Defining genetic and chemical diversity in wheat grain by 1H-NMR spectroscopy of polar metabolites.

Peter R Shewry,Delia I Corol,Jane L Ward,Huw D Jones,Michael H Beale

doi:10.1002/mnfr.201600807

Abstract

ScopeThe application of high‐throughput 1H nuclear magnetic resonance (1H‐NMR) of unpurified extracts to determine genetic diversity and the contents of polar components in grain of wheat.Methods and resultsMilled whole wheat grain was extracted with 80:20 D2O:CD3OD containing 0.05% d4–trimethylsilylpropionate. 1H‐NMR spectra were acquired under automation at 300°K using an Avance Spectrometer operating at 600.0528 MHz. Regions for individual metabolites were identified by comparison to a library of known standards run under identical conditions. The individual 1H‐NMR peaks or levels of known metabolites were then compared by Principal Component Analysis using SIMCA‐P software.ConclusionsHigh‐throughput 1H‐NMR is an excellent tool to compare the extent of genetic diversity within and between wheat species, and to quantify specific components (including glycine betaine, choline, and asparagine) in individual genotypes. It can also be used to monitor changes in composition related to environmental factors and to support comparisons of the substantial equivalence of transgenic lines.

Highlights

Wheat is the third most important cereal crop in the world in terms of total production; the annual production over the five year period from 2008 to 2012 averaging about 680 million tonnes
Most of the wheat grown globally is bread wheat (T. aestivum), but other species are grown to a lesser extent, notably about 35-40 million tonnes a year of durum wheat (T. turgidum var. durum), a tetraploid species related to emmer, which is grown in the hot dry climate of the Mediterranean and similar areas
We have developed high throughput hydrogen-1 nuclear magnetic resonance (1H-NMR) analysis of unpurified extracts made directly into deuterated aqueous methanol as a routine screening tool in plant metabolomics [8,9]

Summary

Introduction

Wheat is the third most important cereal crop in the world in terms of total production; the annual production over the five year period from 2008 to 2012 averaging about 680 million tonnes (http://faostat.fao.org/site/339/default.aspx) It is the most widely grown cereal, being the dominant crop in temperate zones and grown from Scandinavia to the south of Argentina, including highlands in the tropics [1]. Small volumes of “ancient” wheat species are grown for traditional foods or to satisfy the increasing demand for “healthy” alternatives to modern bread and pasta wheats. These are einkorn, emmer, (which are discussed above) and spelt which is a hexaploid form related to bread wheat These ancient wheat species are “hulled”, in that the glumes adhere tightly to the grain and need to be removed before processing, whereas modern bread and durum wheats are free threshing

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Conclusion