‘凤丹’牡丹花色变化过程中花瓣色素及相关基因表达

Analysis of Petal Pigment and Related Gene Expression During Flower Color Change of Paeonia ostii‘feng dan’

针对‘凤丹’牡丹在开放过程中花色由紫红色变白的现象,以‘凤丹’5个不同开放时期的花瓣为试验材料,分别运用色差仪、高效液相色谱仪和荧光定量PCR测定花色表型、花色素成分及质量分数和花青苷合成途径中相关基因的表达,进而分析花瓣色素与花青苷合成相关基因表达之间的关系。结果表明:随着花的开放,红色大幅减退,明度变大,彩度降低;‘凤丹’花中检测出2种花青苷(芍药花素-3,5-二葡糖苷和矢车菊素-3,5-二葡糖苷)和8种单体酚。花开放过程中,总花青苷和总黄酮质量分数逐渐减少,总花青苷质量分数降低幅度更大。花青苷合成相关结构基因PAL、DFR、ANS和转录因子MYB22、bHLH1的表达模式与总花青苷质量分数的变化趋势一致,而且这些基因的表达量与总花青苷质量分数均具有极显著正相关性。研究发现,‘凤丹’花色变化的主要原因是总花青苷质量分数大量减少。PAL、DFR、ANS是参与‘凤丹’花青苷合成的关键结构基因,转录因子MYB22及bHLH1可能对结构基因DFR和ANS的表达起着重要的调控作用。

For the fact that the flower color of the Paeonia ostii‘feng dan’turns from purple to white during flowering,we measured the floral color phenotype,petal pigment composition and content,and expression of related genes in anthocyanin synthesis pathway during five flowering stages in the petals of P.ostii‘feng dan’.They were determined by colorimeter,high performance liquid chromatography and quantitative real-time PCR,respectively.We analyzed the relationships between pigments and anthocyanin biosynthesis genes.The redness of floral color greatly decreased,the lightness increased and the chroma decreased during flowering.Two anthocyanins(cyanidin-3,5-di-O-glucoside and peonidin-3,5-di-O-glucoside)and eight mono-phenols were detected.The contents of total anthocyanins and total flavonols were decreased sharply,and the total anthocyanins content decreased sharper.The expression patterns of anthocyanin biosynthetic structural genes PAL,DFR,ANS and transcription factors(regulation genes)MYB22 and bHLH1 were consistent with the changes in total anthocyanins content.And these genes expression had extremely significant positive correlations with the total anthocyanins content.The flower color change is mainly due to a significant decrease in total anthocyanins content.PAL,DFR and ANS are key structural genes in anthocyanin synthesis pathway of P.ostii‘feng dan’.The transcription factors MYB22 and bHLH1 may play important regulatory roles in the expression of the structural genes DFR and ANS.