Linking ploidy level with salinity tolerance: NADPH-dependent 'ROS-Ca²⁺ hub' in the spotlight

Polyploidy is considered to be a driving force in plant evolution that enabled adaptation to adverse environmental conditions such as soil salinity. This phenomenon is examined by Liu et al. (2019) in relation to root-zone-specific ion transport, and can be explained by more efficient operation of an NADPH-dependent 'ROS-Ca²⁺ hub' and desensitization of ROS-inducible cation channels in polyploid lines. Two hypotheses include that non-selective cation channels in polyploid lines are formed of chimeric tetramers, with some subunits having modified thiol groups (hence, reduced sensitivity to H₂O₂), or alternatively that inactivation of Ca²⁺ channels and higher Ca²⁺- ATPase pump activity may reduce the level of cytosolic free Ca²⁺ and provide a negative control over NADPH oxidase operation.