The origin of six-rowed ‘wild’ barley from the western Himalaya

Summary Plants were grown from seed of two-rowed wild barley, Hordeum spontaneum, and six-rowed brittlerachised barley. H. agriocrithon, collected in Ladakh, north-western India. Whereas the H. spontaneum remained true to type, segregation for morphological characters was observed in progeny rows grown from heads of H. agriocrithon plants. The H. agriocrithon heads also showed segregation for a biochemical character, the polypeptide pattern of the endosperm storage protein fraction (hordein). The H. agriocrithon seed therefore originated from natural hybridization between cultivated H. vulgare and weedy H. spontaneum. Crosses of H. vulgare and H. spontaneum gave progeny which resembled H. agriocrithon and showed similar hordein polypeptide segregation patterns. The results indicate that six-rowed brittle-rach ised barleys from the Himalayas have a similar origin to forms found in the Middle East, and that H. agriocrithon does not play a direct role in the evolution of barley.     

大麦醇溶蛋白及其酶解产物的抗氧化活性研究

为了探寻出大麦蛋白中最具抗氧化活性的片段,对大麦醇溶蛋白粗提物及其酶解产物的抗氧化活性进行研究。从大麦面粉中提取大麦醇溶蛋白,对其粗提物进行凝胶层析法分离纯化,并模拟人体消化道系统酶解得到不同组分的酶解产物,采用FTC法及FARP法对酶解前后及不同组分酶解产物的抗氧化活性进行比较。结果显示,大麦醇溶蛋白酶解产物的抗氧化活性显著高于其未经酶解的粗提物,酶解产物中C-大麦醇溶蛋白的活性显著高于其他组分。可见,大麦醇溶蛋白是一种优良的天然抗氧化剂,并且经消化酶解会大大提高其抗氧化活性。     

Endosperm protein accumulation in wild and cultivated barley and their cross grown in spike culture

Summary The high protein wild relatives of cultivated cereals have proven difficult to utilize in plant breeding by direct selection for high grain protein percentage, and hence alternative selection criteria are needed. In this study, a spike culture method was used to measure differences in protein accumulation between wild and cultivated barley, and their cross, at different levels of nitrogen supply. Three genotypes, barley cultivar Hordeum vulgare L. cv. Clipper, a wild barley accession H. spontaneum Koch line 363, and a high protein F₅ line (38.4) derived from their cross, were grown from 8 to 27 days after flowering in in vitro spike culture. Nitrogen supply in the culture medium was either 0.4 g/l or 2.0 g/l of N supplied as NH₄NO₃. Spikes were harvested at approximately 3 day intervals during grain development, and salt soluble and hordein protein fractions were measured. Lines 363 and 38.4 differed from Clipper in having extremely high initial rates of protein accumulation, even at 0.4 g/l N. In high nitrogen conditions all three genotypes reached similar salt soluble plus hordein protein levels. Hordein-1 and hordein-2 fractions were measured separately; the percent of hordein-1 was higher in lines 363 and 38.4 than in Clipper at 0.4 g/l N. For all parameters measured, pot-grown spikes of matching age were harvested and were shown to be similar to the 0.4 g/l N treatment. The possible utilization of spike culture for identification of critical protein accumulation parameters is discussed, in relation to their possible utilization in breeding.     

Relationships Between Barley Hordeins and Malting Quality in a Mutant of cv. Triumph I. Genotype by Environment Interaction of Hordein Content

The genetic (G), environmental (E) and G×E effects on total grain protein and hordein fractions, have been studied in a mutant (TL43) and its parent cultivar, the malting barley Triumph, in various seasons at Dundee (E Scotland) and Lleida (NE Spain). The grain protein content of TL43 was consistently about 2% higher than that of Triumph across environments. Differences in hordein composition were shown by SDS-PAGE electrophoresis. TL-43 had three B-hordein bands not present in Triumph which had a further three bands of the same hordein group not present in TL43. TL43 showed higher B-hordein content than Triumph in Scotland but lower in Spain, whereas the mutant showed consistently higher C- and D-hordein content than Triumph across environments, i.e. there was crossover G×E interaction for B-hordein and non-crossover for C- and D-hordein content. There were also differences in grain ultra-structure between the two lines, as TL43 showed a more dense protein matrix than Triumph, together with thinner pericarp, testa and aleurone layers. It was concluded that the mutation in TL43 had a significant effect on storage protein composition.     

Antioxidative properties of partially purified barley hordein, rice bran protein fractions and their hydrolysates

Antioxidative properties of proteins from barley and rice bran and their hydrolysates were examined. Three major hordein fractions of barley, B, C and D hordeins, were partially purified by gel filtration. Albumin, globulin, prolamin and glutelin fractions of rice bran were fractioned by the Osborne method. Hydrolysates of these protein fractions were prepared by digesting with pepsin followed by trypsin. Antioxidant properties in terms of antioxidative activity against linoleic acid peroxidation and reducing activity without the lipid adjuvant were investigated. The globulin fraction from rice bran protein revealed the strongest antioxidative activity throughout the incubation time of 7 days (p ≤ 0.05). The albumin fraction of rice bran protein showed the highest reducing activity (6964 μmol of Fe²⁺) followed by globulin, prolamin, glutelin and hordein fractions with activities of 2904, 2017, 1809 and 1333 μmol of Fe²⁺, respectively (p ≤ 0.05). Partially purified C hordein exhibited the highest reducing activity compared with B and D hordeins. Protein hydrolysates obtained after digestion with pepsin and trypsin exhibited much greater antioxidative, as well as reducing, activities than those from before digestion.     

