Glutathione Peroxidase cDNA Cloning and Expression in Soybean Roots under Heterodera glycines Infection

A gene named GmGPX1 encoding glutathione peroxidase (GPX) was cloned and sequenced from soybean roots infested Heterodera glycines by RT-PCR (Reverse Transcription PCR), which is a crucial enzyme in plant cells regulating reactive oxygen species (ROX). The cDNA length of cloned gene was 693bp, flanked by a 5'-untranslated region of 7bp and a 3'-untranslated region of 185bp, containing six exons and five introns. Genomic DNA fragment was located at Glycine max chromosome 5. The open reading frame of cDNA which encodes a polypeptide of 166 amino acid residues and protein molecular weight was 18375.8Da, theoretical isoelectric point 6.59. The deduced amino acid sequence showed about 99% and 64% homology with G max putative PHGPX (XP_003532707.1) and Arabidopsis thaliana GPX (NP_564813.1), respectively. The expression profile of the GmGPX1 in Xiaoliheidou (G. max) under H. glycines infection, which generates oxidative stress, was analyzed. Real time PCR analysis revealed that the GmGPX1 mRNA levels were increased stabilized from 1.3 to 1.47 times after exposure to H. glycines from 12h to 48h, and reduced to 1.07 times at 72h comparing with non-inoculation control. These results suggest that the GmGPX1 gene is induced by H. glycines at early stage in soybean roots and play an important role in removing oxidative damage.