Resumo: O solo é um ecossistema caracterizado pela grande complexidade de difícil estudo, devido à sua heterogeneidade, especialmente os microrganismos do solo. Atualmente, ferramentas da biologia molecular têm sido usadas para mostrar o potencial biotecnológico do solo, através dos genes microbianos. A extração direta do DNA é uma etapa importante nesse tipo de estudo, porém, continua sendo um obstáculo para a avaliação da diversidade microbiana do solo. Esses estudos no Brasil apresentam algumas dificuldades, uma vez que a maioria das técnicas foi desenvolvida para solos de clima temperado. Desta forma, o objetivo deste estudo foi avaliar dez diferentes técnicas para extração direta de DNA de solos em áreas de cultura de cana-de-açúcar sob manejo orgânico e convencional. A eletroforese se apresentou como a técnica mais adequada para se conhecer a eficiência da extração do DNA, através da intensidade e tamanho de suas bandas. A técnica de Selbach (SEL) apresentou melhores resultados, com bandas de DNA mais intensas e sem arraste, indicando a obtenção de uma solução com menores teores de contaminantes. Com a técnica de Direito (DIR) também se verificou bandas de DNA, porém menos fortes e sem arraste. A técnica proposta neste estudo (PRO) resultou em bandas de DNA fortes, porém com arraste, indicando a necessidade de uma etapa para purificação do DNA extraído. Esta mostrou ser a metodologia de mais fácil e rápida execução, sendo que, após processo de purificação a região 16S do DNA ribossomal, utilizando-se primers universais, foi amplificada satisfatoriamente a partir do DNA obtido do solo. Bandas de DNA apresentadas na eletroforese a partir das amostras de solo sob viii manejo orgânico foram mais intensas do que aquelas de manejo convencional. Estes resultados estão relacionados com a maior quantidade de biomassa microbiana presente no solo orgânico... (Resumo completo, clicar acesso eletrônico abaixo). / Abstract: Soil is an ecosystem characterized by a great complexity and hard to study due to its heterogeneity, especially the soil microorganisms. Nowadays, molecular biology tools have been used to show the biotechnological potential of the soil mainly through microbial genes. Direct extraction of DNA from soil is an important step in this kind of study, however it is still an obstacle for microbial diversity evaluation. Besides, the majority of techniques proposed was developed for soils from temperate climate. This work aimed to evaluate ten different techniques for soil direct DNA extraction from sugar cane crop areas under organic and conventional managements, which presented distinct results. Gel electrophoresis was the most appropriate technique to evaluate the efficiency of DNA extraction, through the intensity and size of the bands. The Selbach technique (SEL) showed the best results, with more intense DNA bands and without smearing , indicating that a DNA solution with low concentration of contaminants was obtained. With the Direito technique (DIR) DNA bands were also verified, but less intensive and also without smearing. The technique proposed in this study (PRO) resulted in intense DNA however with smearing, indicating that a DNA purification step is necessary. This technique was easy, cheap and rapid to execute, enabling the amplification of 16S rDNA (using universal primers) after DNA solution purification. The intensity of DNA bands, as revealed by electrophoresis, was higher when using DNA solution extracted from soil under organic management, which also presented higher microbial biomass. This study is a contribuition for the selection and improvement of molecular tools to the study of microbial diversity applied to Brazilian soils. / Orientador: Sâmia Maria Tauk-Tornisielo / Coorientador: Sandra Regina Ceccato-Antonini / Banca: Marli de Fatima Fiore / Banca: Welington Luiz de Araujo / Mestre

