scholarly journals Characterization and pathogenicity of a Pythium aphanidermatum isolate causing ‘damping off’ in pepper seedlings

2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Omar Jiménez-Pérez ◽  
Gabriel Gallegos-Morales ◽  
Francisco Daniel Hernández-Castillo ◽  
Melchor Cepeda-Siller ◽  
Cesar Alejandro Espinoza-Ahumada
Keyword(s):  
Mycelial Growth ◽  
Culture Media ◽  
Agar Medium ◽  
Molecular Techniques ◽  
High Rate ◽  
Damping Off ◽  
Sexual And Asexual Reproduction ◽  
High Degree ◽  
Pepper Plants

<p>The production of the pepper seedling (<em>Capsicum annuum</em>) is affected by the fungal complex that causes the ‘damping-off’, in which some species of the oomycete <em>Pythium</em> spp., stand out. The objective of the present study was to identify the causal agent of the death of pepper plants and evaluate its pathogenicity in pepper seeds and seedlings. A fast and aggressive growing oomycete was isolate from pepper plants, morphologically identified as P. aphanidermatum based on its sexual and asexual reproduction structures and, by molecular techniques. This isolate had a high degree of<em> in vitro</em> pathogenicity in pre-emergence and post-emergence in chile, showing 100% mortality. In addition, it presented a high rate of mycelial growth in different culture media (V8-Agar, Corn Agar, Corn Potato Agar, Potato Dextrose Agar, Czapek &amp; Oat Agar), being in V8-Agar medium the only medium where it developed reproduction structures sexual and asexual. The isolation presented a mycelial growth rate of 58.3 ± 0.3 mm / day at 26 ± 2 °C in PDA medium. Due to its rapid growth and its high degree of pathogenicity <em>in vitro</em>, it is an unusual and aggressive isolate for pepper seedlings.</p>

scholarly journals Molecular characterization and vegetative growth of pathogenic seed-borne fungus, Curvularia lunata of tomato and its in vitro control measures

2022 ◽  
Vol 11 (2) ◽  
pp. 124-132
Author(s):  
MB Billah ◽  
MM Sikder ◽  
MRI Mallik ◽  
MK Hossain ◽  
N Alam
Keyword(s):  
Vegetative Growth ◽  
Mycelial Growth ◽  
Culture Media ◽  
Pathogenic Fungus ◽  
Molecular Techniques ◽  
Control Measures ◽  
Curvularia Lunata ◽  
Its Sequencing ◽  
Fungal Culture

Present studies were conducted to isolate and identify the seed-borne pathogenic fungus from the selected tomato variety through morphological and molecular techniques based on the sequencing of internal transcribed spacer (ITS) region of 18S rDNA. According to the colony and conidial features, the fungus was identified as Curvularia sp. The obtained ITS sequencing showed above 99% similarity with Curvularia lunata in the NCBI database. The sequence of the fungus was deposited in NCBI GenBank under the accession number: ITS, MH382879.1. Besides, the phylogenetic tree further confirmed the taxonomic position of the studied fungus. Growth characteristics of the fungus on nine different fungal culture media were evaluated, in which Honey peptone agar, Carrot agar, Potato sucrose agar, and Kauffman’s agar were found the most suitable. The maximum vegetative growth of the fungus was recorded at 30°C temperature and pH conditions. The bio-control potential of five different antagonists against the studied fungus was assessed, in which Trichoderma harzianum showed the better performance to restrict mycelial growth. Three ethanolic plant extracts were also evaluated, in which Lowsonia inermis L. exhibited above 60% mycelial growth inhibition of the fungus. Among three tested fungicides, Tilt 250 EC was found as an excellent fungicide to inhibit mycelial growth of C. lunata under in vitro conditions. Int. J. Agril. Res. Innov. Tech. 11(2): 124-132, Dec 2021

scholarly journals Growth and sporulation of Metarhizium flavoviride var. Flavoviride on culture media and lighting regimes

2001 ◽  
Vol 58 (3) ◽  
pp. 613-616 ◽  
Author(s):  
Sideney Becker Onofre ◽  
Cindia Mara Miniuk ◽  
Neiva Monteiro de Barros ◽  
João Lúcio Azevedo
Keyword(s):  
Biological Control ◽  
Mycelial Growth ◽  
Culture Media ◽  
Agar Medium ◽  
Potato Dextrose Agar ◽  
Continuous Illumination ◽  
Agricultural Pests ◽  
Dark Cycle ◽  
Metarhizium Flavoviride ◽  
Conidia Production

