MYB transcription factors in plant cold stress adaptation: integrating phylogeny, signaling networks, and metabolic regulation
MYB transcription factors are pivotal regulators of plant cold acclimation, yet current knowledge about cold-tolerance-related MYBs (crMYBs) remains fragmented across species, with their phylogenetic relationships, regulatory mechanisms, and functional divergence poorly integrated. This review synthesizes functionally validated crMYBs within a phylogenetic framework to provide an updated perspective on their regulatory roles in plant cold acclimation. We curated 106 experimentally validated crMYBs from 45 plant species and systematically characterized their subfamily distribution, regulatory polarity, pathway associations, validation strategies, and cross-species functional patterns. R2R3-MYBs constitute the majority of characterized crMYBs, whereas 1R-MYBs and 3R-MYBs remain underrepresented despite their established links to circadian regulation, cell-cycle control, and stress adaptation. Comparative analyses further indicate that orthologous MYBs retain conserved functions or undergo functional divergence across species. Current evidence implicates crMYBs in multiple regulatory layers of cold acclimation, including ABA-associated responses, CBF/COR-related transcriptional regulation, hormonal crosstalk, osmoprotectant accumulation, phenylpropanoid metabolism, cuticular wax biosynthesis, post-translational modifications, and chromatin-level regulation. Characterization of underexplored 1R-MYB and 3R-MYB members, phylogeny-guided cross-species functional validation, clarification of the mechanisms underlying regulatory polarity divergence, and evaluation of MYB functions under combined stress conditions would contribute substantially to a more comprehensive understanding of plant cold resilience.