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Aislamiento y selección de cepas de Trichoderma antagonistas a Sclerotinia sclerotiorum y Sclerotinia minor Isolation and screening of Trichoderma strains antagonistic to Sclerotinia sclerotiorum and Sclerotinia minor
Verónica Azucena Ibarra-Medina,Ronald Ferrera-Cerrato,Alejandro Alarcón,María Encarnación Lara-Hernández
Revista mexicana de micología , 2010,
Abstract: Sclerotinia sclerotiorum (Ss) y Sclerotinia minor (Sm) afectan severamente más de 400 especies de plantas, y pueden causar reducciones en rendimiento por arriba del 50%. Con el propósito de obtener microorganismos potenciales para el control de ambos patógenos, se realizó el aislamiento de cepas de Trichoderma a partir de muestras de suelo con diferente uso agrícola y forestal. Setenta y un aislados fúngicos de Trichoderma (IBA) fueron obtenidos a través de técnica de trampas con esclerocios. Subsecuentemente, se evaluó su capacidad micoparasítica sobre micelio y esclerocios de ambos fitopatógenos mediante cultivos duales in vitro. Los más altos porcentajes de colonización (>90%) de las cepas de Trichoderma sobre Ss y Sm fueron observados para los aislamientos IBA-3, IBA-4, IBA-38, e IBA-54. En general, la habilidad de los aislamientos de Trichoderma para parasitar y degradar esclerocios fue agresiva en los aislamientos IBA-3, IBA-4, IBA-23, IBA-38, IBA-46, IBA-54, e IBA-56. Con base en criterios morfológicos, cuatro de los más prominentes aislamientos fueron identificados como T. viride (IBA-4), T. pseudokoningii (IBA-23), T harzianum (IBA-38), y T. virens (IBA-46). Estas cepas de Trichoderma tienen importante potencial como antagonistas de Ss and Sm. Sclerotinia sclerotiorum (Ss) and Sclerotinia minor (Sm) drastically affect more than 400 plant species, and may cause crop yield reductions up to 50%. With the purpose to obtain potential microorganisms to control both pathogens, the isolation of Trichoderma strains from soil samples with different agricultural and forestry use was performed. Seventy-one fungal Trichoderma isolates (IBA) were obtained through sclerotia-trap techniques. Subsequently their mycoparasitic activities on mycelium as well as on sclerotia of both phytopathogens were assessed by in vitro dual cultures. The highest percentages of colonization (>90%) of the Trichoderma strains on Ss and Sm were found for the isolates IBA-3, IBA-4, IBA-38, IBA-54. The ability of Trichoderma strains to parasitize and to degrade sclerotia in general was aggressive for the strains IBA-3, IBA-4, IBA-23, IBA-38, IBA-46, IBA-54, and IBA-56. Based on morphological criteria, four of the most prominent strains were identified as T. viride (IBA-4), T. pseudokoningii (IBA-23), T. harzianum (IBA-38), and T. virens (IBA-46). These Trichoderma strains have important potential as antagonists to Ss and Sm.
Viabilidade de escleródios de Sclerotinia sclerotiorum e incidência de fungos antagonistas em solo de Cerrado
Ferraz, Leila de Castro Louback;Nasser, Luiz Carlos Bhering;Café-Filho, Adalberto Corrêa;
Summa Phytopathologica , 2011, DOI: 10.1590/S0100-54052011000400009
Abstract: the viability of sclerotia of sclerotinia sclerotiorum was assessed for eight months in three cultivated cerrado soils. sclerotia produced in vitro were placed in nylon mesh bags and buried 5 cm deep in soils either previously treated or untreated with methyl bromide. after 10 days of incubation, sclerotia were retrieved and were examined for viability and presence of antagonistic fungi. viability was assessed based on the number of sclerotia germinated after a 7-day incubation period on semi-selective neon-s medium. viability of the sclerotia varied among cerrado soils. sclerotia from soils not treated with methyl bromide were less viable and were often contaminated by antagonistic fungi, indicating the presence of suppressive elements of biological origin in the untreated cerrado soils. sclerotium viability was negatively related to the population of some soil microorganisms. treatments with higher incidences of trichoderma spp. also presented lower sclerotium viability, and fumigation strongly suppressed this antagonist.
