[Show abstract][Hide abstract] ABSTRACT: S-RBP11, a chloroplast protein, which was isolated using activation tagging system, is shown to be the first Arabidopsis small RNA-binding group protein involved in oxidative and salt stress responses. Activation tagging is one of the most powerful tools in reverse genetics. In this study, we isolated S-RBP11, encoding a small RNA-binding protein in Arabidopsis, by salt-resistant activation tagging line screen and then characterized its function in the abiotic stress response. The isolated activation tagging line of S-RBP11 as well as transgenic plants overexpressing S-RBP11 showed increased tolerance to salt and MV stresses compared to WT plants, whereas s-rbp11 mutants were more sensitive to salt stresses. Transcription of S-RBP11 was elevated upon MV treatment but not NaCl or cold treatment. Interestingly, S-RBP11 protein was localized in the chloroplast and the N-terminal 34 amino acid region of S-RBP11 was necessary for its chloroplast targeting. Our results suggest that S-RBP11 is a chloroplast protein involved in the responses to salt and oxidative stresses.
[Show abstract][Hide abstract] ABSTRACT: Various transcription factors are involved in the response to environmental stresses in plants. In this study, we characterized AtERF71/HRE2, a member of the Arabidopsis AP2/ERF family, as an important regulator of the osmotic and hypoxic stress responses in plants. Transcript level of AtERF71/HRE2 was highly increased by anoxia, NaCl, mannitol, ABA, and MV treatments. aterf71/hre2 loss-of-function mutants displayed higher sensitivity to osmotic stress such as high salt and mannitol, accumulating higher levels of ROS under high salt treatment. In contrast, AtERF71/HRE2-overexpressing transgenic plants showed tolerance to salt and mannitol as well as flooding and MV stresses, exhibiting lower levels of ROS under high salt treatment. AtERF71/HRE2 protein was localized in the nucleus, and the C-terminal region of AtERF71/HRE2 was required for transcription activation activity. Taken together, our results suggest that AtERF71/HRE2 might function as a transcription factor involved in the response to osmotic stress as well as hypoxia.
Biochemical and Biophysical Research Communications 09/2011; 414(1):135-41. · 2.28 Impact Factor