An epi-evolutionary model to predict spore-producing pathogens adaptation to quantitative resistance in heterogeneous environments

Mapping Intimacies ◽

10.1101/423467 ◽

2018 ◽

Author(s):

Ramsès Djidjou-Demasse ◽

Jean-Baptiste Burie ◽

Arnaud Ducrot ◽

Sébastien Lion ◽

Quentin Richard ◽

...

Keyword(s):

Latent Period ◽

Fungal Pathogens ◽

Plant Pathogens ◽

Evolutionary Dynamics ◽

Quantitative Resistance ◽

Evolutionary Model ◽

Infectious Period ◽

Heterogeneous Environments ◽

Differential Model ◽

Infection Efficiency

AbstractIn contrast to the many theoretical studies on the adaptation of plant pathogens to qualitative resistances, few studies have investigated how quantitative resistance selects for increased pathogen aggressiveness. We formulate an integro-differential model with nonlocal effects of mutations to describe the evolutionary epidemiology dynamics of spore-producing pathogens in heterogeneous agricultural environments sharing a well-mixed pool of spores. Parasites reproduce clonally and each strain is characterized by pathogenicity traits corresponding to the epidemic process: (i) infection efficiency and (ii) sporulation curve (including the latent period, the total spore production and the shape of the sporulation curve). We first derive a general expression of the basic reproduction numberfor fungal pathogens in heterogeneous host environments. Next, by characterizing evolutionary attractors, we investigate how the choice of quantitative resistances altering pathogenicity traits impacts the evolutionary dynamics of the pathogen population both at equilibrium and during transient epidemiological dynamics. We show that evolutionary attractors of the model coincide with local maxima of theonly for traits involved in the sporulation curve. Quantitative resistance impacting the sporulation curve will always select a monomorphic population while dimorphism can occur with resistance altering infection efficiency. We also highlight how the shape of the relationship between the latent period and the total number of spores produced during the infectious period, impacts resistance durability and how to take advantage of evolutionary dynamics to increase the durability of quantitative resistance. Our analyses can guide experimentations by providing testable hypotheses and help plant breeders to design breeding programs.

An epi‐evolutionary model for predicting the adaptation of spore‐producing pathogens to quantitative resistance in heterogeneous environments

Evolutionary Applications ◽

10.1111/eva.13328 ◽

2021 ◽

Author(s):

Frédéric Fabre ◽

Jean‐Baptiste Burie ◽

Arnaud Ducrot ◽

Sébastien Lion ◽

Quentin Richard ◽

...

Keyword(s):

Quantitative Resistance ◽

Evolutionary Model ◽

Heterogeneous Environments

The Potential of Rhizoctonia-Like Fungi for the Biological Protection of Cereals against Fungal Pathogens

Plants ◽

10.3390/plants10020349 ◽

2021 ◽

Vol 10 (2) ◽

pp. 349

Author(s):

Dominik Bleša ◽

Pavel Matušinský ◽

Romana Sedmíková ◽

Milan Baláž

Keyword(s):

Biological Control ◽

Fungal Pathogens ◽

Plant Pathogens ◽

Higher Plants ◽

Fusarium Culmorum ◽

Suppressive Effect ◽

Plant Production ◽

Shoot Biomass ◽

Organic Substrates

The use of biological control is becoming a common practice in plant production. One overlooked group of organisms potentially suitable for biological control are Rhizoctonia-like (Rh-like) fungi. Some of them are capable of forming endophytic associations with a large group of higher plants as well as mycorrhizal symbioses. Various benefits of endophytic associations were proved, including amelioration of devastating effects of pathogens such as Fusarium culmorum. The advantage of Rh-like endophytes over strictly biotrophic mycorrhizal organisms is the possibility of their cultivation on organic substrates, which makes their use more suitable for production. We focused on abilities of five Rh-like fungi isolated from orchid mycorrhizas, endophytic fungi Serendipita indica, Microdochium bolleyi and pathogenic Ceratobasidium cereale to inhibit the growth of pathogenic F. culmorum or Pyrenophora teres in vitro. We also analysed their suppressive effect on wheat infection by F. culmorum in a growth chamber, as well as an effect on barley under field conditions. Some of the Rh-like fungi affected the growth of plant pathogens in vitro, then the interaction with plants was tested. Beneficial effect was especially noted in the pot experiments, where wheat plants were negatively influenced by F. culmorum. Inoculation with S. indica caused higher dry shoot biomass in comparison to plants treated with fungicide. Prospective for future work are the effects of these endophytes on plant signalling pathways, factors affecting the level of colonization and surviving of infectious particles.

