Expression in Cereal Plants of Genes That Inactivate<i>Fusarium</i>Mycotoxins

Higa, Arisa; Kimura, Makoto; Mimori, Kouhei; Ochiai-Fukuda, Tetsuko; Tokai, Takeshi; Takahashi-Ando, Naoko; Nishiuchi, Takumi; Igawa, Tomoko; Fujimura, Masatake; Hamamoto, Hiroshi; Usami, Ron; Yamaguchi, Isamu

doi:10.1271/bbb.67.914

Cited by 25 publications

(17 citation statements)

References 14 publications

(12 reference statements)

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“…The zes2 mutants described here and known non-zearalenone-producing mutants of F. graminearum (11,22) should facilitate these studies. The results will be relevant for the assessment of the ecological impact of a large-scale release of genetically modified crops expressing zearalenone lactonase (17,18).…”

Section: Discussionmentioning

confidence: 99%

Role of Zearalenone Lactonase in Protection of Gliocladium roseum from Fungitoxic Effects of the Mycotoxin Zearalenone

Utermark

Karlovský

2007

Appl Environ Microbiol

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Zearalenone is a mycotoxin with estrogenic effects on mammals that is produced by several species of Fusarium. We found that zearalenone and its derivatives inhibit the growth of filamentous fungi on solid media at concentrations of <10 g/ml. The fungitoxic effect declined in the order zearalenone > ␣-zearalenol > ␤-zearalenol. The mycoparasitic fungus Gliocladium roseum produces a zearalenone-specific lactonase which catalyzes the hydrolysis of zearalenone, followed by a spontaneous decarboxylation. The growth of G. roseum was not inhibited by zearalenone, and the lactonase may protect G. roseum from the toxic effects of this mycotoxin. We inactivated zes2, the gene encoding zearalenone lactonase in G. roseum, by inserting a hygromycin resistance cassette into the coding sequence of the gene by means of Agrobacterium tumefaciens-mediated genetic transformation. The zes2 disruption mutants could not hydrolyze the lactone bond of zearalenone and were more sensitive to zearalenone. These data are consistent with a hypothesis that resorcylic acid lactones exemplified by zearalenone act to reduce growth competition by preventing competing fungi from colonizing substrates occupied by zearalenone producers and suggest that they may play a role in fungal defense against mycoparasites.Zearalenone [6-(10-hydroxy-6-oxo-trans-1-undecenyil)-resorcylic acid lactone] is a mycotoxin produced by several species of Fusarium, most notably Fusarium graminearum and Fusarium culmorum. Zearalenone and its derivatives exert estrogenic and anabolic effects on mammals. Carryover of zearalenone from infected grain to feedstuff causes reproductive problems in pigs, sheep, and other farm animals, including precocious sexual development, vulva enlargement, pseudopregnancy, loss of embryos, and reduced litter size (10,14,24). When digested with grain-based food, zearalenone may cause hyperestrogenism in children (33). Apart from its estrogenicity, zearalenone is genotoxic in mice and is a suspected carcinogen (5, 15, 30). The intake of zearalenone by some human populations is close to the estimated tolerable limits (9), and the amount of zearalenone allowed in grain, feedstuff, and food is regulated in several countries (1). Current ecological and economic constraints on grain production encourage minimum tillage practices and reduced fungicide application, so infection of cereal plants with Fusarium spp. is increasing and contamination with mycotoxins is becoming a more serious threat to grain production.One promising strategy for reducing zearalenone contamination is enzymatic degradation. The only commercial product on the market claimed to enzymatically detoxify zearalenone is the feed additive Mycofix Plus (Biomin GmbH, Herzogenburg, Austria). There are no published laboratory data demonstrating the hydrolysis of zearalenone by Mycofix Plus or by its active component, and such activity was not detected by us (21). The recently discovered yeast species Trichosporon mycotoxinivorans (27) degrades zearalenone and is expected to provide fut...

