The photosynthetic response of tobacco plants overexpressing ice plant aquaporin McMIPB to a soil water deficit and high vapor pressure deficit

Miki Kawase,Yuko T Hanba,Maki Katsuhara

doi:10.1007/s10265-013-0548-4

Miki Kawase, Yuko T Hanba + Show 1 more

Open Access

https://doi.org/10.1007/s10265-013-0548-4

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Abstract

We investigated the photosynthetic capacity and plant growth of tobacco plants overexpressing ice plant (Mesembryanthemum crystallinum L.) aquaporin McMIPB under (1) a well-watered growth condition, (2) a well-watered and temporal higher vapor pressure deficit (VPD) condition, and (3) a soil water deficit growth condition to investigate the effect of McMIPB on photosynthetic responses under moderate soil and atmospheric humidity and water deficit conditions. Transgenic plants showed a significantly higher photosynthesis rate (by 48 %), higher mesophyll conductance (by 52 %), and enhanced growth under the well-watered growth condition than those of control plants. Decreases in the photosynthesis rate and stomatal conductance from ambient to higher VPD were slightly higher in transgenic plants than those in control plants. When plants were grown under the soil water deficit condition, decreases in the photosynthesis rate and stomatal conductance were less significant in transgenic plants than those in control plants. McMIPB is likely to work as a CO2 transporter, as well as control the regulation of stomata to water deficits.

Highlights

IntroductionConductance in the liquid phase, which is across the cell wall, plasma membrane, cytosol, chloroplast envelope, and stroma, is important
We investigated the photosynthetic capacity and plant growth of tobacco plants overexpressing ice plant (Mesembryanthemum crystallinum L.) aquaporin McMIPB under (1) a well-watered growth condition, (2) a wellwatered and temporal higher vapor pressure deficit (VPD) condition, and (3) a soil water deficit growth condition to investigate the effect of McMIPB on photosynthetic responses under moderate soil and atmospheric humidity and water deficit conditions
When plants were grown under the soil water deficit condition, decreases in the photosynthesis rate and stomatal conductance were less significant in transgenic plants than those in control plants

Summary

Introduction

Conductance in the liquid phase, which is across the cell wall, plasma membrane, cytosol, chloroplast envelope, and stroma, is important. J Plant Res (2013) 126:517–527 conductance, the surface area of chloroplasts facing the intercellular air space, Sc, is important as the active area for CO2 diffusion to chloroplast stroma (Hanba et al 2004; Terashima et al 2006, 2011). Recent studies suggest that some plant aquaporins (water channel proteins that transport water molecules) in the plasma membrane and chloroplast envelope are CO2 transport candidates that reduce the diffusional resistance of CO2. Further studies are needed to investigate the role of aquaporin on CO2 diffusion in leaves

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