Nitrile-Specific Protein NSP2 and Its Interacting Protein MPK3 Synergistically Regulate Plant Disease Resistance in Arabidopsis

Abstract

Glucosinolates and their degradation products have a wide range of actions and are important components of plant defense. NSP2 (nitrile-specific protein 2) is a key regulator in the breakdown process of glucosinolates. However, the precise function of NSP2 in plant disease resistance beyond its role in glucosinolate degradation is still unclear. In this study, we discovered that NSP2 which was induced by Pst DC3000, influenced PR genes expression and reactive oxygen burst. Additionally, omics analysis revealed that NSP2 was engaged in plant-pathogen interaction and several hormone signal transduction pathways. Furthermore, immunoprecipitation-tandem mass spectrometry analysis (IP-MS), bimolecular fluorescence complementation (BiFC), and co-immunoprecipitation demonstrated that NSP2 interacts with MPK3. Genetic analysis shows that NSP2 may be a function downstream of MPK3. Upon pathogen inoculation, NSP2 protein levels increase while MPK3 protein levels decrease. Moreover, the level of phosphorylated NSP2 decreases. Taken together, this study sheds light on a new mode of synergistic action between NSP2 and MPK3 in the disease resistance process.