Most higher plants have a number of different isozymes of peroxidase.
The presence of the large number of potential substrates and many isozymes makes it difficult to understand the role of each isozyme in vivo. We have already reported isolation and characterization of two cDNAs, designated prxRPA and prxRPN, encoding peroxidases from rice shoots. RNA blot hybridization revealed that both mRNAs accumulate at high levels in roots but only at low levels in shoots. However, levels of both mRNAs in shoots were dramatically stimulated by wounding and ethephon treatment. Restriction maps of two positive clones were identical.