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

摘要： 基于牡丹全基因组数据对R2R3-MYB基因家族进行鉴定，研究其在牡丹花色形成中的作用，确定关键调控基因。利用生物信息学方法进行理化性质、染色体定位、系统进化、基因结构、顺式作用元件、表达相关性及蛋白质互作分析，并通过qRT-PCR验证基因在牡丹样品中的表达模式。结果表明，共鉴定出78个牡丹R2R3-MYB转录因子，均位于细胞核，多为亲水性的不稳定蛋白，具有丰富的顺式作用元件以及N端高度保守的R2、R3结构域。系统进化将78个成员分为26个亚族（P1—P26），其中牡丹Ps2RMYB21、Ps2RMYB38和Ps2RMYB33分别与已知调控花色苷合成的拟南芥S4、S7同亚族，具有对应亚族特有的保守基序。Ps2RMYB33、Ps2RMYB38在正常萼片、彩色萼片、正常花瓣中的表达量依次升高，与结构基因PsCHS、PsCHI3、PsF3H1、PsDFR1、PsANS、PsUFGT4 表达模式相同，表现为极显著的正相关性，与花色苷积累趋势一致。Ps2RMYB21与上述结构基因的表达模式相反，呈极显著负相关性，与花色苷积累趋势相反。qRT-PCR 验证结果与转录组数据基本一致。综上，Ps2RMYB21、Ps2RMYB33、Ps2RMYB38是调控牡丹花色形成的3个关键基因。

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