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The SOS1 transporter of Physcomitrella patens mediates sodium efflux in planta
Author(s) -
FraileEscanciano Ana,
Kamisugi Yasuko,
Cuming Andrew C.,
RodríguezNavarro Alonso,
Benito Begoña
Publication year - 2010
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2010.03405.x
Subject(s) - efflux , antiporter , physcomitrella patens , mutant , biology , biochemistry , membrane transport , chemistry , gene , membrane
Summary• SOS1 is an Na + /H + antiporter that plays a central role in Na + tolerance in land plants. SOS1 mediation of Na + efflux has been studied in plasma‐membrane vesicles and deduced from the SOS1 suppression of the Na + sensitivity of yeast mutants defective in Na + ‐efflux. However, SOS1‐mediated Na + efflux has not been characterized in either plant or yeast cells. Here, we use Physcomitrella patens to investigate the function of SOS1 in planta . • In P. patens , a nonvascular plant in which the study of ion cellular fluxes is technically simple, the existence of two SOS1 genes suggests that the Na + efflux remaining after the deletion of the ENA1 ATPase is mediated by a SOS1 system. Therefore, we cloned the P. patens SOS1 and SOS1B genes ( PpSOS1 and PpSOS1B , respectively) and complementary DNAs, and constructed the PpΔsos1 and PpΔena1/PpΔsos1 deletion lines by gene targeting. • Comparison of wild‐type, and PpΔsos1 and PpΔena1/PpΔsos1 mutant lines revealed that PpSOS1 is crucial for Na + efflux and that the PpΔsos1 line , and especially the PpΔena1/PpΔsos1 lines, showed excessive Na + accumulation and Na + ‐triggered cell death. The PpΔsos1 and PpΔena1/PpΔsos1 lines showed impaired high‐affinity K + uptake. • Our data support the hypothesis that PpSOS1 mediates cellular Na + efflux and that PpSOS1 enhances K + uptake by an indirect effect.