Abstract

Three R2R3-MYB genes, designated CaMYB1, CaMYB2 and CaMYB3, were isolated from hot pepper (Capsicum annuum. L). CaMYB1, CaMYB2 and CaMYB3encode polypetides consisting of 340, 262 and 345 amino acids respectively, containing R2R3 domain and the signature motif specific for the interaction between MYB and bHLH proteins in the R3 domain. Phylogenetic analysis based on the deduced amino acid sequences of these three R2R3 MYB transcription factor members revealed that CaMYB1 and CaMYB2 clustered together with the anthocyanin-related subgroup of R2R3 MYB proteins from other plants, while CaMYB3 did not. CaMYBs transcripts accumulation was detected in all stages of fruit development and in flower and leaves. Three CaMYBs transcription factors showed differential expression during fruit ripening. Anthocyanin biosynthetic gene expression patterns were quite different in young leaves, flower, and the four stages of fruit development. CaMYB1 and CaMYB2 may regulate anthocyanin biosynthesis in hot pepper.

Key words: Anthocyanin, Capsicum annuum, gene expression, R2R3 MYB transcription factor.

Abbreviation

ANS, Anthocyanidin synthase; bHLH, basic-helix-loop-helix; CHI,chalcone isomerase; CHS, chalcone synthase; DFR, dihydroxavonol 4-reductase;F3H, flavanone 3-hydroxylase; ORF, open reading frame; RACE, rapid amplification of cDNA ends; RT-PCR, reverse transcriptase polymerase chain reaction; UFGT,UDP-glucose:flavonoid 3-O-glucosyltransferase; UTR, untranslated region.