Ochratoxin production and taxonomy of the yellow aspergilli (Aspergillus section Circumdati)

Abstract

Aspergillus section Circumdati or the Aspergillus ochraceus group, includes species with rough walled stipes, biseriate conidial heads, yellow to ochre conidia and sclerotia that do not turn black. Several species are able to produce mycotoxins including ochratoxins, penicillic acids, and xanthomegnins. Some species also produce drug lead candidates such as the notoamides. A polyphasic approach was applied using morphological characters, extrolite data and partial calmodulin, β-tubulin and ITS sequences to examine the evolutionary relationships within this section. Based on this approach the section Circumdati is revised and 27 species are accepted, introducing seven new species: A. occultus, A. pallidofulvus, A. pulvericola, A. salwaensis, A. sesamicola, A. subramanianii and A. westlandensis. In addition we correctly apply the name A. fresenii (≡ A. sulphureus (nom. illeg.)). A guide for the identification of these 27 species is provided. These new species can be distinguished from others based on morphological characters, sequence data and extrolite profiles. The previously described A. onikii and A. petrakii were found to be conspecific with A. ochraceus, whilst A. flocculosus is tentatively synonymised with A. ochraceopetaliformis, despite extrolite differences between the two species. Based on the extrolite data, 13 species of section Circumdati produce large amounts of ochratoxin A: A. affinis, A. cretensis, A. fresenii, A. muricatus, A. occultus, A. ochraceopetaliformis (A. flocculosus), A. ochraceus, A. pseudoelegans, A. pulvericola, A. roseoglobulosus, A. sclerotiorum, A. steynii and A. westerdijkiae. Seven additional species produce ochratoxin A inconsistently and/or in trace amounts: A. melleus, A. ostianus, A. persii, A. salwaensis, A. sesamicola, A. subramanianii and A. westlandensis. The most important species regarding potential ochratoxin A contamination in agricultural products are A. ochraceus, A. steynii and A. westerdijkiae.

A critical review of producers of small lactone mycotoxins: patulin, penicillic acid and moniliformin

“…Circumdati (Frisvad and Samson, 2000;Frisvad et al, 2004a;Visagie et al, 2014a). One can therefore expect a mycotoxin cocktail in mouldy cereals consisting of citrinin, ochratoxin A, penicillic acid, verrucosidin, nephrotoxic glycopeptides, xanthomegnin, viomellein, vioxanthin, moniliformin, and penitrem A when associated storage fungal species, such as P. verrucosum, P. aurantiogriseum, P. polonicum, P. viridicatum, P. cyclopium and Penicillium freii have grown on those cereals in a worst case scenario HallasMøller et al, 2016;Lund and Frisvad, 1994).…”

“…One can therefore expect a mycotoxin cocktail in mouldy cereals consisting of citrinin, ochratoxin A, penicillic acid, verrucosidin, nephrotoxic glycopeptides, xanthomegnin, viomellein, vioxanthin, moniliformin, and penitrem A when associated storage fungal species, such as P. verrucosum, P. aurantiogriseum, P. polonicum, P. viridicatum, P. cyclopium and Penicillium freii have grown on those cereals in a worst case scenario HallasMøller et al, 2016;Lund and Frisvad, 1994). Most species in Aspergillus section Circumdati, such as Aspergillus westerdijkiae, Aspergillus steynii and Aspergillus ochraceus also produce one or more of the mycotoxins ochratoxin A, penicillic acid, xanthomegnin, viomellein and vioxanthin (Visagie et al, 2014a). Penicillic acid has been found in many sections of Penicillium, including Brevicompacta, Canescentia, Chrysogena, Exilicaulis, Fasciculata, LanataDivaricata, Ramosa, Roquefortorum and Turbatum, so this is found in many phylogenetic groups of Penicillium.…”

“…The two toxins together also increase degeneration in kidney proximal tubules (Klarić et al, 2013;Stoev, 2013;Stoev and Denev, 2013). The synergistic worm toxicity of penicilllic acid and ochratoxin A is interesting as the fungi producing these combinations of toxins are often growing in corn and other cereals (Lund and Frisvad, 1994;Visagie et al, 2014a). Other studies have only shown an additive toxic effect on porcine lymphocytes of ochratoxin A and penicillic acid (Bernhoft et al, 2004;Stoev et al, 1999).…”

“…Other studies have only shown an additive toxic effect on porcine lymphocytes of ochratoxin A and penicillic acid (Bernhoft et al, 2004;Stoev et al, 1999). These two mycotoxins are often co-occurring as Aspergillus from section Circumdati produce penicillic acid and ochratoxin simultaneously in most species from that section (Visagie et al, 2014a). Furthermore, species from Penicillium section Fasciculata series Viridicata and Verrucosa co-occur in cereals (Lund and Frisvad, 1995), and thus penicillic acid and ochratoxin A are also both found often in contaminated cereals.…”

“…It was the aim of this review to revise the lists of producers of patulin, penicillic acid and moniliformin according to the most recent taxonomic treatments of the genera Aspergillus (Chen et al, 2016a(Chen et al, ,b, 2017Frisvad, 2015;Frisvad and Larsen, 2015;Hubka et al, 2015Hubka et al, , 2016Jurjevics et al, 2015;Kocsubé et al, 2016;Samson et al, 2011aSamson et al, ,b, 2014Samson et al, , 2017Sklenář et al, 2017;Varga et al, 2007aVarga et al, ,b, 2011aVisagie et al, 2014aVisagie et al, , 2017, Penicillium Houbraken et al, 2016;Visagie et al, 2014b) and Fusarium (Aoki et al, 2014;Burgess, 2014;Gerlach and Nirenberg, 1982;Lesley and Summerell, 2016;Nelson et al, 1983), as correct species-mycotoxin relations are important for prevention of mycotoxin formation in foods, feeds and biotechnological products.…”