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Starch biosynthesis is crucial for maintaining photosynthesis and leaf growth under drought stress
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  • Hamada AbdElgawad,
  • Viktoriya Avramova,
  • Geert Baggerman,
  • Geert Van Raemdonck,
  • Dirk Valkenbog,
  • Xaveer Van Ostade,
  • Yves Guisez,
  • Els Prinsen,
  • Han Asard,
  • Wim Ende,
  • Gerrit Beemster
Hamada AbdElgawad
University of Antwerp
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Viktoriya Avramova
University of Antwerp
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Geert Baggerman
Flemish Institute for Technological Research
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Geert Van Raemdonck
University of Antwerp
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Dirk Valkenbog
University of Antwerp
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Xaveer Van Ostade
University of Antwerp
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Yves Guisez
University of Antwerp
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Els Prinsen
University of Antwerp
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Han Asard
University of Antwerp
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Wim Ende
KU Leuven
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Gerrit Beemster
University of Antwerp
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Abstract

To understand the growth response to drought, we performed a proteomics study in the leaf growth zone of maize (Zea mays L.) seedlings and functionally characterized the role of starch biosynthesis in the regulation of growth, photosynthesis and antioxidant capacity, using the shrunken2 mutant (sh2), defective in ADP-glucose pyrophosphorylase. Drought induced differential expression of 284 proteins overrepresented for photosynthesis, amino acids, sugar and starch metabolism, and redox-regulation. Changes in protein levels correlated with enzyme activities (increased ATP synthase, cysteine synthase, starch synthase, RuBisCo, peroxiredoxin, glutaredoxin, thioredoxin and decreased triosephosphate isomerase, ferredoxin, cellulose synthase activities, respectively) and metabolite concentrations (increased ATP, cysteine, glycine, serine, starch, proline and decreased cellulose levels). The sh2 mutant had a reduced ability to increase starch levels under drought conditions, causing soluble sugar starvation at the end of the night and impaired leaf growth. Increased RuBisCo activity and pigment concentrations observed in WT in response to drought were lacking in the mutant, which suffered more oxidative damage and recovered more slowly after re-watering. These results demonstrate that starch biosynthesis plays a crucial role in maintaining leaf growth under drought stress and facilitates enhanced carbon acquisition upon recovery.

Peer review status:UNDER REVIEW

20 Mar 2020Submitted to Plant, Cell & Environment
23 Mar 2020Submission Checks Completed
23 Mar 2020Assigned to Editor
24 Mar 2020Reviewer(s) Assigned
22 Apr 2020Review(s) Completed, Editorial Evaluation Pending
21 May 20201st Revision Received
22 May 2020Submission Checks Completed
22 May 2020Assigned to Editor
22 May 2020Review(s) Completed, Editorial Evaluation Pending