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光对园艺植物花青素生物合成的调控作用

花匠小妙招
2024-11-23 05:35

摘要：

花青素是植物中一类重要的类黄酮化合物,在植物花朵、果实等器官色泽形成和抗氧化过程中起着重要作用。植物组织中花青素的形成依赖于光信号,但是光信号对花青素生物合成的调控机制及信号网络很大程度上还不清晰。本文简述了花青素生物合成及运转过程的研究进展,简要归纳了MYB、bHLH、WDR三类主要因子对花青素合成的转录调控作用,重点阐释光信号（光强、光质、光照时长）对植物花青素合成的调控作用。研究表明,光环境（光强、光质、光照时长）主要通过不同的光受体（UVR8、CRYs、PHOTs、PHYs）影响光信号通路重要因子COP1的泛素化能力和HY5的稳定性,以及其他光信号转录因子如光敏色素互作因子PIFs的稳定性,进而调控花青素的生物合成过程。这些光信号因子一方面直接结合到调控花青素合成的MYB、bHLH、WDR三大类转录因子上,转录激活或抑制它们的表达进而调控花青素的合成;另一方面,这些光信号因子通过与MYB、bHLH、WDR三大类转录因子蛋白互作,影响它们形成的MBW复合体稳定性,进而调控花青素的合成。此外,这些光信号因子还可以通过不依赖于MBW复合体的通路调控花青素的合成,如HY5通过调控miR858影响花青素的生物合成;另外,一些未知的光响应因子可能以不依赖MBW通路的方式直接或间接地调控花青素合成基因和液泡膜上的运转蛋白,改变液泡酸化,调节花青素的合成。同时,光信号会影响光合电子传递,光合电子传递链中的一些因子也会通过依赖和不依赖MBW的途径影响植物花青素的合成。这些途径如何协调以及哪些信号因子优先受光环境（光强、光质、光照时间）调控?本文为深入研究光信号对花青素生物合成的调控机理提供参考,以探索光调控花青素积累的有效途径及靶标分子,为利用基因工程、代谢工程和光环境调控手段改良园艺植物花青素积累提供理论基础。

关键词: 光, 花青素, 转录因子, 转录调控, 园艺植物

Abstract:

Anthocyanins are among the most important flavonoid compounds in plants, which play significant roles in color formation of plant organ, such as flower and fruits, as well as antioxidant process. Light is one of the most important environmental factors affecting anthocyanin biosynthesis pathway, but it still remains unclear in the mechanism and signaling networks of light regulation of anthocyanin. This review briefly introduced the anthocyanin biosynthesis and transportation pathway, and summarized the molecular mechanism of anthocyanin transcriptional regulation by three kinds of transcription factors, including MYB, bHLH and WDR. In addition, it emphasized on the light signaling regulation of anthocyanin biosynthesis. The researches showed that the light environment (light intensity, light quality, and light duration) regulated the biosynthetic process of anthocyanin mainly through different light receptors (UVR8, CRYs, PHOTs, and PHYs), which affected the ubiquitination ability of COP1, the stability of HY5, and the stability of other light signal transcription factors, such as the phytochrome-interacting factors (PIFs). On the one hand, these light signal factors directly could bind to the promoters of MYB, bHLH and WDR, activate or inhibit these genes expression and then regulate the synthesis of anthocyanin. On the other hand, these light signal factors interacted with proteins of MYB, bHLH and WDR, affecting the stability of the MBW complex formed by them. In addition, these light signaling factors could also regulate anthocyanin synthesis through MBW independent pathways, such as HY5 also affect anthocyanin biosynthesis by regulating miR858. In addition, some unknown light signaling factors might directly or indirectly regulate anthocyanin synthesis genes and interacting with some vacuolar membranes proteins in a MBW independent manner, to change vacuolar acidification and regulate anthocyanin synthesis. At the same time, light signaling factors also affected some factors in the photosynthetic electron transport chain through MBW dependent or MBW independent pathways, then affected anthocyanin synthesis in plants. How these pathways were coordinated and which pathway was preferentially responded by light environments (light intensity, light quality, light duration)? This paper provided a basis to further investigate the molecular mechanism regulating anthocyanin biosynthesis by light signalings. The study explored the effective ways and target molecules for light regulation of anthocyanin accumulation, and created opportunities for the development of anthocyanin-rich horticultural crops through genetic and metabolic engineering, and light environmental management.

Key words: light, anthocyanins, transcription factor, transcriptional regulation, horticultural crops