ISOLATION AND EXPRESSION OF ANTHOCYANIN PATHWAY RELATED GENES IN ACTINIDIA

Abstract

Twelve genes related to anthocyanin synthesis were isolated from the red flesh of the kiwifruit cultivar, Actinidia chinensis var. chinensis 'Hongyang', by cDNA and SSH library sequencing and homologue cloning. These genes include partial- or fulllength structural genes, chalcone synthase (CHS), chalcone isomerase (CHI), flavanone 3-hydroxylase (F3H), dihydroflavonol 4-reductase (DFR), leucoanthocyanin deoxygenase (LDOX), UDP-glucose: flavonoid 3-Oglucosyltransferase (UFGT) and UDPG, regulatory genes as myeloblast (MYB) and tryptophan-aspartate (WD) proteins, and transporting proteins such as multidrug resistance-associated proteins(MRP)-like ABC transporters. The isolated AcF3H ORF was 1101 bp in length, which encoded a 366 amino-acid peptide. AcF3H expression level was high before coloration, and then decreased at the early stage. Real-time PCR showed that AcDFR1 expression was extremely high in a greenfleshed cultivar, A. chinensis var. deliciosa 'Jinkui', at anthesis, and remained very high during later development, but was lower in the yellow-fleshed cultivar, A. chinensis var. chinensis 'Jinnong', and the red-fleshed 'Hongyang'. Expression of AcDFR2 was very low at all stages of 'Jinkui', but higher in 'Jinnong' and 'Hongyang'. Nevertheless, transcription levels of AcDFR1 and AcDFR2 increased with fruit coloration of the yellow/red-fleshed cultivars, especially in the later stages of development.