The Ustilago hordei–Barley Interaction is a Versatile System for Characterization of Fungal Effectors

Journal of Fungi ◽

10.3390/jof7020086 ◽

2021 ◽

Vol 7 (2) ◽

pp. 86

Author(s):

Bilal Ökmen ◽

Daniela Schwammbach ◽

Guus Bakkeren ◽

Ulla Neumann ◽

Gunther Doehlemann

Keyword(s):

Fungal Pathogens ◽

Plant Pathogens ◽

Expression System ◽

Pathogenic Fungi ◽

Effector Proteins ◽

Mating Partner ◽

Fungal Virulence ◽

Functional Studies ◽

Infection Structures ◽

Ustilago Hordei

Obligate biotrophic fungal pathogens, such as Blumeria graminis and Puccinia graminis, are amongst the most devastating plant pathogens, causing dramatic yield losses in many economically important crops worldwide. However, a lack of reliable tools for the efficient genetic transformation has hampered studies into the molecular basis of their virulence or pathogenicity. In this study, we present the Ustilago hordei–barley pathosystem as a model to characterize effectors from different plant pathogenic fungi. We generate U. hordei solopathogenic strains, which form infectious filaments without the presence of a compatible mating partner. Solopathogenic strains are suitable for heterologous expression system for fungal virulence factors. A highly efficient Crispr/Cas9 gene editing system is made available for U. hordei. In addition, U. hordei infection structures during barley colonization are analyzed using transmission electron microscopy, showing that U. hordei forms intracellular infection structures sharing high similarity to haustoria formed by obligate rust and powdery mildew fungi. Thus, U. hordei has high potential as a fungal expression platform for functional studies of heterologous effector proteins in barley.

Potential New Herbicides – Phytotoxins from Plant Pathogens

Weed Technology ◽

10.1017/s0890037x00032383 ◽

1988 ◽

Vol 2 (4) ◽

pp. 519-524 ◽

Cited By ~ 17

Author(s):

Doug Kenfield ◽

Greg Bunkers ◽

Gary A. Strobel ◽

Fumio Sugawara

Keyword(s):

Organic Synthesis ◽

Fungal Pathogens ◽

Plant Pathogens ◽

Biological Activities ◽

Biological Data

A rationale for the study of phytotoxins from fungal pathogens of plants is presented. Structural chemistries and biological data are given for numerous, recently discovered phytotoxins in such diverse chemical classes as polyketides, terpenoids, diketopiperazines, and isocoumarins. The biological activities of these compounds range from broadly toxic (curvulin) to host specific (maculosin-1). Phytotoxicology offers a viable supplement to organic synthesis as a means of developing and implementing new, biorational, and economical herbicides.

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.;

Establishment, contagiousness, and initial spread of SARS-CoV-2 in Canada

FACETS ◽

10.1139/facets-2020-0055 ◽

2021 ◽

Vol 6 (1) ◽

pp. 180-194

Author(s):

Martin Krkošek ◽

Madeline Jarvis-Cross ◽

Kiran Wadhawan ◽

Isha Berry ◽

Jean-Paul R. Soucy ◽

...

Keyword(s):

Latent Period ◽

Bayesian Framework ◽

Contact Tracing ◽

Transmission Model ◽

Infectious Period ◽

Median Reduction ◽

Community Transmission

This study empirically quantifies dynamics of SARS-CoV-2 establishment and early spread in Canada. We developed a transmission model that was simulation tested and fitted in a Bayesian framework to timeseries of new cases per day prior to physical distancing interventions. A hierarchical version was fitted to all provinces simultaneously to obtain average estimates for Canada. Across scenarios of a latent period of 2–4 d and an infectious period of 5–9 d, the R0 estimate for Canada ranges from a minimum of 3.0 (95% CI: 2.3–3.9) to a maximum of 5.3 (95% CI: 3.9–7.1). Among provinces, the estimated commencement of community transmission ranged from 3 d before to 50 d after the first reported case and from 2 to 25 d before the first reports of community transmission. Among parameter scenarios and provinces, the median reduction in transmission needed to obtain R0 < 1 ranged from 46% (95% CI: 43%–48%) to 89% (95% CI: 88%–90%). Our results indicate that local epidemics of SARS-CoV-2 in Canada entail high levels of stochasticity, contagiousness, and observation delay, which facilitates rapid undetected spread and requires comprehensive testing and contact tracing for its containment.

