Certain embodiments of the invention relate to mutant forms of flock house virus B2 protein characterized by having enhanced suppressor of RNA silencing activity as compared to wild type flock house virus B2 protein. Certain embodiments of the invention relate to nucleic acid sequences and vectors that encode and/or direct expression of such mutant forms of flock house virus B2 protein in eukaryotic cells. Certain embodiments of the invention relate to methods of using such mutant forms of flock house virus B2 protein and/or nucleic acid sequences and vectors that encode and/or direct expression thereof in eukaryotic cells to increase a replication rate of a plant or animal virus in a plant or animal cell.