Molecular cloning of a family of plant genes encoding a protein homologous to plasma membrane H+-translocating ATPases.

cDNA clones from Nicotiana plumbaginifolia have been isolated by hybridization to a yeast H+-ATPase gene. The largest one encodes a polypeptide (PMA2) of 956 amino acid residues which exhibits a homology of 73% with a limited protein sequence obtained from purified oat plasma membrane H+-ATPase (Schaller and Sussman, Plant Physiol. 86, 512-516, 1988) and an 82% homology with the Arabidopsis thaliana pma gene (Harper et al., Proc. Natl. Acad. Sci. USA 86, 1234-1238). It is therefore concluded that the N. plumbaginifolia pma2 gene encodes a plasma membrane H+-ATPase. Southern blot hybridization indicates that the plant pma2 gene belongs to a multigene family. Partial sequences of cDNA clones show that at least three pma genes are expressed in root cells.