Agrogenomics Research Center

Plant Genome Engineering Research Unit

　In conventional mutation breeding technology using chemical mutagens and ionizing radiation, it remains quite diffi cult to select mutants harboring target genes modified exactly as required, because mutations occur randomly. Site-directed mutagenesis via gene targeting (GT) is the ultimate mutation breeding technology. However, GT efficiency is still low due to lower frequency of homologous recombination in higher plants. We are trying to establish an efficient and reproducible GT system in higher plants based on the understanding of basic mechanisms controlling homologous recombination and non-homologous end joining in higher plants.
The development of technologies to enhance/repress expression of genes of interest is important for research on gene function. For this purpose, we seek to develop technologies to efficiently introduce and express genes of interest efficiently in higher plant cells. Furthermore, we discover basic mechanisms of genome shuffling for efficient production of unprecedented crop lines with favorable characteristics.

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  Schematic representation of designed-mutation breeding in plantsvia homologous recombination-mediated gene targeting (GT)

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  Production of herbicide tolerant rice via gene targeting

  (a) Herbicide tolerant callus emerged after GT.
  (b) Herbicide tolerant GT rice (right) and sensitive original rice (left). Introduction of the two point mutations confers herbicide tolerant phenotype in rice.