The legume-rhizobia relationship is an important symbiosis. Studies have found variation in specificity and the functionality of symbiotic specificity can vary among plants of the same species and among rhizobia, as well as in concert with geographical variation. Here, we examined the diversity and geographic structure of rhizobia nodulating Chamaecrista fasciculata, which grows throughout the east-central U.S. and is symbiotic with Bradyrhizobium species. We investigated the association of geography and soil variables on rhizobial diversity by sampling plant nodules and soil across Mississippi and evaluated variation in rhizobia housed in different nodules of individual plants. Using nifH and truA, we conducted phylogenetic analyses and mantel tests but did not find that geography correlates with genetic diversity. However, soil variables and genetic distance were significantly correlated. Lastly, we found that rhizobia across nodules of the same plant varied substantially. These results contribute to the knowledge of rhizobial assemblages in natural populations.

EVALUATION THE NITROGEN NEEDS AND EFFICIENCY OF RHIZOBIA STRAINS TO PROVIDE NITROGEN TO CHIPILIN (Crotalaria Longirostrata HOOK. AND ARN.) FEBRUARY OF 2013 FATIMA DEL ROSARIO CAMARILLO CASTILLO, B.A., AUTONOMOUS UNIVERSITY OF CHAPINGO M.A., UNIVERSITY OF MASSACHUSETTS AMHERST Directed by: Professor Francis X. Mangan Chipilin (Crotalaria Longirostrata) is a leguminous plant native to Central America and Southern Mexico and used in the preparation of traditional dishes in this region. Starting in 2009, farmers in Massachusetts have been growing chipilin with a weekly production of 800 kg∙ha-1. However, as much as 300 kg∙ha-1 of nitrogen has been necessary to apply to the soil in order to obtain a marketable leaf quality. With the goal to determine the nitrogen requirements of chipilín and to quantify the capacity of selected stains to infect and provide nitrogen for this crop, two-field experiments were conducted at the UMass Research farm at Deerfield, Massachusetts, in an occum fine sandy loam soil (coarse-loamy, mixed, mesic Fluventic Dystrudept) soil as a randomized complete bock design with five replications. For the field trial in 2011, nitrogen rates were (kg∙ha-1): 40, 80, 120, 160, 200 and 240 and 0, 40, 80, 120, 160, 200, 240 and 280 in 2012 in combination with four Rhizobia strains: Bradyrhizobium sp. (Vigna), Rhizobium leguminosarum biovar, Bradyrhizobium USDA 3384 and no Rhizobia were the treatments. Based on the results obtained, nitrogen fertilizer application of 80 kg∙ha-1 was economically sufficient for chipilin to reach optimum yield. However higher nitrogen rates are needed to obtain marketable leaf color and quality. Additionally a greenhouse experiment set up as a factorial experiment with five replications was conducted with seven nitrogen concentrations (mg N∙L-1)-; 0, 26.25, 52.5, 105, 157.5, 210 and 262.5 mg∙L1 and the three Rhizobia strain for the previous experiment plus Bradyrhizobium USDA 2370 as treatments. Results suggest from Bradyrhizobium USDA 3384 is not an efficient strain for chipilin, and Rhizobium leguminosarum biovar potentially may provide the most nitrogen of the strains evaluated. In the greenhouse trial, nodules number per plant decreased with the increase in nitrogen applications, but this was not the case in the field trial in 2012. Nodules were found on the root of chipilin plants in the control. This is suspected to be due to one of the following possibilities: Rhizobia inoculum presence in the seed, Rhizobia in the soil (in the field trial) or contamination during the setup of the experiment.

