Nitrogen availability and production of bikaverin and gibberellins in Gibberella fujikuroi.

GIORDANO, W., AVALOS, J., CERDA-OLMEDO, E. AND DOMENECH, C. E.

FEMS MICROBIOLOGY LETTERS

Elsevier

Año: 1999 vol. 173 p. 389 - 393

0378-1097

Production of bikaverin and gibberellins by Gibberella fujikuroi started after depletion of the nitrogen source, but not after depletion of phosphate. Despite this similarity, the regulation of both pathways by nitrogen involved two different mechanisms. This conclusion was supported by the fact that the production of bikaverin, in contrast to the gibberellins, was not inhibited by nitrate in a mutant that could not utilize it. The different regulation of both pathways was clearly demonstrated by a mutant that overproduced bikaverin but lacked gibberellins. An optimal bikaverin production required a low pH, with a sharp drop at about pH 5. The syntheses of fungal secondary metabolites, such as bikaverin and gibberellins, are not subject to common regulation, but respond to various combinations of signals, such as nitrogen availability, nitrate and the pH of the medium.