Cell biology of early events in the plant resistance response to infection by pathogenic fungi

1995 ◽  
Vol 73 (S1) ◽  
pp. 418-425 ◽  
Author(s):  
I. Kobayashi ◽  
L. J. Murdoch ◽  
A. R. Hardham ◽  
H. Kunoh
Keyword(s):  
Plant Resistance ◽  
Cell Biology ◽  
Fungal Pathogens ◽  
Plant Defence ◽  
Pathogenic Fungi ◽  
Callose Deposition ◽  
Resistance Response ◽  
New Genes ◽  
Host Cell Wall ◽  
Plant Cytoskeleton

In addition to passive (or constitutive) defence mechanisms, plants have evolved a range of active (or inducible) responses that occur rapidly on infection with an incompatible (avirulent) pathogen and that are thought to play a major role in the expression of resistance. These defence reactions are only induced if the plant possesses the ability to recognize and respond to the pathogen. Signal reception by the host must initiate a cascade of events that lead to the expression of resistance. Some resistance responses, such as callose deposition, do not require the expression of new genes. Many responses, for example the synthesis and secretion of toxic compounds or molecules that enhance the strength of physical barriers, result from changes in the pattern of gene transcription. Other defence phenomena include hypersensitive cell collapse, intercellular signalling, and the induction of defence gene transcripts in surrounding cells. Changes in cell biochemistry and physiology are accompanied by characteristic structural modifications in the infected cells, such as the redeployment of selected organelles and dramatic modifications of the host cell wall. Recent evidence indicates that microtubules and microfilaments of the plant cytoskeleton facilitate the rapid localization of these and other plant defence responses to the region of infection. Key words: plant resistance, plant cytoskeleton, microtubules, microfilaments, fungal pathogens, polarity of defence response.

SOYBEAN AND FLAX SELECTION METHODS

1970 ◽  
pp. 19-23
Author(s):  
V. М. Lukomets ◽  
S. V. Zelentsov
Keyword(s):  
High Resistance ◽  
Fungal Pathogens ◽  
Selection Process ◽  
Pathogenic Fungi ◽  
Cultivated Plants ◽  
Practical Implementation ◽  
Physiological Basis ◽  
Oil Crops ◽  
Soybean Genotypes ◽  
Genetically Determined

To improve the effectiveness of the soybeans and oil flax breeding, research to improve existing and develop new breeding methods are conducting in all-Russia Research institute of Oil Crops (Krasnodar). One of the improved methods for the soybean breeding, based on the use of sources of complexes of compensatory genes, is the CCG technology, which allows to create varieties with an increased yield of a heterotic level transmitted along the progeny for the entire life cycle of the variety. For the purpose of non-transgenic production of new traits, a theory of polyploid recombination of the genome (TPR) was formulated, which models the mechanism of the natural formation of polymorphism in the centers of origin of cultivated plants. On the basis of this theory, a method of breeding (TPR-technology) has been developed, which makes it possible to obtain recombinant reploids of soybeans and oil flax with an extended spectrum of traits. Of these reploids, the soybean lines with increased sucking force of the roots, providing high drought resistance, were distinguished; cold-resistant soybean lines, which stand in the phase of shoots of freezing to minus 5 °С; lines of oil flax with complete resistance to flax sickness of soil and high resistance to Fusarium; winter-hardy flax lines that withstand winter frosts down to minus 20–23 °С and ripen one and a half months earlier than spring sowings. Another original developed method is the ODCS-technology for isolating and selecting soybean genotypes with high resistance to fungal pathogens. The physiological basis of ODCS-technology is the blocking of osmotic nutrition of pathogenic fungi due to genetically determined increased osmotic pressure in the tissues of host plants. The practical implementation of CCG-, TPR- and ODKS-technologies in the selection process, allowed to create a whole series of soybean and oil flax varieties with improved or new traits.

scholarly journals Mitotic Recombination and Adaptive Genomic Changes in Human Pathogenic Fungi

