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Apios priceana is a native endangered species plant found in the Southeast United States. It is characterized as a leguminous species that bears wisteria like clusters with pea like flowers, a large tuberous root and four to six inch long seed pods. It is believed the Native Americans and early European settlers relied on this species as a source of protein and utilized the seeds for cultivation of the tuberous “potato” which formed. Apios priceana contains an average of 13% fiber, 6.9% protein, 71% carbohydrate and 9 of the 11 essential amino acids needed in human diets (Walter et al.,1986). In addition, A. priceanatuberous roots contain anti-carcinogenic properties known to be used to treat prostate and breast cancer as well as lowering blood pressure and cholesterol with an added use for diabetes. If removed from the endangered species list it could prove to be a valuable agronomic crop. Its use spans human and animal consumption, bio fuel, medicinal and horticultural purposes. This research was initiated to investigate a biological symbiosis between A. priceana and known beneficial soil bacteria which may indicate growth potential of known colonies. Experimental treatments were 1) no inoculation 2) Azospirillum brasilense inoculate 3) Bradyrhizobium japonicum inoculate and 4) Rhizobium leguminosarum biovar viceae inoculate. Specimens were evaluated at 30, 60 and 90 day’s growth from emergence for taproot length, number of lateral roots and taproot girth. Due to non-germination of seeds, data presented is for treatments 2 and 3. The correlation coefficient for average taproot length, number of lateral roots developed and taproot girth per treatment was as follows: taproot length to number of lateral roots, positive correlation coefficient 0.996; taproot length to taproot girth, positive correlation coefficient 0.999; and number of lateral roots to taproot girth, positive correlation coefficient 0.991. All correlation coefficients are significant at the 0.01 level.

Most members of the Rhizobiaceae possess single copies of the poly-3-hydroxybutyrate biosynthesis genes, phbA, phbB and phbC. Analysis of the genome sequence of Bradyrhizobium japonicum reveals the presence of five homologues of the PHB synthase gene phbC as well as two homologues of the biosynthesis operon, phbAB. The presence of multiple, seemingly redundant homologues may suggest a functional importance. Each B. japonicum phbC gene was cloned and used to complement the pleiotropic phenotype of a Sinorhizobium meliloti phbC mutant; this mutant is unable to synthesize PHB, grow on certain PHB cycle intermediates and forms non-mucoid colonies on yeast mannitol medium. Two of the five putative B. japonicum phbC genes were found to complement the S. meliloti phbC mutant phenotype on D-3-hydroxybutyrate although none of them could fully complement the phenotype on acetoacetate. Both complementing genes were also able to restore PHB accumulation and formation of mucoid colonies on yeast mannitol agar to phbC mutants. In-frame deletions were constructed in three of the five phbC open reading frames in B. japonicum, as well as in both phbAB operons, by allelic replacement. One of the phbC mutants was unable to synthesize PHB under free-living conditions; one of the two phbAB operons was shown to be necessary and sufficient for PHB production under free-living conditions. These mutants also demonstrated an exopolysaccharide phenotype that was comparable to S meliloti PHB synthesis mutants. These strains were non-mucoid when grown under PHB-inducing conditions and, in contrast to wild-type B. japonicum, formed a compact pellet upon centrifugation. Interestingly, none of the mutants exhibited carbon-utilization phenotypes similar to those exhibited by S. meliloti PHB mutants. Wild-type B. japonicum accumulates PHB during symbiosis, and plants inoculated with the phbC mutants demonstrate a reproducible reduction in shoot dry mass. Analysis of bacteroid PHB accumulation in the mutant strains suggests that the phbAB operons of B. japonicum are differently regulated relative to growth under free-living conditions; mutants of the second phbAB operon demonstrated a significant reduction in PHB accumulation during symbiosis. These data suggest that the first phbAB operon is required for PHB synthesis only under free-living conditions, but is able to partially substitute for the second operon during symbiosis. Deletion of both phbAB operons completely abolished PHB synthesis in bacteroids. Analysis of the upstream regions of these genes suggest the existence of putative RpoN binding sites, perhaps indicating a potential mode of regulation and highlighting the metabolic complexity that is characteristic of the Rhizobiaceae. PHB metabolism in S. meliloti has been studied in considerable detail with two notable exceptions. No reports of the construction of either a β-ketothiolase (phbA) or a PHB depolymerase (phaZ ) mutant have ever been documented. The phaZ gene, encoding the first enzyme of the catabolic half of the PHB cycle in S. meliloti, was identified and a phaZ mutant strain was generated by insertion mutagenesis. The phaZ mutant demonstrates a Fix+ symbiotic phenotype and, unlike other PHB cycle mutants, does