The Potential Use of Isothermal Amplification Assays for In-Field Diagnostics of Plant Pathogens

Plants ◽

10.3390/plants10112424 ◽

2021 ◽

Vol 10 (11) ◽

pp. 2424

Author(s):

Aleksandr V. Ivanov ◽

Irina V. Safenkova ◽

Anatoly V. Zherdev ◽

Boris B. Dzantiev

Keyword(s):

Molecular Diagnostics ◽

Fungal Pathogens ◽

Plant Pathogens ◽

Isothermal Amplification ◽

Detection Methods ◽

Nucleic Acid Detection ◽

Advantages And Disadvantages ◽

Fungal Phytopathogens ◽

Highly Sensitive Detection ◽

And Control

Rapid, sensitive, and timely diagnostics are essential for protecting plants from pathogens. Commonly, PCR techniques are used in laboratories for highly sensitive detection of DNA/RNA from viral, viroid, bacterial, and fungal pathogens of plants. However, using PCR-based methods for in-field diagnostics is a challenge and sometimes nearly impossible. With the advent of isothermal amplification methods, which provide amplification of nucleic acids at a certain temperature and do not require thermocyclic equipment, going beyond the laboratory has become a reality for molecular diagnostics. The amplification stage ceases to be limited by time and instruments. Challenges to solve involve finding suitable approaches for rapid and user-friendly plant preparation and detection of amplicons after amplification. Here, we summarize approaches for in-field diagnostics of phytopathogens based on different types of isothermal amplification and discuss their advantages and disadvantages. In this review, we consider a combination of isothermal amplification methods with extraction and detection methods compatible with in-field phytodiagnostics. Molecular diagnostics in out-of-lab conditions are of particular importance for protecting against viral, bacterial, and fungal phytopathogens in order to quickly prevent and control the spread of disease. We believe that the development of rapid, sensitive, and equipment-free nucleic acid detection methods is the future of phytodiagnostics, and its benefits are already visible.

Biochar and Trichoderma spp. in management of plant diseases caused by soilborne fungal pathogens: a review and perspective

Research Society and Development ◽

10.33448/rsd-v10i15.22465 ◽

2021 ◽

Vol 10 (15) ◽

pp. e296101522465

Author(s):

Erika Valente de Medeiros ◽

Lucas Figueira da Silva ◽

Jenifer Sthephanie Araújo da Silva ◽

Diogo Paes da Costa ◽

Carlos Alberto Fragoso de Souza ◽

...

Keyword(s):

Soil Properties ◽

Fungal Pathogens ◽

Plant Disease ◽

Plant Pathogens ◽

Plant Diseases ◽

Management Tool ◽

Production Plant ◽

Trichoderma Spp ◽

Health Concept ◽

Plant Disease Management

A better understanding of the use of biochar with Trichoderma spp. (TRI), considered the most studied tool for biological control, would increase our ability to set priorities. However, no studies exist using the two inputs on plant disease management. Here, we hypothesized that biochar and TRI would be used for the management of soilborne plant pathogens, mainly due to changes in soil properties and its interactions. To test this hypothesis, this review assesses papers that used biochar and TRI against plant diseases and we summarize the handling mechanisms for each input. Biochar acts by mechanisms: induction to plant resistance, sorption of allelopathic and fungitoxic compounds, increase of beneficial microorganisms, changes the soil properties that promote health and nutrient availability. Trichoderma as biocontrol agents by different mechanisms: mycoparasitism, enzyme and secondary metabolic production, plant promoter agent, natural decomposition agent, and biological agent of bioremediation. Overall, our findings expand our knowledge about the reuse of wastes transformed in biochar combined with Trichoderma has potential perspective to formulate products as alternative management tool of plant disease caused by soilborne fungal pathogen and add important information that can be suitable for development of strategy for use in the global health concept.

Assessing Performance of Spore Samplers in Monitoring Aeromycobiota and Fungal Plant Pathogen Diversity in Canada

Applied and Environmental Microbiology ◽

10.1128/aem.02601-17 ◽

2018 ◽

Vol 84 (9) ◽

Cited By ~ 11

Author(s):

Wen Chen ◽

Sarah Hambleton ◽

Keith A. Seifert ◽

Odile Carisse ◽

Moussa S. Diarra ◽

...

