scholarly journals Ecological Basis of the Interaction betweenPseudozyma flocculosaand Powdery Mildew Fungi

2010 ◽  
Vol 77 (3) ◽  
pp. 926-933 ◽  
Author(s):  
Walid Hammami ◽  
Candy Quiroga Castro ◽  
Wilfried Rémus-Borel ◽  
Caroline Labbé ◽  
Richard R. Bélanger
Keyword(s):  
Powdery Mildew ◽  
Fluorescent Protein ◽  
Close Relative ◽  
Tomato Plants ◽  
Powdery Mildews ◽  
Biocontrol Activity ◽  
Cellobiose Lipids ◽  
Powdery Mildew Fungi ◽  
Green Fluorescent ◽  
Ecological Basis

ABSTRACTIn this work, we sought to understand how glycolipid production and the availability of nutrients could explain the ecology ofPseudozyma flocculosaand its biocontrol activity. For this purpose, we compared the development ofP. flocculosato that of a close relative, the plant pathogenUstilago maydis, under different environmental conditions. This approach was further supported by measuring the expression ofcyp1, a pivotal gene in the synthesis of unique antifungal cellobiose lipids of both fungi. On healthy cucumber and tomato plants, the expression ofcyp1remained unchanged over time inP. flocculosaand was undetected inU. maydis. At the same time, green fluorescent protein (GFP) strains of both fungi showed only limited green fluorescence on control leaves. On powdery mildew-infected cucumber leaves,P. flocculosainduced a complete collapse of the pathogen colonies, but glycolipid production, as studied bycyp1expression, was still comparable to that of controls. In complete contrast,cyp1was upregulated nine times whenP. flocculosawas applied toBotrytis cinerea-infected leaves, but the biocontrol fungus did not develop very well on the pathogen. Analysis of the possible nutrients that could stimulate the growth ofP. flocculosaon powdery mildew structures revealed that the complex Zn/Mn played a key role in the interaction. Other related fungi such asU. maydisdo not appear to have the same nutritional requirements and hence lack the ability to colonize powdery mildews. Whether production of antifungal glycolipids contributes to the release of nutrients from powdery mildew colonies is unclear, but the specificity of the biocontrol activity ofP. flocculosatoward Erysiphales does appear to be more complex than simple antibiosis.

scholarly journals Green Fluorescent Protein Transformation Sheds More Light on a Widespread Mycoparasitic Interaction

2019 ◽  
Vol 109 (8) ◽  
pp. 1404-1416
Author(s):  
Márk Z. Németh ◽  
Alexandra Pintye ◽  
Áron N. Horváth ◽  
Pál Vági ◽  
Gábor M. Kovács ◽  
...  
Keyword(s):  
Green Fluorescent Protein ◽  
Powdery Mildew ◽  
Plant Pathogens ◽  
Fluorescent Protein ◽  
Environmental Fate ◽  
Molecular Genetic ◽  
Powdery Mildews ◽  
Before And After ◽  
Mycoparasitic Fungi ◽  
Green Fluorescent

Powdery mildews, ubiquitous obligate biotrophic plant pathogens, are often attacked in the field by mycoparasitic fungi belonging to the genus Ampelomyces. Some Ampelomyces strains are commercialized biocontrol agents of crop pathogenic powdery mildews. Using Agrobacterium tumefaciens-mediated transformation (ATMT), we produced stable Ampelomyces transformants that constitutively expressed green fluorescent protein (GFP) to (i) improve the visualization of the mildew–Ampelomyces interaction and (ii) decipher the environmental fate of Ampelomyces fungi before and after acting as a mycoparasite. Detection of Ampelomyces structures, and especially hyphae, was greatly enhanced when diverse powdery mildew, leaf, and soil samples containing GFP transformants were examined with fluorescence microscopy compared with brightfield and differential interference contrast optics. We showed for the first time, to our knowledge, that Ampelomyces strains can persist up to 21 days on mildew-free host plant surfaces, where they can attack powdery mildew structures as soon as these appear after this period. As saprobes in decomposing, powdery mildew-infected leaves on the ground and also in autoclaved soil, Ampelomyces strains developed new hyphae but did not sporulate. These results indicate that Ampelomyces strains occupy a niche in the phyllosphere where they act primarily as mycoparasites of powdery mildews. Our work has established a framework for a molecular genetic toolbox for the genus Ampelomyces using ATMT.

