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Proc Natl Acad Sci U S A. 2018 May 15;115(20):5223-5228. doi: 10.1073/pnas.1721749115. Epub 2018 Apr 30.

Genomic adaptation to drought in wild barley is driven by edaphic natural selection at the Tabigha Evolution Slope.

Author information

1
Department of Agronomy, Zhejiang Key Lab of Crop Germplasm, Zhejiang University, 310058 Hangzhou, China.
2
School of Science and Health, Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW 2753, Australia.
3
Institute of Evolution, University of Haifa, Mount Carmel, 34988384 Haifa, Israel nevo@research.haifa.ac.il fdai@zju.edu.cn.
4
Department of Agronomy, Zhejiang Key Lab of Crop Germplasm, Zhejiang University, 310058 Hangzhou, China; nevo@research.haifa.ac.il fdai@zju.edu.cn.

Abstract

Ecological divergence at a microsite suggests adaptive evolution, and this study examined two abutting wild barley populations, each 100 m across, differentially adapted to drought tolerance on two contrasting soil types, Terra Rossa and basalt at the Tabigha Evolution Slope, Israel. We resequenced the genomes of seven and six wild barley genotypes inhabiting the Terra Rossa and basalt soils, respectively, and identified a total of 69,192,653 single-nucleotide variants (SNVs) and insertions/deletions in comparison with a reference barley genome. Comparative genomic analysis between these abutting wild barley populations involved 19,615,087 high-quality SNVs. The results revealed dramatically different selection sweep regions relevant to drought tolerance driven by edaphic natural selection within 2,577 selected genes in these regions, including key drought-responsive genes associated with ABA synthesis and degradation (such as Cytochrome P450 protein) and ABA receptor complex (such as PYL2, SNF1-related kinase). The genetic diversity of the wild barley population inhabiting Terra Rossa soil is much higher than that from the basalt soil. Additionally, we identified different sets of genes for drought adaptation in the wild barley populations from Terra Rossa soil and from wild barley populations from Evolution Canyon I at Mount Carmel. These genes are associated with abscisic acid signaling, signaling and metabolism of reactive oxygen species, detoxification and antioxidative systems, rapid osmotic adjustment, and deep root morphology. The unique mechanisms for drought adaptation of the wild barley from the Tabigha Evolution Slope may be useful for crop improvement, particularly for breeding of barley cultivars with high drought tolerance.

KEYWORDS:

Hordeum spontaneum; drought adaptation; evolution models; genome resequencing; microsites

PMID:
29712833
PMCID:
PMC5960308
DOI:
10.1073/pnas.1721749115
[Indexed for MEDLINE]
Free PMC Article

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