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.