Production and characterization of a large population of cDNA-overexpressing transgenic rice plants using Gateway-based full-length cDNA expression libraries

We applied the full-length cDNA overexpressor (FOX) gene-hunting system for systematic and genome-wide functional analysis of rice genes. In this study, we constructed a novel binary vector carrying the Gateway site-specific recombination cassette and then constructed rice FOX libraries containing a maximum of 13,823 independent, full-length cDNAs (fl-cDNAs) that correspond to approximately half the total number of rice fl-cDNA clones. By introducing the FOX libraries via Agrobacterium, we generated 2,586 FOX-rice lines exhibiting various visible alterations (e.g., plant height, tillers, leaves, and heading dates). The introduced fl-cDNAs, integrated into individual transgenic rice genomes, were amplified by genomic PCR and identified using sequencing analysis. The fl-cDNAs were PCR-amplified in 2,251 (94.2%) of the 2,389 FOX-rice lines that were examined, identifying 1,920 independent fl-cDNAs in the FOX lines. In addition to the previously generated FOX-rice plants, our new collection of FOX-rice lines produced through the Gateway system should be a useful tool for the efficient identification of gene functions in rice. Moreover, this Gateway-based technology should be applicable to other species in which a collection of fl-cDNA clones is available.