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Andriotis, Vasilios M. E., Rejzek, Martin, Barclay, Elaine, Rugen, Michael D., Field, Robert A. 
ORCID: https://orcid.org/0000-0001-8574-0275 and Smith, Alison M.
(2016)
Cell wall degradation is required for normal starch mobilisation in barley endosperm.
Scientific Reports, 6.
ISSN 2045-2322
Abstract
Starch degradation in barley endosperm provides carbon for early seedling growth, but the control of this process is poorly understood. We investigated whether endosperm cell wall degradation is an important determinant of the rate of starch degradation. We identified iminosugar inhibitors of enzymes that degrade the cell wall component arabinoxylan. The iminosugar 1,4-dideoxy-1, 4-imino-l-arabinitol (LAB) inhibits arabinoxylan arabinofuranohydrolase (AXAH) but does not inhibit the main starch-degrading enzymes α- and β-amylase and limit dextrinase. AXAH activity in the endosperm appears soon after the onset of germination and resides in dimers putatively containing two isoforms, AXAH1 and AXAH2. Upon grain imbibition, mobilisation of arabinoxylan and starch spreads across the endosperm from the aleurone towards the crease. The front of arabinoxylan degradation precedes that of starch degradation. Incubation of grains with LAB decreases the rate of loss of both arabinoxylan and starch, and retards the spread of both degradation processes across the endosperm. We propose that starch degradation in the endosperm is dependent on cell wall degradation, which permeabilises the walls and thus permits rapid diffusion of amylolytic enzymes. AXAH may be of particular importance in this respect. These results provide new insights into the mobilization of endosperm reserves to support early seedling growth.
| Item Type: | Article |
|---|---|
| Additional Information: | Funding Information: This research was funded by the Biotechnology and Biological Sciences Research Council (BBSRC, UK) Crop Improvement Research Club through grant BB/I017291/1 to AMS and RAF, by a BBSRC PhD studentship BB/ J500069/1 to MDR and by a BBSRC Institute Strategic Programme Grant BB/J004561/1 to the John Innes Centre. |
| Uncontrolled Keywords: | general ,/dk/atira/pure/subjectarea/asjc/1000 |
| Faculty \ School: | Faculty of Science > School of Chemistry, Pharmacy and Pharmacology Faculty of Science > School of Biological Sciences |
| Related URLs: | |
| Depositing User: | LivePure Connector |
| Date Deposited: | 04 Sep 2024 13:34 |
| Last Modified: | 02 Oct 2024 09:30 |
| URI: | https://ueaeprints.uea.ac.uk/id/eprint/96526 |
| DOI: | 10.1038/srep33215 |
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