記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Plants  

Under water deficit conditions, the essential macronutrient nitrogen becomes limited as a result of reduced dissolved nitrogen and root nitrogen uptake. An elevated nitrogen level might be able to mitigate these effects, integrated with the idea of using nitric oxide as abiotic stress tolerant inducers. In this study, we evaluated the potential of using elevated nitrogen priming prior to water shortage to mitigate plant stress through nitric oxide accumulation. We grew rice plants in 300 mg L−1 nitrogen for 10 weeks, then we primed plants with four different nitrogen concentrations: 100, 300 (control), 500 and 1000 mg L−1 nitrogen prior to inducing water deficit conditions. Plants primed with 500 mg L−1 nitrogen possessed a higher photosynthetic rate, relative water content, electrolyte leakage and lipid peroxidation under water deficit conditions, compared to control plants. The induction of water deficit tolerance was supported with the activation of antioxidant defense system, induced by the accumulation of nitric oxide in leaves and roots of rice plants. We originally demonstrated the accumulation of nitric oxide in leaves of rice plants. The elevated nitrogen priming can be used to enhance water deficit tolerance in irrigated paddy fields, instead of nitric oxide donors.

DOI： 10.3390/plants10020381

Scopus

PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

記述言語：英語   掲載種別：研究論文（学術雑誌）  

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

開催年月日： 2024年1月

記述言語：英語   会議種別：ポスター発表  

開催年月日： 2023年12月

記述言語：英語   会議種別：ポスター発表  

開催地：かがわ国際会議場   国名：日本国  

開催年月日： 2023年12月

記述言語：英語   会議種別：ポスター発表  

開催地：かがわ国際会議場  

開催年月日： 2023年12月

記述言語：英語   会議種別：ポスター発表  

開催地：かがわ国際会議場   国名：日本国  

開催年月日： 2023年12月

記述言語：英語   会議種別：ポスター発表  

開催地：かがわ国際会議場   国名：日本国  

開催年月日： 2023年12月

記述言語：英語   会議種別：ポスター発表  

開催地：かがわ国際会議場   国名：日本国  

開催年月日： 2023年12月 - 2023年

記述言語：英語   会議種別：口頭発表（一般）  

開催地：かがわ国際会議場   国名：日本国  

開催年月日： 2023年9月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：大阪公立大学（中百舌鳥キャンパス）   国名：日本国  

開催年月日： 2023年3月

記述言語：日本語   会議種別：ポスター発表  

開催年月日： 2023年3月

記述言語：日本語   会議種別：ポスター発表  

開催年月日： 2023年1月

記述言語：英語   会議種別：ポスター発表  

開催年月日： 2023年1月

記述言語：英語   会議種別：ポスター発表  

開催年月日： 2023年1月

記述言語：英語   会議種別：ポスター発表  

開催年月日： 2022年10月

記述言語：英語   会議種別：口頭発表（招待・特別）  

開催年月日： 2022年9月

記述言語：日本語   会議種別：口頭発表（一般）  

開催年月日： 2022年6月

記述言語：日本語   会議種別：口頭発表（一般）  

開催年月日： 2022年6月

記述言語：日本語   会議種別：口頭発表（一般）  

開催年月日： 2022年5月

記述言語：日本語   会議種別：公開講演，セミナー，チュートリアル，講習，講義等  

開催年月日： 2021年12月

記述言語：日本語   会議種別：口頭発表（一般）  

開催年月日： 2021年11月 - 2021年12月

記述言語：日本語   会議種別：ポスター発表  

開催年月日： 2021年6月

記述言語：日本語   会議種別：口頭発表（一般）  

開催年月日： 2021年3月

記述言語：英語   会議種別：口頭発表（一般）  

記述言語：日本語  

DOI： 10.14829/jcsproc.258.0_83