Evidence of a role for tyrosine dephosphorylation in the control of postgermination arrest of development by abscisic acid in Arabidopsis thaliana L.

In the present paper evidence is presented indicating that tyrosine dephosphorylation is a key regulatory mechanism in postgermination arrest of Arabidopsis thaliana L. seed development mediated by abscisic acid (ABA). By using phenylarsine oxide (PAO), an inhibitor of tyrosine phosphatases, the sensitivity to the inhibitory effect of ABA on seed germination is enhanced. Consistent with this finding, we demonstrate that the ABA-responsive gene, RAB18, is hyperinduced in seeds imbibed in ABA plus PAO, compared with seeds imbibed only with ABA.