LAMP-PCR detection of ochratoxigenic Aspergillus species collected from peanut kernel.
Over the last decade, ochratoxin A (OTA) has been widely described and is ubiquitous in several agricultural products. Ochratoxins represent the second-most important mycotoxin group after aflatoxins. A total of 34 samples were surveyed from 3 locations, including Mecca, Madina, and Riyadh, Saudi Arabia, during 2012. Fungal contamination frequency was determined for surface-sterilized peanut seeds, which were seeded onto malt extract agar media. Aspergillus niger (35%), Aspergillus ochraceus (30%), and Aspergillus carbonarius (25%) were the most frequently observed Aspergillius species, while Aspergillus flavus and Aspergillus phoenicis isolates were only infrequently recovered and in small numbers (10%). OTA production was evaluated on yeast extract sucrose medium, which revealed that 57% of the isolates were A. niger and 60% of A. carbonarius isolates were OTA producers; 100% belonged to A. ochraceus. Only one isolate, morphologically identified as A. carbonarius, and 3 A. niger isolates unstably produced OTA. A polymerase chain reaction (PCR)-based identification and detection assay was used to identify A. ochraceus isolates. Using the primer sets OCRA1/OCRA2, 400-base pair PCR fragments were produced only when genomic DNA from A. ochraceus isolates was used. Recently, the loop-mediated isothermal amplification assay using recombinase polymerase amplification chemistry was used for A. carbonarius and A. niger DNA identification. As a non-gel-based technique, the amplification product was directly visualized in the reaction tube after adding calcein for naked-eye examination.
Department of Biology, College of Science, King Faisal University, AlHassa, Saudi Arabia Plxha@kfu.edu.sa.
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Al-Sheikh
D010367:Arachis / Q000382:microbiology*; D001230:Aspergillus / Q000235:genetics / Q000302:isolation & purification*; D009793:Ochratoxins / Q000633:toxicity*; D016133:Polymerase Chain Reaction / Q000379:methods*; D012529:Saudi Arabia; D013698:Templates, Genetic
D009793:Ochratoxins; C025589:ochratoxin A