Os modelos orgânicos de produção despontam como uma alternativa à agricultura convencional, entretanto, a falta de conhecimento para o processo ainda é uma grande lacuna. O objetivo deste trabalho foi testar o efeito da adoção gradual de insumos e práticas agronômicas mais ecológicas, até a total substituição por procedimentos permitidos pelas normas da produção orgânica (TRANS) na cultura dos citros. A comparação foi feita em área equivalente e contígua onde o manejo convencional da propriedade foi mantido (CONV). O ensaio foi conduzido por 5 anos dentro de uma quadra de produção comercial de citros. Para o presente estudo foram avaliadas as três últimas safras, sendo 2013/2014, 2014/2015 e 2015/2016. As variáveis de solo foram analisadas em duas profundidades (00-20 e 20-50 cm) e foram avaliados dados de: microbiologia do solo (qPCR e T-RFLP de bactérias e fungos, CBMS, qCO2, qMIC, micorrìza e glomalina); física de solo (dados de Curva de Retenção e agregados estáveis) e; fertilidade do solo. Das variáveis de planta foram avaliadas: teor de nutrientes foliares, produtividade e índice \"ratio\" do suco. As comparações e as interações das variáveis no conjunto de respostas do ensaio foram analisadas pelo teste t de Student, Análise de Componentes Principais e Análises de Coordenadas Principais. O conjunto das variáveis de solo e planta mostraram melhores respostas no tratamento TRANS nas safras 13/14 e 14/15, convergindo com os melhores resultados de produtividade. Na safra 15/16 a resposta na nutrição das plantas, particularmente em N, Mn e Zn, não foram capazes de manter a produtividade nos mesmos patamares do CONV. A comunidade de bactérias e fungos do solo estruturaram-se de forma distinta na safra 13/14, em resposta ao manejo do tratamento TRANS e ao menor volume de chuva, e foram muito próximas nas safras 14/15 e 15/16, períodos mais chuvosos. Os dados trazem vários indicativos para subsidiar práticas agronômicas voltadas à transição para a citricultura orgânica e sustentável. / The organic agriculture systems appear as an alternative to conventional agriculture. However, the lack of knowledge to proceed the transition is still a big gap. The aim of this work was to test the effect of gradual adoption of ecological inputs and agronomic practices, up to total substitution for techniques allowed by organic agriculture rules (TRANS), in the citrus cultivation. The TRANS plots were compared with an equivalent and adjacent area, where the farmer conventional management was maintained (CONV). The experiment was carried out for five years inside a commercial orchard. For this work, the last three crops years were assessed: 2013/2014, 2014/2015 e 2015/2016. The variables were evaluated at two depths (00-20 and 20- 50 cm) and the following analysis were performed: soil microbiology (bacteria and fungi qPCR and T-RFLP, MBC, qCO2, qMIC, mycorrhizal fungi and glomalines); soil physics (data of water retention curve and stable aggregates); and soil fertility. From the plant variable: foliar nutrient content; fruits production and juice ratio index were evaluated. The results and interactions of the all variables were compared applying Student t test, Principal Components Analysis (PCA) and Principal Coordinates Analysis (PCoA). In general, the set of soil and plant variables shows the best responses in the TRANS plots, in the 13/14 and 14/15 crop years, and it matched with the best harvest results. In the 15/16 crop year, the plant nutrition responses, particularly N, Mn and Zn, was not capable to maintain the same levels of CONV plots fruits production. The structure of soil bacteria and fungi community shaped in different way, between treatments, in the 13/14 crop year, responding to the changes from TRANS and lower amount of rainfall. These structures were close to similar in the 14/15 and 15/16 crop years, when the amount of rainfall was higher. The data bring forward several indications to assist agronomical practices toward a transition to organic and sustainable citrus cropping.

