Pleiotropic Modulation of Carbon and Nitrogen Metabolism in Arabidopsis Plants Overexpressing the<i>NAD kinase2</i>Gene

Takahashi, Hideyuki; Takahara, Kentaro; Hashida, Shin‐nosuke; Hirabayashi, Takayuki; Fujimori, Tamaki; Kawai‐Yamada, Maki; Yamaya, Tomoyuki; Yanagisawa, Shuichi; Uchimiya, Hirofumi

doi:10.1104/pp.109.140665

Cited by 79 publications

(71 citation statements)

References 60 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…6), one can rule out the first possibility. Accordingly, it is likely that the RuBP regeneration rate in NK2 lines would be enhanced through regulation of Calvin cycle enzyme by NADP(H) as an effecter (Trost et al, 2006;Takahashi et al, 2009) and/or through increase in supply of NADPH and ATP by elevated photosynthetic ETR. On the other hand, free amino acids increased in NK2 lines, Gln, Asn, and Arg are known to function as nitrogen storage compounds that include more than two nitrogen atoms in a molecule (Sieciechowicz et al, 1988;Slocum, 2005).…”

Section: Discussionmentioning

confidence: 99%

“…NADP affects virtually every metabolic pathway in the cell as a cofactor (Hunt et al, 2004;Noctor et al, 2006;Takahashi et al, 2009). To investigate whether the enlarged NADP(H) pool in NK2 lines affected the levels of metabolites, we performed comparative analysis of the steady-state levels of metabolites in the major primary pathways of photosynthetic metabolism using the well-expanded 1-month-old leaves from the vector control and NK2 lines.…”

Section: Nk2 Lines Display Differential Effects On Metabolic Intermedmentioning

confidence: 99%

See 1 more Smart Citation

Metabolome and Photochemical Analysis of Rice Plants Overexpressing Arabidopsis NAD Kinase Gene

et al. 2010

Self Cite

View full text Add to dashboard Cite

The chloroplastic NAD kinase (NADK2) is reported to stimulate carbon and nitrogen assimilation in Arabidopsis (Arabidopsis thaliana), which is vulnerable to high light. Since rice (Oryza sativa) is a monocotyledonous plant that can adapt to high light, we studied the effects of NADK2 expression in rice by developing transgenic rice plants that constitutively expressed the Arabidopsis chloroplastic NADK gene (NK2 lines). NK2 lines showed enhanced activity of NADK and accumulation of the NADP(H) pool, while intermediates of NAD derivatives were unchanged. Comprehensive analysis of the primary metabolites in leaves using capillary electrophoresis mass spectrometry revealed elevated levels of amino acids and several sugar phosphates including ribose-1,5-bisphosphate, but no significant change in the levels of the other metabolites. Studies of chlorophyll fluorescence and gas change analyses demonstrated greater electron transport and CO 2 assimilation rates in NK2 lines, compared to those in the control. Analysis of oxidative stress response indicated enhanced tolerance to oxidative stress in these transformants. The results suggest that NADP content plays a critical role in determining the photosynthetic electron transport rate in rice and that its enhancement leads to stimulation of photosynthesis metabolism and tolerance of oxidative damages.NADP is a ubiquitous coenzyme, required in various metabolic processes, since these metabolites carry electrons through the reversible conversion between oxidized (NAD + , NADP + ) and reduced (NADH, NADPH) forms in all organisms. NAD is highly oxidized and is involved primarily in intracellular catabolic reactions, whereas NADP is predominantly found in its reduced form and participates in anabolic reactions and defense against oxidative stress (Ziegler, 2000;Noctor et al., 2006;Pollak et al., 2007a). Since NAD(H) and NADP(H) play a variety of distinct physiological roles, the regulation of the NAD(H)/ NADP(H) balance is essential for cell survival (Kawai and Murata, 2008;Hashida et al., 2009).One of the key enzymes that regulates NAD(H)/ NADP(H) balance is NAD kinase (NADK; EC 2.7.1.23), which catalyzes NAD phosphorylation in the presence of ATP. The genes encoding NADK were cloned recently from all organisms investigated to date, except for Chlamydia trachomatis (Kawai and Murata, 2008). Only a single gene encoding NADK has been found in some bacteria and mammals (Kawai and Murata, 2008). In contrast, NADK activity was detected in not only the cytosol but also organelles in yeast and plant (Jarrett et al., 1982;Simon et al., 1982;Dieter and Marme, 1984;, and three genes including cytosol-type and organelle-type NADK have been cloned in yeast (Kawai et al., 2001;Outten and Culotta, 2003) and plants (Turner et al., 2004(Turner et al., , 2005.In Arabidopsis (Arabidopsis thaliana), one of the NADK isoforms is localized in the chloroplast (NADK2; Chai et al., 2005) Analysis of Arabidopsis mutants revealed low chlorophyll (chl) content, low photosynthetic activity, growth inhibi...

