Submitted to: Fungal Genetics Newsletter
Publication Type: Abstract Only
Publication Acceptance Date: March 18, 2003
Publication Date: March 18, 2003
Citation: Gale, L.R., Ward, T.J., Balas, V., Kistler, H.C. 2003. Population subdivision in Fusarium graminearum lineage 7 in the United States is correlated with toxin chemotype [abstract]. Fungal Genetics Newsletter. 50:145. Technical Abstract: Isolates of Fusarium graminearum, causing head blight of wheat, from nine U.S. states, representing 86 fields in 53 counties, were characterized using ten single-copy RFLP probes, a telomeric probe and RFLP probes diagnostic for species and lineage. In addition, isolates were assigned to one of three profiles of trichothecene metabolites (chemotypes) using a PCR-based approach. Most of the 712 isolates examined were confirmed as lineage 7, though four isolates from ND had slightly different RFLP patterns and were excluded from further analysis. The telomeric probe was used for clone determination, leaving 587 isolates for subsequent data analyses. Most lineage 7 isolates (94.6%) from the U.S. were of 15acetyl deoxynivalenol (15ADON) chemotype. The 3acetyl deoxynivalenol (3ADON) chemotype was found at 5% and was only identified in samples from ND and MN. The nivalenol chemotype was infrequent at 0.4%. Gene flow analysis demonstrates that the 15ADON population in the U.S. is genetically isolated from the 3ADON population (Nm = 0.5). In comparison, a representative collection consisting of 19 isolates of lineage 7 from Italy was genetically similar to the 3ADON population from the U.S. (Nm > 2). Regarding diversity, no major differences could be discerned between the 3ADON and 15ADON populations from the U.S., even though the 3ADON population was nearly fixed at some RFLP.