Press Releases
Dec. 2, 2009

Identification of an effective combination of genes that improve leaf size

  • Gorou Horiguchi (Associate professor, College of Science, Rikkyo University)
  • Hirokazu Tsukaya (Professor, Department of Biological Sciences, The University of Tokyo)
Figure 1

Fig. A segmental chromosomal duplication induces the large-leaf phenotype in the gra-D mutants. Fully expanded first leaves of wild type (top, left) and gra-D (top, right). The position of the segmental chromosomal duplication in the gra-D mutants (bottom). The blue band shows the entire region of chromosome 4. In the x-axis, individual genes are indicated by blue lines. In the y-axis, gene contents in gra-D relative to wild type are shown. Note that the right most region of the chromosome contains two-fold higher number of genes.

How organ size of plants is determined is not only a fundamental biological issue but also an important target of applied research to improve productivity of plants. grandifolida-D (gra-D) mutants of Arabidopsis thaliana produce two to three fold larger leaves than wild type does due to enhanced cell proliferation in leaf primordia (Fig. 1, top). The gra-D mutants have a chromosomal duplication that contains about 1000 genes (Fig. 1, bottom). This region contains AINTEGUMENTA (ANT) encoding a transcription factor and CYCD3;1 encoding a cyclin. When both genes are up-regulated simultaneously, significantly larger leaves are produced as compared with wild type or transgenic plants in which either one of two genes was up-regulated. Thus, our study points out a potential usefulness of mutants induced by a segmental chromosomal duplication to discover combinations of useful genes that is difficult by the characterization of single genes.

Paper information

The Plant Journal 60, 122-133 (2009)
Impact of segmental chromosomal duplications on leaf size in the grandifolia-D mutants of Arabidopsis thaliana
Gorou Horiguchi, Nathalie Gonzalez, Gerrit T. S. Beemster, Dirk Inzé, Hirokazu Tsukaya