Environmental Stress on the Production of Mycotoxins

A special issue of Toxins (ISSN 2072-6651). This special issue belongs to the section "Mycotoxins".

Deadline for manuscript submissions: closed (31 January 2022) | Viewed by 23270

Special Issue Editors

Department of Food Technology, University Center Koprivnica, University North, Trg dr. Žarka Dolinara 1, 48000 Koprivnica, Croatia
Interests: microbiology and immunology; mycotoxins; lc-ms/ms; antifungal testing
Department of Applied Chemistry and Ecology, Faculty of Food Technology, Josip Juraj Strossmayer University of Osijek, 31000 Osijek, Croatia
Interests: fungi; mycotoxins; nanoparticles; food safety
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The mycotoxin produced by the secondary metabolism of agricultural and foodborne important fungi is a low molecular weight but highly toxic compound and a significant hazard for human and animal health. These compounds occur naturally in the environment, but their production is increased due to various natural and synthetic environmental stressors that can modulate the oxidative status of the fungal cell. Oxidative stress is one of the main factors that triggers mycotoxin biosynthesis in fungal cells. Furthermore, climate change is also important in those metabolic pathways since it strongly negatively regulates environmental factors such as temperature, rainfall level, and CO2 concentration and thus shapes the fungal community in the environment and mycotoxin production. A constant evaluation of mycotoxin risk is needed as insurance for a minimization of the adverse effects caused by environmental stress factors of any kind. Such processes can be evaluated on a molecular and genetic level, but with the same aim of establishing mechanisms that are able to control and reduce contamination of the environment with mycotoxins. This will not only protect human and animal health but also decrease economic losses and increase food availability, especially in developing countries.

For these reasons, this Special Issue on “Environmental Stress on the Production of Mycotoxins” shall cover all the important topics related to mycotoxin production influenced by stressors from the environment that occur naturally, are applied on purpose, are a consequence of environmental pollution and climate change and are thus becoming important stress factors that modulate fungal cell oxidative status and mycotoxin production.

Dr. Bojan Šarkanj
Dr. Tihomir Kovač
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a double-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Toxins is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • environment
  • oxidative stress
  • mycotoxins
  • climate change
  • plant resistance
  • weather conditions

Published Papers (7 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

10 pages, 985 KiB  
Article
Relationship between the Fungal Incidence, Water Activity, Humidity, and Aflatoxin Content in Maize Samples from the Highlands and Coast of Ecuador
Toxins 2022, 14(3), 196; https://doi.org/10.3390/toxins14030196 - 06 Mar 2022
Cited by 1 | Viewed by 2269
Abstract
This study evaluated the fungal incidence through direct plating in Agar Dichloran Glycerol, and the presence of aflatoxins in maize samples from the Highlands and Coast of Ecuador by HPLC, investigating the influence of the temperature, altitude, water activity, and humidity of the [...] Read more.
This study evaluated the fungal incidence through direct plating in Agar Dichloran Glycerol, and the presence of aflatoxins in maize samples from the Highlands and Coast of Ecuador by HPLC, investigating the influence of the temperature, altitude, water activity, and humidity of the collection regions on the maize samples’ contamination using Principal Components Analysis (PCA). The overall kernel infection by fungi was usually lower in samples from the Highlands, and no aflatoxins or Aspergillus series Flavi were detected in the samples from this region. In the coastal samples, Aspergillus sp. were isolated from all samples, while the potentially aflatoxigenic A. Flavi contaminated about 80% of them. Aflatoxins were present in 50% of these samples, in ranges from 0.42 to 107.69 µg/kg. PCA was able to segregate the samples according to their collection region, and showed that the maximum and minimum temperatures are closely and positively related to the presence of A. Flavi. A highly positive relationship was also observed between the water activity of the sample and aflatoxin contamination. On the other hand, the altitude had a very strong—but negative—relationship with the variables studied. This study is relevant because data regarding fungi and aflatoxin occurrence, as well the main factor influencing the contamination of Ecuadoran maize, are scarce; it clearly shows that aflatoxins are a hazard present in maize from the Ecuadorian Coast but not the Highlands. Full article
(This article belongs to the Special Issue Environmental Stress on the Production of Mycotoxins)
Show Figures

