Biocontrole de Fusarium verticillioides em milho

Abstract

Brazil shows great prominence in the production of grain, maize and widely grown of great economic and nutritional importance. However these cultures are often affected by fungi in the pre-harvest or storage. Among these fungi, Fusarium verticillioides, stands out by deterioration with nutritional loss, and contamination by mycotoxin production in maize and its products. The control of this fungus is extremely important, since the chemical or physical methods with high costs may affect the environment and food due to contamination by waste. Thus, it is suggested as a biocontrol economically viable and less harmful to the environment and the consumer. This work aimed to select antagonists yeasts against to mycotoxigenic F. verticillioides. The analysis of the process of antibiosis with yeasts isolated from the natural microbiota of maize and the ability to express character killer were performed. A total of 34 isolates were obtained and tested, among these 5 isolates showed stable antagonism for more than 30 days againts mycotoxigenic strain F. verticillioides 103F. The five yeasts were identified with commercial kit Rapid Yeast Plus ™ (Remel) as Saccharomyces cerevisiae, isolated AM2 (-1) and AM3 (-4), Hansenula wingei AM2 isolated (-2) and Pro wickerhamii isolate AM5 (-1). The isolate AM12 was not identified with the kit. Yeasts AM5 (-1) and AM12 (-6) were character killer positive (k+) for four of the five yeast sensitive tests in 72 hours. Yeast AM2 (-2) was k+ for three sensitive strains in 120h. The positive character killer was expressed by yeasts at 25 and 37 ° C. These positive killer yeasts have good prospects for application in the biocontrol of fumonisin producer F. verticillioides.