An adaptive evolutionary shift in Fusarium head blight pathogen populations is driving the rapid spread of more toxigenic Fusarium graminearum in North America.
Analysis of Fusarium head blight (FHB) pathogen diversity revealed that 3ADON producing Fusarium graminearum are prevalent in North America and identified significant population structure associated with trichothecene chemotype differences (F(ST)>0.285; P<0.001). In addition, we identified a trichothecene chemotype cline in Canada and documented a recent and significant shift in FHB pathogen composition by demonstrating that the 3ADON chemotype frequency in western Canada increased more than 14-fold between 1998 and 2004. On average, isolates from 3ADON populations produced significantly (P<0.05) more trichothecene and had significantly (P<0.005) higher fecundity and growth rates than isolates from the 15ADON population. These results indicate that selection is driving the rapid spread of an introduced pathogen population that is more toxigenic and potentially more vigorous. The discovery of this previously unrecognized pathogen diversity has significant implications for food safety and cereal production in North America.
Microbial Genomics and Bioprocessing Research Unit, Agricultural Research Service, United States Department of Agriculture, Peoria, IL 61604, USA. todd.ward@ars.usda.gov
Todd J
TJ
Ward
Randall M
RM
Clear
Alejandro P
AP
Rooney
Kerry
K
O'Donnell
Don
D
Gaba
Susan
S
Patrick
David E
DE
Starkey
Jeannie
J
Gilbert
David M
DM
Geiser
Tom W
TW
Nowicki
D000220:Adaptation, Biological; D002170:Canada; D004271:DNA, Fungal / Q000235:genetics; D005670:Fusarium / Q000737:chemistry / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D005838:Genotype; D016533:Mycological Typing Techniques; D009656:North America; D010935:Plant Diseases / Q000382:microbiology*; D016133:Polymerase Chain Reaction / Q000379:methods; D014255:Trichothecenes / Q000096:biosynthesis*; D014774:Virulence
D004271:DNA, Fungal; D014255:Trichothecenes