Cloning, Characterization and Expression Analysis of a Cytosolic Ascorbate Peroxidase Gene from Grimmia Pilifera

摘要

Ascorbate peroxidase(APX) is a class I peroxidase that catalyzed the conversion of H_2O_2 to H_2O and O_2 using ascorbate as the specific electron donor. This enzyme has a key function in scavenging reactive oxygen species (ROS) and the protection against toxic effects of ROS in plants. Here we reported the identification of an APX gene from a cDNA library of Grimmia pilifera. The full-length of the gene was cloned by 3'-RACE approach, and named as GpAPX. The predicted proteins of GpAPX consisted of 256 amino acid residues with a calculated molecular mass of 28.2 kDa, and displayed high similarity to other plant proteins. It also contains three conserved domains and two signatures. QRT-PCR analysis suggested that the expression of GpAPX gene was induced in both dehydration and rehydration. Its expression level increased under drought stress, inhibited at the begining of re-watering, and peaked on 12h after re-watering. The results demonstrated that the expression of GpAPX gene closely related to dehydration and rehydration, and its isolation established a good foundation for further study on the resistance of Grimmia pilifera to drought stress.