How are nitrogen fixation rates regulated in legumes?

Schulze, Joachim

doi:10.1002/jpln.200320358

Cited by 137 publications

(113 citation statements)

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“…Further, most studies of bacteroid physiology are purely mechanistic and focus on single nodules, rarely if ever considering how bacteroid traits expressed in one nodule might influence the trait expression and performance of strains in other nodules. In contrast, empirical research on the regulation of nitrogen fixation adopts the plant's perspective and assumes plant control (e.g., Schulze 2004). We suggest that our approach can usefully merge these two perspectives by integrating evolutionary theory with a mechanistic approach to control and regulation of the symbiosis.…”

Section: Control and Outside Options In Biological Marketsmentioning

confidence: 99%

Negotiation, Sanctions, and Context Dependency in the Legume-Rhizobium Mutualism

Akçay

Simms

2011

The American Naturalist

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Two important questions about mutualisms are how the fitness costs and benefits to the mutualist partners are determined and how these mechanisms affect the evolutionary dynamics of the mutualism. We tackle these questions with a model of the legumerhizobium symbiosis that regards the mutualism outcome as a result of biochemical negotiations between the plant and its nodules. We explore the fitness consequences of this mechanism to the plant and rhizobia and obtain four main results. First, negotiations permit the plant to differentially reward more-cooperative rhizobia-a phenomenon termed "plant sanctions"-but only when more-cooperative rhizobia also provide the plant with good outside options during negotiations with other nodules. Second, negotiations may result in seemingly paradoxical cases where the plant is worse off when it has a "choice" between two strains of rhizobia than when infected by either strain alone. Third, even when sanctions are effective, they are by themselves not sufficient to maintain cooperative rhizobia in a population: less cooperative strains always have an advantage at the population level. Finally, partner fidelity feedback, together with genetic correlations between a rhizobium strain's cooperativeness and the outside options it provides, can maintain cooperative rhizobia. Our results show how joint control over the outcome of a mutualism through the proximate mechanism of negotiation can affect the evolutionary dynamics of interspecific cooperation. Disciplines Biology | Developmental Biology | Evolution CommentsAt the time of publication, author Erol Akçay was affiliated with the University of Tennessee. Currently, he is a faculty member at the Department of Biology at the University of Pennsylvania. Online enhancements: appendix, Mathematica file.abstract: Two important questions about mutualisms are how the fitness costs and benefits to the mutualist partners are determined and how these mechanisms affect the evolutionary dynamics of the mutualism. We tackle these questions with a model of the legumerhizobium symbiosis that regards the mutualism outcome as a result of biochemical negotiations between the plant and its nodules. We explore the fitness consequences of this mechanism to the plant and rhizobia and obtain four main results. First, negotiations permit the plant to differentially reward more-cooperative rhizobia-a phenomenon termed "plant sanctions"-but only when more-cooperative rhizobia also provide the plant with good outside options during negotiations with other nodules. Second, negotiations may result in seemingly paradoxical cases where the plant is worse off when it has a "choice" between two strains of rhizobia than when infected by either strain alone. Third, even when sanctions are effective, they are by themselves not sufficient to maintain cooperative rhizobia in a population: less cooperative strains always have an advantage at the population level. Finally, partner fidelity feedback, together with genetic correlations between a rhizobium strain...

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Section: Control and Outside Options In Biological Marketsmentioning

confidence: 99%

Negotiation, Sanctions, and Context Dependency in the Legume-Rhizobium Mutualism

Akçay

Simms

2011

The American Naturalist

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“…Como o feijão macassar tem a capacidade de ser nodulado por uma ampla faixa de rizóbios (Rumjanek et al, 2005), é provável que, em muitas situações, as estirpes nativas dos solos nodulem as plantas e formem simbiose eficiente (Silva et al, 2008); no entanto, o desempenho da simbiose quanto à fixação biológica do nitrogênio (FBN) depende da interação entre planta e micro-organismo (Souza et al, 1999;KrasovaWade et al, 2003;Schulze, 2004;Lima et al, 2005;Jemo et al, 2006;Lacerda & Silva, 2006). Pouco se sabe sobre as estirpes nativas dos solos da região, mas já foram identificadas algumas com boa capacidade de FBN, inclusive a oficialmente recomendada para a cultura (Martins et al, 2003).…”

Section: Introductionunclassified

Inoculação de variedades locais de feijão macassar com estirpes selecionadas de rizóbio

Vieira¹,

Freitas

Silva³

et al. 2010

Rev. bras. eng. agríc. ambient.

