SlGATA17, A tomato GATA protein, interacts with SlHY5 to modulate salinity tolerance and germination

The GATA transcription factor family participates in plant biological processes and abiotic stress across various crop species, but their function in response to salinity stress remains unexplored, particularly in tomato. Here, a tomato (Solanum lycopersicum) GATA gene, SlGATA17, was characterized in the tolerance to salinity stress. SlGATA17 had transcription activity in yeast, and the transcriptional activation domain was location on 32–60 amino acids of the N-terminal. SlGATA17 expression was induced by heat, cold, ABA, ACC and IAA treatments, but inhibited by NaCl and PEG treatments. In this study, the Slgata17 mutant plants showed slight injury symptoms compared to wild-type plants under salinity stress, and higher expression levels of stress-related marker genes (SlDREB2A, SlAREB1, SlRD29A and SlP5CS1). Heterologous expression of SlGATA17 in Arabidopsis promoted seed germination under NaCl, ABA and mannitol conditions, and inhibited ABA content and the expression levels of ABA related genes (AtNCED3, AtNCED5, AtNCED9, AtABI3, AtEM1 and AtEM6). However, SlGATA17 transgenic Arabidopsis were hypersensitive to NaCl at the post-germination stage. Yeast two assay and BiFC assay showed that tomato transcription factor ELONGATED HYPOCOTYL (SlHY5) interacts with SlGATA17. Yeast one assay and Dual-Luc assay showed that SlHY5 negatively regulated SlGATA17 expression via binding to the GATA-box of SlGATA17 promoter. SlHY5-SlGATA17 might function as a regulatory module in response to abiotic stress.