Transgenic expression of a gene encoding a synthetic antimicrobial peptide results in inhibition of fungal growth in vitro and in planta

The impact of five phenolic acids (ferulic, coumaric, caffeic, syringic, and p-hydroxybenzoic acids) on fungal growth and type B trichothecene production by four strains of Fusarium graminearum was investigated. All five phenolic acids inhibited growth but the degree of inhibition varied between strains. Our results suggested that the more lipophilic phenolic acids are, the higher is the effect they have on growth. Toxin accumulation in phenolic acid-supplemented liquid glucose, yeast extract, and peptone cultures was enhanced in the presence of ferulic and coumaric acids but was reduced in the presence of p-hydroxybenzoic acid. This modulation was shown to correlate with a regulation of TRI5 transcription. In this study, addition of phenolic acids with greater antioxidant properties resulted in a higher toxin accumulation, indicating that the modulation of toxin accumulation may be linked to the antioxidant properties of the phenolic acids. These data suggest that, in planta, different compositions in phenolic acids of kernels from various cultivars may reflect different degrees of sensitivity to “mycotoxinogenesis.”

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The Multifunctional β-Oxidation Enzyme Is Required for Full Symptom Development by the Biotrophic Maize Pathogen Ustilago maydis

Eukaryotic Cell ◽

10.1128/ec.00231-06 ◽

2006 ◽

Vol 5 (12) ◽

pp. 2047-2061 ◽

Cited By ~ 28

Author(s):

Jana Klose ◽

James W. Kronstad

Keyword(s):

Fatty Acids ◽

Ustilago Maydis ◽

Long Chain Fatty Acids ◽

In Planta ◽

Gene Encoding ◽

Metabolic Role ◽

Fungal Phytopathogen ◽

Long Chain ◽

Chain Fatty Acids

ABSTRACT The transition from yeast-like to filamentous growth in the biotrophic fungal phytopathogen Ustilago maydis is a crucial event for pathogenesis. Previously, we showed that fatty acids induce filamentation in U. maydis and that the resulting hyphal cells resemble the infectious filaments observed in planta. To explore the potential metabolic role of lipids in the morphological transition and in pathogenic development in host tissue, we deleted the mfe2 gene encoding the multifunctional enzyme that catalyzes the second and third reactions in β-oxidation of fatty acids in peroxisomes. The growth of the strains defective in mfe2 was attenuated on long-chain fatty acids and abolished on very-long-chain fatty acids. The mfe2 gene was not generally required for the production of filaments during mating in vitro, but loss of the gene blocked extensive proliferation of fungal filaments in planta. Consistent with this observation, mfe2 mutants exhibited significantly reduced virulence in that only 27% of infected seedlings produced tumors compared to 88% tumor production upon infection by wild-type strains. Similarly, a defect in virulence was observed in developing ears upon infection of mature maize plants. Specifically, the absence of the mfe2 gene delayed the development of teliospores within mature tumor tissue. Overall, these results indicate that the ability to utilize host lipids contributes to the pathogenic development of U. maydis.

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The Effects of Selenium on Wheat Fusarium Head Blight and DON Accumulation Were Selenium Compound-Dependent

Toxins ◽

10.3390/toxins12090573 ◽

2020 ◽

Vol 12 (9) ◽

pp. 573

Author(s):

Xueyun Mao ◽

Chen Hua ◽

Liang Yang ◽

Yuhui Zhang ◽

Zhengxi Sun ◽

...

Keyword(s):

Fusarium Head Blight ◽

Essential Element ◽

Fungal Growth ◽

Sodium Selenate ◽

In Planta ◽

Head Blight ◽

Resistant Varieties ◽

And Control ◽

Toxin Accumulation

Fusarium head blight (FHB) caused by Fusarium graminearum not only results in severe yield losses, but also contaminates wheat grains with deoxynivalenol (DON) toxins. Prevention and control of FHB and DON contamination rely mainly on resistant varieties and fungicides. Selenium (Se) is an essential element for humans and animals, and also a beneficial element for plants. In this work, four Se compounds, i.e., sodium selenite (Na2SeO3), sodium selenate (Na2SeO4), selenomethionine (SeMet) and selenocysteine (SeCys2), were supplemented in a trichothecene biosynthesis induction (TBI) solid medium at different dosages in in vitro experiments. The four Se compounds at the dosage of 20 mg∙L−1 were sprayed onto wheat spikes immediately after inoculation at anthesis. All four of the Se compounds significantly inhibited the mycelial growth and DON production in the in vitro experiment; however, in planta, their effects on FHB severity and toxin accumulation in grains were compound-dependent. SeMet consistently negatively regulated fungal growth and DON accumulation both in vitro and in planta, which could be a novel and proconsumer strategy for reducing the detriment of wheat FHB disease and DON accumulation.