Symbiotic interactions among various organisms are often necessary for one or both individual's survival. These symbiotic relationships must be considered in restoration projects to allow for the successful establishment of the species. Rhizobia are nitrogen-fixing bacteria found in symbiotic relations with legumes. By utilizing this relationship, restoration practitioners can establish native legume species more successfully while repopulating soil microorganisms into degraded soils. Despite the potential benefits a rhizobium inoculant can have on restoration efforts, minimal research has been done to understand the impacts this treatment has on specific species and the systems they are employed within. Our research goal was to assess the efficacy of applying a commercial rhizobium product (EXCEED ®) and indigenous rhizobium strains on two lupine species (Lupinus argenteus Pursh and Lupinus sericeus Pursh), commonly used for rangeland seedings in the Great Basin region of the western United States. We conducted laboratory and field trials to meet this research goal, with the results of the laboratory experiments shared in chapter 1 and findings from the field reported in chapter 2. In chapter 1, we evaluated in the laboratory whether indigenous rhizobia strains could be isolated, cultured, and applied as a liquid inoculant or a seed coating to induce root nodulation and increase plant growth. The performance of these inoculums was compared against the commercial rhizobium product. Additionally, we tested in a trial if compost could be applied within the seed coating to improve the efficacy of the rhizobium treatment. Our research demonstrated that the commercial inoculum induced root nodulation, and in one of three trials, this treatment improved plant growth. We also found indigenous strains effectively formed nodules on the plant roots when applied through a liquid culture or a seed coating. However, the number of root nodules and the presence of a pink color (indicating nitrogen fixation) were typically higher in the commercial product than in the indigenous strains when applied through a seed coating. These short-term laboratory studies generally provided minimal evidence that rhizobia impacted plant growth. However, data indicated that having compost in the coating alone improved shoot biomass by 33% (P = 0.025). In chapter 2, research assessed the performance of the same rhizobia inoculums tested in the laboratory trials on a mine in northern Utah at two waste-rock sites, one comprised of crushed waste rock and the other made of waste rock amended with topsoil. One year after seeding, we had high plant recruitment at both study sites, and there were more plants, which were more vigorous, in the amended site (P<0.001). These results demonstrate that reclamation efforts on mineland overburden can be improved when topsoil is incorporated into the growing medium. At this stage in the study, there was no difference in plant establishment and vigor between any seed treatments, but future research is planned to assess these metrics in the next growing season. The lack of improvement in plant growth from a rhizobia treatment in some of our laboratory and field trials may be due to the short period of these studies. Nodules that form on mature root systems provide more nitrogen-fixing benefits than those formed on immature roots. Hence, future research should consider conducting trials for more extended periods to understand how the treatments influence the growth of mature plants. Because we found in the laboratory that the rhizobia inoculums were successful in nodulating the test species, we anticipate that future studies will find that these treatments can improve plant performance and subsequently restoration success.

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Les béta-rhizobia sont des symbiotes de légumineuses retrouvées principalement associés au genre Mimosa. Les études des symbiotes de Mimosa pudica révèlent différents profils de diversité au sein des alpha (Rhizobium spp) et béta-rhizobia (Burkholderia, Cupriavidus) le long de la ceinture tropicale, les béta-rhizobia étaient toujours majoritaires dans les nodosités de cette plante hôte. Dans ce travail de thèse, nous avons étudié cette spécificité d'association béta-rhizobia/Mimosa pudica, par une approche couplant l'étude des traits symbiotiques bactériens à l'analyse des profils d'expression de leurs génomes dans les premières étapes de la symbiose, et en comparaison avec les alpha-rhizobia. Nous avons analysé les traits symbiotiques (compétitivité pour la nodulation, efficience symbiotique) au niveau intra et interspécifique de 4 espèces de béta-rhizobia et 4 d'alpha-rhizobia. Si l'efficience symbiotique est similaire parmi toutes les souches testées, différents niveaux de compétitivité ont été trouvés selon l'espèce, B. phymatum et B. tuberum étant les