Salt stress severely constrains wheat growth and yield by inducing osmotic imbalance, ion toxicity, and excessive accumulation of reactive oxygen species (ROS). Although salt-tolerant cultivars can adapt through rapid signaling transduction and maintenance of cellular homeostasis, the underlying dynamic regulatory networks remain insufficiently characterized. In this study, we reanalyzed publicly available time-series RNA-seq data (0, 1, 3, 6, 12, and 24 h) from the salt-tolerant wheat cultivar Xiaoyan22 under salt stress and constructed a time-series-based co-expression network using weighted gene co-expression network analysis (WGCNA). Multiple gene modules were identified, among which the black module showed significant positive correlations with both salt treatment (treatment_bin) and stress duration (time_h). This module displayed a progressively increasing eigengene expression pattern throughout the stress period. Gene significance (GS) was positively correlated with module membership (MM), facilitating the identification of highly connected hub genes within this module. Functional enrichment analysis indicated that genes in the black module were primarily associated with DNA replication and genome stability maintenance, RNA metabolic regulation, phenylpropanoid metabolism, and cuticle/suberin/wax biosynthesis. Physiological analysis further revealed enhanced activities of superoxide (SOD), peroxide (POD), and catalase (CAT), enhanced accumulation of proline and soluble sugars, and a time-dependent increase in MDA under salt stress. qRT-PCR confirmed significant induction of candidate genes, including a ZAR1-like receptor kinase, Remorin, and NETWORKED 1D. Collectively, these findings integrate co-expression network inference with physiological and molecular validation, providing candidate regulators and pathways for understanding salt tolerance and supporting future molecular breeding efforts.

Rice grain yield and drought tolerance are critical for global food security. So far, only a few genes have been reported to regulate both traits simultaneously. Here, we characterize OsFLO1, a previously unreported FAD-linked oxidoreductase, as a dual regulator of grain development and drought stress tolerance in rice. Genome-wide association studies (GWAS) revealed natural variation in OsFLO1, with haplotypes showing geographic adaptation to local rainfall. Functional analysis demonstrated that overexpression (OX) lines exhibited larger grains and improved panicle traits, while knockout (CR) lines showed reduced grain size and yield components despite increased tiller number. Regarding drought tolerance, OX lines of OsFLO1 enhanced drought tolerance, as evidenced by increased root length and antioxidant activities, whereas knockout (CR) lines displayed impaired stress responses. We further show that OsWRKY53 directly binds the OsFLO1 promoter, thereby activating its expression and coordinating both grain development and stress responses. Together, these results suggest that OsFLO1 functions as a key regulator coordinating grain development and drought tolerance, making it a promising target for improving rice productivity.