Proposal for the identification of barley varieties based on the genotypes for 2 hordein and 39 isoenzyme loci of 47 reference varieties

Summary Fifty-nine spring and 7 winter barley varieties in The Danish List of Varieties of Agricultural Crops, 1983/84 were examined for variation at 39 isoenzyme and two hordein loci. Twenty-three isoenzyme loci had one allele only, and 16 loci had from two to five alleles. One hordein locus had 12 and the other 15 alleles. The variation in the 16 enzyme loci permitted the division of the 66 varieties into 63 groups, while the two hordein loci produced 34 groups. A study of 20 individuals from each variety showed that 22 varieties were polymorphic in at least one locus. Eight starch gel electrophoresis with various buffer systems, one agar gel electrophoresis (for amylases), and one polyacrylamide gel electrophoresis (for hordein) were performed to develop the patterns associated with the 41 loci. The polyacrylamide gel electrophoresis developing hordein patterns was clearly the most powerful single system for identifying barley varieties because of the large number of alleles.     

新疆大麦种质资源农艺性状和醇溶蛋白遗传多样性分析

为给新疆大麦种质资源的开发利用和今后新疆大麦高产优质新品种的选育提供依据,根据大麦的8个农艺性状表现,采用酸性聚丙烯酰胺凝胶电泳(A-PAGE) 对国内外50份大麦种质资源的农艺性状和醇溶蛋白的遗传多样性进行了分析评价.结果表明,供试大麦品种农艺性状的变异系数(CV;)取值范围在9.15;～41.68;,平均23.96;.多样性指数(H)介于1.400～2.039,平均1.810.各农艺性状的遗传多样性指数都较大,具有丰富的遗传多样性;对供试材料的农艺性状进行聚类分析,50份大麦材料在遗传距离(GD)3.28时可被聚为5大类.利用A-PAGE对50个供试大麦品种进行检测,共分离出21种相对迁移率不同的醇溶蛋白谱带,即参试品种具有21个醇溶蛋白等位变异位点.平均每个品种分离出0.42条多态性谱带,表明这些品种具有丰富的遗传变异;对供试材料的醇溶蛋白电泳结果进行聚类分析,50份大麦材料在遗传距离(GD)0.44处聚为6个大类.     

The production and characterisation of Hor 3 null lines of barley provides new information on the relationship of D hordein to malting performance

Six pairs of near isogenic lines, differing in the presence of absence of D hordein, were produced in backgrounds with different B and C hordein alleles by introducing a Hor 3 null gene discovered in a barley germplasm collection. Biochemical and cytochemical studies were performed on the harvested and malted grains. Statistical comparisons of the composition of the grains and their malting performance revealed that neither presence or absence of D hordein, nor gel protein levels related to differences in malting performance of the different lines. However, differences in hordein amount and in the grain ultrastructural characteristics could be related to some differences in malting performance between and within some pairs of lines.     

Genes for the storage proteins of barley

The endosperm storage proteins of barley (hordeins) can be divided into four groups A, B, C and D. The A hordeins are probably not true storage proteins and their genetics has not been studied. The other three groups are specified by the lociHor-2, Hor-1 andHor-3, respectively. These all appear to map on chromosome 5 withHor-1 andHor-2 being linked both to each other (ca. 12% recombination) and to the mildew-resistance lociMla andMlk. The nature of the loci has been studied further by examining the chemical relationship between the proteins and by isolation of the mRNAs specifying them and the preparation of cDNA clones. N-terminal and C-terminal amino acid sequences of C hordein fractions show a high degree of structural homology. The relative positions of methionine residues in the polypeptide chains have been used to compare the various B hordein polypeptides. Cloning of double-stranded cDNA derived from endosperm poly A⁺ RNA has given rise to a family of B hordein-related DNAs, some of which have been sequenced. The results of these approaches suggest that the hordein loci are complex multigene families derived from single ancestral genes by cycles of gene duplication and mutation.     

Effects of enzymatic hydrolysis on molecular structure and antioxidant activity of barley hordein

Hordein, the major storage protein of barley (Hordeum vulgare L.), was hydrolysed by three selected proteases, including alcalase, flavourzyme and pepsin. The effects of protease type and hydrolysis time on hordein molecular weight, surface hydrophobicity, secondary structure and antioxidant activity were investigated. Flavourzyme hydrolysis of hordein was relatively more extensive and rapid, resulting in the formation of medium- and small-sized peptides with a broad distribution within 30 min. Alcalase and pepsin more gradually and less extensively hydrolysed hordein into medium- and larger-sized peptides, respectively. Protein surface hydrophobicity decreased with an increasing degree of hydrolysis. The flavourzyme and alcalase hydrolysates had superior DPPH (1,1-diphenyl-2-picryl hydrazyl) free radical scavenging activity (44-70 and 48-58%, respectively, at 0.5 mg/mL), Fe²⁺-chelating ability (21-64% and 39-73%, respectively, at 1 mg/mL), and superoxide radical scavenging capacity. It is proposed that the large- and medium-size hydrolysate fractions were most likely responsible for the antioxidant activities of hordein hydrolysates, and could be used as antioxidant peptides in food and nutraceutical applications.