As bactÃrias promotoras de crescimento em plantas (BPCP) representam uma parcela funcional ativa da biota do solo sÃo presentes na rizosfera no rizoplano e no interior de plantas hospedeiras O uso biotecnolÃgico dessas bactÃrias tem se intensificado nos Ãltimos anos O gÃnero Bacillus vem sendo continuamente citado em estudos relacionados a promoÃÃo de crescimento em espÃcies vegetais Algumas espÃcies podem ser aplicadas no tratamento de sementes, ÃrgÃos de propagaÃÃo vegetativa e mudas Diante disso o presente trabalho teve como objetivo avaliar a produÃÃo de biomassa de Bacillus sp (RAB9) com potencial uso na promoÃÃo de crescimento de mudas de bananeira A cepa Bacillus sp (RAB9) pertencente ao grupo das bactÃrias epifÃticas, foi isolada de rabanete proveniente da ColeÃÃo de Culturas do LaboratÃrio de Fitobacteriologia da Universidade Federal Rural de Pernambuco Os experimentos foram realizados em agitador orbital e em reator de bancada Em agitador orbital foi estudada a curva de crescimento da linhagem a 30ÂC para observar sua fase exponencial Para a produÃÃo de biomassa foram observados os efeitos da adiÃÃo do teor de peptona (5 a 50 g.L-1) no meio NYD (extrato de carne, extrato de levedura peptona de carne e dextrose) adiÃÃo de elementos secundÃrios (K2HPO4 e MgSO4) e fonte de nitrogÃnio inorgÃnico ((NH4)2SO4) Em reator de bancada foram realizados testes com diferentes vazÃes de ar em batelada simples bem como uma comparaÃÃo com batelada alimentada com o meio modificado As fermentaÃÃes nos reatores apresentaram formaÃÃo de espuma testes foram feitos com Ãleos vegetais (milho canola girassol soja) e mineral para verificaÃÃo do melhor antiespumante Posteriormente aos testes foram quantificadas a biomassa o aÃÃcar residual nitrogÃnio residual e nitrogÃnio amoniacal Com os resultados obtidos foi observado a importÃncia da adiÃÃo dos elementos (MgSO4 e (NH4)2SO4) ao meio NYD e da vazÃo de ar sobre o crescimento da cepa Com os parÃmetros estudados foram determinadas as melhores condiÃÃes para a produÃÃo de Bacillus sp RAB9 / The growth-promoting bacteria in plants (BPCP) represents a functional portion of the active biota soil rhizosphere are present in rhizoplane and within host plants The biotechnological use of these bacteria has intensified in recent years The genus Bacillus has been continually cited in studies related to growth promotion in plant species Some species can be applied as a seed treatment organs for the vegetative propagation and seedling Therefore this study aimed to assess the biomass of Bacillus sp (RAB9) with potential use in promoting growth of banana plantlets The strain Bacillus sp (RAB9) belonging to the group of epiphytic bacteria was isolated from radish from the Culture Collection of the Laboratory of Fitobacteriologia Federal Rural University of Pernambuco The experiments were performed on an orbital shaker and batch reactor In orbital shaker was studied growth curve of strain at 30ÂC to observe their exponential phase For the production of biomass were observed the effects of adding the content of peptone (5 to 50 g.L-1) in NYD medium (meat extract yeast extract meat peptone and dextrose) addition of secondary elements (K2HPO4 and MgSO4) and inorganic nitrogen source ((NH4)2SO4) In batch reactor tests were conducted with different air flows in simple batch and fed batch with a comparison with the modified medium The fermentations presented in the reactors foaming tests were made with vegetable oils (corn canola sunflower soybean) and to verify the best mineral defoamer Later tests were quantified biomass residual sugar residual nitrogen and ammonia nitrogen With the results noted the importance of the addition of elements (MgSO4 and (NH4)2SO4) in half NYD and air flow on the growth of strain With the studied parameters were determined the best conditions for the production of Bacillus sp RAB9

Submitted by Gabriela Lopes (gmachadolopesufpel@gmail.com) on 2017-07-05T14:00:51Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertação de Mestrado - Ester Schiavon Matoso.pdf: 3410407 bytes, checksum: 162df96e3e5a35b23543fd851dc17f78 (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2017-07-11T20:54:17Z (GMT) No. of bitstreams: 2 Dissertação de Mestrado - Ester Schiavon Matoso.pdf: 3410407 bytes, checksum: 162df96e3e5a35b23543fd851dc17f78 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-07-11T20:54:17Z (GMT). No. of bitstreams: 2 Dissertação de Mestrado - Ester Schiavon Matoso.pdf: 3410407 bytes, checksum: 162df96e3e5a35b23543fd851dc17f78 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-03-23 / A cana-de-açúcar é uma cultura de grande importância no Brasil, o país é o primeiro do mundo na produção de cana e açúcar, segundo em etanol e conquista, cada vez mais, o mercado externo com o uso do biocombustível como alternativa energética. Um dos problemas desta cultura é o plantio convencional, pois nele ocorre o gasto excessivo de colmos que poderiam ser destinados à indústria, além de aumentar o risco de difusão de pragas e doenças. Além disso, a cana-de-açúcar é extremamente dependente da adubação nitrogenada, pois entre os nutrientes responsáveis pela sua nutrição, o nitrogênio é o elemento absorvido em maior quantidade. Neste sentido, o objetivo deste trabalho foi avaliar os efeitos da inoculação de bactérias diazotróficas na produção de mudas originadas de minitoletes e de cultura de tecidos de cana-de-açúcar em substratos alternativos. Utilizaram-se as variedades de cana RB867515, RB92579, RB966928 e RB975932, e substratos produzidos a partir da mistura de casca de arroz carbonizada e composto orgânico, além de um de marca comercial. E foram desenvolvidos diversos experiementos, onde foram avaliados: a sobrevivência das espécies de bactérias diazotróficas nos substratos; parâmetros relacionados à brotação, desenvolvimento de parte aérea e de raízes, além do acúmulo de nitrogênio de mudas; a resposta dessas à inoculação quanto ao perfilhamento, teor de