Plant Functional Genomics research at Genomics Sciences Center i

Plant Functional Genomics research at Genomics Sciences Center in RIKEN Yokohama Institute -Activation tagging lines-


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- Date/Time : Mon December 9., 2002


            PM 4-5

- Speaker : Dr. Minami Matsui (Team Leader)


            - Plant Function Exploration Team


            - Plant Functional Genomics Group


            - GSC RIKEN

- Place : Life Science Bldg. #104

- For inquires : Professor Hong Gil Nam Dept. of Life Science


         생명과학과 남홍길 교수 (☎279-2111)

Abstract -


   We are constructing large population of Arabidopsis tagging mutant lines. For the saturation mutageneisis we constructed around 40,000 Activation tagged lines and more than 8,000 Ac/Ds transposon tagging lines. We are also gathering more than 10,000 full-length cDNAs. 


   For Activation tagging lines we observed morphological alterations from seedling stage to senescence while we are constructing lines at T1 generation. We made phenotype database depended on these observations. For these phenotypic mutants we are confirming the phenotypes at T2 generation and we are also determining the T-DNA flanking sequences in the genome. Although there is some preference for the T-DNA insertion sites, they were distributed all five chromosomes. We found that flanking sequence database is very useful for the reverse genetics approaches especially for the genes making gene family. 


   I will also present the characterization of activation tagged mutant involved in light and auxin signal transduction.


A novel dominant mutant designated 'dwarf in light 1' (dfl1-D) was isolated from screening Arabidopsis activation-tagged lines. dfl1-D has a shorter hypocotyl under blue, red and far-red light, but not in darkness. Inhibition of cell elongation in shoots caused an exaggerated dwarf phenotype in the adult plant. The lateral root growth of dfl1-D was inhibited without any reduction of primary root length. The genomic DNA adjacent to the right border of T-DNA was cloned by plasmid rescue. The rescued genomic DNA contained a gene encoding a GH3 homologue. The dfl1-D showed resistance to exogenous auxin treatment. Moreover, over-expression of antisense DFL1 resulted in larger shoots and an increase in the number of lateral roots. These results indicate that the gene product of DFL1 is involved in auxin signal transduction, and inhibits shoot and hypocotyl cell elongation and lateral root cell differentiation in light.