Genes ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 901 ◽  
Author(s):  
Asiya Gusa ◽  
Sue Jinks-Robertson
Keyword(s):  
Fungal Pathogens ◽  
Repetitive Sequences ◽  
Pathogenic Fungi ◽  
Genetic Alterations ◽  
Fungal Species ◽  
Chronic Infections ◽  
Yeast Saccharomyces Cerevisiae ◽  
Genomic Changes ◽  
Break Site ◽  
Repair Mechanisms

Genome rearrangements and ploidy alterations are important for adaptive change in the pathogenic fungal species Candida and Cryptococcus, which propagate primarily through clonal, asexual reproduction. These changes can occur during mitotic growth and lead to enhanced virulence, drug resistance, and persistence in chronic infections. Examples of microevolution during the course of infection were described in both human infections and mouse models. Recent discoveries defining the role of sexual, parasexual, and unisexual cycles in the evolution of these pathogenic fungi further expanded our understanding of the diversity found in and between species. During mitotic growth, damage to DNA in the form of double-strand breaks (DSBs) is repaired, and genome integrity is restored by the homologous recombination and non-homologous end-joining pathways. In addition to faithful repair, these pathways can introduce minor sequence alterations at the break site or lead to more extensive genetic alterations that include loss of heterozygosity, inversions, duplications, deletions, and translocations. In particular, the prevalence of repetitive sequences in fungal genomes provides opportunities for structural rearrangements to be generated by non-allelic (ectopic) recombination. In this review, we describe DSB repair mechanisms and the types of resulting genome alterations that were documented in the model yeast Saccharomyces cerevisiae. The relevance of similar recombination events to stress- and drug-related adaptations and in generating species diversity are discussed for the human fungal pathogens Candida albicans and Cryptococcus neoformans.

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 Isolation and Characterization of Root-Associated Bacterial Endophytes and Their Biocontrol Potential against Major Fungal Phytopathogens of Rice (Oryza sativa L.)

Pathogens ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 172
Author(s):  
Maqsood Ahmed Khaskheli ◽  
Lijuan Wu ◽  
Guoqing Chen ◽  
Long Chen ◽  
Sajid Hussain ◽  
...  
Keyword(s):  
Oryza Sativa ◽  
Fungal Pathogens ◽  
Oryza Sativa L ◽  
Defense Responses ◽  
Growth And Yield ◽  
Bacterial Endophytes ◽  
16S Rrna Sequence ◽  
Resistance Response ◽  
Isolation And Characterization ◽  
Fungal Phytopathogens

Rice (Oryza sativa L.) is a major cereal food crop worldwide, and its growth and yield are affected by several fungal phytopathogens, including Magnaporthe oryzae, Fusarium graminearum, F. moniliforme, and Rhizoctonia solani. In the present study, we have isolated and characterized root-associated bacterial endophytes that have antifungal activities against rice fungal phytopathogens. A total of 122 root-associated bacterial endophytes, belonging to six genera (Bacillus, Fictibacillus, Lysinibacillus, Paenibacillus, Cupriavidus, and Microbacterium) and 22 species were isolated from three rice cultivars. Furthermore, the 16S rRNA sequence-based phylogeny results revealed that Bacillus was the most dominant bacterial genera, and that there were 15 different species among the isolates. Moreover, 71 root-associated endophytes showed antagonistic effects against four major fungal phytopathogens, including M. oryzae, F. graminearum, F. moniliforme, and R. solani. Additionally, the biochemical, physiological, and PCR amplification results of the antibiotic-related genes further supported the endophytes as potential biocontrolling agents against the rice fungal pathogens. Consequently, the findings in this study suggested that the isolated bacterial endophytes might have beneficial roles in rice defense responses, including several bioactive compound syntheses. The outcomes of this study advocate the use of natural endophytes as an alternative strategy towards the rice resistance response.

