Expression of Cyanobacterial Acyl-ACP Reductase Elevates the Triacylglycerol Level in the Red Alga Cyanidioschyzon merolae
Nitrogen starvation is known to induce the accumulation of triacylglycerol (TAG) in many microalgae, and potential use of microalgae as a source of biofuel has been explored. However, nitrogen starvation also stops cellular growth. The expression of cyanobacterial acyl-acyl carrier protein (ACP) reductase in the unicellular red alga Cyanidioschyzon merolae chloroplasts resulted in an accumulation of TAG, which led to an increase in the number and size of lipid droplets while maintaining cellular growth. Transcriptome and metabolome analyses showed that the expression of acyl-ACP reductase altered the activities of several ...
Source: Plant and Cell Physiology - October 8, 2015 Category: Cytology Authors: Sumiya, N., Kawase, Y., Hayakawa, J., Matsuda, M., Nakamura, M., Era, A., Tanaka, K., Kondo, A., Hasunuma, T., Imamura, S., Miyagishima, S.-y. Tags: Regular Papers Source Type: research
Molecular Characterization of TaFAR1 Involved in Primary Alcohol Biosynthesis of Cuticular Wax in Hexaploid Wheat
Cuticular waxes are complex mixtures of very long chain (VLC) fatty acids and their derivatives in which primary alcohols are the most abundant components in the leaf surface of common wheat (Triticum aestivum L.). However, the genes involved in primary alcohol biosynthesis in wheat are still largely unknown. Here we identified, via a homology-based approach, the TaFAR1 gene belonging to the fatty acyl-CoA reductases (FARs) from wheat. Heterologous expression of TaFAR1 in yeast (Saccharomyces cerevisiae) and in the Arabidopsis (Arabidopsis thaliana) cer4-3 mutant afforded production of C22 primary alcohol and C22–C24...
Source: Plant and Cell Physiology - October 8, 2015 Category: Cytology Authors: Wang, Y., Wang, M., Sun, Y., Hegebarth, D., Li, T., Jetter, R., Wang, Z. Tags: Regular Papers Source Type: research
Identification and Analysis of Medicago truncatula Auxin Transporter Gene Families Uncover their Roles in Responses to Sinorhizobium meliloti Infection
Auxin transport plays a pivotal role in the interaction between legume species and nitrogen-fixing bacteria to form symbioses. Auxin influx carriers auxin resistant 1/like aux 1 (AUX/LAX), efflux carriers pin-formed (PIN) and efflux/conditional P-glycoprotein (PGP/ABCB) are three major protein families participating in auxin polar transport. We used the latest Medicago truncatula genome sequence to characterize and analyze the M. truncatula LAX (MtLAX), M. truncatula PIN (MtPIN) and M. truncatula ABCB (MtABCB) families. Transient expression experiments indicated that three representative auxin transporters (MtLAX3, MtPIN7 ...
Source: Plant and Cell Physiology - October 8, 2015 Category: Cytology Authors: Shen, C., Yue, R., Bai, Y., Feng, R., Sun, T., Wang, X., Yang, Y., Tie, S., Wang, H. Tags: Regular Papers Source Type: research
Resolving the Role of Plant NAD-Glutamate Dehydrogenase: III. Overexpressing Individually or Simultaneously the Two Enzyme Subunits Under Salt Stress Induces Changes in the Leaf Metabolic Profile and Increases Plant Biomass Production
NAD-dependent glutamate dehydrogenase (NAD-GDH) of higher plants has a central position at the interface between carbon and nitrogen metabolism due to its ability to carry out the deamination of glutamate. In order to obtain a better understanding of the physiological function of NAD-GDH under salt stress conditions, transgenic tobacco (Nicotiana tabacum L.) plants that overexpress two genes from Nicotiana plumbaginifolia individually (GDHA and GDHB) or simultaneously (GDHA/B) were grown in the presence of 50 mM NaCl. In the different GDH overexpressors, the NaCl treatment induced an additional increase in GDH enzyme activ...
Source: Plant and Cell Physiology - October 8, 2015 Category: Cytology Authors: Terce-Laforgue, T., Clement, G., Marchi, L., Restivo, F. M., Lea, P. J., Hirel, B. Tags: Regular Papers Source Type: research
Apple MdACS6 Regulates Ethylene Biosynthesis During Fruit Development Involving Ethylene-Responsive Factor
Ethylene biosynthesis in plants involves different 1-aminocyclopropane-1-carboxylic acid synthase (ACS) genes. The regulation of each ACS gene during fruit development is unclear. Here, we characterized another apple (Malusxdomestica) ACS gene, MdACS6. The transcript of MdACS6 was observed not only in fruits but also in other tissues. During fruit development, MdACS6 was initiated at a much earlier stage, whereas MdACS3a and MdACS1 began to be expressed at 35 d before harvest and immediateley after harvest, respectively. Moreover, the enzyme activity of MdACS6 was significantly lower than that of MdACS3a and MdACS1, accoun...