not demonstrate reduced rhizosphere competitiveness. Bacteroids of this strain were shown to accumulate PHB, demonstrating for the first time that S. meliloti is able to synthesize and accumulate PHB during symbiosis. Interestingly, there is no significant difference in shoot dry mass of plants inoculated with the phaZ mutant, suggesting that PHB accumulation does not occur at the expense of nitrogen fixation. The phaZ mutant strain was also used to demonstrate roles for PhaZ in the control of PHB accumulation and exopolysaccharide production. When grown on high-carbon media, this mutant demonstrates a mucoid phenotype characteristic of exopolysaccharide production. Subsequent analyses of a phoA::exoF fusion confirmed elevated transcription levels in the phaZ mutant background. In contrast, mutants of the PHB biosynthesis gene, phbC, have a characteristically dry phenotype and demonstrate reduced exoF transcriptional activity. The phaZ mutant also demonstrates a significant increase in PHB accumulation relative to the wild-type strain. Previous work on phasin mutants in S. meliloti demonstrated that they lack the ability to synthesize PHB. Transduction of the phaZ lesion into the phasin mutant background was used to construct a phaZ-phasin mutant strain. Analysis of the PHB biosynthesis capacity of this strain showed that the lack of PHB synthesis exhibited by S. meliloti phasin mutants is due to loss of PHB biosynthesis activity and not due to an inherent instability in the PHB granules themselves. A recent study suggested that some bacteria may possess an alternate pathway for acetate assimilation that would bypass the need for the glyoxylate cycle in organisms that do not possess the enzyme, isocitrate lyase. In these organisms, acetate is assimilated through the ethylmalonyl-CoA pathway, which has significant overlap with the anabolic half of the PHB cycle, including reliance on the PHB intermediate 3-hydroxybutyryl-CoA. The observation that phbB and phbC mutants of S. meliloti are unable to grow well on acetoacetate -- coupled with previously unexplained data that show a class of mutants (designated bhbA-D) are able to grow on acetate, but not on hydroxybutyrate or acetoacetate -- made it tempting to speculate that an ethylmalonyl-CoA-like pathway might be present in S. meliloti, and that this pathway might overlap with the PHB cycle at the point of 3-hydroxybutyryl-CoA. An in-frame mutation of phbA was constructed by cross-over PCR and allelic replacement. This mutant exhibited a complete abolition of growth on acetoacetate, suggesting that PhbA represents the only exit point for carbon from the PHB cycle and that an alternative ethylmalonyl-CoA-like pathway is not present in this organism. During symbiosis, rhizobial cells are dependent on the provision of carbon from the host plant in order to fuel cellular metabolism. This carbon is transported into the bacteroids via the dicarboxylate transport protein, DctA. Most rhizobia possess single copies of the transporter gene dctA and its corresponding two-component regulatory system dctBD. The completed genome sequence of B. japonicum suggests that it possesses seven copies of dctA. Complementation of Sinorhizobium meliloti dct mutants using the cosmid bank of B. japonicum USDA110 led to the identification a dctA locus and a dctBD operon. Interestingly, the B. japonicum dctABD system carried on the complementing cosmid was not able to complement the symbiotic deficiency of S. meliloti strains carrying individual mutations in either dctA, dctB, or dctD suggesting that the B. japonicum dctBD is unable to recognize either DctB/DctD or the DctB/DctD-independent regulatory elements in S. meliloti. All seven B. japonicum dctA ORFs were cloned and an analysis of their capacity to complement the free-living phenotype of a S. meliloti dctA mutant demonstrated that they all possess some capacity for dicarboxylate transport. Mutants of all seven B. japonicum dctA ORFs were constructed and an analysis of their free-living phenotypes suggested that significant functional redundancy exists in B. japonicum DctA function. Given the large number of potential dctA genes in the genome, coupled with an apparent lack of dctBD regulators, it is tempting to speculate that different DctA isoforms may be used during free-living and symbiotic growth and may be subject to different regulatory mechanisms than those of better-studied systems. A comprehensive analysis of desiccation tolerance and ion sensitivity in S. meliloti was conducted. The results of these analyses suggest that genetic elements on both pSymA and pSymB may play a significant role in enhancing cell survival under conditions of osmotic stress. The S. meliloti expR+ strains SmUW3 and SmUW6 were both shown to exhibit considerably higher desiccation tolerance than Rm1021, suggesting a role for enhanced exopolysaccharide production in facilitating survival under adverse conditions. Furthermore, scanning electron microscopy of inoculated seeds suggests that S. meliloti cells initiate biofilm formation upon application to the surface of seeds. This finding has implications for the analysis of OSS and the development of desiccation assays and may explain some of the variability that is characteristic of desiccation studies.

