Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2017-07-07T13:07:27Z No. of bitstreams: 1 2010 - Fernanda Delgado Almeida.pdf: 626850 bytes, checksum: 3a7edfb868e6c7a04004c0ce79c36a91 (MD5) / Made available in DSpace on 2017-07-07T13:07:27Z (GMT). No. of bitstreams: 1 2010 - Fernanda Delgado Almeida.pdf: 626850 bytes, checksum: 3a7edfb868e6c7a04004c0ce79c36a91 (MD5) Previous issue date: 2010-02-11 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Seeds with high molybdenum (Mo) concentration can provide amounts of the nutrient highly enough to guarantee an adequate plant growth. An essay and two experiments were carried out in pots to evaluate the effect of Mo concentration in seeds of common bean (Phaseolus vulgaris L.) on the assimilation of N from the soil and the biological N2 fixation (BNF), through measuring the activities of the nitrogenase and nitrate reductase enzymes and the contribution of the BNF by the 15N isotope dilution, at different plant growth stages. The substrate was A horizon of Argisol (Hapludult) in 10 kg pots. Seeds of the cultivar Carioca enriched or not with Mo were tested. The essay had a 2x3 factorial design: two seed Mo concentrations (low and high) and three N sources (without N, inoculated and mineral N), with two replicates. Plants were harvested at 42 days after emergence (DAE). High concentration of Mo in seeds increased shoot dry mass, the nitrate reductase activity and shoot N accumulation, but reduced nodule number. The experiment 1 had a 2x2x4 factorial design: two seed Mo concentrations (low and high), two N sources (inoculated and mineral N) and four dates of harvest (20, 34, 45 and 55 DAE), with five replicates. An extra treatment was included, with seeds with high Mo concentration, inoculation and Mo added to the soil, with four harvests. No effect of Mo added to the soil was identified, as compared to the high seed Mo. High seed Mo increased the leaf area and shoot dry mass at the four times of harvest, and the pod mass at 55 DAE, at both N sources. Seeds with high Mo concentration increased the nitrate reductase activity at 45 DAE under mineral N, and nitrogenase activity at 20 and 45 DAE under inoculation. High Mo seeds increased shoot N accumulation at both N sources at pod filling stage. The experiment 2 had a 2x2x2 factorial design: two seed Mo concentrations (low and high), two N sources (inoculated and mineral N) and two dates of harvest (38 and 51 DAE), with five replicates. The soil was previously fertilized with 15N-enriched urea. Non-nodulating bean, sunflower and sorghum were used as control plants. At 51 DAE, plants originating from high Mo seeds had higher shoot mass at both N sources, but lower nodule number under mineral N. High Mo seed increased nitrate reductase activity at 51 DAE at both N sources, and nitrogenase activity at 38 DAE in inoculated plants. High Mo seeds increased shoot N accumulation at both N sources. High Mo seeds improved the contribution of the BNF at the pod filling stage, as estimated by the 15N isotope dilution technique. It is concluded that common bean seeds enriched with Mo stimulate the assimilation of N from the soil and the BNF, increasing the accumulation of biomass / Sementes com elevadas concentra??es de molibd?nio (Mo) podem fornecer quantidades do nutriente suficientes para garantir adequado crescimento ?s plantas. Foram conduzidos um ensaio e dois experimentos com objetivo de avaliar o efeito do teor de Mo em sementes de feijoeiro (Phaseolus vulgaris L.) na assimila??o do N do solo e na fixa??o biol?gica do N2 (FBN), atrav?s da mensura??o das atividades das enzimas nitrogenase e nitrato redutase, e da contribui??o da FBN pela dilui??o isot?pica de 15N, em diferentes est?dios de desenvolvimento vegetal. O substrato foi horizonte A de Argissolo em vasos de 10 kg, utilizando-se sementes da cultivar Carioca enriquecidas ou n?o com Mo. O ensaio teve arranjo fatorial 2x3: dois teores de Mo na semente (baixo e alto) e tr?s fontes de N (sem N, inoculado e N mineral), com duas repeti??es e coleta aos 42 