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RESUMOA combinação eficiente entre variedades e estirpes de rizóbio é importante para aumentar a produtividade do feijão macassar; entretanto, estirpes selecionadas não foram testadas com a maioria das variedades cultivadas na região semiárida do Nordeste do Brasil. Com o objetivo de avaliar a eficiência de quatro estirpes recomendadas de rizóbio em seis variedades de feijão macassar cultivadas no Agreste da Paraíba, conduziu-se um experimento fatorial em blocos casualizados com três repetições, em vasos de Leonard contendo substrato estéril. As variedades IPA 206, Sedinha, Corujinha, Canapu, Sempre Verde e Azul, receberam inoculação com as estirpes BR 3267, BR 2001, EI 6 e NFB 700, além dos tratamentos com e sem fertilização nitrogenada. As plantas foram colhidas 40 dias após o plantio. As estirpes BR 3267 e BR 2001 produziram os melhores resultados quanto a biomassa, teores e conteúdos de N na planta e número de nódulos. A inoculação com a EI 6 resultou em um desempenho fraco, especialmente com a variedade IPA 206. O desempenho da estirpe NFB 700 foi um pouco melhor que o da EI 6. Sedinha e Sempre Verde foram as melhores variedades em produtividade de biomassa, conteúdo de N e número de nódulos. Inoculation of local cowpea varieties with selected rhizobia strains Palavras ABSTRACTThe efficient combination of cowpea variety and rhizobia strain is important to raise crop productivity. However, selected strains have not been tested with most of the varieties cultivated in the semiarid area of Northeast Brazil. To evaluate the efficiency of four recommended strains with six cowpea varieties cultivated in the Agreste region of Paraíba, a completely randomized factorial experiment, with three replications, was conducted in Leonard pots filled with sterilized substrate. Varieties "IPA 206", "Sedinha", "Corujinha", "Canapu", "Sempre Verde" and "Azul" were inoculated with BR 3267, BR 2001, EI 6 and NFB 700 strains, plus two treatments with, and without, N fertilizer. Plants were harvested 40 days after sowing. BR 3267 and BR 2001 strains produced the highest biomass, N concentrations and contents and nodule numbers. Inoculation with EI 6 resulted in poor plant performance, especially with variety IPA 206. Performance with NFB 700 was slightly better than with EI 6. Sedinha and Sempre Verde were the best varieties regarding biomass, N content and nodule numbers.

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“…Rhizobia invade the root nodules and differentiate into bacteroids that fix nitrogen (14,16,21,36,37). Atmospheric dinitrogen converted into ammonia is further transported and assimilated by the plant, which, reciprocally, provides photosynthates (42,43,50). The range of plant benefits varies and depends on the effectiveness of the bacterial strains as well as the legume plant genotype (8).…”

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confidence: 99%

Genetic and Metabolic Divergence within aRhizobium leguminosarumbv.trifoliiPopulation Recovered from Clover Nodules

Wielbo

Marek-Kozaczuk

Mazur

et al. 2010

Appl Environ Microbiol

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Rhizobia are able to establish symbiosis with leguminous plants and usually occupy highly complex soil habitats. The large size and complexity of their genomes are considered advantageous, possibly enhancing their metabolic and adaptive potential and, in consequence, their competitiveness. A population of Rhizobium leguminosarum bv. trifolii organisms recovered from nodules of several clover plants growing in each other's vicinity in the soil was examined regarding possible relationships between their metabolic-physiological properties and their prevalence in such a local population. Genetic and metabolic variability within the R. leguminosarum bv. trifolii strains occupying nodules of several plants was of special interest, and both types were found to be considerable. Moreover, a prevalence of metabolically versatile strains, i.e., those not specializing in utilization of any group of substrates, was observed by combining statistical analyses of Biolog test results with the frequency of occurrence of genetically distinct strains. Metabolic versatility with regard to nutritional requirements was not directly advantageous for effectiveness in the symbiotic interaction with clover: rhizobia with specialized metabolism were more effective in symbiosis but rarely occurred in the population. The significance of genetic and, especially, metabolic complexity of bacteria constituting a nodule population is discussed in the context of strategies employed by bacteria in competition.The soil bacterium Rhizobium leguminosarum bv. trifolii is capable of symbiotic interaction with the host plant Trifolium spp. (clover). The symbiotic process involves an exchange of chemical signals between both organisms, resulting in the expression of specific bacterial and plant genes. In response to flavonoid signals from legumes, bacterial lipochitooligosaccharides (Nod factors) are synthesized and in turn trigger the expression of plant genes and root nodule formation (9). Rhizobia invade the root nodules and differentiate into bacteroids that fix nitrogen (14,16,21,36,37). Atmospheric dinitrogen converted into ammonia is further transported and assimilated by the plant, which, reciprocally, provides photosynthates (42,43,50). The range of plant benefits varies and depends on the effectiveness of the bacterial strains as well as the legume plant genotype (8).A common feature of rhizobial genomes is the complexity and diversity of genomic organization, with a single chromosome and large plasmids ranging in size from ca. 100 kb up to 2 Mb (34). The genes encoding symbiotic functions usually constitute independent replicons known as symbiotic plasmids (pSym), or symbiotic islands when incorporated into the chromosome (25). The plasmids constitute a pool of accessory genetic information (18, 53) and contribute to the plasticity and dynamic state of the genome commonly observed among members of the Rhizobiaceae family (4,25,28,34). Rhizobia occupy highly complex soil habitats, and their large and multipartite genomes, which encode many poten...

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How are nitrogen fixation rates regulated in legumes?

Cited by 137 publications

References 131 publications

Negotiation, Sanctions, and Context Dependency in the Legume-Rhizobium Mutualism

Negotiation, Sanctions, and Context Dependency in the Legume-Rhizobium Mutualism

Inoculação de variedades locais de feijão macassar com estirpes selecionadas de rizóbio

Genetic and Metabolic Divergence within aRhizobium leguminosarumbv.trifoliiPopulation Recovered from Clover Nodules

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