Genome-wide identification and functional analysis of R2R3-MYB genes in Acer pseudosieboldianum: insights into low temperature stress response and anthocyanin biosynthesis.

The genus Acer pseudosieboldianum, a cold-tolerant maple species native to northeastern China, exhibits remarkable adaptability to extreme winters and vibrant autumn foliage, yet the molecular mechanisms underlying these traits remain poorly characterized. Here, we conducted the first genome-wide identification and functional analysis of the R2R3-MYB transcription factor family in A. pseudosieboldianum to elucidate its roles in cold stress response and anthocyanin biosynthesis. Using a combination of bioinformatic approaches and transcriptomic profiling, we identified 95 ApseMYB genes, classified into 12 subfamilies with conserved motif architectures and structural features. Cis-regulatory element analysis identified 34 genes enriched in low-temperature response motifs, while transcriptomic and qPCR validation highlighted 22 cold-responsive and 14 leaf color-associated ApseMYB genes, including ApseMYB31 (28-fold induction at 4 °C) and ApseMYB16 (52-fold upregulation during leaf reddening). Subcellular localization analysis indicated that ApseMYB31 and ApseMYB16 predominantly localize to the nucleus, consistent with the canonical nuclear activity of R2R3-MYB transcription factors. This study revealed that members of the R2R3-MYB gene family in A. pseudosieboldianum play pivotal roles in mediating both low temperature resistance and leaf anthocyanin accumulation, providing new insights for molecular breeding of cold-tolerant ornamental trees.