clorofila, área foliar, acúmulo de biomassa, incremento de massa seca, teor de nitrogênio e fixação biológica; e no cultivo in vitro foi aviada a multiplicação das brotações e o crescimento de plântulas em frascos contendo meio semissólido e em biorreator de imersão temporária, a resposta destas plantas à inoculação quanto ao enraizamento e a aclimatação nos diferentes substratos. Os resultados obtidos indicam a interação entre as variedades, substratos e inoculação para todos os parâmetros avaliados que envolveram estes fatores. Os substratos contendo casca de arroz carbonizada e composto orgânico apresentam melhores resultados na sobrevivência de bactérias diazotróficas e podem ser utilizados desde a aclimatação até o desenvolvimento de mudas. Todas as variedades apresentam excelente desenvolvimento de mudas a partir de micropropagação e também de minitoletes, e de alguma forma respondem à inoculação de bactérias diazotróficas, mas apesar disso, apenas na RB92579 e na RB975932 ocorreu a fixação biológica de nitrogênio / Sugarcane is a very important culture in Brazil, the country is the world's first in the production of cane and sugar, second of ethanol and increasingly conquers the foreign market with the use of biofuel as an alternative energy. One of the problems of this crop is conventional planting, because in it occurs the excessive spending of stalks that could be destined to the industry, besides increasing the risk of diffusion of plagues and diseases. Moreover, sugarcane is extremely dependent on nitrogen fertilization, because among the nutrients responsible for its nutrition, nitrogen is the element absorbed in greater quantity. In this sense, the objective of this work was to evaluate the effects of the inoculation of diazotrophic bacteria in the promotion of growth, rooting and biological nitrogen fixation of pre-sprouted and micropropagated sugarcane seedlings produced in alternative substrates. Were used the sugarcane varieties RB867515, RB92579, RB966928 and RB975932, and substrates produced from the mixture of carbonized rice rusk and organic compound, in addition to a trademark. And several experiments were developed, where they were evaluated: the survival of the diazotrophic bacteria species in the substrates; parameters related to sprouting, aerial part and root development, and nitrogen accumulation of seedlings; the response of these seedlings to inoculation for tillering, chlorophyll content, leaf area, biomass accumulation, dry mass increase, nitrogen content and biological fixation; And in the in vitro cultivation the multiplication of the shoots and the growth of seedlings in glass jars containing semi-solid medium and in temporary immersion bioreactor, the response of these plants to the inoculation in rooting and the acclimatization in the different substrates. The results indicate the interaction between the varieties, inoculation and substrates for all evaluated parameters that involved these factors. The substrates containing carbonized rice rusk and organic compost present better results in the survival of diazotrophic bacteria and can be used from acclimatization to the development of seedlings. All varieties show excellent development of seedlings from micropropagation and also minitoletes, and somehow respond to the inoculation of diazotrophic bacteria, but nevertheless, only in RB92579 and in RB975932 the biological fixation of nitrogen.

One of the major challenges for agricultural research in the 21st century is to increase crop productivity to meet the growing demand for food and feed. Biotic (e.g. plant pathogens) and abiotic stresses (e.g. soil salinity) have detrimental effects on agricultural productivity, with yield losses being as high as 60% for major crops such as barley, corn, potatoes, sorghum, soybean and wheat, especially in semi-arid regions such as Saudi Arabia. Plant growth promoting bacteria isolated from pioneer desert plants could serve as an eco-friendly, sustainable solution for improving plant growth, stress tolerance and health. In this dissertation, culture-independent amplicon sequencing of bacterial communities revealed how native desert plants influence their surrounding bacterial communities in a phylogeny-dependent manner. By culture-dependent isolation of the plant endosphere compartments and a number of bioassays, more than a hundred bacterial isolates with various biochemical properties, such as nutrient acquisition, hormone production and growth under stress conditions were obtained. From this collection, five phylogenetically diverse bacterial strains were able to promote the growth of the model plant Arabidopsis thaliana under salinity stress conditions in a common mechanism of inducing transcriptional changes of tissue-specific ion transporters and lowering Na+/K+ ratios in the shoots. By combining a number of in vitro bioassays, plant phenotyping and volatile-mediated inhibition assays with next-generation sequencing technology, gas chromatography–mass spectrometry and bioinformatics tools, a candidate strain was presented as a multi-stress tolerance promoting bacterium with potential use in agriculture. Since recent research showed the importance of microbial partners for enhancing the growth and health of plants, a review of the different factors influencing plant-associated microbial communities is presented and a framework for the successful application of microbial inoculants in agriculture is proposed. The presented work demonstrates a holistic approach for tackling agricultural challenges using microbial inoculants from desert plants by combining culturomics, phenomics, genomics and transcriptomics. Microbial inoculants are promising tools for studying abiotic stress tolerance mechanisms in plants, and they provide an eco-friendly solution for increasing crop yield in arid and semi-arid regions, especially in light of a dramatically growing human population and detrimental effects of global warming and climate change.

