Genome-Wide Comparative Analysis of MYB Transcription Factors in Vitaceae and Expression Profiling Following Powdery Mildew Infection

MYB transcription factors regulate a wide range of developmental, metabolic, and stress-responsive processes in plants.However, the genomic diversity and evolutionary patterns of these factors remain poorly characterized across Vitaceae species.We re-annotated MYB genes in five Vitaceae species (Cissus quadrangularis, Vitis amurensis, V. rotundifolia, V. vinifera, and V. piasezkii) and in Arabidopsis thaliana.A total of 1,891 MYB genes were identified, including 191 newly annotated genes that were missing from existing annotations.Among the identified genes, 1R-MYB and 2R-MYB were the two predominant repeat types, accounting for 51.5% and 46.4% of the total, respectively.A sequence conservation analysis revealed characteristic features of the MYB domain, including three predicted α-helices and highly conserved tryptophan residues, while a motif analysis showed distinct motif compositions between the first and second MYB repeats.A phylogenetic analysis classified the MYB genes into ten subgroups, with lineage-specific differences observed in gene expansion.Expression profiling of V. piasezkii following powdery mildew infection revealed distinct expression patterns among MYB genes.A co-expression network analysis further identified VPIA_67 and VPIA_312 as candidate MYB genes co-expressed with pathogen-response-related genes.These findings provide an updated characterization of MYB transcription factors in Vitaceae and identify candidate genes potentially involved in the powdery mildew response, offering a useful basis for both future functional studies and grape breeding.