Arabidopsis Sucrose Synthase 3 (SUS3) regulates starch accumulation in guard cells at the end of day
Open access
Date
2023Type
- Journal Article
ETH Bibliography
yes
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Abstract
Starch in the stomatal guard cells is largely synthesized using carbon precursors originating from sugars imported from the leaf mesophyll. Such heterotrophic nature of guard cell starch synthesis prompted us to investigate the role of cytosolic sucrose synthases (SUS) in this pathway. Out of the six members of the Arabidopsis SUS gene family, SUS3 was the most highly expressed isoform in guard cells. The Arabidopsis sus3 mutant displayed changes in guard cell starch contents comparable to the Wild Type (WT) up until 6 h into the day. After this time point, sus3 guard cells surprisingly started to accumulate starch at very high rates, reaching the end of the day with significantly more starch than WT. Based on the phenotype of the sus3 mutant, we suggest that in guard cells, SUS3 is involved in the regulation of carbon fluxes towards starch synthesis during the second half of the day. SUS3 may be part of a previously predicted guard cell futile cycle of metabolic reactions, in which sucrose is re-synthesized from UDP-glucose to avoid excessive starch synthesis toward the end of the day. This is in contrast to typical storage organs, in which cytosolic SUS is required to produce ADP-glucose for starch synthesis. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000602758Publication status
publishedExternal links
Journal / series
Plant Signaling & BehaviorVolume
Pages / Article No.
Publisher
Landes BioscienceSubject
starch; stomatal movements; sucrose synthase; guard cellsOrganisational unit
03706 - Widmer, Alexander / Widmer, Alexander
08715 - Gruppe Mol. Physiologie der Pflanzen / Plant Molecular Physiology Group
Funding
166539 - Mechanistic insights into the adaptive plasticity of plant starch metabolism (SNF)
185241 - Rewiring starch metabolism for plant environmental adaptation (SNF)
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ETH Bibliography
yes
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