Physiological and multi-omics profiling uncovers the sulfur tolerance mechanism in Tamarix ramosissima

Tamarix ramosissima , a xerophytic shrub with significant ecological-economic value, exhibits marked soil sulfur (S) accumulation capacity, yet its shoot transcriptional-metabolic responses to varying S levels remain uncharacterized. This study integrates physiological, transcriptomic, and metabolomic analyses to investigate S-mediated adaptation mechanisms in T. ramosissima cuttings. High S exposure significantly inhibited growth and induced oxidative stress, evidenced by reduced activities of antioxidant enzymes (SOD, CAT, APX), increased malondialdehyde (MDA) and glutathione (GSH, GSSG) levels, and decreased ascorbic acid (AsA, DHA) content. Transcriptome analysis identified key S-responsive pathways, including secondary metabolism and signal transduction, with differential expression of genes encoding POD, GR, GST, and photosystem proteins. Metabolome profiling quantified 489 differentially accumulated metabolites, primarily flavonoids, phenolic acids, and alkaloids. Crucially, integrative multi-omics analysis revealed that phenylpropanoid biosynthesis and plant hormone signal transduction were the core pathways significantly enriched at both the transcript and metabolite levels. This study elucidates the complex molecular networks underlying sulfur tolerance and accumulation in T. ramosissima , deepening our understanding of plant adaptation in S-rich desert ecosystems. • Excess Sulfur inhibits Tamarix ramosissima growth and induces antioxidant adaptation. • Tamarix ramosissima had strong sulfur accumulation, transport and tolerance. • Phenylpropanoid biosynthesis and hormone signaling are primary sulfur-responsive pathways. • A model of the mechanisms of sulfur response in Tamarix ramosissima is proposed.