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Our laboratory is engaged in the research and education pertaining to biotechnology needed to resolve the issues for human beings in the 21st century such as food, environments and energy. Using methods of molecular biology based on genomic information, we are clarifying the mechanism for regulation of gene expression in plants and molecular breeding of stress-resistant plants and trees making use of biological functions.
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- 1. Analysis of molecular mechanism controlling xylem cells differentiation.
Xylem functions in conduction of water and minerals throughout the plants, and supports the plant body. One of the features of xylem cells is development of secondary wall structure between plasma membrane and (primary) cell wall. Recently, it is expected that knowledge on xylem development can be utilized for application of improvement of the plant biomass, since most portion of wood, which represents one of important sources of woody biomass, is mainly composed of two types of xylem cells, xylem vessels and fiber cells.
Previously we established the in vitro transdifferentiation system into xylem vessel elements from Arabidopsis suspension cells. A number of genes whose expression is elevated during the transdifferentiation processes have been isolated by using microarray analysis. We revealed that one of the identified genes, which encoded a NAC domain protein, VND7 (Vascular-Related NAC Domain Protein7), acts as a key regulator of the xylem vessel differentiation (Fig. 1). To understand the molecular mechanism by which xylem vessel formation is regulated, we have been characterizing VND7 and its homologs with various approaches. Recently, we have identified interacting proteins with VND7 (Fig. 2) and direct target genes of VND7. We expect that the results obtained through our experiments will lead to the improvement of plant biomass production in the future.
- Molecular and cell biological approaches to trees.
Based on the information about model plant, we also study about molecular mechanisms of stress tolerance and flowering in tree. By taking advantage of our knowledge from these studies, we will be able to generate the transgenic trees with useful traits (Fig. 3).
- High-efficient expression system of transgenes in higher plants
Efficient Transcription and Translation?In order to transcribe a foreign gene in plant cells more effectively, we are studying about the factors of the transgene-silencing, the relationship between chromatin/ nucleosome structure around promoter region and gene expression, identification and characterization of matrix attachment region (MAR), improvement of transcriptional terminator region. In addition to increasing transcription, it is important to maximize the amount of protein translated per unit mRNA. Therefore, we are studying about identification and characterization of translational enhancer, effect of context of AUG codon on translation efficiency, translation under stress condition (Fig. 4).
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- Matsui T. et al., Transgenic Res., in press
- Yamaguchi M. et al., Plant J., in press
- Matsui T. et al., Plant Cell Physiol., 52. 413-420
- Matsuura H. et al., Plant Cell Physiol., 51. 448-462, 2010
- Nagaya S. et al., Plant Cell Physiol., 51. 328-332, 2010
- Matsuura H. et al., Biosci. Siotechnol. Biochemi., 74. 2210-2212, 2010
- Sugio T. et al., J. Biosci. Bioeng., 109, 170-173, 2010
- Demura T. & Ye ZH., , Curr. Opin. Plant Biol., 13. 299-304, 2010
- Yamaguchi M. et al., Plant Cell, 22. 1249-1263, 2010
- Yamaguchi M. et al., Plant physiol., 153. 906-914, 2010
- Nakano Y. et al., Plant Biotechnol., 27. 267-272, 2010
- Yamaguchi M. & Demura T., Plant Biotechnol., 27. 237-242, 2010
- Matsui T. et al., Biosci. Siotechnol. Biochemi., 73. 1628-1634, 2009
- Endo S. et al., Plant Cell, 21. 1155-1165, 2009
- 出村 拓, 蛋白質核酸酵素, 54. 259-266, 2009
- Ichikawa K. et al., Plant Cell Physiol., 49. 214-225, 2005
- Kubo M. et al., Genes Dev., 19. 1855-1860, 2005
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Fig. 1 VND7 acts as a key regulator of the xylem vessel differentiation
Overexpression of VND7 induces transdifferentiation of epidermal cells into xylem vessel elements with spiral structure of secondary wall thickening (arrows) in hypocotyle. Bar=100 μm.
Fig. 2 VNI2 is a negative regulator of the xylem vessel differentiation
VNI2 has been isolated as an interacting protein with VND7. Discontinuous structure of the xylem vessels are observed in VNI2 overexpression line. Bar = 1 mm.
Fig. 3 Molecular breeding for obtaining trees with useful traits
Fig. 4 Clarification of the mechanism for regulation of gene expression in plants
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