dias ap?s emerg?ncia (DAE). O alto Mo da semente aumentou a atividade da nitrato redutase, a massa e a acumula??o de N na parte a?rea, mas reduziu o n?mero de n?dulos. O experimento 1 teve arranjo fatorial 2x2x4: dois teores de Mo na semente (baixo e alto), duas fontes de N (inoculado e N mineral) e quatro ?pocas de coleta (20, 34, 45 e 55 DAE), com cinco repeti??es. Foi inclu?do um tratamento extra, com sementes com alto Mo, inocula??o e adi??o de Mo ao solo. N?o foi identificado efeito do Mo adicionado ao solo quando comparado com o alto Mo na semente. O alto Mo na semente aumentou a ?rea foliar e a massa de parte a?rea nas quatro ?pocas de coleta, e a massa de vagem aos 55 DAE, nas duas fontes de N. Sementes com alto Mo aumentaram a atividade da nitrato redutase aos 45 DAE sob N mineral, e a atividade da nitrogenase aos 20 e 45 DAE sob inocula??o. Sementes com alto Mo aumentaram a acumula??o de N na parte a?rea nas duas fontes de N no est?dio de enchimento das vagens. O experimento 2 teve arranjo fatorial 2x2x2: dois teores de Mo na semente (alto e baixo), duas fontes de N (inoculado e N mineral) e duas coletas (38 e 51 DAE), com cinco repeti??es. O solo foi previamente adubado com ur?ia enriquecida com 15N. O feij?o n?o nodulante, girassol e sorgo serviram como plantas controle. Aos 51 DAE, plantas oriundas de sementes com alto Mo tiveram maior massa de parte a?rea nas duas fontes de N, mas menor n?mero de n?dulos sob N mineral. O alto Mo nas sementes aumentou a atividade da nitrato redutase aos 51 DAE, nas duas fontes de N, e a atividade da nitrogenase aos 38 DAE nas plantas inoculadas. Sementes com alto Mo aumentaram a acumula??o de N na parte a?rea nas duas fontes de N. Sementes com alto Mo aumentaram a contribui??o da FBN no est?dio de forma??o das vagens. Conclui-se que sementes de feijoeiro enriquecidas com Mo estimulam tanto a assimila??o do N do solo quanto a FBN, aumentando a acumula??o de biomassa e de N do feijoeiro.

Thesis (M.Sc. (Agronomy)) -- University of Limpopo, 2021 / Soybean (Glycine max L.) is one of the valuable leguminous crops with grain used for human consumption, livestock feeding, bio-fuel (bio-diesel) production, vegetable oil and is a protein resource. The crop also fixes atmospheric nitrogen. The study aimed to evaluate the performance of two soybean varieties to a combination of inoculation and seaweed extract. The research trial was conducted at Syferkuil farm during 2017/2018 summer season in which two soybean varieties (TGx 1937-1F promiscuous) and (PAN 1583R specific-nodulating) were evaluated for their growth, nodulation and yield responses to rhizobium inoculation and seaweed extract (0 % rate (0ml/12L), 50 % rate (30ml/12L) and 100 % (60ml/12L). The research trial was laid out as a split-split plot arrangement fitted in RCBD with four replications. Inoculation significantly influenced grain yield at P≤0.05, seed nutrient content and total above-ground biomass, except for seed potassium. No inoculation significantly achieved higher primary branches per plant at P≤0.05, pod number per plant, stem diameter (P≤0.05), grain yield (P≤0.05), harvest index and total above-ground biomass at P≤0.001. The variety TGx 1937-1F had significantly (P≤0.001) higher nodule number per plant, effective nodules per plant, nodule dry weight, dried shoot biomass, leaf number per plant, pod number per plant, primary branches per plant, stem diameter, plant height, leaf chlorophyll content, total above-ground biomass, grain yield and seed iron (Fe) content. Application of full rate seaweed extract significantly (P≤0.001) increased primary branches per plant, stem diameter, leaf number per plant, plant height, shelling percentage, total above-ground biomass, grain yield, and seed content of calcium (Ca), potassium, magnesium (Mg), manganese (Mn) and sodium (Na) all at P≤0.05. Seaweed extract rate at 0 % obtained the highest harvest index (P≤0.001). Inoculation and variety TGx 1937-1F interaction exhibited a significant increase on leaf number per plant at P≤0.001, primary branches