Genome-wide identification of 2-oxoglutarate and Fe (II)-dependent dioxygenase family genes and their expression profiling under drought and salt stress in potato

The 2-Oxoglutatrate-dependent dioxygenases (2OGDs) comprise the 2-Oxoglutatrate and Fe(II)-dependent dioxygenases (2ODD) enzyme families that facilitate the biosynthesis of various compounds like gibberellin, ethylene, etc. The 2OGDs are also involved in various catabolism pathways, such as auxin and salicylic acid catabolism. Despite their important roles, 2ODDs have not been studied in potato, which is the third most important crop globally. In this study, a comprehensive genome wide analysis was done to identify all 2ODDs in potatoes, and the putative genes were analysed for the presence of the signature 2OG-FeII_Oxy (PF03171) domain and the conserved DIOX_N (PF14226) domain. A total of 205 St2ODDs were identified and classified into eight groups based on their function. The physiochemical properties, gene structures, and motifs were analysed, and gene duplication events were also searched for St2ODDs. The active amino acid residues responsible for binding with 2-oxoglutarate and Fe (II) were conserved throughout the St2ODDs. The three-dimensional (3D) structures of the representative members of flavanol synthase (FNS), 1-aminocyclopropane-1-carboxylic acid oxidases (ACOs), and gibberellin oxidases (GAOXs) were made and docked with their respective substrates, and the potential interactions were visualised. The expression patterns of the St2ODDs under abiotic stressors such as heat, salt, and drought were also analysed. We found altered expression levels of St2ODDs under abiotic stress conditions, which was further confirmed for drought and salt stress using qRT-PCR. The expression levels of St2ODD115, St2ODD34, and St2ODD99 were found to be upregulated in drought stress with 2.2, 1.8, and 2.6 fold changes, respectively. After rewatering, the expression levels were normal. In salt stress, the expression levels of St2ODD151, St2ODD76, St2ODD91, and St2ODD34 were found to be upregulated after 24 hours (h), 48 hours (h), 72 hours (h), and 96 hours (h). Altogether, the elevated expression levels suggest the importance of St2ODDs under abiotic stresses, i.e., drought and salt. Overall, our study provided a knowledge base for the 2ODD gene family in potato, which can be used further to study the important roles of 2ODDs in potato plants.