Differentiation between Aspergillus flavus and Aspergillus parasiticus isolates originated from wheat

Nikolić, Milica; Nikolić, Ana; Jauković, Marko; Savic, Iva; Petrović, Tanja; Bagi, Ferenc; Stankоvić, Slavica

doi:10.2298/gensr1801143n

Cited by 5 publications

(3 citation statements)

References 26 publications

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“…Our findings were similar to those reported by ( Kana et al 2013 ), which indicate that all A. flavi isolates recovered from all the commodities (feedstuffs and animal feed) were A. flavus . In contrast, other studies ( Stanković et al 2015 ; Nikolic et al 2018 ) found the presence of A. parasiticus on wheat kernels and corn. This difference may result from the geographic isolation and the local atmosphere conditions (temperature, humidity), which might cause shifts in mycobiota distribution and composition of cereals observed among different regions.…”

Section: Resultsmentioning

confidence: 76%

“…Previous studies indicated that PCR-IGS-RFLP using restriction enzymes that cleave the PCR products into sub-fragments are valuable tools for detecting and differentiating between A. flavus and A. parasiticus (El Khoury et al 2011;Nikolic et al 2018;Lavkor 2020). Therefore, we used the restriction endonuclease BglII to digest the four PCR products.…”

Section: Resultsmentioning

confidence: 99%

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Molecular Characterization of Aspergillus flavus Strains Isolated from Animal Feeds

Saber

Chebloune

Moussaoui

2022

Polish Journal of Microbiology

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Aflatoxin (AF)-producing fungi such as Aspergillus flavus commonly contaminate animal feeds, causing high economic losses. A. flavus is the most prevalent and produces AFB1, a potent mutagen, and carcinogen threatening human and animal health. Aspergillaceae is a large group of closely related fungi sharing number of morphological and genetic similarities that complicate the diagnosis of highly pathogenic strains. We used here morphological and molecular assays to characterize fungal isolates from animal feeds in Southwestern Algeria. These tools helped to identify 20 out of 30 Aspergillus strains, and 15 of them belonged to the Aspergillus section Flavi. Further analyses detected four out of 15 as belonging to Aspergillus flavus-parasiticus group. PCR targeting the AF genes’ aflR-aflS(J) intergenic region amplified a single 674 bp amplicon in all four isolates. The amplicons were digested with a BglII endonuclease, and three specific fragments were observed for A. flavus but A. parasitucus lacked two typical fragments. Sequencing data of four amplicons confirmed the presence of the two BglII restriction sites yielding the three fragments, confirming that all four strains were A. flavus. In addition, this analysis illustrated the genetic variability within the A. flavus strains.

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Section: Resultsmentioning

confidence: 76%

Section: Resultsmentioning

confidence: 99%

Molecular Characterization of Aspergillus flavus Strains Isolated from Animal Feeds

Saber

Chebloune

Moussaoui

2022

Polish Journal of Microbiology

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“…Certain mycotoxins can defeat the immune system (BENNETT and KLICH, 2003), thereby exposing the consumer to serious health threats. In Serbia aflatoxins have been detected in high levels on the maize kernels, which are secondary metabolites produced by A. flavus and A. parasiticus (KOS et al, 2018;NIKOLIĆ et al, 2018;OBRADOVIĆ et al, 2018). Fumonisins produced mainly of F. verticillioides and F. proliferatum (Matsush.)…”

Section: Introductionmentioning

confidence: 99%

The occurrence of mycotoxins in sweet maize hybrids

et al. 2021

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The objective of the present study was to investigate the susceptibility of maize hybrids to the natural mycotoxins contamination: aflatoxin total (AFLA), deoxynivalenol (DON), zearalenon (ZEA) and fumonisins (FB). Hybrids were grown during two production years (2019 and 2020) in two locations. Mycotoxin contamination of maize grains was evaluated in five sweet maize hybrids. Contamination level of investigated hybrids of first cluster was mainly by below average values of ZEA (all equal to zero) and DON. Hybrids PK4 (S) 2020, PK6 (MS) 2020 and PK4 (MS) 2020 had below average values for AFLA, while remaining treatments of this cluster have mostly elevated values of this mycotoxin. Contamination level of investigated hybrids of second cluster mostly had increased values of mycotoxins ZEA and DON and below average values of AFLA. Samples did not contain fumonisins. Mycotoxin contamination were significantly affected by hybrids and years. We have established that DON and ZEA levels were influenced by the environmental conditions. There were no significant effects of location on the level of AFLA in the sweet maize hybrids. The variation in the properties of mycotoxin content (DON) was significantly influenced by hybrids, and there was no significance of hybrids x location interaction. Differences were more expressed for the content of ZEA and AFLA compared to the content of DON. Hybrid PK1 had the lowest content of DON, while it had the highest content of ZEA. Mycotoxin analyses showed that in all tested hybrids, levels of AFLA, DON, ZEA and FBs were below the maximum permissible levels stipulated by the legislation of the European Union and the Republic of Serbia in maize intended for direct human consumption. These results confirmed that the susceptibility of hybrids is one of the important risks, in addition to climatic factors, for the appearance of toxigenic fungi and their mycotoxins. Genotype tolerance is very important as a preventive measure, which indicates that breeders have to pay attention to it in sweet maize breeding programs.

