Abstract

Carotenoids are secondary metabolites synthesized in plastids that function in photosynthesis, photoprotection, growth and development of plants. Carotenoids contribute to the yellowish, orange and pinkish-red hues of leaves, flowers and fruits, as well as various aromas. They provide substrates for the biosynthesis of phytohormones and are cleavable into smaller apocarotenoids that function as retrograde signals and/or mediate intracellular communication as well as regulate gene transcription and/or protein translation. Carotenoid biosynthesis and gene regulation are tightly coordinated with tissue-specific plastid differentiation, seedling morphogenesis, fruit development, and prevailing environmental growth conditions such as light, temperature and mycorrhizal interactions. In the last decade, epigenetic processes have been linked to the regulation of carotenoid biosynthesis, accumulation and degradation during plant development. Next-generation sequencing approaches have shed new light on key rate-limiting steps in carotenoid pathways targeted by epigenetic modifications that synchronize carotenoid accumulation with plastid development and morphogenesis. We discuss how histone modifications (methylation and acetylation), DNA methylation and demethylation, as well as small RNA gene silencing processes can modulate carotenoid biosynthesis, accumulation and apocarotenoid generation throughout the plants’ life cycle: from seed germination to fruit morphogenesis. This review highlights how apocarotenoid signals regulate plastid biogenesis and gene expression in sync with chromatin alterations during skotomorphogenesis and photo-morphogenesis. We provide a new perspective based upon emerging evidence that supports a likely role for carotenoids in contributing to the programming and/or maintenance of the plants' epigenetic landscape.

摘要

类胡萝卜素是在质体中合成的次级代谢产物，在植物的光合作用，光保护，生长和发育中起作用。类胡萝卜素有助于叶片，花朵和水果的淡黄色，橙色和粉红色红色色调，以及各种香气。它们为植物激素的生物合成提供底物，并且可裂解为较小的类胡萝卜素，其充当逆行信号和/或介导细胞内通讯以及调节基因转录和/或蛋白质翻译。类胡萝卜素的生物合成和基因调控与组织特异性质体分化，幼苗形态发生，果实发育以及主要的环境生长条件（例如光照，温度和菌根相互作用）紧密协调。在过去的十年中，表观遗传过程已经与植物发育过程中类胡萝卜素的生物合成，积累和降解的调节有关。下一代测序方法为表观遗传修饰靶向类胡萝卜素途径的关键限速步骤提供了新的思路，这些修饰使类胡萝卜素的积累与质体发育和形态发生同步。我们讨论了组蛋白修饰（甲基化和乙酰化），DNA甲基化和去甲基化以及小RNA基因沉默过程如何在植物的整个生命周期中调节类胡萝卜素的生物合成，积累和类胡萝卜素的生成：从种子发芽到果实形态发生。这篇综述强调了类胡萝卜素信号如何在拟态发生和光形态发生期间与染色质变化同步调节质体生物发生和基因表达。我们基于新出现的证据提供了新的观点，这些证据支持类胡萝卜素在促进植物表观遗传景观的编程和/或维持中可能发挥的作用。