Competition for nodule occupancy between introduced and native strains of Rhizobium leguminosarum biovar trifolii

Blanco, Andrea Rodríguez; Sicardi, Margarita; Frioni, L.

doi:10.1007/s00374-010-0439-y

Cited by 26 publications

(11 citation statements)

References 41 publications

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“…The two sites selected for the field experiments belong to the agroecological zones where a decrease of forage production had been detected after the first year of clover sowing (Rodríguez et al, 2010). They also represent two of the main uses of white clover in Uruguay, at Palo a Pique to improve natural grasslands and at Glencoe as a no-till culture.…”

Section: Resultsmentioning

confidence: 99%

“…trifolii strains without appropriate symbiotic efficiency. These less efficient indigenous rhizobia strains can be more competitive than the inoculant and occupy a significant portion of the nodules, reducing the impact of the inoculant strain on herbage production (Rodríguez et al, 2010; Yates et al, 2011). The commercial inoculant for white clover, as those used in Uruguay for lotus ( Lotus corniculatus L.) and alfalfa ( Medicago sativa L.), were selected decades ago (Lindström et al, 2010), for soil and management conditions different from the current ones.…”

Section: Introductionmentioning

confidence: 99%

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Selection of Competitive and Efficient Rhizobia Strains for White Clover

et al. 2019

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The practice of inoculating forage legumes with rhizobia strains is widespread. It is assumed that the inoculated strain determines the performance of the symbiosis and nitrogen fixation rates. However, native-naturalized strains can be competitive, and actual nodule occupancy is often scarcely investigated. In consequence, failures in establishment, and low productivity attributed to poor performance of the inoculant may merely reflect the absence of the inoculated strain in the nodules. This study lays out a strategy followed for selecting a Rhizobium leguminosarum sv. trifolii strain for white clover ( Trifolium repens ) with competitive nodule occupancy. First, the competitiveness of native-naturalized rhizobia strains selected for their efficiency to fix N 2 in clover and tagged with gus A was evaluated in controlled conditions with different soils. Second, three of these experimental strains with superior nodule occupancy plus the currently recommended commercial inoculant, an introduced strain, were tested in the field in 2 years and at two sites. Plant establishment, herbage productivity, fixation of atmospheric N 2 ( 15 N natural abundance), and nodule occupancy (ERIC-PCR genomic fingerprinting) were measured. In both years and sites, nodule occupancy of the native-naturalized experimental strains was either higher or similar to that of the commercial inoculant in both primary and secondary roots. The difference was even greater in stolon roots nodules, where nodule occupancy of the native-naturalized experimental strains was at least five times greater. The amount of N fixed per unit plant mass was consistently higher with native-naturalized experimental strains, although the proportion of N derived from atmospheric fixation was similar for all strains. Plant establishment and herbage production, as well as clover contribution in oversown native grasslands, were either similar or higher in white clover inoculated with the native-naturalized experimental strains. These results support the use of our implemented strategy for developing a competitive inoculant from native-naturalized strains.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Selection of Competitive and Efficient Rhizobia Strains for White Clover

et al. 2019

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“…Recent studies have shown that native rhizobia can compete for nodule occupancy with nodulating nitrogen-fixing Rhizobium inoculants (diCenzo et al, 2019;Irisarri et al, 2019). Some studies have even suggested that native rhizobia that do not have the appropriate symbiotic efficiency for nitrogen fixation, can be more competitive than nitrogen fixing rhizobia to occupy an important portion of the nodules (Blanco et al, 2010;Yates et al, 2011). In our study, we suggest that in the rhizosphere of T. repens competition between nitrogen-fixing rhizobia and non-nitrogen fixing rhizobia might be affected during increasing intraspecific plant competition.…”