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First Report of Aspergillus welwitschiae Causing Maize Ear Rot in Serbia

Nikolić,

Savić,

Nikolić

et al. 2024

Plant Disease

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In recent years, countries in Southeast Europe are facing climate changes characterized by extreme hot weather, which contribute to the increased frequency of Aspergillus species. Because of these changes, Aspergillus parasiticus was isolated, for the first time, from maize grain in Serbia (Nikolic et al, 2018). The presence of black powdery mycelia on maize ears indicated occurrence of species of the genus Aspergillus section Nigri, which led to the need for detailed identification of these fungi. Disease incidence ranged from 10 and 15% in August 2013. Maize ears with black powdery symptoms were collected from field in Zemun Polje, Serbia. Symptomatic kernels were surface sterilized with 1% sodium hypochlorite solution for 3 min, rinsed three times with sterilized water, then incubated at 25°C in the dark for 7 days on potato dextrose agar (PDA). Twenty isolates were identified as genus Aspergillus section Nigri. Monospore cultures formed black cottony colonies with a yellowish border on PDA. The average colony diameter was 50 mm. In order to reliably identify, isolates were transferred to Malt Extract agar (MEA) and Czapek Yeast Autolysate agar (CYA) (Samson et al, 2014). On CYA fungal colonies consisted of a white mycelium, covered by a layer of black conidiophores. On MEA fungal colonies were dense, black, with yellowish border. The reverse side was colorless to pale yellow, with a yellow ring in the middle. The average size of conidia was 4.3 µm. The conidia were globose to sub-globose, smooth to roughened, which coincides with previous research (Silva et al, 2020). Given that the fungi Aspergillus niger and Aspergillus welwitschiae are morphologically indistinguishable (Susca et al, 2016), species level identification was completed by analysis of a partial sequence of the internal transcribed spacer (ITS) region (ITS1/ITS4 primers) and calmodulin gene (CMD5/CMD6 primers) (Samson et al., 2014). The sequences were compared with the sequences of A. welwitschiae strains registered in the GenBank database based on nucleotide similarity, and results showed 99,64 and 100% similarity with ITS (OL711714) and calmodulin (KX894585), respectively. The sequence was deposited in GenBank with accession numbers OQ456471 (ITS) and OQ426518 (calmodulin). We also confirmed the presence of this species with specific primers (AWEL1/AWEL2) designed by Susca et al. 2020. Pathogenicity test was performed in Zemun Polje on the same maize hybrid from which the fungal species was isolated. Using artificial inoculations by the injecting conidial suspension into the silk channel, three days after 50% of plants reached the silking stage. Twenty ears were inoculated with each isolate, in four replicates (Reid et al, 1996). Inoculum was prepared from 7-day-old colonies on PDA, and 2 ml of a conidial suspension (1×106 spores/ml) was used. Control plants were inoculated with sterile water. All inoculated ears showed symptoms, similar to those from field infections. Control ears were symptomless. The fungus was reisolated and was morphologically identical to the original isolates, thus completing Koch’s postulates. Based on molecular, morphological and pathogenic properties, the isolates were identified as A. welwitschiae. This is the first report of A. welwitschiae as the causal agent of black maize ear rot not only in Serbia, but also in the other countries of the Western Balkans. Given that the fungus A. welwitschiae synthesizes both ochratoxin A (OTA) (Battilani et al, 2006) and fumonisin (FB) (Frisvad et al, 2011), further studies should be focused on assessment its aggressiveness and toxicological profile.

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Differentiation between Aspergillus flavus and Aspergillus parasiticus isolates originated from wheat

Cited by 5 publications

References 26 publications

Molecular Characterization of Aspergillus flavus Strains Isolated from Animal Feeds

Molecular Characterization of Aspergillus flavus Strains Isolated from Animal Feeds

The occurrence of mycotoxins in sweet maize hybrids

First Report of Aspergillus welwitschiae Causing Maize Ear Rot in Serbia

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