陆地棉编码成花素同源基因GhFT1-A和GhFT1-D启动子的克隆及活性分析

Cloning and activity analysis of the promoters of FT1 homoeologs, GhFT1-A and GhFT1-D encoding the florigen from Gossypium hirsutum L.

在陆地棉全基因组中序列比对GhFT1基因在At和Dt基因组上的差异,设计特异性引物克隆其上游约1.8 kb的非编码序列作为目的启动子,通过测序结果区分At、Dt类型。本研究克隆出1701 kb GhFT1-A启动子和1771 kb GhFT1-D启动子(简称1.8 kb)。序列比对分析发现了At和Dt基因组上不同GhFT1启动子间存在许多核苷酸序列差异。GhFT1-A和GhFT1-D启动子上存在大量的、作用广泛的顺式作用元件,并发现了一个顺式作用元件富集的重复片段区域。启动子活性检测证明了GhFT1基因上游1.8 kb的At和Dt启动子均具有活性,但At亚基因组启动子的活性弱于Dt型。陆地棉编码成花素同源基因GhFT1的启动子对于调控GhFT1-A和GhFT1-D的表达具有重要作用,并且它们之间的活性存在差异,暗示At和Dt基因组对开花调控作用不同。

The upstream sequences of GhFT1-A and GhFT1-D were obtained by BLAST againstupland cotton genome using GhFT1 gene as query, and their genomic sequences were cloned by PCR using specific primers. In this study, we obtained the genomic sequences of promoters of GhFT1-A and GhFT1-D homoeologs from Gossypium hirsutum L. cv. XLZ 42 which were1,701 bp and 1,771 bp lengths, respectively. In both promoters, we had predicted lots of cis-acting elements which function in a wide range. Moreover, there was a region containing a number of repeated sequences and abundant cis-acting elements in GhFT1-A or GhFT1-D promoter respectively. Sequences alignment showed that a lot of nucleotide differences exist between these two promoters. Promoters activity analyses showed that both promoters he different activities, and the activity of 1,701 bp GhFT1-A promoter was weaker than 1,771 bp GhFT1-D promoter. 1.8 kb length genomic sequences of the upstream of GhFT1-A and GhFT1-D play important roles in regulating the expression of GhFT1 genes, whereas At and Dt subgenome promoters have differential activities, suggesting their different effects on flowering regulation.