Integrated In Silico and In Vitro identification of quercetin as an inhibitor against banana bunchy top virus.

Banana bunchy top virus (BBTV) is one of the most destructive viral pathogens of banana, causing substantial yield and production losses worldwide. This study employed an integrated in silico-in vitro approach to identify and experimentally evaluate a potential antiviral compound against BBTV. The three-dimensional structure of the BBTV coat protein (CP) was predicted using I-TASSER, followed by structural refinement and validation. A library of 64 reported antiviral compounds was screened against the CP using AutoDock Vina, and the selected ligand was further characterized using density functional theory (DFT) and triplicate 100-ns molecular dynamics (MD) simulations using GROMACS. The computational predictions were subsequently validated using BBTV-infected banana cv. Grand Naine meristem explants treated with 5-30 mg L⁻¹ quercetin, followed by assessment of explant regeneration and BBTV elimination. Quercetin exhibited a binding affinity of -7.0 kcal mol⁻¹ with favourable hydrogen-bonding and hydrophobic interactions. DFT supported its favourable electronic characteristics, while triplicate 100-ns MD simulations supported CP-quercetin complex stability, with a low RMSD of 1.018 nm, predominantly low RMSF values (<0.30 nm), up to six hydrogen bonds, and limited Rg (1.74 nm) and SASA (116.13 nm²) variation. Subsequently, in vitro testing showed a concentration-dependent response, with the best at 15 mg L⁻¹ quercetin, 80% regeneration and 75% BBTV elimination. Higher concentrations caused phytotoxic responses in banana cultures. Overall, this study provides an integrated computational-experimental framework for evaluating quercetin as a BBTV CP-targeting antiviral candidate and demonstrates its potential application in the production of BBTV-free banana germplasm.