A comprehensive review of transcription factor-mediated regulation of secondary metabolites in plants under environmental stress

Plants encounter a wide range of biotic and abiotic environmental stresses throughout their lifespan. To adapt and survive, they have evolved complex defense mechanisms that involve the production of secondary metabolites (SMs), which play critical roles in enhancing plant resilience. These bioactive compounds function as deterrents to herbivores, barriers against pathogens, and protectants against oxidative stress. Plants regulate the synthesis and accumulation of secondary metabolites (SMs) in response to various environmental factors such as drought, salinity, cold, heat, heavy metals, and UV-B radiation. These stress conditions can significantly alter SM levels as part of the plant's adaptive response. Transcription factors (TFs) are essential mediators in this process, regulating gene expression involved in SM biosynthesis. By interacting with various signaling pathways, TFs fine-tune the plant's defense mechanisms, ensuring the timely accumulation of specific SMs that mitigate stress impacts. This review provides a comprehensive examination of the influence of environmental factors on SM accumulation in plants under both biotic and abiotic stress conditions. Additionally, we thoroughly discuss the roles of key TFs—including AP2/ERF, WRKY, bHLH, bZIP, MYB, and NAC—in regulating SM biosynthesis, highlighting their contributions to the plant's ability to withstand and adapt to stress.