Identification and characterization of a second plasma membrane H super(+)-ATPase gene subfamily in Nicotiana plumbaginifolia

A cDNA clone was isolated for a fourth pma gene encoding a putative plasma membrane H super(+)-ATPase of Nicotiana plumbaginifolia). The sequence of the predicted 952 residue PMA4 polypeptide was compared with those of other known plant PMAs, revealing a higher identity with the Arabidopsis thaliana proteins (86-89%) than with the other three N. plumbaginifolia PMA proteins (80-82%). This supports the view that there are two pma subfamilies which probably arose from a gene duplication predating the separation of the Dilleniidae and Asteridae plant subclasses.