per plant at P≤0.001 and plant height at P≤0.001. Variety TGx 1937-1F, without inoculation, obtained significantly higher pod number per plant (P≤0.001), stem diameter at P≤0.001, grain yield at P≤0.05 and total above-ground biomass at P≤0.001. Variety PAN 1583R, without inoculation, obtained significantly higher harvest index and shelling percentage at P≤0.001. Interaction of vi inoculation and seaweed extract showed that no inoculation × 100 % rate of seaweed extract significantly (P≤0.001) increased primary branches per plant, leaf number per plant, stem diameter, pod number per plant and plant height. Interaction of inoculation × 100 % rate of seaweed extract increased grain yield (P≤0.001) and total above-ground biomass at P≤0.001. Inoculation × 50 % rate of seaweed extract interaction increased shelling percentage at P≤0.001. No inoculation × 0 % rate of seaweed extract interaction obtained significantly higher harvest index (P≤0.001). Interaction of variety and seaweed extract showed that variety TGx 1937-1F × 100 % rate of seaweed extract significantly increased primary branches per plant (P≤0.001), pod number per plant at P≤0.001, grain yield at P≤0.001 and total above-ground biomass at P≤0.001. The variety TGx 1937-1F × 50 % rate of seaweed extract significantly raised the size of stem diameter (P≤0.01) and plant height (P≤0.001). Three-way interactive effects of inoculation × variety TGx 1937-1F × 100 % rate of seaweed extract obtained significantly higher number of shelling percentage at P≤0.001, leaf number per plant at P≤0.05 and primary branches per plant at P≤0.001. Interaction of no inoculation × variety TGx 1937-1F × 100 % rate of seaweed extract obtained significantly high pod number per plant at P≤0.001, grain yield at P≤0.05, total above-ground biomass at P≤0.001 and plant height at P≤0.001. No inoculation × PAN 1583R × 100 % rate of seaweed extract interaction had a higher harvest index at P≤0.001. The study showed that inoculation, seaweed extract, or their combination generally enhanced seed nutrient content, especially in variety TGx 1937-1F. The study further showed that promiscuous soybean (TGx 1937-1F) had higher grain yield, under stressful growing conditions as compared to PAN 1583R variety. This implies that soybean variety TGx 1937-1F, with 50 % or 100 % application rate of seaweed extract could be recommended to smallholder farmers. Key words: Soybean, inoculation, seaweed extract, phenological development, growth, nodulation, grain yield and seed nutrient content. / National Research Foundation (NRF)

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Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2017-05-05T12:14:40Z No. of bitstreams: 1 2010 - Ricardo Ant?nio Tavares de Macedo.pdf: 1168736 bytes, checksum: f5cc6d2a34b5331058f2910d1fe16678 (MD5) / Made available in DSpace on 2017-05-05T12:14:40Z (GMT). No. of bitstreams: 1 2010 - Ricardo Ant?nio Tavares de Macedo.pdf: 1168736 bytes, checksum: f5cc6d2a34b5331058f2910d1fe16678 (MD5) Previous issue date: 2010-10-29 / Bean plants can get nitrogen from soil organic matter, fertilizer or biological fixation of atmospheric N2 (BNF). However, the biological process in this culture has shown low efficiency under field conditions. As a result, many farmers do not inoculate the seeds with efficient strains of rhizobia, being fertilizer the main source of N to this culture. Besides the absence of inoculation, high doses of N applied to the soil inhibit nodulation and BNF. However, the reasons for this inhibition are not fully understood, especially because the N is uptaked as nitrate (NO3 -) and ammonium (NH4 +). Whereas the rhizosphere of plants grown with nitrate is alkalized and ammonium is acidified, the aim of this study was evaluate the effect of pH changes in rhizosphere (pHR), caused by the metabolism of these N sources, in start of nodules formation. The experiments were conducted in growth chamber with average brightness of 400 lux, photoperiod of 12/12 hours (light/dark) and temperature 25?C ? 