Tag: Christie J. M.

The potential of enhancing stomatal kinetics to improve water use efficiency without penalty in carbon fixation

Optogenetic manipulation of stomatal kinetics improves carbon assimilation, water use, and growth

by Papanatsiou M., Petersen J., Henderson L., Wang Y., Christie J. M., Blatt M. R. (2019)

  1. M. Papanatsiou1,2, 
  2. J. Petersen2,*, 
  3. L. Henderson2, 
  4. Y. Wang1,3, 
  5. J. M. Christie2,†,‡, 
  6. M. R. Blatt1,2,3,†,‡

  1. Laboratory of Plant Physiology and Biophysics, Institute of Molecular, Cell and Systems Biology, University of Glasgow, University Avenue, Glasgow G12 8QQ, UK.
  2. Plant Science Group, Institute of Molecular, Cell and Systems Biology, University of Glasgow, University Avenue, Glasgow G12 8QQ, UK.
  3. Institute of Crop Science, College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, Hangzhou 310058, China.

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In Science 363, Issue 6434, 1456-1459 – DOI: 10.1126/science.aaw0046 –

http://science.sciencemag.org/content/363/6434/1456

Speeding up stomatal responses

A plant’s cellular metabolism rapidly adjusts to changes in light conditions, but its stomata—pores that allow gas exchange in leaves—are slower to respond. Because of the lagging response, photosynthesis is less efficient, and excess water is lost through the open pores. Papanatsiou et al. introduced a blue light–responsive ion channel into stomata of the small mustard plant Arabidopsis. The channel increased the rate of stomata opening and closing in response to light. The engineered plants produced more biomass, especially in the fluctuating light conditions typical of outdoor growth.

Abstract

Stomata serve dual and often conflicting roles, facilitating carbon dioxide influx into the plant leaf for photosynthesis and restricting water efflux via transpiration. Strategies for reducing transpiration without incurring a cost for photosynthesis must circumvent this inherent coupling of carbon dioxide and water vapor diffusion.

We expressed the synthetic, light-gated K+ channel BLINK1 in guard cells surrounding stomatal pores in Arabidopsis to enhance the solute fluxes that drive stomatal aperture.

BLINK1 introduced a K+conductance and accelerated both stomatal opening under light exposure and closing after irradiation. Integrated over the growth period, BLINK1 drove a 2.2-fold increase in biomass in fluctuating light without cost in water use by the plant.

Thus, we demonstrate the potential of enhancing stomatal kinetics to improve water use efficiency without penalty in carbon fixation.


BLUS1 functions as a phototropin substrate and primary regulator of stomatal control

 

Phosphorylation of BLUS1 kinase by phototropins is a primary step in stomatal opening

by Takemiya A., Sugiyama N., Fujimoto H., Tsutsumi T., Yamauchi S., Hiyama A., Tada Y., Christie J. M., Shimazaki K.-i. (2013)

in Nature Communications 4 – doi:10.1038/ncomms3094  –

Medline – http://www.nature.com/ncomms/2013/130628/ncomms3094/full/ncomms3094.html – 

https://www.nature.com/articles/ncomms3094

Abstract

Opening of stomata in the plant facilitates photosynthetic CO2 fixation and transpiration. Blue-light perception by phototropins (phot1, phot2) activates the plasma membrane H+-ATPase, causing stomata to open.

Here we describe a regulator that connects these components, a Ser/Thr protein kinase, BLUS1 (BLUE LIGHT SIGNALING1), which mediates a primary step for phototropin signalling in guard cells.

blus1 mutants identified by infrared thermography result in a loss of blue light-dependent stomatal opening. BLUS1 encodes a protein kinase that is directly phosphorylated by phot1 in vitro and in vivo at Ser-348 within its C-terminus. Both phosphorylation of Ser-348 and BLUS1 kinase activity are essential for activation of the H+-ATPase.

blus1 mutants show lower stomatal conductance and CO2 assimilation than wild-type plants under decreased ambient CO2.

Together, our analyses demonstrate that BLUS1 functions as a phototropin substrate and primary regulator of stomatal control to enhance photosynthetic CO2assimilation under natural light conditions.