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Endopolygalacturonase Genes from Colletotrichum lindemuthianum: Cloning of CLPG2 and Comparison of Its Expression to That of CLPG1 During Saprophytic and Parasitic Growth of the Fungus

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.1997.10.6.769 ◽

1997 ◽

Vol 10 (6) ◽

pp. 769-775 ◽

Cited By ~ 47

Author(s):

Sylvie Centis ◽

Isabelle Guillas ◽

Nathalie Séjalon ◽

Marie-Thérèse Esquerré-Tugayé ◽

Bernard Dumas

Keyword(s):

Synthetic Medium ◽

Amino Acid Level ◽

Single Copy ◽

Colletotrichum Lindemuthianum ◽

In Planta ◽

Gene Encoding ◽

Host Cell Wall ◽

Extensive Degradation ◽

Necrotrophic Stage

Following the previous isolation of CLPG1, a gene encoding an endopolygalacturonase (endoPG) secreted into the culture filtrate of Colletotrichum lindemuthianum, we have isolated and sequenced an additional endoPG gene, CLPG2. This gene is present as a single copy in the genome of the fungus. At the amino acid level, CLPG2 shows 61% identity to CLPG1 and between 37 to 59% identity to other fungal endoPGs. RNA blot analyses of endoPG gene expression were followed with specific probes during in vitro culture of the fungus. When conidia were used to inoculate a synthetic medium containing pectin as sole carbon source, only CLPG1 was found to be expressed after 3 days of culture. However, transferring the mycelium grown on glucose for 4 days to a pectin-containing medium allowed the detection of CLPG1 and CLPG2 transcripts as early as 12 h after transfer on this substrate. Expression of CLPG2 was transient while that of CLPG1 was more prolonged. Immunocytological localization of endoPG in C. lindemuthianum-infected bean tissues with antibodies against CLPG1 confirmed that the protein is produced in planta and is associated with extensive degradation of the host cell wall. Detection of endoPG transcripts by reverse transcription-polymerase chain reaction revealed that CLPG1, but not CLPG2, is expressed at the beginning of the necrotrophic stage of infection. These results show that the two endoPG genes are differentially expressed and that CLPG1 encodes the major secreted endoPG both during saprophytic growth and during plant infection.

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Inhibition of fungal growth in planta and in vitro by transgenic tobacco expressing a bacterial nonheme chloroperoxidase gene

Plant Cell Reports ◽

10.1007/s002990050736 ◽

2000 ◽

Vol 19 (4) ◽

pp. 333-338 ◽

Cited By ~ 25

Author(s):

K. Rajasekaran ◽

J. W. Cary ◽

K. D. Stromberg ◽

T.E. Cleveland ◽

T.J. Jacks

Keyword(s):

Transgenic Tobacco ◽

Fungal Growth ◽

In Planta

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δ-Aminolaevulinic acid synthesis is required for virulence of the wheat pathogen Stagonospora nodorum

Microbiology ◽

10.1099/mic.0.28556-0 ◽

2006 ◽

Vol 152 (5) ◽

pp. 1533-1538 ◽

Cited By ~ 9

Author(s):

Peter S. Solomon ◽

Cordula I. Jörgens ◽

Richard P. Oliver

Keyword(s):

Single Gene ◽

Acid Synthesis ◽

Gene Replacement ◽

Stagonospora Nodorum ◽

Homologous Gene ◽

In Planta ◽

Gene Encoding ◽

Aminolaevulinic Acid ◽

Key Enzyme

δ-Aminolaevulinic acid (ALA) is synthesized in fungi by ALA synthase, a key enzyme in the synthesis of haem. The requirement for ALA synthase in Stagonospora nodorum to cause disease in wheat was investigated. The single gene encoding ALA synthase (Als1) was cloned and characterized. Expression analysis determined that Als1 transcription was up-regulated during germination and also towards the latter stages of the infection. The Als1 gene was further characterized by homologous gene replacement. The inactivation of Als1 resulted in strains producing severely stunted germ tubes leading quickly to death. The strains could be recovered by supplementation with 33 μM ALA. Pathogenicity assays revealed the als1 strains were essentially non-pathogenic, inferring a key role for the synthesis of ALA during in planta growth. Supplementing the strains with ALA restored growth in vitro and also pathogenicity for up to 5 days after inoculation. Further examination by inoculating the als1 strains onto wounded leaves found that pathogenicity was only partially restored, suggesting that host-derived in planta levels of ALA are not sufficient to support growth. This study has identified a key role for fungal ALA synthesis during infection and revealed its potential as an antifungal target.

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Saccharin Provides Protection and Activates Defense Mechanisms in Wheat Against the Hemibiotrophic Pathogen Zymoseptoria tritici

Plant Disease ◽

10.1094/pdis-05-20-1106-re ◽

2020 ◽

Author(s):

Samara Mejr ◽

Maryline Magnin-Robert ◽

Beatrice Randoux ◽

Alina Ghinet ◽

Patrice Halama ◽

...

