scholarly journals Assessing the effectiveness of oxathiapiprolin towards Phytophthora agathidicida, the causal agent of kauri dieback disease

FEMS Microbes ◽  
2021 ◽  
Author(s):  
Randy F Lacey ◽  
Michael J Fairhurst ◽  
Kaitlyn J Daley ◽  
Te Amohaere Ngata-Aerengamate ◽  
Haileigh R Patterson ◽  
...  
Keyword(s):  
Life Cycle ◽  
New Zealand ◽  
Mycelial Growth ◽  
Phytophthora Species ◽  
Effective Concentration ◽  
Dependent Manner ◽  
Life Cycle Stages ◽  
Leaf Infection ◽  
Dieback Disease ◽  
Dose Dependent

Abstract Phytophthora species cause disease and devastation of plants in ecological and horticultural settings worldwide. A recently identified species, P. agathidicida, infects and ultimately kills the treasured kauri trees (Agathis australis) that are endemic to New Zealand. Currently there are few options for managing kauri dieback disease. In this study, we sought to assess the toxicity of the oomycide oxathiapiprolin against several life cycle stages of two geographically distinct P. agathidicida isolates. The effective concentration to inhibit 50% of mycelial growth (EC50) was determined to be approximately 0.1 ng/ml, indicating that P. agathidicida mycelia are more sensitive to oxathiapiprolin than those from most other Phytophthora species that have been studied. Oxathiapiprolin was also highly effective at inhibiting the germination of zoospores (EC50 = 2–9 ng/ml for the two isolates) and oospores (complete inhibition at 100 ng/ml). In addition, oxathiapiprolin delayed the onset of detached kauri leaf infection in a dose-dependent manner. Collectively, the results presented here highlight the significant potential of oxathiapiprolin as a tool to aid in the control of kauri dieback disease.

scholarly journals Assessing the effectiveness of oxathiapiprolin towards Phytophthora agathidicida, the causal agent of kauri dieback disease

2021 ◽  
Author(s):  
Randy F. Lacey ◽  
Michael J. Fairhurst ◽  
Kaitlyn J. Daley ◽  
Te Amohaere Ngata-Aerengamate ◽  
Haileigh R. Patterson ◽  
...  
Keyword(s):  
New Zealand ◽  
Mycelial Growth ◽  
Effective Concentration ◽  
Complete Inhibition ◽  
Dependent Manner ◽  
Significant Potential ◽  
Leaf Infection ◽  
Half Maximal Effective Concentration ◽  
Dieback Disease ◽  
Dose Dependent

AbstractPhytophthora species cause disease and devastation of plants in ecological and horticultural settings worldwide. A recently identified species, P. agathidicida, infects and ultimately kills the treasured kauri trees that are endemic to New Zealand. Currently there are few options for controlling or treating P. agathidicida. In this study, we sought to assess the toxicity of the oomycide oxathiapiprolin against several lifecycle stages of two geographically distinct P. agathidicida isolates. Half maximal effective concentration (EC50) values were determined to be approximately 0.1 ng/ml for inhibiting mycelial growth, indicating that P. agathidicida mycelia are more sensitive to oxathiapiprolin than those from most other Phytophthora species that have been studied. Oxathiapiprolin was also highly effective at inhibiting the germination of zoospores (EC50 = 2-9 ng/ml for the two isolates) and oospores (complete inhibition at 100 ng/ml). In addition, oxathiapiprolin delayed the onset of detached kauri leaf infection in a dose-dependent manner. Collectively, the results presented here highlight the significant potential of oxathiapiprolin as a tool to aid in the control of kauri dieback disease.

scholarly journals Inhibition of SARS-CoV-2 Infection by the Cyclophilin Inhibitor Alisporivir (Debio 025)

2020 ◽  
Vol 64 (7) ◽  
Author(s):  
Laurent Softic ◽  
Rozenn Brillet ◽  
François Berry ◽  
Nazim Ahnou ◽  
Quentin Nevers ◽  
...  
Keyword(s):  
Life Cycle ◽  
Effective Concentration ◽  
Dependent Manner ◽  
Phase 2 ◽  
Proof Of Concept ◽  
Phase 2 Trial ◽  
Dose Dependent ◽  
Cyclophilin Inhibitor

