Estimation of Leaf Wetness Duration Requirements of Foliar Fungal Pathogens with Uncertain Data—An Application to Mycosphaerella nawae

Wetness of the host surface is a critical environmental factor for the development of foliar fungal diseases, but it is difficult to estimate the wetness durations required by pathogens for infection when only few experimental data are available. In this paper, we propose a method to estimate wetness duration requirements of foliar fungal pathogens when precise experimental data are not available. The proposed method is based on approximate Bayesian computation. It only requires lower and upper bounds of wetness duration requirements for one or fewer temperatures. We describe the method, show how to apply it to an infection model, and then present a case study on Mycosphaerella nawae, the causal agent of circular leaf spot of persimmon. In this example, the parameters of a simple infection model were estimated using experimental data found in the literature for the pathogen, and the model was applied to assess the risk in a Spanish area recently affected by the disease. The results showed that the probability of successful infection was higher than 0.5 for 32% of the on-site wetness durations recorded in the affected area. Results obtained with simulated data showed that our method was able to improve the estimation of wetness duration requirement. Given the flexibility of the proposed method, we expect it to become adopted for assessing the risk of introduction of exotic fungal plant pathogens.

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The emergence of cereal fungal diseases and the incidence of leaf spot diseases in Finland

Agricultural and Food Science ◽

10.2137/145960611795163015 ◽

2008 ◽

Vol 20 (1) ◽

pp. 62 ◽

Cited By ~ 7

Author(s):

M. JALLI ◽

P. LAITINEN ◽

S. LATVALA

Keyword(s):

Spring Wheat ◽

Leaf Spot ◽

Fungal Pathogens ◽

Plant Pathogens ◽

Field Survey ◽

Fungal Diseases ◽

Cochliobolus Sativus ◽

Pyrenophora Tritici Repentis ◽

Fungal Plant Pathogens ◽

First Time

Fungal plant pathogens causing cereal diseases in Finland have been studied by a literature survey, and a field survey of cereal leaf spot diseases conducted in 2009. Fifty-seven cereal fungal diseases have been identified in Finland. The first available references on different cereal fungal pathogens were published in 1868 and the most recent reports are on the emergence of Ramularia collo-cygni and Fusarium langsethiae in 2001. The incidence of cereal leaf spot diseases has increased during the last 40 years. Based on the field survey done in 2009 in Finland, Pyrenophora teres was present in 86%, Cochliobolus sativus in 90% and Rhynchosporium secalis in 52% of the investigated barley fields. Mycosphaerella graminicola was identified for the first time in Finnish spring wheat fields, being present in 6% of the studied fields. Stagonospora nodorum was present in 98% and Pyrenophora tritici-repentis in 94% of spring wheat fields. Oat fields had the fewest fungal diseases. Pyrenophora chaetomioides was present in 63% and Cochliobolus sativus in 25% of the oat fields studied.;

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Localization and Visualization of Specific Gene Products in Fungal Plant Pathogens

Microscopy and Microanalysis ◽

10.1017/s1431927600035893 ◽

2000 ◽

Vol 6 (S2) ◽

pp. 680-681 ◽

Cited By ~ 2

Author(s):

T. M. Bourett ◽

K. J. Czymmek ◽

T. M. Dezwaan ◽

J. A. Sweigard ◽

R. J. Howard

Keyword(s):

Fungal Pathogens ◽

Plant Pathogens ◽

Protein Localization ◽

Infected Plant ◽

Cell Interaction ◽

Specific Gene ◽

Gene Products ◽

Tem Analysis ◽

Fungal Plant Pathogens ◽

Plant Pathogenesis

Specific gene products of both pathogens and hosts have been implicated as decisive elements during plant pathogenesis. While expression of some of these genes is constitutive, that of others is likely ephemeral and activated only during a particular stage of the interaction. Because the relative timing of expression may be critical, transcription and translation have often been addressed by extracting mRNA and proteins from infected plant tissue. This approach, however, cannot readily detect proteins of low abundance in bulk samples nor offer much useful information on cell-cell interaction. Only a cytological analysis that employs microscopy can resolve the temporal and spatial details of gene expression. Typically, such protein localization studies have required specific antibodies, but these large probe molecules do not diffuse into living or conventionally fixed cells of either fungal pathogens or plant hosts. For TEM analysis, these permeability-imposed limitations have been reduced by thin sectioning to render accessible antibody binding sites.