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Section: Discussionmentioning

confidence: 99%

Role of Zearalenone Lactonase in Protection of Gliocladium roseum from Fungitoxic Effects of the Mycotoxin Zearalenone

Utermark

Karlovský

2007

Appl Environ Microbiol

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“…For example, transformation of sugarcane with a gene encoding detoxification of the toxin albicidin provided protection against infection by Xanthomonas albilineans, the causal agent of leaf scald on susceptible sugarcane (48). Also, the Tri101 gene from Fusarium graminearum, which is responsible for self-protection of this fungus from their trichothecene toxins, provided protection against the trichothecene 4,15-diacetoxyscirpenol in transgenic tobacco (22).…”

Section: Discussionmentioning

confidence: 99%

An Oxidoreductase Is Involved in Cercosporin Degradation by the Bacterium Xanthomonas campestris pv. zinniae

Taylor¹,

Mitchell²,

Daub

2006

Appl Environ Microbiol

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The polyketide toxin cercosporin plays a key role in pathogenesis by fungal species of the genus Cercospora. The bacterium Xanthomonas campestris pv. zinniae is able to rapidly degrade this toxin. Growth of X. campestris pv. zinniae strains in cercosporin-containing medium leads to the breakdown of cercosporin and to the formation of xanosporic acid, a nontoxic breakdown product. Five non-cercosporin-degrading mutants of a strain that rapidly degrades cercosporin (XCZ-3) were generated by ethyl methanesulfonate mutagenesis and were then transformed with a genomic library from the wild-type strain. All five mutants were complemented with the same genomic clone, which encoded a putative transcriptional regulator and an oxidoreductase. Simultaneous expression of these two genes was necessary to complement the mutant phenotype. Sequence analysis of the mutants showed that all five mutants had point mutations in the oxidoreductase gene and no mutations in the regulator. Quantitative reverse transcription-PCR (RT-PCR) showed that the expression of both of these genes in the wild-type strain is upregulated after exposure to cercosporin. Both the oxidoreductase and transcriptional regulator genes were transformed into three non-cercosporin-degrading bacteria to determine if they are sufficient for cercosporin degradation. Quantitative RT-PCR analysis confirmed that the oxidoreductase was expressed in all transconjugants. However, none of the transconjugants were able to degrade cercosporin, suggesting that additional factors are required for cercosporin degradation. Further study of cercosporin degradation in X. campestris pv. zinniae may allow for the engineering of Cercosporaresistant plants by using a suite of genes.

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“…Lower levels of fumonisin B 1 were observed in kernels of transgenic corn plants as compared to conventional corn plants. Recently, genes of trichothecene and zearalenone detoxifying enzymes have also been successfully expressed in rice (Higa et al, 2003).…”

Section: Genetic Engineeringmentioning

confidence: 99%

Novel strategies to control mycotoxins in feeds: A review

Varga

Töth

2005

Acta Veterinaria Hungarica

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Mycotoxin-producing fungi may contaminate agricultural products in the field (preharvest spoilage), during storage (postharvest spoilage), or during processing. Mycotoxin contamination of foods and feeds poses serious health hazard to animals and humans. For lowering mycotoxin contamination of feeds and foods, several strategies have been investigated that can be divided into biological, chemical and physical methods. This paper gives an overview of strategies which are promising with regard to lowering the mycotoxin burden of animals and humans.

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Expression in Cereal Plants of Genes That InactivateFusariumMycotoxins

Cited by 25 publications

References 14 publications

Role of Zearalenone Lactonase in Protection of Gliocladium roseum from Fungitoxic Effects of the Mycotoxin Zearalenone

Role of Zearalenone Lactonase in Protection of Gliocladium roseum from Fungitoxic Effects of the Mycotoxin Zearalenone

An Oxidoreductase Is Involved in Cercosporin Degradation by the Bacterium Xanthomonas campestris pv. zinniae

Novel strategies to control mycotoxins in feeds: A review

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