AtPTP1, a Protein Tyrosine Phosphatase, is Involved in the ABA Signaling Pathway of the Seed Germination

Abstract

Seed germination has been known to require H₂O₂, but it remains unclear how the plant senses H₂O₂ to regulate germination. Since protein tyrosine phosphatase (PTPase) that is easily inactivated in oxidative state, we considered it as a candidate factor sensing H₂O₂ for the regulation of seed germination. To investigate the function of AtPTP1, a typical and single PTPase in Arabidopsis, in seed germination, we isolated T-DNA inserted mutants of AtPTP1 and generated the transgenic plants overexpressing the gene. The mutant seeds showed a higher germination frequency compared to wild-type seeds in a medium containing ABA, whereas the transgenic seeds showed delayed germination. Taking into account that recombinant AtPTP1 was inactivated by H₂O₂ and that ABA induces H₂O₂ generation, these results are considered to suggest that the AtPTP1 is involved in the ABA responses in seed germination.