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Controle físico e biológico de Fusarium oxysporum f. sp. zingiberi em gengibre; Physical and biological control of Fusarium oxysporum f. sp. zingiberi in ginger

Domingues, Fernanda
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 19/04/2006 PT
Relevância na Pesquisa
27.3%
O Amarelo ou Murcha de Fusarium, causado por Fusarium oxysporum f. sp. zingiberi vem assumindo grande importância na cultura do gengibre devido à ausência de métodos eficientes de controle. Com os objetivos de testar a termoterapia associada ao tratamento químico e biológico para a obtenção de rizomas-semente sadios e avaliar a indução de supressividade do solo a Fusarium oxysporum f. sp. zingiberi com a incorporação de casca de camarão, seis ensaios foram conduzidos. Para o tratamento térmico, foram utilizados rizomas infectados, com aproximadamente 5cm de comprimento. As relações tempo-temperatura utilizadas foram: 45°C por zero, 60, 120 e 180 minutos e 50°C por zero, dez e 20 minutos (ensaio 1 e campo); 50°C por zero, 30 e 60 minutos e 55°C por zero, 10 e 20 minutos (ensaio 2); 50, 55 e 60ºC por zero, 10 e 20 min (ensaio 3). As caldas para tratamento térmico foram constituídas por água, solução de tiofanato metílico e caldo fermentado por Bacillus subtilis. No experimento em laboratório, os rizomas foram inoculados artificialmente. Após uma semana, receberam o tratamento térmico a 45º C por 60, 120 e 180 minutos e a 50ºC e 55ºC por 10e 20 minutos. Após a termoterapia, segmentos de rizoma foram plaqueados...

Efeito de hidrolisado de peixe sobre o crescimento micelial e controle de Cylindrocladium spathiphylli em espatifilo

Visconti, Alexandre; Bettiol, Wagner; Morandi, Marcelo Augusto Boechat
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 298-308
POR
Relevância na Pesquisa
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Fish hydrolyzed (HP), poultry manure (CF), shrimp skin (CC), cattle manure (EB), sewage sludge (LE) and castorbean presscake (TM) were evaluated for their effect of aqueous extracts with and without autoclaving, on mycelial growth and conidial germination of Cylindrocladium spathiphylli. The effect of mixtures of residues with potting mixes and their volatile compounds were also evaluated on the mycelial growth of the pathogen. To evaluate the effect of HP in the suppressiveness to Cylindrocladium spathiphylli, HP was added in potting mix artificially infested, at concentrations of 0, 10, 20, 30, 40 and 50% of the volume of water required to reach the water retention capacity of the potting mix. The mixtures were incubated for 10 days and transferred to pots containing one plug of Spathiphyllum Opal per pot. In the experiments in vitro, aqueous extracts and mixtures containing HP showed the highest suppressiveness against the pathogen. In the Spathiphyllum growing, the suppressiveness occurred at concentrations higher than 20% of fish hidrolyzed.

Fontes de matéria orgânica para inibição de fitopatógenos habitantes do solo

Visconti, Alexandre
Fonte: Universidade Estadual Paulista (UNESP) Publicador: Universidade Estadual Paulista (UNESP)
Tipo: Dissertação de Mestrado Formato: vii, 61 f. : il., gráfs, tabs.
POR
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27.63%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Pós-graduação em Agronomia (Proteção de Plantas) - FCA; Podridões radiculares e murchas, causadas respectivamente por Cylindrocladium spathiphylli e Verticillium dahliae, podem inviabilizar a produção comercial de espatifilo e da berinjela. Com o reconhecido potencial de fontes de carbono na indução de supressividade de solos e de substratos a diversos patógenos habitantes do solo, o presente trabalho teve como objetivos: 1) avaliar o potencial de seis fontes de carbono (esterco bovino de curral, cama de frango, torta de mamona, casca de camarão, hidrolisado de peixe e lodo de esgoto compostado) na inibição do crescimento micelial de C. spathiphylli; 2) avaliar o potencial de hidrolisado de peixe e cama de frango na indução de supressividade de substrato a C. spathiphylli; e 3) avaliar o efeito do hidrolisado de peixe no controle da murcha de verticilio em berinjela e no desenvolvimento das plantas. Para avaliar a inibição do crescimento micelial de C. spathiphylli, extratos aquosos das matérias orgânicas foram incorporados ao meio BDA nas concentrações de 0, 5, 10, 15, 20, 25 e 30% (v/v) Além disso, ao substrato padrão para espatifilo foram incorporados as matérias orgânicas nas concentrações de 0...

