FT及其同源基因在植物成花、发育阶段转变等过程中发挥重要作用.为探明苹果FT同源基因的功能和表达规律,从富士苹果中分离了长为598 bp的FT同源基因(MdFT)cDNA序列.序列分析结果表明,该cDNA序列具有完整的开放阅渎框(ORF),推测编码174个氨基酸,与GenBank登录的苹果MdFT2(FJ555224)、苹果MdFTL(AB161112)、桃PpFT(EU939302)、杨树PdFTL(AY515152)和葡萄VvFT(EF157728)基因编码的氨基酸序列的同源性分别为99.4%、93.7%、96.6%、87.4%和89.1%.采用半定量RT-PCR分析苹果MdFT基因在种子、幼果、不同时期的叶片以及花的不同时期、不同部位中的表达水平,结果表明:MdFT基因在种子、幼果、叶以及花中均有表达.在叶片中,MdFT基因的表达量随叶片发育进程呈下降趋势,以3月中旬叶芽中的表达量最高.在种子中MdFT基因表达量较低.在花中,MdFT基因的整体表达量随花的发育进程呈下降趋势,以小蕾期的表达量最高.在花的不同部位中,花药和子房中的表达量高于花瓣、花萼和花丝.由此推测MdFT基因不仅在苹果成花中起作用,还有可能参与花的发育过程.%Flowering locus T (FT) gene and its homologues play important roles in flower development. To investi gate the functions and expression characteristics of FT homologues in Malus × domestica, one of FT homologues was isolatedfrom Fuji apple. The results showed that the eDNA was 598 bp in length, containing a complete open reading frame and en coding 174 amino acids. Compared with FT homologues from other plants, the deduced MdFT protein showed 96.6％,87.4％ and 89.1％ identities with those encoded by FT/FTL of Prunus persica ( PpFT) , Populus detoides (PdFT) and Vi tis vinifera ( VvFT), and 99.4％, 93.7％ with those encoded by MdFT2, MdFTL of Malus ×domestica, respectively. Theexpression pattern of MdFT was studied using semi-quantitative RT-PCR. The results revealed that MdFT was expressed inseed, young fruit, leaf and flower. The expression level in leaf decreased with its development, the level in leafbud in mid March being the highest. In contrast, the level in seed waslower. With the flower development, the expression levelof MdFT declined, the level in small-bud being the high est. The expression level of MdFT was higher in antherand ovary than that in petal, calyx and filament. The a bove results indicate that MdFT can not only promoteblooming, but also play roles in flower development.
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