Transgenic expression of gallerimycin, a novel antifungal insect defensin from the greater wax moth Galleria mellonella, confers resistance to pathogenic fungi in tobacco

2006 ◽  
Vol 387 (5) ◽  
pp. 549-557 ◽  
Author(s):  
Gregor Langen ◽  
Jafargholi Imani ◽  
Boran Altincicek ◽  
Gernot Kieseritzky ◽  
Karl-Heinz Kogel ◽  
...  
Keyword(s):  
Transgenic Tobacco ◽  
Fungal Pathogens ◽  
Galleria Mellonella ◽  
Ectopic Expression ◽  
Pathogenic Fungi ◽  
Transgenic Expression ◽  
Greater Wax Moth ◽  
Insect Defensin ◽  
Wax Moth

Abstract A cDNA encoding gallerimycin, a novel antifungal peptide from the greater wax moth Galleria mellonella, was isolated from a cDNA library of genes expressed during innate immune response in the caterpillars. Upon ectopic expression of gallerimycin in tobacco, using Agrobacterium tumefaciens as a vector, gallerimycin conferred resistance to the fungal pathogens Erysiphe cichoracearum and Sclerotinia minor. Quantification of gallerimycin mRNA in transgenic tobacco by real-time PCR confirmed transgenic expression under control of the inducible mannopine synthase promoter. Leaf sap and intercellular washing fluid from transgenic tobacco inhibited in vitro germination and growth of the fungal pathogens, demonstrating that gallerimycin is secreted into intercellular spaces. The feasibility of the use of gallerimycin to counteract fungal diseases in crop plants is discussed.

Elicitins' Oligomeric States Affect The Hypersensitive Response And Resistance In Tobacco

2021 ◽  
Author(s):  
Martin Solanský ◽  
Kamil Mikulášek ◽  
Martina Zapletalová ◽  
Marek Petřivalský ◽  
Annick Chiltz ◽  
...  
Keyword(s):  
Hypersensitive Response ◽  
Early Recognition ◽  
Tobacco Plant ◽  
Plant Defence ◽  
Microbial Pathogens ◽  
Plant Responses ◽  
Resistance Response ◽  
Basal Resistance ◽  
Pathogenesis Related Protein ◽  
Fast Activation

Abstract Successful plant defence against microbial pathogens is based on early recognition and fast activation of inducible responses. Key mechanisms include detection of microbe-associated molecular patterns by membrane-localized Pattern Recognition Receptors that induce a basal resistance response. A well-described model of such responses to pathogens involves interaction between Solanaceae plants with proteinaceous elicitors secreted by oomycetes, called elicitins. It has been hypothesised that elicitins' formation of oligomeric structures could be involved in their recognition and activation of defensive transduction cascades. In tests of this hypothesis reported here, using several approaches, we observed differences in tobacco plant responses induced by the elicitin β-cryptogein (β-CRY) and its homodimer (β-CRY DIM). We also found that the C-terminal domain of elicitins of other ELI clades plays a significant role in stabilization of their oligomeric structure and restraint in the cell wall. In addition, covalently crosslinking β-CRY DIM impaired formation of signalling complexes, thereby reducing its capacity to elicit the hypersensitive response and resistance in the host plant, with no significant changes in pathogenesis-related protein expression. The results illuminate the poorly understood role of elicitins' oligomeric structures in oomycetes' interaction with plants, by revealing details of effects of β-CRY dimerization on tobacco plants' recognition and defence responses.

Sordarins: In Vitro Activities of New Antifungal Derivatives against Pathogenic Yeasts, Pneumocystis carinii, and Filamentous Fungi

1998 ◽  
Vol 42 (11) ◽  
pp. 2863-2869 ◽  
Author(s):  
E. Herreros ◽  
C. M. Martinez ◽  
M. J. Almela ◽  
M. S. Marriott ◽  
F. Gomez De Las Heras ◽  
...  
Keyword(s):  
Cryptococcus Neoformans ◽  
Filamentous Fungi ◽  
Fungal Pathogens ◽  
Pneumocystis Carinii ◽  
Pathogenic Fungi ◽  
Pseudallescheria Boydii ◽  
Absidia Corymbifera ◽  
Wide Range ◽  
Blastoschizomyces Capitatus

