瑞;刘雪梅*

期 刊 ：植物研究 2012年 32卷 6期 页码：737-743

关键词：白桦；FT；转录表达；qRTPCR；花发育；突变体；

Keywords:Betula platyphylla, FT, transcription expression, qRT-PCR, flower development, mutant,

摘 要 ：FT及其同源基因在促进植物成花和发育阶段转变过程中起重要作用。应用RT-PCR和RACE技术分离了白桦FT基因的cDNA，全长为928 bp，其开放阅读框为525 bp，编码174个氨基酸。预测的蛋白质分子量为19.6 kDa,理论等电点为7.73。该预测蛋白序列含有保守的PEBP蛋白结构域，命名为BplFT，并在GenBank注册，登录号为JQ409561。该基因序列同其它16种植物的相似性为74%～93%，其中与无花果（Ficus carica）的相似度最高为93%，与拟南芥（Arabidopsis thaliana）的相似度最低为74%，并构建了该基因序列的进化树。通过qRT-PCR的方法检测BplFT基因在白桦不同时期不同组织中的转录表达，在营养器官的表达高于花器官，成熟组织要高于幼嫩的组织，在成熟茎中的表达量最高，推测BplFT基因在成熟的营养器官发育中起重要作用，并可能参与调控次生细胞壁的形成。另外，选择了白桦雄花序突变体进行该基因的转录表达分析，该基因在突变体雌花序、雄花序、幼叶及幼茎中均为上调表达，预示着BplFT基因不仅仅参与营养组织发育，在花器官发育中也具有一定的作用。

Abstract:Flowering Locus T (FT) gene and its homologues play an important role in promotion flowering plants and changes in developmental stage. The full cDNA of FT gene was isolated from Betula platyphylla Suk. by methods of reverse transcription polymerase chain reaction (RT-PCR) and 5′ and 3′ rapid amplification of cDNA ends (RACE). Results showed that FT gene contains an open reading frame (ORF) of 525 bp encoding 174 amino acids. Molecular weight of the deduced protein of BplFT is 19.6 kDa and the theoretical isoelectric point is 7.73. The FT conserved protein domain of PEBP was confirmed in the sequence, so the isolated gene was named as BplFT, and registered in GenBank with accession number JQ409561. The deduced amino acid sequence shared 74%-93% of identity with other sixteen plant species, the maximum identity was with Ficus carica(93%) and minimum identity with Arabidopsis thaliana(74%). A phylogenetic tree was constructed according to multiple sequences alignment of all the seventeen plant species. Transcription expression of BplFT was analyzed by qRT-PCR in different tissues and periods in B.platyphylla. Results showed that BplFT was more highly expressed in vegetative organs than in floral organs, expression quantity was higher in mature tissues than in young tissues, the highest expression is in mature stem. It inferred that BplFT gene play an important role in mature tissues development and transfactor may involved in the formation of secondary cell wall in Betula. In addition, a natural male inflorescence-abnormal mutant of B.platyphylla was used for transcription analysis of BplFT. Results showed that BplFT gene is expressed up-regulatedly in female inflorescences, male inflorescences, young leaves and young shoots, which predicted that BplFT should not only be involved in the development of vegetative tissues, but also play some roles in the development of floral organs.

---