Abstract
FOX Hunting System is useful tool for large-scale functional gene analysis. By using this system, we attempt to isolate rice genes involved in high-temperature stress tolerance. So far, we screened about 17,000 lines of transgenic Arabidopsis overexpressing rice full-length cDNA (rice FOX lines), and isolated a thermotolerant line R04333 that can survive after heat shock (42°C for 90 min). The introduced rice cDNA in R04333 encodes putative heat shock transcription factor (HSF). We generate transgenic Arabidopsis plants expressing the HSF gene (retransformant lines). Retransformant lines showed thermotolerance as R04333, concluding that thermotolerance phenotype of R04333 is caused by over-expression of HSF gene. In rice seedling, HSF gene responded to heat shock. In R04333 and retransformant plants, constitutive expression of some heat shock protein (HSP) genes was observed. Therefore, the HSF gene characterized by FOX Hunting system should be involved in thermotolerance with up-regulating HSP genes.