柱型苹果开花抑制基因FLOW ERING LOCUS C基因的克隆与表达分析

Cloning and Expression of Md FLC Gene in Columnar Apple(Malus Domestica)

开花抑制基因FLC(FLOWERING LOCUS C)是春化作用中的关键基因,是控制开花时间的枢纽。本研究采用RT-PCR方法,以柱型苹果杂交后代群体中早花株系为试验材料,克隆得到柱型苹果花发育相关基因Md FLC。结果显示,Md FLC开放阅读框长度为603 bp,编码201个氨基酸,推测蛋白质分子量为47.68 k D,等电点为5.18;Md FLC蛋白二级结构包含9个α-螺旋,2个β-折叠区和12个β-转角,具有MADS典型的结构域。系统进化树分析表明,Md FLC与沙梨FLC进化关系最近,与豌豆的亲缘关系最远。半定量PCR及荧光定量PCR分析结果表明,Md FLC基因在普通型苹果‘富士’及柱型苹果株系(95-31,95-41,95-45,95-107,95-152)的花芽和花不同部位(花瓣,花蕊,花萼,花托)均有表达,在柱型苹果花芽、花瓣、花蕊、花萼及花托中的表达量均低于在富士苹果中对应部位的表达量,在花芽中的表达差异尤为显著,暗示了Md FLC基因参与了柱型苹果花芽分化以及开花进程。

Blossom suppressor gene FLC（FLOWERING LOCUS C） is a key gene in the vernalization, which is one of the key genes controlling the blossom time. A c DNA sequence of MADS-box from columnar apple trees was cloned by RT-PCR, named as Md FLC. The Md FLC contains an 603 bp open reading flame（ORF） encoding a deduced protein of 201 amino acids, with the estimated molecular weight and isoelectric point（p I） of the putative protein are 47.68 k D and 5.18, respectively. The secondary structure of predicted Md FLC protein consists of the structures with 9 alpha helixes, 2 beta sheets and 12 beta turns, which would be a conserved MADS-box domain. The phylogenetic tree showed that Md FLC was very closer to pear FLC protein, but the most far to the pea in genetic relationship. Semi-quantitative PCR and quantitative Real-Time PCR revealed that Md FLC mainly expressed in flower buds and different parts of flowers（petals, stamens, calyxes, receptacles） in Fuji apple and columnar apple slections（95-31, 95-41, 95-45, 95-107, 95-152）, but the expression level of Md FLC was higher in Fuji than in those of columnar apple. These results suggest that Md FLC gene be involved in flower bud differentiation and the process of blossom in columnar apple.