Genome-wide identification and expression analysis of the ADH gene family in Artemisia annua L. under UV-B stress

<i>ADHs</i> are key genes that catalyze the interconversion between alcohols and aldehydes, which play crucial roles in plant adaptation to a range of abiotic stresses. However, the characterization and evolutionary pathways of <i>ADH</i> genes in the antimalarial plant <i>Artemisia annua</i> are still unclear. This study identified 49 <i>ADH</i> genes in <i>A. annua</i> and conducted a detailed analysis of their structural features, conserved motifs, and duplication types, revealing that tandem and dispersed duplications are the primary mechanisms of gene expansion. Evolutionary analysis of <i>ADH</i> genes between <i>A. annua</i> (<i>AanADH</i>) and <i>A. argyi</i> (<i>AarADH</i>) revealed dynamic changes, with 35 genes identified deriving from their most recent common ancestor in both species. <i>ADH1</i>, crucial for artemisinin production, had two copies in both species, expanding via dispersed duplication in <i>A. annua</i> but whole-genome duplication in <i>A. argyi</i>. CREs and WGCNA analysis suggested that <i>AanADH</i> genes may be regulated by UV-B stress. Following short-term UV-B treatment, 16 DEGs were identified, including <i>ADH1</i> (<i>AanADH6</i> and <i>AanADH7</i>), and these genes were significantly downregulated after two hours treatment (UV2h) and upregulated after four hours treatment (UV4h). The expression changes of these genes were further confirmed by GO enrichment analysis and qRT-PCR experiments. Overall, this study comprehensively characterized the <i>ADH</i> gene family in <i>A. annua</i> and systematically identified <i>AanADH</i> genes that were responsive to UV-B stress, providing a foundation for further research on their roles in abiotic stress responses.