English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Zendy Plus

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Zendy Tools

Zendy Open

Background  Rhizobia are soil bacteria that establish symbiotic relationships with legumes and fix nitrogen in root nodules. We recently reported that several nitrogen-fixing rhizobial strains, belonging to  Rhizobium phaseoli, R. trifolii, R. grahamii  and  Sinorhizobium americanum,  were able to colonize  Phaseolus vulgaris  (common bean) seeds. To gain further insight into the traits that support this ability, we analyzed the genomic sequences and proteomes of  R. phaseoli  (CCGM1) and  S. americanum  (CCGM7) strains from seeds and compared them with those of the closely related strains CIAT652 and CFNEI73, respectively, isolated only from nodules.    Results  In a fine structural study of the  S. americanum  genomes, the chromosomes, megaplasmids and symbiotic plasmids were highly conserved and syntenic, with the exception of the smaller plasmid, which appeared unrelated. The symbiotic tract of CCGM7 appeared more disperse, possibly due to the action of transposases. The chromosomes of seed strains had less transposases and strain-specific genes. The seed strains CCGM1 and CCGM7 shared about half of their genomes with their closest strains (3353 and 3472 orthologs respectively), but a large fraction of the rest also had homology with other rhizobia. They contained 315 and 204 strain-specific genes, respectively, particularly abundant in the functions of transcription, motility, energy generation and cofactor biosynthesis. The proteomes of seed and nodule strains were obtained and showed a particular profile for each of the strains. About 82 % of the proteins in the comparisons appeared similar. Forty of the most abundant proteins in each strain were identified; these proteins in seed strains were involved in stress responses and coenzyme and cofactor biosynthesis and in the nodule strains mainly in central processes. Only 3 % of the abundant proteins had hypothetical functions.    Conclusions  Functions that were enriched in the genomes and proteomes of seed strains possibly participate in the successful occupancy of the new niche. The genome of the strains had features possibly related to their presence in the seeds. This study helps to understand traits of rhizobia involved in seed adaptation.    Electronic supplementary material  The online version of this article (doi:10.1186/s12864-016-3053-z) contains supplementary material, which is available to authorized users.

Genomic studies of nitrogen-fixing rhizobial strains from Phaseolus vulgaris seeds and nodules