2?C. Plants were grown in pots with sand, soils with low (8%) and medium (25%) clay content and nutrient solution. In the 1st test (salinity) was found that ammonium had the greatest increase in electrical conductivity of the sand (EC), obtained with a 60 KgN ha-1 the value of 1.655 mS cm-1 with ammonium and 1.301 mS cm-1 with nitrate. In the following assay were compared two contrasting cultivars in capacity of nodulate, which confirmed the high (Ouro Negro) and low (Rio Tibagi) capability. As among cultivars were not significant differences in the values of pHR, in others experiments was evaluated Ouro Negro only. In this assay and in others ammonium was the source of N with more capacity of rhizosphere acidify and inhibit nodulation. Through regression analysis for each N source, was given the dose of total inhibition of nodulation (critical level), pHR at this dose and the dose which was 80% of maximum nodulation (dose of coexistence). In general, was verified the lowest doses of critical level and coexistence using ammonium than with nitrate. In the sand test (Ouro Negro sampled 20 DAE) for ammonium and nitrate the doses of coexistence was 13 and 58 KgN ha-1 and the values of pHR was 3,95 and 5,59, respectively. In test with different soil types (20 DAE), the dose of coexistence was lower with ammonium than nitrate, being in soil with lower clay content 18 e 41 KgN ha-1 and soil with higher clay content 15 e 27 KgN ha-1, respectively. The values of pHR for ammonium and nitrate were 4,69 and 6,08 in soil with lower clay content and 4,23 and 4,63 in soil with higher clay content, respectively. In this test the neutralizers alleviated acidification of the rhizosphere and nodulation was optimized. In test with leaf application of N, ammonium also more acidify the rhizosphere and promoted less nodulation (pHR 4,15 and 14 nodules plant-1) compared to nitrate (pHR 5,03 and 27 nodules plant-1). In the 6th experiment (20 DAE) the dose of 115 kgVO4 ha-1 allowed that highest dose of ammonium did not make changes in pHR, allowing also the dose of coexistence of 46 KgN ha-1 for ammonium as source of N. In all tests, the highest N rates from all sources completely inhibited nodulation, suggesting that these doses were the occurrence of others inhibiting factors independent of pH and not measured. / O feijoeiro pode adquirir nitrog?nio da mat?ria org?nica do solo, de adubos ou da fixa??o biol?gica do N2 atmosf?rico (FBN). Entretanto, nesta cultura o processo biol?gico tem apresentado baixa efici?ncia nas condi??es de campo. Em fun??o disso, muitos produtores n?o inoculam as sementes com estirpes eficientes de riz?bio, sendo a aduba??o a principal fonte de N para esta cultura. Al?m da aus?ncia da inocula??o, altas doses de N aplicadas no solo inibem a nodula??o e a FBN. No entanto, as causas para esta inibi??o n?o s?o totalmente esclarecidas, especialmente pelo fato do N ser absorvido na forma de nitrato (NO3 -) e am?nio (NH4 +). Considerando que a rizosfera da planta crescida com nitrato ? alcalinizada e com am?nio ? acidificada, este trabalho teve o objetivo de avaliar o efeito das altera??es de pH rizosf?rico (pHR), causadas pelo metabolismo destas fontes de N, no in?cio da forma??o de n?dulos. Os experimentos foram realizados em c?mara de crescimento com luminosidade m?dia de 400 Lux, fotoper?odo de 12/12 horas (luz/escuro) e temperatura de 25?C ? 2?C. As plantas foram crescidas em vasos com areia, solos com baixo (8%) e m?dio (25%) teor de argila e em solu??o nutritiva. No 1? ensaio (salinidade) foi verificado que o am?nio causou maior eleva??o da condutividade el?trica da areia (CE), obtendo-se na dose de 60 kgN ha-1 o valor de 1.655 ?S cm-1 com am?nio e de 1.301 ?S cm-1 com nitrato. No ensaio seguinte foram comparadas 2 cultivares contrastantes quanto ? capacidade nodular, que confirmaram a alta (Ouro Negro) e a baixa (Rio Tibagi) capacidade. Como entre as cultivares n?o ocorreram diferen?as expressivas nos valores de pHR, nos demais experimentos avaliou-se apenas a Ouro Negro. Neste ensaio e nos demais o am?nio