ZEARALENONE PRODUCTION IN FUSARIUM-GRAMINEARUM VARIANTS AFTER TREATMENT WITH NITROSOGUANIDINE

Zearalenone is a secondary metabolite produced by Fusarium graminearum and apparently involved in the control its sexual reproduction. When ingested by some animals it can induce estrogenic effects. The catalytic reduction of zearalenone produces zearalanol, which has anabolic effects in bulls and sheeps. In a Fusarium graminearum isolate, good producer of zearalenone, the possibility to obtain variants with greater zearalenone production through the action of a mutagenic agent (Nitrosoguanidine) was investigated. Forty samples, differing from the control on morphological aspects, growth rates and pigmentation, were selected. Through zearalenone quantification by HPLC, 10 variants that showed and increase in yields of 2 to 16 times, in comparison to the control, were obtained. The stability for zearalenone production in these variants was tested by 12 sucessive transfers in cultive medium. In the conditions tested, 2 stable variants which maintained zearalenone overproduction were obtained.