Organic and inorganic nitrogen effects on spore production and mycelial growth of Neonectria ditissima in vitro

2018 ◽  
Vol 71 ◽  
pp. 354
Author(s):  
Rebecca E. Campbell ◽  
Amandine Touron ◽  
Monika Walter
Keyword(s):  
Mycelial Growth ◽  
Morphological Changes ◽  
Inorganic Nitrogen ◽  
Spore Production ◽  
In Planta ◽  
Inorganic N ◽  
Causal Organism ◽  
N Sources ◽  
Plant Pathogen Interaction

Nitrogen (N) is known to influence the growth of Neonectria ditissima (N.d.), the causal organism of European canker. In vitro, inorganic N inhibits conidia germination at N concentrations above 0.2 mol/L while, in planta, foliar urea application increased disease expression of leaf scar wounds up to nine-fold. The influence of organic and inorganic N sources on mycelial growth and spore production of N.d. in vitro was investigated. Four organic and six inorganic N sources were tested on agar at concentrations of N between 0 and 0.2 mol/L, with 3 different N.d. isolates. Spore production was generally increased by the addition of low concentrations of N, with varying results at higher concentrations dependent on the N source; however, this also differed among N.d. isolates. Spore production was generally incompletely inhibited at the higher N concentrations tested. However, germination from the resulting conidia decreased, possibly due to morphological changes to the spores. Mycelial growth generally decreased with the addition of N. Understanding the N effect in planta will be further complicated by the physiological plant-N and plant-pathogen interaction processes.

scholarly journals Inhibition of Phytophthora parasitica and P. capsici by Silver Nanoparticles Synthesized Using Aqueous Extract of Artemisia absinthium

2015 ◽  
Vol 105 (9) ◽  
pp. 1183-1190 ◽  
Author(s):  
Mohammad Ali ◽  
Bosung Kim ◽  
Kevin D. Belfield ◽  
David Norman ◽  
Mary Brennan ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Aqueous Extract ◽  
Dose Response ◽  
Mycelial Growth ◽  
Plant Pathogens ◽  
Synthesis Methods ◽  
In Planta ◽  
Artemisia Absinthium ◽  
Plant Disease Management

Application of nanoparticles for controlling plant pathogens is a rapidly emerging area in plant disease management, and nanoparticles synthesis methods that are economical and ecofriendly are extensively investigated. In this project, we investigated the potential of silver nanoparticles (AgNPs) synthesized with aqueous extract of Artemisia absinthium against several Phytophthora spp., which cause many economically important crop diseases. In in vitro dose-response tests conducted in microtiter plates, 10 µg ml−1 of AgNPs inhibited mycelial growth of P. parasitica, P. infestans, P. palmivora, P. cinnamomi, P. tropicalis, P. capsici, and P. katsurae. Detailed in vitro dose-response analyses conducted with P. parasitica and P. capsici revealed that AgNPs synthesized with A. absinthium extract were highly potent (IC50: 2.1 to 8.3 µg ml−1) and efficacious (100%) in inhibiting mycelial growth, zoospore germination, germ tube elongation, and zoospore production. Interestingly, AgNP treatment accelerated encystment of zoospores. Consistent with in vitro results, in planta experiments conducted in a greenhouse revealed that AgNP treatments prevented Phytophthora infection and improved plant survival. Moreover, AgNP in in planta experiments did not produce any adverse effects on plant growth. These investigations provide a simple and economical method for controlling Phytophthora with AgNP without affecting normal plant physiology.

scholarly journals Potential of some bacteria for biological control of postharvest citrus green mould caused by Penicillium digitatum

2017 ◽  
Vol 53 (No. 3) ◽  
pp. 134-143 ◽  
Author(s):  
Mohammadi Parisa ◽  
Tozlu Elif ◽  
Kotan Recep ◽  
Kotan Merve Şenol
Keyword(s):  
Enzyme Activity ◽  
Bacillus Subtilis ◽  
Antifungal Activity ◽  
Mycelial Growth ◽  
Spore Production ◽  
Penicillium Digitatum ◽  
Broth Culture ◽  
Agrobacterium Radiobacter ◽  
Green Mould