plus compétitives. Les tests effectués sur différentes variétés de M. pudica montrent un effet variétal sur la compétitivité de C. taiwanensis. Les traits symbiotiques mesurés expliquent en partie les profils de diversité des symbiotes de M. pudica dans les zones d'origine (Amérique du Sud) ou en zone introduite (Taiwan). Les transcriptomes de trois bactéries ayant des traits symbiotiques différents (B. phymatum STM815, C. taiwanensis LMG19424 et R. mesoamericanum STM3625) ont été comparés (par RNAseq), pour relier les différentes réponses induites par les exsudats racinaires aux traits symbiotiques de chaque rhizobium. Chaque bactérie développe une stratégie spécifique liée à ses traits symbiotiques et à l'origine de la symbiose dans son groupe bactérien. / Beta-rhizobia are legume symbionts mainly found associated to the Mimosa genus. Diversity studies of Mimosa pudica symbionts in native and introduced areas reveal different diversity patterns of alpha (Rhizobium spp) and beta-rhizobia (Burkholderia, Cupriavidus), with beta-rhizobia being always the main symbionts in the nodules of this legumes species. In this thesis we have studied the symbiotic specificity between beta-rhizobia and M. pudica (and the comparison with alpha-rhizobia) by a dual approach combining the study of bacterial symbiotic traits and the analysis of their transcriptomes in the first steps of symbiosis. We analysed symbiotic traits (nodulation competitiveness, symbiotic efficiency) at intra and interspecific levels on four species of beta-rhizobia and four of alpha-rhizobia. If symbiotic efficiency is similar among all strains, different levels of competitiveness were measured with a strong strain effect largely explained by the species affiliation, B. phymatum and B. tuberum being the most competitive species. Tests on different M. pudica varieties showed an impact on the competitiveness of C. taiwanensis. Symbiotic traits explained in part the symbiont patterns observed in diversity studies in French Guiana (M. pudica native area) and Taiwan (introduced). Root-exudates induced transcriptomes of three bacteria (two beta--rhizobia: B. phymatum STM815, C. taiwanensis LMG19424 and one alpha, R. mesoamericanum STM3625) with contrasted symbiotic traits were compared (by RNAseq). Each bacterium develops a specific strategy linked to its symbiotic traits and the origin of symbiosis in its bacterial group.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2017-01-12T10:40:03Z No. of bitstreams: 2 Dissertação - José Eduardo Barbosa de Souza - 2015.pdf: 3247331 bytes, checksum: b9d7e1a78b217daaca27c536a06e8b1d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-01-12T10:40:35Z (GMT) No. of bitstreams: 2 Dissertação - José Eduardo Barbosa de Souza - 2015.pdf: 3247331 bytes, checksum: b9d7e1a78b217daaca27c536a06e8b1d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-01-12T10:40:36Z (GMT). No. of bitstreams: 2 Dissertação - José Eduardo Barbosa de Souza - 2015.pdf: 3247331 bytes, checksum: b9d7e1a78b217daaca27c536a06e8b1d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2015-11-18 / SOUZA, J. E. B. Rhizobium tropici and Azospirillum brasilense Co-inoculation in common bean aiming at productivity increasing and costs reduction. 2015. 85 f. Dissertation (Masters in Agronomy: Soil and Water) – Escola de Agronomia, Universidade Federal de Goiás, Goiânia, 20151. The common bean (Phaseolus vulgaris L.) has great importance for the Brazilian population, contributing to about 20-28 % of the daily protein necessity. In the Midwest agricultural scenario, the common bean is present in different production systems, from those of low use of supplies to the high-performance and highly intensive technified systems. However, the production costs have been increasing, especially nitrogen fertilizers. An alternative for cost reducing is the bacteria capable of performing biological nitrogen fixation (BNF), associated with the plant growth promoter bacteria. The objective of this study was to evaluate the common bean agronomic and economic performance co-inoculated with Rhizobium tropici and Azospirillum brasilense. The experiments were conducted under field conditions for two consecutive years in the winter crop. The Pérola crop of common bean was subjected to the following treatments: T1-treatment control (without inoculation and fertilization); T2- nitrogen Witness with 20 kg ha-1 at planting and 60 kg ha-1 in the V2/V3 phenological stage; T3 Seed Inoculation with two doses of R. tropici (SEMIA 4080); T4 seed inoculation with two doses of R. tropici (SEMIA 4080) and another dose of A. brasilense (AbV-5); T5- seed inoculation with two doses of R. tropici (SEMIA 4080) two more doses of A. brasilense (AbV-5); T6- seed inoculation with two doses of R. tropici (SEMIA 4080), and pulverization of two doses of A. brasilense (AbV-5) in the V2/V3 phenological stage; T7- seed