ABSTRACT
The homozygous T-DNA mutant of the PP2CA2 gene in Arabidopsis thaliana was identified at DNA and RNA levels. The semi-quantitative RT-PCR analysis showed expression of PP2CA2 was induced by NaCl and ABA. When grown in presence of increasing concentration of exogenous ABA the pp2ca2 mutant showed a significant loss of ABA sensitivity in terms of seed germination, efficiency of post-germination growth and root growth. In presence of all ABA and NaCl concentrations tested the germination percentage of wild-type seeds was lower than that of mutant ppca2 seeds. Furthermore, in the presence of exogenous ABA, the pp2ca2 seeds showed higher germination percentages than wild-type at different stages of development and the pp2ca2 seedlings showed a reduced inhibition of root growth compared with wild-type plants. The above results indicated that the pp2ca2 was an ABA-hyposensitive mutant.
Subject(s)
Abscisic Acid/metabolism , Arabidopsis/genetics , Phosphoprotein Phosphatases/genetics , Abscisic Acid/pharmacology , Acclimatization/genetics , Amino Acid Sequence , Arabidopsis/growth & development , Arabidopsis Proteins/genetics , DNA Mutational Analysis , Gene Expression Regulation, Enzymologic/drug effects , Gene Expression Regulation, Plant/drug effects , Germination/drug effects , Germination/genetics , Isoenzymes/genetics , Molecular Sequence Data , Mutant Proteins/genetics , Sequence Homology, Amino Acid , Signal Transduction/drug effects , Signal Transduction/genetics , Sodium Chloride/pharmacology , Stress, Physiological/drug effects , Stress, Physiological/geneticsABSTRACT
A casein kinase 1 protein gene, CK1A, was isolated from Arabidopsis seedlings by RT-PCR method. This gene contains an open reading frame of 2,112 bp, which encodes 703 amino acids. The plant expression vector of 35S: GFP: CK1A was constructed by the Gateway System. The 35S: GFP: CK1A fusion protein was localized to the nucleus in onion epidermal cell, indicating that the product of CK1A gene plays a role in the cell nucleus. The semi-quantitative RT-PCR analysis showed that CK1A was highly expressed in flowers, stems and roots, but less in leaves and leafstalks. The yeast two-hybrid analysis demonstrated that CK1A and CRY2 can interact in vivo under blue light, which indicates that CK1A may play an important role in blue light signal induction of Arabidopsis.
