Summary

For systematical approach for gain-of-function we have developed the “FOX hunting system”, (Full-length cDNA over-eXpressor gene) hunting system that expresses functional full-length cDNAs individually in plants. Around 10,000 normalized Arabidopsis full-length cDNAs are cloned into plant expression Ti plasmid vector (FOX library). This FOX library was used to transform Arabidopsis by Agrobacterium in planta transformation. Each FOX line expresses one to two independent Arabidopsis full-length cDNAs. This collection of transgenic mutant lines (FOX lines) can be used for screening with various criteria from basic research to application research. Advantage of this technology is

1. Short generation time and high transformation efficiency of Arabidopsis make it possible to analyze transformed gene function in a short time. That is the function of genes of long generation time such as trees can be analyzed by this technology.
2. Using FOX lines many useful traits that cannot be obtained by conventional knockout mutation can be isolated.
3. Alternative-spliced mRNAs can be analyzed individually by using corresponding full-length cDNAs.
4. Only full-length cDNA resources are required for analysis of gene function. That is there is no need to wait for whole genome sequencing and irrespective of plant’s generation time and transformation efficiency.

Since this FOX hunting system can be applied for gene function analysis of useful plants we started joint project to search for various useful traits of rice (Rice FOX Project) with National Institute of Agrobiological Sciences (NIAS) and Research Institute for Biological Sciences (RIBS) at Okayama supported by Special Coordination Funds for Promoting Science and Technology of MEXT.