著者

Teerana Greetatorn Shun Hashimoto Taro Maeda Mitsutaka Fukudome Pongdet Piromyou Kamonluck Teamtisong Panlada Tittabutr Nantakorn Boonkerd Masayoshi Kawaguchi Toshiki Uchiumi Neung Teaumroong

出版者

Japanese Society of Microbial Ecology / Japanese Society of Soil Microbiology / Taiwan Society of Microbial Ecology / Japanese Society of Plant Microbe Interactions / Japanese Society for Extremophiles

雑誌

Microbes and Environments (ISSN:13426311)

巻号頁・発行日

vol.35, no.3, pp.ME20049, 2020 (Released:2020-07-29)

参考文献数

62

被引用文献数

3

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Bradyrhizobium sp. strain SUTN9-2 is a symbiotic and endophytic diazotrophic bacterium found in legume and rice plants and has the potential to promote growth. The present results revealed that SUTN9-2 underwent cell enlargement, increased its DNA content, and efficiently performed nitrogen fixation in response to rice extract. Some factors in rice extract induced the expression of cell cycle and nitrogen fixation genes. According to differentially expressed genes (DEGs) from the transcriptomic analysis, SUTN9-2 was affected by rice extract and the deletion of the bclA gene. The up-regulated DEGs encoding a class of oxidoreductases, which act with oxygen atoms and may have a role in controlling oxygen at an appropriate level for nitrogenase activity, followed by GroESL chaperonins are required for the function of nitrogenase. These results indicate that following its exposure to rice extract, nitrogen fixation by SUTN9-2 is induced by the collective effects of GroESL and oxidoreductases. The expression of the sensitivity to antimicrobial peptides transporter (sapDF) was also up-regulated, resulting in cell differentiation, even when bclA (sapDF) was mutated. This result implies similarities in the production of defensin-like antimicrobial peptides (DEFs) by rice and nodule-specific cysteine-rich (NCR) peptides in legume plants, which affect bacterial cell differentiation.

著者

Nahoko Uchi Mitsutaka Fukudome Narumi Nozaki Miyuzu Suzuki Ken-ichi Osuki Shuji Shigenobu Toshiki Uchiumi

出版者

Japanese Society of Microbial Ecology · The Japanese Society of Soil Microbiology

雑誌

Microbes and Environments (ISSN:13426311)

巻号頁・発行日

vol.34, no.2, pp.155-160, 2019 (Released:2019-06-27)

参考文献数

37

被引用文献数

18

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Aphids have a mutualistic relationship with the bacterial endosymbiont Buchnera aphidicola. We previously reported seven cysteine-rich peptides in the pea aphid Acyrthosiphon pisum and named them Bacteriocyte-specific Cysteine-Rich (BCR) peptides; these peptides are exclusively expressed in bacteriocytes, special aphid cells that harbor symbionts. Similar symbiotic organ-specific cysteine-rich peptides identified in the root nodules of leguminous plants are named Nodule-specific Cysteine-Rich (NCR) peptides. NCR peptides target rhizobia in the nodules and are essential for symbiotic nitrogen fixation. A BacA (membrane protein) mutant of Sinorhizobium is sensitive to NCR peptides and is unable to establish symbiosis. Based on the structural and expressional similarities between BCR peptides and NCR peptides, we hypothesized that aphid BCR peptides exhibit antimicrobial activity, similar to some NCR peptides. We herein synthesized BCR peptides and investigated their antimicrobial activities and effects on the bacterial membrane of Escherichia coli. The peptides BCR1, BCR3, BCR5, and BCR8 exhibited antimicrobial activities with increased membrane permeability. An sbmA mutant of E. coli, a homolog of bacA of S. meliloti, was more sensitive to BCR peptides than the wild type. Our results suggest that BCR peptides have properties that may be required to control the endosymbiont, similar to NCR peptides in legumes.