Ten bacteria isolate (4 Bacillus subtilis, 2 Bacillus pumilus, 2 Bacillus cereus, 1 Bacillus megaterium, and 1 Agrobacterium radiobacter) were tested in vitro for antagonistic properties against Penicillium digitatum, the causal agent of citrus green mould. The effect of these bacteria was also observed on mycelial growth, spore germination, and spore production of the pathogenic fungus in broth culture. Extracellular enzyme activities of the bacteria were determined. According to the results of in vitro antagonistic tests and enzymes activities, the most promising bacteria were Bacillus subtilis and Agrobacterium radiobacter. These bacteria were tested for disease suppression on lemon fruits. In addition, these bacterial isolates also showed remarkable antifungal activity against the pathogen on lemon fruits. The results of this study showed that Bacillus subtilis and Agrobacterium radiobacter showed remarkable antifungal activity against the pathogen. Chitinase and glucanase enzyme activity of all the tested bacteria was positive. Protease enzyme activity was positive in all tested bacteria with the exception of Agrobacterium radiobacter. In addition, all bacteria inhibited mycelial growth and spore germination (except Agrobacterium radiobacter) of the fungus. Bacillus subtilis, Bacillus cereus, and Agrobacterium radiobacter inhibited spore production in broth culture. Bacillus subtilis and Agrobacterium radiobacter were tested on lemon fruits significantly reduced disease severity. Consequently, these isolates can be used as new biocontrol agents in controlling the post-harvest decay of citrus fruits caused by Penicillium digitatum.

scholarly journals Synthesis and Characterization of Novel Copper Nanoparticles for the Control of Leaf Spot and Anthracnose Diseases of Olive

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1667
Author(s):  
Panagiota Ntasiou ◽  
Alexandra Kaldeli Kerou ◽  
Theodora Karamanidou ◽  
Afrodite Vlachou ◽  
George T. Tziros ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Mycelial Growth ◽  
Crop Protection ◽  
Attenuated Total Reflection ◽  
Colletotrichum Acutatum ◽  
In Planta ◽  
Colletotrichum Spp ◽  
Type 3

Olive crop is frequently treated with copper fungicides to combat foliar and fruit diseases such as olive leaf spot caused by Fusicladium oleagineum and anthracnose caused by Colletotrichum spp. The replacement of copper-based products with more eco-friendly alternatives is a priority. Metal nanoparticles synthesized in several ways have recently revolutionized crop protection with applications against important crop pathogens. In this study, we present the development of four copper-based nanoparticles (CuNP Type 1 to 4) synthesized with a wet chemistry approach. The CuNPs were characterized using Transmission Electron Microscopy, Dynamic Light Scattering, Laser Doppler Electrophoresis, and Attenuated Total Reflection measurements. In addition, the activity of the four CuNP types was tested in vitro and in planta against F. oleagineum and Colletotrichum spp. In vitro sensitivity measurements showed that for both pathogens, mycelial growth was the most susceptible developmental stage to the tested compounds. Against both pathogens, CuNP Type 1 and Type 2 were found to be more active in reducing mycelial growth compared to the reference commercial compounds of copper oxide and copper hydroxide. In planta experiments showed that CuNP Type 3 and CuNP Type 4 exhibited a strong protectant activity against both F. oleagineum and Colletotrichum acutatum with control efficacy values significantly higher than those achieved by the applications of either reference product.

scholarly journals In vitro evaluation of grapevine endophytes, epiphytes and sap micro-organisms for potential use to control grapevine trunk disease pathogens