Most members of the Rhizobiaceae possess single copies of the poly-3-hydroxybutyrate biosynthesis genes, phbA, phbB and phbC. Analysis of the genome sequence of Bradyrhizobium japonicum reveals the presence of five homologues of the PHB synthase gene phbC as well as two homologues of the biosynthesis operon, phbAB. The presence of multiple, seemingly redundant homologues may suggest a functional importance. Each B. japonicum phbC gene was cloned and used to complement the pleiotropic phenotype of a Sinorhizobium meliloti phbC mutant; this mutant is unable to synthesize PHB, grow on certain PHB cycle intermediates and forms non-mucoid colonies on yeast mannitol medium. Two of the five putative B. japonicum phbC genes were found to complement the S. meliloti phbC mutant phenotype on D-3-hydroxybutyrate although none of them could fully complement the phenotype on acetoacetate. Both complementing genes were also able to restore PHB accumulation and formation of mucoid colonies on yeast mannitol agar to phbC mutants. In-frame deletions were constructed in three of the five phbC open reading frames in B. japonicum, as well as in both phbAB operons, by allelic replacement. One of the phbC mutants was unable to synthesize PHB under free-living conditions; one of the two phbAB operons was shown to be necessary and sufficient for PHB production under free-living conditions. These mutants also demonstrated an exopolysaccharide phenotype that was comparable to S meliloti PHB synthesis mutants. These strains were non-mucoid when grown under PHB-inducing conditions and, in contrast to wild-type B. japonicum, formed a compact pellet upon centrifugation. Interestingly, none of the mutants exhibited carbon-utilization phenotypes similar to those exhibited by S. meliloti PHB mutants. Wild-type B. japonicum accumulates PHB during symbiosis, and plants inoculated with the phbC mutants demonstrate a reproducible reduction in shoot dry mass. Analysis of bacteroid PHB accumulation in the mutant strains suggests that the phbAB operons of B. japonicum are differently regulated relative to growth under free-living conditions; mutants of the second phbAB operon demonstrated a significant reduction in PHB accumulation during symbiosis. These data suggest that the first phbAB operon is required for PHB synthesis only under free-living conditions, but is able to partially substitute for the second operon during symbiosis. Deletion of both phbAB operons completely abolished PHB synthesis in bacteroids. Analysis of the upstream regions of these genes suggest the existence of putative RpoN binding sites, perhaps indicating a potential mode of regulation and highlighting the metabolic complexity that is characteristic of the Rhizobiaceae. PHB metabolism in S. meliloti has been studied in considerable detail with two notable exceptions. No reports of the construction of either a β-ketothiolase (phbA) or a PHB depolymerase (phaZ ) mutant have ever been documented. The phaZ gene, encoding the first enzyme of the catabolic half of the PHB cycle in S. meliloti, was identified and a phaZ mutant strain was generated by insertion mutagenesis. The phaZ mutant demonstrates a Fix+ symbiotic phenotype and, unlike other PHB cycle mutants, does not demonstrate reduced rhizosphere competitiveness. Bacteroids of this strain were shown to accumulate PHB, demonstrating for the first time that S. meliloti is able to synthesize and accumulate PHB during symbiosis. Interestingly, there is no significant difference in shoot dry mass of plants inoculated with the phaZ mutant, suggesting that PHB accumulation does not occur at the expense of nitrogen fixation. The phaZ mutant strain was also used to demonstrate roles for PhaZ in the control of PHB accumulation and exopolysaccharide production. When grown on high-carbon media, this mutant demonstrates a mucoid phenotype characteristic of exopolysaccharide production. Subsequent analyses of a phoA::exoF fusion confirmed elevated transcription levels in the phaZ mutant background. In contrast, mutants of the PHB biosynthesis gene, phbC, have a characteristically dry phenotype and demonstrate reduced exoF transcriptional activity. The phaZ mutant also demonstrates a significant increase in PHB accumulation relative