Antagonism of Aspergillus terreus to Sclerotinia sclerotiorum
Melo, Itamar S.;Faull, Jane L.;Nascimento, Rosely S.;
Brazilian Journal of Microbiology , 2006, DOI: 10.1590/S1517-83822006000400002
Abstract: an aspergillus terreus strain showed in vitro antagonistic activity against the plant pathogen sclerotinia sclerotiorum (lib.) de bary. the interaction between a. terreus and sclerotia revealed that the mycoparasite sporulated abundantly on the sclerotial surface. cell breakdown due to host cell wall disruption was observed in inner rind cells, by a scanning electron microscopy.
Interaction of phenolic compounds with pectinases from Sclerotinia sclerotiorum  [cached]
SUCHETA SHARMA, HARMANDEEP and GIRIDHAR SONI
Indian Phytopathology , 2012,
Abstract: Activities of both pectinases (polygalacturonase and pectin methyl esterase) from Sclerotinia sclerotiorum increased with the growth period of fungus upto 7 days of growth and declined as the growth period was further progressed.
Engineering Sclerotinia Sclerotiorum Resistance in Oilseed Crops
Guihua Lu
African Journal of Biotechnology , 2003,
Abstract: The fungal pathogen Sclerotinia sclerotiorum (Lib.) de Bary is worldwide in distribution and pathogenic to more than 400 plant species. This disease causes significant yield losses of various important crops including sunflower, canola, and soybean. Applying fungicides and crop rotation are currently the major methods of controlling this disease. However, fungicide chemicals are expensive, not all environmentally safe, and not always effective. Few genetic sources of resistance to the pathogen are available to breeders. Therefore, farmers have a continuing demand for new approaches to control the disease. Biotechnology opens a new avenue to control this pathogen. Several strategies, including detoxification, defense activation, and fungal inhibition, have potential to engineer Sclerotinia resistance. This review summarizes the progress of transgenic Sclerotinia resistance in oilseed crops including sunflower, canola, and soybean.
Isolation and screening of Trichoderma strains antagonistic to Sclerotinia sclerotiorum and Sclerotinia minor
Ibarra-Medina, Verónica Azucena;Ferrera-Cerrato, Ronald;Alarcón, Alejandro;Lara-Hernández, María Encarnación;Valdez-Carrasco, Jorge Manuel;
Revista mexicana de micología , 2010,
Abstract: sclerotinia sclerotiorum (ss) and sclerotinia minor (sm) drastically affect more than 400 plant species, and may cause crop yield reductions up to 50%. with the purpose to obtain potential microorganisms to control both pathogens, the isolation of trichoderma strains from soil samples with different agricultural and forestry use was performed. seventy-one fungal trichoderma isolates (iba) were obtained through sclerotia-trap techniques. subsequently their mycoparasitic activities on mycelium as well as on sclerotia of both phytopathogens were assessed by in vitro dual cultures. the highest percentages of colonization (>90%) of the trichoderma strains on ss and sm were found for the isolates iba-3, iba-4, iba-38, iba-54. the ability of trichoderma strains to parasitize and to degrade sclerotia in general was aggressive for the strains iba-3, iba-4, iba-23, iba-38, iba-46, iba-54, and iba-56. based on morphological criteria, four of the most prominent strains were identified as t. viride (iba-4), t. pseudokoningii (iba-23), t. harzianum (iba-38), and t. virens (iba-46). these trichoderma strains have important potential as antagonists to ss and sm.
Alternative products in the "in vitro" inhibition of Sclerotinia sclerotiorum
Mello, Alexandre Furtado Silveira;Louren?o, Silvia de Afonseca;Amorim, Lilian;
Scientia Agricola , 2005, DOI: 10.1590/S0103-90162005000200014
Abstract: the white mold, caused by sclerotinia sclerotiorum, is a very important disease in tomato crops. the objective of this work was to study the effect of plant extracts, animal residues and industrial by-products extracts on the fungus in vitro growth. treatments consisted of different concentrations of pyrolignous oil, neem oil, monosodium glutamate, sewage sludge and organic compost [coffee residue (50%) coal residue (10%), maize residue (25%), poultry waste (12.5%), poultry meal (2.5%)]. positive control consisted of petri dishes with pda medium and negative control treatment consisted of pda medium with procymidone. fungus colonies were incubated at 22oc and light intensity of 260 lux. variables such as mycelium growth rate, sclerotia production, and viability 7 and 17 days after the transfer of mycelium disc to neon media were assessed. the extract of organic compost at 30% was effective in controlling mycelial growth and sclerotia production. this treatment, as well as neem oil at 0.5% increased soil respiration.
