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175 results on '"Morikawa, Hiromichi"'

30. Two-component high-affinity nitrate transport system in barley : Membrane localization, protein expression in roots and a direct protein-protein interaction

Author

Ishikawa, Shinji, Ito, Yuka, Sato, Yuki, Fukaya, Yuka, Takahashi, Misa, Morikawa, Hiromichi, Ohtake, Norikuni, Ohyama, Takuji, Sueyoshi, Kuni, Ishikawa, Shinji, Ito, Yuka, Sato, Yuki, Fukaya, Yuka, Takahashi, Misa, Morikawa, Hiromichi, Ohtake, Norikuni, Ohyama, Takuji, and Sueyoshi, Kuni

Abstract

A high affinity transport system (HATS) for nitrate in plants is operated by a two-component NRT2/NAR2 transport system. However, the regulation and localization of NRT2 and NAR2 at protein level are largely unknown and especially so in crop plant species. In this study with barley (Hordeum vulgare), membrane localization, protein expression in the roots, and a direct protein-protein interaction of HvNRT2 and HvNAR2 proteins were investigated. Immunochemical analysis showed that both HvNRT2 and HvNAR2 proteins were co-localized in the plasma membrane of the roots. Expression of HvNRT2 and HvNAR2 proteins was more strongly induced by treatment with higher concentrations of external nitrate, while HATS activity and transcripts for HvNRT2 and HvNAR2 were markedly repressed. An affinity column binding analysis using recombinant proteins suggests that the C-terminus of HvNRT2.1 is possibly involved in its binding to the HvNAR2.3 central region and that the Ser463 present in the HvNRT2.1 C-terminus plays a role in the binding ability.

Published
2009

31. Molecular characterization of atmospheric NO2-responsive germin-like proteins in azalea leaves

Author

Kondo, Komei, Yamada, Keizo, Nakagawa, Ayami, Takahashi, Misa, Morikawa, Hiromichi, Sakamoto, Atsushi, Kondo, Komei, Yamada, Keizo, Nakagawa, Ayami, Takahashi, Misa, Morikawa, Hiromichi, and Sakamoto, Atsushi

Abstract

Atmospheric nitrogen dioxide (NO2) is an environmental oxidant that is removed through direct uptake by foliage, but plant responses to this highly reactive gas are not well understood at the molecular level. From NO2-exposed leaves of a woody azalea (Rhododendron mucronatum), we cloned two cDNAs (RmGLP1 and RmGLP2) for germin-like proteins (GLPs), a group of ubiquitous plant proteins that have been implicated in various plant physiological and developmental processes. Quantitative analysis of mRNA expression, together with immunoblotting data, showed that foliar exposure to NO2 caused a robust induction of these GLP-encoding genes. When produced in tobacco cell culture, recombinant RmGLP2 was secreted into the apoplast, where it exhibited superoxide dismutase activity. RmGLP1 and RmGLP2 represent the first examples of plant genes that are responsive to airborne NO2. These enzymes might have a potential role in extracellular defense mechanisms through attenuation of interactions between reactive nitrogen and oxygen species.

Published
2008

33. Genetic engineering of nitrite reductase gene improves uptake and assimilation of nitrogen dioxide by Rhaphiolepis umbellata (Thunb.) Makino

Author

Shigeto, Jun, Yoshihara, Sanae, Adam, Suaad E.H., Sueyoshi, Kuni, Sakamoto, Atsushi, Morikawa, Hiromichi, Takahashi, Misa, Shigeto, Jun, Yoshihara, Sanae, Adam, Suaad E.H., Sueyoshi, Kuni, Sakamoto, Atsushi, Morikawa, Hiromichi, and Takahashi, Misa

Abstract

Hypocotyl sections of Rhaphiolepis umbellata (Thunb.) Makino were transformed by Agrobacterium tumefaciens bearing a binary vector pIG121-AtNiR, which contains cDNA of the nitrite reductase gene from Arabidopsis thaliana (Atni) under the control of a modified cauliflower mosaic virus 35S promoter and chimeric hygromycin phosphotransferase gene (hph). A 4% of the hypocotyl explants transfected with Agrobacterium formed hygromycin resistant adventitious shoots, and most of them rooted upon root induction treatment. The presence and expression of the introduced transgene in putative transgenic plants (12 months after transfection) were respectively confirmed by polymerase chain reaction (PCR) analysis using primers specific to Atni and by western blot analysis using anti NiR antibody. A total of 37 transgenic plant lines were obtained. Plants 33 months after the transfection were fumigated with 200±50 ppb 15NO2 under the natural light for one week in the fumigation chamber in a confined glasshouse. The amount of total nitrogen derived from NO2 (reflecting uptake of NO2) and that of Kjeldahl nitrogen derived from NO2 (reflecting assimilation of NO2) were determined using a mass spectrometer. One of the 9 transgenic plants tested was 1.6–2.0 times higher both in the uptake and assimilation of NO2 than non-transformed wild-type ones.

Published
2006

50. Nitrogen dioxide regulates organ growth by controlling cell proliferation and enlargement in Arabidopsis.

Author

Takahashi, Misa, Furuhashi, Takamasa, Ishikawa, Naoko, Horiguchi, Gorou, Sakamoto, Atsushi, Tsukaya, Hirokazu, and Morikawa, Hiromichi

Subjects
NITROGEN dioxide, ARABIDOPSIS thaliana, CELL proliferation, NITRIC oxide, PLANT biomass, LEAF development
Abstract

To gain more insight into the physiological function of nitrogen dioxide ( NO2), we investigated the effects of exogenous NO2 on growth in Arabidopsis thaliana., Plants were grown in air without NO2 for 1 wk after sowing and then grown for 1-4 wk in air with (designated treated plants) or without (control plants) NO2. Plants were irrigated semiweekly with a nutrient solution containing 19.7 mM nitrate and 10.3 mM ammonium., Five-week-old plants treated with 50 ppb NO2 showed a ≤ 2.8-fold increase in biomass relative to controls. Treated plants also showed early flowering. The magnitude of the effects of NO2 on leaf expansion, cell proliferation and enlargement was greater in developing than in maturing leaves. Leaf areas were 1.3-8.4 times larger on treated plants than corresponding leaves on control plants. The NO2-induced increase in leaf size was largely attributable to cell proliferation in developing leaves, but was attributable to both cell proliferation and enlargement in maturing leaves. The expression of different sets of genes for cell proliferation and/or enlargement was induced by NO2, but depended on the leaf developmental stage., Collectively, these results indicated that NO2 regulates organ growth by controlling cell proliferation and enlargement. [ABSTRACT FROM AUTHOR]

Published
2014
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