title: Expression profiling and functional characterization of a CBL-interacting protein kinase gene from Populus euphratica.
abstract: This is the first report on the function of a member of the CIPK family in Populus euphratica. The Ca(2+)-dependent salt overly sensitive (SOS) pathway has been shown to play an essential role in maintaining ion homeostasis and conferring salt tolerance. One component of the SOS pathway, SOS1, was identified in the salt-resistant tree P. euphratica. In this study, we identified and functionally characterized another component of the SOS pathway in this tree called PeSOS2 or PeCIPK26. On the basis of protein sequence similarity and complementation studies in Arabidopsis, PeCIPK26 was concluded to be the functional homolog of Arabidopsis AtSOS2. Yeast two-hybrid assays revealed that PeCIPK26 can interact with four calcineurin B-like (CBL) genes, i.e., PeCBL1, PeCBL4/PeSOS3, PeCBL9 and PeCBL10. Autophosphorylation assays showed that PeCIPK26 is an active protein kinase. Expression profile analysis demonstrated that PeCIPK26 is expressed in root, stem and leaf, and throughout the cell including cell membrane, cytoplasm and nucleus; in addition, it can be induced under salt-stress treatment. Functions of PeCIPK26 in salt tolerance were evaluated by gene overexpression in Arabidopsis cipk24 mutants. The better salt tolerance of transgenic plants relative to mutants was shown by their higher germination rate, lower Na(+) accumulation and higher capacity to discharge Na(+) when grown with NaCl. These results suggest the involvement of PeCIPK26 in the salt-stress response of P. euphratica.
authors.affiliation: College of Biological Sciences and Technology, National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing, 100083, People's Republic of China.
authors.forename: Fuling
authors.initials: F
authors.lastname: Lv
authors.forename: Hechen
authors.initials: H
authors.lastname: Zhang
authors.forename: Xinli
authors.initials: X
authors.lastname: Xia
authors.forename: Weilun
authors.initials: W
authors.lastname: Yin
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics / Q000502:physiology; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D005816:Genetic Complementation Test; D006706:Homeostasis; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000201:enzymology / Q000235:genetics / Q000502:physiology; D030821:Plants, Genetically Modified; D032107:Populus / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D055049:Salt Tolerance; D012492:Salts; D016415:Sequence Alignment; D012964:Sodium / Q000378:metabolism; D013312:Stress, Physiological; D020798:Two-Hybrid System Techniques
chemical_list: D010940:Plant Proteins; D012492:Salts; D012964:Sodium; D017346:Protein Serine-Threonine Kinases