foi a fonte de N que mais acidificou a rizosfera e inibiu a nodula??o. Atrav?s de an?lises de regress?o para cada fonte de N foi determinada a dose de inibi??o total da nodula??o (n?vel cr?tico), pHR nesta dose e a dose onde ocorreu 80% da m?xima nodula??o (dose de conviv?ncia). Em geral, foram observadas as menores doses de NC e de conviv?ncia com uso do am?nio do que com nitrato. No ensaio em areia (cv Ouro Negro coletada aos 20 DAE), para am?nio e nitrato as doses de conviv?ncia foram 13 e 58 kgN ha-1 e os valores de pHR 3,95 e 5,59, respectivamente. No ensaio em diferentes tipos de solo (20 DAE), a dose de conviv?ncia foi menor com am?nio do que com nitrato, sendo no solo com menor teor de argila 18 e 41 kgN ha-1 e no solo com maior teor de argila 15 e 27 kgN ha-1, respectivamente. J? os valores de pHR para am?nio e nitrato foram 4,69 e 6,08 no solo com menor teor de argila e 4,23 e 4,63 no solo com maior teor de argila, respectivamente. Neste ensaio os neutralizantes aliviaram a acidifica??o da rizosfera e otimizaram a nodula??o. No ensaio com aplica??o de N via foliar, o am?nio tamb?m acidificou a rizosfera e promoveu menor nodula??o (pHR 4,15 e 14 n?dulos planta-1) em rela??o ao nitrato (pHR 5,03 e 27 n?dulos planta-1). No 6? experimento (20 DAE) a dose de 115 kgVO4 ha-1 permitiu que na mais alta dose de am?nio o pHR n?o sofresse altera??es, permitindo tamb?m a dose de conviv?ncia de 46 kgN ha-1 para o am?nio. Em todos os ensaios, as mais altas doses de N de todas as fontes suprimiram a nodula??o, sugerindo que nestas doses ocorreram fatores inibidores independentes do pH e n?o mensurados.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2017-05-08T12:00:17Z No. of bitstreams: 2 Tese - Polianna Alves Silva Dias - 2017.pdf: 2130972 bytes, checksum: 17a85863b4938d2462080a2033d86cee (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-05-08T12:00:32Z (GMT) No. of bitstreams: 2 Tese - Polianna Alves Silva Dias - 2017.pdf: 2130972 bytes, checksum: 17a85863b4938d2462080a2033d86cee (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-05-08T12:00:32Z (GMT). No. of bitstreams: 2 Tese - Polianna Alves Silva Dias - 2017.pdf: 2130972 bytes, checksum: 17a85863b4938d2462080a2033d86cee (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-04-07 / In species rich in protein, like common bean, the nitrogen is considered as the most limiting nutrient in the development of the crop. One way to acquire the N by common bean is through biological nitrogen fixation (BNF). Despite its importance, there are no studies aiming the selection of common bean genotypes under rhizobia inoculation in multiple environments. Thus, the objectives of this studies were: to study the effect of interaction (GxF) of common bean elite lines with nitrogen fertilization and/or rhizobia inoculation; to select lines with high grain yield adaptability and stability and high agronomic performance when inoculated with rhizobia; to assess the variability of the elite lines for the nodulation traits; and to identify lines with superior nodulation traits under BNF cultivation. They were evaluated 19 carioca genotypes and 15 of the black group, in trials conducted separately by grain group. At first, experiments for the evaluation of agronomic traits were conducted at the states of Goiás, Paraná, Mato Grosso and at Distrito Federal, in three sowing seasons (rainy, winter and dry), in 2011 and 2012. Two trials were installed at each environment (location/sowing season/year), one with mineral nitrogen fertilization (80 kg N ha-1) and another with the inoculation of the seeds with Rhizobium tropici and R. freirei strains. The grain yield, sieve yield, 100 grains weight, plant architecture, lodging tolerance and the reaction to anthracnose and angular leaf spot were evaluated. Then, the lines were evaluated during rainy/2013 and winter/2014 seasons, at Santo Antônio de Goiás/GO, under rhizobia inoculation and nitrogen fertilization, in which they were assessed the nodule number, nodule dry and specific weight, nodules activity and shoot