2021 ◽  
Author(s):  
Robert Blundell ◽  
Molly Arreguin ◽  
Akif Eskalen
Keyword(s):  
Biological Control ◽  
Mycelial Growth ◽  
Fungal Pathogens ◽  
Dual Culture ◽  
Biological Control Agents ◽  
In Planta ◽  
Eutypa Dieback ◽  
Fungal Isolates ◽  
Wound Protection

SummaryGrapevine trunk diseases (GTDs) threaten the economic sustainability of viticulture worldwide causing a significant reduction of both yields and quality of grapes. Biological control presents a promising sustainable alternative to cultural and chemical methods to mitigate the effects of pathogens causing GTDs, including Botryosphaeria dieback, Eutypa dieback and Esca. This study aimed to identify naturally occurring potential biological control agents from a variety of grapevine tissues, including sap, cane and pith and evaluate their antagonistic activity against selected fungal pathogens responsible for GTDs in vitro. Bacterial and fungal isolates were preliminary screened in vitro to determine their antifungal activity via a dual culture assay against Neofusicoccum parvum and Eutypa lata. Among the fungal isolates, Trichoderma spp. inhibited E. lata mycelial growth up to 64% and N. parvum mycelial growth up to 73% with overgrowth and stopped growth being the likely antagonistic mechanisms. Among the bacterial isolates, Bacillus spp. inhibited E. lata mycelial growth up to 20% and N. parvum mycelial growth up to 40%. Select antagonistic isolates of Trichoderma, Bacillus and Aureobasidium spp. were subject to further dual culture antifungal analysis against Diplodia seriata and Diaporthe ampelina, with Trichoderma isolates consistently causing the greatest inhibition. Volatile organic compound antifungal analysis revealed that these Trichoderma isolates resulted significantly inhibited mycelial growth of N. parvum, E. lata and D. ampelina causing up to 20.11%, 60.55% and 70.9% inhibition respectively (P≤0.05). Multilocus sequence analysis revealed that the Trichoderma isolates are most closely related to Trichoderma asperellum and Trichoderma hamatum. This study identifies grapevine sap as a novel source of potential biological control agents for control of GTDs to support existing efforts to control GTDs. Further testing will be necessary to fully characterize these microbes mode of antagonism and assess their efficacy for pruning wound protection in planta.

scholarly journals Computational proteomics analysis reveals pathogen secreted carbohydrate active enzymes in tomato xylem sap

2021 ◽  
Author(s):  
Abhijeet Roy ◽  
Barsha Kalita ◽  
Aiswarya Jayaprakash ◽  
Annamalai Arunachalam ◽  
Lakshmi PTV
Keyword(s):  
Cell Wall ◽  
Tomato Plant ◽  
Xylem Sap ◽  
In Planta ◽  
Cell Wall Degrading Enzymes ◽  
Carbohydrate Active Enzymes ◽  
Causal Organism ◽  
Degrading Enzymes ◽  
Susceptible Tomato

Abstract Fusarium oxysporum f. sp. lycopersici (Fol), a causal organism of Fusarium wilt in the tomato plant, secretes cell wall degrading enzymes, also known as carbohydrate-active enzymes (CAZymes). These are crucial during colonization and pathogenesis, as evidenced by several proteomic studies, revealing the importance of these CAZymes in virulence and pathogenicity. However, few of them have been done in-planta, exhibiting differences in the expression of these cell wall degrading enzymes compared to in-vitro studies. Therefore, to explore the CAZymes involved in pathogenesis while residing in the host plant, an in-planta (xylem sap) proteomics of a susceptible tomato variety affected with Fol was done. Most of these CAZymes belonged to the hydrolase and oxidoreductase families having no significant homology with tomato proteins. Nearly 90% of them were predicted to be soluble and extracellular. The core CAZymes families with interactional evidence identified were AA3, GH3, GH18, GH20, GH28, GH43, GH47, GH55 and CE8. Thus, apart from annotating some of the hypothetical proteins to be CAZymes, the study sheds light on CAZymes families that may have a role in the pathogenesis and survival of this fungus in the susceptible tomato plant.

