Plant Secondary Metabolites and Abiotic Stress

Abstract

Plant photoreceptors and transcription factors (TFs), for instance, Elongated Hypocotyl 5 (HY5), are pivotal in orchestrating light-mediated photomorphogenic development. These photoreceptor–TF interaction modules finely regulate light energy capture, crucial for maintaining plant metabolism and facilitating the synthesis of plant secondary metabolites (PSMs). PSMs, a diverse array of small molecules, significantly contribute to plant fitness during various environmental stresses. The intricate regulation of PSM production involves multiple factors, with light as a critical determinant. High light, often accompanied by ultraviolet light, triggers the production of flavonoids and carotenoids. These molecules function as antioxidants, scavenging reactive oxygen species to mitigate photodamage and enhance plant adaptability in diverse environmental conditions. Under light-limiting circumstances, such as shade, the diminished red/far-red light ratio downregulates carotenoid production by binding phytochrome-interacting factor 1 to carotenoid biosynthetic genes. Additionally, shade conditions suppress the accumulation of plant defense metabolites, including soluble phenolics, anthocyanins, and glucosinolates. This regulatory mechanism shapes plant defense strategies, influencing overall fitness in shaded environments. Our current work explores the nuanced interplay between light signaling and PSMs, explicitly focusing on polyphenols, terpenoids, and alkaloids. Also, various aspects of manipulating the light environment to augment PSM production in medicinal plants are discussed. Photoreceptors and TFs emerge as promising targets for engineering stress-tolerant plants, offering valuable insights into plant physiology and adaptive responses. © 2024 Scrivener Publishing LLC. All rights reserved.