dry weight. The relative nodulation index was used on the selection of lines for the nodulation traits. Individual and combined analyses of variance were performed and they were estimated the Spearman correlations and the coincidence index on the selection of the best 30% lines with inoculation and with N fertilization. Grain yield adaptability and stability analyses were performed by the Nunes graphical method. Even though the interaction GxF was significant for some traits in both grain groups, it did not influence on the selection of the best genotypes. The lines of both groups are more productive when fertilized with mineral N, however, the carioca lines lodge less under BNF. The carioca line CNFC 15086 and the cultivars of black group BRS FP403 and BRS Esteio are indicated for cultivation under both N sources. The lines of both grain groups show higher performance for nodulation traits when inoculated. The genotypes BRS Sublime, CNFC 15010 and CNFC 15003 of the carioca group, and BRS Campeiro and CNFP 15177 of the black group are selected for the nodulation traits. / Em espécies ricas em proteína, como o feijoeiro-comum, o nitrogênio é tido como o nutriente mais limitante ao desenvolvimento da cultura. Uma das formas de aquisição do N pelo feijoeiro-comum é via fixação biológica de nitrogênio (FBN). Apesar de sua importância, inexistem estudos para seleção de genótipos de feijoeiro-comum sob inoculação com rizóbio em múltiplos ambientes para cultivo. Os objetivos do trabalho foram: estudar o efeito da interação (GxF) de linhagens elite de feijoeiro-comum com a adubação nitrogenada mineral e/ou inoculação com rizóbio; selecionar linhagens com alta adaptabilidade e estabilidade produtiva e alto desempenho agronômico quando inoculadas com rizóbio; avaliar a variabilidade das linhagens para os caracteres relativos à nodulação; e identificar linhagens com características de nodulação superiores para utilização em cultivo sob FBN. Foram avaliados 19 genótipos do grupo carioca e 15 do grupo preto, em ensaios separados por grupo de grão. Inicialmente foram feitos experimentos para avaliação de caracteres agronômicos, nos Estados de Goiás, Paraná, Mato Grosso e no Distrito Federal, em três épocas de semeadura (águas, inverno e seca), em 2011 e 2012. Foram instalados dois ensaios em cada ambiente (local/época de semeadura/ano), um com adubação nitrogenada mineral (80 kg ha-1 de N) e outro com inoculação das sementes com estirpes de Rhizobium tropici e R. freirei. Foram avaliadas a produtividade de grãos, rendimento de peneira, massa de 100 grãos, arquitetura de plantas, tolerância ao acamamento e a reação à antracnose e mancha-angular. Posteriormente, as linhagens foram avaliadas nas safras das águas/2013 e inverno/2014, em Santo Antônio de Goiás/GO, com inoculação de rizóbio e adubação com N mineral, em que foram avaliados o número de nódulos, a massa de nódulos secos e a específica, atividade de nódulos e massa da parte aérea seca. O índice de nodulação relativa foi utilizado na seleção de linhagens quanto aos caracteres de nodulação. Foram realizadas análises de variância individuais e conjuntas e estimadas as correlações de Spearman e o índice de coincidência da seleção das 30% melhores linhagens com inoculação e com N mineral. Foram feitas análises de adaptabilidade e estabilidade produtiva pelo método gráfico de Nunes. A interação GxF foi significativa para alguns caracteres em ambos os grupos de cores, porém não influenciaram na seleção das melhores linhagens. As linhagens de ambos os grupos são mais produtivas sob adubação com N mineral, porém, as do grupo carioca acamam menos sob FBN. A linhagem carioca CNFC 15086 e as cultivares do grupo preto BRS FP403 e BRS Esteio são indicadas para o cultivo em ambas as fontes de N. As linhagens de ambos os grupos apresentam melhor desempenho para os caracteres de nodulação quando inoculadas. Os genótipos do grupo carioca BRS Sublime, CNFC 15010 e CNFC 15003 e, os do grupo preto, BRS Campeiro e CNFP 15177 são selecionados quanto aos caracteres de nodulação.