Section: Effects Of Intraspecific Competitionmentioning

confidence: 99%

Effects of Intra- and Interspecific Plant Density on Rhizosphere Bacterial Communities

et al. 2020

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There have been very few studies on the effects of plant competition on the rhizosphere bacterial community. To investigate the impacts of intra-and interspecific plant competition, we analyzed the responses of rhizosphere bacterial communities to plant density as determined by 16S rRNA gene targeted sequencing. We included five weedy plant species growing in field soil in monocultures and mixed cultures at three densities in a greenhouse experiment. The rhizosphere bacterial community of each species changed more with density in a mixture of all five plant species than in monocultures, so intra-and interspecific plant competition had different effects on the bacterial community. For the dominant plant competitor, Centaurea cyanus, neither intra-nor interspecific competition had major effects on the composition of its rhizosphere bacterial communities. In contrast, the bacterial communities of the weakest competitor, Trifolium repens, were affected differently by intra-and interspecific competition. During increasing intraspecific competition T. repens maintained a highly specialized bacterial community dominated by Rhizobium; while during interspecific competition, the relative abundance of Rhizobium declined while other nitrogen fixing and potentially plant growth promoting taxa became more abundant. Contrary to previous observations made for soil microbial communities, the bacterial rhizosphere community of the weakest competitor did not become more similar to that of the dominant species. Thus, the process of competition, as well as the plant species themselves, determined the rhizosphere bacterial community. Our results emphasize the role of plant-plant interactions for rhizosphere bacterial communities. These effects may feedback to affect plant-plant interactions, and this is an important hypothesis for future research.

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“…It is also interesting that this selected inoculum produces antimicrobial activity against indigenous common bean rhizobia. Studies of competition between introduced and native R. leguminosarum strains have been performed for nodulation of T. repens and Trifolium pratense in Uruguay (Blanco et al 2010). Interestingly, pre-treatment of red clover seeds with specific Nod factors significantly enhanced clover nodulation by an inoculant strain and the subsequent growth of plants in the soil (Maj et al 2009).…”

Section: Selection Of Rhizobial Inoculants That Nodulate Legumes In Smentioning

confidence: 97%

Legumes in the reclamation of marginal soils, from cultivar and inoculant selection to transgenic approaches

Peña¹,

Pueyo²

2011

Agron. Sustain. Dev.

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Mineral nitrogen deficiency is a frequent characteristic of arid and semi-arid soils. Biological nitrogen fixation by legumes is a sustainable and environmentalfriendly alternative to chemical fertilization. Therefore, legumes have a high potential for the reclamation of marginal soils. Such issue is becoming more urgent due to the ever-rising requirement for food and feed, and the increasing extension of salinized and degraded lands, both as a consequence of global change and irrigation practices. This manuscript reviews current research on physiological and molecular mechanisms involved in the response and tolerance to environmental stresses of the Rhizobiumlegume symbiosis. We report in particular recent advances on the isolation, characterization, and selection of tolerant rhizobial strains and legume varieties, both by traditional methods and through biotechnological approaches. The major points are the following. (1) Understanding mechanisms involved in stress tolerance is advancing fast, thus providing a solid basis for the selection and engineering of rhizobia and legumes with enhanced tolerance to environmental constraints. (2) The considerable efforts to select locally adapted legume varieties and rhizobial inocula that can fix nitrogen under conditions of drought or salinity are generating competitive crop yields in affected soils. (3) Biotechnological approaches are used to obtain improved legumes and rhizobia with enhanced tolerance to abiotic stresses, paying particular attention to the sensitive nitrogen-fixing activity. Those biotechnologies are yielding transgenic crops and inocula with unquestionable potential.In conclusion, the role of legumes in sustainable agriculture, and particularly, their use in the reclamation of marginal lands, certainly has a very promising future.

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Competition for nodule occupancy between introduced and native strains of Rhizobium leguminosarum biovar trifolii

Cited by 26 publications

References 41 publications

Selection of Competitive and Efficient Rhizobia Strains for White Clover

Selection of Competitive and Efficient Rhizobia Strains for White Clover

Effects of Intra- and Interspecific Plant Density on Rhizosphere Bacterial Communities

Legumes in the reclamation of marginal soils, from cultivar and inoculant selection to transgenic approaches

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