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Japan International Research Center For Agricultural Science | Date: 2011-07-18

In saccharification of cellulose, chimeric -glucosidase having a region exhibiting thermophilic bacteria-derived -glucosidase activity and a module combinable to cellulose is used along with cellulosome, and at the completion of saccharification of cellulose, a cellulosic substrate is added to make the chimeric -glucosidase and cellulosome attach to the cellulosic substrate for separation.

Nakashima K.,Japan International Research Center for Agricultural science | Yamaguchi-Shinozaki K.,Japan International Research Center for Agricultural science | Yamaguchi-Shinozaki K.,University of Tokyo
Plant Cell Reports | Year: 2013

Key message: We review the recent progress on ABA signaling, especially ABA signaling for ABA-dependent gene expression, including the AREB/ABF regulon, SnRK2 protein kinase, 2C-type protein phosphatases and ABA receptors. Drought negatively impacts plant growth and the productivity of crops. Drought causes osmotic stress to organisms, and the osmotic stress causes dehydration in plant cells. Abscisic acid (ABA) is produced under osmotic stress conditions, and it plays an important role in the stress response and tolerance of plants. ABA regulates many genes under osmotic stress conditions. It also regulates gene expression during seed development and germination. The ABA-responsive element (ABRE) is the major cis-element for ABA-responsive gene expression. ABRE-binding protein (AREB)/ABRE-binding factor (ABF) transcription factors (TFs) regulate ABRE-dependent gene expression. Other TFs are also involved in ABA-responsive gene expression. SNF1-related protein kinases 2 are the key regulators of ABA signaling including the AREB/ABF regulon. Recently, ABA receptors and group A 2C-type protein phosphatases were shown to govern the ABA signaling pathway. Moreover, recent studies have suggested that there are interactions between the major ABA signaling pathway and other signaling factors in stress-response and seed development. The control of the expression of ABA signaling factors may improve tolerance to environmental stresses. © 2013 Springer-Verlag Berlin Heidelberg.

Miyakawa T.,Tokyo University of Science | Fujita Y.,Japan International Research Center for Agricultural science | Fujita Y.,University of Tsukuba | Yamaguchi-Shinozaki K.,Japan International Research Center for Agricultural science | And 2 more authors.
Trends in Plant Science | Year: 2013

The phytohormone abscisic acid (ABA) plays a crucial role in adaptive responses to environmental stresses, such as drought and high salinity, as well as in plant development, such as seed maturation and dormancy. PYR/PYL/RCAR has been identified as a bona fide ABA receptor (ABAR) that constitutes the core regulatory component of ABA signaling networks in plants. Here, we review recent structural and functional studies of the ABAR that have elucidated its activation mechanism, early signaling components, and physiological responses. A crucial event in the receptor's activation was found to be an open-to-closed conformational change in the gate loop of the receptor protein. More recent progress has provided strategies for controlling the gate's closure using chemical agonists or protein engineering approaches. © 2012 Elsevier Ltd.

Osakabe Y.,RIKEN | Yamaguchi-Shinozaki K.,University of Tokyo | Yamaguchi-Shinozaki K.,Japan International Research Center for Agricultural science | Shinozaki K.,RIKEN | Tran L.-S.P.,RIKEN
Journal of Experimental Botany | Year: 2013

Adverse environmental conditions have negative effects on plant growth and development. Receptor proteins on the plasma membrane sense various environmental stimuli and transduce them to downstream intra- and intercellular signalling networks. Receptor-like kinases (RLKs) play important roles in perceiving the extracellular ligands and activating the downstream pathway via phosphorylation of intracellular serine/threonine kinase domains. The Arabidopsis genome possesses >600 RLK-encoding genes, some of which are implicated in the perception of environmental signals during the life cycle of the sessile plants. Histidine kinases are also membrane-localized kinases and perceive osmotic stress and plant hormones. In this review, we focus on the RLKs and histidine kinases that play a role in plant response to abiotic stresses. We summarize our recent understanding of their specific roles in stress responses and absicisic acid (ABA) regulation. Elucidation of the functions of these kinases in the osmotic stress response will provide a better understanding of stress-sensing mechanisms in plants and help to identify potential candidate genes for genetic engineering of improved stress-tolerant crops.© 2013 The Author(s).

Qin F.,CAS Institute of Botany | Shinozaki K.,RIKEN | Yamaguchi-Shinozaki K.,University of Tokyo | Yamaguchi-Shinozaki K.,Japan International Research Center for Agricultural science
Plant and Cell Physiology | Year: 2011

Intensive research over the last decade has gradually unraveled the mechanisms that underlie how plants react to environmental adversity. Genes involved in many of the essential steps of the stress response have been identified and characterized. In particular, the recent discovery of ABA receptors, progress in understanding the transcriptional and post-transcriptional regulation of stress-responsive gene expression, and studies on hormone interactions under stress have facilitated addressing the molecular basis of how plant cells respond to abiotic stress. Here, we summarize recent research progress on these issues, especially focusing on progress related to the essential and classically important signaling pathways and genes. Despite this wealth of achievements, many challenges remain not only for the further elucidation of stress response mechanisms but also for evaluation of the natural genetic variations and associating them with specific gene functions. Finally, the proper application of this knowledge to benefit humans and agriculture is another important issue that lies ahead. Collaborative wisdom and efforts are needed to confront these challenges. © 2011 The Author.

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