Entomopathogenic fungi from the genus Metarhizium are largely used for the biological control of agricultural pests by conidia spreading on the field. Although conidia production is well studied in M. anisopliae, only few research studies were done in M. flavoviride. The present work was carried out alming to evaluate the Mycelial growth and sporulation of the entomopathogenic fungus Metarhizium flavoviride var. flavoviride growing at 27 ± 2°C on Potato-dextrose-agar (PDA), Czapek-agar (CZP) and a complete agar medium (CM) under three lighting regimes, (continuous illumination, light/dark cycle and an black light/dark cycle) were investigated. A completely randomized 3 × 3 (culture media × lighting regime) factorial design with four replicates was used. The best mycelial growth and sporulation occurred on the PDA and CM media under continuous illumination (P <= 0,05).

scholarly journals The effect of calcium antagonists on the growth of Entamoeba histolytica in vitro

2010 ◽  
Vol 4 (1) ◽  
pp. 5-10
Author(s):  
Zahra’a Abdul-Raheem Ahmed ◽  
Ali H. Ad’hiah ◽  
Amna N. Jasim
Keyword(s):  
Entamoeba Histolytica ◽  
Calcium Antagonists ◽  
Culture Media ◽  
Agar Medium ◽  
Reproduction Rate ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Infusion Agar ◽  
Ethylene Diaminetetraacetic Acid

he E. histolytica parasite was maintained in vitro using Locke-egg medium (LEM) and Liver infusion agar medium (LIAM). The effect of two calcium antagonists (Nifedipine and Ethylene-diaminetetraacetic acid EDTA) on the growth and activity of the parasite in the two culture media was investigated. The calcium antagonists Nifedipine and EDTA inhibited the reproduction rate of E. histolytica in a concentration-dependent manner. For Nifedipine, a concentration of 41.6 mg/ml inhibited the reproduction rate to 99.7% in both media. The EDTA had an approximate effect (98.2 and 95.8)% at a concentration of 0.83 mg/ml in LEM and LIAM media, respectively. Additionally, some cases of a parasite encystment were observed in LEM medium that was treated with Nifedipine.

Variations in Pathogenicity of Three Different Forms of Rhizoctonia Inoculum and Assessment of Cultivar Resistance of Sugar Beet

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Haque ME ◽  
◽  
Parvin MS ◽  
Keyword(s):  
Seed Germination ◽  
Sugar Beet ◽  
Root Rot ◽  
Large Scale ◽  
Culture Media ◽  
Damping Off ◽  
Require Time ◽  
Time Space ◽  
The Usa

Rhizoctonia solani causes pre-emergence and post-emergence damping-off, as well as crown and root rot of sugar beet (Beta vulgaris L.), which significantly affects the yield returns in the USA and Europe. The pathogen overwinters as sclerotia or melanized mycelium. Traditionally, the resistance of cultivars to R. solani is evaluated by scoring disease reactions at the crowns and roots of older seedlings, thus resistance is not evaluated during seed germination. Moreover, earlier studies evaluated cultivars resistance to R. solani using colonized whole barley or wheat grains which, unlike sclerotia, are artificial inocula of the pathogen that require time, space and technical know-how to produce. Moreover, colonized grains are prone to contamination with other pathogens, consumed by rodents/birds while applied in the field, and are often uneconomic. Considering those limitations, a study was undertaken (1) to develop in vitro methods to generate large-scale sclerotia, (2) to compare pathogenic potentials of sclerotia, mycelia, and colonized barley grains for optimization of dampingoff assays, and (3) to evaluate Rhizoctonia resistance of selected commercial cultivars during the seed germination phase. Comparing six different culture media, we found that R. solani had the highest radial growth (8.9 ± 0.04, cm³) at 8-days and the maximum number of sclerotia produced (203 ± 4.6) at 28-days in CV8 medium. We demonstrated significant differences in pathogenicity of the three different forms of R. solani inocula and susceptibility of cultivars to preand post-emergence damping-off. The highest pre-emergence damping-off and root rot were observed with sclerotia, and the highest post-emergence dampingoff was recorded with both sclerotial and colonized barley inocula. In addition, varietal differences in susceptibility to pre- and post-emergence damping-off were noted. The highest pre-emergence damping-off was recorded on cv Crystal 101RR and lowest in Maribo MA 504. The highest post-emergence damping-off was recorded on BTS 8500 and the lowest in Crystal 467. The maximum mean root rot was observed in BTS 8500, BTS 8606, and Crystal 101R. Our studies demonstrated that sclerotia serve as efficient natural inocula, reemphasized that host-pathogen interactions differ at the early vs. late stages of sugar beet growth, and highlighted the need to reevaluate commercial sugar beet cultivars for resistance at the seed germination stage.

