Link to home

Molecular Phylogenetic Analysis, Trichothecene Chemotype Patterns, and Variation in Aggressiveness of Fusarium Isolates Causing Head Blight in Wheat

July 2012 , Volume 96 , Number  7
Pages  1,016 - 1,025

Ali Malihipour and Jeannie Gilbert, Cereal Research Centre, Agriculture and Agri-Food Canada, Winnipeg, MB R3T 2M9, Canada; Michele Piercey-Normore, Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada; and Sylvie Cloutier, Cereal Research Centre, Agriculture and Agri-Food Canada, Winnipeg, MB R3T 2M9, Canada

Go to article:
Accepted for publication 9 February 2012.

Certain Fusarium species cause Fusarium head blight (FHB) in wheat and other small grains. Differences in characteristics of the pathogen species/isolates used in breeding programs may affect reaction of host genotypes, leading to erroneous results. To clarify differences among Fusarium isolates from different geographical zones, the phylogenetic, chemotypic, and pathogenic abilities of 58 isolates collected from three wheat-producing countries (Canada, Mexico, and Iran) were investigated. Phylogenetic relationships among the isolates were characterized using the Tri101 gene sequence. All Canadian and Iranian isolates clustered in one group and were identified as F. graminearum lineage 7 (=F. graminearum sensu stricto) within the F. graminearum (Fg) clade. The isolates from Mexico were identified as either F. graminearum lineage 3 (=Fusarium boothii) within the Fg clade or Fusarium crookwellense. A polymerase chain reaction assay based on the Tri12 gene identified three trichothecene chemotypes of 15-ADON, 3-ADON, and NIV, with 15-ADON being the most common. All F. boothii isolates from Mexico were of the 15-ADON chemotype, while all F. crookwellense isolates were determined to be NIV producers. While we did not find the NIV chemotype among the Canadian isolates, 25.6% of the Iranian isolates were determined to be NIV producers. High level of variation in aggressiveness was also observed among and within the species tested: F. graminearum sensu stricto isolates were the most aggressive, followed by those of F. boothii, and lastly by F. crookwellense. The differences observed among the isolates may explain why wheat lines/cultivars demonstrate different reactions to FHB in different geographical zones.

This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 2012.