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Updated: Nov 12, 2025
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Pulse-chase Analysis of N-linked Sugar Chains from Glycoproteins in Mammalian Cells
Published on: April 27, 2010
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The nucellus: between cell elimination and sugar transport.
Jing Lu1,2, Rozenn Le Hir1, Dennys-Marcela Gómez-Páez1
1Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, CNRS, University of Paris-Saclay, Route de St-Cyr (RD10), 78026 Versailles Cedex, France.
Plant Physiology
|March 15, 2021
Summary
The study reveals that the nucellus in Arabidopsis seeds acts as both a sugar source and sink, supplying nutrients to the endosperm via SWEET4 during its elimination. This uncovers a novel sugar transport pathway crucial for seed development.
Area of Science:
- Plant biology
- Developmental biology
- Molecular genetics
Background:
- Seed architecture is determined by tissue and nutrient partitioning.
- In angiosperms, the nucellus and endosperm exhibit antagonistic development, with the endosperm acting as the primary sugar sink.
- Arabidopsis endosperm partially eliminates the nucellus and imports sugars from the seed coat.
Purpose of the Study:
- To investigate the role of the nucellus in nutrient partitioning during seed development in Arabidopsis.
- To elucidate the sugar transport pathway and its coordination with nucellus cell elimination.
Main Methods:
- Symplasmic connection analysis between nucellus and chalaza.
- Investigation of starch accumulation and release in the transient nucellus.
- Analysis of sugar export via the SWEET4 facilitator.
- Study of the transparent testa 16 (tt16) mutant affecting nucellus elimination.
Main Results:
- The nucellus is symplasmically connected to the chalaza and functions as both a sugar sink and source.
- The transient nucellus accumulates starch and releases it apoplasmically during elimination.
- The persistent nucellus exports sugars to the endosperm through SWEET4.
- Analysis of the tt16 mutant revealed coordination between nutrient partitioning and nucellus cell elimination.
Conclusions:
- A novel sugar transport pathway in Arabidopsis seeds is identified, involving the nucellus.
- Sugar redistribution is intrinsically linked to the nucellus cell-elimination program.
- This study provides insights into the ancient mechanisms shaping seed architecture and nutrient allocation.
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