Keyword(s):

Prince Edward Island ◽

Fungal Pathogens ◽

Plant Pathogens ◽

High Throughput Sequencing ◽

Climatic Factors ◽

Weather Conditions ◽

Pilot Project ◽

Sampling Location ◽

Fungal Community Composition ◽

Content Type

ABSTRACTSpore samplers are widely used in pathogen surveillance but not so much for monitoring the composition of aeromycobiota. In Canada, a nationwide spore-sampling network (AeroNet) was established as a pilot project to assess fungal community composition in air and rain samples collected using three different spore samplers in the summers of 2010 and 2011. Metabarcodes of the internal transcribed spacer (ITS) were exhaustively characterized for three of the network sites, in British Columbia (BC), Québec (QC), and Prince Edward Island (PEI), to compare performance of the samplers. Sampler type accounted for ca. 20% of the total explainable variance in aeromycobiota compositional heterogeneity, with air samplers recovering more Ascomycota and rain samplers recovering more Basidiomycota. Spore samplers showed different abilities to collect 27 fungal genera that are plant pathogens. For instance,Cladosporiumspp.,Drechsleraspp., andEntylomaspp. were collected mainly by air samplers, whileFusariumspp.,Microdochiumspp., andUstilagospp. were recovered more frequently with rain samplers. The diversity and abundance of some fungi were significantly affected by sampling location and time (e.g.,AlternariaandBipolaris) and weather conditions (e.g.,MycocentrosporaandLeptosphaeria), and depended on using ITS1 or ITS2 as the barcoding region (e.g.,EpicoccumandBotrytis). The observation that Canada's aeromycobiota diversity correlates with cooler, wetter conditions and northward wind requires support from more long-term data sets. Our vision of the AeroNet network, combined with high-throughput sequencing (HTS) and well-designed sampling strategies, may contribute significantly to a national biovigilance network for protecting plants of agricultural and economic importance in Canada.IMPORTANCEThe current study compared the performance of spore samplers for collecting broad-spectrum air- and rain-borne fungal pathogens using a metabarcoding approach. The results provided a thorough characterization of the aeromycobiota in the coastal regions of Canada in relation to the influence of climatic factors. This study lays the methodological basis to eventually develop knowledge-based guidance on pest surveillance by assisting in the selection of appropriate spore samplers.

Host-parasite relationships in bean cultivars of varying susceptibility to bean rust

Canadian Journal of Botany ◽

10.1139/b99-104 ◽

2000 ◽

Vol 77 (11) ◽

pp. 1551-1559 ◽

Cited By ~ 1

Author(s):

M W Harding ◽

J C Stutz ◽

R W Roberson

Keyword(s):

Phaseolus Vulgaris ◽

Latent Period ◽

Rust Fungus ◽

Freeze Substitution ◽

Infected Leaf ◽

Bean Rust ◽

Infection Efficiency ◽

Host Cytoplasm ◽

Short Latent Period ◽

Host Parasite

Components of disease development were measured in three cultivars of Phaseolus vulgaris L. (common bean) infected with Uromyces appendiculatus (Pers.:Pers.) Unger (bean rust fungus) race O. Disease measurements and light and electron microscope data of host-parasite relationships were obtained and analyzed. Uredinial size, infection efficiency, latent period, and fungal colony radius were measured from infected bean leaves that were grown under controlled conditions. Phaseolus vulgaris cultivar Pinto 111, a highly susceptible check, displayed the largest uredinia, the highest infection efficiency, large colony radii, and a short latent period. Cultivars Early Gallatin and Kentucky Wonder (K.W.) 814 displayed moderate and low susceptibility, respectively. Cultivar Early Gallatin had smaller uredinia, reduced infection efficiency, and longer latent period when compared with cv. Pinto 111. Cultivar K.W. 814 was characterized by minute pustules, restricted colony expansion, and the longest latent period. Ultrastructural data of host-parasite relationships were collected from infected leaf tissues and prepared for transmission electron microscopy by high-pressure cryofixation and freeze substitution. In 'Pinto 111' the collars around haustorial necks were composed of a fibrillar network embedded in an electron transparent matrix. Ultrastructural observations indicated that Cultivars K.W. 814 and Early Gallatin deposited more collar material than 'Pinto 111.' Networks of tubular endomembranes developed near the host-parasite interface in the host cytoplasm of cultivars K.W. 814 and Early Gallatin. The tubules showed continuity with the extrahaustorial membrane and contained an amorphous, electron-dense material in the lumen. Tubular endomembranes were not seen in the highly susceptible cultivar Pinto 111.