Transcriptomic of salt stress and hydrogen exposure in wild peach seed
Salt stress is a widespread abiotic stressor in plants, affecting gene transcription, metabolite profiles, and overall phenotype. However, the molecular mechanisms underlying plant responses to salt stress, particularly in fruit trees following hydrogen exposure, remain largely unknown. Here, integrated physiological, transcriptomic, and metabolomic strategies were employed to investigate the effects of salt stress and subsequent hydrogen exposure on peach seed (Prunus davidiana) in pot experiments. Seed samples from CK3d, Na3d, and H3d treatments were analyzed for transcriptomic and metabolomic alterations. Salt stress significantly suppressed expression of the rate-limiting PAL and C4H genes involved in flavonoid and alkaloid biosynthesis, leading to reduced levels of epigallocatechin, naringenin, isoscutellarein, and harringtonine. In contrast, hydrogen treatment upregulated PAL and C4H, restoring these metabolite levels. Salt stress also reduced chlorogenic acid accumulation by repressing HCT transcription, whereas hydrogen exposure induced HCT expression and metabolite recovery. Furthermore, salt stress decreased the abundance of steroids, alkaloids, ketone compounds, benzene derivatives, saccharides, and organic acids, while hydrogen treatment restored them to CK levels. This study provides new insights into the molecular and metabolic mechanisms underlying salt stress and hydrogen-mediated responses, deepening understanding of how hydrogen exposure alleviates salt-induced damage in peach seeds. The identified metabolites and key rate-limiting genes offer potential targets for improving peach seed adaptation to salinity stress. Overall, while salt treatment suppressed many metabolites, hydrogen exposure restored their accumulation, suggesting that hydrogen may serve as a promising approach to mitigate salt stress in peach seeds.