Species composition of and fumonisin production by the Fusarium fujikuroi species complex isolated from Korean cereals

• Published in: International journal of food microbiology 2018-02, Vol.267, p.62-69
• Main Authors: Choi, Jung-Hye, Lee, Seolhee, Nah, Ju-Young, Kim, Hee-Kyoung, Paek, Ji-Seon, Lee, Soohyung, Ham, Hyeonheui, Hong, Sung Kee, Yun, Sung-Hwan, Lee, Theresa
• Format: Article
• Language: English
• Subjects: Agricultural production; Barley; Biodiversity; Biosynthesis; Cereal; Cereals; Contamination; Corn; Deoxyribonucleic acid; DNA; DNA-directed RNA polymerase; Edible Grain - chemistry; Edible Grain - microbiology; Elongation; F. fujikuroi; Fumonisin; Fumonisins; Fumonisins - analysis; Fumonisins - chemistry; Fumonisins - metabolism; Fusarium; Fusarium - classification; Fusarium - genetics; Fusarium - isolation & purification; Fusarium fujikuroi; Fusarium fujikuroi species complex; Fusarium proliferatum; Fusarium verticillioides; Nucleotide sequence; Peptide Elongation Factor 1 - genetics; Phylogeny; Ribonucleic acid; Rice; RNA; RNA polymerase; RNA polymerase II; RNA Polymerase II - genetics; Soybeans; Species composition; Toxins; Translation elongation
• ISSN: 0168-1605; 1879-3460
• DOI: 10.1016/j.ijfoodmicro.2017.12.006

To assess the risk of fumonisin contamination in Korean cereals, we isolated colonies of the Fusarium fujikuroi species complex (FFSC) from barley, maize, rice and soybean samples from 2011 to 2015. A total of 878 FFSC strains were isolated mostly from maize and rice, and species identity of the isolates were determined using the DNA sequence of the translation elongation factor 1-α (TEF-1α) and RNA polymerase II (RPB2) genes. Fusaria recovered from Korean cereals included F. fujikuroi (317 isolates and a frequency of 36%), F. proliferatum (212 isolates and 24.1%), F. verticillioides (170 isolates and 19.4%), F. concentricum (86 strains and 9.8%), F. andiyazi (56 isolates and 6.4%), F. subglutinans (28 isolates and 3.2%), F. thapsinum (5 isolates and 0.6%), and F. circinatum (2 isolates and 0.2%). The rice samples were dominated by F. fujikuroi (47.4%), F. proliferatum (27.3%), and F. concentricum (15.1%), whereas maize samples were dominated by F. verticillioides (33.9%), F. fujikuroi (25.3%), and F. proliferatum (21.1%). A phylogenetic analysis of 70 representative isolates demonstrated that each species was resolved as genealogically exclusive in the ML tree. Fumonisin production potential was evaluated using a PCR assay for the fumonisin biosynthesis gene, FUM1 in all of the isolates. Most of the isolates tested (94%) were positive for FUM1. All of the isolates assigned to F. fujikuroi, F. proliferatum, F. verticillioides and F. thapsinum were positive for FUM1 irrespective of their host origin. Seventy-seven representative isolates positive for FUM1 were examined for fumonisin production in rice medium. The majority of F. proliferatum (26/27, 96.3%), F. verticillioides (16/17, 94.1%) and F. fujikuroi (19/25, 76.0%) produced both FB1 and FB2. Notably, 16 of 19 fumonisin-producing F. fujikuroi produced >1000μg/g of fumonisins (FB1+FB2) in rice medium, which is higher than that in previous reports. These results suggest that F. fujikuroi can produce high levels of fumonisins similar to F. verticillioides and F. proliferatum. •Cereal samples were mostly colonized by F. fujikuroi, F. proliferatum, and F. verticillioides.•Most strains of F. proliferatum, F. verticillioides, and F. fujikuroi produced both FB1 and FB2 in rice medium.•Most of the F. fujikuroi tested produced high levels of fumonisins.