Characterization of Five Phosphoenolpyruvate Carboxylase Genes of Rice

Abstract

A survey of the complete nucleotide sequence of the rice genome revealed the presence of five genes that encode phosphoenolpyruvate carboxylase (PEPC), four (Osppc1-4) of which encode the plant-type PEPC while one (Osppc-b) the bacterial-type. The plant-type genes have homologous exon-intron structures, an indication of their evolution from a common ancestor gene. Expression of each Osppc gene was analyzed by RT-PCR. The results indicate that expression of Osppc1, Osppc3 and Osppc-b was very low in all organ tested, while Osppc2 and Osppc4 were highly expressed in green organs. It was also found that expression of Osppc2 in leaf blade showed diurnal variation while that of Osppc4 was constitutive. Expression analyses of Osppc2 and Osppc4 using the reporter gene are now in progress.