关键词: 苹果, 基因, LEAFY, 克隆, 表达

Abstract: Two LEAFY like cDNA fragments of in length，AFL1 and AFL2 were cloned from the terminal buds of bearing shoot of apple trees．Sequencing analysis showed that the coding regions of AFL1 and AFL2 had 90% homolegy，but the 3’non-coding regions had less than 60% homology．The deduced amino acid sequence of AFL1 or AFL2 cDNA had over 70% similarity with PTFL ， PEAFLO and ALF genes of poplar、pea and petunia， and less than 70% similarity with TOFL， FLO and LFY genes of tomato， antirrhinum majus and arabidopsis respectivehy. RT-PCR analysis showed that AFL1 expressed only in the telminal buds during the transition period from vegetative to reproductive growth; whereas AFL2 expressed in the sepal, ovary, root, stem, leaf and the terminal buds between June to Oct. These results might suggest that AFL1 and AFL2 had a common origin， and their functions had diverged， so that they appeared to play independent roles inⅡ0Ial and vegetative tissue development．Southem blot analysis showed that there were at least two copies of LEAFY homo logues genes in Malus species and pear.

Key words: Apple, Gene, LEAFY, Cloning, Expression