Involvement of rice transcription factor OsERF19 in response to ABA and salt stress responses.

Soil salinity is a major environmental stressor that restricts the growth and yield of crops. Plants have evolved more complicated and precise mechanisms to cope with salt stress, as they cannot escape from harmful environments. In the current study we identified and characterized an AP2/ERF transcription factor in rice, OsERF19. The expression of OsERF19 was slightly repressed by salt stress or abscisic acid (ABA) treatment. OsERF19-overexpression (OsERF19-OX) plants displayed enhanced tolerance to salt stress and ABA hypersensitivity compared to wild type and control plants. Furthermore, OsLEA3, OsNHX1, OsHKT6, and OsOTS1 were upregulated in OsERF19-OX plants when the plants were subjected to salt stress. OsRAB21, OsNCED5, and OsP5CS1 were also upregulated in OsERF19-OX plants treated with ABA. Yeast one-hybrid and dual luciferase reporter assays demonstrated that OsERF19 directly targets the promoters of OsOTS1 and OsNCED5 and further increases their transcription. These results suggest that the transcription factor OsERF19 plays a positive role in salt stress and ABA responses in rice.