Regulation of Morphology, Aflatoxin Production, and Virulence of Aspergillus flavus by the Major Nitrogen Regulatory Gene areA

Fasoyin, Opemipo Esther; Yang, Kunlong; Qiu, Mengguang; Wang, Bin; Wang, Sen; Wang, Shihua

doi:10.3390/toxins11120718

Cited by 24 publications

(26 citation statements)

References 67 publications

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“…In A. flavus: areA was recently identified in A. flavus and demonstrated to be partially involved in aflatoxin production. The lack and overexpression of areA resulted in increased/decreased amounts of aflatoxin depending on the nitrogen source media [111]. The direct implication of AreA in aflS expression has been demonstrated in the presence of different sources of nitrate and ammonium [112].…”

Section: Demonstration Of the Connection With Af/st Synthesismentioning

confidence: 99%

Aflatoxin Biosynthesis and Genetic Regulation: A Review

Caceres

Khoury

et al. 2020

Toxins

205

177

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The study of fungal species evolved radically with the development of molecular techniques and produced new evidence to understand specific fungal mechanisms such as the production of toxic secondary metabolites. Taking advantage of these technologies to improve food safety, the molecular study of toxinogenic species can help elucidate the mechanisms underlying toxin production and enable the development of new effective strategies to control fungal toxicity. Numerous studies have been made on genes involved in aflatoxin B1 (AFB1) production, one of the most hazardous carcinogenic toxins for humans and animals. The current review presents the roles of these different genes and their possible impact on AFB1 production. We focus on the toxinogenic strains Aspergillus flavus and A. parasiticus, primary contaminants and major producers of AFB1 in crops. However, genetic reports on A. nidulans are also included because of the capacity of this fungus to produce sterigmatocystin, the penultimate stable metabolite during AFB1 production. The aim of this review is to provide a general overview of the AFB1 enzymatic biosynthesis pathway and its link with the genes belonging to the AFB1 cluster. It also aims to illustrate the role of global environmental factors on aflatoxin production and the recent data that demonstrate an interconnection between genes regulated by these environmental signals and aflatoxin biosynthetic pathway.

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Section: Demonstration Of the Connection With Af/st Synthesismentioning

confidence: 99%

Aflatoxin Biosynthesis and Genetic Regulation: A Review

Caceres

Khoury

et al. 2020

Toxins

205

177

View full text Add to dashboard Cite

show abstract

“…Similarly, if ROS is applied in vitro, aflatoxin production can be stimulated [47], such as aflatoxin biosynthesis stimulated by H 2 O 2 in A. flavus [31]. Previous studies have shown that several transcription factors have been involved in oxidative stress and secondary metabolism, including numerous bZIP-type TFs [29,48,49]. In aspergilli, Yap1 orthologs were reported as the coregulator of oxidative stress response with secondary metabolism, such as napA in A. nidulans, Aoyap1 in A. ochraceus, Apyap1 in A. parasiticus, and Afap1 in A. flavus [6,9,10,31].…”

Section: Discussionmentioning

confidence: 99%

The bZIP Transcription Factor AflRsmA Regulates Aflatoxin B1 Biosynthesis, Oxidative Stress Response and Sclerotium Formation in Aspergillus flavus

