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

Author(s):  
MB Billah ◽  
MM Sikder ◽  
MRI Mallik ◽  
MK Hossain ◽  
N Alam

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

Author(s):  
Omar Jiménez-Pérez ◽  
Gabriel Gallegos-Morales ◽  
Francisco Daniel Hernández-Castillo ◽  
Melchor Cepeda-Siller ◽  
Cesar Alejandro Espinoza-Ahumada

<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>


2019 ◽  
Vol 63 (8) ◽  
Author(s):  
Claudy Oliveira dos Santos ◽  
Eva Kolwijck ◽  
Henrich A. van der Lee ◽  
Marlou C. Tehupeiory-Kooreman ◽  
Abdullah M. S. Al-Hatmi ◽  
...  

ABSTRACT Fungal keratitis is a common but severe eye infection in tropical and subtropical areas of the world. In regions with a temperate climate, the frequency of infection is rising in patients with contact lenses and following trauma. Early and adequate therapy is important to prevent disease progression and loss of vision. The management of Fusarium keratitis is complex, and the optimal treatment is not well defined. We investigated the in vitro activity of chlorhexidine and seven antifungal agents against a well-characterized collection of Fusarium isolates recovered from patients with Fusarium keratitis. The fungus culture collection of the Center of Expertise in Mycology Radboudumc/CWZ was searched for Fusarium isolates that were cultured from cornea scrapings, ocular biopsy specimens, eye swabs, and contact lens fluid containers from patients with suspected keratitis. The Fusarium isolates that were cultured from patients with confirmed keratitis were all identified using conventional and molecular techniques. Antifungal susceptibility testing was performed according to the EUCAST broth microdilution reference method. The antifungal agents tested included amphotericin B, voriconazole, posaconazole, miconazole, natamycin, 5-fluorocytosine, and caspofungin. In addition, the activity of chlorhexidine was determined. The fungal culture collection contained 98 Fusarium isolates of confirmed fungal keratitis cases from 83 Dutch patients and 15 Tanzanian patients. The isolates were collected between 2007 and 2017. Fusarium oxysporum (n = 24, 24.5%) was the most frequently isolated species followed by Fusarium solani sensu stricto (n = 18, 18.4%) and Fusarium petroliphilum (n = 11, 11.2%). Amphotericin B showed the most favorable in vitro inhibition of Fusarium species followed by natamycin, voriconazole, and chlorhexidine, while 5-fluorocytosine, posaconazole, miconazole, and caspofungin showed no relevant inhibiting effect. However, chlorhexidine showed fungicidal activity against 90% of F. oxysporum strains and 100% of the F. solani strains. Our study supports the clinical efficacy of chlorhexidine and therefore warrants its further clinical evaluation for primary therapy of fungal keratitis, particularly in low and middle income countries where fungal keratitis is much more frequent and, currently, antifungal eye drops are often unavailable.


Author(s):  
Maria Luísa Mendes Rodrigues ◽  
Edson Hiydu Mizobutsi ◽  
Paola Junayra Lima Prates ◽  
Paula Virgínia Leite Duarte ◽  
Regina Cássia Ferreira Ribeiro ◽  
...  

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.


2013 ◽  
Vol 62 (12) ◽  
pp. 1907-1910 ◽  
Author(s):  
Sandra Patzi-Vargas ◽  
Mussaret Zaidi ◽  
Rodolfo Bernal-Reynaga ◽  
Magda León-Cen ◽  
Alba Michel ◽  
...  

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.


2021 ◽  
Vol 35 (4) ◽  
pp. 640-649
Author(s):  
Dalvan Pereira Abilio ◽  
Olívia Gomes Martins ◽  
Giovana Silva ◽  
Meire Andrade

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.


2020 ◽  
Vol 12 (1) ◽  
pp. 90-99
Author(s):  
Matthew O. ADEBOLA ◽  
Tunde S. BELLO ◽  
Esther A. SERIKI ◽  
Mariam B. AREMU

Irish potato (Solanum tuberosum) is an important worldwide food crop and one of the most popular in Nigeria. Its abundance and successful yield have been immensely affected by black scurf disease caused by Rhizoctonia solani. Harnessing a cost-effective management of this pathogenic fungus, three botanical species Acalypha wilkesiana, Moringa oleifera and Carica papaya leaves, each at concentrations of 0 mg ml-1 (control), 25 mg ml-1, 50 mg ml-1 and 75 mg ml-1 were evaluated in vitro. The plant leaf extracts were prepared using methanol and were evaluated for their toxicity using agar well diffusion method. The fungus was isolated from spoilt Irish potato with black scurf symptoms. The results showed the presence of some phytochemicals in leaf extract of each of the plants tested. The three leaves extract independently inhibited mycelial growth of R. solani. The potency of all the plant extracts increased with the increase in concentration. The highest concentration (75 mg ml-1) of M. oleifera and C. papaya evaluated, gave the highest inhibitory effect of 0.81 mm and 1.63 mm respectively, which were not significantly different (p> 0.05), but was obviously different from A. wilkesiana (2.81 mm). Furthermore, M. oleifera extract gave the highest percentage of mycelial growth inhibition of the fungus in all grades of the concentrations evaluated, whereas A. wilkesiana showed the least. The leaves of the three species are therefore recommended for in vivo control of this fungus, owing to their proven efficacy and to their cheap availability.


