Molecular mechanisms and application potential of MYC2 transcription factor-mediated plant stress responses.

Abstract

Plant adaptation to drought, salinity, temperature extremes, pathogens, and herbivorous insects depends on coordinated hormone signalling, transcriptional control, and metabolic reprogramming. The jasmonic acid (JA) pathway is a major regulator of defence and the growth-defence trade-off, and the bHLH transcription factor MYC2 is a central node in JA output. Mechanistically, MYC2 is controlled through demonstrated protein-protein interactions with JAZ repressors, MED25, and selected transcriptional or chromatin regulators; it binds G-box-related cis-elements to regulate specific promoters, whereas many reported links to LOX/AOS, CBF, and antioxidant pathways are transcriptional or pathway-level rather than physical interactions. This integrative narrative review compares MYC2 orthologues across species, distinguishes MYC2-specific functions from those shared with MYC3/MYC4 or other clade IIIe bHLHs, and organises beneficial and detrimental stress phenotypes around pathogen lifestyle, target-gene polarity, tissue and developmental context, paralogue redundancy, and experimental design. We integrate genome-wide DNA-binding, transcriptomic, metabolomic, and protein-level studies, and critically evaluate demonstrated versus prospective applications of CRISPR/Cas genome editing. The synthesis identifies regulatory strategies that may exploit MYC2 networks whilst limiting growth, defence, and quality trade-offs.