Transcriptomics uncovers molecular mechanisms underlying salt-inhibited root growth in Festuca rubra

Salt stress markedly inhibits root growth in Festuca rubra , while shoot development remains largely unaffected. Transcriptomic analysis identified 68,062 differentially expressed genes (DEGs) under salt stress. Upregulated genes were found significantly enriched in pathways related to methionine, melatonin, and suberin biosynthesis-processes likely contributing to stress adaptation through root growth suppression and maintenance of ion homeostasis. In contrast, genes associated with gibberellin biosynthesis, abscisic acid (ABA) response, and sugar signaling were downregulated, indicating complex hormonal and metabolic reprogramming. Notably, paradoxical regulation of gibberellin and ethylene signaling pathways suggests the presence of finely tuned mechanisms that balance growth and stress responses. These findings shed light on the molecular basis of root-specific salt stress responses in F. rubra and enhance our understanding of its adaptive strategies under saline conditions.