New tricks of an old enemy: isolates of Fusarium graminearum produce a type A trichothecene mycotoxin.
The ubiquitous filamentous fungus Fusarium graminearum causes the important disease Fusarium head blight on various species of cereals, leading to contamination of grains with mycotoxins. In a survey of F. graminearum (sensu stricto) on wheat in North America several novel strains were isolated, which produced none of the known trichothecene mycotoxins despite causing normal disease symptoms. In rice cultures, a new trichothecene mycotoxin (named NX-2) was characterized by liquid chromatography-tandem mass spectrometry. Nuclear magnetic resonance measurements identified NX-2 as 3α-acetoxy-7α,15-dihydroxy-12,13-epoxytrichothec-9-ene. Compared with the well-known 3-acetyl-deoxynivalenol (3-ADON), it lacks the keto group at C-8 and hence is a type A trichothecene. Wheat ears inoculated with the isolated strains revealed a 10-fold higher contamination with its deacetylated form, named NX-3, (up to 540 mg kg(-1) ) compared with NX-2. The toxicities of the novel mycotoxins were evaluated utilizing two in vitro translation assays and the alga Chlamydomonas reinhardtii. NX-3 inhibits protein biosynthesis to almost the same extent as the prominent mycotoxin deoxynivalenol, while NX-2 is far less toxic, similar to 3-ADON. Genetic analysis revealed a different TRI1 allele in the N-isolates, which was verified to be responsible for the difference in hydroxylation at C-8.
Christian Doppler Laboratory for Mycotoxin Metabolism, Center for Analytical Chemistry, Department for Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences, Vienna (BOKU), Konrad Lorenz Str. 20, 3430, Tulln, Austria.
Elisabeth
E
Varga
Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna (BOKU), Konrad Lorenz Str. 24, 3430, Tulln, Austria.
Gerlinde
G
Wiesenberger
Institute of Applied Synthetic Chemistry, Vienna University of Technology, Getreidemarkt 9/163-OC, 1060, Vienna, Austria.
Christian
C
Hametner
Bacterial Foodborne Pathogens and Mycology Research Unit, National Center for Agricultural Utilization Research, United States Department of Agriculture, 1815 N. University Street, Peoria, IL, 61604, USA.
Todd J
TJ
Ward
Department of Plant Pathology, University of Minnesota, 1991 Upper Buford Circle, St Paul, MN, 55108, USA.
Yanhong
Y
Dong
Christian Doppler Laboratory for Mycotoxin Metabolism, Center for Analytical Chemistry, Department for Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences, Vienna (BOKU), Konrad Lorenz Str. 20, 3430, Tulln, Austria.
Denise
D
Schöfbeck
Bacterial Foodborne Pathogens and Mycology Research Unit, National Center for Agricultural Utilization Research, United States Department of Agriculture, 1815 N. University Street, Peoria, IL, 61604, USA.
Susan
S
McCormick
Department of Plant Pathology, University of Minnesota, 1991 Upper Buford Circle, St Paul, MN, 55108, USA.
Karen
K
Broz
Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna (BOKU), Konrad Lorenz Str. 24, 3430, Tulln, Austria.
Romana
R
Stückler
Christian Doppler Laboratory for Mycotoxin Metabolism, Center for Analytical Chemistry, Department for Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences, Vienna (BOKU), Konrad Lorenz Str. 20, 3430, Tulln, Austria.
Rainer
R
Schuhmacher
Christian Doppler Laboratory for Mycotoxin Metabolism, Center for Analytical Chemistry, Department for Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences, Vienna (BOKU), Konrad Lorenz Str. 20, 3430, Tulln, Austria.
Rudolf
R
Krska
Department of Plant Pathology, University of Minnesota, 1991 Upper Buford Circle, St Paul, MN, 55108, USA.|Agriculture Research Service, United States Department of Agriculture, 1551 Lindig Avenue, St Paul, MN, 55108, USA.
H Corby
HC
Kistler
Christian Doppler Laboratory for Mycotoxin Metabolism, Center for Analytical Chemistry, Department for Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences, Vienna (BOKU), Konrad Lorenz Str. 20, 3430, Tulln, Austria.
Franz
F
Berthiller
Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna (BOKU), Konrad Lorenz Str. 24, 3430, Tulln, Austria.
Gerhard
G
Adam
D002853:Chromatography, Liquid; D002523:Edible Grain / Q000382:microbiology*; D005506:Food Contamination / Q000032:analysis*; D005670:Fusarium / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D005838:Genotype; D009183:Mycotoxins / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D009656:North America; D012275:Oryza / Q000382:microbiology; D010935:Plant Diseases / Q000382:microbiology*; D014255:Trichothecenes / Q000737:chemistry / Q000378:metabolism; D014908:Triticum / Q000382:microbiology
D009183:Mycotoxins; D014255:Trichothecenes; C063751:12,13-epoxytrichothec-9-ene; C043247:3-acetyldeoxynivalenol; C038972:acetyldeoxynivalenol; C007262:deoxynivalenol