VARIABILITY IN SENSITIVITY TO THE FUNGICIDE PYROXYCHLOR WITHIN THE GENERA PHYTOPHTHORA AND PYTHIUM

1976 ◽  
Vol 56 (2) ◽  
pp. 365-369 ◽  
Author(s):  
LLOYD T. RICHARDSON
Keyword(s):  
Mycelial Growth ◽  
The Other ◽  
Individual Species ◽  
Systemic Fungicide ◽  
Damping Off ◽  
Response Curves ◽  
In Vitro Sensitivity ◽  
Pea Seedlings ◽  
Growth Room

A comparative study was made of the innate sensitivity of individual species within the genera Phytophthora and Pythium to the selective systemic fungicide pyroxychlor (2-chloro-6-methoxy-4-(Trichloromethyl)pyridine). In vitro sensitivity was evaluated on the basis of inhibition of mycelial growth on treated V8-juice agar. Little variation was found among the 10 Phytophtora spp. tested, the dosage response curves being linear and generally steep, with ED50 values ranging from 0.4 to 6.2 ppm. Similar steep, linear curves with low ED50 values were obtained with six Pythium spp., but five other species responded quite differently. P. sylvaticum was the most tolerant with no inhibition up to 25 ppm and only 20% at 100 ppm. The dosage response of the other species was irregular. Inhibition of P. irregulare and P. splendens reached a maximum of 50% near 1 ppm. The curve for P. ultimum also reached a maximum near 1 pp, but declined to a lower, constant level. The curve for P. polymastum was distinctly bimodal, ascending with dosage up to 0.5 ppm, descending sharply to 3.1 ppm, then ascending again. The effectiveness of pyroxychlor in controlling preemergence damping-off of pea seedlings caused by four of the Pythium spp. was compared in a growth-room test. P. aphanidermatum and P. ultimum were effectively controlled by postplant drench treatments, but P. irregulare and P. sylvaticum were not.

scholarly journals Sensitivity of Phytophthora nicotianae From Tobacco to Fluopicolide, Mandipropamid, and Oxathiapiprolin

Plant Disease ◽  
2016 ◽  
Vol 100 (10) ◽  
pp. 2119-2125 ◽  
Author(s):  
Tianli Qu ◽  
Yuanyuan Shao ◽  
Alexander S. Csinos ◽  
Pingsheng Ji
Keyword(s):  
Mycelial Growth ◽  
Agar Medium ◽  
Phytophthora Nicotianae ◽  
Limited Information ◽  
Growth Reduction ◽  
Pathogen Population ◽  
Baseline Sensitivity ◽  
Resistance Development ◽  
Black Shank

Black shank incited by Phytophthora nicotianae is a devastating disease in the production of tobacco. Fungicides have been commonly used for managing the disease; however, there is only a narrow pool of effective fungicides. A few new fungicides became available in recent years, including fluopicolide, mandipropamid, and oxathiapiprolin, which reduced diseases incited by oomycetes under field conditions. Limited information is available regarding sensitivity of P. nicotianae isolates to these new fungicides. Research was conducted to determine effects of the three new fungicides on P. nicotianae isolates from tobacco in Georgia. Studies with 106 isolates indicated that they did not grow when agar medium was amended with the fungicides at the rate of 1 μg/ml. Twenty isolates were used for in vitro studies to determine sensitivity to the fungicides. Fluopicolide, mandipropamid, and oxathiapiprolin inhibited mycelial growth of the isolates with mean EC50 values (effective concentrations that provide 50% growth reduction) of 0.09, 0.04, and 0.001 μg/ml, respectively. EC50 values of fluopicolide, mandipropamid, and oxathiapiprolin for inhibiting sporangial formation were 0.15, 0.03, and 0.0002 μg/ml, respectively. EC50 values for suppressing zoospore germination averaged 0.16, 0.04, and 0.002 μg/ml for fluopicolide, mandipropamid, and oxathiapiprolin, respectively. Results from the study indicated that P. nicotianae isolates from tobacco in Georgia were sensitive to the fungicides, with lower EC50 for oxathiapiprolin than for fluopicolide and mandipropamid. The information on effectiveness and baseline sensitivity of fungicides on P. nicotianae will facilitate monitoring of resistance development in the pathogen population.