Graphical abstract

17 pages, 11262 KiB  
Article
Regulated Mycotoxin Occurrence and Co-Occurrence in Croatian Cereals
Toxins 2022, 14(2), 112; https://doi.org/10.3390/toxins14020112 - 02 Feb 2022
Cited by 7 | Viewed by 2221
Abstract
A total of 209 samples of various cereal crops (maize, wheat, barley, rye and oats) grown in Croatian fields during 2016 and 2017 were collected to analyze and determine the occurrence and co-occurrence of EU regulated mycotoxins in cereals (AFB1, AFB2, AFG1, AFG2, [...] Read more.
A total of 209 samples of various cereal crops (maize, wheat, barley, rye and oats) grown in Croatian fields during 2016 and 2017 were collected to analyze and determine the occurrence and co-occurrence of EU regulated mycotoxins in cereals (AFB1, AFB2, AFG1, AFG2, DON, FB1, FB2, ZEA, T-2, HT-2 and OTA). The analysis, performed by a validated confirmatory LC-MS/MS method based on a dilute and shoot principle, highlighted Fusarium mycotoxins as the main contaminants, often co-occurring in samples from both years (50.0% in 2016 and 33.7% in 2017). DON was found to be the most frequent mycotoxin, present in 72.5% of the 2016 samples and 32.6% of the 2017 samples, while maize proved to be the most contaminated cereal type of both years with FUM as the most abundant mycotoxins, with an average concentration of 1180 µg/kg. Moderate temperatures with periods of high humidity favored the accumulation of DON in wheat samples instead of other Fusarium mycotoxins, while similar conditions favored maize contamination with FUM. A total of 8.3% of all the 2016 harvest samples and 7.9% of the 2017 harvest samples were assessed as non-compliant, containing mycotoxins in concentrations higher than the levels set by the EU legislation for food. Full article
(This article belongs to the Special Issue Environmental Stress on the Production of Mycotoxins)
Show Figures

Figure 1

18 pages, 1674 KiB  
Article
Prevalence of Fusarium fungi and Deoxynivalenol Levels in Winter Wheat Grain in Different Climatic Regions of Poland
Toxins 2022, 14(2), 102; https://doi.org/10.3390/toxins14020102 - 28 Jan 2022
Cited by 14 | Viewed by 2381
Abstract
Fusarium head blight (FHB) caused by fungi of the genus Fusarium is one of the most dangerous crop diseases, which has a wide geographic distribution and causes severe economic losses in the production of major cereal species. The infection leads to the accumulation [...] Read more.
Fusarium head blight (FHB) caused by fungi of the genus Fusarium is one of the most dangerous crop diseases, which has a wide geographic distribution and causes severe economic losses in the production of major cereal species. The infection leads to the accumulation of mycotoxins in grains, which compromises its suitability for human and animal consumption. The study demonstrated that grain samples from warmer regions of Poland, including Sulejów and Tomaszów Bolesławicki (results differed across years of the study), were colonized mainly by F. graminearum and were most highly contaminated with deoxynivalenol (DON). Samples from Northeastern Poland, i.e., Ruska Wieś, which is located in a cooler region, were characterized by a predominance of Fusarium species typical of the cold climate, i.e., Fusarium poae and Penicillium verrucosum. A Spearman’s rank correlation analysis revealed that the severity of grain infection with F. avenaceum/F. tricinctum was affected by the mean daily temperature and high humidity in May, and the corresponding values of the correlation coefficient were determined at R = 0.54 and R = 0.50. Competitive interactions were observed between the F. avenaceum/F. tricinctum genotype and DON-producing F. culmorum and F. graminearum, because the severity of grain infections caused by these pathogens was bound by a negative correlation. Full article
(This article belongs to the Special Issue Environmental Stress on the Production of Mycotoxins)
Show Figures