scholarly journals First records of powdery mildew fungi (Erysiphales) on four medicinal plants in Taiwan

2020 ◽  
Author(s):  
Yu-Wei Yeh ◽  
Pei-Yi Chou ◽  
Hsin-Yu Hou ◽  
Roland Kirschner
Keyword(s):  
Powdery Mildew ◽  
Medicinal Plants ◽  
Species Identification ◽  
Host Plants ◽  
New Records ◽  
Its Sequences ◽  
New Host ◽  
Powdery Mildews ◽  
Eryngium Foetidum ◽  
Powdery Mildew Fungi

Abstract Background Production of medicinal plants in Taiwan is not only hampered by international market competition, but also lack of knowledge of their pathogens, such as powdery mildew fungi (Erysiphales, Ascomycota). Records of these fungi in Taiwan originate from few researchers for the last one hundred years and are still incomplete. Since powdery mildews in tropical/subtropical environments do not develop the sexual stages with morphologically diagnostic characteristics, internal transcribed spacer sequences (ITS) of the ribosomal RNA genes obtained from the asexual stages have become important modern tools for species identification. Results Powdery mildews on four medicinal plants from educational and ornamental plantations in Taiwan were identified based on the anamorph morphology and ITS sequences. Three powdery mildews on medicinal plants are new records for Taiwan, Arthrocladiella mougeotii on Lycium chinense, Erysiphe lespedezae on Uraria crinita, and E. lonicerae on Lonicera japonica. Eryngium foetidum is a new host for Erysiphe heraclei hitherto known on other host plants in Taiwan. Eryngium foetidum and Uraria crinita are new host plants for powdery mildews worldwide. Only specific field collection of the pathogens yielded the new records, not checking plant specimens in a phanerogam herbarium. The pathogens did not cause death of the host plants, but appeared to enhance stress by infection of mature leaves. Conclusions Taxonomic study of powdery mildews in Taiwan results into new host records of economically important medicinal plants in Taiwan with potential consequences for plant production and quarantine and also shows that host records are quite incomplete worldwide. Although ITS sequences were useful for species identification, the lack of data for several species on the same host genus on the one hand and the low variation between closely related species on the other indicate the need for further study.

scholarly journals Characterization of Powdery Mildew Caused by Leveillula taurica on Calla Lily in California

Plant Disease ◽  
2002 ◽  
Vol 86 (2) ◽  
pp. 187-187 ◽  
Author(s):  
S. T. Koike ◽  
P. Beckman
Keyword(s):  
Powdery Mildew ◽  
Cross Sections ◽  
Late Summer ◽  
Tomato Plants ◽  
Leveillula Taurica ◽  
Calla Lily ◽  
Initial Symptoms ◽  
Humidity Chamber ◽  
Advanced Stages ◽  
Powdery Mildew Fungi