Phosphite-based Products in the In vitro Colletotrichum musae Control

2019 ◽  
pp. 1-9
Author(s):  
Maria Luísa Mendes Rodrigues ◽  
Edson Hiydu Mizobutsi ◽  
Paola Junayra Lima Prates ◽  
Paula Virgínia Leite Duarte ◽  
Regina Cássia Ferreira Ribeiro ◽  
...  
Keyword(s):  
Mycelial Growth ◽  
Culture Medium ◽  
Culture Media ◽  
Petri Dish ◽  
State University ◽  
Randomized Design ◽  
Colletotrichum Musae ◽  
Study Laboratory ◽  
Vitro Effect

Aims: The aim of this study was to evaluate the in vitro effect of different phosphite formulations and concentrations on the development of Colletotrichum musae. Sample: to evaluate the inhibition of germination, mycelial growth and sporulation of Colletotrichum musae. Study Design:  Treatments were conducted in a completely randomized design, with 4 replicates, each replicate consisting of 1 Petri dish. Place and Duration of Study:  Laboratory of Post-Harvest Pathology, State University of Montes Claros, between March and October 2017. Methodology: Three different phosphite formulations were used: FCu1 (4% Cu + 20% P2O5), FCu2 (4% Cu + 22% P2O5) at concentrations of 0.5;1.0; 1.5 and 2.0 mL L-1 and FK (42% P2O5 + 27.7% K2O) at concentrations of 0.5; 1.0; 1.5 and 2.0 mg.L-1. Products were incorporated into the respective culture media. Culture medium alone and culture medium + imazalil were used as controls. Petri dishes were housed in BOD chamber at 25°C under a 12 hours photoperiod. Results: Results were submitted to analysis of variance and regression, and means were compared by the Tukey test (P <0.05). Control was compared to the other treatments by the Dunnet's test (P <0.05). Among the tested phosphite formulations, copper and potassium phosphites were found to reduce the mycelial growth of Colletotrichum musae. FCu2 presents a fungicide-like effect from the concentration of 0.5 m.L-1 in the control of conidia production. As for the FCu1, a fungicide-like effect was observed in the control of germination from the concentration of 1.5 mL.L-1. Conclusion: A significant fungistatic effect was observed between the concentrations of the products in the mycelial growth, sporulation and germination obtaining control of up to 100% of the development of C. musae. Copper phosphites were as effective as fungicide in inhibiting fungal development.

Persistent bloody diarrhoea without fever associated with diffusely adherent Escherichia coli in a young child

2013 ◽  
Vol 62 (12) ◽  
pp. 1907-1910 ◽  
Author(s):  
Sandra Patzi-Vargas ◽  
Mussaret Zaidi ◽  
Rodolfo Bernal-Reynaga ◽  
Magda León-Cen ◽  
Alba Michel ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Culture Media ◽  
Evidence Base ◽  
Antimicrobial Treatment ◽  
Molecular Techniques ◽  
Bloody Diarrhoea ◽  
Severe Diarrhoea ◽  
E Coli ◽  
Clinical Laboratories

Diffusely adherent Escherichia coli (DAEC) is thought to cause diarrhoea in children, and so too are other diarrhoeagenic E. coli (DEC); however, the evidence base is inconclusive. DEC pathotypes are differentiated on the basis of their pathogenic features, and thus cannot be quickly identified on selective culture media. Molecular techniques, not readily available in most clinical laboratories, are required to differentiate DEC strains from non-pathogenic E. coli in the stool flora. We report a case of persistent bloody diarrhoea, without fever, in a previously healthy 21-month infant from whom we isolated five DAEC strains. The child’s stools movements were loose, with gross blood and mucus; fresh mount analysis revealed numerous faecal leukocytes and erythrocytes. Response to antimicrobial treatment with trimethoprim-sulfamethoxazole was poor despite susceptibility in vitro. Although the patient improved with azithromycin, blood was present in the patient’s stools for over 30 days. The severe diarrhoea in this patient might be explained by the fact that these DAEC isolates harboured a siderophore receptor, which allows the bacteria to use iron derived from haem compounds that promote its multiplication. The isolates also induced in vitro secretion of several immunomodulatory cytokines that may account for the patient’s loose stools and faecal leukocytes. DAEC may play a greater role than suspected in afebrile children with bloody diarrhoea.

scholarly journals PROSPECÇÃO E AVALIAÇÃO DO POTENCIAL BIOTECNOLÓGICO DE LINHAGENS COMERCIAIS DE SHIITAKE

2021 ◽  
Vol 35 (4) ◽  
pp. 640-649
Author(s):  
Dalvan Pereira Abilio ◽  
Olívia Gomes Martins ◽  
Giovana Silva ◽  
Meire Andrade
Keyword(s):  
Wheat Bran ◽  
Radial Growth ◽  
Mycelial Growth ◽  
Culture Medium ◽  
Lentinula Edodes ◽  
Culture Media ◽  
Biotechnological Potential ◽  
E Mail ◽  
Eucalyptus Sawdust