to the wild-type strain. Previous work on phasin mutants in S. meliloti demonstrated that they lack the ability to synthesize PHB. Transduction of the phaZ lesion into the phasin mutant background was used to construct a phaZ-phasin mutant strain. Analysis of the PHB biosynthesis capacity of this strain showed that the lack of PHB synthesis exhibited by S. meliloti phasin mutants is due to loss of PHB biosynthesis activity and not due to an inherent instability in the PHB granules themselves. A recent study suggested that some bacteria may possess an alternate pathway for acetate assimilation that would bypass the need for the glyoxylate cycle in organisms that do not possess the enzyme, isocitrate lyase. In these organisms, acetate is assimilated through the ethylmalonyl-CoA pathway, which has significant overlap with the anabolic half of the PHB cycle, including reliance on the PHB intermediate 3-hydroxybutyryl-CoA. The observation that phbB and phbC mutants of S. meliloti are unable to grow well on acetoacetate -- coupled with previously unexplained data that show a class of mutants (designated bhbA-D) are able to grow on acetate, but not on hydroxybutyrate or acetoacetate -- made it tempting to speculate that an ethylmalonyl-CoA-like pathway might be present in S. meliloti, and that this pathway might overlap with the PHB cycle at the point of 3-hydroxybutyryl-CoA. An in-frame mutation of phbA was constructed by cross-over PCR and allelic replacement. This mutant exhibited a complete abolition of growth on acetoacetate, suggesting that PhbA represents the only exit point for carbon from the PHB cycle and that an alternative ethylmalonyl-CoA-like pathway is not present in this organism. During symbiosis, rhizobial cells are dependent on the provision of carbon from the host plant in order to fuel cellular metabolism. This carbon is transported into the bacteroids via the dicarboxylate transport protein, DctA. Most rhizobia possess single copies of the transporter gene dctA and its corresponding two-component regulatory system dctBD. The completed genome sequence of B. japonicum suggests that it possesses seven copies of dctA. Complementation of Sinorhizobium meliloti dct mutants using the cosmid bank of B. japonicum USDA110 led to the identification a dctA locus and a dctBD operon. Interestingly, the B. japonicum dctABD system carried on the complementing cosmid was not able to complement the symbiotic deficiency of S. meliloti strains carrying individual mutations in either dctA, dctB, or dctD suggesting that the B. japonicum dctBD is unable to recognize either DctB/DctD or the DctB/DctD-independent regulatory elements in S. meliloti. All seven B. japonicum dctA ORFs were cloned and an analysis of their capacity to complement the free-living phenotype of a S. meliloti dctA mutant demonstrated that they all possess some capacity for dicarboxylate transport. Mutants of all seven B. japonicum dctA ORFs were constructed and an analysis of their free-living phenotypes suggested that significant functional redundancy exists in B. japonicum DctA function. Given the large number of potential dctA genes in the genome, coupled with an apparent lack of dctBD regulators, it is tempting to speculate that different DctA isoforms may be used during free-living and symbiotic growth and may be subject to different regulatory mechanisms than those of better-studied systems. A comprehensive analysis of desiccation tolerance and ion sensitivity in S. meliloti was conducted. The results of these analyses suggest that genetic elements on both pSymA and pSymB may play a significant role in enhancing cell survival under conditions of osmotic stress. The S. meliloti expR+ strains SmUW3 and SmUW6 were both shown to exhibit considerably higher desiccation tolerance than Rm1021, suggesting a role for enhanced exopolysaccharide production in facilitating survival under adverse conditions. Furthermore, scanning electron microscopy of inoculated seeds suggests that S. meliloti cells initiate biofilm formation upon application to the surface of seeds. This finding has implications for the analysis of OSS and the development of desiccation assays and may explain some of the variability that is characteristic of desiccation studies.

