Genome-wide analysis of the MYB-related transcription factor family and associated responses to abiotic stressors in Populus.

MYB proteins are one of the most abundant transcription factor families in the plant kingdom. Evidence has increasingly revealed that MYB-related proteins function in diverse plant biological processes. However, little is known about the genome-wide characterization and functions of MYB-related proteins in Populus, an important model and commercial tree species. In this study, 152 PtrMYBRs were identified and unevenly located on 19 Populus chromosomes. A phylogenetic analysis divided them into six major subgroups, supported by conserved gene organization, consensus motifs, and protein domain architecture. Promoter assessment and gene ontology classification results indicated that the MYB-related family is likely involved in plant development and responses to various environmental stressors. The Populus MYB-related family members showed various expression patterns in different tissues and stress conditions, implying their crucial roles in the development and stress responses in Populus. Co-expression analyses revealed that Populus MYB-related genes might participate in the regulation of antioxidant defense system and various signaling pathways in response to stress. The three-dimensional structures of different subgroup of Populus MYB-related proteins further provided functional information at the proteomic level. These findings provide valuable information for a prospective functional dissection of MYB-related proteins and genetic improvement of Populus.