Source: Plant and Cell Physiology - October 8, 2015 Category: Cytology Authors: Li, T., Tan, D., Liu, Z., Jiang, Z., Wei, Y., Zhang, L., Li, X., Yuan, H., Wang, A. Tags: Regular Papers Source Type: research
Cuticle Affects Calculations of Internal CO2 in Leaves Closing Their Stomata
Analyzing the assimilation rate (A) relative to the CO2 concentration inside leaves (Ci) has been a useful approach for investigating plant responses to various environments. Nevertheless, there are uncertainties in calculating Ci when stomata close, restricting the application. Here, A–Ci curves were traced in sunflower (Helianthus annuus L.) leaves using a method for directly measuring Ci. The method was incorporated into an LI-6400 open gas exchange system, and stomata were closed by feeding 10 µM ABA through petioles. The conductance to CO2 was derived from the directly measured Ci and compared with the con...
Source: Plant and Cell Physiology - October 8, 2015 Category: Cytology Authors: Tominaga, J., Kawamitsu, Y. Tags: Regular Papers Source Type: research
Is Monoglucosyldiacylglycerol a Precursor to Monogalactosyldiacylglycerol in All Cyanobacteria?
In this study, I determined the structure of GlcDG from Anabaena variabilis by 1H- and 13C-nuclear magnetic resonance (NMR) spectroscopy. I then showed that G. violaceus, T. elongatus, A. marina and P. marinus contain GlcDG. In all cases, GlcDG consisted of fewer unsaturated molecular species than MGDG, providing further evidence that GlcDG is a precursor to MGDG. The conversion of GlcDG to MGDG was also demonstrated by radiolabeling and chase experiments in G. violaceus and P. marinus. These results demonstrate that all the analyzed cyanobacteria contain GlcDG, which is converted to MGDG, and suggest that an alternative e...
Source: Plant and Cell Physiology - October 8, 2015 Category: Cytology Authors: Sato, N. Tags: Regular Papers Source Type: research
Methyl Jasmonate-Induced Lipidomic and Biochemical Alterations in the Intertidal Macroalga Gracilaria dura (Gracilariaceae, Rhodophyta)
The role of exogenously added methyl jasmonate (MeJA), a lipid-derived signaling compound, in inducing oxidative stress in the marine red macroalga Gracilaria dura was investigated. MeJA at a concentration of 1–100 µM was a strong stimulant of reactive oxygen species (H2O2, HO· and O2·–) (P < 0.05) causing considerable oxidative stress in G. dura. This further led to lipid peroxidation and degradation of the pigments Chl a and phycocyanin, with a concomitant increase in phycoerythrin. The MeJA-induced oxidative burst also led to the induction of a fatty acid oxidation cascade, resulting i...
Source: Plant and Cell Physiology - October 8, 2015 Category: Cytology Authors: Kumari, P., Reddy, C. R. K., Jha, B. Tags: Regular Papers Source Type: research
Stress Tolerance Profiling of a Collection of Extant Salt-Tolerant Rice Varieties and Transgenic Plants Overexpressing Abiotic Stress Tolerance Genes
In this study, we investigated the profiles of stress tolerance of nine salt-tolerant rice varieties and transgenic rice lines carrying constitutively expressed genes that are potentially involved in salt tolerance, by evaluating their growth and viability under salt, heat, ionic and hyperosmotic stress conditions. Profiling of the extant varieties and selected chromosome segment substitution lines showed that salt tolerance in a greenhouse condition was more tightly correlated with ionic stress tolerance than osmotic stresses. In Nona Bokra, one of the most salt-tolerant varieties, the contribution of the previously ident...
Source: Plant and Cell Physiology - October 8, 2015 Category: Cytology Authors: Kurotani, K.-i., Yamanaka, K., Toda, Y., Ogawa, D., Tanaka, M., Kozawa, H., Nakamura, H., Hakata, M., Ichikawa, H., Hattori, T., Takeda, S. Tags: Regular Papers Source Type: research
Calpain-Mediated Positional Information Directs Cell Wall Orientation to Sustain Plant Stem Cell Activity, Growth and Development
Eukaryotic development and stem cell control depend on the integration of cell positional sensing with cell cycle control and cell wall positioning, yet few factors that directly link these events are known. The DEFECTIVE KERNEL1 (DEK1) gene encoding the unique plant calpain protein is fundamental for development and growth, being essential to confer and maintain epidermal cell identity that allows development beyond the globular embryo stage. We show that DEK1 expression is highest in the actively dividing cells of seeds, meristems and vasculature. We further show that eliminating Arabidopsis DEK1 function leads to change...