PROSPECÇÃO E AVALIAÇÃO DO POTENCIAL BIOTECNOLÓGICO DE LINHAGENS COMERCIAIS DE SHIITAKE   DALVAN PEREIRA ABÍLIO1, OLÍVIA GOMES MARTINS2, GIOVANA CRISTINA PINTO ALVES DA SILVA3, MEIRE CRISTINA NOGUEIRA DE ANDRADE4   1 Graduando em Ciências Biológicas, Centro Universitário Sagrado Coração – Unisagrado, R. Irmã Arminda, 10-50 - Jardim Brasil, 17011-160 Bauru, SP, Brasil. E-mail: [email protected] 2 Doutoranda em Agronomia – Energia na Agricultura, Faculdade de Ciências Agronômicas, Universidade Estadual Paulista "Julio de Mesquita Filho" (UNESP), Av. Universitária, 3780 - Altos do Paraíso, 18610-034, Botucatu, SP, Brasil. E-mail: [email protected] 3 Mestre em Agronomia – Energia na Agricultura, Faculdade de Ciências Agronômicas, Universidade Estadual Paulista "Julio de Mesquita Filho" (UNESP), Av. Universitária, 3780 - Altos do Paraíso, 18610-034, Botucatu, SP, Brasil. E-mail: [email protected] 4 Docente da Faculdade Gran Tietê, Av. 15 de Novembro, 125 - Centro, 17340-000, Barra Bonita, SP, Brasil. E-mail: [email protected]   RESUMO: O objetivo deste trabalho foi avaliar e comparar o crescimento micelial in vitro de quatro linhagens comerciais de Lentinula edodes (LE-241, LE-242, LE-243 e LE-244) em meio de cultura à base de serragem de eucalipto, suplementado com bagaço de malte ou farelo de trigo. O delineamento experimental foi inteiramente casualizado, em esquema fatorial 2x4 (substratos x linhgens), totalizando oito tratamentos, cada um com cinco repetições. Os substratos foram preparados com 20% de suplementação, acrescidos de calcário (tamponante), umidificados e esterilizados. Os meios de cultura foram preparados a partir da infusão dos substratos, filtração, adição de ágar e esterilização. As placas foram inoculadas com as linhagens e o crescimento radial do micélio na superfície do meio de cultura foi mensurado com paquímetro. O menor desenvolvimento micelial ocorreu com a linhagem LE-241 e com a linhagem LE-243 no substrato suplementado com farelo de trigo. Os maiores desenvolvimentos foram obtidos com as linhagens LE-242 e LE-244 no substrado suplementado com bagaço de malte. O desenvolvimento de todas as linhagens foi maior no substrato suplementado com bagaço de malte. Sendo assim, a utilização do bagaço de malte para o crescimento micelial é uma alternativa viável à suplementação tradicional com farelo de trigo.   Palavras-chave: fungos, cogumelo, Lentinula edodes, micélio, bagaço de malte.   PROSPECTING AND EVALUATING THE BIOTECHNOLOGICAL POTENTIAL OF SHIITAKE COMMERCIAL STRAINS   ABSTRACT: This study aimed to evaluate and compare the in vitro mycelial growth of four commercial Lentinula edodes strains (LE-241, LE-242, LE-243 and LE-244) in a culture medium based on eucalyptus sawdust, supplemented with malt bagasse or wheat bran. The experimental design was completely randomized, in a 2x4 factorial scheme (substrates x strains), totaling eight treatments, each with five repetitions. The substrates were prepared with 20% supplementation, added with lime (buffer), humidified and sterilized. The culture media were prepared from the infusion of substrates, filtration, addition of agar and sterilization. The plates were inoculated with the strains and the radial growth of the mycelium on the surface of the culture medium was measured using a caliper. The smallest mycelial growth occurred with the LE-241 strain and with the LE-243 strain on the substrate supplemented with wheat bran. The greatest growths were obtained with the LE-242 and LE-244 strains in the substrate supplemented with malt bagasse. The development of all strains was greater in the substrate supplemented with malt bagasse. Therefore, the use of malt bagasse for mycelial growth is a viable alternative to traditional wheat bran supplementation.   Keywords: fungi, mushroom, Lentinula edodes, mycelium, malt bagasse.

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