Biodiversity of Aspergillus species in some important agricultural products

Abstract

The genus Aspergillus is one of the most important filamentous fungal genera. Aspergillus species are used in the fermentation industry, but they are also responsible of various plant and food secondary rot, with the consequence of possible accumulation of mycotoxins. The aflatoxin producing A. flavus and A. parasiticus, and ochratoxinogenic A. niger, A. ochraceus and A. carbonarius species are frequently encountered in agricultural products. Studies on the biodiversity of toxigenic Aspergillus species is useful to clarify molecular, ecological and biochemical characteristics of the different species in relation to their different adaptation to environmental and geographical conditions, and to their potential toxigenicity. Here we analyzed the biodiversity of ochratoxin producing species occurring on two important crops: grapes and coffee, and the genetic diversity of A. flavus populations occurring in agricultural fields. Altogether nine different black Aspergillus species can be found on grapes which are often difficult to identify with classical methods. The polyphasic approach used in our studies led to the identification of three new species occurring on grapes: A. brasiliensis, A. ibericus, and A. uvarum. Similar studies on the Aspergillus species occurring on coffee beans have evidenced in the last five years that A. carbonarius is an important source of ochratoxin A in coffee. Four new species within the black aspergilli were also identified in coffee beans: A. sclerotioniger, A. lacticoffeatus, A. sclerotiicarbonarius, and A. aculeatinus. The genetic diversity within A. flavus populations has been widely studied in relation to their potential aflatoxigenicity and morphological variants L- and S-strains. Within A. flavus and other Aspergillus species capable of aflatoxin production, considerable diversity is found. We summarise the main recent achievements in the diversity of the aflatoxin gene cluster in A. flavus populations, A. parasiticus and the non-toxigenic A. oryzae. Studies are needed in order to characterise the aflatoxin biosynthetic genes in the new related taxa A. minisclerotigenes and A. arachidicola.

Transcriptomic and morphological profiling of Aspergillus fumigatus Af293 in response to antifungal activity produced by Lactobacillus plantarum 16

“…Rhizopus stolonifer is the common black bread mould, which is also responsible for the post-harvest decay of a wide range of fruits, including strawberries and stone fruits (Pitt & Hocking, 1999). In addition, various species of the genus Aspergillus pose a threat to the food industry as they contaminate agricultural products during pre-harvest, harvest, processing and storage, and most notably produce aflatoxins and ochratoxin A (Perrone et al, 2007). Aspergillus fumigatus is of particular concern as it is the most common aetiological agent of invasive human aspergillosis, predominantly affecting immunocompromised individuals (Dagenais & Keller, 2009).…”

Toxigenic mycobiota and mycotoxins in shrimp feed

“…These strains can be classified as atypical A. flavus (TRAN-DINH et al, 1999;PILDAÍN et al, 2004;PERRONE et al, 2007). This strain isolated presents all macroscopic and microscopic morphological characteristics of A. flavus differentiating morphologically A. parasiticus (KLICH, 2002).…”

“…Phylogenetic studies of A. flavus showed that it consists of two subgroups (I and II) (TRAN-DINH et al, 1999). Most group I strains produced Aflatoxin B, and most group II strains produced both Aflatoxin B and Aflatoxin G (PILDAÍN et al 2004;PERRONE et al, 2007).…”

Chemical composition and antifungal activity of Mentha spicata L. plant from Sulaimaniyah in Iraq

“…It causes many diseases on plant because of its ability to produce hydrolytic and oxidative enzymes which could involve in breakdown of plant lignocellulos [24]. It is known as a main causative agent of black mold and rot disease on different fruits and vegetables also commonly used in food industry because of production of extracellular organic acids materials [24,23,22,27]. A. niger has been tagged with the generally recognized as safe status from the US Food and Drug Administration [25].…”