Golgi-localized mannanases sustain hemicellulose biosynthesis.
Jacobson T, Edwards M, Qiande M, Robert M, Moncrieff J
Cell Wall Biology
Understanding how plants build their cell walls could lead to crops with improved seeds, better food textures, and plants engineered to store more carbon — benefits that touch everything from the food on your plate to efforts to fight climate change.
Plants build their cell walls partly from a type of sugar chain called mannan, which gives structure to seeds and other tissues. Researchers found that two enzymes long believed to only break these chains apart outside the cell are actually working inside the cell to help build them in the first place. This surprising double role means scientists may have been missing a key piece of the puzzle when trying to engineer plants with stronger or more useful cell walls.
Key Findings
Two mannan-degrading enzymes (MAN2 and MAN5) were found to operate inside the Golgi apparatus — the cell's internal assembly factory — rather than only outside the cell as previously assumed.
Arabidopsis plants lacking both MAN2 and MAN5 produced seeds that looked like mutants unable to make mannan at all, linking these 'degrading' enzymes directly to mannan production.
In yeast experiments, intracellular MAN2 and MAN5 converted insoluble mannan into water-soluble forms, suggesting they help keep the biosynthesis process flowing by preventing clogging with insoluble material.
chevron_right Technical Summary
Scientists discovered that certain enzymes inside plant cells — previously thought only to break down cell wall sugars outside the cell — actually help build those same sugars in the first place. This finding reveals a hidden step in how plants construct their cell walls, which could unlock new ways to engineer stronger or more useful plant materials.
Abstract Preview
Mannans with β-1,4-linked backbones are common cell wall components of algae and land plants. Prior challenges to enhance β-mannan content in plants point to unclear metabolic bottlenecks and the p...
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