Characterization of native Frankia strains isolated from chilean shrubs (Rhamnaceae)

Car, Margarita

doi:10.1007/bf00038757

Cited by 7 publications

(10 citation statements)

References 31 publications

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“…This semiarid ecosystem is characterized by a Mediterranean climate with dry summers and rainy winters (Gajardo, 1994 ) and by a shrubland plant community of hardleaved plant species and small trees surrounded by grasses (Fuentes et al, 1984 ). Its Andean part is particular in that it is covered with vegetational patches of Colletia hystrix (Clos) a native actinorhizal plant forming a symbiosis with the nitrogen-fixing actinomycete Frankia (Carú, 1993 ; Carú et al, 2003 ). This symbiosis is an important source of nitrogen input into the soil resulting in higher amounts of nitrogen in soil associated to the plants than in the bulk soil (Orlando et al, 2007 ).…”

Section: Introductionmentioning

confidence: 99%

Diversity and Activity of Denitrifiers of Chilean Arid Soil Ecosystems

Orlando¹,

Carú²,

Pommerenke³

et al. 2012

Front. Microbio.

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The Chilean sclerophyllous matorral is a Mediterranean semiarid ecosystem affected by erosion, with low soil fertility, and limited by nitrogen. However, limitation of resources is even more severe for desert soils such as from the Atacama Desert, one of the most extreme arid deserts on Earth. Topsoil organic matter, nitrogen and moisture content were significantly higher in the semiarid soil compared to the desert soil. Although the most significant loss of biologically preferred nitrogen from terrestrial ecosystems occurs via denitrification, virtually nothing is known on the activity and composition of denitrifier communities thriving in arid soils. In this study we explored denitrifier communities from two soils with profoundly distinct edaphic factors. While denitrification activity in the desert soil was below detection limit, the semiarid soil sustained denitrification activity. To elucidate the genetic potential of the soils to sustain denitrification processes we performed community analysis of denitrifiers based on nitrite reductase (nirK and nirS) genes as functional marker genes for this physiological group. Presence of nirK-type denitrifiers in both soils was demonstrated but failure to amplify nirS from the desert soil suggests very low abundance of nirS-type denitrifiers shedding light on the lack of denitrification activity. Phylogenetic analysis showed a very low diversity of nirK with only three distinct genotypes in the desert soil which conditions presumably exert a high selection pressure. While nirK diversity was also limited to only few, albeit distinct genotypes, the semiarid matorral soil showed a surprisingly broad genetic variability of the nirS gene. The Chilean matorral is a shrub land plant community which form vegetational patches stabilizing the soil and increasing its nitrogen and carbon content. These islands of fertility may sustain the development and activity of the overall microbial community and of denitrifiers in particular.

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Section: Introductionmentioning

confidence: 99%

Diversity and Activity of Denitrifiers of Chilean Arid Soil Ecosystems

Orlando¹,

Carú²,

Pommerenke³

et al. 2012

Front. Microbio.

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“…Many nodulated members of the family Rhamnaceae are found only in South America, especially in Chile, and are confined to the semiarid region of central Chile as part of the xerophytic matorral (32). These plants have yielded Frankia strains quite readily, suggesting that different groups of Frankia may predominate in different genera of rhamnaceous plants (7)(8)(9)(10)(11).…”

mentioning

confidence: 99%

“…Six isolates used in this study (ChI5, Ds12B, DtI2, ReI6, TqI15, and TtI1) have been phenotypically characterized and differ in some traits, such as physiology, sporulation qualities, resistance to antibiotics, and others (6,8,9,11). Despite having similar 16S rDNA sequences, strain ReI6 grows well on sucrose, whereas TtI1 grows better with pyruvate than with sucrose (6).…”

mentioning

confidence: 99%

Diversity of Frankia Strains in Root Nodules of Plants from the Families Elaeagnaceae and Rhamnaceae

Clawson

Carú

Benson

1998

Appl Environ Microbiol

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Partial 16S ribosomal DNAs (rDNAs) were PCR amplified and sequenced from Frankia strains living in root nodules of plants belonging to the families Elaeagnaceae and Rhamnaceae, includingColletia hystrix, Elaeagnus angustifolia, an unidentified Elaeagnus sp., Talguenea quinquenervia, and Trevoa trinervis. Nearly full-length 16S rDNAs were sequenced from strains ofFrankia living in nodules of Ceanothus americanus, C. hystrix, Coriaria arborea, and Trevoa trinervis. Partial sequences also were obtained from Frankia strains isolated and cultured from the nodules of C. hystrix, Discaria serratifolia, D. trinervis, Retanilla ephedra, T. quinquenervia, and T. trinervis (Rhamnaceae). Comparison of these sequences and other published sequences ofFrankia 16S rDNA reveals that the microsymbionts and isolated strains from the two plant families form a distinct phylogenetic clade, except for those from C. americanus. All sequences in the clade have a common 2-base deletion compared with other Frankia strains. Sequences from C. americanus nodules lack the deletion and cluster withFrankia strains infecting plants of the family Rosaceae. Published plant phylogenies (based on chloroplast rbcLsequences) group the members of the families Elaeagnaceae and Rhamnaceae together in the same clade. Thus, with the exception ofC. americanus, actinorhizal plants of these families and their Frankia microsymbionts share a common symbiotic origin.

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“…The southern hemisphere actinorhizal tribe Colletieae is nodulated by Cluster 3 Frankia strains. Several strains have been isolated from root nodules of the South American representatives (Caru 1993, Schwencke and Caru 2001), but the ecological diversity patterns are not yet known.…”

Section: Geographical and Ecological Patterns Of Actinorhizal Symbiontsmentioning

confidence: 99%

Recent advances in the biogeography and genecology of symbioticFrankiaand its host plants

Benson

Dawson

2007

Physiologia Plantarum

119

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Molecular phylogenetic approaches have begun to outline the origin, distribution and diversity of actinorhizal partners. Geographic isolation of Frankia and its host plants resulting from shifting continents and dispersal patterns have apparently led to the development of Frankia genotypes with differing affinities for host genera, even within the same plant family. Actinorhizal plant genera of widespread global distribution tend to nodulate readily even outside their native ranges. These taxa may maintain infective Frankia populations of considerable diversity on a broad scale. Arid environments seem to have distinctive actinorhizal partnerships, with smaller and more specific sets of Frankia symbionts. This has led to the hypothesis that some host families have taxa that are evolving towards narrow strain specificity, perhaps because of drier habitats where fewer Frankia strains would be able to survive. Harsh conditions such as water‐saturated soils near lakes, swamps or bogs that are typically acidic and low in oxygen may similarly lessen the diversity of Frankia strains present in the soil, perhaps limiting the pool of frankiae available for infection locally and, at a larger scale, for natural selection of symbiotic partnerships with host plants. Recent molecular ecological studies have also provided examples of Frankia strain sorting by soil environment within higher order cluster groupings of Frankia host specificity. Future frontiers for ecological research on Frankia and actinorhizal plants include the soil ecosystem and the genome of Frankia and its hosts.

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Characterization of native Frankia strains isolated from chilean shrubs (Rhamnaceae)

Cited by 7 publications

References 31 publications

Diversity and Activity of Denitrifiers of Chilean Arid Soil Ecosystems

Diversity and Activity of Denitrifiers of Chilean Arid Soil Ecosystems

Diversity of Frankia Strains in Root Nodules of Plants from the Families Elaeagnaceae and Rhamnaceae

Recent advances in the biogeography and genecology of symbioticFrankiaand its host plants

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