title: Quantification of Tri5 gene, expression, and deoxynivalenol production during the malting of barley.
abstract: Fusarium can survive, grow, and produce mycotoxins during malting. We evaluated the percentage of barley kernels infected with Fusarium (FI) and deoxynivalenol (DON) concentration in three barley treatments (high-quality, naturally infected, and Fusarium graminearum inoculated barley) during various stages of malting. We also applied real-time polymerase chain reaction (real-time PCR) and real-time reverse transcriptase PCR (real-time RT-PCR) methods to quantify trichothecene-producing (Tri5) DNA concentration and expression, respectively. We observed that FI significantly (P<0.05) increased during the germination stage of malting in all barley treatments. Temperatures of 49°C and higher during kilning reduced the FI in high-quality barley treatments, but for inoculated treatments temperatures in excess of 60°C were needed to reduce FI. The Tri5 DNA concentration ranged from non-detectable to 3.9 ng/50mg, 0.1 to 109.8 ng/50mg and 3.4 to 397.5 ng/50 mg in malted high-quality, inoculated and naturally infected barley treatments respectively. Strong gene expression (Tri5) in naturally infected barley treatments was found during the third day of germination, when compared to high-quality and inoculated barley treatments during malting. Deoxynivalenol was present even at high kilning temperatures, as DON is heat stable. The average DON concentration ranged from non-detectable to 0.1 μg/g, non-detectable to 1.1 μg/g, and 1.5 to 45.9 μg/g during various stages of malting in high-quality, inoculated and infected barley and malt samples respectively. Overall, the last 2 days of germination and initial stages of kilning were peak stages for FI, Tri5 gene production, Tri5 gene expression and DON production.
authors.affiliation: Department of Veterinary and Microbiological Sciences, North Dakota State University, Dept. 7690, PO Box 6050, Fargo, ND 58108-6050, United States.
authors.forename: Anuradha
authors.initials: A
authors.lastname: Vegi
authors.forename: Paul
authors.initials: P
authors.lastname: Schwarz
authors.forename: Charlene E
authors.initials: CE
authors.lastname: Wolf-Hall
mesh_terms: D002523:Edible Grain / Q000382:microbiology; D005516:Food Microbiology; D005656:Fungal Proteins / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D005670:Fusarium / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D015870:Gene Expression; D005800:Genes, Fungal; D018525:Germination; D001467:Hordeum / Q000382:microbiology*; D006358:Hot Temperature; D009183:Mycotoxins / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014255:Trichothecenes / Q000032:analysis / Q000378:metabolism*
chemical_list: D005656:Fungal Proteins; D009183:Mycotoxins; D014255:Trichothecenes; C007262:deoxynivalenol