Microorganisms will play a significant role in the agricultural revolution in the coming decades and help meet the growing population's needs. Hence, understanding the impact of beneficial bacteria on crop development is key to the future of developing microbial products. The ability of PGPB to increase crop yields has been recently investigated in agriculture, as PGPB can support and protect plants under different stresses. Since PGPB interactions occur naturally, finding a method to apply beneficial bacteria while maintaining their efficiency and quality is a topic of interest. PGPB have been used as microbial inoculants, biofertilizers, and also as seed coatings. Preservation of microorganisms through desiccation has been used as the preferred method for long-term storage of microbial culture. The use of dry powders is favored over liquid cultures due to their ease of transportation and better quality control. For microbial preservation, freeze-drying has been defined as the most convenient and satisfactory preservation method for long-term storage. Freeze-drying is generally preferred over other drying techniques as it gives a high-quality dehydrated product. However, to reach a high-quality product, many parameters need to be monitored, such as bacterial cell concentration, growth medium, lyophilization buffer, rehydration, and duration of freeze-drying. In this research, SA190 was freeze-dried with 10% sucrose mixed with 5% trehalose as lyophilization buffer. Pseudomonas argentinensis SA190 was isolated from the root nodules of the desert plant Indigofera argentae in Saudi Arabia, specifically Jizan. The SA190 freeze-dried product was examined by several tests to assess the product viability and quality, such as accelerated test and water stability test. For future work, the effect of freeze-dried SA190 on plant growth and crop yield will be investigated. Moreover, optimization of the freeze-drying process, formulation, and packaging for commercial will be considered. In addition, bacterial strains isolated in DARWIN21 project with promising effects on plant growth, will be subjected to freeze-drying process.

Soils have been contaminated with cadmium (Cd) by the use of fertilizers, calcareous, pesticides and industrial and/or domestic effluents. It can be leached to groundwater, as well as be taken up by plants potentially leading to reduce growth and yield. It causes different damages to the cell, generating oxidative stress which is responsible for its toxicity, affecting all living organism. A balance in the redox state of the cell to maintain cellular integrity and metabolism is essential for organism tolerance. Thus, the antioxidant response of bacteria exposed to Cd was studied to understand the tolerance mechanism, and be able to develop a methodology to bioremediate contaminated soils. MDA and hydrogen peroxide contents and different enzymes activity of antioxidant system (SOD, CAT, GR and GST) of two strains from Burkholderia genus, one from a soil contaminated with Cd in high concentrations (strain SCMS54) and the other from soil without Cd (strain SNMS32) in two exposure time (5 and 12 h), were analyzed. Stress measurement (MDA and hydrogen peroxide content) and antioxidant enzyme activities (SOD, CAT, GR and GST) increased in almost all treatments in the presence of Cd. These results also indicate that strain SCMS54 (isolated from Cd contaminated soil) presents a higher metabolic diversity and plasticity due the expression of more isoforms of the enzymes SOD, CAT and GR. The strain also accumulates 50% more Cd. We also analyzed the response to Ni of these two strain, observing a similar response to Cd, except for GST enzyme expression, which in strain SCMS54 this enzyme was induced in the presence of Ni, indicating that this enzyme can be essential on Ni tolerance. After that, the strain isolated from Cd contaminated soil (SCMS54) was selected to proceed the studies to evaluate the benefits of tolerant microorganism-tomato plant interaction. The use of plants to remove heavy metals from contaminated soilhas less impact and a lower cost. Soil microorganisms can be able to solubilize or mobilize soil metals acting also as bioremediator. Besides the high tolerance to Cd, the strain SCMS54 can produce indole-acetic acid (IAA), solubilize inorganic phosphate and produce siderophore, revealing its potential in plantmicroorganism mutual and beneficial interaction. When interacting with tomato plants exposed to Cd, this bacterium led to decrease in plant peroxide concentration and chlorosis levels, promoted relative plant growth and reduced the root absorption of Cd resulting in an increase in plant tolerance to this highly toxic heavy metal. Indicating that inoculation of tomato plants with Burkholderia sp. SCMS54 promotes better growth when cultivated in the presence of Cd by a mechanism that appears to decrease Cd concentration in roots as a result of a bacterial-plant root beneficial interaction. / O cádmio (Cd) tem contaminado solos pelo uso de fertilizantes, calcário, agrotóxicos e resíduos industriais e/ou domésticos. Podendo ser lixiviado ao lençol freático ou absorvido pelas plantas,resultando na redução do crescimento e da produtividade. Esse metal afeta todos os organismos vivos e causa diferentes danos às células. A tolerância a esse metal se deve