Interaction of Plant Epicuticular Waxes and Extracellular Esterases of Curvularia eragrostidis during Infection of Digitaria sanguinalis and Festuca arundinacea by the Fungus

Curvularia eragrostidis, a causal agent of head blight on the weed (Digitaria sanguinalis), did not cause disease on the turfgrass Festuca arundinacea. Different extracellular esterase isoenzymes were detected in saprophytic and parasitic phases during the fungal germination. The epicuticular waxes of D. sanguinalis were more efficient to induce the secretion of esterases from the fungus than that of F. arundinacea, but were more rapidly degraded by the fungal enzymes. Component analysis indicated that the epicuticular waxes from D. sanguinalis were mostly composed of alcohols, with 54.3% being 9,12Octadecadien-1-ol. The main component of F arundinacea waxes was alkyl compounds, with 49.8% being olefin, 9-Tricosence. More long-chained esters were found in D. sanguinalis waxes, which were easier to be digested than those in F. arundinacea waxes by extreacellular esterases of the fungus. Epicuticular waxes play a role in varying pathogenicity of C. eragrostidis on D. sanguinalis and F arundinacea.