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Nonhost Resistance in Arabidopsis-Colletotrichum Interactions Acts at the Cell Periphery and Requires Actin Filament Function

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-19-0270 ◽

2006 ◽

Vol 19 (3) ◽

pp. 270-279 ◽

Cited By ~ 109

Author(s):

Chiyumi Shimada ◽

Volker Lipka ◽

Richard O'Connell ◽

Tetsuro Okuno ◽

Paul Schulze-Lefert ◽

...

Keyword(s):

Actin Filament ◽

Fungal Pathogens ◽

Plant Pathogens ◽

Fluorescent Protein ◽

Molecular Genetic ◽

Molecular Genetic Analysis ◽

Nonhost Resistance ◽

Cell Periphery ◽

Colletotrichum Species ◽

Fungal Plant Pathogens

Pathogenesis of nonadapted fungal pathogens is often terminated coincident with their attempted penetration into epidermal cells of nonhost plants. The genus Colletotrichum represents an economically important group of fungal plant pathogens that are amenable to molecular genetic analysis. Here, we investigated interactions between Arabidopsis and Colletotrichum to gain insights in plant and pathogen processes activating nonhost resistance responses. Three tested nonadapted Colletotrichum species differentiated melanized appressoria on Arabidopsis leaves but failed to form intracellular hyphae. Plant cells responded to Colletotrichum invasion attempts by the formation of PMR4/GSL5-dependent papillary callose. Appressorium differentiation and melanization were insufficient to trigger this localized plant cell response, but analysis of nonpathogenic C. lagenarium mutants implicates penetration-peg formation as the inductive cue. We show that Arabidopsis PEN1 syntaxin controls timely accumulation of papillary callose but is functionally dispensable for effective preinvasion (penetration) resistance in nonhost interactions. Consistent with this observation, green fluorescent protein-tagged PEN1 did not accumulate at sites of attempted penetration by either adapted or nonadapted Colletotrichum species, in contrast to the pronounced focal accumulations of PEN1 associated with entry of powdery mildews. We observed extensive reorganization of actin microfilaments leading to polar orientation of large actin bundles towards appressorial contact sites in interactions with the nonadapted Colletotrichum species. Pharmacological inhibition of actin filament function indicates a functional contribution of the actin cytoskeleton for both preinvasion resistance and papillary callose formation. Interestingly, the incidence of papilla formation at entry sites was greatly reduced in interactions with C. higginsianum isolates, indicating that this adapted pathogen may suppress preinvasion resistance at the cell periphery.

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A GENERIC INFECTION MODEL TO COMPARE AIRBORNE FUNGAL PLANT PATHOGENS FOR CLIMATE CHANGE STUDIES

Acta Horticulturae ◽

10.17660/actahortic.2015.1068.21 ◽

2015 ◽

pp. 171-178

Author(s):

J. Caubel ◽

G. Bourgeois ◽

M. Launay ◽

F. Huard ◽

N. Brisson

Keyword(s):

Climate Change ◽

Plant Pathogens ◽

Infection Model ◽

Fungal Plant Pathogens

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Cecropin A—Derived Peptides Are Potent Inhibitors of Fungal Plant Pathogens

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.1998.11.3.218 ◽

1998 ◽

Vol 11 (3) ◽

pp. 218-227 ◽

Cited By ~ 107

Author(s):

Laura Cavallarin ◽

David Andreu ◽

Blanca San Segundo

Keyword(s):

Fungal Pathogens ◽

Plant Pathogens ◽

Crop Protection ◽

Protective Effects ◽

Tomato Plants ◽

Hybrid Peptides ◽

Cecropin A ◽

Naturally Occurring ◽

Fungal Plant Pathogens ◽

Α Helix

Cecropins are naturally occurring peptides that play an important role in the immune response of insects. Cecropin A-derived and cecropin A-melittin hybrid peptides, all smaller than the natural compound cecropin A, were synthesized and tested for their ability to inhibit growth of several agronomically important fungal pathogens. We found that an 11-amino-acid sequence, corresponding to the N-terminal amphipathic α-helix domain of cecropin A, exhibited antifungal activity. Differences in susceptibility of the various pathogens were observed, Phytophthora infestans being particularly sensitive to the shortened cecropin A peptides (IC50 = 2 × 10−6 M). Biotoxicity of the shortest cecropin A-derived peptide was variously affected by the presence of proteins extracted from leaves of tobacco and tomato plants, either total extracts or intercellular fluids (ICFs). Overall, there was a greater tolerance to tomato protein extracts than to tobacco extracts. These findings suggest that tobacco should not be used as a model for testing the possible protective effects of transgenically expressed, cecropin-based genes. The feasibility of tailoring cecropin A genes to enhance crop protection in particular plant/fungus combinations is discussed.

