生物钟PRR蛋白促进拟南芥幼苗中花青素的合成

Circadian clock PRR proteins stimulate anthocyanin synthesis in Arabidopsis thaliana seedlings

关键词:  拟南芥, 生物钟, PRR蛋白, 花青素, MBW复合体

Key words:  Arabidopsis thaliana, circadian clock, PRR protein, anthocyanin, MBW complex

摘要:

生物钟(circadian clock)是激发植物生理特征节律性表达,并使之维持稳定的保守内源调节机制。PRR(PSEUDO-RESPONSE REGULATOR)蛋白家族是生物钟中央振荡器的重要组成部分,调控植物的种子萌发、下胚轴伸长和开花等多种生命过程。花青素(anthocyanin)是植物次生代谢产物,对植物的繁衍、生长发育和抵抗逆境胁迫具有重要作用。该研究以拟南芥(Arabidopsis thaliana)为对象,探讨生物钟PRR蛋白对花青素生物合成的调控功能和分子机制。结果表明:(1)在PRR基因单突变体及多突变体幼苗中,花青素的积累明显降低,某些花青素合成相关基因的表达也显著降低。(2)相反,在PRR5过表达幼苗中,花青素的积累以及某些花青素合成相关基因的表达则显著升高。(3)蛋白相互作用结果显示,PRR5蛋白能与MYB75、TT8、MYB90及MYB113等花青素调控蛋白相互作用,并形成复合物。(4)遗传学分析结果显示,拟南芥PRR5诱导幼苗中花青素的合成依赖于MYB家族花青素调控蛋白。综上认为,生物钟PRR蛋白可能通过PRR5与MYB75、TT8等相互作用,促进拟南芥幼苗中花青素的合成和积累。该研究结果对发掘PRR蛋白新的生物学功能,以及深入理解生物钟信号调控植物幼苗的环境适应性具有重要意义。

Abstract:

The circadian clock is a conservative endogenous regulatory mechanism that stimulates and maintains the rhythmic expression of plant physiological characteristics. The PRR(PSEUDO-RESPONSE REGULATOR)protein family is a critical component of the circadian clock central oscillator and regulates a variety of life processes such as seed germination, hypocotyl elongation, and flowering. Anthocyanin is plant secondary metabolites, which plays an important role in plant reproduction, growth, development and stress responses. In this study, we took Arabidopsis thaliana as the research object and explored the function and mechanism of circadian clock PRR proteins in the control of anthocyanin biosynthesis. The results were as follows:(1)The accumulation of anthocyanin and the expression of some anthocyanin synthesis-related genes were significantly reduced in PRR genes single mutant and multiple mutant seedlings.(2)On the contrary, in the seedlings with overexpression of PRR5, the accumulation of anthocyanin and the expression of some anthocyanin synthesis-related genes were significantly increased.(3)The results of the protein-protein interaction experiment showed that PRR5 protein could interact with MYB75, MYB90, MYB113 and TT8 to form protein complexes.(4)Results of genetic analysis showed that PRR5 promoted anthocyanin synthesis in A. thaliana seedlings depended on the MYB family anthocyanin regulatory proteins. In conclusion, the circadian clock PRR protein may promote the synthesis and accumulation of anthocyanin in A. thaliana seedlings through the interaction of PRR5 protein with MYB75, TT8.