principalmente ao balanço do estado redox da célula para manter a integridade celular e metabolismo.Assim, foram isoladas bactérias de solo contaminado e não contaminado com Cd, selecionando isolados tolerantes a altas concentrações de diferentes metais (Cd, Ni e Zn), em seguida, foi observado a resposta do sistema antioxidante da bactéria na presença do Cd, a fim de auxiliar no desenvolvimento de metodologias para biorremediar solos contaminados. Foi quantificado MDA e peróxido de hidrogênio e a atividade de diferentes enzimas do sistema antioxidante (SOD, CAT, GR e GST) de duas estirpes do gênero Burkholderia tolerantes a todos os metais testados, uma isolada do solo contaminado com altas concentrações de Cd (estirpe SCMS54) e a outra do solo sem Cd (estirpe SNMS32) em dois tempos de exposição (5 e 12 h). Na estirpe SCMS54, as medidas de estresse (peroxidação lipídica e peróxido de hidrogênio) e a atividade das enzimas antioxidantes (SOD, CAT, GR e GST) da maioria dos tratamento com cádmio aumentaram, esta estirpe também expressa mais isoformas de SOD, CAT e GR, além de acumular 50% mais Cd. Esses resultados mostram que a estirpe SCMS54 (isolada do solo contaminado com Cd) apresenta uma maior diversidade metabólica e plasticidade. Foram analisadas também a resposta dessas duas estirpes ao Ni, observando uma resposta semelhante ao Cd, exceto na expressão da enzima GST, que no estirpe SCMS54 foi induzida na presença do Ni, indicando que essa enzima pode ser essencial na tolerância ao Ni. Portanto, a estirpe isoladado solo contaminado com Cd (SCMS54) foi selecionada para prosseguir os estudos e avaliar os benefícios da interação entre microrganismos tolerantes-plantas de tomate na fitorremediação. Essa técnica é usada remover para metais pesados do solo com um menor impacto e baixos custos. Os microrganismos do solo podem solubilizar e mobilizar metais do solo, atuando como biorremediador. Além da alta tolerância ao Cd, a estirpe SCMS54 produz ácido indol acético (AIA), solubiliza fosfato inorgânico e produz sideroforo, mostrando seu potencial na interação benéfica planta-microorganismo. Quando interagindo com as plantas de tomate expostas ao Cd, essa bactéria diminui a concentração de peróxido da planta e a clorose ocasionado pelo Cd,e reduz a absorção de Cd pela raiz resultando em um aumento da tolerância da planta ao metal pesado altamente tóxico. Assim, a inoculação de plantas de tomate com Burkholderia sp. SCMS54 promove crescimento da planta na presença de Cd, desencadeando um mecanismo que diminui a concentração de Cd nas raízes devido a essa interação benéfica bactéria-raiz da planta.

O desenvolvimento de tecnologias alternativas que visem aumentar a disponibilidade e eficiência do uso dos recursos minerais para as plantas aparecem como importante medida para se alcançar um crescimento sustentável da agricultura. Neste contexto, o suprimento de nitrogênio por meios biológicos, utilizando micro-organismos diazotróficos, dos quais os mais estudados são os rizóbios associados simbioticamente às leguminosas, é uma importante alternativa. Porém o sucesso atingido com essa simbiose em leguminosas ainda não foi alcançado em outras famílias de plantas, principalmente por limitações associadas à otimização das combinações planta-bactéria. Em gramíneas, diazotróficos endofíticos têm sido usados como inoculante, com resultados controversos. No entanto, é possível que micro-organismos diazotróficos epifíticos possam apresentar maior vantagem adaptativa devido à menor especificidade em sua relação com a planta, e serem mais eficientes em plantas não-leguminosas. O presente trabalho teve por objetivo avaliar o efeito de um inoculante produzido a partir de bactérias diazotróficas isoladas da filosfera no crescimento de milho e tomateiro. Ensaios foram realizados em condições de casa-de-vegetação, utilizando-se três diferentes isolados de bactérias diazotróficas encapsuladas em esferas de alginato sob diferentes níveis de adubação nitrogenada. A eficiência dos isolados em fixar nitrogênio foi avaliada através da atividade da nitrogenase. As populações de diazotróficos na rizosfera foram determinadas através da técnica do número mais provável (NMP) ao final do ensaio. Além disso, parâmetros como biomassa da parte aérea e das raízes foram analisados. Os dados foram submetidos à análise de variância, sendo as médias das variáveis comparadas pelo teste Duncan (p<0,05), utilizando-se o programa estatístico R. Plantas de milho, aos 60 dias após a inoculação com o isolado J8L, apresentaram matéria seca da raiz e atividade da nitrogenase 26 e 50 % superior ao controle não-inoculado, respectivamente. Plantas de tomateiro, 30 dias após a inoculação com o isolado E5L, apresentaram matéria seca da parte aérea e matéria seca da raiz 39 e 31 % superior ao controle não-inoculado, respectivamente. Parte dos efeitos observados no milho e tomateiro podem ser explicados pela atividade de fixação biológica de nitrogênio e produção de fitormônios, como auxina. A atividade da nitrogenase na rizosfera do milho, 60 dias após a inoculação foi maior no solo sem adição de N. O NMP não apresentou diferenças significativas e nos ensaios com milho e tomateiro, entre plantas inoculadas e não inoculadas, mostrando uma provável influência da comunidade diazotrófica nativa sobre a população final de diazotróficas