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Effector proteins of extracellular fungal plant pathogens that trigger host resistance

Functional Plant Biology ◽

10.1071/fp10077 ◽

2010 ◽

Vol 37 (10) ◽

pp. 901 ◽

Cited By ~ 11

Author(s):

Ann-Maree Catanzariti ◽

David A. Jones

Keyword(s):

Biological Activity ◽

Host Resistance ◽

Fungal Pathogens ◽

Plant Pathogens ◽

Molecular Mechanisms ◽

Host Tissue ◽

Effector Proteins ◽

Resistance Proteins ◽

Recognitional Capacity ◽

Fungal Plant Pathogens

An understanding of the molecular mechanisms that plant pathogens use to successfully colonise host tissue can be gained by studying the biological activity of pathogen proteins secreted during infection. Several secreted ‘effector’ proteins with possible roles in virulence have been isolated from extracellular fungal pathogens, including three that have been shown to negate host defences. In most cases, significant effector variation is observed between different pathogen isolates, driven by the recognitional capacity of disease resistance proteins arrayed against the pathogen by the host plant. This review summarises what is known about the expression, function and variation of effectors isolated from extracellular fungal pathogens.

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Diversity of biocontrol agents, isolated from several sources, inhibitory to several fungal plant pathogens

Biodiversitas Journal of Biological Diversity ◽

10.13057/biodiv/d220136 ◽

2020 ◽

Vol 22 (1) ◽

Author(s):

Yan Ramona ◽

IDA BAGUS GEDE DARMAYASA ◽

ANAK AGUNG NGURAH NARA KUSUMA ◽

Martin Line

Keyword(s):

Fungal Pathogens ◽

Plant Pathogens ◽

Antagonistic Activity ◽

Significant Inhibition ◽

Biocontrol Agents ◽

Dual Culture ◽

Rdna Sequences ◽

Fungal Plant Pathogens ◽

Mature Compost

Abstract. Ramona Y, Darmayasa IBG, Kusuma AANN, Line MA. 2021. Diversity of biocontrol agents, isolated from several sources, inhibitory to several fungal plant pathogens. Biodiversitas 22: 298-303. This study investigated the inhibitory potential of diversity of antagonist bacteria residing in the rhizosphere zone and mature compost to counter fungal plant pathogens. Soils collected from rhizosphere of lettuce farms in Bali-Indonesia and Tasmania-Australia, mature compost, commercial biocontrol (Dipel®), and laboratory contaminants with significant inhibition against tested fungal pathogens were used as sources of antagonist bacteria. These antagonists were isolated by applying dilution and spread method on trypticase soya agar (TSA) or potato dextrose agar (PDA), and their ability to inhibit Sclerotinia minor, Sclerotinia sclerotiorum, Fusarium spp., and Rhizoctonia solani was assessed in dual culture assays. The results showed that 67 out of more than 100 isolates had antagonistic activity in vitro against at least one of tested fungal pathogens. In the preliminary identification, Bacillus spp. or Pseudomonas spp. were found to be pre-dominant isolates. Following screening studies in a non-replicated glasshouse experiment against S. minor and S. sclerotiorum, 8 of the most promising isolates were further identified using molecular methods based on their 16s rDNA sequences aligned with those deposited at the GeneBank. These 8 isolates were identified as Pseudomonas corrugata, Bacillus megaterium, Bacillus polymyxa, Bacillus mojavensis, Bacillus pumilus, Bacillus thuringiensis, Exiguobacterium acetylicum, and Chryseobacterium indologenes.

