Genome-wide Identification and Expression Analysis of the ADH Gene Family in Tobacco (Nicotiana tabacum L.)

Abstract

Abstract Background Alcohol dehydrogenases (ADHs) are the crucial enzymes involved in plant development, biotic and abiotic stresses. Tobacco is one of the most important model plants, which will be of great application significance to analyze the ADH gene family and expression profile under various stresses in tobacco. Results A total of 53 ADH genes were identified in tobacco (Nicotiana tabacum L.) genome and were grouped into 6 subfamilies based on phylogenetic analysis. Gene structure (exon/intron) and protein motifs were highly conserved among the NtADH genes, especially the members within the same subfamily. A total of 5 gene pairs of tandem duplication, and 3 gene pairs of segmental duplication were identified based on the analysis of gene duplication events. Cis-regulatory elements of the NtADH promoters participated in cell development, plant hormones, environmental stress, and light responsiveness. Expression profile analysis showed that NtADH genes were widely expressed in different maturity tobacco leaves, as well as in leaves after topping, however, the expression patterns of different members appeared to be diversed. The qRT-PCR analysis of 13 NtADH genes confirmed their differential expression in response to the bacterial pathogen Ralstonia solanacearum L. infection. Metabolomics analysis revealed that NtADH genes were primarily associated with carbohydrate metabolism, and moreover, four NtADH genes (NtADH20/24/48/51) were notably involved in the pathway of alpha-linolenic acid metabolism. Conclusion The genome-wide identification, evolutionary and expression analysis of NtADH genes have provided valuable insights into the role of these genes in response to abiotic and biotic stresses. Our results have also laid a solid foundation for further functional study on ADH genes in tobacco, especially for the understanding of NtADHs under more stress conditions.