Tolerance to various environmental stresses conferred by the salt-responsive rice gene ONAC063 in transgenic Arabidopsis

Environmental stresses limit plant growth and crop production worldwide. We attempted to isolate rice genes involved in conferring tolerance to environmental stresses by using a transgenic Arabidopsis population expressing full-length cDNAs of rice. Among these lines, a thermotolerant line, R08946, was detected. The rice cDNA inserted in R08946 encoded a NAC transcription factor, ONAC063. This protein was localized in the nucleus and showed transactivation activity at the C-terminus. ONAC063 expression was not induced by high-temperature but highly induced by high-salinity in rice roots. High-osmotic pressure and reactive oxygen species levels also induced ONAC063 expression. The seeds of ONAC063-expressing transgenic Arabidopsis showed enhanced tolerance to high-salinity and osmotic pressure. Microarray and real-time reverse transcription-polymerase chain reaction analyses showed upregulated expression of some salinity-inducible genes, including the amylase gene AMY1, in ONAC063-expressing transgenic Arabidopsis. Thus, ONAC063 may play an important role in eliciting responses to high-salinity stress.