Genome-Wide Identification, Evolution, and Expression Analysis of the Gene Family in .

, commonly known as the Chinese guger tree, is highly adaptable and tolerant of poor soil conditions. It is one of the primary species forming the evergreen broad-leaved forests in southern China. Dirigent proteins (DIRs) play crucial roles in the synthesis of plant lignin and lignans, secondary metabolism, and response to adversity stress. However, research on the gene family in is currently limited. This study identified 24 genes, categorizing them into three subfamilies. These genes are unevenly distributed across 13 chromosomes, with 83% being intronless. Collinearity analysis indicated that tandem duplication played a more significant role in the expansion of the gene family compared to segmental duplication. Additionally, we analyzed the expression patterns of in different tissues of . The genes exhibited distinct expression patterns across various tissues, with most being specifically expressed in the roots. Further screening identified genes that may regulate drought stress, with many showing differential expression under drought stress conditions. In the promoter regions of s, various cis-regulatory elements involved in developmental regulation, hormone response, and stress response were identified, which may be closely related to their diverse regulatory functions. This study will contribute to the further functional identification of genes, providing insights into the biosynthetic pathways of lignin and lignans and the mechanisms of plant stress resistance.