Genome-wide characterization of the 2OGD-Hs gene family in apple reveals a GA-metabolic gene, MdGA2ox1b, confers stress tolerance via MdHY5 regulation
Year: 2026
Type: article
Abstract: Introduction The 2-oxoglutarate/Fe(II)-dependent dioxygenase hormone-related subfamily (2OGD-H), a key branch of the 2OGD superfamily, plays a crucial role in plant growth, development, stress adaptation and in the biosynthesis and metabolic regulation of phytohormones. However, despite functional studies of several individual 2OGD-H genes in apple ( Malus domestica ), a comprehensive genome-wide identification and systematic characterization of this subfamily remains lacking. Methods In this study, we systematically identified 2OGD family members in the apple genome using conserved domain searches and phylogenetic analyses. Gene duplication, promoter cis-elements, and transcriptomic expression patterns were analyzed. The candidate gene MdGA2ox1b was functionally validated via overexpression/silencing in apple calli under salt, cold, and heat stress conditions. The direct regulatory relationship with the upstream transcription factor MdHY5 was verified using yeast one-hybrid, EMSA, GUS, and dual-luciferase assays. Results This current study systematically identified 257 members of the 2OGD family in apple designated as Md2OGDs, which also included 58 Md2OGD-Hs . The Md2OGD-Hs were classified into nine evolutionary clades based on their conserved 2OG-FeII_Oxy and DIOX_N domains as well as clade-specific motifs. The study also showed that the Md2OGD-Hs expanded primarily from the whole-genome duplication events, and were closely related to 2OGD-Hs in grapes ( Vitis vinifera ) than in rice ( Oryza sativa ). The Md2OGD-Hs consisted of 23 types of cis-acting elements associated with light responsiveness, hormone signaling, and stress adaptation, suggesting a multidimensional regulatory network in these genes. The transcriptomic data also demonstrated the broad regulatory roles of Md2OGD-Hs in apple tissue development, with 26 genes notably linked to fruit ripening. Through integrated analysis of multiple abiotic stress transcriptomes, we showed that MdGA2ox1b gene responds to various abiotic stresses and resides in the cytoplasm and nucleus, with a weak expression in the roots and high expression in the flowers. This gene also significantly enhances tolerance to salt, cold and heat stress in apple calli by activating antioxidant enzymes. MdHY5 directly bound its promoter and activated its expression, especially under cold stress. Discussion This study elucidates the evolutionary dynamics and biological roles of Md2OGD-Hs , and provides a theoretical foundation and genetic resources for unravelling molecular mechanisms underlying stress resistance in apple.
Source: Frontiers in Plant Science
Authors: Shuangxun Ma, Danni Zhang, Chao Yang
Institutions: Chang'an University, Northwest A&F University
Language: English
Subfield: Plant Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: gold
Estimated APC paid: $3,801
Award: G1238733024
OpenAlex ID: W7222249403