Effect of disruption of the enniatin synthetase gene on the virulence of Fusarium avenaceum

Production of the phytotoxic compound enniatin has been proposed to play a role during the infection process of plants by enniatin-synthesizing Fusarium species, Enniatins are cyclohexadepsipeptides synthesized by the multifunctional enzyme enniatin synthetase, To test the hypothesis that enniatin contributes to pathogenicity, enniatin-nonproducing mutants were constructed by gene disruption of the enniatin synthetase gene of a virulent Fusarium avenaceum strain, Four independent enniatin-nonproducing mutants were characterized that did not express enniatin synthetase, as proved by RNA and protein blot analysis, The virulence on potato tuber tissue of the enniatin-nonproducing strains was significantly reduced compared with the virulence of the parent strain and three enniatin-producing transformants, Therefore, we conclude that enniatin production contributes to the virulence of Fusarium avenaceum.