Dynamics of fungal pathogens in host plant tissues

1995 ◽  
Vol 73 (S1) ◽  
pp. 1275-1283 ◽  
Author(s):  
Shigehito Takenaka
Keyword(s):  
Host Plant ◽  
Species Interactions ◽  
Fungal Biomass ◽  
Quantitative Methods ◽  
Plant Pathogens ◽  
Pathogenic Fungi ◽  
Molecular Methods ◽  
Plant Colonization ◽  
Fungal Colonization ◽  
Plant Tissues

To develop efficient control measures against fungal plant pathogens, the dynamics of host plant colonization during disease development and the interactions among fungi within host plant tissues need to be clarified. These studies require accurate quantitative estimation of specific fungal biomass in plant tissues. This has been approached by direct-microscopic methods, cultural methods, chemical determinations of fungal components, serological methods, and molecular methods. Among these methods, serological and molecular methods provide rapid, specific, and sensitive quantitative measures of fungal biomass in host plant tissues. Therefore, studies on fungal dynamics of host plant colonization using these two methods are presented. Some examples of species interactions among pathogenic fungi within host plants, such as synergism and competition, are reviewed and the usefulness of serological and molecular methods for studies on these interactions is presented. These quantitative methods will provide helpful information for understanding the ecology of plant pathogenic fungi, such as the dynamics of host plant colonization and species interactions. Key words: quantitative methods, fungal biomass, ELISA, PCR, fungal colonization, species interaction.

scholarly journals Efficient Fluorescence-Based Localization Technique for Tracking Endophytes Route in Host-Plants Colonization

2021 ◽  
Author(s):  
Christine Andeme Ondzighi-Assoume ◽  
Bandana Bhusal ◽  
Adam Traore ◽  
Wilson K Ouma ◽  
Margaret Mmbaga ◽  
...  
Keyword(s):  
Host Plant ◽  
Host Plants ◽  
Plant Pathogens ◽  
Production Systems ◽  
Reporter Genes ◽  
Plant Production ◽  
Plant Colonization ◽  
Bacterial Isolates ◽  
Plant Interactions ◽  
Direct Tracking

Bacterial isolates that enhance plant growth and suppress plant pathogens growth are essential tools for reducing pesticide applications in plant production systems. The objectives of this study were to develop a reliable fluorescence-based technique for labeling bacterial isolates selected as biological control agents (BCAs) to allow their direct tracking in the host-plant interactions, understand the BCA localization within their host plants, and the route of plant colonization. Objectives were achieved by developing competent BCAs transformed with two plasmids, pBSU101 and pANIC-10A, containing reporter genes eGFP and pporRFP, respectively. Our results revealed that the plasmid-mediated transformation efficiencies of antibiotic-resistant competent BCAs identified as PSL, IMC8, and PS were up 84%. Fluorescent BCA-tagged reporter genes were associated with roots and hypocotyls but not with leaves or stems and were confirmed by fluoresence microscopy and PCR analyses in colonized Arabidopsis and sorghum. This fluorescence-based technique's high resolution and reproducibility make it a platform-independent system that allows tracking of BCAs spatially within plant tissues, enabling assessment of the movement and niches of BCAs within colonized plants. Steps for producing and transforming competent fluorescent BCAs, as well as the inoculation of plants with transformed BCAs, localization, and confirmation of fluorescent BCAs through fluorescence imaging and PCR, are provided in this manuscript. This study features host-plant interactions and subsequently biological and physiological mechanisms implicated in these interactions. The maximum time to complete all the steps of this protocol is approximately three months.