Im Mittelpunkt dieser Arbeit steht die Untersuchung des Typ III-Sekretionssystem (T3SS) bei Bradyrhizobium japonicum USDA110. Im ersten Teil der Arbeit wird die Regulation der Gene des Typ III-Sekretionssystems in B. japonicum beschrieben. Dabei wurde die tts-Box, als neuartige Promotorsequenz für die Gene des T3SS und sekretierter Proteine charakterisiert. Mittels Expressionsanalysen konnte die Aktivität von 34 Genregionen downstream der tts-Boxen in Abhängigkeit von Flavonoiden gezeigt werden. Auch in Symbiose, in frühen Infektionsstadien und in reifen Knöllchen von verschiedenen Wirtspflanzen wurde die Expression ausgewählter Gene nachgewiesen. Der zweite Teil der Arbeit widmet sich der Analyse der sekretierten Proteine von B. japonicum. Über 100 Proteine wurden im Überstand von Kulturen nachgewiesen, wovon 68 Proteine durch Massenspektrometrie identifiziert werden konnten. Zusätzlich wurden 12 Proteine identifiziert, die in Abhängigkeit des T3SS sekretiert werden. Im dritten Teil der Arbeit wurden die sekretierten Proteine NopE1 und NopE2 näher untersucht und als bona-fide Effektoren nachgewiesen. Die rekombinant produzierten Effektoren NopE1 und NopE2 wurden biochemisch charakterisiert. Für die Domäne unbekannter Funktion (DUF1521) wurde eine spezifische Selbstspaltungsaktivität in Gegenwart von Calcium gezeigt. Nachweislich ist diese Aktivität relevant für die Symbiose. Somit konnte der Proteindomäne mit bisher unbekannter Funktion eine biochemische Funktion zugeordnet werden. Im letzten Teil der Arbeit wurden die Untersuchungen an dieser Domäne auf weitere Proteine ausgedehnt. Für das putative Effektorprotein VIC_001052 aus V. coralliilyticus, dem Verursacher der Korallenbleiche bei Pocilla damicornis, wurde ebenfalls die in vitro Calcium-induzierte Selbstspaltungsaktivität gezeigt. Aufgrund der konservierten Selbstspaltungsfunktion wurde die DUF1521-Domäne in metal-ion inducible autocleavage- (MIIA)- Domäne umbenannt.:I. Einleitung Rhizobien-Leguminosen-Interaktion Proteinsekretionssysteme II. Zusammenfassung der Forschungsergebnisse 1. Untersuchung der Expression des Typ III-Sekretionssystems in Knöllchen und Analyse des tts-Box-Promotors 2. Identifizierung sekretierter Proteine von Bradyrhizobium japonicum 3. Untersuchung der sekretierten Proteine NopE1 und NopE2 4. Untersuchung von konservierten MIIA-Domänen III. Diskussion IV. Zusammenfassung V. Literaturverzeichnis VI. Anhang VII. Publikationen

MSCAGR (Plant Production) / Department of Plant Production / Tepary bean (Phaseolus acutifolius) is an important food legume originating from South America and the South-western parts of the United States. The crop is produced in many countries worldwide including South Africa. It is highly tolerant to drought and the seed contains a wide range of vitamins, minerals and protein of high nutritional quality. The genetic base of tepary bean is narrow but can be widened by chemical mutagenesis. However, there are no reports on the impact of chemical mutagenesis on the root nodulation and seed storage proteins in tepary bean. Therefore, this study was designed to examine root nodulation attributes and seed storage proteins of three tepary bean genotypes in the early mutagenic generations (M2 to M4) derived through treatment with varying doses (0.0, 0.5, 1.0, 1.5 and 2.0 v/v) of ethyl methanesulfonate (EMS). The experiment on root nodulation attributes was laid out as a 3 x 5 x 3 (genotypes x EMS doses x mutant generations) factorial design replicated three times. At harvest, shoot height (SHT), primary root length (PRL), dry weights (shoot, root and nodule), number of nodules per plant (NNP) and grain yield components such as the number of pods per plant (NPP) and number of seeds per pod (NSP) were measured. Highly significant (P≤0.01) dose effects were observed for SHT, PRL, shoot dry weight (SDW) and root dry weight (RDW). Highly significant (P≤0.01) interaction effects of mutant generation x genotype x dose were observed for NSP. A highly significant (P≤0.01) positive linear relationship was observed between the NNP and nodule dry weight (NDW). Increase in the PRL suggested that tepary bean mutants could be important in drought tolerance. EMS treatment led to an enhanced partitioning of dry matter (assimilates) to the shoots and roots. There was a three fold increase in most of the