Spring calla lily (Zantedeschia spp.), also known as colored or miniature calla, has markedly increased in popularity in recent years, and the production acreage in the central coast counties of California (Monterey, Santa Cruz, and San Benito), therefore, has significantly increased. Commercial plantings of calla lily (Z. albo maculata and Z. rehmannii hybrids) in California have been infected with a powdery mildew for several years, with the disease particularly evident in late summer and fall. In 2001, powdery mildew was again prevalent, and the pathogen was examined in detail. Initial symptoms consisted of chlorotic, circular-to-oval leaf lesions with diffuse margins. As the disease progressed, white sporulation became visible on lesions. In advanced stages of the disease, the center tissue of lesions turned necrotic. For any such lesion, both the corresponding adaxial and abaxial sides of the leaf always exhibited the symptoms of the disease and developed sporulation of the pathogen. Epidermal strips from both sides of leaves and leaf cross sections were mounted in drops of lactophenol and aniline blue and examined with a light microscope. These preparations showed that epiphytic mycelium was absent and all conidiophores developed from endophytic mycelium and emerged through stomata. Conidiophores carried single or sometimes two conidia and were sometimes branched. Hyaline, single-celled conidia were dimorphic. Primary (terminal) conidia were lanceolate with distinct apical points and measured (58-) 67 to 78 (-81) × 14 to 22 μm. Secondary conidia were ellipsoid-cylindric and measured (56-) 58 to 72 × 17 to 22 μm. For both conidial types, length to width ratios were greater than three. Based on these characters, the pathogen was identified as Leveillula taurica (anamorph Oidiopsis taurica). Cleistothecia were not observed. To test whether the calla lily pathogen could infect another known host of L. taurica, diseased calla lily leaves were gently pressed against leaves of potted tomato (Lycopersicon esculentum) plants (2). Inoculated tomato plants were kept in a humidity chamber for 48 h and maintained in a greenhouse (24 to 26°C). After 12 days, chlorotic lesions appeared on inoculated tomato leaves, and sporulation of L. taurica was observed on the lesions. Uninoculated control tomato plants did not develop powdery mildew. To our knowledge, this is the first report of powdery mildew, caused by L. taurica, on calla lily in North America. This disease has been reported on calla lily in South Africa, Spain, Taiwan, Turkey, and Zimbabwe (1,3,4). References: (1) Y.-K. Chen et al. Ann. Phytopathol. Soc. Jpn. 62:580, 1996. (2) J. C. Correll et al. Plant Dis. 71:248, 1987. (3) K. A. Hirata. Host Range and Geographic Distribution of the Powdery Mildew Fungi. Japan Scientific Society Press, Tokyo, 1986. (4) E. Sezgin et al. J. Turkish Phytopathol. 13:111, 1984.

scholarly journals Induction and Suppression of PEN3 Focal Accumulation During Pseudomonas syringae pv. tomato DC3000 Infection of Arabidopsis

2013 ◽  
Vol 26 (8) ◽  
pp. 861-867 ◽  
Author(s):  
Xiu-Fang Xin ◽  
Kinya Nomura ◽  
William Underwood ◽  
Sheng Yang He
Keyword(s):  
Pseudomonas Syringae ◽  
Type Iii Secretion ◽  
Cellular Response ◽  
Fluorescent Protein ◽  
Bacterial Pathogen ◽  
Tomato Dc3000 ◽  
Positive Role ◽  
Powdery Mildew Fungi ◽  
Combined Action ◽  
Green Fluorescent

The pleiotropic drug resistance (PDR) proteins belong to the super-family of ATP-binding cassette (ABC) transporters. AtPDR8, also called PEN3, is required for penetration resistance of Arabidopsis to nonadapted powdery mildew fungi. During fungal infection, plasma-membrane-localized PEN3 is concentrated at fungal entry sites, as part of the plant's focal immune response. Here, we show that the pen3 mutant is compromised in resistance to the bacterial pathogen Pseudomonas syringae pv. tomato DC3000. P. syringae pv. tomato DC3000 infection or treatment with a flagellin-derived peptide, flg22, induced strong focal accumulation of PEN3-green fluorescent protein. Interestingly, after an initial induction of PEN3 accumulation, P. syringae pv. tomato DC3000 but not the type-III-secretion-deficient mutant hrcC could suppress PEN3 accumulation. Moreover, transgenic overexpression of the P. syringae pv. tomato DC3000 effector AvrPto was sufficient to suppress PEN3 focal accumulation in response to flg22. Analyses of P. syringae pv. tomato DC3000 effector deletion mutants showed that individual effectors, including AvrPto, appear to be insufficient to suppress PEN3 accumulation when delivered by bacteria, suggesting a requirement for a combined action of multiple effectors. Collectively, our results indicate that PEN3 plays a positive role in plant resistance to a bacterial pathogen and show that focal accumulation of PEN3 protein may be a useful cellular response marker for the Arabidopsis–P. syringae interaction.