ABSTRACT GM 193663, GM 211676, GM 222712, and GM 237354 are new semisynthetic derivatives of the sordarin class. The in vitro antifungal activities of GM 193663, GM 211676, GM 222712, and GM 237354 against 111 clinical yeast isolates of Candida albicans,Candida kefyr, Candida glabrata, Candida parapsilosis, Candida krusei, and Cryptococcus neoformans were compared. The in vitro activities of some of these compounds against Pneumocystis carinii, 20 isolates each of Aspergillus fumigatus and Aspergillus flavus, and 30 isolates of emerging less-common mold pathogens and dermatophytes were also compared. The MICs of GM 193663, GM 211676, GM 222712, and GM 237354 at which 90% of the isolates were inhibited (MIC90s) were 0.03, 0.03, 0.004, and 0.015 μg/ml, respectively, for C. albicans, including strains with decreased susceptibility to fluconazole; 0.5, 0.5, 0.06, and 0.12 μg/ml, respectively, for C. tropicalis; and 0.004, 0.015, 0.008, and 0.03 μg/ml, respectively, forC. kefyr. GM 222712 and GM 237354 were the most active compounds against C. glabrata, C. parapsilosis, and Cryptococcus neoformans. AgainstC. glabrata and C. parapsilosis, the MIC90s of GM 222712 and GM 237354 were 0.5 and 4 μg/ml and 1 and 16 μg/ml, respectively. The MIC90s of GM 222712 and GM 237354 againstCryptococcus neoformans were 0.5 and 0.25 μg/ml, respectively. GM 193663, GM 211676, GM 222712, and GM 237354 were extremely active against P. carinii. The efficacies of sordarin derivatives against this organism were determined by measuring the inhibition of the uptake and incorporation of radiolabelled methionine into newly synthesized proteins. All compounds tested showed 50% inhibitory concentrations of <0.008 μg/ml. Against A. flavus and A. fumigatus, the MIC90s of GM 222712 and GM 237354 were 1 and 32 μg/ml and 32 and >64 μg/ml, respectively. In addition, GM 237354 was tested against the most important emerging fungal pathogens which affect immunocompromised patients. Cladosporium carrioni, Pseudallescheria boydii, and the yeast-like fungi Blastoschizomyces capitatus and Geotrichum clavatum were the most susceptible of the fungi to GM 237354, with MICs ranging from ≤0.25 to 2 μg/ml. The MICs of GM 237354 against Trichosporon beigelii and the zygomycetesAbsidia corymbifera, Cunninghamella bertholletiae, and Rhizopus arrhizus ranged from ≤0.25 to 8 μg/ml. Against dermatophytes, GM 237354 MICs were ≥2 μg/ml. In summary, we concluded that some sordarin derivatives, such as GM 222712 and GM 237354, showed excellent in vitro activities against a wide range of pathogenic fungi, includingCandida spp., Cryptococcus neoformans, P. carinii, and some filamentous fungi and emerging invasive fungal pathogens.

scholarly journals Chitinases—Potential Candidates for Enhanced Plant Resistance towards Fungal Pathogens

Agriculture ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 88 ◽  
Author(s):  
Manish Kumar ◽  
Amandeep Brar ◽  
Monika Yadav ◽  
Aakash Chawade ◽  
V. Vivekanand ◽  
...  
Keyword(s):  
Plant Resistance ◽  
Fungal Pathogens

scholarly journals Morphological and Molecular Diversity of Ginger (Zingiber officinale Roscoe) Pathogenic Fungi in Chilga District, North Gondar, Ethiopia

2022 ◽  
Vol 2 ◽  
Author(s):  
Sefinew Tilahun ◽  
Marye Alemu ◽  
Mesfin Tsegaw ◽  
Nega Berhane
Keyword(s):  
Causative Agent ◽  
Fungal Pathogens ◽  
Pathogenic Fungus ◽  
Management Strategies ◽  
Infected Plant ◽  
Pathogenic Fungi ◽  
Zingiber Officinale ◽  
Morphological Characterization ◽  
Molecular Techniques ◽  
Diseased Plant

