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Westgeest AJ, Dauzat M, Simonneau T, Pantin F. Leaf starch metabolism sets the phase of stomatal rhythm. THE PLANT CELL 2023; 35:3444-3469. [PMID: 37260348 PMCID: PMC10473205 DOI: 10.1093/plcell/koad158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 04/25/2023] [Accepted: 05/15/2023] [Indexed: 06/02/2023]
Abstract
In leaves of C3 and C4 plants, stomata open during the day to favor CO2 entry for photosynthesis and close at night to prevent inefficient transpiration of water vapor. The circadian clock paces rhythmic stomatal movements throughout the diel (24-h) cycle. Leaf transitory starch is also thought to regulate the diel stomatal movements, yet the underlying mechanisms across time (key moments) and space (relevant leaf tissues) remain elusive. Here, we developed PhenoLeaks, a pipeline to analyze the diel dynamics of transpiration, and used it to screen a series of Arabidopsis (Arabidopsis thaliana) mutants impaired in starch metabolism. We detected a sinusoidal, endogenous rhythm of transpiration that overarches days and nights. We determined that a number of severe mutations in starch metabolism affect the endogenous rhythm through a phase shift, resulting in delayed stomatal movements throughout the daytime and diminished stomatal preopening during the night. Nevertheless, analysis of tissue-specific mutations revealed that neither guard-cell nor mesophyll-cell starch metabolisms are strictly required for normal diel patterns of transpiration. We propose that leaf starch influences the timing of transpiration rhythm through an interplay between the circadian clock and sugars across tissues, while the energetic effect of starch-derived sugars is usually nonlimiting for endogenous stomatal movements.
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Affiliation(s)
| | - Myriam Dauzat
- LEPSE, Univ Montpellier, INRAE, Institut Agro, Montpellier, France
| | | | - Florent Pantin
- LEPSE, Univ Montpellier, INRAE, Institut Agro, Montpellier, France
- Univ Angers, Institut Agro, INRAE, IRHS, SFR QUASAV, Angers F-49000, France
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Isner JC, Olteanu VA, Hetherington AJ, Coupel-Ledru A, Sun P, Pridgeon AJ, Jones GS, Oates M, Williams TA, Maathuis FJM, Kift R, Webb AR, Gough J, Franklin KA, Hetherington AM. Short- and Long-Term Effects of UVA on Arabidopsis Are Mediated by a Novel cGMP Phosphodiesterase. Curr Biol 2019; 29:2580-2585.e4. [PMID: 31353185 PMCID: PMC6692503 DOI: 10.1016/j.cub.2019.06.071] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Revised: 06/05/2019] [Accepted: 06/24/2019] [Indexed: 12/21/2022]
Abstract
Although UVA radiation (315-400 nm) represents 95% of the UV radiation reaching the earth's surface, surprisingly little is known about its effects on plants [1]. We show that in Arabidopsis, short-term exposure to UVA inhibits the opening of stomata, and this requires a reduction in the cytosolic level of cGMP. This process is independent of UVR8, the UVB receptor. A cGMP-activated phosphodiesterase (AtCN-PDE1) was responsible for the UVA-induced decrease in cGMP in Arabidopsis. AtCN-PDE1-like proteins form a clade within the large HD-domain/PDEase-like protein superfamily, but no eukaryotic members of this subfamily have been functionally characterized. These genes have been lost from the genomes of metazoans but are otherwise conserved as single-copy genes across the tree of life. In longer-term experiments, UVA radiation increased growth and decreased water-use efficiency. These experiments revealed that PDE1 is also a negative regulator of growth. As the PDE1 gene is ancient and not represented in animal lineages, it is likely that at least one element of cGMP signaling in plants has evolved differently to the system present in metazoans.
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Affiliation(s)
- Jean-Charles Isner
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TH, UK
| | - Vlad-Aris Olteanu
- Department of Computer Science, Merchant Venturers Building, University of Bristol, Woodland Road, Bristol BS8 1UB, UK
| | | | - Aude Coupel-Ledru
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TH, UK
| | - Peng Sun
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TH, UK
| | - Ashley J Pridgeon
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TH, UK
| | - Glyndyr S Jones
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TH, UK
| | - Matthew Oates
- Department of Computer Science, Merchant Venturers Building, University of Bristol, Woodland Road, Bristol BS8 1UB, UK
| | - Tom A Williams
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TH, UK
| | | | - Richard Kift
- School of Earth and Environmental Sciences, University of Manchester, Simon Building, Oxford Road, Manchester M13 9PL, UK
| | - Ann R Webb
- School of Earth and Environmental Sciences, University of Manchester, Simon Building, Oxford Road, Manchester M13 9PL, UK
| | - Julian Gough
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QU, UK
| | - Keara A Franklin
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TH, UK
| | - Alistair M Hetherington
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TH, UK.
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