The influence of ecophysiological factors on growth, aflR gene expression and aflatoxin B1 production by a type strain of Aspergillus flavus

Bernáldez, Victoria; Córdoba, Juan J.; Magan, Naresh; Peromingo, Belén; Rodríguez, Alicia

doi:10.1016/j.lwt.2017.05.030

Cited by 44 publications

(36 citation statements)

References 39 publications

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“…Further, Gallo et al [ 84 ] reported high expression of the aflR and aflS regulatory genes under conditions non-conducive for aflatoxin production. Likewise, in a more recent study, Bernáldez et al [ 85 ] found a weak correlation between the expression level of aflR and aflatoxin production. The authors demonstrated that aflR expression is not a good indicator for aflatoxin production in A. flavus .…”

Section: Factors Affecting Fungal Growth and Mycotoxin Production In mentioning

confidence: 90%

Influence of Temperature and Water Activity on Deleterious Fungi and Mycotoxin Production during Grain Storage

2017

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Cereal grains are the most important food source for humans. As the global population continues to grow exponentially, the need for the enhanced yield and minimal loss of agricultural crops, mainly cereal grains, is increasing. In general, harvested grains are stored for specific time periods to guarantee their continuous supply throughout the year. During storage, economic losses due to reduction in quality and quantity of grains can become very significant. Grain loss is usually the result of its deterioration due to fungal contamination that can occur from preharvest to postharvest stages. The deleterious fungi can be classified based on predominance at different stages of crop growth and harvest that are affected by environmental factors such as water activity (aw) and eco-physiological requirements. These fungi include species such as those belonging to the genera Aspergillus and Penicillium that can produce mycotoxins harmful to animals and humans. The grain type and condition, environment, and biological factors can also influence the occurrence and predominance of mycotoxigenic fungi in stored grains. The main environmental factors influencing grain fungi and mycotoxins are temperature and aw. This review discusses the effects of temperature and aw on fungal growth and mycotoxin production in stored grains. The focus is on the occurrence and optimum and minimum growth requirements for grain fungi and mycotoxin production. The environmental influence on aflatoxin production and hypothesized mechanisms of its molecular suppression in response to environmental changes are also discussed. In addition, the use of controlled or modified atmosphere as an environmentally safe alternative to harmful agricultural chemicals is discussed and recommended future research issues are highlighted.

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Section: Factors Affecting Fungal Growth and Mycotoxin Production In mentioning

confidence: 90%

Influence of Temperature and Water Activity on Deleterious Fungi and Mycotoxin Production during Grain Storage

2017

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“…Aspergillus flavus , for example, is associated with Aspergillus infections of grain crops in the field; it also contaminates stored grains when prevailing abiotic factors (such as temperature and water activity) are favourable [ 3 , 4 ]. Interactions between environmental stress factors, such as water activity and temperature, may have an influence on growth, expression of biosynthetic regulatory genes and mycotoxin production by mycotoxigenic fungal species [ 5 , 6 ]. Good postharvest practices avoiding high temperatures and rapid drying of grain can avoid a decrease in the grain quality and reduce the health risk due to mould growth and potential toxin contamination [ 6 ].…”

Section: Introductionmentioning

confidence: 99%

“…Interactions between environmental stress factors, such as water activity and temperature, may have an influence on growth, expression of biosynthetic regulatory genes and mycotoxin production by mycotoxigenic fungal species [ 5 , 6 ]. Good postharvest practices avoiding high temperatures and rapid drying of grain can avoid a decrease in the grain quality and reduce the health risk due to mould growth and potential toxin contamination [ 6 ]. Poor postharvest management can lead to rapid deterioration in quality, with severe decreases in germinability and nutritional value of stored grain, possibly accompanied by undesirable fungal contamination and, consequently, toxin production [ 7 ].…”

Section: Introductionmentioning

confidence: 99%

Rapid Detection and Identification of Mycotoxigenic Fungi and Mycotoxins in Stored Wheat Grain

