An insight into molecular interaction of PGIP with PG for banana cultivar

PolyGalacturonase Inhibiting Proteins (PGIPs) are leucine rich repeat pathogenesis-related (PR) cell wall proteins, which interact and inhibit the PolyGalacturonase (PG), an enzyme secreted by the pathogen to degrade pectin. Interaction of PGIP with PG limits the vulnerability of PG by the activation of host defense response against pathogenic attack. Erwinia is gram-negative soft rot bacteria responsible for rhizome rot disease in banana and many other crop plants. The interaction of PG with PGIP is one of the crucial steps for plant-pathogen interaction. To study the molecular mechanism of PR proteins, we employed molecular modelling, protein-protein docking and molecular dynamics simulations of banana PGIP (bPGIP) with Erwinia carotovora PG (ecPG). Further, insilico site-directed mutagenesis was performed in Phaseolus vulgaris PGIP (pvPGIP2) to elucidate the interaction with ecPG. Docking and simulation studies divulge that binding of bPGIP and PvPGIP2 with active site residues of EcPG induces structural changes and thereby inhibit the enzyme. This study provides a unique insight into PG-PGIP interaction, which may help in the development of bacterial soft-rot resistant banana cultivars.