Multi-Omics Analysis of Drought and Growth Responses in Nitraria sibirica: Insights from Habitat-Specific and Developmental Comparisons

Global climate change-driven drought aggravation seriously threatens the survival and distribution of desert shrubs. Nitraria sibirica Pall. has outstanding drought tolerance, yet its growth adaptation strategies and internal regulatory mechanisms under different soil moisture conditions lack systematic research. This study combined physiological determination with transcriptome and metabolome analyses to investigate its physiological responses and molecular regulation mechanisms at different growth stages and habitats. Nitraria sibirica from riparian habitats exhibited lower leaf organic carbon and higher total nitrogen. Desert-grown N. sibirica possessed far more drought-responsive differentially expressed genes and metabolites than riparian ones. Hormone signal transduction and lipid metabolism dominated regulation in riparian habitats, whereas secondary metabolite biosynthesis and amino acid metabolism—especially flavonoid biosynthesis and tryptophan metabolism—were core in desert habitats. Its drought response displayed distinct stage-specificity, with hormone signal transduction most enriched in drought-responsive genes across growth periods. This study clarifies the stress adaptation mechanisms of desert shrubs and provides theoretical support for germplasm evaluation and vegetation restoration in arid regions.