The loss of RBOHD function modulates root adaptive responses to combined hypoxia and salinity stress in Arabidopsis

•The lack of functionality in RBOHD protein increases plants sensitivity to combined hypoxia and salinity stress.•The above phenomenon is due to poor K+ retention ability and increased rate of Na+ and Cl− uptake in rbohD mutant plants.•Mild hypoxia stress reduces detrimental impact of salinity by regulating RBOHD activity.