Chemotyping of Fusarium graminearum from durum wheat in an area of Emilia Romagna

Fusarium graminearum is one of the main causal agents of fusarium head blight (FHB) of wheat. F. graminearum population can be divided into two chemotypes based on the production of the trichothecenes deoxynivalenol (DON) and nivalenol (NIV). DON-producing isolates can be further distinguished on the basis of the predominant acetyl DON derivative that produces 3-acetyl DON (3-AcDON) or 15-acetyl DON (15-AcDON). In this investigation, fungal isolates collected between 2006 and 2007 from symptomatic spikes of durum wheat in several fields, around Bologna (Emilia-Romagna region, northern Italy), were tested with a multiplex version (Starkey et al.,, Fungal Genet. Biol., doi: 10.1016/j.fgb.2007.03.001, 2007) of the chemotype-specific PCR proposed by Ward et al. (Natl. Acad. Sci. USA 99: 9278-9283, 2002). All the three fungal chemotypes were found. In particular, of the 66 isolates tested, 79% belonged to the 15-AcDON chemotype, 15% to the 3-AcDON and 6% to NIV. The 15-AcDON chemotype was the most frequent. This is the first time that a population of F. graminearum, exclusively isolated from durum wheat from the area under investigation, was examined for chemotypes. Taking into consideration the variability of the Italian environmental characteristics, it would be desirable to monitor wheat fields from all over the country, especially where durum wheat prevails, to better understand the distribution of F. graminearum chemotypes in this country.