Effects of nitrogen nutrition on the synthesis and deposition of the ω-gliadins of wheat

A - Papers appearing in refereed journals

Wan, Y., Gritsch, C. S., Hawkesford, M. J. and Shewry, P. R. 2014. Effects of nitrogen nutrition on the synthesis and deposition of the ω-gliadins of wheat. Annals of Botany. 113, pp. 607-615.

AuthorsWan, Y., Gritsch, C. S., Hawkesford, M. J. and Shewry, P. R.
Abstract

Background and Aims
The ω-gliadin storage proteins of wheat are of interest in relation to their impact on grain processing properties and their role in food allergy, particularly the ω-5 sub-group and wheat-dependent exercise-induced anaphylaxis. The ω-gliadins are also known to be responsive to nitrogen application. This study therefore compares the effects of cultivar and nitrogen availability on the synthesis and deposition of ω-gliadins in wheat grown under field conditions in the UK, including temporal and spatial analyses at the protein and transcript levels.

Methods
SDS–PAGE, western blotting and N-terminal amino acid sequencing were used to compare the patterns of ω-gliadin components in mature grain of six British wheat (Triticum aestivum) cultivars and their accumulation during the development of grain grown in field plots with varying nitrogen supply. Changes in gene expression during development were determined using real-time reverse transcription–PCR (RT–PCR). Spatial patterns of gene expression and protein accumulation were determined by in situ hybridization and immunofluorescence microscopy, respectively.

Key Results
Two patterns of ω-gliadins were identified in the six cultivars, including both monomeric ‘gliadin’ proteins and subunits present in polymeric ‘glutenin’ fractions. Increasing the level of nitrogen fertilizer in field plots resulted in increased expression of ω-gliadin transcripts and increased proportions of ω-5 gliadins. Nitrogen supply also affected the spatial patterns of ω-gliadin synthesis and deposition, which were differentially increased in the outer layers of the starchy endosperm with high levels of nitrogen.

Conclusions
Wheat ω-gliadins vary in amount and composition between cultivars, and in their response to nitrogen supply. Their spatial distribution is also affected by nitrogen supply, being most highly concentrated in the sub-aleurone cells of the starchy endosperm under higher nitrogen availability.

Year of Publication2014
JournalAnnals of Botany
Journal citation113, pp. 607-615
Digital Object Identifier (DOI)doi:10.1093/aob/mct291
PubMed ID24344140
PubMed Central IDPMC3936585
Open accessPublished as ‘gold’ (paid) open access
Funder project or codeDesigning Seeds for Nutrition and Health (DS)
Designing cereal seeds for nutrition and health
[20:20 Wheat] Maximising yield potential of wheat
FunderBiotechnology and Biological Sciences Research Council
Publisher's version
Output statusPublished
Publication dates
Online15 Dec 2013
Publication process dates
Accepted13 Nov 2013
Copyright licenseCC BY
PublisherOxford University Press (OUP) Oxford
Oxford University Press (OUP)
ISSN0305-7364

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