光皮桦BlFTL基因的克隆和表达模式

Cloning and expression analysis of BlFTL in Betula luminifera

通过反转录-聚合酶链式反应（RT-PCR）结合如cDNA末端快速克隆（RACE）技术从光皮桦Betula luminifera中克隆到1个FT类似基因,命名为BlFTL。该基因cDNA全长为924 bp（GenBank登录号：JQ951966）,包含1个525bp的开放阅读框（116~640 bp）,编码1个含174个氨基酸的蛋白,且具有FT蛋白典型的磷脂酰乙醇胺结合蛋白（PEBP）结构域。与已有部分植物中FT蛋白同源比对结果显示,BlFTL与无花果Ficus carica中FcFT序列相似性最高,达到了94%。4月为光皮桦开花期,雌花中BlFTL基因的表达量最高,茎和叶片中表达量很低。比较正常开花和不开花无性系植株嫩茎和叶片在不同时间BlFTL基因的表达情况,结果表明：BlFTL在不开花无性系植株中基本不表达,而正常开花植株中,BlFTL主要在雌花序和混合芽形成的8月以后表达。

Flowering Locus T （FT） gene plays a crucial role in flower formation of plants. To clarify the function of FT-like genes in Betula luminifera will be helpful to learning about the mechanism of flowering formation in woody plant. The reverse transcription polymerase chain reaction （RT-PCR） and rapid amplification of cDNA ends （RACE） methods were used to clone a Flowering Locus T （FT）-like homolog （named BlFTL） from Betula luminifera （FT）-like）. Sequence analysis with show translations software showed that the full length of B1FTL cDNA was 924 bp and contained a single open reading frame （116-640 bp） encoding a protein of 174 amino acids （GenBank NO. JQ951966）. The B1FTL protein had a typical phosphatidyl ethanolamine-binding protein （PEBP） domain which was an important characterization of the FT family protein. Alignment FT protein sequence in different plants showed that the B1FTL protein shared a 94% similarity with the Ficus carica flow ering locus T protein （FcFT）. Also, during flowering in April, the expression of BIFTL in female flowers was almost 50 folds higher than in male flowers. In addition, in normal flowering plants after August, with the formation of the male inflorescence and mixed buds, BlFTL expressed highly in leaves in flowering plants, but no expression in non-flowering plants. In stems, the expression of B1FTL of flowering plants was 6 folds higher than in non-flowering plants. These results inferred that BlFTL was involved in flower formation of Betula luminifera. [Ch, 8 fig. 13 ref.]