Section 4
Chapter 3,852

Molecular cloning and characterization of a sodium-pump ATPase of the moss Physcomitrella patens

Benito, Bña.; Rodríguez-Navarro, A.

Plant Journal: for Cell and Molecular Biology 36(3): 382-389


ISSN/ISBN: 0960-7412
PMID: 14617094
DOI: 10.1046/j.1365-313x.2003.01883.x
Accession: 003851468

Physcomitrella patens grew slowly at 600 mm Na+, pH 6.0, affected by the low water potential but without signs of suffering Na+ toxicity. At pH 8.0, tolerance seemed to be lower but it grew at 200 mm Na+, again without signs of Na+ toxicity. The resistance of Physcomitrella cells to the toxic effects of Na+ can be accounted for by their capacity to keep high K+:Na+ ratios and to extrude Na+ by a system that is not dependent on DeltapH. Physcomitrella expresses two P-type ATPases similar in sequence to fungal ENA-type Na+-ATPases. A functional study in yeast demonstrated that one of these ATPases, PpENA1, is an Na+-pump. We also found that P. patens has a plant-type SOS1 Na+/H+ antiporter. We discuss that Na+-ATPases existed in early land plants but that they were lost during the evolution of bryophytes to flowering plants.

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