关键词: 苹果, 生长素, MdARF3, 花青苷, 原核表达

Abstract:

The red-callus induced from the leaves of‘Zihong 3’apple in an F₁ population of Malus sieversii f. niedzwetzkyana crossed with‘Fuji’was used as materials. An auxin signal relative gene （MDP0000173151）was obtained from apple genome by BLAST searches of the Arabidopsis AtARF3 protein sequence，designate MdARF3. Sequence analysis indicated that the open reading frame（ORF） length of MdARF3 was 2 127 bp，which encoded 708 amino acids. Phylogenetic analysis revealed that MdARF3 was homologous with AtARF3 which was involved in the auxin signaling. Compared with the NAA-deprived callus（the control），the transcript level of MdARF3significantly higher was on the MS medium contained 0.3 mg · L^-1 NAA after 2 hours. In contrast，the expression levels of anthocyanin biosynthesis structural genes（CHS，CHI，F3H，DFR，UFGT and LDOX）were lower on the MS medium contained 0.3 mg · L^-1 NAA. At the 0.05 level，the expression of MdARF3 was positively correlated with the auxin concentration（correlation coefficient 0.98）and was negatively correlated with the anthocyanin content （correlation coefficient–0.89） of callus. Therefore，the MdARF3 is supposed to be an auxin-responsive transcription factor to regulate the biosynthesis of anthocyanin in apple. The recombinant protein of MdARF3 was obtained by the prokaryotic expression technique，which laid a foundation for functional identification of MdARF3 associated with anthocyanin metabolism.

Key words: Malus × domestica, auxin；MdARF3, anthocyanin, prokaryotic expression