Portal de Periódicos da CAPES

Identification and Regulation of fusA , the Polyketide Synthase Gene Responsible for Fusarin Production in Fusarium fujikuroi

2012; American Society for Microbiology; Volume: 78; Issue: 20 Linguagem: Inglês

10.1128/aem.01552-12

1098-5336

Violeta Díaz‐Sánchez, Javier Ávalos, M. Carmen Limón,

Microbial Natural Products and Biosynthesis

ABSTRACT Fusarins are a class of mycotoxins of the polyketide family produced by different Fusarium species, including the gibberellin-producing fungus Fusarium fujikuroi . Based on sequence comparisons between polyketide synthase (PKS) enzymes for fusarin production in other Fusarium strains, we have identified the F. fujikuroi orthologue, called fusA . The participation of fusA in fusarin biosynthesis was demonstrated by targeted mutagenesis. Fusarin production is transiently stimulated by nitrogen availability in this fungus, a regulation paralleled by the fusA mRNA levels in the cell. Illumination of the cultures results in a reduction of the fusarin content, an effect partially explained by a high sensitivity of these compounds to light. Mutants of the fusA gene exhibit no external phenotypic alterations, including morphology and conidiation, except for a lack of the characteristic yellow and/or orange pigmentation of fusarins. Moreover, the fusA mutants are less efficient than the wild type at degrading cellophane on agar cultures, a trait associated with pathogenesis functions in Fusarium oxysporum . The fusA mutants, however, are not affected in their capacities to grow on plant tissues.