The ion pump, vacuolar H+-ATPase (V-ATPase) plays a major role in the maintenance of cellular pH, and influences the transport of cations into the vacuoles of plant cells. A cDNA clone (PcVHA-c1) encoding the c subunit of V- ATPase was isolated from the salt-tolerant wild rice, Porteresia coarctata. The DNA sequence of PcVHA-c1 showed significant homology with V-ATPase subunit c of rice. The deduced amino acid sequence of PcVHA-c1 and other reported c subunits were compared, and sequence relationships have been drawn to know their genetic relatedness. Southern analysis suggested the presence of multiple coding regions for subunit c in P. coarctata. Northern and Western analyses of
salt-treated P. coarctata plants revealed that subunit c of V-ATPase is upregulated by NaCl treatment at both transcriptional and translational level.