Rapid Detection Method for Fusaric Acid-producing Species of Fusarium by PCR

Paek

The Plant Pathology Journal

et al. 2016

Self Cite

Fusarium graminearum species complex (FGSC) causes Fusarium head blight in small grain cereals. To date, four species (F. graminearum, F. asiaticum, F. boothii, and F. meridionale ) belonging to FGSC frequently occur in Korean cereals. In addition, we first reported the occurrence of additional species (F. vorosii ) within FGSC, which was isolated from barley, corn, and rice in Korea. Phylogenetic analysis of the Fusarium isolates of this group using combined multi-gene sequences confirmed species identification. Moreover, the macroconidia produced by these isolates were morphologically similar to those of the F. vorosii holotype. Chemical analysis indicated that the F. vorosii isolates produced various trichothecenes such as nivalenol and deoxynivalenol with their acetyl derivatives along with zearalenone. Pathogenicity tests demonstrated that all of the F. vorosii isolates examined were pathogenic on barley, corn, and rice with variation in aggressiveness. This study is the first report of F. vorosii in Korean cereals, their pathogenicity towards barley and corn, and their ability to produce trichothecenes and zearalenone.

Section: Methodsmentioning

confidence: 99%

Occurrence of Toxigenic Fusarium vorosii among Small Grain Cereals in Korea

Paek

The Plant Pathology Journal

et al. 2016

Self Cite

Mycobiota of ground red pepper and their aflatoxigenic potential

Ham

Kim

et al. 2016

J Microbiol.

To investigate contamination of ground red pepper with fungi and mycotoxin, we obtained 30 ground red pepper samples from 15 manufacturers in the main chili-pepper-producing areas in Korea. Fungal contamination was evaluated by spreading diluted samples on potato dextrose agar plates. The total fungi counts ranged from 0 to 7.3 × 10 CFU/g. In the samples, the genus Aspergillus had the highest incidence, while Paecilomyces was isolated most frequently. The next most frequent genera were Rhizopus, Penicillium, Cladosporium, and Alternaria. Within Aspergillus, A. ruber was predominant, followed by A. niger, A. amstelodami, A. ochraceus, A. terreus, A. versicolor, A. flavus, and A. fumigatus. The samples were analyzed for aflatoxins, ochratoxin A, and citrinin by ultra-perfomance liquid chromatography (UPLC) with a fluorescence detector. Ochratoxin A was detected from three samples at 1.03‒2.08 μg/kg, whereas no aflatoxins or citrinin were detected. To test the potential of fungal isolates to produce aflatoxin, we performed a PCR assay that screened for the norB-cypA gene for 64 Aspergillus isolates. As a result, a single 800-bp band was amplified from 10 A. flavus isolates, and one Aspergillus sp. isolate. UPLC analyses confirmed aflatoxin production by nine A. flavus isolates and one Aspergillus sp. isolate, which produced total aflatoxins at 146.88‒909.53 μg/kg. This indicates that continuous monitoring of ground red pepper for toxigenic fungi is necessary to minimize mycotoxin contamination.

Fusarium algeriense, sp. nov., a novel toxigenic crown rot pathogen of durum wheat from Algeria is nested in the Fusarium burgessii species complex

et al. 2017

A novel crown rot pathogen of wheat discovered during pathogen surveys in Algeria in 2014 and 2015 is formally described as Fusarium algeriense. Multilocus molecular phylogenetic data resolved the eight isolates of this pathogen as a genealogically exclusive species lineage in the F. burgessii species complex. The previously described species of this complex, F. burgessii and F. beomiforme, produce abundant chlamydospores in culture, and their optimal temperature for growth is 30 C. In comparison, F. algeriense did not produce chlamydospores under the conditions tested and its optimal temperature for growth is 25 C. Furthermore, F. algeriense differs from F. burgessii because it does not produce polyphialides and F. beomiforme, because it does not produce globose-to-napiform conidia in the aerial mycelium. Isolates of F. algeriense induced moderate crown rot on the susceptible spring wheat cultivar Norm in a temperature-controlled incubator. Fusarium burgessii and F. beomiforme, in contrast, only induced mild symptoms of this disease. BLASTn searches of the whole-genome sequence of F. algeriense strains NRRL 66647 and 66648, using homologs of genes that are responsible for synthesis of toxic secondary metabolites, indicated that they have the potential to produce several polyketide and non-ribosomal peptide-derived mycotoxins. However, moniliformin and 2-AOD-ol (2-amino-14,16-dimethyloctadecan-3-ol) were the only mycotoxins detected by liquid chromatography-mass spectrometry (LC-MS) analyses of strains cultivated in vitro on a solid medium. A polymerase chain reaction (PCR) assay for MAT idiomorph revealed that MAT1-1 and MAT1-2 strains of F. algeriense were present in Algeria, which suggests this pathogen might possess a heterothallic sexual reproductive mode.