Overexpression of OsRAN2 in rice and Arabidopsis renders transgenic plants hypersensitive to salinity and osmotic stress.
Nucleo-cytoplasmic partitioning of regulatory proteins is increasingly being recognized as a major control mechanism for the regulation of signalling in plants. Ras-related nuclear protein (Ran) GTPase is required for regulating transport of proteins and RNA across the nuclear envelope and also has roles in mitotic spindle assembly and nuclear envelope (NE) assembly. However, thus far little is known of any Ran functions in the signalling pathways in plants in response to changing environmental stimuli. The OsRAN2 gene, which has high homology (77% at the amino acid level) with its human counterpart, was isolated here. Subcellular localization results showed that OsRan2 is mainly localized in the nucleus, with some in the cytoplasm. Transcription of OsRAN2 was reduced by salt, osmotic, and exogenous abscisic acid (ABA) treatments, as determined by real-time PCR. Overexpression of OsRAN2 in rice resulted in enhanced sensitivity to salinity, osmotic stress, and ABA. Seedlings of transgenic Arabidopsis thaliana plants overexpressing OsRAN2 were overly sensitive to salinity stress and exogenous ABA treatment. Furthermore, three ABA- or stress-responsive genes, AtNCED3, AtPLC1, and AtMYB2, encoding a key enzyme in ABA synthesis, a phospholipase C homologue, and a putative transcriptional factor, respectively, were shown to have differentially induced expression under salinity and ABA treatments in transgenic and wild-type Arabidopsis plants. OsRAN2 overexpression in tobacco epidermal leaf cells disturbed the nuclear import of a maize (Zea mays L.) leaf colour transcription factor (Lc). In addition, gene-silenced rice plants generated via RNA interference (RNAi) displayed pleiotropic developmental abnormalities and were male sterile.
Zang
Aiping
A
Institute of Plant Physiology and Ecology,Graduate School of Chinese Academy of Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China.
Xu
Xiaojie
X
Neill
Steven
S
Cai
Weiming
W
D000040:Abscisic Acid / Q000494:pharmacology; D021581:Active Transport, Cell Nucleus / Q000187:drug effects; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D001483:Base Sequence; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D018076:DNA, Complementary / Q000302:isolation & purification; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D008969:Molecular Sequence Data; D012275:Oryza / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D009995:Osmosis / Q000187:drug effects; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011058:Pollen / Q000166:cytology / Q000187:drug effects / Q000648:ultrastructure; D021381:Protein Transport / Q000187:drug effects; D034622:RNA Interference; D012330:RNA, Double-Stranded / Q000378:metabolism; D054712:Salinity; D012689:Sequence Homology, Nucleic Acid; D013312:Stress, Physiological / Q000187:drug effects; D013347:Subcellular Fractions / Q000187:drug effects / Q000378:metabolism; D014170:Transformation, Genetic / Q000187:drug effects
D018076:DNA, Complementary; D010940:Plant Proteins; D012330:RNA, Double-Stranded; D000040:Abscisic Acid