Varietal identification of single seeds of barley by analysis of hordein polypeptides

Abstract

Methods for the extraction and separation of hordein fractions from single or halfseeds of barley have been evaluated. Sodium dodecylsulphate-polyacrylamide gel electrophoresis at pH 8.9 gave rapid and reproducible separations of reduced and alkylated hordein, and this system was used to analyse hordein fractions from 88 barley varieties. On the basis of this character the varieties can be divided into 29 groups, each containing between one and 25 varieties. The largest group can be further divided into four subgroups on the basis of minor hordein polypeptide differences revealed by a second electrophoretic system, urea polyacrylamide gel electrophoresis at pH 4.6. Of the samples of the varieties studied, all except five contained seed homogeneous with respect to hordein polypeptide pattern. It is concluded that analysis of hordein polypeptide patterns from single seeds is of great potential value, both for the commercial identification of grain samples and as an aid to existing techniques for the establishment of varietal distinctness.

Hordein and Malting Quality in Northern Barleys

“…Two different extraction methods were used: Method 1. -Hordein was extracted by using a modified method of SHEWRY et al (1978a). Sample buffer contained 55 YO (v/v) 2-propanol and…”

“…The A hordeins (molecular weight < 20 kDa) are not considered true storage proteins (SHEWRY et al 1978a). In turn, B and C hordeins (molecular weight from 35 to 46 kDd and from 55 to 72 kDd, respectively) vary considerably in protein composition.…”

“…Many authors (e.g., SHEWRY et al 1978aSHEWRY et al , 1980aSMITH and SIMPSON 1983;ROININEN et al 1992) have used hordein banding patterns to identify barley varieties. Little is known, however, of the extent of genetic variation in hordein quality, although it could significantly affect malting quality.…”

Hordein Polypeptide Pattern in Relation to Malting Quality and the Varietal Identification of Malted Barley Grain

“…22 The only recorded effect of growth conditions is an increase in the relative amount of *C hordein with increasing seed N.9 However we find that this effect is relatively small, an increase from 1-26% to 203 % N resulting in an increase in 'C hordein from 130% to 18-5% of the total hordein fraction of Julia.1' Although we have not specifically studied grains differing in texture (mealy and steely or vitreous), we have found little variability between single seeds in the ratio of B: C hordein. It should be noted, however, that whereas Baxter and Wainwright1 extracted hordein with hot 70% ethanol without a reducing agent, we used 50% propan-1-ol + 2% 2-mercaptocthanol, which we have found to give more complete extraction of 'fl' hordein.…”

The genetic analysis of barley storage proteins

“…Hordein fractions were extracted from half seed of cross 1 as described previously (Shewry et al, 1978b). They were dissolved in 50 1 of 8 M urea and 1 per cent (vfv) 2-mercaptoethanol, alkylated with 4-vinylpyridine (1.5 per cent v/v) and 25 1 aliquots used for 2-D analysis.…”