Molecular strategy for identification in Aspergillus section Flavi.
Aspergillus flavus is one of the most common contaminants that produces aflatoxins in foodstuffs. It is also a human allergen and a pathogen of animals and plants. Aspergillus flavus is included in the Aspergillus section Flavi that comprises 11 closely related species producing different profiles of secondary metabolites. A six-step strategy has been developed that allows identification of nine of the 11 species. First, three real-time PCR reactions allowed us to discriminate four groups within the section: (1) A. flavus/Aspergillus oryzae/Aspergillus minisclerotigenes/Aspergillus parvisclerotigenus; (2) Aspergillus parasiticus/Aspergillus sojae/Aspergillus arachidicola; (3) Aspergillus tamarii/Aspergillus bombycis/Aspergillus pseudotamarii; and (4) Aspergillus nomius. Secondly, random amplification of polymorphic DNA (RAPD) amplifications or SmaI digestion allowed us to differentiate (1) A. flavus, A. oryzae and A. minisclerotigenes; (2) A. parasiticus, A. sojae and A. arachidicola; (3) A. tamarii, A. bombycis and A. pseudotamarii. Among the 11 species, only A. parvisclerotigenus cannot be differentiated from A. flavus. Using the results of real-time PCR, RAPD and SmaI digestion, a decision-making tree was drawn up to identify nine of the 11 species of section Flavi. In contrast to conventional morphological methods, which are often time-consuming, the molecular strategy proposed here is based mainly on real-time PCR, which is rapid and requires minimal handling.
Godet
Marie
M
Mycothèque de l'Université catholique de Louvain (MUCL), Unité de Microbiologie, Université catholique de Louvain, Louvain-la-Neuve, Belgium. marie.godet@uclouvain.be
Munaut
Françoise
F
D001230:Aspergillus / Q000145:classification* / Q000235:genetics*; D001483:Base Sequence; D016172:DNA Fingerprinting / Q000379:methods; D004271:DNA, Fungal / Q000235:genetics* / Q000378:metabolism; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism; D008969:Molecular Sequence Data; D009172:Mycology / Q000379:methods*; D016133:Polymerase Chain Reaction / Q000379:methods*; D012150:Polymorphism, Restriction Fragment Length; D019105:Random Amplified Polymorphic DNA Technique / Q000379:methods*
D004271:DNA, Fungal; C025651:CCCGGG-specific type II deoxyribonucleases; D015252:Deoxyribonucleases, Type II Site-Specific