Abstract:

One important blossom transcription factor SQUMOSA PROMOTER BINDING PROTEIN
LIKE（SPL）was separated and cloned by RT-PCR from the buds on the top of spurs in‘Fuji’apple tree.
The open reading frame of MdSPL6 was 570 bp，encoding a protein of 189 amino acids. Sequence
alignment analysis showed that MdSPL6 shared a highly conserved SBP domain and bipartite nuclear
localization signal（NLS），and it belonged to the SBP family. Additional，there were high homology of
amino acid sequences between MdSPL6 and AtSPL3，AtSPL4，AtSPL5. The results showed that，the
transcription level of MdSPL6 was different among the stem，leaf，flower，fruit and bud，and it showed
higher level in buds and leaves. MdSPL6 was also higher in the buds of‘Yanfu 6’than in‘Changfu 2’. Meanwhile，exogenous GA repressed the expression of MdSPL6 at 40 and 60 DAFB，while showed
upgrade and then descending after exogenous 6-BA treatment. Additional，the expression of MdSPL6
increased after exogenous sugar treatment. MdSPL6 plays important roles in hormone and sugar mediated
flowering，which may be used as a target gene in regulation of apple flower induction.

Key words: apple, flower induction, MdSPL6, clone, gene expression