Transcriptome and Metabolite Insights into Domestication Process of Cultivated Barley in China

The domestication process of cultivated barley in China remains under debate because of the controversial origins of barley. Here, we analyzed transcriptomic and non-targeted metabolic data from 29 accessions together with public resequencing data from 124 accessions to explore the domestication process of cultivated barley in China (Cb-C). These analyses revealed that both Cb-C and Tibetan wild barley (Wb-T) were the descendants of wild barley from the Near East Fertile Crescent (Wb-NE), yielding little support for a local origin of Wb-T. Wb-T was more likely an intermediate in the domestication process from Wb-NE to Cb-C. Wb-T contributed more genetically to Cb-C than Wb-NE, and was domesticated into Cb-C about 3300 years ago. These results together seem to support that Wb-T may be a feralized or hybrid form of cultivated barley from the Near East Fertile Crescent or central Asia. Additionally, the metabolite analysis revealed divergent metabolites of alkaloids and phenylpropanoids and these metabolites were specifically targeted for selection in the evolutionary stages from Wb-NE to Wb-T and from Wb-T to Cb-C. The key missense SNPs in the genes HORVU6Hr1G027650 and HORVU4Hr1G072150 might be responsible for the divergence of metabolites of alkaloids and phenylpropanoids during domestication. Our findings allow for a better understanding of the domestication process of cultivated barley in China.

Agro-morphological traits-based genetic diversity assessment in Ethiopian barley (Hordeum vulgare L.) landrace collections from Bale highlands, Southeast Ethiopia

Background Cultivated barley (Hordeum vulgare L.) is one of the world’s important cereal crops. Ethiopia is claimed to be the centre of origin due to its high phenotypic diversity and flavonoid patterns. It is widely cultivated on subsistence bases and important in supporting the livelihood of local poor. However, the local landraces are currently under threat of severing genetic erosion. Hence, assessing the extents of its genetic diversity is timely in improvement and conservation. Methodology 120 representative cultivated barley landraces have been collected from Bale highlands, Ethiopia, and tested at two locations using alpha lattice design. Data were collected on 21 agro-morphometric traits and analysed using MINITAB 19, SAS 9.4 and FigTree v1.4.3. Results Most morphotypes in each of the qualitative traits considered and mean performance values in most of the quantitative traits revealed wide range of variations suggesting existence of phenotypic diversity among the landraces. Analysis of variance also showed significant variations among the landraces. All the traits, except days to maturity and plant height showed a significant variation for location and treatment-location interactions revealing the high impact of environmental conditions on the variations. Estimates of the variance components also revealed a wider range of variations in most of the traits considered with eventual medium to low genotypic (GCV), phenotypic (PCV) and genotype–environment coefficients of variation (GECV). Estimates of heritability in broad sense (H2) is low (< 40%) in all the traits except in days to maturity. Grouping of the landraces showed poor geographic areas of collection-based pattern suggesting extensive gene flow among the areas. Conclusion The landraces evaluated in the present study showed high morphological diversity. However, the effect of environment factor is pronounced and thus, multiple locations and years with large number of samples must be considered to exploit the available genetic-based variations for breeding and conservation of the crop.

Evaluation of a Set of Hordeum vulgare subsp. spontaneum Accessions for β-Glucans and Microelement Contents

Barley is one of the oldest domesticated crops in the world and is mainly used for feed and malt and to a lesser extent as food. The use of barley as food is a tradition in communities in some countries of North Africa, Europe, and Asia. However, due to the health-promoting properties of barley grain, there is an increasing interest in such use. The International Center for Agricultural Research in the Dry Areas (ICARDA) has a global mandate for barley improvement and holds rich in-trust collections of cultivated and wild Hordeum species. The present study aims to evaluate 117 accessions of Hordeum spontaneum for their contents of β-glucan and microelements for breeding new varieties with enhanced nutritional value. The bulked seed accessions of Hordeum spontaneum were grown over two seasons, and the single plant derived seeds from these accessions were compared to 36 elite lines and varieties of cultivated barley in the second season in Morocco. The results showed large differences in β-glucan and microelements in both the bulk and the single plant seed accessions. The contents of β-glucans ranged from 1.44 to 11.3% in the Hordeum spontaneum accessions and from 1.62 to 7.81% in the cultivated barley lines. Large variations were found for the microelements content, but no differences were noticed between the wild and the cultivated species. However, some accessions of Hordeum spontaneum had higher combined contents of Iron, Zinc, and Selenium. Such accessions are used in interspecific crosses to develop biofortified barley germplasm and varieties.

