Proteomic insights into nano-chitosan-induced salinity tolerance in solid matrix-primed mung bean seedlings

Mung bean (Vigna radiata (L.) R. Wilczek) is a nutritionally important short-duration legume widely cultivated across the globe. Its productivity is becoming limited in many biogeographic zones due to soil salinity. In the present study, a novel solid matrix priming (SMP) strategy using chitosan and nano-chitosan was evaluated to enhance salinity tolerance in mung beans. SMP-mediated nano-chitosan priming significantly improved germination kinetics, seedling vigour, and growth performance under moderate and high salinity by enabling controlled hydration and minimising imbibitional injury compared to hydro-priming. Biochemical profiling using Native PAGE revealed enhanced activities of α-amylase and other antioxidant isozymes, while SDS-PAGE coupled with Orbitrap high-resolution LC-MS identified differentially expressed proteins uniquely associated with nano-chitosan treatment. Targeted HR-LCMS analysis demonstrated salinity-responsive modulation of major secondary metabolites, including phenols and isoflavones, known for their antioxidant and stress-protective roles. Integrative STRING and Cytoscape analyses further indicated coordinated interactions between these metabolites and salt stress-responsive genes, reflecting comprehensive metabolic reprogramming for adaptation under salinity stress and thereby maintaining productivity. The present findings indicate nano-chitosan-based SMP as a cost-effective, biodegradable, and environmentally sustainable strategy for improving early-stage salt tolerance and metabolic resilience in mung bean.