Tomato bushy stunt virus is a tombusvirus first reported in tomatoes in 1935. Depending upon the host, TBSV causes stunting of growth, leaf mottling, and deformed or absent fruit. The virus is transmitted manually through the use of contaminated cutting tools. A wide variety of species are affected.
The genome of TBSV is a single-stranded postive-sense RNA of ~4800 nucleotides. The virus encodes 5 genes, to express a replicase composed of two proteins (P33 and P92), a capsid protein (CP) of 42 kilodaltons, as well as P19 and P22. The P22 protein is primarily associated with cell to cell movement. The P19 protein is a pathogenicity factor and also is a suppressor of gene silencing.