Phenotypic Evolution of The Wild Progenitor of Cultivated Barley (Hordeum Vulgare Subsp. Spontaneum (C. Koch) Thell.) Across Bioclimatic Regions In Jordan

Climate change affects the evolutionary potential and the survival of wild plant populations by acting on fitness traits. Resurrection approach was applied to investigate the phenotypic changes during the evolution of the wild progenitor of cultivated barley, Hordeum spontaneum K. Koch in Jordan. We compared 40 Hordeum spontaneum K. Koch populations collected in Jordan in 1991 with 40 Hordeum spontaneum K. Koch populations collected from the same sites in 2014. In the comparison we included seven Hordeum vulgare checks (one local landrace and six improved varieties). The analysis of the phenotypic data showed that the populations were aggregated according to their ecological geographical pattern in two groups with a significant (p < 0.0001) correlation between groups. Four heritable traits, namely plant height, biological yield, number of tillers, and awn length, determined the phenotypic structure of the populations. The two populations collected at 23 years distance, diverged in two distinctive phenotypic structure categories; a conserved structure and an evolved structure with a reduction in the phenotypic trait diversity in the population collected in 2014. These results reveal the value of combining phenotypic and environmental data to understand the evolution and adaptation of the population to climate change over a long period and the consequences on the wild progenitor of cultivated barley collection to avoid loss of genetic materials.

Single Nucleotide Polymorphisms in Bmy1 Intron III Alleles Conferring the Genotypic Variation in β-amylase Activity under Drought Stress Between Tibetan Wild and Cultivated Barley

β-amylase activity is related to the polymorphism of Bmy1 intron III; however, no attention has been given to such relationship under environmental stresses like drought. In this study, 73 cultivated barley genotypes and 52 Tibetan wild barley accessions were used to test the association between Bmy1 gene intron III polymorphisms and β-amylase activity under drought stress. Our results showed that three alleles, Bmy1.a, Bmy1.b and Bmy1.c, existed in the examined barley genotypes. Tibetan wild barley had higher proportion of Bmy1.b, whereas cultivated barley showed higher proportion of Bmy1.a. Impressively, barley genotypes with Bmy1.b showed significant increase in β-amylase activity under drought stress, compared with those with Bmy1.a or Bmy1.c, indicating that Bmy1.b allele might provide more chances for developing barley cultivars with higher β-amylase activity under water stress than both Bmy1.a and Bmy1.c alleles. Furthermore, the Tibetan wild barley XZ147, belonging to Bmy1.b allele type, showed significant higher β-amylase activity than the cultivar Triumph under drought stress. This might result from the unique amino acid substitution M527 or the amino acid composition of R115, D165, A233, S347 and M527 of XZ147.

Transcriptome and Metabolite Insights Into Domestication Process of Cultivated Barley in China

Background Barley is one of the earliest domesticated crops and regarded as one of the founder of Neolithic transition in the Near East Fertile Crescent. Domestication process of cultivated barley (especially east-Asian cultivated barley) has been under debate because of the controversial origin centers of barley, which caused by widely dispersal of wild barley. What’s more, no comprehensive study regarding alteration in metabolism during domestication has been delineated in barley so far. Results Transcriptomic and non-targeted metabolic analyses were performed for two wild barley populations (wild barley of Near East Fertile Crescent (Wb-NE), and wild barley of Tibetan Plateau (Wb-T)), and one cultivated barley population (cultivated barley of China (Cb-C)), the results revealed two stages of the domestication process of Cb-C, first from Wb-NE to Wb-T, and then from Wb-T to Cb-C. The Wb-T played an important intermediate role in the domestication from Wb-NE to Cb-C, and had made more genetic contribution than Wb-NE to Cb-C. Meanwhile, we found continuous gene flow, a large number of selective genes and metabolites during domestication. Divergent metabolites of alkaloids and phenylpropanoids were specific targeted in stages from Wb-NE to Wb-T and from Wb-T to Cb-C, respectively. The key missense SNPs in genes HORVU6Hr1G027650 and HORVU4Hr1G072150 might be related to the divergence of metabolites of alkaloids and phenylpropanoids during domestication. Conclusions Our results revealed that two stages of the domestication process of Cb-C, and distinct sets of metabolites were targeted by selection during the evolution from wild barley of the Near East Fertile Crescent to Tibetan wild barley to cultivated barley of China. Our findings not only provided genetic and metabolic insights into domestication process of barley but also highlighted the power of combining omics data for trait dissection.