ABSTRACT Cyclophilins play a key role in the life cycle of coronaviruses. Alisporivir (Debio 025) is a nonimmunosuppressive analogue of cyclosporine with potent cyclophilin inhibition properties. Alisporivir reduced SARS-CoV-2 RNA production in a dose-dependent manner in Vero E6 cells, with a 50% effective concentration (EC50) of 0.46 ± 0.04 μM. Alisporivir inhibited a postentry step of the SARS-CoV-2 life cycle. These results justify rapidly conducting a proof-of-concept phase 2 trial with alisporivir in patients with SARS-CoV-2 infection.

scholarly journals Effect of Ethanol Vapor Treatment on the Growth of Alternaria alternata and Botrytis cinerea and Defense-Related Enzymes of Fungi-Inoculated Blueberry During Storage

2021 ◽  
Vol 12 ◽  
Author(s):  
Yaru Ji ◽  
Wenzhong Hu ◽  
Jia Liao ◽  
Zhilong Xiu ◽  
Aili Jiang ◽  
...  
Keyword(s):  
Botrytis Cinerea ◽  
Alternaria Alternata ◽  
Mycelial Growth ◽  
Ethanol Vapor ◽  
Defense Responses ◽  
Dependent Manner ◽  
Practical Application ◽  
Structure And Ultrastructure ◽  
Dose Dependent ◽  
Vapor Treatment

The aim of the present study was to investigate the effects of ethanol vapor on the inhibition of Alternaria alternata and Botrytis cinerea in postharvest blueberry and the induction of defense-related enzymes (DREs) activities in fungi-inoculated blueberries stored at 0±0.5°C for 16days. Results indicated that ethanol vapor markedly inhibited the mycelial growth of A. alternata and B. cinerea in a dose-dependent manner, with inhibition rates of 9.1% (250μlL−1), 36.4% (500μlL−1), and 5.5% (1,000μlL−1) on A. alternata and 14.2% (250μlL−1), 44.7% (500μlL−1), and 76.6% (1,000μlL−1) on B. cinerea, respectively. Meanwhile, ethanol vapor also enhanced the activities of DREs in fungi-inoculated blueberries, including β-1,3-glucanase (GLU), chitinase (CHI), phenylalnine ammonialyase (PAL), peroxidase (POD), and polyphenol oxidase (PPO). In particular, 500μlL−1 ethanol vapor increased the activities of DREs by 84.7% (GLU), 88.0% (CHI), 37.9% (PAL), 85.5% (POD), and 247.0% (PPO) in A. alternata-inoculated blueberries and 103.8% (GLU), 271.1% (CHI), 41.1% (PAL), 148.3% (POD), and 74.4% (PPO) in B. cinerea-inoculated blueberries, respectively. But, the activity of PPO was decreased by 55.2 and 31.9% in 500μlL−1 ethanol-treated blueberries inoculated with A. alternata and B. cinerea, respectively, after 8days of storage. Moreover, the surface structure and ultrastructure of 500μlL−1 ethanol-treated blueberry fruit cells were more integrated than those of other treatments. The findings of the present study suggest that ethanol could be used as an activator of defense responses in blueberry against Alternaria and Botrytis rots, by activating DREs, having practical application value in the preservation of postharvest fruit and vegetables.

scholarly journals Impact of Azoxystrobin, Dimethomorph, Fluazinam, Fosetyl-Al, and Metalaxyl on Growth, Sporulation, and Zoospore Cyst Germination of Three Phytophthora spp.

Plant Disease ◽  
2000 ◽  
Vol 84 (4) ◽  
pp. 454-458 ◽  
Author(s):  
M. E. Matheron ◽  
M. Porchas
Keyword(s):  
Life Cycle ◽  
Disease Control ◽  
Mycelial Growth ◽  
Phytophthora Capsici ◽  
Effective Concentration ◽  
The Other ◽  
In Vitro Activity ◽  
Phytophthora Spp ◽  
Cyst Germination

