Microbial fungicides—the natural choice

Abstract

Abstract Fungicidally active secondary metabolites have been found throughout the microbial system, with major new discoveries especially from Actinomycetes and Basidiomycetes. New and interesting modes of action have been revealed (e.g. the unique way in which strobilurin inhibits mitochondrial respiration, or trehalase inhibition by validamycin). These new compounds have been used either directly as microbially produced fungicides (e.g. kasugamycin against rice blast) or as lead molecules for chemical synthesis of novel chemistry (e.g. pyrrolnitrin used as a fungicidal seed dressing). However, a real breakthrough, resulting in a major new group of fungicides based on naturally occurring metabolites is yet to come. Three new fungicidal fungal metabolites are described and one is highlighted in detail in order to illustrate the entire process from isolation of antagonistic microorganisms to structure elucidation of the active molecule.