analisada. De uma maneira geral, os isolados J8L e E5L proporcionaram ganhos significativos para as culturas do milho e tomateiro, mostrando potencial para uso como biofertilizantes. / The development of alternative technologies to increasing availability and use efficiency of mineral resources for plants is an important step for sustainable agricultural production. In this context, the supply of nitrogen by biological means, using diazotrophic microorganisms, of which the most studied are rhizobia symbiotically associated with legumes, is an important alternative. However, the efficiency of rhizobium-legume symbioses has not yet been achieved in other plant families, mainly due to limitations associated with the optimization of plant-bacterial combinations. In grasses, endophytic diazotrophs have been used as inoculant, with controversial results. However, it is possible that epiphytic diazotrophic microorganisms may have adaptive advantages over endophytes, due to the lower specificity in their associations with plants, and be more efficient in non-leguminous plants. The objective of the present work was to evaluate the effect of an inoculant produced with diazotrophic bacteria isolated from the phyllosphere on the growth of maize and tomato. Assays were carried out under greenhouse conditions using three isolates of diazotrophic bacteria encapsulated in alginate beads under different levels of nitrogen fertilization. The efficiency of the isolates in fixing nitrogen was evaluated determining nitrogenase activities. The populations of diazotrophic bacteria in the rhizosphere were determined by the most probable number (MPN) technique at the end of the experiment. In addition, parameters such as shoot and root biomass were analyzed. The data were submitted to the analysis of variance, and means were compared by the Duncan test (p<0.05), using the statistical program R. Maize plants at 60 days after inoculation with the J8L isolate presented root dry weight and nitrogenase activity in the rhizosphere 26 and 50% higher than the uninoculated control, respectively. Tomato plants, 30 days after inoculation with the E5L isolate, presented shoot and root dry weight 39 and 31% higher than the uninoculated control, respectively. Part of the effects observed in maize and tomato can be explained by the nitrogen fixation activity and auxin production. Nitrogenase activity in the maize rhizosphere, 60 days after inoculation was higher in the soil without N supply. The population of diazothrophic bacteria in the rhizosphere of inoculated and non-inoculated maize and tomato plants were not significantly different, showing a probable influence of the native diazotrophic community on the total diazotrophic population. In general, isolates J8L and E5L promoted growth of maize and tomato, showing potential for use as biofertilizers.

O desenvolvimento de tecnologias alternativas que visem aumentar a disponibilidade e eficiência do uso dos recursos minerais para as plantas aparecem como importante medida para se alcançar um crescimento sustentável da agricultura. Neste contexto, o suprimento de nitrogênio por meios biológicos, utilizando micro-organismos diazotróficos, dos quais os mais estudados são os rizóbios associados simbioticamente às leguminosas, é uma importante alternativa. Porém o sucesso atingido com essa simbiose em leguminosas ainda não foi alcançado em outras famílias de plantas, principalmente por limitações associadas à otimização das combinações planta-bactéria. Em gramíneas, diazotróficos endofíticos têm sido usados como inoculante, com resultados controversos. No entanto, é possível que micro-organismos diazotróficos epifíticos possam apresentar maior vantagem adaptativa devido à menor especificidade em sua relação com a planta, e serem mais eficientes em plantas não-leguminosas. O presente trabalho teve por objetivo avaliar o efeito de um inoculante produzido a partir de bactérias diazotróficas isoladas da filosfera no crescimento de milho e tomateiro. Ensaios foram realizados em condições de casa-de-vegetação, utilizando-se três diferentes isolados de bactérias diazotróficas encapsuladas em esferas de alginato sob diferentes níveis de adubação nitrogenada. A eficiência dos isolados em fixar nitrogênio foi avaliada através da atividade da nitrogenase. As populações de diazotróficos na rizosfera foram determinadas através da técnica do número mais provável (NMP) ao final do ensaio. Além disso, parâmetros como biomassa da parte aérea e das raízes foram analisados. Os dados foram submetidos à análise de variância, sendo as médias das variáveis comparadas pelo teste Duncan (p<0,05), utilizando-se o programa estatístico R. Plantas de milho, aos 60 dias após a inoculação com o isolado J8L, apresentaram matéria seca da raiz e atividade da nitrogenase 26 e 50 % superior ao controle não-inoculado, respectivamente. Plantas de tomateiro, 30 dias após a inoculação com o isolado E5L, apresentaram matéria seca da parte aérea e matéria seca da raiz 39 e 31 % superior ao controle não-inoculado, respectivamente. Parte dos efeitos observados no milho e tomateiro podem ser explicados pela atividade de fixação biológica de nitrogênio e produção de fitormônios, como auxina. A atividade da nitrogenase na rizosfera do milho, 60 dias após a inoculação foi maior no solo sem adição de N. O NMP não apresentou