Ginger diseases caused by fungal pathogens have become one of the most serious problems causing reduced production around the world. It has also caused a major problem among farmers in different parts of Ethiopia resulting in a huge decline in rhizome yield. However, the exact causative agents of this disease have not been identified in the state. Although there are few studies related to pathogenic fungus identification, molecular level identification of fungal pathogen was not done in the area. Therefore, this study was undertaken to isolate and characterized the fungal causative agent of ginger disease from the diseased plant and the soil samples collected around the diseased plant from Chilga district, Gondar, Ethiopia. Samples from infected ginger plants and the soil around the infected plant were collected. Culturing and purification of isolates were made using Potato Dextrose Agar supplemented with antibacterial agent chloramphenicol. The morphological characterization was done by structural identification of the isolates under the microscope using lactophenol cotton blue stains. Isolated fungi were cultured and molecular identification was done using an internal transcribed spacer (ITS) of ribosomal DNA (rDNA). A total of 15 fungal morphotypes including 11 Aspergillus spp. (73.3%), 2 Penicillium spp. (13.3%), and single uncultured fungus clone S23 were isolated from the samples representing all the plant organs and the soil. Aspergillus spp. (73.3%) was the most common and seems to be the major causative agent. To the best of our knowledge, this is the first report of ginger pathogenic fungi in Ethiopia identified using ITS rDNA molecular techniques. This study will lay foundation for the development of management strategies for fungal diseases infecting ginger.

scholarly journals A comparative evaluation of Kumaun Himalayan Gymnosperms for their Antifungal potential against plant pathogenic fungi

2018 ◽  
Vol 7 (3) ◽  
pp. 230-241
Author(s):  
Savita Joshi ◽  
◽  
Parikshit Kumar ◽  
Prabha Pant ◽  
SC Sati ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Fungal Pathogens ◽  
Ethanol Extract ◽  
Pathogenic Fungi ◽  
Total Activity ◽  
Maximum Activity ◽  
Diffusion Method ◽  
Phytochemical Analysis ◽  
Cedrus Deodara ◽  
Araucaria Cunninghamii

Fungicidal activity of 10 ethnobotanically known Kumaun Himalayan gymnospermous plants namely Araucaria cunninghamii, Biota orientalis, Cedrus deodara, Cephalotaxus griffithi, Cryptomeria japonica Cupressus torulosa, Ginkgo biloba, Juniperus communis, Picea smithiana and Pinus wallichiana were tested against six plant disease causing fungal pathogens by agar well-diffusion method. Forty extracts of these gymnospermic leaves in different organic solvents (methanol, ethanol, chloroform and hexane) were studied by performing the 160 sets of experiments. The MIC values of each extract (where % inhibition ≥ 40%) were also determined. All the plant extracts exhibited strong antifungal activity. Results indicated that all leaves extracts of C. griffithi and G. biloba were found most effective among the tested plants extracts. Hexane extract of C. griffithi was showed highest inhibitory activity against C. falcatum (72%; MIC, 7.81µg/ml) and T. indica (70%; MIC, 15.62µg/ml). On the other hand, ethanol extract of G. biloba also showed remarkable activity against P. oryzae (66% with MIC, 7.81g/ml). While P. wallichiana leave extracts were found less active among the studied plants against all the tested fungal strains. The chloroform extracts were found the most effective against all the tested fungi (10% to 60%), followed by ethanol extract (30-50%), methanol extract (20-40%), while in hexane extracts ranged 10-30% only. The extracts of C. griffithi exhibited superior Relative Antifungal Activity (RAA, 20%), followed by G. biloba and A. cunninghamii (RAA, 19 and 12%, respectively). All data were also analyzed for determination of total activity of plant for each studied species of gymnosperm. C. griffithi had maximum activity i.e. 71 % followed by G. biloba (54%) and A. cunninghamii (33%). C. torulosa showed the least total activity and RAA i.e. 8% and 3%, respectively. All the plant species assayed possess definite antifungal properties and suggested for phytochemical analysis to identify the active principles responsible for their antifungal activity

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