Glutathione and NADPH in plant responses to H2O2

Modifications of cell redox state are integral to plant responses to most kinds of stresses. Intense interest has focused on the roles of oxidative stress in determining immune responses of plants to pathogenic invaders, but the interplay between oxidants such as H2O2 and antioxidants like glutathione and NADPH is still obscure. To elucidate these questions, we have used a model Arabidopsis catalase-deficient line in which increased H2O2 availability activates localized cell death and disease resistance in a salicylic acid-dependent manner. Activation of cell death and resistance by H2O2 is also dependent on glutathione status and is abolished by knocking out specific NADP-linked dehydrogenases. Thus, in addition to its antioxidant function, the NADPH-glutathione redox hub plays key signaling roles in transmitting oxidative stress signals involved in determining plant disease resistance responses.