Figure 1

13 pages, 3908 KiB  
Article
Penicillium expansum Impact and Patulin Accumulation on Conventional and Traditional Apple Cultivars
Toxins 2021, 13(10), 703; https://doi.org/10.3390/toxins13100703 - 04 Oct 2021
Cited by 11 | Viewed by 4971
Abstract
Penicillium expansum is a necrotrophic plant pathogen among the most ubiquitous fungi disseminated worldwide. It causes blue mould rot in apples during storage, transport and sale, threatening human health by secreting patulin, a toxic secondary metabolite that contaminates apples and apple-derived products. Nevertheless, [...] Read more.
Penicillium expansum is a necrotrophic plant pathogen among the most ubiquitous fungi disseminated worldwide. It causes blue mould rot in apples during storage, transport and sale, threatening human health by secreting patulin, a toxic secondary metabolite that contaminates apples and apple-derived products. Nevertheless, there is still a lack of sufficient data regarding the resistance of different apple cultivars to P. expansum, especially ancient ones, which showed to possess certain resistance to plant diseases. In this work, we investigated the polyphenol profile of 12 traditional and 8 conventional apple cultivar and their resistance to P. expansum CBS 325.48. Eight polyphenolic compounds were detected; the most prominent were catechin, epicatechin and gallic acid. The highest content of catechin was detected in ‘Apistar’—91.26 mg/100 g of fresh weight (FW), epicatechin in ‘Bobovac’—67.00 mg/100 g of FW, and gallic acid in ‘Bobovac’ and ‘Kraljevčica’—8.35 and 7.40 mg/100 g of FW, respectively. The highest content of patulin was detected in ‘Kraljevčica’ followed by ‘Apistar’—1687 and 1435 µg/kg, respectively. In apple cultivars ‘Brčko’, ‘Adamčica’ and ‘Idared’, patulin was not detected. Furthermore, the patulin content was positively correlated with gallic acid (r = 0.4226; p = 0.002), catechin (r = 0.3717; p = 0.008) and epicatechin (r = 0.3305; p = 0.019). This fact indicates that higher contents of gallic acid, catechin and epicatechin negatively affected and boost patulin concentration in examined apple cultivars. This can be related to the prooxidant activity of polyphenolic compounds and sensitivity of P. expansum to the disturbance of oxidative status. Full article
(This article belongs to the Special Issue Environmental Stress on the Production of Mycotoxins)
Show Figures

Figure 1

15 pages, 766 KiB  
Article
Influence of H2O2-Induced Oxidative Stress on In Vitro Growth and Moniliformin and Fumonisins Accumulation by Fusarium proliferatum and Fusarium subglutinans
Toxins 2021, 13(9), 653; https://doi.org/10.3390/toxins13090653 - 15 Sep 2021
Cited by 4 | Viewed by 2294
Abstract
Fusarium proliferatum and Fusarium subglutinans are common pathogens of maize which are known to produce mycotoxins, including moniliformin (MON) and fumonisins (FBs). Fungal secondary metabolism and response to oxidative stress are interlaced, where hydrogen peroxide (H2O2) plays a pivotal [...] Read more.
Fusarium proliferatum and Fusarium subglutinans are common pathogens of maize which are known to produce mycotoxins, including moniliformin (MON) and fumonisins (FBs). Fungal secondary metabolism and response to oxidative stress are interlaced, where hydrogen peroxide (H2O2) plays a pivotal role in the modulation of mycotoxin production. The objective of this study is to examine the effect of H2O2-induced oxidative stress on fungal growth, as well as MON and FBs production, in different isolates of these fungi. When these isolates were cultured in the presence of 1, 2, 5, and 10 mM H2O2, the fungal biomass of F. subglutinans isolates showed a strong sensitivity to increasing oxidative conditions (27–58% reduction), whereas F. proliferatum isolates were not affected or even slightly improved (45% increase). H2O2 treatment at the lower concentration of 1 mM caused an almost total disappearance of MON and a strong reduction of FBs content in the two fungal species and isolates tested. The catalase activity, surveyed due to its crucial role as an H2O2 scavenger, showed no significant changes at 1 mM H2O2 treatment, thus indicating a lack of correlation with MON and FB changes. H2O2 treatment was also able to reduce MON and FB content in certified maize material, and the same behavior was observed in the presence and absence of these fungi, highlighting a direct effect of H2O2 on the stability of these mycotoxins. Taken together, these data provide insights into the role of H2O2 which, when increased under stress conditions, could affect the vegetative response and mycotoxin production (and degradation) of these fungi. Full article
(This article belongs to the Special Issue Environmental Stress on the Production of Mycotoxins)
Show Figures

