Comprehensive analysis of the SmATL gene family and functional validation of SmATL59 in cold stress response in...

Arabidopsis Tóxicos en Levadura (ATL) proteins are members of the RING-H2-type E3 ubiquitin ligase subfamily and play important roles in plant physiological processes and stress responses. However, their roles in eggplant (Solanum melongena) remain largely unexplored. In this study, 145 putative SmATL family members were identified and systematically analyzed. Phylogenetic analysis classified them into eight subgroups, and chromosomal mapping revealed their uneven distribution across the eggplant genome. Collinearity analysis identified 37 pairs of collinear genes, while gene structure and motif analyses revealed structural diversity and conserved protein motifs among SmATL members. Under cold stress, transcriptomic analysis showed that several SmATL genes were upregulated, with SmATL59 showing a strong response. qRT-PCR confirmed the gradual induction of SmATL59 during cold treatment. Subcellular localization showed that SmATL59-GFP was mainly localized to the plasma membrane. Overexpression of SmATL59 in Nicotiana benthamiana enhanced cold tolerance, reduced ROS accumulation, increased antioxidant enzyme activities, and upregulated cold-responsive genes. Yeast two-hybrid and luciferase complementation imaging assays demonstrated that SmATL59 interacts with SmATG5a. These results highlight the potential role of SmATL59 in improving cold stress tolerance.

The online version contains supplementary material available at 10.1007/s12298-026-01769-5.