关键词: 苹果, 花芽诱导, 赤霉素氧化酶, 基因家族鉴定, 基因表达

Abstract:

In this study，we analyzed the gene structure，chemical characterizations，chromosome locations，evolutionary relationship，promoter cis-acting element，tissue specific expression with online database. Additionally，the expression levels of GA2ox，GA3ox and GA20ox werealso investigatedduring flower induction by qRT-PCR. A total of 41 gibberellin oxidase genes were identified from the apple genome，including 20 GA2ox，14 GA3ox，and 7 GA20ox. They were all distributed on all chromosomes except chromosome 4. The molecular weight is ranged from 13.15 to 60.17 kD，and the isoelectric point is ranged from 5.50 to 9.81. The 41 gibberellin oxidase genes were clustered into five subfamilies. Gene structure and conserved domain analysis showed that the number of exons of the 41 gibberellin oxidase genes were ranged from 1 to 5，and most genes shared conserved motifs 1，5，6，7，and 10. Further，tissue specific analysis by online database showed that the three types of genes were differentially expressed in different varieties and tissues，and their expression levels were relatively high in flowers and fruits. Eight candidate genes were selected for qRT-PCR through the transcriptome data. The expression of GA20ox was down-regulated，while GA2ox was increased at different time after flowering in GA₃ treatment，the expression of GA3ox showed different trends in different stages.

Key words: Malus, flowering induction, GA oxidase, gene family identification, gene expression