ADH Gene Cloning and Identification of Flooding-Responsive Genes in Taxodium distichum (L.) Rich.

As a flooding-tolerant tree species, has been utilized in afforestation projects and proven to have important value in flooding areas. Alcohol dehydrogenase (ADH), which participates in ethanol fermentation, is essential for tolerance to the anaerobic conditions caused by flooding. In a comprehensive analysis of the gene family in , were cloned on the basis of whole-genome sequencing, and then bioinformatic analysis, subcellular localization, and gene expression level analysis under flooding were conducted. The results show that the putative protein sequences of 15 cloned genes contained seven and eight genes (one included) that were divided into five clades. All the sequences had an ADH_N domain, and except for , all the other genes had an ADH_zinc_N domain. Moreover, the TdADHs in clades A, B, C, and D had a similar motif composition. Additionally, the number of TdADH amino acids ranged from 277 to 403, with an average of 370.13. Subcellular localization showed that, except for , which was not expressed in the nucleus, the other genes were predominantly expressed in both the nucleus and cytosol. was significantly upregulated in all three organs (roots, stems, and leaves), and was also highly upregulated under 24 h flooding treatment; the two genes might play key roles in ethanol fermentation and flooding tolerance. These findings offer a comprehensive understanding of and could provide a foundation for the molecular breeding of and current research on the molecular mechanisms driving flooding tolerance.