Comparative transcriptomic profiles of Haloxylon ammodendron under the salinity stress

Haloxylon ammodendron is a highly salt-tolerant plant vital for desertification control in northwest China. Despite its ecological importance, the molecular mechanisms underlying its exceptional salt tolerance remain largely unexplored. This study aimed to elucidate the temporal dynamics of its transcriptomic responses to varying salinity levels.

Temporal analysis revealed distinct gene expression patterns across low, medium, and high salt concentrations, with unique regulatory trends over time. Differential expression analysis identified 2,630 DEGs at 7 days, 4,533 DEGs at 21 days, and 2,581 DEGs at 30 days, highlighting 21 days as a critical period for salt response. WGCNA on 19,399 genes at day 21 revealed three modules (ME4-yellow, ME6-red, ME9-magenta) significantly associated with salt stress. These modules were enriched in genes involved in photosynthesis, amino acid metabolism, carbohydrate metabolism, and stress response pathways. Hub gene analysis identified ATPD and five sub-key genes as central regulators of the salt response network.

This study provides the first comprehensive temporal transcriptomic analysis of H. ammodendron under varying salinity concentrations, revealing novel molecular insights into its salt adaptation mechanisms. The identified hub genes and pathways offer valuable targets for understanding extreme salt tolerance and enhancing desert reclamation efforts in arid regions.