Induction of suppressiveness to Fusarium wilt of chrysanthemum with composted sewage sludge

Pinto, Zayame Vegette; Morandi, Marcelo Augusto Boechat; Bettiol, Wagner
Fonte: Sociedade Brasileira de Fitopatologia Publicador: Sociedade Brasileira de Fitopatologia
Tipo: Artigo de Revista Científica Formato: 414-422
ENG
Relevância na Pesquisa
27.3%
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); The effectiveness of composted sewage sludge incorporated into Pinus bark-based substrate with or without biofertilizer, fish hydrolyzate, chitosan and Trichoderma asperellum was evaluated for the control of Fusarium wilt in chrysanthemum. The substrate was obtained from pots containing chrysanthemum plants killed by the pathogen. Half of the substrate was sterilized prior to the incorporation of sewage sludge (0, 10%, 20% and 30% v/v). These substrates were or were not supplemented with the following: biofertilizer, fish hydrolyzate and Trichoderma. The mixtures were transferred to pots, and the chrysanthemum was transplanted. For all treatments, half of the plants were sprayed weekly with chitosan. Assessment of severity was performed on the 8th, 12th, 15th and 20th week after transplanting. In the 12th week, microbiological and chemical analysis of the substrate was performed. The incorporation of composted sewage sludge into the Pinus bark-based substrate significantly reduced Fusarium wilt, which was progressively decreased as the concentration of sewage sludge increased. The addition of biofertilizer, fish hydrolyzate, chitosan and Trichoderma had no effect on the disease. The microbial community was greater in non-disinfested substrates. The results indicate that suppressiveness is related to the interaction of chemical and microbiological factors.

Biotic and abiotic factors associated with soil suppressiveness to Rhizoctonia solani

Ghini,Raquel; Morandi,Marcelo Augusto Boechat
Fonte: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz" Publicador: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz"
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2006 EN
Relevância na Pesquisa
27.63%
Crop management may modify soil characteristics, and as a consequence, alter incidence of diseases caused by soilborne pathogens. This study evaluated the suppressiveness to R. solani in 59 soil samples from a microbasin. Soil sampling areas included undisturbed forest, pasture and fallow ground areas, annual crops, perennial crops, and ploughed soil. The soil samples were characterized according to abiotic variables (pH; electrical conductivity; organic matter content; N total; P; K; Ca; Mg; Al; H; S; Na; Fe; Mn; Cu; Zn; B; cation exchange capacity; sum of bases and base saturation) and biotic variables (total microbial activity evaluated by the CO2 evolution and fluorescein diacetate hydrolysis; culturable bacterial, fungal, actinomycetes, protozoa, fluorescent Pseudomonas and Fusarium spp. communities). The contribution and relationships of these variables to suppression to R. solani were assessed by path analysis. When all samples were analyzed together, only abiotic variables correlated with suppression of R. solani, but the entire set of variables explained only 51% of the total variation. However, when samples were grouped and analyzed by vegetation cover, the set of evaluated variables in all cases accounted for more than 90% of the variation in suppression of the pathogen. In highly suppressive soils of forest and pasture/fallow ground areas...

