Trade-offs for viruses in overcoming innate immunities in plants

Plants recognize viral infection via an immune receptor: nucleotide-binding site (NB)-leucine-rich repeat(LRR)proteins.Another immune receptor, receptor-like kinase/proteins, which share an LRR domain with NB-LRRs, perceive conserved molecules of pathogens called pathogen-or microbe-associated molecular patterns, but NB-LRRs generally perceive particular viral proteins. As viruses can evolve more rapidly than the host immune system, how do plant immune systems, which rely on the perception of proteins, remain effective? Viral adaptive evolution may be controlled by penalties that result from mutations in viral proteins that are perceived by NB-LRRs. Our recent studies in pea(Pisums ativum)suggest a penalty of increased susceptibility to another immune system: when a viral protein mutates to evade one immune system, the virus with the mutated protein becomes more susceptible to another. Such antagonistic pleiotropy of a viral protein by two independent plant immune systems may have precedents. Plants may rely on pairs of immune systems to constrain adaptive evolution by viruses and thereby maintain durable antiviral immunity.INFORMATION FOR AUTHORS:Beginning in 2002, authors may purchase PDFs of their journal articles at prices based on the length of the article. These PDFs may be posted in open areas on their university or company websites.http://apsjournals.apsnet.org/userimages/ContentEditor/1174581064508/Intellectual_Property.pd