title: Functional analysis in Arabidopsis of FsPTP1, a tyrosine phosphatase from beechnuts, reveals its role as a negative regulator of ABA signaling and seed dormancy and suggests its involvement in ethylene signaling modulation.
abstract: By means of an RT-PCR approach we isolated a specific tyrosine phosphatase (FsPTP1) induced by abscisic acid (ABA) and correlated with seed dormancy in Fagus sylvatica seeds. To provide genetic evidence of FsPTP1 function in seed dormancy and ABA signal transduction pathway, we overexpressed this gene in Cape Verde Island ecotype of Arabidopsis thaliana, which shows the deepest degree of seed dormancy among Arabidopsis accessions. As a result, 35S:FsPTP1 transgenic seeds showed a reduced dormancy and insensitivity to ABA and osmotic stress conditions accompanied by a reduction in the level of expression of RAB18 and RD29, well-known ABA-responsive genes. Taken together, all these data are consistent with a role of this tyrosine phosphatase as a negative regulator of ABA signaling. In addition, phenotypes of FsPTP1 transgenic plants resemble those observed in ethylene constitutive mutants, accompanied by an increase in the level of expression of a key gene involved in ethylene signaling such as EIN2. All the data presented along the paper suggest that the effect of tyrosine phosphatases in ABA action during the transition from seed dormancy to germination may be through modulation of ethylene signaling.
authors.affiliation: Departamento de Fisiología Vegetal, Centro Hispano-Luso de Investigaciones Agrarias, Facultad de Biología, Universidad de Salamanca, C/Río Duero 12, Campus de Villamayor, 37185 Salamanca, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Alonso-Ramírez
authors.forename: Dolores
authors.initials: D
authors.lastname: Rodríguez
authors.forename: David
authors.initials: D
authors.lastname: Reyes
authors.forename: Jesús A
authors.initials: JA
authors.lastname: Jiménez
authors.forename: Gregorio
authors.initials: G
authors.lastname: Nicolás
authors.forename: Carlos
authors.initials: C
authors.lastname: Nicolás
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D005030:Ethylenes / Q000378:metabolism; D029964:Fagus / Q000201:enzymology* / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D057445:Plant Dormancy / Q000502:physiology*; D010937:Plant Growth Regulators / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism*; D030821:Plants, Genetically Modified; D017027:Protein Tyrosine Phosphatases / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D005030:Ethylenes; D010937:Plant Growth Regulators; D010940:Plant Proteins; D000040:Abscisic Acid; C036216:ethylene; D017027:Protein Tyrosine Phosphatases