Genome-Wide Identification and Expression Analysis of the C3H Gene Family in Betula platyphylla

C3H-type zinc finger proteins play essential roles in plant responses to abiotic stresses, as well as in the regulation of growth, development, and signal transduction. Birch (Betula platyphylla Suk.), an ecologically adaptable tree species widely distributed in northern regions, has not yet been systematically characterized for its C3H gene family. In this study, a total of 15 BpC3Hs were identified from a genome-wide analysis of birch. Their physiochemical properties, gene structures, conserved motifs and domains were systematically analyzed. Promoter analysis identified cis-acting elements associated with stress responses, hormone signaling, and developmental regulation. Transcriptome data further showed that most BpC3Hs were responsive to salt, drought, high/low-temperature stresses, and light/dark treatment, and showed differential expression patterns in tension wood and opposite wood. Additionally, they displayed stage-specific expression patterns during male inflorescence development. This study lays a foundation for future functional characterization of the C3H gene family in birch and its application in molecular breeding for stress resistance.