The NAC (NAM, ATAF1/2, and CUC1/2) family of transcription factors (TFs) play critical roles in regulating salt tolerance across diverse plant species. This study identified and characterized 101 NAC TFs in eggplant (Solanum melongena L.), revealing their diverse physicochemical properties, chromosomal distributions, and evolutionary relationships. Based on its salt stress-induced expression pattern and homology to known salt-responsive NAC factors, SmNAC28 was selected as a key candidate for functional investigation of salt tolerance. Expression profiling indicated that SmNAC28 is preferentially expressed in roots and stems, and its transcript levels are modulated by salt stress. Subcellular localization confirmed that SmNAC28 localizes to both the plasma membrane and nucleus, a dynamic distribution regulated by S-palmitoylation. Under normal conditions, SmNAC28 is anchored to the plasma membrane and nucleus via S-palmitoylation; upon salt stress exposure, it undergoes depalmitoylation and translocates to the nucleus. Using a hairy root transformation system in eggplant, we demonstrated that overexpression of SmNAC28 in roots significantly enhanced salt tolerance by mitigating oxidative damage, maintaining ion homeostasis, and promoting osmotic adjustment. Analysis of transcript levels further revealed that SmNAC28 overexpression upregulated ion transporter genes (NHX2, CHXs), signaling genes (CIPKs), and the proline biosynthesis gene (P5CS), which demonstrated that SmNAC28 integrates antioxidant defense, ion homeostasis, and osmotic regulation to confer salt tolerance. This study reveals the response mechanism of SmNAC28 to salt stress of the eggplant transcription factor SmNAC28 under salt stress, and provided a research foundation for salt tolerance breeding.
Fan et al. (Tue,) studied this question.