Induction of suppressiveness to Fusarium wilt of chrysanthemum with composted sewage sludge

Pinto,Zayame Vegette; Morandi,Marcelo Augusto Boechat; Bettiol,Wagner
Fonte: Sociedade Brasileira de Fitopatologia Publicador: Sociedade Brasileira de Fitopatologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2013 EN
Relevância na Pesquisa
27.3%
The effectiveness of composted sewage sludge incorporated into Pinus bark-based substrate with or without biofertilizer, fish hydrolyzate, chitosan and Trichoderma asperellum was evaluated for the control of Fusarium wilt in chrysanthemum. The substrate was obtained from pots containing chrysanthemum plants killed by the pathogen. Half of the substrate was sterilized prior to the incorporation of sewage sludge (0, 10%, 20% and 30% v/v). These substrates were or were not supplemented with the following: biofertilizer, fish hydrolyzate and Trichoderma. The mixtures were transferred to pots, and the chrysanthemum was transplanted. For all treatments, half of the plants were sprayed weekly with chitosan. Assessment of severity was performed on the 8th, 12th, 15th and 20th week after transplanting. In the 12th week, microbiological and chemical analysis of the substrate was performed. The incorporation of composted sewage sludge into the Pinus bark-based substrate significantly reduced Fusarium wilt, which was progressively decreased as the concentration of sewage sludge increased. The addition of biofertilizer, fish hydrolyzate, chitosan and Trichoderma had no effect on the disease. The microbial community was greater in non-disinfested substrates. The results indicate that suppressiveness is related to the interaction of chemical and microbiological factors.

Bacterial rRNA Genes Associated with Soil Suppressiveness against the Plant-Parasitic Nematode Heterodera schachtii

Yin, Bei; Valinsky, Lea; Gao, Xuebiao; Becker, J. Ole; Borneman, James
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /03/2003 EN
Relevância na Pesquisa
28.21%
The goal of this study was to identify bacteria involved in soil suppressiveness against the plant-parasitic nematode Heterodera schachtii. Since H. schachtii cysts isolated from the suppressive soil can transfer this beneficial property to nonsuppressive soils, analysis of the cyst-associated microorganisms should lead to the identification of the causal organisms. Our experimental approach was to identify bacterial rRNA genes (rDNA) associated with H. schachtii cysts obtained from soil mixtures with various levels of suppressiveness. We hypothesized that we would be able to identify bacteria involved in the suppressiveness by correlating population shifts with differing levels of suppressiveness. Soil treatments containing different amounts of suppressive and fumigation-induced nonsuppressive soils exhibited various levels of suppressiveness after two nematode generations. The 10%-suppressive-soil treatment contained numbers of eggs per gram of soil similar to those of the 100%-suppressive-soil treatment, indicating that the suppressive factor(s) had been transferred. Bacterial rDNA associated with H. schachtii cysts were identified using a culture-independent method termed oligonucleotide fingerprinting of rRNA genes. Bacteria from five major taxonomic groups (Actinobacteria...

Yeast mitochondrial genomes consisting of only A.T base pairs replicate and exhibit suppressiveness.

Fangman, W L; Dujon, B
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /11/1984 EN
Relevância na Pesquisa
27.63%
Mutants, called p-, that result from extensive deletions of the 75-kilobase Saccharomyces cerevisiae mitochondrial genome arise at high frequency. The remaining mitochondrial DNA is amplified in the p- cells, often as head-to-tail multimers, producing a cell with the normal amount of mitochondrial DNA. In matings, some of these p- mutants exhibit zygotic hypersuppressiveness, excluding the wild-type mitochondrial genome (p+) from all the diploids that are produced. From a hypersuppressive p- strain, we isolated two mutants with reduced suppressiveness. These mutants, one moderately suppressive and one nonsuppressive, retain only 89 and 70 base pairs, respectively, of the wild-type mitochondrial genome. Their sequences consist of 100% A . T base pairs. Replication of DNA in the mitochondrion, formation and amplification of new deletion genomes, and exhibition of suppressiveness do not require a single G . C base pair.

