Expression of a CO2-permeable aquaporin enhances mesophyll conductance in the C4 species setaria viridis

Maria Ermakova; Hannah Osborn; Michael Groszmann; Soumi Bala; Andrew Bowerman; Samantha McGaughey; Caitlin Byrt; Hugo Alonso-Cantabrana; Steve Tyerman; Robert T. Furbank; Robert E. Sharwood; Caemmerer Von

doi:10.7554/eLife.70095

Expression of a CO2-permeable aquaporin enhances mesophyll conductance in the C4 species setaria viridis

Maria Ermakova, Hannah Osborn, Michael Groszmann, Soumi Bala, Andrew Bowerman, Samantha McGaughey, Caitlin Byrt, Hugo Alonso-Cantabrana, Steve Tyerman, Robert T. Furbank, Robert E. Sharwood, Caemmerer Von

Western Sydney University

Research output: Contribution to journal › Article › peer-review

Abstract

A fundamental limitation of photosynthetic carbon fixation is the availability of CO2. In C4 plants, primary carboxylation occurs in mesophyll cytosol, and little is known about the role of CO2 diffusion in facilitating C4 photosynthesis. We have examined the expression, localization, and functional role of selected plasma membrane intrinsic aquaporins (PIPs) from Setaria italica (foxtail millet) and discovered that SiPIP2;7 is CO2-permeable. When ectopically expressed in mesophyll cells of S. viridis (green foxtail), SiPIP2;7 was localized to the plasma membrane and caused no marked changes in leaf biochemistry. Gas-exchange and C18O16O discrimination measurements revealed that targeted expression of SiPIP2;7 enhanced the conductance to CO2 diffusion from the intercellular airspace to the mesophyll cytosol. Our results demonstrate that mesophyll conductance limits C4 photosynthesis at low pCO2 and that SiPIP2;7 is a functional CO2 permeable aquaporin that can improve CO2 diffusion at the airspace/mesophyll interface and enhance C4 photosynthesis.

Original language	English
Article number	e70095
Number of pages	16
Journal	eLife
Volume	10
DOIs	https://doi.org/10.7554/eLife.70095
Publication status	Published - 2021

Open Access - Access Right Statement

Copyright Ermakova et al. This article is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use and redistribution provided that the original author and source are credited.

Access to Document

10.7554/eLife.70095

Cite this

@article{ead4baa55899470c8e686f07fbc3826b,

title = "Expression of a CO2-permeable aquaporin enhances mesophyll conductance in the C4 species setaria viridis",

abstract = "A fundamental limitation of photosynthetic carbon fixation is the availability of CO2. In C4 plants, primary carboxylation occurs in mesophyll cytosol, and little is known about the role of CO2 diffusion in facilitating C4 photosynthesis. We have examined the expression, localization, and functional role of selected plasma membrane intrinsic aquaporins (PIPs) from Setaria italica (foxtail millet) and discovered that SiPIP2;7 is CO2-permeable. When ectopically expressed in mesophyll cells of S. viridis (green foxtail), SiPIP2;7 was localized to the plasma membrane and caused no marked changes in leaf biochemistry. Gas-exchange and C18O16O discrimination measurements revealed that targeted expression of SiPIP2;7 enhanced the conductance to CO2 diffusion from the intercellular airspace to the mesophyll cytosol. Our results demonstrate that mesophyll conductance limits C4 photosynthesis at low pCO2 and that SiPIP2;7 is a functional CO2 permeable aquaporin that can improve CO2 diffusion at the airspace/mesophyll interface and enhance C4 photosynthesis.",

author = "Maria Ermakova and Hannah Osborn and Michael Groszmann and Soumi Bala and Andrew Bowerman and Samantha McGaughey and Caitlin Byrt and Hugo Alonso-Cantabrana and Steve Tyerman and Furbank, {Robert T.} and Sharwood, {Robert E.} and Caemmerer Von",

year = "2021",

doi = "10.7554/eLife.70095",

language = "English",

volume = "10",

journal = "eLife",

issn = "2050-084X",

publisher = "eLife Sciences Publications ",

}

TY - JOUR

T1 - Expression of a CO2-permeable aquaporin enhances mesophyll conductance in the C4 species setaria viridis

AU - Ermakova, Maria

AU - Osborn, Hannah

AU - Groszmann, Michael

AU - Bala, Soumi

AU - Bowerman, Andrew

AU - McGaughey, Samantha

AU - Byrt, Caitlin

AU - Alonso-Cantabrana, Hugo

AU - Tyerman, Steve

AU - Furbank, Robert T.

AU - Sharwood, Robert E.

AU - Von, Caemmerer

PY - 2021

Y1 - 2021

N2 - A fundamental limitation of photosynthetic carbon fixation is the availability of CO2. In C4 plants, primary carboxylation occurs in mesophyll cytosol, and little is known about the role of CO2 diffusion in facilitating C4 photosynthesis. We have examined the expression, localization, and functional role of selected plasma membrane intrinsic aquaporins (PIPs) from Setaria italica (foxtail millet) and discovered that SiPIP2;7 is CO2-permeable. When ectopically expressed in mesophyll cells of S. viridis (green foxtail), SiPIP2;7 was localized to the plasma membrane and caused no marked changes in leaf biochemistry. Gas-exchange and C18O16O discrimination measurements revealed that targeted expression of SiPIP2;7 enhanced the conductance to CO2 diffusion from the intercellular airspace to the mesophyll cytosol. Our results demonstrate that mesophyll conductance limits C4 photosynthesis at low pCO2 and that SiPIP2;7 is a functional CO2 permeable aquaporin that can improve CO2 diffusion at the airspace/mesophyll interface and enhance C4 photosynthesis.

AB - A fundamental limitation of photosynthetic carbon fixation is the availability of CO2. In C4 plants, primary carboxylation occurs in mesophyll cytosol, and little is known about the role of CO2 diffusion in facilitating C4 photosynthesis. We have examined the expression, localization, and functional role of selected plasma membrane intrinsic aquaporins (PIPs) from Setaria italica (foxtail millet) and discovered that SiPIP2;7 is CO2-permeable. When ectopically expressed in mesophyll cells of S. viridis (green foxtail), SiPIP2;7 was localized to the plasma membrane and caused no marked changes in leaf biochemistry. Gas-exchange and C18O16O discrimination measurements revealed that targeted expression of SiPIP2;7 enhanced the conductance to CO2 diffusion from the intercellular airspace to the mesophyll cytosol. Our results demonstrate that mesophyll conductance limits C4 photosynthesis at low pCO2 and that SiPIP2;7 is a functional CO2 permeable aquaporin that can improve CO2 diffusion at the airspace/mesophyll interface and enhance C4 photosynthesis.

UR - https://hdl.handle.net/1959.7/uws:65563

U2 - 10.7554/eLife.70095

DO - 10.7554/eLife.70095

M3 - Article

SN - 2050-084X

VL - 10

JO - eLife

JF - eLife

M1 - e70095

ER -

Expression of a CO2-permeable aquaporin enhances mesophyll conductance in the C4 species setaria viridis

Abstract

Open Access - Access Right Statement

Access to Document

Other files and links

Fingerprint

Cite this