The phs1-3 mutation in a putative dual-specificity protein tyrosine phosphatase gene provokes hypersensitive responses to abscisic acid in Arabidopsis thaliana.
The plant hormone abscisic acid (ABA) controls numerous physiological traits: dormancy and germination of seeds, senescence and resistance to abiotic stresses. In order to get more insight into the role of protein tyrosine phosphatase (PTP) in ABA signalling, we obtained eight homozygous T-DNA insertion lines in Arabidopsis thaliana PTP genes. One mutant, named phs1-3, exhibited a strong ABA-induced inhibition of germination as only 26% of its seeds germinated after 3 days instead of 92% for the Columbia (Col-0) line. Genetic and molecular analyses of phs1-3 showed that it bears a unique T-DNA insertion in the promoter of the gene and that the mutation is recessive. PHS1 expression in the mutant is about half that of the Col-0 line. The upregulation of two ABA-induced genes (At5g06760, RAB18) and the downregulation of two ABA-repressed genes (AtCLC-A, ACL) are enhanced in the phs1-3 mutant compared with the wild-type. The 'in planta' aperture of phs1-3 stomata is reduced and the inhibition of the light-induced opening of stomata by ABA is stronger in phs1-3 leaves than in Col-0 leaves. Finally, PHS1 expression is upregulated in the presence of ABA in both phs1-3 and Col-0 but more intensively in the mutant. Thus, phs1-3 is hypersensitive to ABA. Taken together, these results show that PHS1, which encodes a dual-specificity PTP, is a negative regulator of ABA signalling.
Quettier
Anne-Laure
AL
Université Pierre et Marie Curie-Paris 6, FRE 2846, PCMP, Ivry-sur-Seine, F-94200, France.
Bertrand
Claire
C
Habricot
Yvette
Y
Miginiac
Emile
E
Agnes
Christiane
C
Jeannette
Emmanuelle
E
Maldiney
Régis
R
D000040:Abscisic Acid / Q000494:pharmacology*; D017360:Arabidopsis / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D018525:Germination / Q000187:drug effects; D008027:Light; D009154:Mutation; D010937:Plant Growth Regulators / Q000494:pharmacology*; D017027:Protein Tyrosine Phosphatases / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D015398:Signal Transduction
D029681:Arabidopsis Proteins; D010937:Plant Growth Regulators; D000040:Abscisic Acid; C514675:PHS1 protein, Arabidopsis; D017027:Protein Tyrosine Phosphatases