Microbial Properties of Composts That Suppress Damping-Off and Root Rot of Creeping Bentgrass Caused by Pythium graminicola

Craft, C. M.; Nelson, E. B.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /05/1996 EN
Relevância na Pesquisa
17.84%
Composts prepared from a variety of feedstocks were tested for their ability to suppress seedling and root diseases of creeping bentgrass caused by Pythium graminicola. Among the most suppressive materials in laboratory experiments were different batches of a brewery sludge compost and a biosolids compost from Endicott, N.Y. Batches of these composts that were initially not suppressive to Pythium damping-off became more suppressive with increasing compost age. Leaf, yard waste, food, and spent mushroom composts as well as certain biosolids, cow manure, chicken-cow manure, and leaf-chicken manure composts were not suppressive to Pythium damping-off. In some cases, turkey litter, chicken manure, chicken-leaf, and food waste composts were inhibitory to creeping bentgrass seed germination in laboratory experiments. Microbial populations varied among all of the composts tested. Bacterial populations were high in all composts except the turkey litter compost, in which populations were 1,000- to 10,000-fold lower than in the other composts tested. Among the highest populations of heterotrophic fungi and antibiotic-producing actinomycetes were those found in all batches of the brewery sludge compost, whereas the lowest populations were found in turkey litter...

Persistence and Suppressiveness of Pasteuria penetrans to Meloidogyne arenaria Race

Cetintas, R.; Dickson, D. W.
Fonte: Society of Nematologists Publicador: Society of Nematologists
Tipo: Artigo de Revista Científica
Publicado em /12/2004 EN
Relevância na Pesquisa
27.63%
The long-term persistence and suppressiveness of Pasteuria penetrans against Meloidogyne arenaria race 1 were investigated in a formerly root-knot nematode suppressive site following 9 years of continuous cultivation of three treatments and 4 years of continuous peanut. The three treatments were two M. arenaria race 1 nonhost crops, bahiagrass (Paspalum notatum cv. Pensacola var. Tifton 9), rhizomal peanut (Arachis glabrata cv. Florigraze), and weed fallow. Two root-knot nematode susceptible weeds commonly observed in weed fallow plots were hairy indigo (Indigofera hirsuta) and alyce clover (Alysicarpus vaginalis). The percentage of J2 with endospores attached reached the highest level of 87% in 2000 in weed fallow, and 63% and 53% in 2002 in bahiagrass and rhizomal peanut, respectively. The percentage of endospore-filled females extracted from peanut roots grown in weed fallow plots increased from nondetectable in 1999 to 56% in 2002, whereas the percentages in bahiagrass and rhizomal peanut plots were 41% and 16%, respectively. Over 4 years, however, there was no strong evidence that endospores densities reached suppressive levels because peanut roots, pods, and pegs were heavily galled, and yields were suppressed. This might be attributed to the discovery of M. javanica infecting peanut in this field in early autumn 2001. A laboratory test confirmed that although the P. penetrans isolate specific to M. arenaria attached to M. javanica J2...

Detection and Description of Soils with Specific Nematode Suppressiveness

Westphal, Andreas
Fonte: Society of Nematologists Publicador: Society of Nematologists
Tipo: Artigo de Revista Científica
Publicado em /03/2005 EN
Relevância na Pesquisa
28.15%
Soils with specific suppressiveness to plant-parasitic nematodes are of interest to define the mechanisms that regulate population density. Suppressive soils prevent nematodes from establishing and from causing disease, and they diminish disease severity after initial nematode damage in continuous culturing of a host. A range of non-specific and specific soil treatments, followed by infestation with a target nematode, have been employed to identify nematode-suppressive soils. Biocidal treatments, soil transfer tests, and baiting approaches together with observations of the plant-parasitic nematode in the root zone of susceptible host plants have improved the understanding of nematode-suppressive soils. Techniques to demonstrate specific soil suppressiveness against plant-parasitic nematodes are compared in this review. The overlap of studies on soil suppressiveness with recent advances in soil health and quality is briefly discussed. The emphasis is on methods (or criteria) used to detect and identify soils that maintain specific soil suppressiveness to plant-parasitic nematodes. While biocidal treatments can detect general and specific soil suppressiveness, soil transfer studies, by definition, apply only to specific soil suppressiveness. Finally...

