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Data on the spread of intracellular bacteria in oribatid mites (Acari: Oribatida) are scarce. Our work fills a gap in the research on endosymbionts in this group of invertebrates and provides information on Wolbachia infection in Hypochthonius rufulus (Acari: Oribatida) from soil, litter and moss sample collected in south-eastern Poland. This is the first report of Wolbachia in H. rufulus. Phylogeny based on the analysis of the 16S rRNA, gatB , fbpA , gltA , ftsZ and hcpA gene sequences revealed that Wolbachia from H. rufulus represented supergroup E and was related to bacterial endosymbionts of Collembola. The unique sequence within Wolbachia supergroup E was detected for the 16S rRNA gene of the bacteria from H. rufulus. The sequences of Wolbachia 16S rRNA and housekeeping genes have been deposited in publicly available databases and are an important source of molecular data for comparative studies. [Display omitted] • This is the first report of Wolbachia in Hypochthonius rufulus (Acari: Oribatida). • Phylogeny revealed that Wolbachia from H. rufulus clustered with bacteria of supergroup E. • 5'-GGGGTAATGGCC-3′ in 16S rDNA of supergroup E was in Wolbachia from H. rufulus. [ABSTRACT FROM AUTHOR]

In this study, the diversity and the phylogenetic relationships of bacteria isolated from root nodules of Chamaecytisus ruthenicus growing in Poland were investigated using ERIC-PCR fingerprinting and by multilocus sequence analysis (MLSA). Two major clusters comprising 13 and 3 isolates were detected which 16S rRNA gene sequencing identified as Bradyrhizobium and Phyllobacterium. The results of phylogenetic analysis of individual and concatenated atpD , gyrB and recA gene sequences showed that the studied strains may represent novel species in the genera Bradyrhizobium and Phyllobacterium. In the phylogenetic tree based on the atpD-gyrB-recA concatemers, Bradyrhizobium isolates were split into two groups closely related to Bradyrhizobium algeriense STM89T and Bradyrhizobium valentinum LmjM3T. The genus Phyllobacterium isolates formed a separate cluster close to Phyllobacterium ifriqiyense LMG27887T in the atpD-gyrB-recA phylogram. Analysis of symbiotic gene sequences (nodC , nodZ , nifD , and nifH) showed that the Bradyrhizobium isolates were most closely related to Bradyrhizobium algeriense STM89T, Bradyrhizobium valentinum LmjM3T and Bradyrhizobium retamae Ro19T belonging to symbiovar retamae. This is the first report on the occurrence of members of symbiovar retamae from outside the Mediterranean region. No symbiosis related genes were amplified from Phyllobacterium strains, which were also unable to induce nodules on C. ruthenicus roots. Based on these findings Phyllobacterium isolates can be regarded as endophytic bacteria inhabitating root nodules of C. ruthenicus. [ABSTRACT FROM AUTHOR]

A collection of 18 previously unstudied strains isolated from root nodules of Genista germanica (German greenweed) grown in southeast Poland was evaluated for the level of genetic diversity using the BOX-PCR technique and the phylogenetic relationship based on both core (16S rRNA, dnaK , ftsA , glnII , gyrB , recA , rpoB) and nodulation (nodC and nodZ) gene sequences. Each of the 18 G. germanica root nodule isolates displayed unique BOX-PCR patterns, indicating their high level of genomic heterogeneity. Based on the comparative 16S rDNA sequence analysis, 12 isolates were affiliated to the Bradyrhizobium genus and the other strains were most similar to Rhizobium species. Phylogenetic analysis of the core gene sequences indicated that the studied Bradyrhizobium bacteria were most closely related to Bradyrhizobium japonicum , whereas Rhizobium isolates were most closely related to Rhizobium lusitanum and R. leguminosarum. The phylogenies of nodC and nodZ for the Rhizobium strains were incongruent with each other and with the phylogenies inferred from the core gene sequences. All Rhizobium nodZ gene sequences acquired in this study were grouped with the sequences of Bradyrhizobium strains. Some of the studied Rhizobium isolates were placed in the nodC phylogenetic tree together with reference Rhizobium species, while the others were closely related to Bradyrhizobium bacteria. The results provided evidence for horizontal transfer of nodulation genes between Bradyrhizobium and Rhizobium. However, the horizontal transfer of nod genes was not sufficient for Rhizobium strains to form nodules on G. germanica roots, suggesting that symbiotic genes have to be adapted to the bacterial genome. [ABSTRACT FROM AUTHOR]