Ethylene signaling and metabolite reprogramming in salt tolerance of Triticum aestivum

Ethylene functions as an important regulator of plant growth and adaptive responses to environmental stresses. Its biosynthesis and signaling pathway have been well-characterized in higher plants however, their integrative regulation, crosstalk with central metabolism, and genotype-specific expression dynamics remain poorly understood in wheat. In this study, ethylene-associated pathway genes were identified and characterized in wheat through phylogeny, transmembrane helices, interaction networks and 3D modeling. Three wheat varieties were evaluated under varying salt levels for morphological, phytochemical, metabolic, and gene expression responses, providing an integrated view of structural, biochemical, metabolite, and molecular adjustments. A total of 21 ethylene biosynthesis and 35 signaling pathway genes were identified in Triticum. aestivum . Phylogenetic studies showed TaSAMS genes were highly conserved, TaACO genes classified based on RXS motif, and ethylene receptors divided into subfamily I and II based on the receiver domain, reflecting evolutionary diversification of ethylene-related components. Experimental validation under salt stress showed reduced biomass, and chlorophyll, while increased phenolics, tannins, and flavonoids, consistent with enhanced accumulation of non-enzymatic antioxidant compounds. Bakhar Star maintained better traits and higher phenolics/tannins, suggesting comparatively higher tolerance to salt tolerance. Metabolite profiling showed enrichment of phenolics, organic acids, sugar alcohols, and stress-related polysaccharides, with organic acids and S-adenosyl methionine linking central metabolism to ethylene biosynthesis. Transcriptional analysis revealed upregulation of TaSAMS3-6B , TaACO2/7 , and TaETR3-6 A in roots while downregulation of receptor in Bakhar Star suggesting altered ethylene sensitivity under salt stress. This integrative study provides potential genetic and metabolic markers that may contribute to future strategies to improve wheat resilience under salinity.