Nitric oxide signalling in plant interactions with pathogenic fungi and oomycetes

2020 ◽  
Author(s):  
Tereza Jedelská ◽  
Lenka Luhová ◽  
Marek Petřivalský
Keyword(s):  
Nitric Oxide ◽  
Current Knowledge ◽  
Biotic Interactions ◽  
Decisive Role ◽  
Pathogenic Fungi ◽  
Plant Colonization ◽  
No Production ◽  
Plant Interactions ◽  
Oriented Growth ◽  
Plant Pathogen Interactions

Abstract Nitric oxide (NO) and reactive nitrogen species have emerged as crucial signalling and regulatory molecules across all organisms. In plants, fungi and fungi-like oomycetes, NO is involved in the regulation of multiple processes during their growth, development, reproduction, responses to the external environment and biotic interactions. It has become evident that NO is produced and used as signalling and defence cues by both partners in multiple forms of plant interactions with their microbial counterparts, ranging from symbiotic to pathogenic modes. This review summarizes current knowledge on NO role in plant-pathogen interactions, focused on biotrophic, necrotrophic and hemibiotrophic fungi and oomycetes. Actual advances and gaps in the identification of NO sources and fate in plant and pathogen cells are discussed. We review the decisive role of time- and site-specific NO production in germination, oriented growth and active penetration of filamentous pathogens to the host tissues, as well in pathogen recognition, and defence activation in plants. Distinct functions of NO are highlighted on diverse interactions of host plants with fungal and oomycete pathogens of different lifestyles, where NO in interplay with reactive oxygen species govern successful plant colonization, cell death and resistance establishment.

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

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.

scholarly journals Double Gamers—Can Modified Natural Regulators of Higher Plants Act as Antagonists against Phytopathogens? The Case of Jasmonic Acid Derivatives

2020 ◽  
Vol 21 (22) ◽  
pp. 8681
Author(s):  
Nicolò Orsoni ◽  
Francesca Degola ◽  
Luca Nerva ◽  
Franco Bisceglie ◽  
Giorgio Spadola ◽  
...  
Keyword(s):  
Jasmonic Acid ◽  
Plant Pathogens ◽  
Higher Plants ◽  
Fungal Growth ◽  
Pathogenic Fungi ◽  
Inhibitory Effect ◽  
Fungal Species ◽  
Phytopathogenic Fungi ◽  
Phaeomoniella Chlamydospora ◽  
Horticultural Crops

As key players in biotic stress response of plants, jasmonic acid (JA) and its derivatives cover a specific and prominent role in pathogens-mediated signaling and hence are promising candidates for a sustainable management of phytopathogenic fungi. Recently, JA directed antimicrobial effects on plant pathogens has been suggested, supporting the theory of oxylipins as double gamers in plant-pathogen interaction. Based on these premises, six derivatives (dihydrojasmone and cis-jasmone, two thiosemicarbazonic derivatives and their corresponding complexes with copper) have been evaluated against 13 fungal species affecting various economically important herbaceous and woody crops, such as cereals, grapes and horticultural crops: Phaeoacremonium minimum, Neofusicoccum parvum, Phaeomoniella chlamydospora, Fomitiporia mediterranea, Fusarium poae, F. culmorum, F. graminearum, F. oxysporum f. sp. lactucae,F. sporotrichioides, Aspergillus flavus, Rhizoctonia solani,Sclerotinia spp. and Verticillium dahliae. The biological activity of these compounds was assessed in terms of growth inhibition and, for the two mycotoxigenic species A. flavus and F. sporotrichioides, also in terms of toxin containment. As expected, the inhibitory effect of molecules greatly varied amongst both genera and species; cis-jasmone thiosemicarbazone in particular has shown the wider range of effectiveness. However, our results show that thiosemicarbazones derivatives are more effective than the parent ketones in limiting fungal growth and mycotoxins production, supporting possible applications for the control of pathogenic fungi.

scholarly journals Insect herbivory facilitates the establishment of an invasive plant pathogen

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Martin M. Gossner ◽  
Ludwig Beenken ◽  
Kirstin Arend ◽  
Dominik Begerow ◽  
Derek Peršoh
Keyword(s):  
Invasive Plant ◽  
Pathogenic Fungus ◽  
Feeding Activity ◽  
Insect Herbivory ◽  
Forest Health ◽  
Mechanical Damage ◽  
Pathogenic Fungi ◽  
Fungal Colonization ◽  
Feeding Damage ◽  
The Impact

