Ochratoxin A producing Penicillium verrucosum isolates from cereals reveal large AFLP fingerprinting variability.
OBJECTIVE
To examine if molecular amplified fragment length polymorphism (AFLP) fingerprinting of the only ochratoxin A-producing species in European cereals, Penicillium verrucosum, can be used as a method in hazard analysis using critical control points (HACCP).


RESULTS
A total of 321 isolates of P. verrucosum were isolated from ochratoxin A-contaminated cereals from Denmark (oats), UK (wheat and barley) and Sweden (wheat). Of these, 236 produced ochratoxin A as determined by thin layer chromatography; 185 ochratoxin A-producing isolates were selected for AFLP fingerprinting. A total of 138 isolates had unique AFLP patterns, whereas 52 isolates could be allocated to small groups containing from two to four isolates with similar AFLP patterns. A total of 155 clones were found among the 185 P. verrucosum isolates, thus 84% of the isolates may represent different genets of P. verrucosum. As the few isolates that were grouped often came from the same farm, and those groups that contained AFLP-identical isolates from different countries were morphotypically different. On single farms up to 35 clones were found. The few groups of ramets from the same genet indicated that a HACCP approach based on clones may require a very large number of AFLP analysis to work in practice, we recommend basing the HACCP approach on the actual species P. verrucosum. A more detailed characterization should rather be based on the profile of species present at different control points, or analysis of the mycotoxins ochratoxin A and citrinin in the isolates. Examination of 86 isolates with HPLC and diode array detection of P. verrucosum showed that 66% produced ochratoxin A, 87% produced citrinin, 92% produced verrucin and 100% produced verrucolone.


CONCLUSIONS
Among 184 ochratoxin A-producing Penicillium verrucosum, 155 clonal lineages were indicated by AFLP fingerprinting, indicating a high genetical diversity, yet the species P. verrucosum is phenotypically distinct and valid.


CONCLUSIONS
AFLP fingerprinting of Penicillium verrucosum indicates that genetic recombination takes place in this fungus.
Frisvad
J C
JC
Center for Microbial Biotechnology, Biocentrum-DTU, Søltofts Plads, Technical University of Denmark, Lyngby, Denmark. jcf@biocentrum.dtu.dk
Lund
F
F
Elmholt
S
S
D018554:Avena; D016172:DNA Fingerprinting; D003718:Denmark; D002523:Edible Grain; D005800:Genes, Fungal; D014644:Genetic Variation; D001467:Hordeum; D007218:Industrial Microbiology; D009793:Ochratoxins / Q000096:biosynthesis*; D010407:Penicillium / Q000235:genetics* / Q000378:metabolism*; D011110:Polymorphism, Genetic; D013548:Sweden; D014908:Triticum; D006113:United Kingdom
D009793:Ochratoxins; C025589:ochratoxin A