Abstract
Plant defense against the fungal pathogen Sclerotinia sclerotiorum depends on jasmonate, ethylene, and salicylic acid signaling. To further explore host responses to invasion by this ascomycete, wild-type and coi1 mutant plants were subjected to ATH1 microarray and comprehensive hormone analyses. Besides induction of several stress hormones, this host-pathogen interaction was shown to alter growth hormone levels. Most jasmonate and ethylene biosynthetic and signaling genes were induced by S. sclerotiorum, but several of them were regulated independently of coi1. OPDA, phytoprostanes, and auxin likely contribute to this coi1-independent regulation of gene expression. Phenotypic tests have provided evidence for protection against S. sclerotiorum by the innate immune system and by secondary metabolites. Further analyses of pathogen recognition, defense signaling and deployment are under way.
