Expression of rice acyl-CoA oxidase isoenzymes in response to wounding.

To elucidate the role of acyl-CoA oxidase (ACX; EC 1.3.3.6) in plants, the expression patterns of rice ACXs in response to wounding were characterized. Three isogenes of ACX were identified in the rice genome. The deduced proteins of OsACX1, OsACX2 and OsACX3 consist of 669, 699 and 685 amino acid residues, respectively. The results from reverse transcriptase-PCR indicate that OsACX1 is expressed in leaves, stems, and roots, but was barely detectable in germinating seeds. OsACX2 was expressed predominantly in seeds. Only OsACX1 was upregulated by wounding, both locally and systemically. The expression of OsACX2 and OsACX3 remained unchanged. It is suggested that OsACX2 is involved in providing germinating seeds with sugar and energy, while OsACX1 plays a role in the synthesis of jasmonic acid in response to wounding.