Language：English   Publishing type：Research paper (scientific journal)   Publisher：{MDPI} {AG}  

DOI： 10.3390/plants10020381

Scopus

PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Society of Microbial Ecology  

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.

DOI： https://doi.org/10.1264/jsme2.me20049

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：{MDPI} {AG}  

Reactive sulfur species (RSS) function as strong antioxidants and are involved in various biological responses in animals and bacteria. Few studies; however, have examined RSS in plants. In the present study, we clarified that RSS are involved in root nodule symbiosis in the model legume Lotus japonicus. Polysulfides, a type of RSS, were detected in the roots by using a sulfane sulfur-specific fluorescent probe, SSP4. Supplying the sulfane sulfur donor Na2S3 to the roots increased the amounts of both polysulfides and hydrogen sulfide (H2S) in the roots and simultaneously decreased the amounts of nitric oxide (NO) and reactive oxygen species (ROS). RSS were also detected in infection threads in the root hairs and in infected cells of nodules. Supplying the sulfane sulfur donor significantly increased the numbers of infection threads and nodules. When nodules were immersed in the sulfane sulfur donor, their nitrogenase activity was significantly reduced, without significant changes in the amounts of NO, ROS, and H2S. These results suggest that polysulfides interact with signal molecules such as NO, ROS, and H2S in root nodule symbiosis in L. japonicus. SSP4 and Na2S3 are useful tools for study of RSS in plants.

DOI： https://doi.org/10.3390/antiox9020145

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：{MDPI} {AG}  

Flooding limits biomass production in agriculture. Leguminous plants, important agricultural crops, use atmospheric dinitrogen gas as nitrogen nutrition by symbiotic nitrogen fixation with rhizobia, but this root-nodule symbiosis is sometimes broken down by flooding of the root system. In this study, we analyzed the effect of flooding on the symbiotic system of transgenic Lotus japonicus lines which overexpressed class 1 phytoglobin (Glb1) of L. japonicus (LjGlb1-1) or ectopically expressed that of Alnus firma (AfGlb1). In the roots of wild-type plants, flooding increased nitric oxide (NO) level and expression of senescence-related genes and decreased nitrogenase activity; in the roots of transgenic lines, these effects were absent or less pronounced. The decrease of chlorophyll content in leaves and the increase of reactive oxygen species (ROS) in roots and leaves caused by flooding were also suppressed in these lines. These results suggest that increased levels of Glb1 help maintain nodule symbiosis under flooding by scavenging NO and controlling ROS.

DOI： 10.3390/antiox8070206

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Society of Microbial Ecology  

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.

DOI： 10.1264/jsme2.me18148

Event date： 2024.1

Language：English   Presentation type：Poster presentation  

Event date： 2023.12

Language：English   Presentation type：Poster presentation  

Venue：かがわ国際会議場   Country：Japan  

Event date： 2023.12

Language：English   Presentation type：Poster presentation  

Venue：かがわ国際会議場  

Event date： 2023.12

Language：English   Presentation type：Poster presentation  

Venue：かがわ国際会議場   Country：Japan  

Event date： 2023.12

Language：English   Presentation type：Poster presentation  

Venue：かがわ国際会議場   Country：Japan  

Event date： 2023.12

Language：English   Presentation type：Poster presentation  

Venue：かがわ国際会議場   Country：Japan  

Event date： 2023.12 - 2023

Language：English   Presentation type：Oral presentation (general)  

Venue：かがわ国際会議場   Country：Japan  

Event date： 2023.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：大阪公立大学（中百舌鳥キャンパス）   Country：Japan  

Event date： 2023.3

Language：Japanese   Presentation type：Poster presentation  

Event date： 2023.3

Language：Japanese   Presentation type：Poster presentation  

Event date： 2023.1

Language：English   Presentation type：Poster presentation  

Event date： 2023.1

Language：English   Presentation type：Poster presentation  

Event date： 2023.1

Language：English   Presentation type：Poster presentation  

Event date： 2022.10

Language：English   Presentation type：Oral presentation (invited, special)  

Event date： 2022.9

Language：Japanese   Presentation type：Oral presentation (general)  

Event date： 2022.6

Language：Japanese   Presentation type：Oral presentation (general)  

Event date： 2022.6

Language：Japanese   Presentation type：Oral presentation (general)  

Event date： 2022.5

Language：Japanese   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Event date： 2021.12

Language：Japanese   Presentation type：Oral presentation (general)  

Event date： 2021.11 - 2021.12

Language：Japanese   Presentation type：Poster presentation  

Event date： 2021.6

Language：Japanese   Presentation type：Oral presentation (general)  

Event date： 2021.3

Language：English   Presentation type：Oral presentation (general)  

Language：Japanese  

DOI： 10.14829/jcsproc.258.0_83