Genome-Wide Identification, Phylogenetic Analysis and Salt-Responsive Expression Profiling of the MYB Transcription...

Seed germination is a critical developmental stage exhibiting high vulnerability to salt stress. The role of MYB transcription factors (TFs) in mediating this process in Cannabis sativa L. remains largely unexplored. In this study, we performed a genome-wide analysis and identified 115 CsMYB genes, which were phylogenetically classified into 12 distinct subgroups. In silico promoter analysis revealed a significant enrichment of abscisic acid (ABA)- and methyl jasmonate (MeJA)-responsive cis-elements, suggesting their potential linkage to phytohormone signaling pathways under stress conditions. To investigate their expression during salt stress, we profiled a subset of candidate CsMYB genes during seed germination under 150 mM NaCl treatment based on RNA-seq screening at 24 h post-imbibition (hpi) under salt stress. These candidates exhibited distinct temporal expression profiles: CsMYB33 and CsMYB44 were transiently induced at the early stage (12 h post-imbibition), while CsMYB14, CsMYB78, and CsMYB79 showed sustained upregulation from 24 h to 5 days. In contrast, CsMYB58 and CsMYB110 were downregulated. Synteny analysis indicated a closer evolutionary relationship between CsMYBs and their Arabidopsis thaliana orthologs compared to those in monocots. Protein-protein interaction predictions, based on orthology, further implicated these CsMYBs within putative ABA signaling and reactive oxygen species (ROS) homeostasis networks. Collectively, our findings provide a systematic genomic identification and genomic characterization of the CsMYB family and propose a model for the potential multi-phase involvement of selected CsMYBs in the salt stress response during seed germination. This work establishes a foundational resource and identifies key candidate genes for future functional validation aimed at enhancing salt tolerance in C. sativa.