Reexamination ofFusarium graminearum NRRL-13820and NRRL-13852 reported as type A trichothecene producers

Abstract

NRRL-13820 and NRRL-13852 are reported to be two atypicalFusarium graminearum strains type A trichothecene producers [T-2 toxin (T-2) and diacetoxy-scirpenol (DAS)]. These two strains were reexamined by morphological, genetical (DNA / DNA relatedness) and toxicological techniques and compared with 28 wildF graminearum isolates obtained from corn in Italy and the USA. The isolate NRRL-13820 was morphologically confirmed as a typical isolate ofF graminearum, while the isolate NRRL-13852 showed some peculiar characteristics. Nuclear DNA comparison between NRRL-13820 and NRRL-13852 displayed 49% similarity and showed 94 % and 44 % relatedness, respectively, when compared withF graminearum NRRL-13833, which is a well assessed type B trichothecene producer [deoxynivalenol (DON) and 15-acetyldeoxynivalenol]. NRRL-13820, NRRL-13852, and NRRL-13833, as well as the 28 wild isolates, were not able to synthesize T-2, HT-2 nor DAS. Finally, NRRL-13820 and NRRL-13833, but not NRRL-13852, were able to produce DON (120 and 40/μg/g, respectively). The data support the concept that the production of examined type A trichothecenes is very rare inF graminearum.