Characterization of RFRS9, a second member of the Rhizobium fredii repetitive sequence family from the nitrogen-fixing symbiont R. fredii USDA257.
AUTOR(ES)
Krishnan, H B
RESUMO
The genome of the nitrogen-fixing symbiont, Rhizobium fredii USDA257, contains nine copies of repetitive sequences known as the R. fredii repetitive sequence (RFRS) family. We previously sequenced RFRS3, which is linked to symbiosis plasmid-borne nodulation genes of this organism and has substantial homology to the T-DNA of Agrobacterium rhizogenes and lesser homology to reiterated sequences of Bradyrhizobium japonicum. Here we characterize a second family member, RFRS9. The EcoRI fragment containing RFRS9 is 1,248 bp in length and contains a single 666-bp open reading frame that is flanked by perfect 8-bp inverted repeats. Nucleic and amino acid sequences corresponding to the C terminus of the putative RFRS9 protein are nearly identical to those of RFRS3, and they retain homology to DNA from A. rhizogenes. The central portion of the RFRS9 protein also appears to be related to the S locus-specific glycoprotein family of pollen stigma incompatibility glycoproteins from Brassica oleracea, which are involved in signal perception. Sequences that define the RFRS family are restricted to the open reading frame of RFRS9 and associated upstream sequences. These regions also contain a second group of repetitive sequences, which is present in four copies within the genome of USDA257. Both families of repetitive sequences are ubiquitous in R. fredii, and they are preferentially localized on symbiosis plasmids. Southern hybridization confirms that sequences homologous to RFRS9 are present in broad-host-range Rhizobium sp. strain NGR234, in A. rhizogenes, and in two biotype 3 strains of Agrobacterium tumefaciens.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=202070Documentos Relacionados
- Characterization of a Mannitol-Utilizing, Nitrogen-Fixing Bradyrhizobium japonicum USDA 110 Derivative †
- The Aquatic Budding Bacterium Blastobacter denitrificans Is a Nitrogen-Fixing Symbiont of Aeschynomene indica
- Genetic structure of natural populations of the nitrogen-fixing bacterium Rhizobium meliloti.
- Release of Flavonoids by the Soybean Cultivars McCall and Peking and Their Perception as Signals by the Nitrogen-Fixing Symbiont Sinorhizobium fredii1
- Characterization of Azospirillum Isolated from Nitrogen-Fixing Roots of Harvested Sorghum Plants