Submitted by (lucia.rodrigues@ufrpe.br) on 2016-06-29T14:03:23Z No. of bitstreams: 1 Anibia Vicente da Silva.pdf: 1124619 bytes, checksum: 3937e390506d1c9bb8bda42364a17869 (MD5) / Made available in DSpace on 2016-06-29T14:03:23Z (GMT). No. of bitstreams: 1 Anibia Vicente da Silva.pdf: 1124619 bytes, checksum: 3937e390506d1c9bb8bda42364a17869 (MD5) Previous issue date: 2013-05-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Gliricidia sepium, Jacq., Kunth, Walp. is a medium-sized tree belonging to the Leguminosae family, and has great importance for the commercial area, due to its multiple use characteristics. Many leguminous trees, such as gliricidia, are able to form symbiosis with nitrogen-fixing bacteria (NFB) and arbuscular mycorrhizal fungi (AMF), which promote better absorption of nutrients. The BNF is a highly dependent energy process in ATP form. AMF activity therefore benefits this process because these microorganisms promote greater P uptake by plants. Plant growth promoting bacteria (PGPB’s) also can contribute to this process in them they are also able to solubilize phosphates. In this context, the work aimed to evaluate gliricidia’s nodulation and symbiotic efficiency by triple inoculation of PGPB’s - rhizobia - AMF, aiming to optimize BNF process. The experiment was performed in a greenhouse in randomized block design with 11 x 2 (+1) factorial arrangement. The 11 levels corresponded the inoculation of 10 PGPB's jointly inoculated with rhizobia and a rhizobia treatment independently - in presence and absence of AMF -, plus a control (control - no PGPB, AMF or rhizobia). Pots filled with 8 kg of soil (dystrophic Ultisol) were used as experimental unit. In the sowing was done the Rhizobium sp. (BR 8801) inoculation and co-inoculation with AMF + BPCP's. 10 days after sowing (DAS) re-inoculation was performed with Rhizobium sp. During plant growth, a nutrient solution without addition of nitrogen and phosphorus was used. The variables evaluated were: plant height (PH) at 30, 60, 90 and 120 DAS, shoot dry matter (SDM), root (RDM) and nodules (NDM); RDM / SDM ratio; root length (RL), total N accumulated (Nac) in SDM; phosphorus rate in SDM; efficiency of strain (E), phosphorus rate (P), P contents and mycorrhizal colonization (MC). Treatments showed significant effects for all variables. AMF addition in treatments promoted better results for the evaluated variables, observing significant difference (p <0.05) for treatments with co-inoculation of BPCP's and no significant difference (p>0.05) for treatment inoculated with Rhizobium (BR 8801), in presence or absence of AMF. BR 8801+EL-183+AMF treatment promoted the best response for gliricidia / A Gliricidia sepium, Jacq., Kunth, Walp é uma árvore de porte médio, pertencente à família Leguminosae, que possui grande importância para a área comercial, devido as suas características de uso múltiplo. Muitas leguminosas arbóreas, tais como a gliricídia, são capazes de formar simbiose com bactérias fixadoras de nitrogênio (BFN) e fungos micorrízicos arbusculares (FMA) que promovem maior absorção de nutrientes. A fixação biológica de nitrogênio (FBN) é um processo altamente dependente de energia na forma de ATP. Portanto, a atividade dos FMAs beneficia esse processo por promoverem maior absorção de P pelas plantas. As bactérias promotoras de crescimento de plantas (BPCPs) também podem contribuir para esse processo visto que também são capazes de solubilizar fosfatos. Nesse contexto, o presente trabalho teve como objetivo avaliar a nodulação e eficiência simbiótica da gliricidia pela tripla inoculação BPCPs - rizóbios - FMA, visando otimizar o processo da FBN. O experimento foi conduzido em casa de vegetação, com delineamento em blocos ao acaso, em arranjo fatorial 11 x 2 (+1). Os 11 (onze) níveis corresponderam à inoculação de 10 BPCP’s inoculadas conjuntamente com rizóbio e um tratamento somente com rizóbio - na presença e ausência de FMA -, além de uma testemunha absoluta (controle - sem BPCP, FMA e rizóbio). Foram utilizados vasos preenchidos com 8 kg de solo (Argissolo Vermelho Amarelo distrófico) como unidade experimental. Na semeadura foi efetuada a inoculação com Rhizobium sp. (BR 8801) e co-inoculação com BPCP’s + FMA. Aos 10 (dez) dias após o plantio (DAP) foi realizada uma reinoculação com Rhizobium sp.. Durante o desenvolvimento das plantas foi utilizada solução nutritiva sem adição de nitrogênio e fósforo. As variáveis avaliadas foram: altura de planta (AP) aos 30, 60, 90 e 120 DAP; massa seca da parte aérea (MSPA), da raiz (MSR) e dos nódulos (MSN); relação MSR/MSPA; comprimento da raiz (CR); N total acumulado (Nac) na MSPA; teor de fósforo na MSPA; eficiência da estirpe (E), teor de fósforo (P), conteúdo de P e colonização micorrízica (CM). Os tratamentos demonstraram efeito significativo para todas as variáveis avaliadas. A adição de FMA aos tratamentos proporcionou melhores resultados para as variáveis estudadas, observando-se diferença significativa (p<0,05) para os tratamentos co-inoculados com BPCP’s e não significativa (p>0,05) para o tratamento inoculado com Rhizobium (BR 8801), na presença ou ausência de FMA. O tratamento BR 8801 + 183-EL + FMA promoveu a melhor resposta para a gliricídia

Magister Scientiae - MSc / A study of the microbial diversity in sediments of the Great Berg River estuary is carried out using modern molecular phylogenetic methods. The aim of this study was to determine the effect of (pollution by) the effluents of the fish industry on the composition of the microbial community in the sediments. The diversity in microbial groups of sediment samples that received wastewater from the local fishing industry was investigated by a PCR-DGGE (polymerase chain reaction-denaturing gradient gel electrophoresis) approach and compared to an unaffected site. / South Africa

No description available.

The soil microbial community has a major impact on ecosystem processes on a global scale. Anthropogenic stress has a significant effect on the composition, biomass and activity of the microbial community. In addition, this effect depends not only on the anthropogenic activity, but also on the environmental conditions. Modern analytical and molecular methods, including the use of biochemical markers, can be well used to monitor changes in the microbial community. These methods do not monitor the community directly, but detect the substances that are secreted and transformed by microbes and, last but not least, those that are part of them. The amount of these biochemical markers reflects the biomass, condition and taxonomic composition of a particular microbial community. In the presented work, these markers were used to monitor the response of microorganisms in various ecosystems which are affected directly or indirectly by human activity. The results of the dissertation are presented in four articles. Three of them have been published in international journals with IF and one is prepared in the form of a manuscript for publication. The first publication presents the results of research exploring the impact of traditional agriculture in Papua New Guinea on the soil microbial communities, soil...