Wang

Zha

et al. 2020

Toxins

Self Cite

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Fungal secondary metabolites play important roles not only in fungal ecology but also in humans living as beneficial medicine or harmful toxins. In filamentous fungi, bZIP-type transcription factors (TFs) are associated with the proteins involved in oxidative stress response and secondary metabolism. In this study, a connection between a bZIP TF and oxidative stress induction of secondary metabolism is uncovered in an opportunistic pathogen Aspergillus flavus, which produces carcinogenic and mutagenic aflatoxins. The bZIP transcription factor AflRsmA was identified by a homology research of A. flavus genome with the bZIP protein RsmA, involved in secondary metabolites production in Aspergillus nidulans. The AflrsmA deletion strain (∆AflrsmA) displayed less sensitivity to the oxidative reagents tert-Butyl hydroperoxide (tBOOH) in comparison with wild type (WT) and AflrsmA overexpression strain (AflrsmA OE ), while AflrsmA OE strain increased sensitivity to the oxidative reagents menadione sodium bisulfite (MSB) compared to WT and ∆AflrsmA strains. Without oxidative treatment, aflatoxin B 1 (AFB 1 ) production of ∆AflrsmA strains was consistent with that of WT, but AflrsmA OE strain produced more AFB 1 than WT; tBOOH and MSB treatment decreased AFB 1 production of ∆AflrsmA compared to WT. Besides, relative to WT, ∆AflrsmA strain decreased sclerotia, while AflrsmA OE strain increased sclerotia. The decrease of AFB 1 by ∆AflrsmA but increase of AFB 1 by AflrsmA OE was on corn. Our results suggest that AFB 1 biosynthesis is regulated by AflRsmA by oxidative stress pathways and provide insights into a possible function of AflRsmA in mediating AFB 1 biosynthesis response host defense in pathogen A. flavus.Key Contribution: Without oxidative treatment, deletion of AflrsmA has no impact on aflatoxin B 1 (AFB 1 ) biosynthesis in comparison with the wild type strain. However, the AflrsmA disruptant produces less AFB 1 on corn seeds and on YGT medium containing oxidative reagent menadione sodium bisulfite or tert-Butyl hydroperoxide.Toxins 2020, 12, 271 2 of 17 basic leucine zipper (bZIP) domain. The bZIP-type transcription factor as one of the largest families of dimerizing TFs is widely distributed in the all eukaryotes genomes. The first bZIP-type TF was discovered in humans over 30 years ago [2]. Then, it was found that bZIP-type TFs are involved in metabolism, development, cell cycle, reproduction, and programmed cell death [1]. In plants, the functions of bZIP-type TFs include abiotic stress response, metabolism, mediating pathogen defense, hormone signaling, and senescence [3]. bZIP-type TFs are involved in various biological processes in fungi (described below).In Saccharomyces cerevisiae, the first bZIP-type TF called Yap (yeast activator protein) was found [4], then a subset of YAP TFs (YAP1-YAP8) have been well defined [5]. Several bZIP proteins have been reported in filamentous fungi, such as Aspergillus spp. [6-11], Neurospora crassa [12], plant pathogens Fusarium graminearum [13], Magnaporthe oryzae [14], and ...

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“…Mycotoxins like aflatoxins, trichothecenes, and structurally related toxins are major concerns in food contamination because of their high toxicity to mammals (Arunachalam and Doohan, 2013;Fasoyin et al, 2019;Luciano-Rosario et al, 2020). However, many of these fungal SM also contribute to plant colonization and pathogenicity.…”

Section: Non-traditional Effectors and Host-selective Toxins (Hsts)mentioning

confidence: 99%

Effectors of Plant Necrotrophic Fungi

et al. 2021

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Plant diseases caused by necrotrophic fungal pathogens result in large economic losses in field crop production worldwide. Effectors are important players of plant-pathogen interaction and deployed by pathogens to facilitate plant colonization and nutrient acquisition. Compared to biotrophic and hemibiotrophic fungal pathogens, effector biology is poorly understood for necrotrophic fungal pathogens. Recent bioinformatics advances have accelerated the prediction and discovery of effectors from necrotrophic fungi, and their functional context is currently being clarified. In this review we examine effectors utilized by necrotrophic fungi and hemibiotrophic fungi in the latter stages of disease development, including plant cell death manipulation. We define “effectors” as secreted proteins and other molecules that affect plant physiology in ways that contribute to disease establishment and progression. Studying and understanding the mechanisms of necrotrophic effectors is critical for identifying avenues of genetic intervention that could lead to improved resistance to these pathogens in plants.

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Regulation of Morphology, Aflatoxin Production, and Virulence of Aspergillus flavus by the Major Nitrogen Regulatory Gene areA

Cited by 24 publications

References 67 publications

Aflatoxin Biosynthesis and Genetic Regulation: A Review

Aflatoxin Biosynthesis and Genetic Regulation: A Review

The bZIP Transcription Factor AflRsmA Regulates Aflatoxin B1 Biosynthesis, Oxidative Stress Response and Sclerotium Formation in Aspergillus flavus

Effectors of Plant Necrotrophic Fungi

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