US Patent 7691630 Compositions for protecting plants from pathogens

This invention provides novel methods for improving plant quality and yield in the presence of pathogens. The method increases the levels of pathogenesis-related proteins, such as PR1, phenylalanine ammonia lyase, or plant cell wall proteins such as hydroxyproline-rich glycoproteins, in a plant by contacting the plant with a plant systemic inducer and a reactive oxygen species wherein the amount of the reactive oxygen species is sufficient to increase the amount of the pathogenesis-related protein above the level induced by the plant systemic inducer in the absence of the reactive oxygen species. A preferred reactive oxygen species is peracetic acid; a preferred plant systemic inducer is salicylic acid.