Factors associated with the suppressiveness of sugarcane soils to plant-parasitic nematodes

Stirling, Graham R.; Rames, Emily; Stirling, A. Marcelle; Hamill, Sharon
Fonte: The Society of Nematologists Publicador: The Society of Nematologists
Tipo: Artigo de Revista Científica
Publicado em //2011 EN
Relevância na Pesquisa
27.63%
Observations in three Australian sugarcane fields suggested that the soil just under the trash blanket (the covering of crop residue that remains on the soil surface after crops are harvested) was suppressive to plant-parasitic nematodes. Roots were concentrated in this upper layer of soil but plant-parasitic nematode populations were relatively low and roots showed few signs of nematode damage. Root biomass was much lower 15 cm further down the soil profile, where root health was poor and populations of plant-parasitic nematodes were 3-5 times higher than near the soil surface. A bioassay in which Radopholus similis (a nematode that does not occur in sugarcane soils) was inoculated into heat-sterilized and untreated soils, confirmed that biological factors were limiting nematode populations in some of the soils, with soil from 0-2 cm much more suppressive than soil from 15-17 cm. Surface soil from one site was highly suppressive, as only 16% of R. similis recoverable from heated soil were retrieved from this soil after 8 days. Numerous soil chemical, biochemical, and biological properties were measured, and non-linear regression analysis identified two major groups of factors that were significantly associated with suppressiveness. One group reflected the amount of organic matter in soil (total C...

Chitin Amendment Increases Soil Suppressiveness toward Plant Pathogens and Modulates the Actinobacterial and Oxalobacteraceal Communities in an Experimental Agricultural Field

Cretoiu, Mariana Silvia; Korthals, Gerard W.; Visser, Johnny H. M.; van Elsas, Jan Dirk
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /09/2013 EN
Relevância na Pesquisa
27.63%
A long-term experiment on the effect of chitin addition to soil on the suppression of soilborne pathogens was set up and monitored for 8 years in an experimental field, Vredepeel, The Netherlands. Chitinous matter obtained from shrimps was added to soil top layers on two different occasions, and the suppressiveness of soil toward Verticillium dahliae, as well as plant-pathogenic nematodes, was assessed, in addition to analyses of the abundances and community structures of members of the soil microbiota. The data revealed that chitin amendment had raised the suppressiveness of soil, in particular toward Verticillium dahliae, 9 months after the (second) treatment, extending to 2 years following treatment. Moreover, major effects of the added chitin on the soil microbial communities were detected. First, shifts in both the abundances and structures of the chitin-treated soil microbial communities, both of total soil bacteria and fungi, were found. In addition, the abundances and structures of soil actinobacteria and the Oxalobacteraceae were affected by chitin. At the functional gene level, the abundance of specific (family-18 glycoside hydrolase) chitinase genes carried by the soil bacteria also revealed upshifts as a result of the added chitin. The effects of chitin noted for the Oxalobacteraceae were specifically related to significant upshifts in the abundances of the species Duganella violaceinigra and Massilia plicata. These effects of chitin persisted over the time of the experiment.

Bioorganic Fertilizer Enhances Soil Suppressive Capacity against Bacterial Wilt of Tomato

Liu, Lijuan; Sun, Chengliang; Liu, Shuangri; Chai, Rushan; Huang, Weiqing; Liu, Xingxing; Tang, Caixian; Zhang, Yongsong
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 01/04/2015 EN
Relevância na Pesquisa
17.84%
Tomato bacterial wilt caused by Ralstonia solanacearum is one of the most destructive soil-borne diseases. Many strategies have been taken to improve soil suppressiveness against this destructive disease, but limited success has been achieved. In this study, a novel bioorganic fertilizer revealed a higher suppressive ability against bacterial wilt compared with several soil management methods in the field over four growing seasons from March 2011 to July 2013. The application of the bioorganic fertilizer significantly (P<0.05) reduced disease incidence of tomato and increased fruit yields in four independent trials. The association among the level of disease incidence, soil physicochemical and biological properties was investigated. The soil treated with the bioorganic fertilizer increased soil pH value, electric conductivity, organic carbon, NH4+-N, NO3--N and available K content, microbial activities and microbial biomass carbon content, which were positively related with soil suppressiveness. Bacterial and actinomycete populations assessed using classical plate counts were highest, whereas R. solanacearum and fungal populations were lowest in soil applied with the bioorganic fertilizer. Microbial community diversity and richness were assessed using denaturing gel gradient electrophoresis profile analysis. The soil treated with the bioorganic fertilizer exhibited higher bacterial community diversity but lower fungal community diversity. Redundancy analysis showed that bacterial community diversity and richness negatively related with bacterial wilt suppressiveness...