Graminicolous powdery mildew fungi as new natural hosts of Ampelomyces mycoparasites

1997 ◽  
Vol 75 (4) ◽  
pp. 680-683 ◽  
Author(s):  
Levente Kiss
Keyword(s):  
Powdery Mildew ◽  
Poa Pratensis ◽  
Blumeria Graminis ◽  
Erysiphe Graminis ◽  
Natural Occurrence ◽  
Powdery Mildews ◽  
Two Samples ◽  
Natural Hosts ◽  
Powdery Mildew Fungi ◽  
Cultivated Species

The natural occurrence of Ampelomyces mycoparasites is reported for the first time in hyphae, conidiophores, and immature cleistothecia of Blumeria graminis (syn. Erysiphe graminis), the causal agent of cereal and grass powdery mildews. During a 4-year search for Ampelomyces on leaves of different wild and cultivated species of the Gramineae infected with powdery mildews in Hungary, Ampelomyces was recorded in only two samples that represent 5% of the collected monocotyledons. The host plants of B. graminis parasitized by Ampelomyces were Hordeum murinum and Poa pratensis. The pycnidia of Ampelomyces were present in only 3–10% of the powdery mildew mycelia. These observations suggest that (i) the natural occurrence of Ampelomyces mycoparasites on monocotyledons infected with powdery mildews is rare compared with their repeatedly reported incidence on dicotyledons infected with different powdery mildew fungi, and (ii) they probably do not have any significant role in the natural control of B. graminis in the field. Key words: Ampelomyces, Blumeria graminis, Erysiphe graminis, Gramineae, hyperparasitism, mycoparasitism.

Genome Expansion and Gene Loss in Powdery Mildew Fungi Reveal Tradeoffs in Extreme Parasitism

Science ◽  
2010 ◽  
Vol 330 (6010) ◽  
pp. 1543-1546 ◽  
Author(s):  
Pietro D. Spanu ◽  
James C. Abbott ◽  
Joelle Amselem ◽  
Timothy A. Burgis ◽  
Darren M. Soanes ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Life Style ◽  
Living Plant ◽  
Powdery Mildews ◽  
Primary And Secondary Metabolism ◽  
Core Set ◽  
Barley Powdery Mildew ◽  
Dicotyledonous Plants ◽  
Powdery Mildew Fungi ◽  
Species Specific

Powdery mildews are phytopathogens whose growth and reproduction are entirely dependent on living plant cells. The molecular basis of this life-style, obligate biotrophy, remains unknown. We present the genome analysis of barley powdery mildew, Blumeria graminis f.sp. hordei (Blumeria), as well as a comparison with the analysis of two powdery mildews pathogenic on dicotyledonous plants. These genomes display massive retrotransposon proliferation, genome-size expansion, and gene losses. The missing genes encode enzymes of primary and secondary metabolism, carbohydrate-active enzymes, and transporters, probably reflecting their redundancy in an exclusively biotrophic life-style. Among the 248 candidate effectors of pathogenesis identified in the Blumeria genome, very few (less than 10) define a core set conserved in all three mildews, suggesting that most effectors represent species-specific adaptations.

scholarly journals GFP transformation sheds more light on a widespread mycoparasitic interaction

2019 ◽  
Author(s):  
Márk Z. Németh ◽  
Alexandra Pintye ◽  
Áron N. Horváth ◽  
Pál Vági ◽  
Gábor M. Kovács ◽  
...  
Keyword(s):  
Plant Pathogens ◽  
Fluorescent Protein ◽  
Environmental Fate ◽  
Molecular Genetic ◽  
Powdery Mildews ◽  
Before And After ◽  
Mycoparasitic Fungi ◽  
Green Fluorescent ◽  
First Time ◽  
Plant Surfaces

ABSTRACTPowdery mildews (PMs), ubiquitous obligate biotrophic plant pathogens, are often attacked in the field by mycoparasitic fungi belonging to the genus Ampelomyces. Some Ampelomyces strains are commercialized biocontrol agents of crop pathogenic PMs. Using Agrobacterium tumefaciens-mediated transformation (ATMT), we produced stable Ampelomyces transformants that constitutively expressed the green fluorescent protein (GFP), to (i) improve the visualization of the PM-Ampelomyces interaction; and (ii) decipher the environmental fate of Ampelomyces before and after acting as a mycoparasite. Detection of Ampelomyces structures, and especially hyphae, was greatly enhanced when diverse PM, leaf and soil samples containing GFP transformants were examined with fluorescence microscopy compared to brightfield and DIC optics. We showed for the first time that Ampelomyces can persist up to 21 days on PM-free host plant surfaces, where it can attack PM structures as soon as these appear after this period. As a saprobe in decomposing, PM-infected leaves on the ground, and also in autoclaved soil, Ampelomyces developed new hyphae, but did not sporulate. These results indicate that Ampelomyces occupies a niche in the phyllosphere where it acts primarily as a mycoparasite of PMs. Our work has established a framework for a molecular genetic toolbox for Ampelomyces using ATMT.

