Perithecium Production in Fusarium Graminearum Populations and Lack of Correlation with Zearalenone Production

ABSTRACT

Fusarium graminearum is composed of two populations. Group 1 is soilborne, causes crown rot of cereals and grasses and rarely produces perithecia. Group 2 is airborne, causes above-ground diseases and readily forms perithecia of Gibberella zeae. Fusarium graminearum cultures collected from corn and wheat were tested for production of perithecia and for zearalenone, a phytoestrogenic metabolite reported to affect perithecial formation. Nine of 93 cultures tested did not form perithecia on carnation leaf agar (CLA) (= Group 1), while 84 did (= Group 2). When these isolates were grown on a solid rice medium and analyzed for zearalenone, all nine of the Group 1 cultures produced zearalenone, and averaged 1007 μg/g (range: 380–3807 μg/g). Of the 84 Group 2 cultures, 81 produced zearalenone and averaged 1151 μg/g (range < 1–37,996 μg/g); three cultures did not produce zearalenone. When selected isolates of F. graminearum Group 1 and Group 2 were grown on four kinds of agar media, presence, absence, or amount of zearalenone were not related to perithecium production. Thus, no correlation was established between perithecium formation and zearalenone production on rice culture or agar media.

Key Words:

• Fusarium graminearum
• Gibberella zeae
• teleomorph
• zearalenone