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Hokkaido University Collection of Scholarly and Academic Papers >
Graduate School of Agriculture / Faculty of Agriculture >
Peer-reviewed Journal Articles, etc >
Stringent Expression Control of Pathogenic R-body Production in Legume Symbiont Azorhizobium caulinodans
| Title: | Stringent Expression Control of Pathogenic R-body Production in Legume Symbiont Azorhizobium caulinodans |
| Authors: | Matsuoka, Jun-ichi Browse this author | | Ishizuna, Fumiko Browse this author | | Kurumisawa, Keigo Browse this author | | Morohashi, Kengo Browse this author | | Ogawa, Tetsuhiro Browse this author | | Hidaka, Makoto Browse this author | | Saito, Katsuharu Browse this author | | Ezawa, Tatsuhiro Browse this author →KAKEN DB | | Aono, Toshihiro Browse this author |
| Keywords: | R body | | legume | | pathogenesis | | reb gene | | rhizobia | | symbiosis |
| Issue Date: | 2017 |
| Publisher: | American Society for Microbiology |
| Journal Title: | mBio |
| Volume: | 8 |
| Issue: | 4 |
| Publisher DOI: | 10.1128/mBio.00715-17 |
| Abstract: | R bodies are insoluble large polymers consisting of small proteins encoded by reb genes and are coiled into cylindrical structures in bacterial cells. They were first discovered in Caedibacter species, which are obligate endosymbionts of paramecia. Caedibacter confers a killer trait on the host paramecia. R-body-producing symbionts are released from their host paramecia and kill symbiont-free paramecia after ingestion. The roles of R bodies have not been explained in bacteria other than Caedibacter. Azorhizobium caulinodans ORS571, a microsymbiont of the legume Sesbania rostrata, carries a reb operon containing four reb genes that are regulated by the repressor PraR. Herein, deletion of the praR gene resulted in R-body formation and death of host plant cells. The rebR gene in the reb operon encodes an activator. Three PraR binding sites and a RebR binding site are present in the promoter region of the reb operon. Expression analyses using strains with mutations within the PraR binding site and/or the RebR binding site revealed that PraR and RebR directly control the expression of the reb operon and that PraR dominantly represses reb expression. Furthermore, we found that the reb operon is highly expressed at low temperatures and that 2-oxoglutarate induces the expression of the reb operon by inhibiting PraR binding to the reb promoter. We conclude that R bodies are toxic not only in paramecium symbiosis but also in relationships between other bacteria and eukaryotic cells and that R-body formation is controlled by environmental factors. |
| Type: | article |
| URI: | http://hdl.handle.net/2115/88329 |
| Appears in Collections: | 農学院・農学研究院 (Graduate School of Agriculture / Faculty of Agriculture) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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