Fatores envolvidos na supressividade de Meloidogyne exigua em cafeeiro: nova técnica para análise de compostos voláteis tóxicos a fitonematoides; Factors involved in suppressiveness of meloidogyne exigua in coffee: new technique for analysis of volatile toxic to nematodes

Fonte: UNIVERSIDADE FEDERAL DE LAVRAS; DFP - Programa de Pós-graduação; UFLA; BRASIL Publicador: UNIVERSIDADE FEDERAL DE LAVRAS; DFP - Programa de Pós-graduação; UFLA; BRASIL
Tipo: Tese de Doutorado
PT_BR
Relevância na Pesquisa
27.3%

Perspectivas de supressividade e qualidade do inóculo rizosférico de Meloidogyne exigua no cafeeiro em alguns períodos do ano; Perspectives of suppressiveness of meloidogyne exigua rhizosphere inoculum on coffee in some periods of the year

Fonte: UNIVERSIDADE FEDERAL DE LAVRAS; DFP - Programa de Pós-graduação; UFLA; BRASIL Publicador: UNIVERSIDADE FEDERAL DE LAVRAS; DFP - Programa de Pós-graduação; UFLA; BRASIL
Tipo: Dissertação
PT_BR
Relevância na Pesquisa
27.3%

Propiedades emergentes a nivel de comunidad como guía en el manejo de la salud de las raíces de los cultivos en agroecosistemas; Emergent community properties as a basis for the management of crop root health in agroecosystems

García Espinosa, Roberto
Fonte: Murcia: servicio de publicaciones de la Universidad de Murcia Publicador: Murcia: servicio de publicaciones de la Universidad de Murcia
Tipo: Artigo de Revista Científica Formato: application/pdf
SPA
Relevância na Pesquisa
17.84%
La supresividad de suelos, surge como el concepto central en la detección de propiedades emergentes del nivel comunidad con relación a enfermedades con origen en el suelo en agroecosistemas. En este escrito, se explica la naturaleza de la supresividad. Se describen algunos trabajos realizados en México sobre caracterización de suelos supresores, y de inducción de supresividad en agroecosistemas fuera de balance. Se describen los trabajos de inducción de supresividad a Phytophthora cinnamomi en aguacatero que dieron origen al sistema Colegio de Postgraduados de manejo de esta enfermedad. Se describe también el trabajo de inducción de supresividad a enfermedades de la raíz del maíz en agroecosistemas tropicales mediante la rotación con la leguminosa tropical Mucuna deeringiana, y se concluye con la descripción del establecimiento de complejidad ascendente de antagonistas (a patógenos), aislados de suelos supresores, en los sustratos de germinación para la protección de plantas de jitomate a fitopatógenos del suelo. Finalmente se valoran algunas perspectivas de investigación sobre este tema en México.; ABSTRACT Soil suppressiveness could be considered as the central concept emerging from community level in regard to soil-borne diseases in agroecosystems. In this paper the nature of soil suppressiveness is described as well as some research conducted in Mexico characterizing suppressive soils and the induction of such property in conducive soils. The induction of soil suppressiveness to Phytophthora cinnamomi in avocado groves that yielded the so called Colegio de Postgraduados integrated management system is also described. The emergence of soil suppressiveness to corn root diseases under tropical conditions through the rotation with the tropical legume Mucuna deeringiana is also described and an account is made of the establishment of ascendant complexity of antagonistic (to plant pathogens) microorganisms isolated from suppressive soils to protect tomato plantlets to some root pathogens. Finally...