AbstractPlants can be severely affected by insect herbivores and phytopathogenic fungi, but interactions between these plant antagonists are poorly understood. We analysed the impact of feeding damage by the abundant herbivore Orchestes fagi on infection rates of beech (Fagus sylvatica) leaves with Petrakia liobae, an invasive plant pathogenic fungus. The fungus was not detected in hibernating beetles, indicating that O. fagi does not serve as vector for P. liobae, at least not between growing seasons. Abundance of the fungus in beech leaves increased with feeding damage of the beetle and this relationship was stronger for sun-exposed than for shaded leaves. A laboratory experiment revealed sun-exposed leaves to have thicker cell walls and to be more resistant to pathogen infection than shaded leaves. Mechanical damage significantly increased frequency and size of necroses in the sun, but not in shade leaves. Our findings indicate that feeding damage of adult beetles provides entry ports for fungal colonization by removal of physical barriers and thus promotes infection success by pathogenic fungi. Feeding activity by larvae probably provides additional nutrient sources or eases access to substrates for the necrotrophic fungus. Our study exemplifies that invasive pathogens may benefit from herbivore activity, which may challenge forest health in light of climate change.

Multifaceted Impacts of Bacteriophages in the Plant Microbiome

2018 ◽  
Vol 56 (1) ◽  
pp. 361-380 ◽  
Author(s):  
Britt Koskella ◽  
Tiffany B. Taylor
Keyword(s):  
Host Plant ◽  
Future Study ◽  
Plant Pathogens ◽  
Ecological Interactions ◽  
Selection Pressures ◽  
Bacterial Populations ◽  
Associated Bacteria ◽  
Open Questions ◽  
Microbe Interactions ◽  
Plant Microbiome

Plant-associated bacteria face multiple selection pressures within their environments and have evolved countless adaptations that both depend on and shape bacterial phenotype and their interaction with plant hosts. Explaining bacterial adaptation and evolution therefore requires considering each of these forces independently as well as their interactions. In this review, we examine how bacteriophage viruses (phages) can alter the ecology and evolution of plant-associated bacterial populations and communities. This includes influencing a bacterial population's response to both abiotic and biotic selection pressures and altering ecological interactions within the microbiome and between the bacteria and host plant. We outline specific ways in which phages can alter bacterial phenotype and discuss when and how this might impact plant-microbe interactions, including for plant pathogens. Finally, we highlight key open questions in phage-bacteria-plant research and offer suggestions for future study.

scholarly journals Spray-induced gene silencing for disease control is dependent on the efficiency of pathogen RNA uptake

2021 ◽  
Author(s):  
Lulu Qiao ◽  
Chi Lan ◽  
Luca Capriotti ◽  
Audrey Ah-Fong ◽  
Jonatan Nino Sanchez ◽  
...  
Keyword(s):  
Disease Management ◽  
Plant Disease ◽  
Plant Pathogens ◽  
Developmental Stages ◽  
Pathogenic Fungi ◽  
Cell Types ◽  
Uptake Efficiency ◽  
Fungal Plant Pathogens ◽  
Plant Disease Management ◽  
Fungal Genes

AbstractRecent discoveries show that fungi can take up environmental RNA, which can then silence fungal genes through environmental RNA interference. This discovery prompted the development of Spray-Induced Gene Silencing (SIGS) for plant disease management. In this study, we aimed to determine the efficacy of SIGS across a variety of eukaryotic microbes. We first examined the efficiency of RNA uptake in multiple pathogenic and non-pathogenic fungi, and an oomycete pathogen. We observed efficient double-stranded RNA (dsRNA) uptake in the fungal plant pathogens Botrytis cinerea, Sclerotinia sclerotiorum, Rhizoctonia solani, Aspergillus niger, and Verticillium dahliae, but no uptake in Colletotrichum gloeosporioides, and weak uptake in a beneficial fungus, Trichoderma virens. For the oomycete plant pathogen, Phytophthora infestans, RNA uptake was limited, and varied across different cell types and developmental stages. Topical application of dsRNA targeting virulence-related genes in the pathogens with high RNA uptake efficiency significantly inhibited plant disease symptoms, whereas the application of dsRNA in pathogens with low RNA uptake efficiency did not suppress infection. Our results have revealed that dsRNA uptake efficiencies vary across eukaryotic microbe species and cell types. The success of SIGS for plant disease management can largely be determined by the pathogen RNA uptake efficiency.

