Arsenic tolerance unveiled in Arabidopsis: CPK23 and PHT1;1 alliance

Arsenate As(V), characterized as a metalloid with heavy metal properties, is prevalent in various environments. The consumption of food derived from plants contaminated with arsenate contributes significantly to human exposure to arsenic, posing potential health risks. However, the mechanisms governing plant responses to arsenate stress and the regulation of relevant transporter functions remain inadequately understood. Recently, Wang and co-workers, identified a calcium-dependent protein kinase, specifically CALCIUM-DEPENDENT PROTEIN KINASE 23 (CPK23), which shows interaction with the plasma membrane As(V)/Pi transporter PHOSPHATE TRANSPORTER 1;1 (PHT1;1) to channelize the Ca²⁺ signal in Arabidopsis roots under As(V) stress. The authors observed that cpk23 mutants showed increased sensitivity, whereas the overexpression of CPK23 resulted in enhanced tolerance under As(V) stress conferring role in As stress. Moreover, it has been demonstrated that CPK23 phosphorylates PHT1.1 at the Ser⁵¹⁴ (S⁵¹⁴) site is crucial for its function and proper localization under As(V) stress. Thus, this commentary offers valuable insights into the induction of a notable Ca²⁺ signal in Arabidopsis roots under As(V) stress that could guide crop bioengineering efforts aimed at addressing arsenate pollution in soil with targeted strategies.