Molecular cloning and characterization of a novel H+-translocating pyrophosphatase gene in Zea mays

A cDNA encoding a putative H+-translocating pyrophosphatase (H+-PPase) has been cloned from Zea mays by suppression subtractive hybridization (SSH) coupled with in silico cloning approach. The isolated 2974 bp full-length cDNA named ZmGPP contains a single 2400 bp open reading frame encoding a putative protein of 799 amino acids. The predicted protein has 16 transmembrane domains and is significantly similar to Golgi apparatus resident type-II H+-PPase from Arabidopsis thaliana. DNA gel blotting analysis shows that ZmGPP is a low-copy gene. Organ expression pattern analysis reveals that ZmGPPexpressed highly in leaf and tassel, followed by in stem, root, and ear. The Real-time RT-PCR assays showed that the expression of ZmGPP was up-regulated both in shoots and roots of maize seedlings under dehydration, cold and high salt stresses. Those results suggest that the ZmGPP product may play an important role in abiotic stress tolerance of Z. mays.