Molecular cloning and expression of a cDNA encoding cytosolic ascorbate peroxidase fromPimpinella brachycarpa

Ascorbate peroxidases (APX) detoxify hydrogen peroxide within the cytosol and chloroplasts of plant cells. In this report, the characterisation of a 997 bp cDNA clone encoding a cytosolic ascorbate peroxidase from Pimpinella brachycarpa, termed Pbapx, is described. Pbapx contains an open reading frame of 753 bp with strong homology to Fragaria ananassa, Capsicum annuum, and Nicotiana tabacum APX. Expression of Pbapx in E. coli cells was significantly increased upon IPTG induction. Furthermore, the Pbapx transcript was expressed in a variety of tissues by RT-PCR, showing that mRNA was detected at higher levels in embryogenic calli and roots, but lower in petioles and leaves. Based on these results, we suggest that this gene may regulate transcription for the development of embryogenic callus in Pimpinella brachycarpa