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Research Article

Gordonia rhizosphera sp. nov. isolated from the mangrove rhizosphere

Takeuchi, Mariko, Hatano, Kazunori

International Journal of Systematic and Evolutionary Microbiology 1998; 48(3):907 · https://doi.org/10.1099/00207713-48-3-907

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Summary auto-generated

This study describes the isolation and characterization of a novel bacterial species, Gordonia rhizosphera sp. nov., from the mangrove rhizosphere in Japan. Strain 141T was isolated from soil and fine root surfaces of Bruguiera gymnorrhiza in the Shiira River estuary. The bacterium possesses characteristic features of the genus Gordonia, including cell wall chemotype IV with meso-diaminopimelic acid, arabinose, and galactose; MK-9(H2) as the predominant menaquinone; and mycolic acids with 56-64 carbon atoms. DNA analysis revealed a G+C content of 66.8 mol%. The organism is a Gram-positive, non-motile rod forming pink-to-orange colonies, utilizing β-alanine, citrate, and gluconate as carbon sources. Phylogenetic analysis of 16S rRNA sequences showed strain 141T forms a distinct lineage within Gordonia, with closest similarity to G. bronchialis at 99.2%. DNA-DNA hybridization values of 29-31% with G. bronchialis and 7-29% with other Gordonia species confirmed its status as a new species. This represents the first report of Gordonia species isolated from mangrove rhizospheres, which are characterized by muddy, anoxic conditions and higher salinity than terrestrial soils.

Key findings

  • A novel Gordonia species, G. rhizosphera, was isolated from mangrove rhizosphere soil and root surfaces in Okinawa, Japan
  • The strain possesses characteristic Gordonia chemotaxonomic markers including wall chemotype IV, MK-9(H2) menaquinone, and mycolic acids of 56-64 carbon atoms
  • 16S rRNA phylogenetic analysis shows G. rhizosphera as a distinct lineage within Gordonia, most closely related to G. bronchialis at 99.2% sequence similarity
  • DNA-DNA hybridization values of 29-31% with G. bronchialis and 7-29% with other Gordonia species confirm its status as a new species
  • This is the first report of Gordonia species isolated from mangrove rhizosphere environments

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Abstract

The taxonomic position of bacterial strain 141T, isolated from the mangrove rhizosphere, has been clarified by phenotypic, chemotaxonomic and phylogenetic studies. The strain possesses wall chemotype IV, MK-9(H2) as the predominant menaquinone, relatively long-chain mycolic acids (56–64 carbon atoms) and straight-chain saturated and monounsaturated fatty acids with a small amount of tuberculostearic acid. The G+C content of the DNA is 66.8 mol%. Similarity values for genes encoding 16S rRNA indicated that strain 141Trepresents a new species within the genus Gordonia for which the name Gordonia rhizosphera sp. nov. is proposed. The type strain of G. rhizosphera is 141T(= IFO 16068T).