In Vitro Interaction between Geminivirus Replicase Protein and the Npr1 Gene Promoter from Chilli Pepper (c

The Geminivrius Replicase (Rep) protein has been suggested as one of the key determinants of the pathogenicity by suppressing the expression of NPR1 gene as one of the key regulators in Systemic Acquired Resistance (SAR) during pathogen invasion. The aim of this study was to investigate the interaction possible between the Rep protein and the NPR1 gene promoter. The experiment was conducted using Electrophoretic Mobility Assay (EMSA) approach between Core and Distal promoter and Rep protein, verified using Western Blot Analysis. This study successfully showed interaction between both molecules through in-silico and in-vitro analysis. The interaction was observed only between the NPR1 gene distal promoter particularly on 2nd Fragment (PD_CbNPR1-F2). In-silico analysis using HDOC software obviously exhibited that the most likely interaction is located at PD_CbNPR1-F2.4 segment indicated by the highest docking score and rsmd ligand (-176.56 and 26.80 Å respectively). Thus, this finding is in line with our above hypothesis regarding binding activity between the Rep protein and the NPR1 gene promoter.