Cookies on this website
We use cookies to ensure that we give you the best experience on our website. If you click 'Continue' we'll assume that you are happy to receive all cookies and you won't see this message again. Click 'Find out more' for information on how to change your cookie settings.

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 (PHT1) proteins are the H(+) /Pi symporters that carry out Pi uptake in angiosperms. PHT1 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 mRNAs 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 PHT1 proteins, respectively - from their streptophyte algal ancestor. Both systems operate in parallel in extant early diverging land plants.

Original publication

DOI

10.1111/nph.14431

Type

Journal article

Journal

New Phytol

Publication Date

05/2017

Volume

214

Pages

1158 - 1171

Keywords

Coleochaete nitellarum, Marchantia polymorpha, PTB Pi transporters, Pi uptake, early diverging land plants, streptophyte algae