diferenças significativas e nos ensaios com milho e tomateiro, entre plantas inoculadas e não inoculadas, mostrando uma provável influência da comunidade diazotrófica nativa sobre a população final de diazotróficas analisada. De uma maneira geral, os isolados J8L e E5L proporcionaram ganhos significativos para as culturas do milho e tomateiro, mostrando potencial para uso como biofertilizantes. / The development of alternative technologies to increasing availability and use efficiency of mineral resources for plants is an important step for sustainable agricultural production. In this context, the supply of nitrogen by biological means, using diazotrophic microorganisms, of which the most studied are rhizobia symbiotically associated with legumes, is an important alternative. However, the efficiency of rhizobium-legume symbioses has not yet been achieved in other plant families, mainly due to limitations associated with the optimization of plant-bacterial combinations. In grasses, endophytic diazotrophs have been used as inoculant, with controversial results. However, it is possible that epiphytic diazotrophic microorganisms may have adaptive advantages over endophytes, due to the lower specificity in their associations with plants, and be more efficient in non-leguminous plants. The objective of the present work was to evaluate the effect of an inoculant produced with diazotrophic bacteria isolated from the phyllosphere on the growth of maize and tomato. Assays were carried out under greenhouse conditions using three isolates of diazotrophic bacteria encapsulated in alginate beads under different levels of nitrogen fertilization. The efficiency of the isolates in fixing nitrogen was evaluated determining nitrogenase activities. The populations of diazotrophic bacteria in the rhizosphere were determined by the most probable number (MPN) technique at the end of the experiment. In addition, parameters such as shoot and root biomass were analyzed. The data were submitted to the analysis of variance, and means were compared by the Duncan test (p<0.05), using the statistical program R. Maize plants at 60 days after inoculation with the J8L isolate presented root dry weight and nitrogenase activity in the rhizosphere 26 and 50% higher than the uninoculated control, respectively. Tomato plants, 30 days after inoculation with the E5L isolate, presented shoot and root dry weight 39 and 31% higher than the uninoculated control, respectively. Part of the effects observed in maize and tomato can be explained by the nitrogen fixation activity and auxin production. Nitrogenase activity in the maize rhizosphere, 60 days after inoculation was higher in the soil without N supply. The population of diazothrophic bacteria in the rhizosphere of inoculated and non-inoculated maize and tomato plants were not significantly different, showing a probable influence of the native diazotrophic community on the total diazotrophic population. In general, isolates J8L and E5L promoted growth of maize and tomato, showing potential for use as biofertilizers.

Submitted by (lucia.rodrigues@ufrpe.br) on 2017-02-21T12:25:29Z No. of bitstreams: 1 Andrea Maria Andre Gomes.pdf: 1093534 bytes, checksum: b089cef12b68df384d0aec41d274408e (MD5) / Made available in DSpace on 2017-02-21T12:25:29Z (GMT). No. of bitstreams: 1 Andrea Maria Andre Gomes.pdf: 1093534 bytes, checksum: b089cef12b68df384d0aec41d274408e (MD5) Previous issue date: 2003-03-14 / Lettuce (Lactuca sativa L.) is one of the most consumed vegetables in the world. In spite of the importance of this crop in Pernambuco Brazil, there are no studies on the use of plant growth-promoting rhizobacteria for production of organic transplants, as well as a diagrammatic scale for evaluating the severity of Cercospora leaf spot (Cercospora longissima) in epidemiological surveys. Epiphytic and endophytic bacterial strains applied through simultaneous bacterization on seedlings and plants were tested in greenhouse using cv. Verônica. In field the strains C25 (Bacillus thuringiensis subvar. kenyae) and C116 (Bacillus pumilus) were tested separately and in mixture using cvs. Verdinha and Verônica. Seedlings treated with C116 showed significant increase in relation to controls for root fresh weight, shoot fresh weight and total fresh weight as well as those treated with C25 for root fresh weight and total fresh weight. The strain C25 also significantly increased the level of foliar N. Aiming tostandardize methods to quantify the severity of Cercospora leaf spot of lettuce, a diagrammatic scale was developed with 1, 3, 6, 11, 20, 34, 51 and 68% diseased leaf areas. The diagrammatic scale was validated by 10 raters using 50 leaves with different levels of severity, previously measured by the software AutoCAD® R14 for Windows. There were performed two evaluations with a 7-day interval in which different sequences of the same leaves were visually estimated by the same raters. The accuracy and precision of each rater was determined through simple linear regression between actual and estimated severity. The scale proportioned good levels of accuracy and precision, and despite severity tended to be underestimated, the absolute errors were around 10%. Generally the raters showed good repeatability of estimative. Surveys ofCercospora leaf spot severity were performed in commercial