In vitro activity of azoxystrobin, dimethomorph, and fluazinam on growth, sporulation, and zoospore cyst germination of Phytophthora capsici, P. citrophthora, and P. parasitica was compared to that of fosetyl-Al and metalaxyl. The 50% effective concentration (EC50) values for)inhibition of mycelial growth of the three pathogens usually were lowest for dimethomorph and (metalaxyl, ranging from <0.1 to 0.38 μg/ml. However, the 90% effective concentration (EC90) levels for dimethomorph always were lower than the other four tested compounds, with values ranging from 0.32 to 1.6 μg/ml. Mycelial growth of P. capsici, P. citrophthora, and P. parasitica was least affected by azoxystrobin and fluazinam, with estimated (EC90) values >3,000 μg/ml. Reduction of sporangium formation by P. capsici, P. citrophthora, and P. parasitica in the presence of dimethomorph at 1 μg/ml was significantly greater than that recorded for the same concentration of azoxystrobin, fluazinam, and fosetyl-Al. For the three species of Phytophthora, zoospore motility was most sensitive to fluazinam (EC50 and EC90 values of <0.001 μg/ml) and (least sensitive to fosetyl-Al, with (EC50 and EC90 values ranging from 299 to 334 and 518 to 680 μg/ml, respectively). Germination of encysted zoospores of P. capsici, P. citrophthora, and P. parasitica was most sensitive to dimethomorph (EC50 and EC90 values ranging from 3.3 to 7.2 and 5.6 to 21 μg/ml, respectively), intermediate in sensitivity to fluazinam (EC50 and EC90 from 18 to 108 and 67 to >1,000 μg/ml, respectively) and metalaxyl (EC50 and EC90 from 32 to 280 and 49 to 529 μg/ml, respectively), and lowest in sensitivity to azoxystrobin and fosetyl-Al (EC50 and EC90 from 256 to >1,000 μg/ml). The activity of azoxystrobin, dimethomorph, and fluazinam on one or more stages of the life cycle of P. capsici, P. citrophthora, and P. parasitica suggests that these compounds potentially could provide Phytophthora spp. disease control comparable to that of the established fungicides fosetyl-Al and metalaxyl.

scholarly journals Reduced sensitivity to carbendazim in isolates of Botrytis allii

2007 ◽  
Vol 60 ◽  
pp. 108-113 ◽  
Author(s):  
S.L.H. Viljanen-Rolinson ◽  
M.V. Maroni ◽  
R.C. Butler
Keyword(s):  
New Zealand ◽  
Mycelial Growth ◽  
Management Strategy ◽  
Resistance Management ◽  
Maximum Growth ◽  
Effective Concentration ◽  
Variable Response ◽  
Growth Study ◽  
Onion Seed ◽  
Botrytis Allii

Fifty isolates of Botrytis allii causing onion botrytis neck rot were obtained from onion seed and bulbs throughout New Zealand and tested for their sensitivity to carbendazim (benzimidazole) fungicide in a mycelial growth study Agar plates amended with carbendazim at 6 or 8 different concentrations were inoculated with an 8 mm disc of mycelium of each of the isolates and incubated in the dark at 20C Radial growth of the colonies was measured after 4 days EC50 (effective concentration required to give half of maximum growth) values were estimated by fitting logistic curves with growth as a proportion of the maximum growth Of the 50 isolates 16 were identified as resistant 32 as sensitive and two had a variable response The estimated EC50 values for the isolates that were sensitive ranged from 0006 to 0053 g/ml active ingredient It is recommended that New Zealand onion growers closely follow the current benzimidazole resistance management strategy

scholarly journals Hormetic Effects of Flusilazole Preconditioning on Mycelial Growth and Virulence of Sclerotinia sclerotiorum

Plant Disease ◽  
2018 ◽  
Vol 102 (6) ◽  
pp. 1165-1170 ◽  
Author(s):  
Xiaoming Lu ◽  
Shun He ◽  
Hongju Ma ◽  
Jianhong Li ◽  
Fuxing Zhu
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Mycelial Growth ◽  
Dose Range ◽  
Pathogenic Fungi ◽  
Phytopathogenic Fungi ◽  
Dependent Manner ◽  
Inhibitory Effects ◽  
Mycelia Growth ◽  
Dmi Fungicides ◽  
Dose Dependent

