Characterization of the OsEXO70 gene family and their response to salt stress in rice.

EXO70 is a key subunit of the exocyst tethering complex involved in vesicle trafficking and plays important roles in plant growth, development, and stress responses. however, Systematic bioinformatic and transcriptional analyses of the EXO70 gene family in rice under salt stress remain unreported. Here, 38 OsEXO70 genes were identified and classified into nine subfamilies (A–I). These genes are unevenly distributed across chromosomes, with 10 segmental duplication events identified. Structural analyses revealed subfamily-specific features, including OsEXO70C1, OsEXO70H1, OsEXO70H3, and OsEXO70I14 were identified as single‑exon genes lacking UTRs. Promoter regions were enriched in hormone‑ and stress‑responsive cis‑elements. Expression profiling showed tissue-specific patterns, with OsEXO70G2 highly expressed in floral organs and most OsEXO70I members exhibiting low basal expression. Under salt stress, subfamilies OsEXO70A, B, C, and E were generally downregulated, whereas OsEXO70D, G, H, and I were upregulated, with OsEXO70I3 and OsEXO70I12 being most strongly induced. This study provides a comprehensive characterization of the OsEXO70 family and a foundation for further functional studies on their roles in salt stress adaptation.