Figure 1

20 pages, 2455 KiB  
Article
Mycotoxins, Phytoestrogens and Other Secondary Metabolites in Austrian Pastures: Occurrences, Contamination Levels and Implications of Geo-Climatic Factors
Toxins 2021, 13(7), 460; https://doi.org/10.3390/toxins13070460 - 30 Jun 2021
Cited by 24 | Viewed by 4655
Abstract
Pastures are key feed sources for dairy production and can be contaminated with several secondary metabolites from fungi and plants with toxic or endocrine-disrupting activities, which possess a risk for the health, reproduction and performance of cattle. This exploratory study aimed to determine [...] Read more.
Pastures are key feed sources for dairy production and can be contaminated with several secondary metabolites from fungi and plants with toxic or endocrine-disrupting activities, which possess a risk for the health, reproduction and performance of cattle. This exploratory study aimed to determine the co-occurrences and concentrations of a wide range of mycotoxins, phytoestrogens and other secondary metabolites in grazing pastures. Representative samples of pastures were collected from 18 Austrian dairy farms (one sample per farm) between April to October 2019. After sample preparation (drying and milling) the pastures were subjected to multi-metabolite analysis using LC-MS/MS. In total, 68 metabolites were detected, including regulated zearalenone and deoxynivalenol (range: 2.16–138 and 107–505 μg/kg on a dry matter (DM) basis, respectively), modified (3-deoxynivalenol-glucoside, HT-2-glucoside) and emerging Fusarium mycotoxins (e.g., enniatins), ergot alkaloids and Alternaria metabolites along with phytoestrogens and other metabolites. Aflatoxins, fumonisins, T-2 toxin, HT-2 toxin and ochratoxins were not detected. Of the geo-climatic factors and botanical diversity investigated, the environment temperature (average of 2 pre-sampling months and the sampling month) was the most influential factor. The number of fungal metabolites linearly increased with increasing temperatures and temperatures exceeding 15 °C triggered an exponential increment in the concentrations of Fusarium and Alternaria metabolites and ergot alkaloids. In conclusion, even though the levels of regulated mycotoxins detected were below the EU guidance levels, the long-term exposure along with co-occurrence with modified and emerging mycotoxins might be an underestimated risk for grazing and forage-fed livestock. The one-year preliminary data points out a dominant effect of environmental temperature in the diversity and contamination level of fungal metabolites in pastures. Full article
(This article belongs to the Special Issue Environmental Stress on the Production of Mycotoxins)
Show Figures

Figure 1

11 pages, 2734 KiB  
Article
Effects of Light on the Ochratoxigenic Fungi Aspergillus ochraceus and A. carbonarius
Toxins 2021, 13(4), 251; https://doi.org/10.3390/toxins13040251 - 31 Mar 2021
Cited by 15 | Viewed by 3124
Abstract
Ochratoxin A (OTA) usually contaminates agricultural products such as grapes, oatmeal, coffee and spices. Light was reported as an effective strategy to control spoilage fungi and mycotoxins. This research investigated the effects of light with different wavelengths on the growth and the production [...] Read more.
Ochratoxin A (OTA) usually contaminates agricultural products such as grapes, oatmeal, coffee and spices. Light was reported as an effective strategy to control spoilage fungi and mycotoxins. This research investigated the effects of light with different wavelengths on the growth and the production of OTA in Aspergillus ochraceus and Aspergillus carbonarius. The results showed that the growth of both fungi were extremely inhibited by UV-B. Short-wavelength (blue, violet) significantly inhibited the production of OTA in both fungi, while the inhibitory effect of white was only demonstrated on A. ochraceus. These results were supported by the expression profiles of OTA biosynthetic genes of A. ochraceus and A. carbonarius. To clarify, the decrease in OTA production is induced by inhibition or degradation; therefore, the degradation of OTA under different wavelengths of light was tested. Under UV-B, the degradation rate of 10 μg/mL OTA standard pure-solution samples could reach 96.50% in 15 days, and the degradation effect of blue light was relatively weak. Furthermore, infection experiments of pears showed that the pathogenicity of both fungi was significantly decreased under UV-B radiation. Thus, these results suggested that light could be used as a potential target for strategies in the prevention and control of ochratoxigenic fungi. Full article
(This article belongs to the Special Issue Environmental Stress on the Production of Mycotoxins)
Show Figures

Figure 1

Back to TopTop