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Growth-inhibiting activity of citronella essential oil to multiple fungal plant pathogens

10.1101/860718 ◽

2019 ◽

Author(s):

Mark Angelo O. Balendres ◽

Fe M. Dela Cueva

Keyword(s):

Essential Oil ◽

Growth Inhibition ◽

Spore Germination ◽

Mycelial Growth ◽

Fungal Pathogens ◽

Germ Tube ◽

Plant Pathogens ◽

Field Experiments ◽

Fungal Plant Pathogens ◽

Germ Tube Elongation

AbstractCymbopogon species are among the most reported essential oils with fungitoxic effect. In this study, mycelial growth of Fusarium oxysporum (banana wilt), Colletotrichum gloeosporioides (mango anthracnose), C. falcatum (sugarcane red rot) and Neopestalotiopsis spp. (mango leaf spot) as influenced by varying concentrations of citronella essential oil (CEO) was assessed in in vitro assays. Following growth inhibition test, spore germination and germ tube elongation of C. gloeosporioides were then examined. Mycelial growth of all test fungal pathogens was strongly inhibited by CEO, but variations were observed among fungal species. This growth inhibition activity was caused by the inhibition of spore germination and germ tube elongation as observed in C. gloeosporioides. The findings of this study show the strong growth-inhibitory activity of CEO to multiple fungal pathogens, indicating CEO’s potential as a chemical control approach against these fungal pathogens. Glasshouse and field experiments would establish CEO as one potential alternative to fungicides.

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‘Phytopathological strolls’ in the dual context of COVID-19 lockdown and IYPH2020: transforming constraints into an opportunity for public education about plant pathogens

10.1101/2021.02.03.429201 ◽

2021 ◽

Author(s):

Frédéric Suffert ◽

Muriel Suffert

Keyword(s):

Fungal Pathogens ◽

Plant Disease ◽

Plant Pathogens ◽

Digital Tools ◽

Pathogen Identification ◽

Open Spaces ◽

Powdery Mildews ◽

Fungal Plant Pathogens ◽

Large Audience ◽

The Times

AbstractThe experience presented here relates to 2020, a particularly timely year for plant disease-related communication (‘International Year of Plant Health’ IYPH2020), but also a unique year because of the COVID-19 pandemic. Our goal was to illustrate the diversity and beauty of fungal plant pathogens through a naturalist approach that could be followed by any amateur. We achieved this end through ‘phytopathological strolls’, in which we observed and determined the origin of symptoms on diseased plants found in our garden, in the local streets, in nearby open spaces, and sharing this matter with a broad public. The lockdown imposed in France created an additional motivation to take up the challenge, and to involve our children, even under strong constraints, such as movement restrictions. We observed and described fungal pathogens through hundreds of photographs, shared our findings with a large audience on Twitter, and received feedback. The material used was deliberately simple and transportable: a digital reflex camera, an old microscope, a mobile phone, some books and an Internet connexion. Between March 17 March and December 15, 2020 we found 148 plant pathogens, including 72 rusts, 22 powdery mildews and 22 septoria-like diseases. We discuss here the importance of promoting searches for plant pathogens, their description and conservation, through a combination of classical approaches and digital tools in tune with the times, such as Twitter, by treating pathogen identification like a detective game and, more surprisingly, by making use of the addictive nature of collection approaches, drawing a parallel with Pokémon Go.

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Fungal plant pathogens and soil biodiversity

Canadian Journal of Soil Science ◽

10.4141/s01-068 ◽

2003 ◽

Vol 83 (Special Issue) ◽

pp. 331-336 ◽

Cited By ~ 17

Author(s):

R. D. Reeleder

Keyword(s):

Disease Control ◽

Management Strategy ◽

Fungal Pathogens ◽

Plant Pathogens ◽

Molecular Techniques ◽

Control Measures ◽

Soil Biodiversity ◽

Naturally Occurring ◽

Fungal Plant Pathogens

The role of biodiversity as it affects the control of soil-borne fungal pathogens is discussed. Soil-borne fungal plant pathogens have often proven difficult to manage with conventional methods of disease control. Nonetheless, researchers have characterized several naturally occurring “disease-suppressive” soils where crop loss from disease is less than would otherwise be expected. Suppressive soils can also result from the incorporation of various amendments into soil. In most cases, disease control in such soils has been shown to be biological in nature; that is, soil organisms appear to directly or indirectly inhibit the development of disease. Increased knowledge of the identity and functioning of these organisms may support the development of techniques that can be used to develop suppressiveness in soils that are otherwise disease-conducive. Populations of pathogens themselves have been shown to exhibit considerable genetic diversity; the ability of populations to respond to disease control measures should be considered when developing a management strategy. New molecular techniques can be exploited to better characterize soil communities, including the pathogens themselves, as well as community responses to various disease control options. The contributions of Canadian researchers to these areas are discussed and models for further study are proposed. Key words: Biocontrol, molecular technologies, functional diversity, integrated pest management

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