root nodulation traits at the 0.5% EMS dose.The Kjeldahl method was used for crude protein determination whereas the sodium dodecyl sulphate – polyacrylamide gel electrophoresis (SDS PAGE) was utilized in determining the protein banding patterns of the bean. There were highly significant (P≤0.01) differences among the genotypes in crude protein accumulation. Highly significant (P≤0.01) mutant generation x genotype x dose were observed for seed protein accumulation. ‘Genotype 3’ attained the highest protein content (24.23%) at 1.5% EMS dose in the M4 generation. EMS doses ≥0.5% positively stimulated protein accumulation in all genotypes but high EMS doses (2.0%) depressed protein content. There were significant variations in seed storage protein profiles among the genotypes and mutant generations. ‘Genotype 6’ showed a distinct 15.0kDa protein fragment which was absent in the majority of the remaining genotypes. The presence of distinct protein subunits in the three genotypes could be used in varietal / NRF

Soybean (Glycine max [L.] Merr.) has become one of the main agricultural grain crops produced in the United States. Soybean production continues to increase in high-yield environments throughout the U.S. New innovations are required to sustain gains in soybean yield potential. Field experiments were conducted at the Delta Research and Extension Center in Stoneville, MS in 2014 and 2015 to evaluate soybean aboveground biomass and grain yield response to supplemental N fertilization in a high-yielding environment on two soil textures commonly cropped to soybean in Mississippi. Greenhouse studies were conducted in 2016 at the Delta Research and Extension Center in Stoneville, MS to evaluate the influence of supplemental N fertilization on nodule formation and belowground biomass of soybean on two soil textures commonly cropped to soybean in Mississippi.

Invasive plants can displace native species, deteriorate native forest, and change plant communities and ecosystem functions. Native plant populations are fundamentally impacted by invasive species because of the interactions between invasive species and native plants. This study focuses on understanding the extent, mechanisms and consequences of interaction between a non-indigenous invader Ailanthus altissima and its functionally similar native species Robinia pseudoacacia in the Mid-Appalachian region, from an individual scale to a regional scale. These two subject species are common and coexist in early-successional eastern deciduous forest. The interactions between these two common species are important to community structure and canopy tree regeneration. To address the type and extent of interactions of these two species, a greenhouse experiment utilizing various species proportions, nutrient levels and seed sources was performed. In addition, a common-garden experiment with various species densities and proportions over three consecutive growing seasons was performed in a more natural condition than that of the greenhouse experiment. We found at the seedling stage, the dominant interaction was competition, and R. pseudoacacia was the winner both above- and belowground. The allelopathic compounds of A. altissima may have inhibited nodulation of R. pseudoacacia. Ailanthus altissima seedlings from its native region had slightly stronger competitive abilities compared with the seedlings from its invaded range. In the common garden experiment, R. pseudoacacia plants grew quicker than A. altissima, but A. altissima inhibited the growth of R. pseudoacacia by interspecific competition. The negative impact of A. altissima on R. pseudoacacia became larger as time progressed. To assess the community-level consequences of the two species, we conducted a forest mapping and a complete target-tree-based forest survey, and analyzed regional-scale data from the Forest Inventory Analysis Data Base. The two target species were significantly associated with themselves and with each other. Community species composition and diversity were significantly different across sites. A negative impact of both species on the understory community diversity and tree regeneration at the neighborhood scale was detected; while at a regional level, tree diversity in the FIA plots with either A. altissima or R. pseudoacacia was higher than the reference plots. / Ph. D.