ABSTRACT
This paper presents the first in-depth research on the biological and genomic properties of lytic rhizobiophage AP-J-162 isolated from the soils of the mountainous region of Dagestan (North Caucasus), which belongs to the centers of origin of cultivated plants, according to Vavilov N.I. The rhizobiophage host strains are nitrogen-fixing bacteria of the genus Sinorhizobium spp., symbionts of leguminous forage grasses. The phage particles have a myovirus virion structure. The genome of rhizobiophage AP-J-162 is double-stranded DNA of 471.5 kb in length; 711 ORFs are annotated and 41 types of tRNAs are detected. The closest phylogenetic relative of phage AP-J-162 is Agrobacterium phage Atu-ph07, but no rhizobiophages are known. The replicative machinery, capsid, and baseplate proteins of phage AP-J-162 are structurally similar to those of Escherichia phage T4, but there is no similarity between their tail protein subunits. Amino acid sequence analysis shows that 339 of the ORFs encode hypothetical or functionally relevant products, while the remaining 304 ORFs are unique. Additionally, 153 ORFs are similar to those of Atu_ph07, with one-third of the ORFs encoding different enzymes. The biological properties and genomic characteristics of phage AP-J-162 distinguish it as a unique model for exploring phage-microbe interactions with nitrogen-fixing symbiotic microorganisms.
Subject(s)
Bacteriophages , Genome, Viral , Phylogeny , Sinorhizobium , Soil Microbiology , Bacteriophages/genetics , Bacteriophages/isolation & purification , Bacteriophages/classification , Bacteriophages/physiology , Sinorhizobium/genetics , Sinorhizobium/virology , Sinorhizobium/physiology , Open Reading FramesABSTRACT
Sinorhizobium meliloti is a symbiotic bacterial species forming nitrogen-fixing nodules on roots of annual and perennial Medicago spp. We report the full genome sequence of S. meliloti strain AK76, an effective symbiont of the wild diploid plant Medicago lupulina grown in the Mugodgary Mountain region, Kazakhstan.
ABSTRACT
Sinorhizobium meliloti is a Gram-negative bacterium which fixes atmospheric nitrogen in symbiosis with Medicago spp. We report the draft genome sequence of S. meliloti strain CXM1-105, associated with nodules of Medicago sativa subsp. varia (Martyn) Arcang.
ABSTRACT
Sinorhizobium meliloti and Sinorhizobium medicae are two closely related species of the genus Sinorhizobium showing a similar host range, nodulating leguminous species of the genera Medicago, Melilotus and Trigonella, but their phylogenic relationship has not been elucidated yet. In this paper we report the application of three different molecular markers, (i) RFLP of nodD genes, (ii) 16S-23S rDNA intergenic gene spacer fingerprinting and (iii) amplification fragment length polymorphism to S. meliloti and S. medicae strains isolated from the Caucasian area, which is the region of origin of the host plant Medicago. The analysis of data could suggest the origin of S. medicae strains from an ancestral S. meliloti population.
Subject(s)
Sinorhizobium meliloti/genetics , Sinorhizobium/genetics , DNA Fingerprinting/methods , Evolution, Molecular , Phylogeny , Plant Roots/microbiology , Polymerase Chain Reaction/methods , Polymorphism, Restriction Fragment Length , RNA, Ribosomal, 16S/analysis , RNA, Ribosomal, 23S/analysis , Random Amplified Polymorphic DNA Technique/methods , Russia , Sinorhizobium/classification , Sinorhizobium/isolation & purification , Sinorhizobium meliloti/isolation & purification , Soil MicrobiologyABSTRACT
Sinorhizobium meliloti was isolated from nodules and soil from western Tajikistan, a center of diversity of the host plants (Medicago, Melilotus, and Trigonella species). There was evidence of recombination, but significant disequilibrium, between and within the chromosome and megaplasmids. The most frequent alleles matched those in the published genome sequence.