The basic-region/leucine-zipper-motif 53 improves cotton’s salt tolerance by inhibiting tryptophan-arginine-lysine-tyrosine 68 expression and enhancing superoxide dismutase activity

Basic-region/leucine-zipper-motif (bZIP) transcription factors are key players in modulating plant response to saline stress. However, whether and how GhbZIP53 regulates salt tolerance in cotton (Gossypium hirsutum) is an enigma. Here, GhbZIP53 expression was demonstrated to be activated by NaCl, and GhbZIP53 positively regulated salt resistance by enhancing superoxide dismutase (SOD) activity. GhbZIP53 could directly interact with the promoter of the transcription factor gene tryptophan-arginine-lysine-tyrosine 68 (GhWRKY68), thereby inhibiting its expression. Additionally, GhWRKY68 notably suppressed the transcription of the Cu/Zn-SOD gene GhCSD6 and the Fe-SOD genes GhFSD2 and GhFSD3, further reducing SOD activity under salinity stress. Silencing each of GhCSD6, GhFSD2, and GhFSD3 also markedly enhanced cotton's sensitivity to saline stress. These results suggest that the GhbZIP53-GhWRKY68-GhSODs module serves crucial roles in salt tolerance by elevating SOD activity in cotton plants.