scholarly journals Competitive Ability and Fitness of Alternaria alternata Isolates Resistant to QoI Fungicides

Plant Disease ◽  
2011 ◽  
Vol 95 (2) ◽  
pp. 178-182 ◽  
Author(s):  
G. S. Karaoglanidis ◽  
Y. Luo ◽  
T. J. Michailides
Keyword(s):  
Alternaria Alternata ◽  
Mycelial Growth ◽  
Competitive Ability ◽  
Spore Production ◽  
Fitness Cost ◽  
Development Of Resistance ◽  
Fitness Parameters ◽  
Resistant Strains

Fungicides that act as quinone outside inhibitors (QoIs) constitute a fungicide group extensively used against Alternaria late blight of pistachio caused by Alternaria spp. However, developement of resistance to this fungicide class constitutes an important threat for the succesful control of the disease. This study was conducted to determine whether development of resistance to QoIs is associated with a fitness cost, by measuring several biological and epidemiological parameters and estimating the competitive ability in four QoI-resistant and four QoI-sensitive Alternaria alternata isolates. Fitness parameters measured were mycelial growth and spore production in vitro, disease latent period, aggressiveness, and spore production on detached pistachio leaves. The competitive ability of resistant isolates was assessed in coinoculation experiments with sensitive isolates on detached pistachio leaves, using a real-time polymerase chain reaction assay technique. Fitness parameters between grouped QoI-resistant and QoI-sensitive isolates were not significantly different (P = 0.13, 0.21, 0.31, and 0.27 for sporulation in vitro, mycelial growth, incubation period, and sporulation in vivo, respectively), while resistant isolates, as a group, showed a higher aggressiveness (P = 0.01) compared with the sensitive isolates. The data indicate that the resistant strains did not account for a fitness cost compared with the sensitive ones under the conditions of testing. The outcome of the competition experiments was isolate dependent. In two pairs, the resistance frequencies increased whereas, in the remaining two pairs of isolates, resistance frequency decreased, suggesting that the resistant isolates were competitive similarly to the sensitive isolates.

scholarly journals Baseline Sensitivity of Pyraclostrobin and Toxicity of SHAM to Sclerotinia sclerotiorum

Plant Disease ◽  
2015 ◽  
Vol 99 (2) ◽  
pp. 267-273 ◽  
Author(s):  
Hong-Jie Liang ◽  
Ya-Li Di ◽  
Jin-Li Li ◽  
Hong You ◽  
Fu-Xing Zhu
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Mycelial Growth ◽  
Inhibitory Effect ◽  
Oxidase Inhibitor ◽  
Cross Resistance ◽  
In Planta ◽  
Baseline Sensitivity ◽  
Vitro Assay ◽  
Quinone Outside Inhibitor

Sclerotinia sclerotiorum is a cosmopolitan plant pathogen notable for its wide host range. The quinone outside inhibitor (QoI) fungicide pyraclostrobin has not been registered for control of S. sclerotiorum in China. In this study, baseline sensitivity of pyraclostrobin was established based on effective concentration for 50% inhibition of mycelial growth (EC50) values of 153 isolates of S. sclerotiorum collected from five provinces of China and toxicity of alternative oxidase inhibitor salicylhydroxamic acid (SHAM) to S. sclerotiorum was determined. Results showed that the frequency distribution of EC50 values of the 153 isolates was unimodal but with a right-hand tail. The mean EC50 value was 0.1027 μg/ml and the range of EC50 values was 0.0124 to 0.6324 μg/ml. Applied as a preventive fungicide in pot experiments, pyraclostrobin at 5, 15, and 45 μg/ml provided control efficacies of 61, 77, and 100%, respectively. There was no positive cross-resistance between pyraclostrobin and carbendazim or dimethachlon. EC50 values for SHAM against four isolates of S. sclerotiorum were 44.4, 51.8, 54.4, and 68.7 μg/ml. SHAM at 20 μg/ml could significantly increase not only the inhibitory effect of pyraclostrobin on mycelial growth on potato dextrose agar media but also the control efficacy in planta. These results indicated that SHAM should not be added into artificial media in in vitro assay of S. sclerotiorum sensitivity to pyraclostrobin. This has broad implications for assay of sensitivity of fungal pathogen to QoI fungicides.

