scholarly journals The effect of acquired triazole resistance on abiotic stress tolerance and virulence in Candida auris micro evolved strains

2021 ◽  
Vol 3 (12) ◽  
Author(s):  
Flora Bohner ◽  
Csaba Papp ◽  
Mónika Varga ◽  
András Szekeres ◽  
Renáta Tóth ◽  
...  
Keyword(s):  
Abiotic Stress ◽  
Stress Tolerance ◽  
Abiotic Stress Tolerance ◽  
Antifungal Susceptibility ◽  
Antifungal Resistance ◽  
Cross Resistance ◽  
Fungal Burden ◽  
Mutant Strains ◽  
The Impact

Recently, C. auris become one of the most prominent members of the genus Candida. Since its occurrence, several C. auris outbreaks have been reported worldwide. These outbreaks were associated with isolates displaying decreased susceptibility towards fluconazole, the first-line agent for prophylaxis. Fluconazole is the most frequently used antifungal drug to treat bloodstream Candida infections. The physiological effects of acquired antifungal resistance was investigated in this species using fluconazole, posaconazole and voriconazole resistant mutant strains generated by the in vitro microevolution method. Alterations in antifungal susceptibility and cross resistance were determined by the microdilution method, utilizing azoles (fluconazole, voriconazole, posaconazole), echinocandins (caspofungin, micafungin, anidulafungin) and a polyene (amphotericin B). Changes in the abiotic stress tolerance was examined by spotting assay, using osmotic stressors, cell wall perturbants and a membrane detergent. To evaluate the impact of the acquired resistance on sterol biosynthesis, ergosterol composition of all generated mutant strains were examined. A potential relationship between virulence and acquired antifungal resistance was also studied both in vitro and in vivo. Phagocytosis of the generated strains by J774.2 mouse macrophage-like cells was measured and analyzed by flow cytometry. In the murine infection model fungal burden of the triazole evolved strains was determined in spleen, kidney, liver and brain and compared to the fungal burden associated with the initial azole susceptible strain. Significant differences in virulence of the initial and the generated strains was observed suggesting a potential connection between the virulence and antifungal susceptibility of the emerging fungal pathogen, C. auris.

In vitro induced tetraploid of Dendranthema nankingense (Nakai) Tzvel. shows an improved level of abiotic stress tolerance

2011 ◽  
Vol 127 (3) ◽  
pp. 411-419 ◽  
Author(s):  
Siyu Liu ◽  
Sumei Chen ◽  
Yu Chen ◽  
Zhiyong Guan ◽  
Dongmei Yin ◽  
...  
Keyword(s):  
Abiotic Stress ◽  
Stress Tolerance ◽  
Abiotic Stress Tolerance

High doses of melatonin confer abiotic stress tolerance to phytopathogenic fungi grown in vitro

2020 ◽  
Vol 3 (2) ◽  
pp. 187-193
Author(s):  
Andrew Pio Madigan ◽  
Christopher Harris ◽  
Frank Bedon ◽  
Ashley E Franks ◽  
Kim M Plummer
Keyword(s):  
Abiotic Stress ◽  
Stress Tolerance ◽  
Abiotic Stress Tolerance ◽  
Crop Protection ◽  
Fungal Growth ◽  
Phytopathogenic Fungi ◽  
Growth Responses ◽  
Domains Of Life ◽  
High Concentrations

Melatonin is a secondary metabolite produced in all domains of life. Exogenous melatonin triggers defence mechanisms in plants that enhance abiotic stress tolerance. However, knowledge regarding the role of melatonin as a signal or an antioxidant in microbes is lacking. We investigated the in vitro growth responses of three phytopathogenic fungi, Sclerotinia sclerotiorum, Botrytis cinerea and Fusarium oxysporum f.sp. vasinfectum, to abiotic stress (2.5% ethanol with/without cold priming) under varying concentrations of melatonin. Melatonin at high concentrations (1000 – 2000 µM) partially restored fungal growth under stress, compared to controls, suggesting a role for melatonin in alleviating the impacts of stress exposure. Understanding how melatonin impacts fungal growth during stress conditions will be important for future applications using melatonin as a tool for crop protection.

scholarly journals Differential expression of genes in response to salinity stress in tree tomato (Solanum betaceum)

2018 ◽  
Vol 3 (2) ◽  
pp. 1-15
Author(s):  
Viviana Jaramillo ◽  
Carlos Vintimilla ◽  
Andrés F. Torres ◽  
Venancio Arahana ◽  
María de Lourdes Torres
Keyword(s):  
Abiotic Stress ◽  
Stress Tolerance ◽  
Salinity Stress ◽  
Differential Display ◽  
Abiotic Stress Tolerance ◽  
Ecological Adaptability ◽  
Differential Display Analysis ◽  
Solanum Betaceum ◽  
Tree Tomato

