Genome-Wide Identification and Characterization of the BZR Transcription Factor Gene Family in Leymus chinensis

Background/Objectives: The BZR gene family, a critical transcription factor in the brassinosteroid (BR) signaling pathway, regulates plant growth and development. Despite its significance, the BZR gene family in Leymus chinensis, a valuable forage grass renowned for its stress tolerance and nutritional quality, remains uncharacterized, and its functional roles are largely unexplored. Methods: Employing advanced bioinformatics tools, we conducted a genome-wide survey to identify members of the BZR gene family in L. chinensis. Phylogenetic analyses were performed to classify these genes into distinct clades, while gene structure and conserved motif analyses assessed their evolutionary conservation and potential regulatory mechanisms. Additionally, transcriptome sequencing was utilized to examine the expression patterns of BZR genes in response to simulated animal grazing. Results: Eight LcBZR genes were identified, evenly distributed across all seven chromosomes. Phylogenetic analysis categorized these genes into three distinct groups, reflecting their evolutionary relationships. Most LcBZR genes exhibited highly conserved gene structures and motifs, with promoters enriched in cis-acting elements such as G-box and ARE. Expression profiling revealed that LcBZR genes are predominantly expressed in key tissues, particularly leaves and roots, suggesting their involvement in critical physiological processes. Transcriptomic analysis demonstrated that simulated animal grazing modulated the expression levels of LcBZR genes, implicating their role in promoting cellular elongation and division through the BR signaling pathway. Conclusions: This study highlights the crucial role of LcBZR genes in regulating plant growth, development, and response to environmental stimuli, providing a foundational basis for understanding the molecular mechanisms of BR-mediated plant development and stress adaptation.