Genome-wide characterization of U-box family and their expression profiling with abiotic stress treatment in Populus alba

Abstract

Plant U-box (PUB) E3 ubiquitin ligases are implicated in diverse plant growth, development, and stress responses. However, research on PUB genes in poplar remains limited. In the present work, we conducted comprehensive analysis of the U-box gene family in poplar, investigating molecular physiochemical properties, chromosomal localization, phylogenetic relationships, gene structure, gene tissue specific expression patterns, and gene expression profiles under abiotic stress. A total of 87 PUBs were identified and categorized into seven groups based on phylogenetic analysis. Analysis of gene structure and protein domain revealed that all members possess a typical U-box domain, but variations exist in gene structure and conserved motifs among different groups. Analysis of promoter and tissue specific gene expression demonstrated that PUBs are extensively associated with plant growth, development, and abiotic stress response. Expression profile analysis of seven representative PUBs revealed that they exhibited specific responses to hormone and polyethylene glycol (PEG) treatments. Together, we conducted thorough analysis of the molecular features of poplar PUB family members and their transcriptional responses to abiotic stress, laying groundwork for in-depth exploration of their regulatory role in poplar growth and stress response.