scholarly journals Arabidopsis phytochelatin synthase 1, but not phytochelatin synthesis, functions in extracellular defense against multiple fungal pathogens

2019 ◽  
Author(s):  
Kian Hematy ◽  
Melisa Lim ◽  
Candice Cherk ◽  
Paweł Bednarek ◽  
Mariola Piślewska-Bednarek ◽  
...  

ABSTRACTPhytochelatin synthase (PCS) is a key component of heavy metal detoxification in plants. PCS catalyzes both the synthesis of the peptide phytochelatin from glutathione as well as the degradation of glutathione conjugates via peptidase activity. Here, we describe a hitherto uncharacterized role for PCS in disease resistance against plant pathogenic fungi. The pen4 mutant, which is allelic to cadmium insensitive 1 (cad1/pcs1) mutants, was recovered from a screen for Arabidopsis mutants with reduced resistance to the non-adapted barley fungal pathogen, Blumeria graminis f. sp. hordei. PCS1, which is found in the cytoplasm of cells of healthy plants, translocates upon pathogen attack and colocalizes with the PEN2 myrosinase on the surface of immobilized mitochondria. pcs1 and pen2 mutant plants exhibit a similar metabolic defect in the accumulation of pathogen-inducible indole glucosinolate-derived compounds, suggesting that PEN2 and PCS1 act in the same metabolic pathway. The function of PCS1 in this pathway is independent of phytochelatin synthesis and deglycination of glutathione conjugates, as catalytic-site mutants of PCS1 are still functional in indole glucosinolate metabolism. In uncovering a previously unknown function for PCS1, we reveal this enzyme to be a moonlighting protein important for plant responses to both biotic and abiotic stresses.

EUGENIA ◽  
2011 ◽  
Vol 17 (3) ◽  
Author(s):  
Emmy Senewe ◽  
Guntur Manengkey

ABSTRACT Leptocorisa oratorius is one major pest of rice in North Sulawesi. Hence, it is necessary to control the pest. The research objective was to identify and to test pathogenicity of local  entomopathogen fungi which infected  Leptocorisa oratorius. The pathogens were collected through sampling of L. oratorius which had been infected by the fungi in the field. The pathogenic fungi was isolated using PDA medium, identified followed by inoculation for pathogenecity test.  During several sampling pest, it was found that  L. oratorius was attacked by fungal pathogens in the field. The identification revelead that the fungal pathogens were Beauveria sp and Fusarium sp. Both the fungal pathogen produced white mycelium and could only be distinguished using microscope in the laboratory. Result of pathogenicity tests showed that the two fungal pathogens caused different mortality of the L. oratorius. Mortality of  L. oratorius caused by pathogenic fungus Beauveria sp was  30.3% . Whereas, mortality of  L. oratorius caused by Fusarium sp was only 3.33%. Keywords : pathogenic fungi, entomopathogen, pathogenicity tests, L. oratorius


Author(s):  
S. M. Yahaya ◽  
A. B. Kamalu ◽  
M. U. Ali ◽  
M. Lawan ◽  
Y. S. Ajingi ◽  
...  

This research was conducted to determine the fungal pathogens responsible for post harvest losses of pineapple sold at Wudil and Yen lemo markets.  Two samples of pineapples were purchased twice a week from both Wudil and Yanlemo markets for four months. The samples were investigated for the presence of fungal pathogen using standard microbiological methods. The methods involve mounting small portion of pineapple in the plate containing Potato dextrose agar to isolate the fungi. Three fungal pathogens belonging to Aspergillus species were isolated, and Aspergillus niger had the highest frequency of occurrence of (50%). Followed by A. flavus with (27%). The A. fumigatus had the lowest frequency of occurrence of (23%). The differences between the fungal isolates recorded were significantly different (P<0.05) between the two markets, where higher fungal isolates were recorded at Yanlemo market 159 (40.6%) and Wudil 38 (9.71%). The study showed that the post harvest losses of pine apple in the two markets are attributed to fungal infection. Therefore, safe guarding the two markets from debris and dumps of rotten fruits and vegetable may assist in reducing fungal inoculums in the two markets.


Author(s):  
V. М. Lukomets ◽  
S. V. Zelentsov

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.


Genes ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 901 ◽  
Author(s):  
Asiya Gusa ◽  
Sue Jinks-Robertson

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.


2021 ◽  
Vol 7 (2) ◽  
pp. 86
Author(s):  
Bilal Ökmen ◽  
Daniela Schwammbach ◽  
Guus Bakkeren ◽  
Ulla Neumann ◽  
Gunther Doehlemann

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.


2006 ◽  
Vol 387 (5) ◽  
pp. 549-557 ◽  
Author(s):  
Gregor Langen ◽  
Jafargholi Imani ◽  
Boran Altincicek ◽  
Gernot Kieseritzky ◽  
Karl-Heinz Kogel ◽  
...  

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.


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 ◽  
...  

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.


2016 ◽  
Vol 1 (1) ◽  
pp. 69-74 ◽  
Author(s):  
Sofiane El-Kirat-Chatel ◽  
Yves F. Dufrêne

We establish atomic force microscopy as a new nanoscopy platform for quantifying the forces between fungal pathogens and immune cells.


mBio ◽  
2018 ◽  
Vol 9 (5) ◽  
Author(s):  
Robin C. May ◽  
Arturo Casadevall

ABSTRACT For pathogenic microbes to survive ingestion by macrophages, they must subvert powerful microbicidal mechanisms within the phagolysosome. After ingestion, Candida albicans undergoes a morphological transition producing hyphae, while the surrounding phagosome exhibits a loss of phagosomal acidity. However, how these two events are related has remained enigmatic. Now Westman et al. (mBio 9:e01226-18, 2018, https://doi.org/10.1128/mBio.01226-18) report that phagosomal neutralization results from disruption of phagosomal membrane integrity by the enlarging hyphae, directly implicating the morphological transition in physical damage that promotes intracellular survival. The C. albicans intracellular strategy shows parallels with another fungal pathogen, Cryptococcus neoformans, where a morphological changed involving capsular enlargement intracellularly is associated with loss of membrane integrity and death of the host cell. These similarities among distantly related pathogenic fungi suggest that morphological transitions that are common in fungi directly affect the outcome of the fungal cell-macrophage interaction. For this class of organisms, form determines fate in the intracellular environment.


2022 ◽  
Vol 2 ◽  
Author(s):  
Sefinew Tilahun ◽  
Marye Alemu ◽  
Mesfin Tsegaw ◽  
Nega Berhane

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.


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