Sudharsan

Britzi²,

Zakin

et al. 2017

Toxins

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This study aimed to assess the occurrence of toxigenic fungi and mycotoxin contamination in stored wheat grains by using advanced molecular and analytical techniques. A multiplex polymerase chain reaction (PCR) strategy was established for rapid identification of mycotoxigenic fungi, and an improved analytical method was developed for simultaneous multi-mycotoxin determination in wheat grains by liquid chromatography-tandem mass spectrometry (LC/MS/MS) without the need for any clean-up. The optimized multiplex PCR method was highly specific in detecting fungal species containing species-specific and mycotoxin metabolic pathway genes. The method was applied for evaluation of 34 wheat grain samples collected from storage warehouses for the presence of mycotoxin-producing fungi, and a few samples were found positive for Fusarium and Aspergillus species. Further chemical analysis revealed that 17 samples contained mycotoxins above the level of detection, but only six samples were found to be contaminated over the EU regulatory limits with at least one mycotoxin. Aflatoxin B1, fumonisins, and deoxynivalenol were the most common toxins found in these samples. The results showed a strong correlation between the presence of mycotoxin biosynthesis genes as analyzed by multiplex PCR and mycotoxin detection by LC/MS/MS. The present findings indicate that a combined approach might provide rapid, accurate, and sensitive detection of mycotoxigenic species and mycotoxins in wheat grains.

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“…The mycelia were removed from half the surface of the dry-cured ham cubes and frozen quickly in liquid nitrogen, it was stored at −80 • C until the extraction of RNA. RNA was extracted using the commercial kit RNeasy ® plant mini kit (QIAGEN, Madrid, Spain) [52]. For this, the mycelia were mixed with 500 µL of lysis solution buffer containing 10 µL of β-mercaptoethanol and then processed according to the manufacturer's instructions.…”

Section: Rna Extractionmentioning

confidence: 99%

“…Two primers (Table 4) were used to amplify the β-tubulin gene, which was used as an endogenous control [52]. For the relative expression of the genes otapksPN and otanpsPN involved in the biosynthesis of OTA, two pairs of primers were used [19,52].…”

Section: Primers Usedmentioning

confidence: 99%

Efficacy of the Combined Protective Cultures of Penicillium chrysogenum and Debaryomyces hansenii for the Control of Ochratoxin A Hazard in Dry-Cured Ham

Cebrián

Rodrı́guez

Peromingo

et al. 2019

Toxins

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The ecological conditions during the ripening of dry-cured ham favour the development of moulds on its surface, being frequently the presence of Penicillium nordicum, a producer of ochratoxin A (OTA). Biocontrol using moulds and yeasts usually found in dry-cured ham is a promising strategy to minimize this hazard. The aim of this work is to evaluate the effect of previously selected Debaryomyces hansenii and Penicillium chrysogenum strains on growth, OTA production, and relative expression of genes involved in the OTA biosynthesis by P. nordicum. P. nordicum was inoculated against the protective cultures individually and combined on dry-cured ham for 21 days at 20 °C. None of the treatments reduced the growth of P. nordicum, but all of them decreased OTA concentration. The lower production of OTA could be related to significant repression of the relative expression of otapksPN and otanpsPN genes of P. nordicum. The efficacy of the combined protective cultures was tested in 24 dry-cured hams in industrial ripening (an 8 month-long production). OTA was detected in nine of the 12 dry-cured hams in the batch inoculated only with P. nordicum. However, in the batch inoculated with both P. nordicum and the combined protective culture, a considerable reduction of OTA contamination was observed. In conclusion, although the efficacy of individual use P. chrysogenum is great, the combination with D. hansenii enhances its antifungal activity and could be proposed as a mixed protective culture to control the hazard of the presence of OTA in dry-cured ham.

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The influence of ecophysiological factors on growth, aflR gene expression and aflatoxin B1 production by a type strain of Aspergillus flavus

Cited by 44 publications

References 39 publications

Influence of Temperature and Water Activity on Deleterious Fungi and Mycotoxin Production during Grain Storage

Influence of Temperature and Water Activity on Deleterious Fungi and Mycotoxin Production during Grain Storage

Rapid Detection and Identification of Mycotoxigenic Fungi and Mycotoxins in Stored Wheat Grain

Efficacy of the Combined Protective Cultures of Penicillium chrysogenum and Debaryomyces hansenii for the Control of Ochratoxin A Hazard in Dry-Cured Ham

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