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

Yu Zhou,Xifeng Ren,Guang Lu,Daokun Sun,Genlou Sun

doi:10.3390/plants11020209

Abstract

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.

Highlights

Barley is one of the earliest domesticated crops and is regarded as one of the founders of the Neolithic transition in the Near East Fertile Crescent [1]
The genetic diversity analysis for the three groups of barley accessions revealed that Wb-NE had the highest nucleotide diversity (π = 0.23036), highest Watterson’s estimator, highest minor allele frequency (MAF = 0.1745), and greatest polymorphism information content (PIC = 0.2176) (Table 1)
One suggests that the cultivated barley in China was introduced from the Near East Fertile Crescent [14,34,35], and another proposes that cultivated barley in China might have locally derived from two-rowed or six-rowed wild barley from the Qinghai Tibet Plateau [36,37]

Summary

Introduction

Barley is one of the earliest domesticated crops and is regarded as one of the founders of the Neolithic transition in the Near East Fertile Crescent [1]. Unlike wheat and other founder crops, the widely eastward dispersal of wild barley Spontaneum and H. agriocrithon Åberg), an increasing number of studies proposed that Tibet was one of the centers of barley domestication [6,7,8,9,10]. The existence of Tibetan wild barley only provided weak evidence for the hypothesis that Tibet was one of the centers of barley origin or domestication. Tibetan cultivated barley (qingke) was derived from the Fertile Crescent, and was first introduced to southern Tibet most likely via north Pakistan, India, and Nepal between 3500 and 4500 years ago [11]

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