Molecular strategy for identification in Aspergillus section Flavi

FEMS Microbiol Lett. 2010 Mar;304(2):157-68. doi: 10.1111/j.1574-6968.2009.01890.x.

Abstract

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.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aspergillus / classification*
  • Aspergillus / genetics*
  • Base Sequence
  • DNA Fingerprinting / methods
  • DNA, Fungal / genetics*
  • DNA, Fungal / metabolism
  • Deoxyribonucleases, Type II Site-Specific / metabolism
  • Molecular Sequence Data
  • Mycology / methods*
  • Polymerase Chain Reaction / methods*
  • Polymorphism, Restriction Fragment Length*
  • Random Amplified Polymorphic DNA Technique / methods*

Substances

  • DNA, Fungal
  • CCCGGG-specific type II deoxyribonucleases
  • Deoxyribonucleases, Type II Site-Specific