Submitted by MARCOS LEANDRO TEIXEIRA DE OLIVEIRA (marcosteixeira@ufv.br) on 2018-09-18T13:33:07Z No. of bitstreams: 1 texto completo.pdf: 2023955 bytes, checksum: c00bada9d7cdc721128642c40a1fc2a1 (MD5) / Made available in DSpace on 2018-09-18T13:33:07Z (GMT). No. of bitstreams: 1 texto completo.pdf: 2023955 bytes, checksum: c00bada9d7cdc721128642c40a1fc2a1 (MD5) Previous issue date: 2017-03-31 / Na natureza, um fitopatógeno geralmente está sob influência de um complexo de microrganismos, que associados garantem o equilibrio ecológico estável. Com foco no fungo nematófago Pochonia chlamydosporia, começamos investigando sua compatibilidade com Bradyrhizobium japonicum em soja e a influência dessa interação sobre o controle do nematoide das galhas e sobre a absorção de nutrientes pela planta. Constatou-se que a aplicação conjunta desses dois organismos não prejudica a ação de controle de nematoides por P. chlamydosporia e nem a fixação de N 2 por B. japonicum. Adicionalmente, quando os dois agentes estavam juntos, ocorreu maior produção de nódulos da bactéria nas raízes e aumento do conteúdo de Fe na parte aérea das plantas de soja. No segundo capítulo, a compatibilidade dos agentes de controle biológico de nematoides, P. chlamydosporia e P. penetrans foi avaliada. A co-aplicação dos microrganismos possibilitou maior redução do número de ovos do nematoide do que a aplicação em separado e foi possível observar a associação do fungo nas raízes infectadas por nematoides colonizados por P. penetrans. Pesquisamos ainda, no terceiro capítulo, a presença de vírus em isolados de P. chlamydosporia. Dos dezoito isolados avaliados, apenas um (Pc-M4) estava infectado por dois virus, um com genoma de RNA fita dupla (dsRNA) e outro de RNA fita simples sentido negativo (-ssRNA). Os nomes propostos para os micovírus são Pochonia chlamydosporia chrysovirus 1 (PcCV1) e Pochonia chlamydosporia negative-stranded RNA virus 1 (PcNSRV1). Ensaios biológicos do isolado fúngico Pc-M4 revelaram que este foi capaz de parasitar ovos, produzir metabólitos e proteases letais aos juvenis e reduzir a reprodução do nematoide de galhas M. javanica. Os resultados apresentados indicam que o fungo P. chlamydosporia é capaz de interagir com diferentes organismos sem perder a capacidade de controlar o nematoide de galhas e de promover o crescimento vegetal, o que faz dele um excelente agente de biocontrole de nematoides. / In nature, a plant pathogen is usually under the influence of a complex of microorganisms, which guarantees stable ecological balance. Focusing on the nematophagous fungus Pochonia chlamydosporia, we started investigating its compatibility with Bradyrhizobium japonicum in soybean. We also looked at the influence of this interaction on the control of the root knot nematode and on the nutrient uptake by the plant. It was found that the joint application of these two organisms does not affect the action of control of nematodes by P. chlamydosporia nor the fixation of N 2 by B. japonicum. In addition, when the two agents were together, there was a higher production of nodules of the bacteria in the roots and an increase in the Fe content in the aerial part of the soybean plants. In the second chapter, the compatibility of biological control agents of nematodes, P. chlamydosporia and P. penetrans was evaluated. The co-application of the microorganisms allowed a greater reduction in the number of nematode eggs than the separate application. It was possible to observe