title: SENESCENCE-SUPPRESSED PROTEIN PHOSPHATASE Directly Interacts with the Cytoplasmic Domain of SENESCENCE-ASSOCIATED RECEPTOR-LIKE KINASE and Negatively Regulates Leaf Senescence in Arabidopsis.
abstract: Reversible protein phosphorylation mediated by protein kinases and phosphatases plays an important role in the regulation of leaf senescence. We previously reported that the leucine-rich repeat receptor-like kinase SENESCENCE-ASSOCIATED RECEPTOR-LIKE KINASE (AtSARK) positively regulates leaf senescence in Arabidopsis (Arabidopsis thaliana). Here, we report the involvement of a protein serine/threonine phosphatase 2C-type protein phosphatase, SENESCENCE-SUPPRESSED PROTEIN PHOSPHATASE (SSPP), in the negative regulation of Arabidopsis leaf senescence. SSPP transcript levels decreased greatly during both natural senescence and SARK-induced precocious senescence. Overexpression of SSPP significantly delayed leaf senescence in Arabidopsis. Protein pull-down and bimolecular fluorescence complementation assays demonstrated that the cytosol-localized SSPP could interact with the cytoplasmic domain of the plasma membrane-localized AtSARK. In vitro assays showed that SSPP has protein phosphatase function and can dephosphorylate the cytosolic domain of AtSARK. Consistent with these observations, overexpression of SSPP effectively rescued AtSARK-induced precocious leaf senescence and changes in hormonal responses. All our results suggested that SSPP functions in sustaining proper leaf longevity and preventing early senescence by suppressing or perturbing SARK-mediated senescence signal transduction.
authors: Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin 300071, China.
authors: Dong
authors: D
authors: Xiao
authors: Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin 300071, China.
authors: Yanjiao
authors: Y
authors: Cui
authors: Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin 300071, China.
authors: Fan
authors: F
authors: Xu
authors: Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin 300071, China.
authors: Xinxin
authors: X
authors: Xu
authors: Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin 300071, China.
authors: Guanxiao
authors: G
authors: Gao
authors: Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin 300071, China.
authors: Yaxin
authors: Y
authors: Wang
authors: Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin 300071, China.
authors: Zhaoxia
authors: Z
authors: Guo
authors: Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin 300071, China.
authors: Dan
authors: D
authors: Wang
authors: Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin 300071, China wangnn@nankai.edu.cn.
authors: Ning Ning
authors: http://orcid.org/0000-0001-5308-5878
authors: NN
authors: Wang
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002736:Chloroplasts / Q000502:physiology / Q000648:ultrastructure; D003583:Cytokinins / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D005030:Ethylenes / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D007210:Indoleacetic Acids / Q000378:metabolism; D008969:Molecular Sequence Data; D010749:Phosphoprotein Phosphatases / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D018515:Plant Leaves / Q000254:growth & development / Q000502:physiology*; D030821:Plants, Genetically Modified; D000071636:Protein Phosphatase 2C; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; D003583:Cytokinins; D005030:Ethylenes; D007210:Indoleacetic Acids; C036216:ethylene; D017346:Protein Serine-Threonine Kinases; C000609127:SARK protein, Arabidopsis; C000609126:At5g02760 protein, Arabidopsis; D010749:Phosphoprotein Phosphatases; D000071636:Protein Phosphatase 2C