Abstract: In order to study the molecular characterization and expression patterns of GA20 oxidase gene in apple dwarfing rootstocks,RT-PCR method was used to clone GA20 oxidase gene (GA20ox1) from cDNA of the apple dwarfing rootstocks No.2 and No.36, and the genes and the amino acid sequences, as well as gene expression on rootstocks and the grafted varieties at various times, was analysed, respectively. Results showed that cDNA of GA20ox1 gene coded a 1 179 bp sequence, and derived a protein with 393 amino acids including termination codon, which the predicted protein molecular weight was 44.3 kDa and theoretical isoelectric point was 5.89.The protein contained conserved domain characteristics of GA20ox1 gene family,and phylogenetic analysis showed that the protein sequence homology with SH40 was at 96.9%. Real-time fluorescent quantitative PCR analysis revealed that the GA20ox1 expression of No.36 rootstock was significantly lower than the control (Malus robusta Rehd.) in June and higher than that in July to August, the expression of the varieties grafted on it was significantly lower than control in July. From July to August, GA20ox1 gene expression levels of No.2 rootstock and the grafted varieties were significantly lower than control.

Key words: Apple dwarfing rootstocks, GA20ox, Cloning, Expression analyses

CLC Number: 

• Q78

• S661.03