Aeluropus littoralis NaCl-induced vacuolar H(+)-ATPase subunit c: molecular cloning and expression analysis.

The vacuolar H(+)-ATPase (VHA) is a universal component of eukaryotic organisms that is responsible for establishing and maintaining intracellular pH gradients across specialized organellar membranes, and influences the transport of cations into the vacuoles of plant cells. A cDNA clone (AlVHA-c) encoding the c subunit of V-ATPase was isolated from the monocot halophyte Aeluropus littoralis. The DNA sequence of AlVHA-c showed significant homology with V-ATPase subunit c of millet, rice and Zea mays. The deduced amino acid sequence of AlVHA-c and other reported c subunits were compared, and sequence relationships have been drawn to know their genetic relatedness. Semi-quantitative RT-PCR analysis of salt-treated A. littoralis plants revealed that subunit c of V-ATPase is regulated by NaCl treatment at transcriptional level in a tissue-specific manner. The increased V-ATPase subunits amounts of A. littoralis provide the energy for the compartmentalization of sodium in response to salinity.