Molecular detection of ochratoxigenic Aspergillus species isolated from coffee beans in Saudi Arabia.
Ten fungal isolates from coffee beans were morphologically identified as Aspergillus niger, A. ochraceus and A. carbonari-us (N = 5, 3, and 2, respectively). Only one isolate, morphologically identified as A. niger, was unable to produce ochratoxin A (OTA). This may be a new species in the Aspergillus section Nigri. OTA levels in all the other isolates were above the limit of detection (0.15 mg/kg). Based on microsatellite-primed PCR (MP-PCR) profiles, using three microsatellite primers, three main groups were obtained by UPGMA cluster analysis: A. niger, A. ochraceus and A. carbonarius. A clear-cut association was found between the MP-PCR genotype and the ability to produce OTA. Using the primer pairs OCRA1/OCRA2, a single fragment of about 400 bp was amplified only when genomic DNA from the A. ochraceus isolates was used.
King Saud University, College of Science, Botany and Microbiology Department, Riyadh, Saudi Arabia.
M A
MA
Moslem
A
A
Mashraqi
K A
KA
Abd-Elsalam
A H
AH
Bahkali
M A
MA
Elnagaer
D001230:Aspergillus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D001483:Base Sequence; D002851:Chromatography, High Pressure Liquid; D016000:Cluster Analysis; D003069:Coffee / Q000382:microbiology*; D017931:DNA Primers; D004271:DNA, Fungal / Q000235:genetics*; D004587:Electrophoresis, Agar Gel; D018895:Microsatellite Repeats / Q000235:genetics; D009793:Ochratoxins / Q000032:analysis* / Q000096:biosynthesis; D016133:Polymerase Chain Reaction; D012529:Saudi Arabia; D013045:Species Specificity
D003069:Coffee; D017931:DNA Primers; D004271:DNA, Fungal; D009793:Ochratoxins; C025589:ochratoxin A