The bZIP transcription factor OsABF1 is an ABA responsive element binding factor that enhances abiotic stress signaling in rice.
A number of basic leucine zipper (bZIP) transcription factors are known to function in stress signaling in plants but few have thus far been functionally characterized in rice. In our current study in rice, we have newly isolated and characterized the OsABF1 (Oryza sativa ABA responsive element binding factor 1) gene that encodes a bZIP transcription factor. Its expression in seedling shoots and roots was found to be induced by various abiotic stress treatments such as anoxia, salinity, drought, oxidative stress, cold and abscisic acid (ABA). Subcellular localization analysis in maize protoplasts using GFP fusion vectors indicated that OsABF1 is a nuclear protein. In a yeast experiment, OsABF1 was shown to bind to ABA responsive elements (ABREs) and its N-terminal region was necessary to transactivate the downstream reporter gene. The homozygous T-DNA insertional mutants Osabf1-1 and Osabf1-2 were more sensitive in response to drought and salinity treatments than wild type plants. Furthermore, the upregulated expression of some ABA/stress-regulated genes in response to ABA treatment was suppressed in these Osabf1 mutants. Our current results thus suggest that OsABF1 is involved in abiotic stress responses and ABA signaling in rice.
Amir Hossain
Md
M
Department of Bioscience and Biotechnology, The University of Suwon, Hwasung 445-743, Korea.
Lee
Yongjoo
Y
Cho
Jung-Il
JI
Ahn
Chul-Hyun
CH
Lee
Sang-Kyu
SK
Jeon
Jong-Seong
JS
Kang
Hun
H
Lee
Choon-Hwan
CH
An
Gynheung
G
Park
Phun Bum
PB
D000040:Abscisic Acid / Q000378:metabolism; D001483:Base Sequence; D050976:Basic-Leucine Zipper Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015342:DNA Probes; D018744:DNA, Plant / Q000235:genetics; D017343:Genes, Plant; D009154:Mutation; D012275:Oryza / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D013312:Stress, Physiological; D003313:Zea mays / Q000235:genetics / Q000378:metabolism
D050976:Basic-Leucine Zipper Transcription Factors; D015342:DNA Probes; D018744:DNA, Plant; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D000040:Abscisic Acid