Abstract
Stomata of plant leaves open to enable CO2 entry for photosynthesis and close to reduce water loss via transpiration. Compared with photosynthesis, stomata respond slowly to fluctuating light, reducing assimilation and water use efficiency. Efficiency gains are possible without a cost to photosynthesis if stomatal kinetics can be accelerated. Here we show that clustering of the GORK channel, which mediates K+ efflux for stomatal closure in the model plant Arabidopsis, arises from binding between the channel voltage sensors, creating an extended ‘sensory antenna’ for channel gating. Mutants altered in clustering affect channel gating to facilitate K+ flux, accelerate stomatal movements and reduce water use without a loss in biomass. Our findings identify the mechanism coupling channel clustering with gating, and they demonstrate the potential for engineering of ion channels native to the guard cell to enhance stomatal kinetics and improve water use efficiency without a cost in carbon fixation.
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Data availability
Data generated and analysed during this study are included in the article, its supplementary information files, and are also available on reasonable request to the corresponding author. Source data are provided with this paper.
Code availability
The OnGuard3 platform and the model parameter sets are freely available to academic users and may be downloaded from www.psrg.org.uk.
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Acknowledgements
This work was supported by BBSRC grants BB/L001276/1, BB/L019205/1, BB/M001601/1 and BB/ T013508/1 to M.R.B., by a Royal Thai PhD studentship to W.H., a University of Glasgow Doctoral Training Studentship to W.C., a Lord Kelvin-Adam Smith Doctoral Fellowship to F.A.L.S.-A. and BBSRC grant BB/R019894/1 to A.A. We thank N. Donald for support in mbSUS assays and A. Ruiz-Pardo for help in plant maintenance.
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M.R.B. conceived the work and developed the strategies for analysis with B.Z., J.C.A. and A.H.; W.H., W.C. and B.Z. carried out and analysed the mbSUS assays; W.H. carried out oocyte electrophyiology and, with J.C.A., M.K. and M.R.B., the confocal, gas exchange and growth studies; M.K. carried out the guard cell electrophysiology and analysed the results with M.R.B.; S.W. expressed and purified the channel N-termini and carried out the gel filtration studies; M.P. and A.A. undertook the hydroponic growth studies; M.R.B. carried out the modelling with A.H., J.C.A., W.H., F.A.L.S.-A. and M.K.; M.R.B. wrote the manuscript, and all authors edited and approved the manuscript.
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Horaruang, W., Klejchová, M., Carroll, W. et al. Engineering a K+ channel ‘sensory antenna’ enhances stomatal kinetics, water use efficiency and photosynthesis. Nat. Plants 8, 1262–1274 (2022). https://doi.org/10.1038/s41477-022-01255-2
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DOI: https://doi.org/10.1038/s41477-022-01255-2