Population genome sequencing of Aegilops tauschii gives insight to bread wheat evolution, and forms a powerful resource for association genetics

Liangliang Gao1, Kumar Gaurav2, Sanu Arora2, Paula Silva1,3, Javier Sánchez-Martín4, Richard Horsnell5, Emily Delorean1, Alison R. Bentley4, Beat Keller3, Jesse Poland1,6, Brande B. H. Wulff2,6, Open Wild Wheat Consortium.

1** Department of Plant Pathology and Wheat Genetics Resource Center IUCRC, Kansas State University.

2** John Innes Center, Norwich Research Park, Norwich, UK .

3** Programa acional de Cultivos de Secano, nstituto acional de nvestigaci n Agropecuaria A , Estaci n Experimental a Estanzuela, Colonia, Uruguay.

4** Department of Plant and Micrbial Biology, University of Zurich, Switzerland.

5** The John Bingham Laboratory NIAB, Cambridge, UK.

6** King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.

lianggao@ksu.edu

Abstract

Bread wheat genomics continues to gain momentum. Following the completion of the first chromosome level genome assembly of Chinese Spring, multiple high quality bread wheat assemblies were published. Various groups conducted exome or whole genome shotgun sequencing of collections of bread wheat and its progenitors. There is much to still be learned about the wheat genome and in particular the diploid wild ancestors of wheat. We (the open wild wheat consortium team, OWWC, http://www.openwildwheat.org/team/) recently conducted whole genome sequencing (7-30x) of a global collection of 306 (242 non-redundant) accessions of Aegilops tauschii, the diploid D genome donor of bread wheat. Using this vast genomic resource, we sought to better understand wheat D-subgenome evolution, diversity and trait genetics. Our evidence suggests that a rare and geographically-restricted lineage (L3) contributed to the bread wheat D-subgenome. One example of such contribution can be found in the wheat flour quality gene Glu-D1. Through applying association genetics in this panel, we were able to rapidly map and identify candidates for multiple agronomically important genes including wheat curl mite resistant (Cmc4) and powdery mildew resistant (WTK4). These combined resources are available to the larger community and provide a powerful fast-track to gene discovery and cloning, enabling a new era in wheat genomics and accessing novel variation from wheat wild relatives.

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Keywords: :  Population sequencing, Aegilops tauschii, genome wide association study (GWAS), Lineage 3, Glu-D1.