关键词: 牡丹, 花色, R2R3-MYB基因家族, 生物信息学分析, 花色苷合成调控基因

Abstract: Based on the whole genome data of Paeonia suffruticosa，the R2R3⁃MYB gene family was identified to study its role in the formation of P.suffruticosa flower color and identify key regulatory genes.The physicochemical properties，chromosome location，phylogenetic analysis，gene structure，cis⁃acting elements，expression correlation and protein interaction were analyzed by bioinformatics methods.The expression patterns of genes in P.suffruticosa samples were verified by qRT⁃PCR. A total of 78 R2R3⁃MYB transcription factors of P.suffruticosa were identified，all of which were located in the nucleus and were mostly hydrophilic unstable proteins with abundant cis⁃acting elements and highly conserved R2 and R3 domains at the N⁃terminal.The 78 members were divided into 26 subfamilies（P1—P26）.Among them，Ps2RMYB21，Ps2RMYB38 and Ps2RMYB33 were homologous with S4 and S7，and had conserved motifs specific to the corresponding subfamilies respectively.The expression levels of Ps2RMYB33 and Ps2RMYB38 in normal sepals，colored sepals and normal petals were increased successively，and the expression patterns of structural genes PsCHS，PsCHI3，PsF3H1，PsDFR1，PsANS and PsUFGT4 were the same.There was a significant positive correlation between them，which was consistent with the accumulation trend of anthocyanins.However，Ps2RMYB21 was opposite to the expression pattern of these structural genes，and had a very significant negative correlation with the accumulation trend of anthocyanins.The results of qRT⁃PCR were basically consistent with the transcriptome data.To sum up，Ps2RMYB21，Ps2RMYB33，Ps2RMYB38are three key genes regulating the formation of peony flower color.

Key words: Paeonia suffruticosa, Flower color, R2R3?MYB gene family, Bioinformatics analysis, Anthocyanin synthesis regulatory genes