plantations, including conventional and organic systems, in Mata and Agreste of Pernambuco, in two planting seasons. Disease prevalence in conventional systems ranged from 92 to 100% and in organic systems from 88 to 100%. In conventional plantings the severity significantly varied from 0.84 to 16.86 in January-April and 0.00 to 2.44 in June-September. In this system significant differences were observed among the counties Chã Grande (4.99) and Vitória de Santo Antão (9.14), only in January-April. Still in the conventional farming, there were no significant differences of disease severity among groups, cultivars of lettuce and number of fungicide applications within each season. In the organic system disease severity varied significantly from 0.07 to 22.53 in January-April and from 0.00 to 15.18 in June-September. In this system there were no significant differences fordisease severity averages in Bom Jardim, Chã Grande, Glória de Goitá and Gravatá, within each season. In January-April, but not in June-September, the average of Cercospora leaf spot severity significantly differed among groups and cultivars of lettuce. The group Lisa cv. Verdinha (0,68), showed significantly less severity than the groups Crespa cv. Verônica (10.61) and Americana cv. Lucy Brown (7.71). The Pearson test did not find significant correlations for severity between the studied seasons in both conventional and organic systems. The Kruskall-Wallis test did not detected significant differences for severity among the conventional and organic systems in each period. However there was significant difference for severity between the two seasons in each system. / A alface (Lactuca sativa L.) é uma das hortaliças mais consumidas no mundo. Apesar da importância desta cultura em Pernambuco, inexistem estudos sobre o uso de bactérias promotoras de crescimento de plantas para a produção de mudas orgânicas bem como de uma escala diagramática para a avaliação da severidade da cercosporiose (Cercospora longissima) em levantamentos epidemiológicos. Isolados bacterianos epifíticos e endofíticos, aplicados por bacterização simultânea nas sementes e substrato, foram testados em estufa utilizando a cultivar Verônica. Em campo, foram testados os isolados C25 (Bacillus thuringiensis subvar. kenyae) e C116 (Bacillus pumilus), separadamente e em mistura, nas cultivares Verdinha e Verônica. As mudas apresentaram aumento significativo para matéria fresca da raiz, da parte aérea e totalutilizando o isolado C116 e para matéria fresca da raiz e total utilizando-se o C25. O isolado C25 elevou significativamente o teor foliar de N. Para padronizar métodos de quantificação da severidade da cercosporiose, foi desenvolvida uma escala diagramática com os níveis 1, 3, 6, 11, 20, 34, 51 e 68% de área foliar lesionada. A escala diagramática foi validada por 10 avaliadores que utilizaram 50 folhas com sintomas da doença em diferentes níveis de severidade, mensuradas pelo programa AutoCAD® R14 for Windows. Realizou-se duas avaliações com intervalo de sete dias, onde seqüências diferentes das mesmas folhas foram estimadas visualmente pelos mesmos avaliadores. A acurácia e a precisão de cada avaliador foram determinadas por regressão linear simples, entre a severidade real e a estimada. A escala proporcionou bons níveis de acurácia e precisão e, apesar de evidenciar tendência a subestimativa, os erros absolutosconcentraram-se na faixa de 10%. Em geral, os avaliadores demonstraram boarepetibilidade nas estimativas. Foram efetuados levantamentos da severidade da doença em áreas de cultivo convencional e orgânico da Zona da Mata e Agreste de Pernambuco, em dois períodos de plantio. Foi registrada prevalência da doença em cultivo convencional variando de 92 a 100% e em orgânico, de 88 a 100%. No cultivo convencional, a severidade variou significativamente entre 0,84 a 16,86 no período janeiro-abril e 0,00 a 2,44 no período junho-setembro. Nesse cultivo, foram constatadas diferenças significativas entre os municípios Chã Grande (4,99) e Vitória de Santo Antão (9,14), apenas no período de janeiro-abril. Ainda no cultivo convencional, não foram constatadas diferenças significativas da severidade da cercosporiose entre grupos e cultivares de alface e, entre número de aplicações de fungicidas, dentro de cada período. No cultivo orgânico, verificou-se diferença significativa na severidade da doença em janeiro-abril variando de 0,07 a 22,53 e em junho-setembro variando de 0,00 a 15,18. Nesse cultivo não foram constadas diferenças significativas para médias de severidade nos plantios de Bom Jardim, Chã Grande, Glória de Goitá e Gravatá, dentro de cada período. No período janeiro-abril, mas não em junho-setembro, as médias de severidade da cercosporiose diferiram significativamente entre grupos e cultivares de alface. O grupo Lisa, cv. Verdinha (0,68), diferiu, significativamente dos grupos Crespa cv. Verônica (10,61) e Americana cv. Lucy Brown (7,71). Não foram constatadas correlações significativas para a severidade entre os períodos estudados, tanto no cultivo convencional quanto no orgânico. Pelo teste de Kruskall-Wallis, não houve diferença significativa para a severidade entre os cultivos convencional e orgânico, nos dois períodos. Por outro lado, houve diferença significativa para a severidade entre os dois períodos nos dois tipos de cultivo.