inoculation with two doses of R. tropici (SEMIA 4080) and the pulverization of three doses of A. brasilense (AbV-5) in the V2/V3 phenological stage. The treatments were arranged in randomized lineation blocks with four repetitions. In R6 phenological stage, nodulation and development parameters of the crop were evaluated. Data were submitted to variance analysis and the average compared by the Scott-Knott test at 5% probability. The T7 treatment provided a significant increase in the number of nodes, number of leaves, leaf area, dry weight of shoot and root parts, number of pods and number of grains and production related to the control treatment and among the done treatments in combination of R. tropici and A. brasilense the best performance. For the evaluation of the common bean crop production cost, it was used information from the Federation of Agriculture and Livestock of Goiás (FAEG) for the years 2013 and 2014. For the average of the four experiments, the seed inoculation treatment with two doses of R. Tropici and the pulverization after planting with three doses of V2/V3 phenological stage A. brasilense in the showed the average financial return of R$ 3,58 for every R$ 1,00 invested, that is, an increase of 358% on the investment, which is numerically higher than the average of the other treatments. The co-inoculation R. tropici and A. brasilense technology is an option for the producer for partial and / or total replacement of nitrogen chemical sources for the common bean crop. / SOUZA, J. E. B. Co-inoculação de Rhizobium tropici e Azospirillum brasilense no feijoeiro-comum visando aumento de produtividade e redução de custo de produção. 2015. 85 f. Dissertação (Mestrado em Agronomia: Solo e Água) – Escola de Agronomia, Universidade Federal de Goiás, 2015.1 O feijoeiro-comum (Phaseolus vulgaris L.) possui grande importância para a população brasileira, contribuindo com cerca de 25% da necessidade diária de proteína. No cenário agrícola do Centro-Oeste, o feijoeiro-comum está presente em variados sistemas de produção, desde aqueles de baixo uso de insumos até sistemas de alto rendimento e altamente tecnificado. Porém os custos de produção vêm aumentando, principalmente fertilizantes nitrogenados. Uma alternativa para diminuição dos custos é a utilização de bactérias capazes de realizar fixação biológica do nitrogênio (FBN), associados a bactérias promotoras do crescimento de plantas. O objetivo deste trabalho consistiu em avaliar o desempenho agronômico e econômico do feijoeiro-comum co-inoculado com Rhizobium tropici e Azospirillum brasilense. Os experimentos foram conduzidos sob condição de campo por dois anos consecutivos em safra de inverno. A cultivar Pérola de feijoeiro-comum foi submetida aos seguintes tratamentos: T1-Tratamento controle (sem inoculação e adubação); T2-Testemunha nitrogenada com 20 kg ha-1 no plantio e 60 kg ha-1 na fase fenológica V2/V3; T3- Inoculação da semente com duas doses de R. tropici (SEMIA 4080); T4- Inoculação da semente com duas doses de R. tropici (SEMIA 4080) mais uma dose de A. brasilense (AbV-5); T5- Inoculação da semente com duas doses de R. tropici (SEMIA 4080) mais duas doses de A. brasilense (AbV-5); T6- Inoculação da semente com duas doses de R. tropici (SEMIA 4080), mais pulverização de duas doses de A. brasilense (AbV-5) na fase fenológica V2/V3; T7- Inoculação da semente com duas doses de R. tropici (SEMIA 4080), mais pulverização de três doses de A. brasilense (AbV-5) na fase fenológica V2/V3. Os tratamentos foram dispostos em delineamento de blocos ao acaso com 4 repetições. Na fase fenológica R6 foram avaliados parâmetros de nodulação e de desenvolvimento da cultura. Os dados foram submetidos à análise de variância e as médias comparadas pelo teste de Scott-Knott a 5% de probabilidade. O tratamento T7 proporcionou um aumento significativo do número de nódulos, número de folhas, área foliar, massa seca da parte aérea e raiz, número de vagens e número de grãos e produção referente ao tratamento controle e dentre todos os tratamentos realizados em combinação de Rhizobium tropici e Azospirillum brasilense o de melhor performance. Para avaliação do custo da produção da cultura do feijoeiro-comum, foi utilizado as informações da Federação da Agricultura e Pecuária de Goiás (FAEG) para os anos 2013 e 2014. Para a média dos quatro experimentos realizados, o tratamento inoculação da semente com duas doses de R. tropici mais a pulverização após plantio com três doses de A. brasilense na fase fenológica V2/V3 apresentou retorno médio financeiro de R$3,58 para cada real investido, ou seja, um incremento de 358% sobre o investimento, sendo superior numericamente as médias dos demais tratamentos. A tecnologia da co-inoculação de R. tropici e A. brasilense é uma opção para o produtor para substituição parcial e ou total de fontes químicas nitrogenadas para a cultura do feijoeiro-comum.

