Multifaceted defense and counter-defense in co-evolutionary arms race between plants and viruses

Plants have evolved sophisticated surveillance and defense mechanisms against constant attacks by different types of microbial pathogens including viruses. Nucleotide-based RNA silencing and receptor-based innate immunity constitute the primary plant defense to viral infection. To establish their infections, plant viruses have also evolved virulence strategies to suppress host defenses. This ever-lasting co-evolutionary arms race between the plant hosts and viruses has shaped today's multifaceted defense and counter-defense layout. A better understanding of this process will certainly assist in the development of new plant varieties with enhanced durable resistance and novel approaches to control viral pathogens for sustainable agriculture. In this addendum, we briefly review the current knowledge of the plant immune response to viral infection and discuss defense and counter-defense strategies.