Plants often live in association with growth-promoting bacteria, which provide them with several benefits. One such benefit is the lowering of plant ethylene levels through the action of the bacterial enzyme 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase that cleaves the immediate biosynthetic precursor of ethylene, ACC. The plant hormone ethylene is responsible for many aspects of plant growth and development but under stressful conditions ethylene exacerbates stress symptoms. The ACC deaminase-containing bacterium Pseudomonas putida UW4, isolated from the rhizosphere of reeds, is a potent plant growth-promoting strain and as such was used, along with an ACC deaminase minus mutant of this strain, to study the role of ACC deaminase in plant growth-promotion. Also, transgenic plants expressing a bacterial ACC deaminase gene were used to study the role of this enzyme in plant growth and stress tolerance in the presence and absence of nickel. Transcriptional changes occurring within plant tissues were investigated with the use of an Arabidopsis oligonucleotide microarray. The results showed that transcription of genes involved in hormone regulation, secondary metabolism and the stress response changed in all treatments. In particular, the presence of ACC deaminase caused genes for auxin response factors to be up-regulated in plant tissues suggesting a de-repression of auxin signaling in the absence of high levels of ethylene. Also, transgenic plants had longer roots and grew faster than the non-transformed plants and genes involved in the stress response and secondary metabolism were up-regulated. Plants inoculated with bacteria had lower levels of secondary metabolism gene expression and slightly higher stress response gene expression than uninoculated plants. Yet, inoculation with the ACC deaminase-expressing bacterium caused less up-regulation of plant genes involved in stress and defense responses and the down-regulation of genes involved in nitrogen metabolism in comparison to plants inoculated with the ACC deaminase minus mutant. Nickel stress caused the down-regulation of genes involved in photosynthesis and carbon fixation and the up-regulation of genes involved in stress responses, and amino acid and lipid breakdown suggesting energy starvation. When transgenic plants expressing ACC deaminase in the roots were exposed to nickel stress, plant stress symptoms were significantly lower and biomass was significantly higher suggesting that lowering the level of ethylene relieved many of the stress symptoms. In fact, genes involved in photosynthesis, secondary metabolism and nitrate assimilation were up-regulated in transgenic plants compared with non-transformed plants in the presence of nickel, suggesting that ACC deaminase is effective at reducing the severe effects of this metal stress.

Plants often live in association with growth-promoting bacteria, which provide them with several benefits. One such benefit is the lowering of plant ethylene levels through the action of the bacterial enzyme 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase that cleaves the immediate biosynthetic precursor of ethylene, ACC. The plant hormone ethylene is responsible for many aspects of plant growth and development but under stressful conditions ethylene exacerbates stress symptoms. The ACC deaminase-containing bacterium Pseudomonas putida UW4, isolated from the rhizosphere of reeds, is a potent plant growth-promoting strain and as such was used, along with an ACC deaminase minus mutant of this strain, to study the role of ACC deaminase in plant growth-promotion. Also, transgenic plants expressing a bacterial ACC deaminase gene were used to study the role of this enzyme in plant growth and stress tolerance in the presence and absence of nickel. Transcriptional changes occurring within plant tissues were investigated with the use of an Arabidopsis oligonucleotide microarray. The results showed that transcription of genes involved in hormone regulation, secondary metabolism and the stress response changed in all treatments. In particular, the presence of ACC deaminase caused genes for auxin response factors to be up-regulated in plant tissues suggesting a de-repression of auxin signaling in the absence of high levels of ethylene. Also, transgenic plants had longer roots and grew faster than the non-transformed plants and genes involved in the stress response and secondary metabolism were up-regulated. Plants inoculated with bacteria had lower levels of secondary metabolism gene expression and slightly higher stress response gene expression than uninoculated plants. Yet, inoculation with the ACC deaminase-expressing bacterium caused less up-regulation of plant genes involved in stress and defense responses and the down-regulation of genes involved in nitrogen metabolism in comparison to plants inoculated with the ACC deaminase minus mutant. Nickel stress caused the down-regulation of genes involved in photosynthesis and carbon fixation and the up-regulation of genes involved in stress responses, and amino acid and lipid breakdown suggesting energy starvation. When transgenic plants expressing ACC deaminase in the roots were exposed to nickel stress, plant stress symptoms were significantly lower and biomass was significantly higher suggesting that lowering the level of ethylene relieved many of the stress symptoms. In fact, genes involved in photosynthesis, secondary metabolism and nitrate assimilation were up-regulated in transgenic plants compared with non-transformed plants in the presence of nickel, suggesting that ACC deaminase is effective at reducing the severe effects of this metal stress.