scholarly journals Cooperation of two opposite flagella allows high-speed swimming and active turning in zoospores

2021 ◽  
Author(s):  
Quang D. Tran ◽  
Eric Galiana ◽  
Philippe Thomen ◽  
Céline Cohen ◽  
François Orange ◽  
...  
Keyword(s):  
Host Plant ◽  
High Speed ◽  
Plant Pathogens ◽  
Plant Diseases ◽  
Active Process ◽  
Motility Pattern ◽  
Anterior Flagellum ◽  
Active Turning ◽  
Posterior Flagellum ◽  
Run And Tumble

Phytophthora species cause diseases in a large variety of plants and represent a serious agricultural threat, leading, every year, to multibillion dollar losses. Infection occurs when these biflagellated zoospores move across the soil at their characteristic high speed and reach the roots of a host plant. Despite the relevance of zoospore spreading in the epidemics of plant diseases, it is not known how these zoospores swim and steer with two opposite beating flagella. Here, combining experiments and modeling, we show how these two flagella contribute to generate thrust when beating together, and identify the mastigonemes-attached anterior flagellum as the main source of thrust. Furthermore, we find that steering involves a complex active process, in which the posterior flagellum is stopped, while the anterior flagellum keeps on beating, as the zoospore reorients its body. Our study is a fundamental step towards a better understanding of the spreading of plant pathogens’ motile forms, and shows that the motility pattern of these biflagellated zoospores represents a distinct eukaryotic version of the celebrated “run-and-tumble” motility class exhibited by peritrichous bacteria.

scholarly journals Antimicrobial activity of essential oils on pathogenic fungi

2017 ◽  
Vol 9 (3) ◽  
Author(s):  
Daniele Aparecida do Couto ◽  
Felipe Da Silva Dias ◽  
Mírian Lobo Sáber
Keyword(s):  
Essential Oils ◽  
Eucalyptus Globulus ◽  
Plant Pathogens ◽  
Pathogenic Fungi ◽  
Human Beings ◽  
Cymbopogon Winterianus ◽  
Callistemon Viminalis ◽  
Pathogenic Agents ◽  
Citronella Grass ◽  
Mycelial Development

Since the induction of chemical defensives in agriculture, human beings have suffered from our own actions, caused by the indiscriminate and abusive use of those substances; therefore, researches have been motivated to look for alternative ways, aiming to use plant inputs to control pathogenic agents in agriculture. As the essential oils from the species Eucalyptus globulus (eucalyptus), Callistemon viminalis (weeping bottlebrush), Cymbopogon winterianus (citronella grass) and Tetradeniariparia (misty plume bush) have proved effectiveness and an immense applicability, this research studied the use of those essential oils, aiming the effectiveness against plant pathogens. The plants were collected from Universidade do Vale do Sapucaí, Pouso Alegre (MG). The fungi’s samples belong to the mycology collection from the institution and the tests were based on the mycelial development comparison of the control fungi on the dishes with essential oils. Notice that the inhibition caused by the oils over fungi’s mycelial developing and the analysis of the data have been made through Turkey’s statistic. From the data analyzed, it was possible to realize that the citronella’s grass essential oil was efficient to control the mycelial development of fungi analyzed, followed by, in order of efficiency, the eucalyptus oil, the weeping bottlebrush oil and the misty plume bush oil.

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