Mitochondrial Genetics in Bakers' Yeast: A Molecular Mechanism for Recombinational Polarity and Suppressiveness

Perlman, Philip S.; Birky, C. William
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /11/1974 EN
Relevância na Pesquisa
27.3%
Recombinational polarity and suppressiveness are two well-known but puzzling cytoplasmic genetic phenomena in bakers' yeast, Saccharomyces cerevisiae. Little progress has been made in characterizing the underlying molecular mechanisms of these phenomena. In this paper we describe a molecular model for recombinational polarity that is compatible with the available genetic evidence. The model stresses the role of small deletions and excision/repair processes in otherwise canonical recombinational events. According to the model, both phenomena require recombination and may share mechanistic elements.

Avaliação da supressividade do solo a Thielaviopsis sp.; Evaluation to soil suppressiveness to Thielaviopsis sp.

Pereira, Priscilla de Fátima
Fonte: Universidade Federal de Lavras; Programa de Pós-Graduação em Agronomia/Fitopatologia; UFLA; brasil; Departamento de Fitopatologia Publicador: Universidade Federal de Lavras; Programa de Pós-Graduação em Agronomia/Fitopatologia; UFLA; brasil; Departamento de Fitopatologia
Tipo: Dissertação
Publicado em 16/12/2015 POR
Relevância na Pesquisa
37.84%
The stem-bleeding caused by Thielaviopsis sp. has became cause of extreme concern for farmers, research institutions, technical assistance agencies, and health protection and monitoring agencies. This disease has been spreading and, thus, increasing the quantity of coconut trees and farms affected each year. The search for a sustainable control of this pathogen has become constant over time. In this study, we aimed to evaluate the suppressiveness and / or conduciveness of coconut planting soils of two Brazilian regions, as well as the possible variables responsible for such suppression and / or conduciveness. The influence of soils on Thielaviopsis sp. population was assessed by estimating the percentage of baits of ripe banana colonized by this pathogen on soils. This colonization percentage ranged from 4.61 to 83,08%. Then, based on the Scott Knott means test, samples of five most suppressive soils, and five most conducive soils were collected to estimate their nature, as well as determining factors for suppressiveness and / or conduciveness. Physical, chemical and biological characters were assessed for each sample. The total bacteria parameter was found to be higher in suppressive soils. Fluorescent Pseudomonas was only found in one type of soil. The pH...

Fatores bióticos e abióticos associados à supressividade de solos a Rhizoctonia solani; Biotic and abiotic factors associated with soil suppressiveness to Rhizoctonia solani

Ghini, Raquel; Morandi, Marcelo Augusto Boechat
Fonte: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz Publicador: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; Formato: application/pdf
Publicado em 01/04/2006 ENG
Relevância na Pesquisa
27.63%
Crop management may modify soil characteristics, and as a consequence, alter incidence of diseases caused by soilborne pathogens. This study evaluated the suppressiveness to R. solani in 59 soil samples from a microbasin. Soil sampling areas included undisturbed forest, pasture and fallow ground areas, annual crops, perennial crops, and ploughed soil. The soil samples were characterized according to abiotic variables (pH; electrical conductivity; organic matter content; N total; P; K; Ca; Mg; Al; H; S; Na; Fe; Mn; Cu; Zn; B; cation exchange capacity; sum of bases and base saturation) and biotic variables (total microbial activity evaluated by the CO2 evolution and fluorescein diacetate hydrolysis; culturable bacterial, fungal, actinomycetes, protozoa, fluorescent Pseudomonas and Fusarium spp. communities). The contribution and relationships of these variables to suppression to R. solani were assessed by path analysis. When all samples were analyzed together, only abiotic variables correlated with suppression of R. solani, but the entire set of variables explained only 51% of the total variation. However, when samples were grouped and analyzed by vegetation cover, the set of evaluated variables in all cases accounted for more than 90% of the variation in suppression of the pathogen. In highly suppressive soils of forest and pasture/fallow ground areas...