Submitted by Mario BC (mario@bc.ufrpe.br) on 2017-02-20T12:53:49Z No. of bitstreams: 1 Suelane de Melo Dias.pdf: 1653730 bytes, checksum: 9a680e841961b44f37985e8341a0bd0a (MD5) / Made available in DSpace on 2017-02-20T12:53:49Z (GMT). No. of bitstreams: 1 Suelane de Melo Dias.pdf: 1653730 bytes, checksum: 9a680e841961b44f37985e8341a0bd0a (MD5) Previous issue date: 2015-02-27 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / This study aimed to characterize Morphophysiologically native Rhizobia of Fabaceae forage Caatinga, Mimosa tenuiflora (Willd) Poiret, (Jurema preta), Macroptilium atropurpureum (OC.) Urb (Siratro) and Desmanthus pernambucanus (L.) Thellung (jureminha) in selected soils in areas of Caatinga located in the municipalities of Sertânia, Arcoverde and São Bento do Una- Pernambuco. Soil samples were collected at random in three areas in profile 0 to 20 cm depth, designed for the planting of Fabaceae, with the purpose of producing nodules. After obtaining the nodules and replication of the bacteria in the laboratory colonies were characterized as the time of growth and cultural characteristics of Rhizobia isolates. Tests were also made in vitro tolerance of Rhizobia isolated in different variations in salinity, temperature and pH. Based on physiological data we calculated the diversity indices, evenness, dominance and species richness, then dendrograms generated by the UPGMA algorithm. In cultural evaluation revealed that the isolates showed the hallmarks of flat lifting colonies, low to moderate production of exopolysaccharides, color ranging from white to cream and smooth surface in accordance with each individual. Physiological tests of the abiotic stress resistance showed that the natives isolated from Mimosa tenuiflora were more resistant when grown in soils from the municipality of Sertânia and isolates Macroptilium atropurpureum and Desmanthus pernambucanus had high resistance to high temperatures, regardless of place of farming. For Species diversity analysis can be seen that the Caatinga area evaluated in São Bento do Una showed lower species diversity. Native rhizobia in the areas of collections in Pernambuco semiarid feature high resistance to abiotic stress caused by temperatures up to 40 °C, variations in salinity and pH. / Objetivou-se caracterizar morfofisiologicamente rizóbios nativos das fabáceas forrageiras, Mimosa tenuiflora (Willd) Poiret, (Jurema preta), Macroptilium atropurpureum (OC.) Urb (Siratro) e Desmanthus pernambucanus (L.) Thellung (Jureminha), em áreas de Caatinga localizadas nos municípios de Sertânia, Arcoverde e São Bento do Una no Estado de Pernambuco. Foram coletadas amostras de solo nas três áreas no perfil de 0 a 20 cm de profundidade, destinadas para o plantio das fabáceas, com o propósito de produção de nódulos. Após a obtenção dos nódulos e replicação das bactérias em laboratório as colônias foram caracterizadas quanto ao tempo de crescimento e características culturais dos isolados. Também foram feitos testes de tolerância, in vitro, com diferentes variações de salinidade, temperatura e pH. Baseados nos dados fisiológicos foram calculados os índices de diversidade, equitabilidade, dominância e riqueza de espécies, em seguida gerados dendrogramas pelo algoritmo UPGMA. Na avaliação cultural observou-se que os isolados formaram colônias com elevação plana, moderada produção de exopolissacarídeos, coloração variando de creme a branca e superfície lisa de acordo com cada isolado. Os testes fisiológicos de resistência a estresses abióticos mostraram que os isolados nativos de Mimosa tenuiflora foram mais resistentes quando cultivados nos solos provenientes do município de Sertânia e que os isolados de Macroptilium atropurpureum e Desmanthus pernambucanus tiveram elevada resistência a altas temperaturas, independente do local de cultivo. A área de Caatinga avaliada em São Bento do Una apresentou menor diversidade de espécies em relação às demais áreas. Os rizóbios nativos das áreas de coletas no Semiárido pernambucano apresentam elevada resistência ao estresse abiótico causado por temperaturas até 40 °C, variação na salinidade e pH.

