菊花‘千手观音’LEAFY基因转录区基因组克隆和结构分析

LEAFY(LFY)基因在植物花发育过程中具有重要作用，不仅控制着花序分生组织向花分生组织的转变，而且控制着开花时间.通过基因组PCR扩增，获得了菊花‘千手观音’LFY同源基因序列.序列分析表明该基因包括2个内含子和3个外显子.其内含子1的2个序列长短不同，差异明显.2个内含子与甘菊的LFY同源基因DFL相比都表现出了丰富的变异性.其外显子推测的氨基酸序列与甘菊DFL的氨基酸序列相似性达99%.系统进化分析表明‘千手观音’的LFY同源基因与所有的菊属植物的LFY基因在树的同一枝上，且距双子叶植物的距离近于单子叶或裸子植物.Southern杂交表明，‘千手观音’基因组中LFY同源基因以两个拷贝形式存在.

Cloning and Structure Analysis of LEAFY Homologues of Genomic Sequence Isolated from Chrysanthemum morifolium 'Qianshouguanyin'

LEAFY(LFY) plays an important role in the process of flower development. Not only does it control the transition of the inflorescence meristem to floral meristem， but also controls the flowering time. In this study， the LFY homologue was cloned from Chrysanthemum morifolium ‘Qianshouguanyin’ based on the genomic PCR. The sequences analysis shows that the genomic sequence contains three exons and two introns. There are two different structures in intron 1. The two introns of this gene have high variability in their sequence comparing with the DFL gene isolated from Dendranthema lavandulifolium. The putative protein of this gene is 99% identical to the DFL. The phylogenetic analysis reveals that the LFY protein of ‘Qianshouguanyin’ is more closed to dicotyledon FLO/LFY like than to monocotyledon or to gymnosperm. Southern blot hybridization results indicate that LFY homologue of ‘Qianshouguanyin’ has two copies in its genomes.