Genome Identification, Expression Profile Analysis, and Abiotic Stress Response Mechanism of Longan BES1 Gene

BES1 (BRI1 EMS SUPPRESSOR 1) is a critical transcription factor involved in plant growth, development, and stress responses. Although <i>BES1</i> genes have been characterized in several species, their roles in longan (<i>Dimocarpus longan</i> Lour.) remain unclear. This study identified and analyzed eight <i>BES1</i> genes in the longan genome. Phylogenetic analysis classified these genes into four subgroups (I-IV), with conserved motifs and intron-exon structures indicating potential functional similarities within subgroups. Cis-element analysis revealed that the promoters of <i>DlBES1</i> genes contain numerous hormone-related elements, including ABRE, TGACG, and TCA motifs, suggesting their involvement in hormonal signaling and stress responses. Expression profiling showed differential expression patterns of <i>DlBES1</i> genes across nine tissues, with notable up-regulation in roots and seeds. Additionally, <i>DlBES1</i> genes exhibited distinct expression trends under varying temperatures and in response to IAA treatment, indicating potential roles in temperature stress adaptation and hormone signaling. These findings provide novel insights into the regulatory mechanisms of <i>BES1</i> genes in longan and highlight their potential significance in stress tolerance and growth regulation.