Screening and characterization of a chemical regulator for plant disease resistance.

ABSTRACT

Plants activate systemic acquired resistance (SAR), a form of long-lasting induced defense, to confer protection against a broad spectrum of pathogens. SAR induction is associated with the salicylic acid (SA)-mediated defense signaling networks. For detailed understandings of the SA-mediated signaling of SAR induction, we screened chemical inhibitors that block SA-mediated signaling from a 9600-compound chemical library. As a result, we identified one candidate chemical, 4-phenyl-2-{[3-(tri-fluoromethyl)anilino]methylidene}cyclohexane-1,3-dione (PAMD), that suppresses the expression of pathogenesis-related (PR) gene. PAMD also down-regulates SA-induced gene expression and enhances susceptibility to pathogen.