Keyword(s):

Defense Mechanisms ◽

Foliar Application ◽

Crop Protection ◽

Hyphal Growth ◽

In Planta ◽

Zymoseptoria Tritici ◽

Gene Encoding ◽

Challenge Inoculation ◽

Pathogenesis Related Protein

Plant resistance inducers are among the most promising alternatives to develop sustainable crop protection. Here, we examined the ability of saccharin, a metabolite derived from probenazole, to protect wheat against Zymoseptoria tritici, the most frequently occurring and damaging foliar pathogen on this crop. The experiments were performed in the greenhouse by treating seedlings of the wheat cv. Alixan with 15 mM saccharin two days before challenge inoculation with the Z. tritici pathogenic strain T02596. Foliar application of saccharin resulted in 77 % disease severity reduction when compared to non-treated control plants. In vitro and in planta assays showed that saccharin did not exhibit any direct antifungal effect, neither on spore germination, nor on hyphal growth. Molecular investigations from 2 to 7 days post-treatment (dpt) revealed that saccharin treatment up-regulates the expression of genes encoding for lipoxygenase (LOX) at all sampled time-points and pathogenesis-related protein 1 (PR1) at 7 dpt, in both non-infectious and infectious contexts, as well as peroxidase (POX2) in non-infectious conditions. However, saccharin did not induce significant change in the expression of PAL gene encoding for phenylalanine ammonia-lyase. Our findings report for the first time the potential of saccharin to confer protection in wheat against Z. tritici through an elicitation and priming of LOX and PR gene-related defense pathways. Further investigations would provide a better deciphering of defense mechanisms activated by this molecule in wheat against Z. tritici.

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Phytoalexin Accumulation in the Interaction Between Rice and the Blast Fungus

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-23-8-1000 ◽

2010 ◽

Vol 23 (8) ◽

pp. 1000-1011 ◽

Cited By ~ 104

Author(s):

Morifumi Hasegawa ◽

Ichiro Mitsuhara ◽

Shigemi Seo ◽

Takuya Imai ◽

Jinichiro Koga ◽

...

Keyword(s):

Host Plant ◽

Fungal Growth ◽

Hypersensitive Reaction ◽

In Planta ◽

Severe Restriction ◽

Biosynthetic Genes ◽

Blast Fungus ◽

Momilactone A ◽

Infection Stage

Blast fungus–induced accumulations of major rice diterpene phytoalexins (PA), momilactones A and B, and phytocassanes A through E were studied, focusing on their biosynthesis and detoxification. In resistant rice, all PA started to accumulate at 2 days postinoculation (dpi), at which hypersensitive reaction (HR)-specific small lesions became visible and increased 500- to 1,000-fold at 4 dpi, while the accumulation was delayed and several times lower in susceptible rice. Expression of PA biosynthetic genes was transiently induced at 2 dpi only in resistant plants, while it was highly induced in both plants at 4 dpi. Fungal growth was severely suppressed in resistant plants by 2 dpi but considerably increased at 3 to 4 dpi in susceptible plants. Momilactone A treatment suppressed fungal growth in planta and in vitro, and the fungus detoxified the PA in vitro. These results indicate that HR-associated rapid PA biosynthesis induces severe restriction of fungus, allowing higher PA accumulation in resistant rice, while in susceptible rice, failure of PA accumulation at the early infection stage allows fungal growth. Detoxification of PA would be a tactic of fungus to invade the host plant, and prompt induction of PA biosynthesis upon HR would be a trait of resistant rice to restrict blast fungus.

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A Gene Encoding a Protein Elicitor of Phytophthora infestans Is Down-Regulated During Infection of Potato

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.1997.10.1.13 ◽

1997 ◽

Vol 10 (1) ◽

pp. 13-20 ◽

Cited By ~ 165

Author(s):

Sophien Kamoun ◽

Pieter van West ◽

Anke J. de Jong ◽

Koen E. de Groot ◽

Vivianne G. A. A. Vleeshouwers ◽

...

Keyword(s):

Phytophthora Infestans ◽

Culture Media ◽

Solanum Species ◽

In Planta ◽

Gene Encoding ◽

Protein Elicitor ◽

Solanaceous Plants ◽

Solanaceae Family

Most species of the genus Phytophthora produce 10-kDa extracellular protein elicitors, collectively termed elicitins. Elicitins induce hypersensitive response in a restricted number of plants, particularly in the genus Nicotiana within the Solanaceae family. A cDNA encoding INF1, the major secreted elicitin of Phytophthora infestans, a pathogen of solanaceous plants, was isolated and characterized. The expression of the corresponding inf1 gene during the disease cycle of P. infestans was analyzed. inf1 was shown to be expressed in mycelium grown in various culture media, whereas it was not expressed in sporangiospores, zoospores, cysts, and germinating cysts. In planta, during infection of potato, particularly during the biotrophic stage, expression of inf1 was down-regulated compared to in vitro. The highest levels of expression of inf1 were observed in in vitro grown mycelium and in late stages of infection when profuse sporulation and leaf necrosis occur. The potential role of INF1 as an elicitor in interactions between P. infestans and Solanum species was investigated. Nineteen lines, representing nine solanaceous species with various levels of resistance to P. infestans, were tested for response to an Escherichia coli expressed INF1. Within the genus Solanum, resistance to P. infestans did not appear to be mediated by a defense response elicited by INF1. However, INF1 recognition could be a component of nonhost resistance of tobacco to P. infestans.

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