瓜叶菊花青素合成关键结构基因的分离及表达分析

Isolation and Expression Analysis of Key Genes Involved in Anthocyanin Biosynthesis of Cineraria

通过RT-PCR的方法分离了花青素合成途径上的关键结构基因片段:CHS、CHI、F3H、F3′H和DFR。在白色系、红色系、紫色系和蓝色系瓜叶菊舌状花中,采用半定量RT-PCR的方法分析CHS、CHI、F3H、F3′H、DFR、F3′5′H、3MaT这7个结构基因在花不同发育阶段的表达模式。结果表明:在白色花中不存在CHS的表达;在红色花中检测到F3′H基因的高丰度表达,但没有检测到F3′5′H的转录本;在蓝色花中没有F3′H表达的信号,但在花序开放的第Ⅰ阶段有较强的F3′5′H的表达信号;而在紫色花中可同时检测到F3′H和F3′5′H的转录本。此外,瓜叶菊花青素合成相关结构基因在花序开放初期高丰度表达,随后逐渐降低,在第Ⅳ阶段表达量再次升高,而在花序开放末期表达量极低或没有表达信号。

To study different structural genes expression pattern in anthocyanin biosynthesis pathway of cineraria with different flower color, internal segments of five structural genes, chalcone synthase （CHS） , chalcone isomerase （CHI） , flavanone 3-hydroxylase （F3H） , flavonoid 3＇-hydroxylase （ F3＇ H） and di- hydroflavonol 4-reductase （DFR） , were isolated from cineraria petals using RT-PCR. Using semi-quantitative reverse transcriptase polymerase chain reaction （RT-PCR）, the expression patterns of CHS, CHI, F3H, F3′H, DFR, flavonoid 3＇, 5＇-hydroxylase （F3′5′H） and anthoeyanin 3-O-glucoside-6＂ -O-malonyltransferase （3MAT） in five developmental stages of cineraria with different flower colors were determined for the first time. The results indicated that there is no CHS transcript in white flowers. In red flowers, F3′H mRNA was expressed at high level. But no F3′5′H transcript was found. F3′5′H was highly expressed in Stage Ⅰ hut no F3′H mRNA was observed in blue flowers. And the transcripts of F3′H and F3′5′H were found in purple pet- als. In addition, these genes were expressed at high level in early stage and underwent moderate decreases in expression. Interestingly, genes expression level increased again in stage Ⅳ. However, in stage Ⅴ, there is little expression level could be detected in petals.