Plant & Animal Genomes XIV Conference

January 14-18, 2006
Town & Country Convention Center
San Diego, CA

Initial Characterization Of Transgenic Rice With Large Genomic Clones Generated In Traitexplorer^Tm, A High-Throughput Screening Process For Genomic Fragments

Satoru Usami¹ , Yoshimitsu Takakura¹ , Yuko Hiei¹ , Yuji Ishida¹ , Toshiyuki Komori¹ , Toshiki Mine¹ , Masakazu Kashihara¹ , Ichiro Oka¹ , Naoki Takemori¹ , Jun Ueki¹ , Tomoaki Kubo² , Norio Katoh¹ , Toshihiko Komari¹

¹  Plant Innovation Center, Japan Tobacco Inc., 700 higashibara, iwata, shizuoka 438-0802, japan

²  National Agriculture and Bio-oriented Research Organization, National Institute of Crop Science, 2-1-18 kannondai, tsukuba, ibaraki 305-8518, japan

We have initiated a process to screen genomic fragments of higher plants that cause phenotypic changes when introduced into plants. This system was designated as TraitExplorer^TM, hoping the identification of agronomically useful phenotypes to be exploited as new traits in crop improvement. Libraries of genomic fragments ranging between about 30 kb and 40 kb in size were constructed from various Gramineae species, such as Oryza rufipogon, Rhodes grass, sorghum, Sudan grass, Italian millet and teosinte, using plant-transformation-competent cosmid vectors. Japonica rice cultivar Yukihikari was transformed with the genomic clones in a high-throughput manner. Between 2 and 5 independent transgenic events were regenerated for each of the clones, and the transformants and progeny were grown at a high density in glasshouses. Various measurements including plant height at two growth stages, panicle length and panicle weight were recorded along with overall appearance of the plants. The measured values were compared between populations of plants with clones from genomic libraries and a population of transformants that carried only a reporter gene in the T₀ generation. Each of the populations of transgenics with the genomic clones was larger than the control population in the variance in more than one measurement. Segregation of the fragments was examined by PCR or hygromycin resistance assay in the successive generations. A fraction of transgenic progeny differed from plants lacking the transgenes in certain measurements with statistical significance. These results indicate that genomic fragments with unique functions may potentially be found by this approach.