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Functional PTB phosphate transporters are present in streptophyte algae and early diverging land plants
Author(s) -
Bonnot Clémence,
Proust Hélène,
Pinson Benoît,
Colbalchini Florine P. L.,
LeslyVeillard Alexis,
Breuninger Holger,
Champion Clément,
Hetherington Alexander J.,
Kelly Steven,
Dolan Liam
Publication year - 2017
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/nph.14431
Subject(s) - biology , symporter , biochemistry , algae , transporter , botany , microbiology and biotechnology , gene
Summary Two inorganic phosphate (Pi) uptake mechanisms operate in streptophytes and chlorophytes, the two lineages of green plants. PHOSPHATE TRANSPORTER B ( PTB ) proteins are hypothesized to be the Na + /Pi symporters catalysing Pi uptake in chlorophytes, whereas PHOSPHATE TRANSPORTER 1 ( PHT 1) proteins are the H + /Pi symporters that carry out Pi uptake in angiosperms. PHT 1 proteins are present in all streptophyte lineages. However, Pi uptake in streptophyte algae and marine angiosperms requires Na + influx, suggesting that Na + /Pi symporters also function in some streptophytes. We tested the hypothesis that Na + /Pi symporters exist in streptophytes. We identified PTB sequences in streptophyte genomes. Core PTB proteins are present at the plasma membrane of the liverwort Marchantia polymorpha . The expression of M. polymorpha core PTB proteins in the Saccharomyces cerevisiae pho2 mutant defective in high‐affinity Pi transport rescues growth in low‐Pi environments. Moreover, levels of core PTB mRNA s of M. polymorpha and the streptophyte alga Coleochaete nitellarum are higher in low‐Pi than in Pi‐replete conditions, consistent with a role in Pi uptake from the environment. We conclude that land plants inherited two Pi uptake mechanisms – mediated by the PTB and PHT 1 proteins, respectively – from their streptophyte algal ancestor. Both systems operate in parallel in extant early diverging land plants.