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SESSION 3: PATHOGENESIS – EPIDEMIOLOGY AND POPULATION
GENETICS
P66 - PCR validation and chemotyping of causal
Fusarium species of Fusarium head blight on south
african wheat
N. Baloyi 1 , S. L. Sydenham 1 , C. I. P. De Villiers 1 , M. Gryzenhout 2
1 ARC-Small Grain Institute, Bethlehem, Free State Province, South Africa, Private Bag X29, 9701;
2 Department of Plant Sciences, University of the Free State, Bloemfontein, Free State Province, South
Africa, P.O. Box 339, 9300
E-Mail: sydenhams@arc.agric.za
Species identification and chemotyping of 203 single spore isolates collected from
Fusarium head blight (FHB) symptomatic wheat spikes from four widespread and
representative localities (Dundee, Groblersdal, Frankfort and Vaalharts) were
validated using molecular assays. Single spore isolates were plated on potato
dextrose agar (PDA). DNA was extracted with the modified
cetyltrimethylammonium bromide (CTAB) method (Saghai-Maroof et al. 1984).
Species-specific primers were used for PCR analysis (Obanor et al. 2012). The
presence of mycotoxins, NIV, 3-ADON and 15-ADON, was determined using tri12
and tri13 PCR primers. PCR products were run on 2% agarose gels stained with
GR-green and sizes were determined with a 100bp DNA ladder.
Three Fusarium species were identified: F. graminearum, F. boothii and F.
pseudograminearum. In Frankfort both F. graminearum and F.
pseudograminearum where found. F.graminearum and F.boothii were both found
in Groblesdal. Dundee and Vaalharts only had F.graminearum present. F.
graminearum was the predominant causal species of FHB on wheat in all four
localities. Two trichothecene types, 15-ADON and NIV, were detected among the
isolates, with the 15-ADON type predominating in all the localities. No 3-ADON
producing isolates were found. These results identifying F. graminearum as the
predominant casual species of Fusarium head blight on wheat in South Africa
correlate well with findings published by Boutigny et al. (2011). This information
will help breeders and pathologists safeguard wheat, enabling them to target
useful/appropriate resistance against the specific causal Fusarium species.
Additionally, it will help with the establishment of a Fusarium isolate collection to
be kept at the ARC-SGI for future reference.
Keywords: chemotype, F. graminearum, species-specific primers, trichothecenes
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