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Nk2 Lines Display Differential Effects On Metabolic Intermedmentioning

confidence: 99%

Metabolome and Photochemical Analysis of Rice Plants Overexpressing Arabidopsis NAD Kinase Gene

et al. 2010

Self Cite

View full text Add to dashboard Cite

show abstract

“…Homogenates were then centrifuged at 20,000g for 5 min, the supernatant was filtered through a 3-kD-cutoff filter (Millipore), and the filtrates were used for analysis. Nucleotides and ascorbate were quantified by CE-Q-TOFMS according to the method of Takahashi et al (2009). To measure DHA, 8 mL of the filtrate was added to 2 mL of 50 mM Tris-HCl (pH 7.0) containing 50 mM DTT and incubated at room temperature for 30 min to convert DHA to AsA, and the total AsA concentration was quantified by CE-Q-TOFMS.…”

Section: Metabolite Analysismentioning

confidence: 99%

The Gentio-Oligosaccharide Gentiobiose Functions in the Modulation of Bud Dormancy in the Herbaceous PerennialGentiana

et al. 2014

Self Cite

View full text Add to dashboard Cite

Bud dormancy is an adaptive strategy that perennials use to survive unfavorable conditions. Gentians (Gentiana), popular alpine flowers and ornamentals, produce overwintering buds (OWBs) that can persist through the winter, but the mechanisms regulating dormancy are currently unclear. In this study, we conducted targeted metabolome analysis to obtain clues about the metabolic mechanisms involved in regulating OWB dormancy. Multivariate analysis of metabolite profiles revealed metabolite patterns characteristic of dormant states. The concentrations of gentiobiosesignificantly varied depending on the stage of OWB dormancy, and the gentiobiose concentration increased prior to budbreak. Both activation of invertase and inactivation of b-glucosidase resulted in gentiobiose accumulation in ecodormant OWBs, suggesting that gentiobiose is seldom used as an energy source but is involved in signaling pathways. Furthermore, treatment with exogenous gentiobiose induced budbreak in OWBs cultured in vitro, with increased concentrations of sulfur-containing amino acids, GSH, and ascorbate (AsA), as well as increased expression levels of the corresponding genes. Inhibition of GSH synthesis suppressed gentiobiose-induced budbreak accompanied by decreases in GSH and AsA concentrations and redox status. These results indicate that gentiobiose, a rare disaccharide, acts as a signal for dormancy release of gentian OWBs through the AsA-GSH cycle.

show abstract

“…The extraction of metabolites was performed according to Takahashi et al (2009). Ten mg of freeze-dried samples were powdered with a Micro Smash M100 (Tomy, Tokyo, Japan), homogenized with 200 µl 50% (v/v) methanol for 10 min, and the homogenate was centrifuged at 20,000×g for 5 min.…”

Section: Measurement Of Sugar Concentration In Iowbsmentioning

confidence: 99%

High concentrations of sucrose induce overwintering bud formation in gentian plantlets cultured in vitro

Imamura

Higuchi

Sekine

et al. 2014

Plant Biotechnology

Self Cite

View full text Add to dashboard Cite

Overwintering buds (OWBs) are dormant organs produced by perennial plants. After flowering, Japanese gentians (Gentiana triflora, G. scabra and their hybrids) produce OWBs in autumn and go dormant to survive winter. Although dormant OWBs have been reported to have strong cold and freezing tolerances, no details about mechanisms and regulation are known. We attempted to produce in vitro OWBs (IOWBs) from gentian plantlets to facilitate the study of OWBs. We found that high-sucrose (6%) culturing media induced IOWB formation. IOWBs showed an enhanced freezing tolerance together with high levels of proteins and transcripts know to specifically accumulate in OWBs. Furthermore, IOWBs showed endodormancy release and bud break in the same manner as OWBs. Bud breaking in OWBs and IOWBs was promoted by red light and inhibited by far-red light. These results indicated that IOWBs possess similar physiological characteristics as OWBs, at least regarding stress tolerance and dormancy. Therefore, our artificial IOWB induction technique will be useful for the study of physiological mechanisms in field-grown OWBs.

show abstract

Pleiotropic Modulation of Carbon and Nitrogen Metabolism in Arabidopsis Plants Overexpressing theNAD kinase2Gene

Cited by 79 publications

References 60 publications

Metabolome and Photochemical Analysis of Rice Plants Overexpressing Arabidopsis NAD Kinase Gene

Metabolome and Photochemical Analysis of Rice Plants Overexpressing Arabidopsis NAD Kinase Gene

The Gentio-Oligosaccharide Gentiobiose Functions in the Modulation of Bud Dormancy in the Herbaceous PerennialGentiana

High concentrations of sucrose induce overwintering bud formation in gentian plantlets cultured in vitro

Contact Info

Product

Resources

About