Proteomic analysis of phosphoproteins regulated by abscisic acid in rice leaves.

Abscisic acid (ABA) is a hormone that regulates plant development and adaptation to environmental stresses. Protein phosphorylation has been recognized as an important mechanism for ABA signaling. However, the target phosphoproteins regulated by ABA are still largely unknown. Here, we report the identification of ABA-regulated phosphoproteins in rice using proteomic approaches. Six ABA-regulated phosphoproteins were identified as G protein beta subunit-like protein, ascorbate peroxidase, manganese superoxide dismutase, triosephosphate isomerase, putative Ca(2+)/H(+) antiporter regulator protein, and glyoxysomal malate dehydrogenase. These results provide new insight into the regulatory mechanism for some ABA signaling proteins and implicate several previously unrecognized proteins in ABA action.