Source: Plant and Cell Physiology - September 8, 2015 Category: Cytology Authors: Liang, Z., Brown, R. C., Fletcher, J. C., Opsahl-Sorteberg, H.-G. Tags: Regular Papers Source Type: research
Rate Constants of PSII Photoinhibition and its Repair, and PSII Fluorescence Parameters in Field Plants in Relation to their Growth Light Environments
We examined these rate constants and fluorescence parameters of several field-grown plants to determine inter-relationships between these values and the growth environment. The kpi values were strongly related to the excess energy, EY, of the puddle model and non-regulated energy dissipation, Y(NO), of the lake model, both multiplied by the photosynthetically active photon flux density (PPFD) level during the photoinhibitory treatment. In contrast, the krec values corrected against in situ air temperature were very strongly related to the daily PPFD level. The plants from the fields showed higher NPQ than the chamber-grown...
Source: Plant and Cell Physiology - September 8, 2015 Category: Cytology Authors: Miyata, K., Ikeda, H., Nakaji, M., Kanel, D. R., Terashima, I. Tags: Regular Papers Source Type: research
Control of the Water Transport Activity of Barley HvTIP3;1 Specifically Expressed in Seeds
Tonoplast intrinsic proteins (TIPs) are involved in the transport and storage of water, and control intracellular osmotic pressure by transporting material related to the water potential of cells. In the present study, we focused on HvTIP3;1 during the periods of seed development and desiccation in barley. HvTIP3;1 was specifically expressed in seeds. An immunochemical analysis showed that HvTIP3;1 strongly accumulated in the aleurone layers and outer layers of barley seeds. The water transport activities of HvTIP3;1 and HvTIP1;2, which also accumulated in seeds, were measured in the heterologous expression system of Xenop...
Source: Plant and Cell Physiology - September 8, 2015 Category: Cytology Authors: Utsugi, S., Shibasaka, M., Maekawa, M., Katsuhara, M. Tags: Regular Papers Source Type: research
Plants Possess a Cyclic Mitochondrial Metabolic Pathway similar to the Mammalian Metabolic Repair Mechanism Involving Malate Dehydrogenase and L-2-Hydroxyglutarate Dehydrogenase
Enzymatic side reactions can give rise to the formation of wasteful and toxic products that are removed by metabolite repair pathways. In this work, we identify and characterize a mitochondrial metabolic repair mechanism in Arabidopsis thaliana involving malate dehydrogenase (mMDH) and l-2-hydroxyglutarate dehydrogenase (l-2HGDH). We analyze the kinetic properties of both A. thaliana mMDH isoforms, and show that they produce l-2-hydroxyglutarate (l-2HG) from 2-ketoglutarate (2-KG) at low rates in side reactions. We identify A. thaliana l-2HGDH as a mitochondrial FAD-containing oxidase that converts l-2HG back to 2-KG. Usin...
Source: Plant and Cell Physiology - September 8, 2015 Category: Cytology Authors: Hudig, M., Maier, A., Scherrers, I., Seidel, L., Jansen, E. E. W., Mettler-Altmann, T., Engqvist, M. K. M., Maurino, V. G. Tags: Regular Papers Source Type: research
RING Type E3 Ligase CaAIR1 in Pepper Acts in the Regulation of ABA Signaling and Drought Stress Response
Several E3 ubiquitin ligases have been associated with the response to abiotic and biotic stresses in higher plants. Here, we report that the hot pepper (Capsicum annuum) ABA-Insensitive RING protein 1 gene (CaAIR1) is essential for a hypersensitive response to drought stress. CaAIR1 contains a C3HC4-type RING finger motif, which plays a role for attachment of ubiquitins to the target protein, and a putative transmembrane domain. The expression levels of CaAIR1 are up-regulated in pepper leaves by ABA treatments, drought and NaCl, suggesting its role in the response to abiotic stress. Our analysis showed that CaAIR1 displa...
Source: Plant and Cell Physiology - September 8, 2015 Category: Cytology Authors: Park, C., Lim, C. W., Baek, W., Lee, S. C. Tags: Regular Papers Source Type: research
Overexpression of ALDH10A8 and ALDH10A9 Genes Provides Insight into Their Role in Glycine Betaine Synthesis and Affects Primary Metabolism in Arabidopsis thaliana
Betaine aldehyde dehydrogenases oxidize betaine aldehyde to glycine betaine in species that accumulate glycine betaine as a compatible solute under stress conditions. In contrast, the physiological function of betaine aldehyde dehydrogenase genes is at present unclear in species that do not accumulate glycine betaine, such as Arabidopsis thaliana. To address this question, we overexpressed the Arabidopsis ALDH10A8 and ALDH10A9 genes, which were identified to code for betaine aldehyde dehydrogenases, in wild-type A. thaliana. We analysed changes in metabolite contents of transgenic plants in comparison with the wild type. U...
Source: Plant and Cell Physiology - September 8, 2015 Category: Cytology Authors: Missihoun, T. D., Willee, E., Guegan, J.-P., Berardocco, S., Shafiq, M. R., Bouchereau, A., Bartels, D. Tags: Regular Papers Source Type: research