Author(s):  
Niroshini Gunasinghe ◽  
Martin J. Barbetti ◽  
Ming Pei You ◽  
Prabuddha Dehigaspitiya ◽  
Stephen Neate

White leaf spot pathogen: Neopseudocercosporella capsellae causes significant damage to many economically important Brassicaceae crops, including oilseed rape through foliar, stem, and pod lesions under cool and wet conditions. A lack of information on critical aspects of the pathogen’s life cycle limits the development of effective control measures. The presence of single-celled spores along with multi-celled conidia on cotyledons inoculated with multi-celled conidia suggested that the multi-celled conidia were able to form single-celled spores on the host surface. This study was designed to demonstrate N. capsellae morphological plasticity, which allows the shift between a yeast-like single-celled phase and the multi-celled hyphal phase. Separate experiments were designed to illustrate the pathogen’s morphological transformation to single-celled yeast phase from multi-celled hyphae or multi-celled macroconidia in-vitro and in-planta. Results confirmed the ability of N. capsellae to switch between two morphologies (septate hyphae and single-celled yeast phase) on a range of artificial culture media (in-vitro) or in-planta on the host surface before infection occurs. The hyphae-to-yeast transformation occurred through the production of two morphologically distinguishable blastospore (blastoconidia) types (meso-blastospores and micro-blastospores), and arthrospores (arthroconidia).


Microbiology ◽  
2009 ◽  
Vol 155 (12) ◽  
pp. 3922-3933 ◽  
Author(s):  
Jörg Bormann ◽  
Paul Tudzynski

The putative Claviceps purpurea homologue of the Saccharomyces cerevisiae stretch-activated calcium ion channel Mid1 was investigated for its role in vegetative growth, differentiation and pathogenicity on rye (Secale cereale). Gene replacement mutants of Cl. purpurea mid1 were not affected in polar growth and branching in axenic culture but showed a significantly reduced growth rate. The growth defect could not be complemented by Ca2+ supplementation, in contrast to mid1 mutants in yeast, but the altered sensitivity of the mutants to changes in external and internal Ca2+ concentrations indicates some role of Mid1 in Ca2+ homeostasis. The major effect of mid1 deletion, however, was the complete loss of virulence: infected rye plants showed no disease symptoms at all. Detailed analyses of in vitro-infected rye ovaries demonstrated that the Δmid1 mutants had multiple apical branches and were unable to infect the host tissue, suggesting that Mid1 is essential for generating the necessary mechanical force for penetration. This is believed to be the first report of an essential role for a Mid1 homologue in the virulence of a plant-pathogenic fungus.


2021 ◽  
Vol 14 ◽  
pp. 70-74
Author(s):  
Cristina-Maria Lumînare ◽  
Daniel Nicolae Cojanu ◽  
Mihaela-Monica Dinu ◽  
Ana-Cristina Fătu

"The effect of temperature on the mycelial growth of two isolates of Metarhizium anisopliae (Metch.) Sorok. (Hypocreales, Clavicipitaceae) was evaluated in vitro on PDA growth medium, by measuring the diameter of the fungal colonies, at the following temperature values: 5, 10, 15, 20, 25, 30, 35 and 40 °C, over 14 days under constant conditions. The data obtained were used for the calculation of the growth rate (mm/day) using linear regression. The representation of the values corresponding to the minimum, optimal and maximum temperature of vegetative growth was made by a curve described by a mathematical function, a modified beta (ß) function. The lowest temperatures at which growth occurs are 7 and 10°C, the highest is 35.7°C; temperature at which the most growth occurs, as indicated by the measurements, was distributed over a range of temperatures from 22.9 to 31°C."


2011 ◽  
Vol 29 (3) ◽  
pp. 342-348 ◽  
Author(s):  
Adriana Teramoto ◽  
Marise C Martins ◽  
Luciene C Ferreira ◽  
Marcos G Cunha

The fungus Corynespora cassiicola is the causal agent of target spot in cucumber. Under favorable climatic conditions it can cause serious damage in this horticultural crop. In Brazil, there exists not enough knowledge to determine efficient control measures to the disease. This investigation was carried out to evaluate: a) the reactions of nine cucumber hybrids to C. cassiicola; b) the sensibility of six isolates of C. cassiicola to fungicides in vitro (captan, chlorothalonil, mancozeb, azoxystrobin, difenoconazole, carbendazin, tebuconazole and thiophanate-methyl), used in concentrations of 0, 1, 10, 100 and 1,000 µg mL-1 of active ingredient and c) protective and curative chemical treatments with the same fungicides used in vitro in cucumber plants inoculated with C. cassiicola. The cucumber hybrids were evaluated using the scale of notes and diagrammatic of target spot severity. The more resistant hybrids to the pathogen were Taisho, Nikkey, Yoshinari and Safira. The difenoconazole fungicide caused the most mycelial growth inhibition (MGI) and showed the lowest ED50. Thiophanate-methyl was the worst fungicide, it did not inhibit the mycelial growth of the fungus. Azoxystrobin was the most efficient in controlling the disease, although it has to be registered in Ministry of Agriculture, Livestock and Food Supply in Brazil before its recommendation.


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