Identification of a cDNA encoding Ascorbate peroxidase from Pinus Pinaster Ait.

Abstract

The maritime or wild pine (Pinus pinaster Ait.) is the conifer with the widest distribution in Portugal, being of an extreme economic importance to wood and paper industries and also as a large source of pitch, turpentine and resin. Pine forest decay is largely associated with abiotic and biotic stresses, which ultimately leads to excessive production of reactive oxygen species (ROS), thus resulting in damage at the cellular level. Antioxidants and antioxidative enzymes are referred to have a role in the interruption of uncontrolled oxidation cascades occurring in different cell compartments. Ascorbate peroxidase (APX) exists as several isoforms that play an important role in the scavenging of H2O2 in higher plants, preventing not only cellular damage but also the inhibition of cytosolic and chloroplastic enzyme activity. The identification of cDNAs encoding ascorbate peroxidase isoenzymes was attempted by screening a Pinus pinaster cDNA library with homologous probes previously obtained by PCR amplification of cDNA using degenerated primers. A full cDNA sequence was obtained and the sequence analysis revealed high similarity with cytosolic soluble APX from higher plants. This cDNA will be used in genetic expression profilings.