An insight into the distribution, genetic diversity, and mycotoxin production of Aspergillus section Flavi in soils of pistachio orchards.

Mojdeh Jamali (1) , Mohammad-Ali Ebrahimi (2) , Morteza Karimipour (3) , Masoomeh Shams-Ghahfarokhi (4) , Navid Dinparast-Djadid (3) , Sanaz Kalantari (1) , Yones Pilehvar-Soltanahmadi (1) , Akram Amani (1) , Mehdi Razzaghi-Abyaneh (1)

1 Institut Pasteur d'Iran
2 Department of Agricultural Biotechnology
3 Biotechnology Research Center
4 Department of Mycology

In the present study, 193 Aspergillus strains were isolated from a total of 100 soil samples of pistachio orchards, which all of them were identified as Aspergillus flavus as the most abundant species of Aspergillus section Flavi existing in the environment. Approximately 59%, 81%, and 61% of the isolates were capable of producing aflatoxins (AFs), cyclopiazonic acid (CPA), and sclerotia, respectively. The isolates were classified into four chemotypes (I to IV) based on the ability to produce AFs and CPA. The resulting dendrogram of random amplified polymorphic DNA (RAPD) analysis of 24 selected A. flavus isolates demonstrated the formation of two separate clusters. Cluster 1 contained both aflatoxigenic and non-aflatoxigenic isolates (17 isolates), whereas cluster 2 comprised only aflatoxigenic isolates (7 isolates). All the isolates of cluster 2 produced significantly higher levels of AFs than those of cluster 1 and the isolates that produced both AFB(1) and AFB(2) were found only in cluster 2. RAPD genotyping allowed the differentiation of A. flavus from Aspergillus parasiticus as a closely related species within section Flavi. The present study has provided for the first time the relevant information on distribution and genetic diversity of different A. flavus populations from nontoxigenic to highly toxigenic enable to produce hazardous amounts of AFB(1) and CPA in soils of pistachio orchards. These fungi, either toxigenic or not-toxigenic, should be considered as potential threats for agriculture and public health.

Mots clés: distribution; genetic diversity; mycotoxin production; Aspergillus section Flavi; pistachio orchards

Domaines: Génétique animale

Mojdeh Jamali, Mohammad-Ali Ebrahimi, Morteza Karimipour, Masoomeh Shams-Ghahfarokhi, Navid Dinparast-Djadid, et al.. An insight into the distribution, genetic diversity, and mycotoxin production of Aspergillus section Flavi in soils of pistachio orchards.. Folia Microbiologica, 2012, 57 (1), pp.27-36. ⟨10.1007/s12223-011-0090-5⟩. ⟨pasteur-00755314⟩