scholarly journals First records of powdery mildew fungi (Erysiphales) on medicinal plants in Taiwan

2021 ◽  
Author(s):  
Yu-Wei Yeh ◽  
Pei-Yi Chou ◽  
Hsin-Yu Hou ◽  
Roland Kirschner
Keyword(s):  
Powdery Mildew ◽  
Medicinal Plants ◽  
Species Identification ◽  
Host Plants ◽  
New Records ◽  
Its Sequences ◽  
New Host ◽  
Powdery Mildews ◽  
Eryngium Foetidum ◽  
Powdery Mildew Fungi

Abstract Background: Production of medicinal plants in Taiwan is not only hampered by international market competition, but also lack of knowledge of their pathogens, such as powdery mildew fungi (Erysiphales, Ascomycota). Records of these fungi in Taiwan originate from few researchers for the last one hundred years and are still incomplete. Since powdery mildews in tropical/subtropical environments rarely develop the sexual stages with morphologically diagnostic characteristics, internal transcribed spacer sequences (ITS) of the ribosomal RNA genes obtained from the asexual stages have become important modern tools for species identification.Results: Powdery mildews on medicinal plants from educational and ornamental plantations in Taiwan were identified based on the anamorph morphology and ITS sequences. Four powdery mildews on medicinal plants are new records for Taiwan, Arthrocladiella mougeotii on Lycium chinense, Erysiphe glycines on Pueraria lobata, Erysiphe lespedezae on Bauhinia sp., Desmodium caudatum, and Uraria crinita, and E. lonicerae on Lonicera japonica. Eryngium foetidum is a new host for Erysiphe heraclei hitherto known on other host plants in Taiwan. Eryngium foetidum and Uraria crinita are new host plants for powdery mildews worldwide. Only specific field collection of the pathogens yielded the new records, not checking plant specimens in a phanerogam herbarium. The pathogens did not cause death of the host plants, but appeared to enhance stress by infection of mature leaves.Conclusions: Taxonomic study of powdery mildews in Taiwan results into new host records of economically important medicinal plants in Taiwan with potential consequences for plant production and quarantine and also shows that host records are quite incomplete worldwide. Although ITS sequences were useful for species identification, the lack of data for several species on the same host genus on the one hand and the low variation between closely related species on the other indicate the need for further study.

The Host-Haustorium Interface in Powdery Mildews

1989 ◽  
Vol 16 (1) ◽  
pp. 45 ◽  
Author(s):  
JM Manners
Keyword(s):  
Powdery Mildew ◽  
Recombinant Dna ◽  
Powdery Mildews ◽  
Successful Infection ◽  
Powdery Mildew Fungi ◽  
Experimental Approaches ◽  
And Function ◽  
Host Parasite ◽  
Physical Manipulation ◽  
Detailed Molecular Analysis

The powdery mildew fungi have proven to be a useful model system for studies of the host-parasite interface in biotrophic parasitism. Investigation of the interface has requrred the development of novel experimental approaches, for example the isolation of populations of haustoria in association with other interface components and the chemical and physical manipulation of living isolated epidermal strips infected wth powdery mildew fungi. These experimental approaches have provided information on the nature of metabolites transferred from host to pathogen at the interface and on the underlymg mechanisms. Studies of incompatible interactions with powdery mildew fungi have indicated that the establishment of a functional host-haustorial interface is critical for successful infection. In future, the application of recombinant DNA and monoclonal antibody technologies to the host-haustorium interface of powdery mildews should lead to a more detailed molecular analysis of the interface, and thus provide new insights into its structure and function.

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