the association of the fungus in the roots infected by nematodes colonized by P. penetrans. We also investigated the presence of viruses in isolates of P. chlamydosporia in the third chapter. Of the eighteen isolates evaluated, only one (Pc-M4) was infected by two viruses, one with double-stranded RNA genome (dsRNA) and the other with RNA single-stranded sense negative (-ssRNA). The proposed names for the mycoviruses are Pochonia chlamydosporia chrysovirus 1 (PcCV1) and Pochonia chlamydosporia negative-stranded RNA virus 1 (PcNSRV1). Biological assays of the fungal isolate Pc-M4 revealed that it was able to parasitize eggs, produce metabolites, lethal proteases to juveniles and reduce reproduction of M. javanica. The results indicated that the fungus P. chlamydosporia is capable of interacting with different organisms without losing the ability to control the root knot nematode and to promote plant growth. This makes it an excellent biocontrol agent for plant parasitic nematodes.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第21152号 / 農博第2278号 / 新制||農||1059(附属図書館) / 学位論文||H30||N5126(農学部図書室) / 京都大学大学院農学研究科農学専攻 / (主査)教授 奥本 裕, 教授 白岩 立彦, 教授 冨永 達 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

Maximizing productivity and profitability are the primary reasons for double-cropping soybean with small grain in the Mid-Atlantic, USA. Reduced double-crop yield can be attributed to: delayed planting that results in a shortened growing season and less vegetative growth; later-maturing cultivars that terminate main stem growth after flowering and have less growth and nodes; less soil moisture and plant-available nutrients due to small grain uptake; greater air and soil temperatures during vegetative stages that reduce early-season growth; and more favorable conditions for disease development during pod and seed formation. Field experiments were conducted in 2012 and 2013 in eastern Virginia to 1) evaluate cultivar stem growth habit, seeding rate, seed-applied inoculant, starter nitrogen (N) applied at planting, and foliar fungicide on soybean vegetative growth, total N uptake (TNU), seed yield and quality, and yield components; 2) determine the effect of starter N rate, applied with and without inoculant, on soybean vegetative growth, TNU, seed yield and quality, and yield components; and 3) evaluate the response of maturity group (MG) IV and V soybean cultivars to foliar fungicide. Greater seeding rates, inoculant, N, and fungicide typically were not required together to increase yield. Although cultivar interacted with other factors, early-maturing indeterminate 95Y01 yielded more than late-maturing determinate 95Y20 at 4 of 6 locations. Seeding rate interacted with other factors, but the greater seeding rate increased MG IV yield at 1 of 6 locations and decreased MG V yield at 2 of 6 locations. Starter N increased seed yield by 6 kg ha-1 per kg N applied until yield plateaued at 16 kg N ha-1, which continued to 31 kg N ha-1. When N rate was increased greater than 31 kg N ha-1, yield decreased. Fungicide increased yield for MG IV and V cultivars at 4 of 6 and 3 of 6 locations, respectively and prevented yield loss via mid- to late-season disease control, delayed leaf drop, and greater seed size. Optimum fungicide timing depended on environment and disease development. These data assisted in understanding agronomic inputs' combined or individual effects on double-crop soybean growth, canopy, N uptake, seed yield, and yield components. / Ph. D.

