Molecular characterization of pdc2 and mapping of three pdc genes from rice

The anaerobic fermentation pathway is thought to play an important role und er flooding conditions, The pyruvate decarboxylase 2 (pdc2) gene that encod es the first enzyme of this pathway has been cloned and characterized from rice. This gene has an open reading frame that putatively encodes a 603 ami no-acid-residue protein with a molecular mass of 64 kDa. pdc2 has five intr ons dispersed throughout the coding region, which is also true for rice pdc 1. Although the length of these introns in rice pdc2 are different from tho se in rice pdc1, they are located in exactly the same positions based on th e deduced amino-acid sequences. The temporal and spatial expression pattern s of pdc1 and pdc2 show that pdc2 is induced to a higher level during the e arly period (1.5-12 h) of anoxia than pdc1, which is induced more after lon ger time periods (24-72 h) of anoxia in both shoots and roots. The map posi tions of the three pde genes have also been determined. Rice pdc1 is locate d on chromosome 5 between BCD454A and RZ67, pdc2 is located on chromosome 3 between RZ329 and RZ313, and pdc3 is mapped on chromosome 7 distal to RG35 1.