Nitric Oxide and Photosynthesis Interplay in Plant Interactions with Pathogens

Abstract

Nitric oxide and reactive nitrogen species are key signalling molecules with pleiotropic effects in plants. They are crucial elements of the redox regulation of plant stress responses to abiotic and biotic stresses. Nitric oxide is known to enhance photosynthetic efficiency under abiotic stress, and reactive nitrogen species-mediated alterations in photosynthetic metabolism have been shown to confer resistance to abiotic stresses. However, knowledge about the role of reactive nitrogen species in plant immune responses remains limited. In this review, we highlight recent advancements in understanding the role of NO in regulating stomatal movement, which contributes to resistance against pathogens. We will examine the involvement of NO in the regulation of photosynthesis, which provides energy, reducing equivalents and carbon skeletons for defence, as well as the significance of protein S-nitrosylation in relation to immune responses. The role of NO synthesis induced in pathogenic organisms during plant–pathogen interactions, along with S-nitrosylation of pathogen effectors to counteract their pathogenesis-promoting activity, is also reported. We will discuss the progress in understanding the interactions between reactive nitrogen species and photosynthetic metabolism, focusing on enhancing crop plants’ productivity and resistance in challenging environmental conditions.