In-silico investigation of potential viral synergism between proteins of Cassava mosaic virus and Cassava brown streak virus

Abstract

Viral synergism in plants has been characterized by the intensification of infection caused by coinfecting viruses, which has a significant negative impact on plant health and crop productivity by exacerbating the disease symptoms. The goal of the study was to determine the protein-protein interactions between two economically significant viruses that co-infect cassava plants, Cassava brown streak virus (CBSV, an Ipomovirus) and Cassava mosaic virus (CMV, a begomovirus). An in-silico approach has been used to elucidate the nature of the co-infection between these two viruses. The methodology focuses on predicting the protein structures using trRosetta, which are then validated by Errat and Ramachandran plots. The proteins from both viruses are docked using ClusPro, and the interacting residues of the docked complexes are highlighted via PDBsum. To further confirm the stability of these complexes, we have conducted 50 ns molecular dynamic simulations on the complexes that displayed the strongest affinity. A well refined protein models are obtained from trRosetta, with the majority scoring above 85% in the ERRAT assessment, and over 90% of the amino acid residues fall within the allowed region of the Ramachandran plot, indicating their favorable conformations. The docking results indicate that the V2 and MP proteins, out of all the CMV proteins, are crucial to the infection process and interact strongly with all CBSV proteins. Our findings reveal synergistic interactions between CMV and CBSV at the protein level. This information could be helpful in developing effective disease management strategies aimed at controlling cassava disease and developing durable resistance against these economically important viruses.