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No. of bitstreams: 1 Dissertação Final Ewerton Gewehr.pdf: 999222 bytes, checksum: f1b7c9952c0b914fad5652702ae2a3c3 (MD5) Previous issue date: 2015-03-02 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / O objetivo do trabalho foi analisar o efeito da aplicação do molibdênio associado ao inoculante via tratamento de sementes em soja e sua função nos caracteres agronômicos, qualidade fisiológica e atividade da enzima nitrato redutase. O experimento foi em delineamento de blocos casualizados em um modelo bifatorial com quatro repetições, onde o primeiro fator de tratamento foram as doses de molibdênio (Mo) utilizando como fonte molibdato de Sódio (solução 127g.L-1). As doses que constituíram os tratamentos foram: zero; 16; 32; 48; 64 g.100kg-1 de sementes combinadas com o segundo fator de tratamento que foi a presença e a ausência de inoculante, via tratamento de sementes em soja, no período de safra 2013/2014. No primeiro trabalho o experimento foi conduzido até a fase de maturação de campo, sendo posteriormente realizado a avalição dos caracteres agronômicos e a qualidade fisiológica das sementes produzidas. No segundo trabalho, durante a condução do experimento, foram realizadas coletas de folhas em diferentes estádios fenológicos para avaliação da atividade de enzima nitrato redutase. Os resultados das analise da atividade da nitrato redutase foi correlacionada com os dados de caracteres agronômicos e de qualidade fisiológica de sementes obtidos no primeiro capitulo. No primeiro trabalho, verificou-se, que a adição de inoculante proporciona uma melhora na qualidade fisiológica de sementes, em relação ao vigor das sementes produzidas, evidenciado uma maior porcentagem no teste de envelhecimento acelerado, além de proporcionar um aumento no comprimento e massa seca de parte aérea e de raiz. Também influenciou positivamente na altura de planta, numero de legumes por planta, numero de sementes por planta e peso de mil sementes. As sementes produzidas mediante a aplicação de molibdênio na semeadura, também promoveu benefícios no vigor das sementes, contribuindo para um crescimento linear do comprimento e massa seca de parte aérea e raiz, conforme o aumento da dose. Além disso, o aumento da dose de molibdênio afetou de forma benéfica os caracteres agronômicos, comprovando um maior peso de mil semente ao final do ciclo da cultura, e uma maior altura de planta. No segundo trabalho, verificou-se que o molibdênio com a presença de inoculante influencia positivamente na atividade da enzima nitrato redutase, tanto no estádio vegetativo como no reprodutivo. As doses de molibdênio sem a presença do inoculante proporcionam um aumento crescente da atividade da enzima nitrato redutase ate a maior dose (64 g Mo. 100 kg-1 de semente). A atividade da enzima nitrato redutase apresenta uma correlação positiva com os testes de vigor e com os caracteres agronômicos. / The objectives of this work were to analyze and compare the effects of molybdenum associated with inoculant as seed treatment in soybeans and its role in agronomic performance, physiological quality and nitrate reductase enzymeactivity . The experiment was arranged with in a randomized complete block design with four replications. The treatments were set up in a factorial design, where the first treatment factor were the doses of molybdenum (Mo) from source of sodium molybdate (127g.L-1 solution). The following doses were used: zero; 16; 32; 48; 64 g.100kg-1 and these doses were combined with the second seed treatment factor. Therefore, the second factor was the presence and absence of inoculant via soybean seed treatment in the crop season 2013/2014. In the first study, the experiment was conducted until crop maturation phase, and subsequently were performed evaluation of agronomic performance and physiological seed quality. In the second study, during the experiment, leaf samples were taken at different growth stages to evaluate the nitrate reductase enzyme activity. The results of nitrate reductase activity were correlated with the data of agronomic performance and physiological quality of seeds obtained in the first chapter. In the first study, it was found that the addition of inoculant provides an improvement in the physiological quality of seed vigor compared to seeds produced, increase percentage of germinated seeds in the accelerated aging test as well as providing an increase in the length and mass of shoot and root. Also had a positive effect on plant height, number of pods per plant, seed number per plant and thousand seed weight. The seeds produced by molybdenum application at sowing also promoted benefits in seed vigor, contributing to a linear increase in length and dry weight of shoot and root, with increasing dose. Furthermore, increasing doses of molybdenum provide beneficial effects on agronomic characters, showing a higher thousand seed weight at the end of the cycle, and a larger plant height. In the second study, it was found that molybdenum in the presence of inoculant show positive influence on the nitrate reductase enzyme activity in the vegetative and reproductive stages. The molybdenum doses without the presence of inoculant provide a growing increase in nitrate reductase activity up to the highest dose (64 g Mo. 100 kg-1 seed). The nitrate reductase activity show a positive correlation with vigor tests and agronomic characters.