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Frankia

About: Frankia is a research topic. Over the lifetime, 1324 publications have been published within this topic receiving 32888 citations.


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Journal ArticleDOI
TL;DR: A wide diversity of nitrogen-fixing bacterial species belonging to most phyla of the Bacteria domain have the capacity to colonize the rhizosphere and to interact with plants.
Abstract: Nitrogen is generally considered one of the major limiting nutrients in plant growth. The biological process responsible for reduction of molecular nitrogen into ammonia is referred to as nitrogen fixation. A wide diversity of nitrogen-fixing bacterial species belonging to most phyla of the Bacteria domain have the capacity to colonize the rhizosphere and to interact with plants. Leguminous and actinorhizal plants can obtain their nitrogen by association with rhizobia or Frankia via differentiation on their respective host plants of a specialized organ, the root nodule. Other symbiotic associations involve heterocystous cyanobacteria, while increasing numbers of nitrogen-fixing species have been identified as colonizing the root surface and, in some cases, the root interior of a variety of cereal crops and pasture grasses. Basic and advanced aspects of these associations are covered in this review.

631 citations

Journal ArticleDOI
TL;DR: Sufficient information about the relationship of Frankia strains to other bacteria, and to each other, is now available to warrant the creation of some species based on phenotypic and genetic criteria.

528 citations

Journal ArticleDOI
24 Feb 1978-Science
TL;DR: The soil actinomycete causing formation of nitrogen-fixing symbiotic nodules on roots of the woody angiosperm Comptonia peregrina (L.) Coult has been isolated from surface-sterilized root nodules after incubation and enzyme maceration.
Abstract: The soil actinomycete causing formation of nitrogen-fixing symbiotic nodules on roots of the woody angiosperm Comptonia peregrina (L.) Coult. (Myricaceae) has been isolated from surface-sterilized root nodules after incubation and enzyme maceration. The filamentous bacterium grows slowly in pure culture on a yeast extract medium, producing sporogenous bodies which form large numbers of ovoid spores. Reinfection of sand-grown or aeroponically grown seedlings of Comptonia was achieved repeatedly with inocula prepared from suspensions of the Comptonia isolate. The same actinomycete has been reisolated from these seedling nodules. The induced nodules are highly active in the acetylene-reduction assay, and plants grow vigorously without an exogenous supply of fixed nitrogen.

394 citations

Journal ArticleDOI
TL;DR: Analysis of symbiotic mutants of host plants and bacterial microsymbionts has revealed that present-day endosymbioses require the coordinated induction of more than one signalling pathway for development.

354 citations

Journal ArticleDOI
TL;DR: The results support the idea that major genome expansions as well as reductions can occur in facultative symbiotic soil bacteria as they respond to new environments in the context of their symbioses.
Abstract: Soil bacteria that also form mutualistic symbioses in plants encounter two major levels of selection. One occurs during adaptation to and survival in soil, and the other occurs in concert with host plant speciation and adaptation. Actinobacteria from the genus Frankia are facultative symbionts that form N2-fixing root nodules on diverse and globally distributed angiosperms in the "actinorhizal" symbioses. Three closely related clades of Frankia sp. strains are recognized; members of each clade infect a subset of plants from among eight angiosperm families. We sequenced the genomes from three strains; their sizes varied from 5.43 Mbp for a narrow host range strain (Frankia sp. strain HFPCcI3) to 7.50 Mbp for a medium host range strain (Frankia alni strain ACN14a) to 9.04 Mbp for a broad host range strain (Frankia sp. strain EAN1pec.) This size divergence is the largest yet reported for such closely related soil bacteria (97.8%–98.9% identity of 16S rRNA genes). The extent of gene deletion, duplication, and acquisition is in concert with the biogeographic history of the symbioses and host plant speciation. Host plant isolation favored genome contraction, whereas host plant diversification favored genome expansion. The results support the idea that major genome expansions as well as reductions can occur in facultative symbiotic soil bacteria as they respond to new environments in the context of their symbioses.

350 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202318
202257
202112
202028
201924
201826