Hormetic effects of fungicides are highly relevant to fungicide applications and management of plant-pathogenic fungi. Preconditioning (i.e., early exposure to relatively low doses of a toxicant) is a special form of hormesis, and fungicide preconditioning of phytopathogenic fungi is inevitable in the field. The present study showed that spraying the demethylation inhibitor (DMI) fungicide flusilazole at 0.1 µg/ml had stimulatory effects on the virulence of Sclerotinia sclerotiorum inoculated at 1 and 24 h after spraying. Flusilazole sprayed at 10 µg/ml showed inhibitory effects on the virulence of S. sclerotiorum inoculated during the first 3 days after spraying. Inoculations on the 5th, 7th, and 10th day after spraying did not show any significant inhibitory or stimulatory effects on the virulence. After growing for 2 days on potato dextrose agar (PDA) amended with flusilazole at a dose range from 0.0005 to 0.25 µg/ml as preconditioning treatments, mycelia were transferred onto PDA without fungicide and subsequent mycelial growth was slower than the nonpreconditioned control. However, after the preconditioned colonies were transferred onto PDA supplemented with flusilazole at 0.2 µg/ml, percent stimulations of mycelia growth compared with the control had a parabolic shape across the preconditioning flusilazole concentration range. Similarly, the mycelial growth of the preconditioned mycelial plugs on PDA amended with other DMI fungicides (prochloraz or tebuconazole) also showed a typical hormetic response, whereas mycelial growth on PDA amended with carbendazim or dimethachlone was inhibited in a dose-dependent manner. Preconditioning S. sclerotiorum with flusilazole on rapeseed plants elicited virulence stimulations in a dose-dependent manner similar to those on mycelial growth on PDA. After disease lesions developed on rapeseed leaves sprayed with flusilazole as the preconditioning treatment were inoculated onto rapeseed plants, virulence was inhibited on leaves without fungicide or sprayed with carbendazim or dimethachlone compared with the nonpreconditioned control, whereas virulence was stimulated on leaves sprayed with flusilazole, prochloraz, or tebuconazole, and the maximum percent stimulation was 10.2%. These results will advance our understanding of hormetic effects of fungicides and of preconditioning hormesis in particular.

scholarly journals In vitro inhibitory effect of herbal organic formulations on mycelial growth of Pea wilt pathogen Fusarium oxysporum

2020 ◽  
Vol 5 (01) ◽  
pp. 110-112
Author(s):  
W. Tampakleima Chanu ◽  
Bireswar Sinha ◽  
Kota Chakrapani
Keyword(s):  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Mycelial Growth ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
In Vitro Growth ◽  
Inhibitory Activities ◽  
Organic Formulations ◽  
Dose Dependent

The objective of this study was to determine inhibitory activities of three herbal organic formulations (fungidote, viridote, and bacteridote) on in vitro growth of Fusarium oxysporum causing Fusarium wilt of a pea in Manipur. In vitro results showed that these formulations inhibited the mycelial growth of F. oxysporum in a dose-dependent manner. Fungidote was found to be the most in reducing mycelial growth compared to the other two formulations at different concentrations. These results underpin that formulations could be used in eco-friendly disease management of Fusarium wilt of a pea.

scholarly journals The Influence of Polystyrene Microspheres Abundance on Development and Feeding Behavior of Artemia salina (Linnaeus, 1758)

2021 ◽  
Vol 11 (8) ◽  
pp. 3352
Author(s):  
Marco Albano ◽  
Giuseppe Panarello ◽  
Davide Di Paola ◽  
Fabiano Capparucci ◽  
Rosalia Crupi ◽  
...  
Keyword(s):  
Life Cycle ◽  
Feeding Behavior ◽  
Dunaliella Salina ◽  
Food Source ◽  
Developmental Stages ◽  
Artemia Salina ◽  
Dependent Manner ◽  
Polystyrene Microspheres ◽  
The Impact ◽  
Dose Dependent

In the present study, it has been evaluated how 10 µm of polyethylene microspheres can be ingested by Artemia salina (Linnaeus, 1758) larvae within the first 7 days of the life cycle, and the impact on their health. Twelve A. salina larvae (instar I) groups were exposed to different microplastics (MPs) concentrations (0-1-10-102-103-104 MPs/mL), with and without Dunaliella salina as a food source. The results highlighted that A. salina larvae ingest MPs in relation to the exposure times in a dose-dependent manner and are significantly influenced by food availability. The highest contamination found was 306.2 MPs/individual at 104 MPs/mL exposure without a food source. No MPs were found in the presence of the food source from 1 to 102 MPs/mL, while contamination was detected at all concentrations of MPs without a food source. The worst effect on the developmental stages was evaluated at 168 h with a food source, with a delay compared to the control of I and II instars at 103 and 104 MPs/mL, respectively. Furthermore, microalgal feeding was significantly reduced for about 50% in the presence of 104 MPs/mL. These results highlight that aquatic microplastics pollution could affect the A. salina’s feeding behavior and life cycle.

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