A secreted lipase ofFusarium graminearumis a virulence factor required for infection of cereals.

Fusarium graminearumis the causal agent of the Fusarium head blight (FHB) and a destructive pathogen of cereals accounting for high grain yield losses especially on wheat and maize. Like other fungal pathogens,F. graminearumsecretes various extracellular enzymes, which are hypothesized to be involved in host infection. Extracellular lipolytic activity ofF. graminearumwas strongly induced in culture by wheat germ oil; this allowed us to isolate, clone, and characterize a gene (FGL1) encoding a secreted lipase. Expression analysis indicated thatFGL1is induced by lipid-containing substrates and repressed by glucose.In planta,FGL1transcription was detected 1 day post-infection of wheat spikes. The function of theFGL1gene product was verified by specifically demonstrating lipase activity after expression in a heterologous host. Ebelactone B, a known lipase inhibitor, repressed the lipolytic activity of the enzyme. Disease severity was strongly reduced when wild-type conidia were supplemented with ebelactone B. Transformation-mediated disruption ofFGL1led to reduced extracellular lipolytic activity in culture and to reduced virulence to both wheat and maize. [ABSTRACT FROM AUTHOR]