scholarly journals Nutritional characteristics and physiological studies on the growth and development of Phlebiopsis gigantea

2017 ◽  
Vol 8 ◽  
Author(s):  
Sushma Negi ◽  
Indu Bhushan Prasher ◽  
Rajeev Kumar
Keyword(s):  
Mycelial Growth ◽  
Inorganic Nitrogen ◽  
Nitrogen Compound ◽  
Nitrogen Sources ◽  
Physical Factors ◽  
Phlebiopsis Gigantea ◽  
Nutritional Characteristics ◽  
Physiological Studies ◽  
Peptone Medium

<p>Physiological studies pertaining to the effect of physical factors, carbon and nitrogen requirement of <em>Phlebiopsis gigantea</em> were conducted to know its behaviour <em>in vitro</em>. These studies have revealed interesting results regarding its growth and reproduction behaviour. The best medium for the optimum growth is Glucose-peptone medium. The optimum temperature (28°C) and pH (5.0) is required for the optimum mycelial production of <em>Phlebiopsis gigantea</em> after 12 days of incubation. The best carbon source for the growth of the fungus is D(+)Glucose least seen in Sucrose medium. The best inorganic nitrogen sources for the growth of the fungus is Sodium nitrate. The least mycelial growth of fungus is observed in ammonium acetate and ammonium nitrate. The best organic nitrogen compound for the mycelial growth of fungus is DL-threonine.</p>

scholarly journals Plant Biostimulants: New Insights Into the Biological Control of Verticillium Wilt of Olive

2021 ◽  
Vol 12 ◽  
Author(s):  
Ana López-Moral ◽  
Carlos Agustí-Brisach ◽  
Antonio Trapero
Keyword(s):  
Biological Control ◽  
Verticillium Wilt ◽  
Mycelial Growth ◽  
Foliar Application ◽  
Control Measures ◽  
The Other ◽  
Limiting Factor ◽  
In Planta ◽  
Disease Reduction

Verticillium wilt of olive (Olea europaea subsp. europaea L.) (VWO), caused by the hemibiotrophic soil-borne fungus Verticillium dahliae Kleb., is considered the major limiting factor of this crop in Mediterranean-type climate regions of the world. The absence of effective chemical treatments makes the control of the disease difficult. In this way, the use of biostimulants and host plant defense inducers seems to be one of the most promising biological and eco-friendly alternatives to traditional control measures. Thus, the main goal of this study was to evaluate the effect of 32 products, including amino acids, micronutrients, microorganisms, substances of natural origin, copper complex-based products, and organic and inorganic salts against the disease under controlled conditions. To this end, their effects on mycelial growth and microsclerotia (MS) inhibition of V. dahliae were evaluated by means of dual cultures or by sensitivity tests in vitro as well as on disease progression in planta. Wide ranging responses to the pathogen and disease reduction levels were observed among all the products tested, suggesting multiple modes of action. Copper-based products were among the most effective for mycelial growth and MS inhibition, whereas they did not show an important effect on the reduction of disease severity in planta. Phoma sp. and Aureobasidium pullulans were the most effective in disease reduction in planta with foliar application. On the other hand, two phosphite salts, one with copper and the other with potassium, were the most effective in disease reduction in planta when they were applied by irrigation, followed by A. pullulans and Bacillus amyloliquefaciens. This study will be useful to select the best candidates for future studies, contributing significantly to new insights into the current challenge of the biological control of VWO.

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