Submitted by Jean Medeiros (jeanletras@uepb.edu.br) on 2016-05-05T13:54:46Z No. of bitstreams: 1 PDF - Daniela Duarte Barbosa.pdf: 2159661 bytes, checksum: 3e6acd4ae88f0d55064e106e8844dce7 (MD5) / Approved for entry into archive by Secta BC (secta.csu.bc@uepb.edu.br) on 2016-07-21T21:06:43Z (GMT) No. of bitstreams: 1 PDF - Daniela Duarte Barbosa.pdf: 2159661 bytes, checksum: 3e6acd4ae88f0d55064e106e8844dce7 (MD5) / Approved for entry into archive by Secta BC (secta.csu.bc@uepb.edu.br) on 2016-07-21T21:06:55Z (GMT) No. of bitstreams: 1 PDF - Daniela Duarte Barbosa.pdf: 2159661 bytes, checksum: 3e6acd4ae88f0d55064e106e8844dce7 (MD5) / Made available in DSpace on 2016-07-21T21:06:56Z (GMT). No. of bitstreams: 1 PDF - Daniela Duarte Barbosa.pdf: 2159661 bytes, checksum: 3e6acd4ae88f0d55064e106e8844dce7 (MD5) Previous issue date: 2016-03-10 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Peanut (Arachis hypogaea L.) is a herbaceous oilseed original in Latin America and cultivated in many regions of Brazil due to great capacity for environmental adaptation. But some biotic and abiotic environmental factors such as water stress, affect the peanut production capacity, however negative economic impacts that vary depending on the duration of the drought and the phenological phase of the plants. In this context aimed to evaluate the interaction of nitrogen-fixing microorganisms, as promoters of tolerance to drought in three peanut genotypes, assessing physiological and vegetative growth parameters. We used three genotypes of peanut and two cultivars (BRS Havana and CNPA 76 AM) and an advanced line (2012-4), the treatments were formed from the inoculation of three strains of rhizobia (SEMIA 6144, 123-10A and SEMIA 4077) , a nitrogenous chemical source (ammonium sulfate) and without nitrogen witness and two water regimes. The experimental design was completely randomized with factorial 3 x 5 x 2 with 6 repetitions. Data were analyzed using the statistical program SISVAR version 5.6, which were submitted to variance analysis by T test and comparison of means by Tukey test at 5% significance. The variables of gas exchange were affected by drought and decreased the plant height, shoot dry weight, dry weight of nodules and number of nodes. The drought also reduced gas exchange in peanut genotypes, however, the rhizobia mitigated the effects of drought. There was an increase in proline content in plants under water stress and antioxidant enzymes acted in accordance with the needs of the plant defense mechanisms. The genotypes studied were tolerant to drought in the presence of strains 123-10A and SEMIA 6144, and 123-10A was more responsive in most of the variables analyzed. / O amendoim (Arachis hypogaea L.) é uma oleaginosa herbácea originária da América Latina e cultivada em várias regiões do Brasil, por sua grande capacidade de adaptação ambiental. Porém, alguns fatores ambientais bióticos e abióticos, como o estresse hídrico, afetam a capacidade de produção do amendoim, desencadeando impactos econômicos negativos, que variam dependendo da duração da estiagem e da fase fenológica das plantas. Nesse contexto, objetivou-se avaliar a interação de microrganismos fixadores de nitrogênio, como promotores de tolerância ao déficit hídrico em três genótipos de amendoim, avaliando-se parâmetros fisiológicos e de crescimento vegetativo. Foram usados três genótipos de amendoim, sendo duas cultivares (BRS Havana e CNPA 76 AM) e uma linhagem avançada (2012-4), os tratamentos foram formados a partir da inoculação de três isolados de rizóbio (SEMIA 6144, 123-10A e SEMIA 4077), uma fonte química nitrogenada (sulfato de amônia) e a testemunha sem nitrogênio e dois regimes hídricos. O delineamento experimental foi inteiramente casualizado com fatorial de 3 x 5 x 2 com 6 repetições. Os dados obtidos foram analisados por meio do Programa estatístico SISVAR versão 5.6, os quais foram submetidos à análise de variância pelo teste T e a comparação de médias pelo de Teste de Tukey a 5% de significância. As variáveis de trocas gasosas foram afetadas pelo déficit hídrico e houve redução da altura de planta, massa seca da parte aérea, peso seco de nódulos e número de nódulos. O déficit hídrico reduziu também as trocas gasosas nos genótipos de amendoim, contudo, os rizóbios mitigaram os efeitos do déficit hídrico. Houve aumento no teor de prolina nas plantas sob restrição hídrica e as enzimas antioxidantes atuaram de acordo com as necessidades dos mecanismos de defesa das plantas. Os genótipos estudados foram tolerantes ao déficit hídrico na presença das estirpes 123-10A e SEMIA 6144, sendo que 123-10A foi mais a responsiva na maioria das variáveis analisadas.