Alternative products in the "in vitro" inhibition of Sclerotinia sclerotiorum  [cached]
Mello Alexandre Furtado Silveira,Louren?o Silvia de Afonseca,Amorim Lilian
Scientia Agricola , 2005,
Abstract: The white mold, caused by Sclerotinia sclerotiorum, is a very important disease in tomato crops. The objective of this work was to study the effect of plant extracts, animal residues and industrial by-products extracts on the fungus in vitro growth. Treatments consisted of different concentrations of pyrolignous oil, neem oil, monosodium glutamate, sewage sludge and organic compost [coffee residue (50%) coal residue (10%), maize residue (25%), poultry waste (12.5%), poultry meal (2.5%)]. Positive control consisted of Petri dishes with PDA medium and negative control treatment consisted of PDA medium with procymidone. Fungus colonies were incubated at 22oC and light intensity of 260 lux. Variables such as mycelium growth rate, sclerotia production, and viability 7 and 17 days after the transfer of mycelium disc to neon media were assessed. The extract of organic compost at 30% was effective in controlling mycelial growth and sclerotia production. This treatment, as well as neem oil at 0.5% increased soil respiration.
Variability in cauliflower stalk rot pathogen Sclerotinia sclerotiorum  [cached]
S. BANIK* and PRATIBHA SHARMA
Indian Phytopathology , 2011,
Abstract: Genetic and pathogenic variability of Sclerotinia sclerotiorum causing stalk rot of cauliflower were studied. Ten isolates collected two from each of the five states namely Chhattisgarh (Ch1, Ch2), Delhi (D1, D2), Himachal Pradesh (HP1, HP2), Uttaranchal (U1, U2) and West Bengal (WB1, WB2) were used to study genetic variability of S. sclerotiorum infecting cauliflower in terms of Mycelial Compatibility Groups (MCGs). Four arbitrary MCGs were formed based on compatible and incompatible reaction. MCG 3 comprised of four isolates and the other MCGs (MCG 1, 2 AND 4) comprised of two isolates each. Isolates belonging to one MCG were compatible among each other but incompatible to isolates belonging to other MCGs. In terms of pathogenicity a narrow range of disease index values were obtained from the ten isolates. Highest disease index value of 36.1 was recorded with U1 isolate followed by D1 isolate when tested on cauliflower variety Pusa Synthetic in an artificial epiphytotic condition. The lowest disease index value of 28.9 was recorded with WB1 isolate. Based on pathogenicity reaction three groups were formed out of ten isolates. Isolates belonging to ten MCG differed significantly in terms of pathogenicity.
New apiaceous hosts of Sclerotinia sclerotiorum in the Cerrado region of Brazil
Reis, A;Nascimento, WM;
Horticultura Brasileira , 2011, DOI: 10.1590/S0102-05362011000100021
Abstract: this paper reports for the first time in the cerrado region of brazil the occurrence of white mold caused by sclerotinia sclerotiorum in coriander (coriandum sativum), parsley (petroselinum crispum) and peruvian carrot (arracacia xanthorrhiza). the disease was observed on coriander, in cristalina, goiás state, on parsley in gama, the federal district and on peruvian carrot in ibiá, minas gerais state. pathogenicity tests demonstrated that the fungus s. sclerotiorum is the causal agent of the observed symptoms in these plants. the three isolates obtained from naturally infected plants were inoculated in coriander (cv. verd?o), parsley (cv. lisa gigante), peruvian carrot (cv. amarela de senador amaral) and carrot (cv. forto nantes) and they were pathogenic to these hosts. the fungus isolates were re-isolated from inoculated plants fulfilling koch′s postulates and also confirming that s. sclerotiorum is a polyphagous pathogen.
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