The Andean “tree tomato” (Solanum betaceum) is an exotic fruit crop endemic to the high Andes, but principally cultivated in Colombia, Peru and Ecuador. The species displays broad agro-ecological adaptability and has proven resilient to different marginality factors, including high soil-salinity. This study presents a preliminary exploration of the genetic mechanisms underlying salinity tolerance in S. betaceum. To this end, we selected two S. betaceum genotypes contrasting in their ability to tolerate high salinity in vitro, and used differential display analysis to compare overall differences in gene expression between salinity-stressed and unstressed (control) plants in both genotypes. Overall, 171 differentially expressed transcripts (DETs) were identified; 30 of which showed homology with candidate genes associated with abiotic stress tolerance in different species. These were ascribed putative roles in stressresponse, photosynthesis, cellular metabolism and cell wall metabolism. Several identified DETs (22 in total) also showed homology to proteins of unknown function. These sequences warrant further research for potentially novel abiotic stress tolerance mechanisms. Despite its inherent limitations, differential display analysis allowed us to identify and validate (via RT-qPCR) 3 salinity-stress induced DETs. Prospectively, expanding our analyses via the validation of additional DETs would likely contribute to the identification of genes which can be used as proxies for a better understanding of the regulatory, metabolic and physiological mechanisms used by S. betaceum to respond and adapt to salinity stress.

scholarly journals Precise editing using CRISPR-Cas9 to explore the contribution of clinically-derived mutations to antifungal resistance in the pathogenic yeast Candida parapsilosis

2021 ◽  
Vol 3 (12) ◽  
Author(s):  
Sophie Hartuis ◽  
Estelle Robert ◽  
Lisa Lombardi ◽  
Geraldine Butler ◽  
Patrice Le Pape ◽  
...  
Keyword(s):  
Reverse Genetics ◽  
Candida Parapsilosis ◽  
Diploid Species ◽  
Antifungal Resistance ◽  
Cross Resistance ◽  
Pathogenic Yeast ◽  
In Vitro Susceptibility ◽  
Fluconazole Resistance ◽  
The Impact

Introduction Candida parapsilosis is both a commensal/saprophytic yeast of the human skin and an opportunistic pathogen which can be responsible for life-threatening infections. The increasing reports of clonal outbreaks involving azole-resistant C. parapsilosis in the clinical setting is worrisome and urges for a better understanding of antifungal resistance in this species. Previous studies have identified mutations in key genes which can explain acquired fluconazole resistance. Reverse genetics approaches are now warranted to confirm their involvement and to determine whether they can affect other clinically-licensed antifungals. Here, we used a CRISPR-Cas9 technique to study the relative contributions of clinically-derived mutations to antifungal resistance and provide answers to these questions. Materials and Methods Six clinically-derived mutations were selected (ERG11Y132F, ERG11K143R,ERG11R398I, TAC1G650E, MRR1G583R, ERG3G111R) to be engineered in two C. parapsilosis fluconazole-susceptible backgrounds (ATCC22019, STZ5) using a previously described CRISPR-Cas9 method. In vitro susceptibility of the transformants to fluconazole, voriconazole, posaconazole, isavuconazole and micafungin was determined by Etest®. Results/Discussion The impact on fluconazole susceptibility was highly variable depending on the residue/gene involved, but roughly similar between the two genetic backgrounds. All but two(ERG11R398I, ERG3G111R) conferred fluconazole resistance, though the highest MIC increase was observed for MRR1G583R (≥650 fold). As expected in a diploid species, we noted an impact of allelic dosage. Some kind of cross-resistance to the other azoles was noted from some mutations, although the impact was lower for posaconazole and isavuconazole, except for MRR1G583R which led to multi-azole resistance. Finally, ERG3G111R increased tolerance to both azoles and echinocandins.

Calcium-Dependent Protein Kinases (CDPK) in Abiotic Stress Tolerance

2018 ◽  
Vol 34 (2) ◽  
pp. 259-265 ◽  
Author(s):  
Hemant B Kardile ◽  
◽  
Vikrant ◽  
Nirmal Kant Sharma ◽  
Ankita Sharma ◽  
...  
Keyword(s):  
Abiotic Stress ◽  
Stress Tolerance ◽  
Protein Kinases ◽  
Abiotic Stress Tolerance ◽  
Calcium Dependent ◽  
Dependent Protein ◽  
Calcium Dependent Protein Kinases
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