Recombination with host transgenes and effects on virus evolution: An overview and opinion

This commentary relates to the work by M. Borja et al, (M. Borja, T. Rubio, H. B. Scholthof, and A. O. Jackson, MPMI 12:153-162, 1999) that shows that wild-type virus can be restored frequently by double recombination events between a tomato bushy stunt virus mutant with deletions inactivating the c oat protein gene and a coat protein transgene. Here, we focus on evidence s uggesting that new viruses might evolve via recombination with transgenes u sed for disease resistance, and discuss the potential effects of widespread use of these sources of resistance on virus evolution. We argue that the b enefits arising from using transgenic sources of resistance for virus disea se control outweigh potential negative consequences of evolution of novel h ybrid viruses with destructive disease potential.