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SESSION 3: PATHOGENESIS – EPIDEMIOLOGY AND POPULATION
GENETICS
P42 - Fusarium graminearum/Gibberellea zeae
perithecia formation on winter wheat straw and maize
stalks in Swedish climate
P. Persson, H. Bötker, A. K. Kolseth
Swedish University of Agricultural Sciences, Crop Production Ecology, PO Box 7043, SE 750 07
Uppsala, Sweden
E-mail: paula.persson@slu.se
High levels of the Fusarium generated mycotoxin deoxynivalenol was a major
problem in cereal grain in Sweden during 2011 and 2012. Fungal analyses of
grains showed that Fusarium graminearum was the main cause of the toxin
contaminations. The spread of F. graminearum is mainly thought to be caused by
macroconidia originating from contaminated plant material of a previously grown
crop. The role of ascospores formed by its sexual stage Gibberella zeae in the
spread in North European climate conditions is poorly studied. To investigate the
importance of ascospore production in Swedish climate we studied perithecia
formation on winter wheat straw and maize stalks together with ascospore
formation. A F. graminearum strain isolated from winter wheat grain, known to
produce perithecia, was multiplied in liquid medium which was used as inoculum.
Winter wheat straw and maize stalks were sterilized and soaked in F.
graminearum inoculum for 5 min and were incubated at room temperature for
seven days. The material was thereafter placed outdoors in Uppsala in late May
and registered every five days until early July for perithecia formation, including
one registration late August. When perithecia started to form, microscope glass
slides with a transparent tape were placed a few centimeters over perithecia, as
spore traps, with regular changes until late August. The slides were kept in room
temperature until microscope readings. (Method according to Manstretta, V. &
Rossi, V., UCSC, Piacenza, Italy)
The results showed that perithecia were formed during the whole test period both
on winter wheat straw and abundantly on maize stalks. Registered ascospores
peaked the second half of July. This indicates that ascospores may play an
important role in the wider spread of Fusarium graminearum in the North
European area. The experiment will be repeated 2013.
Keywords: Gibberella zeae, perithecia, ascospores
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