In natural ecosystems, like deciduous and coniferous forests, soil CO2 flux or soil respiration is highly variable and influenced by multiple factors including temperature, precipitation, dissolved soil organic carbon (DOC), dissolved organic matter (DOM), and bacterial and fungal biomass and diversity. However, as the human population continues to grow rapidly, so too do urbanized landscapes with unknown consequences to soil respiration. To determine the extent urbanization influences seasonal shifts in microorganisms and environmental drivers alter soil respiration, we evaluated bacterial and fungal communities, soil physiochemical characteristics, and respiration in forested and urbanizing ecosystems in three watersheds across northern Utah, USA. Based on the next-generation sequencing of the 16s DNA and RNA, we found that montane bacteria were predominantly structured by season while urban bacteria were influenced by degree of urbanization. There was no apparent effect of season on montane fungi, but urban fungal communities followed patterns similar to urban bacterial communities. Bacterial diversity was sensitive to seasonality, especially in montane ecosystems, declining 21-34% from spring to summer and staying relatively low into fall, and fungal diversity was generally depressed in spring. Urban bacterial communities were differentiated by substantially more bacterial taxa with 62 unique OTUs within families structing phylogenetic differences compared with only 18 taxa differentiating montane communities. Similar to bacteria and fungi, DOC and ammonium concentrations fluctuated predominantly by season while these same parameters where highly variable among urban soils among the three watersheds. Structural components of DOM via parallel factor analysis (PARAFAC) of fluorescence excitation-emission matrices show varying patterns between montane and urban systems with humic substance resistance to biodegradability found more dominantly in montane systems. Incorporating all soil chemical parameters, daily temperature and moisture, and fungal and bacterial diversity and richness in mixed linear effects models describing daily CO2 over all seasons, we found that a single model best described montane soil respiration, while individual watershed models best described urban respiration. Montane respiration was related to the availability of DOC, different DOM components, and rRNA-based bacterial diversity . Alternatively, urban respiration was influenced by either bacterial diversity and richness in our rapidly urbanizing environment, DOM characteristics and soil O2 in the more agricultural urban soils, or the DOM parameter humification index (HIX) in highly urbanized soils. Our results suggest that urbanization creates distinct bacterial and fungal communities with a single soil biotic or chemical parameter structuring soil respiration, while montane ecosystems select for similar bacterial and fungal communities with respiration sensitive to fluctuations in soil moisture, bacteria and the recalcitrance of carbon (C) resources.

Sagebrush-dominated ecosystems are being transformed by wildfire, rangeland improvement techniques, and exotic plant invasions. These disturbances have substantial effects on the composition and structure of native vegetation, but the effects on ecosystem C and N dynamics are poorly understood. To examine whether differences in dominant vegetation affect the quantity and quality of plant organic matter inputs to soil, ecosystem C and N pools and rates of plant turnover were compared among historically grazed Wyoming big sagebrush, introduced perennial crested wheatgrass, and invasive annual cheatgrass communities. Since low soil moisture during the summer may inhibit the microbial colonization of plant detrital inputs and result in C-limitations to microbial growth, soils were treated with an in situ pulse of plant detritus prior to the onset of the summer dry-season, and rates of soil C and gross N cycling were compared between treated and untreated soils. Finally, because plant detritus is the dominant form of labile C input to soil microbes over a large portion of the year, the decomposition of 13C-labeled annual grass detritus was used to determine the importance of plant detritus versus soil organic matter as microbial substrate. Results revealed large differences in ecosystem C and N pools, and in the quantity of plant C and N inputs to soil among vegetation types, but differences in soil C and N cycling rates were more subtle. Plant biomass pools were greatest for sagebrush stands, but plant C and N inputs to soil were greatest in cheatgrass communities, such that rates of plant C and N turnover appeared to be accelerated in disturbed ecosystems. Earlier release of plant biomass to soil detrital pools stimulated N availability to a greater extent than C availability relative to untreated soils, and this effect could not be predicted from the C:N stoichiometry of plant detritus. Finally, in situ decomposition of cheatgrass detritus was rapid; however, there was no clear evidence of a time-lag during summer in microbial colonization of recently released plant detritus, and microbial consumption of plant detritus did not result in N-limitations to microbial growth.

No description available.

No description available.