Resistance to a non-adapted pathogen of barley is linked to the evolution of the Poales-specific Exo70FX family

Holden, Samuel (2021) Resistance to a non-adapted pathogen of barley is linked to the evolution of the Poales-specific Exo70FX family. Doctoral thesis, University of East Anglia.

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Abstract

Three loci contribute to resistance in barley against the non-adapted pathogen Puccinia striiformis f. sp. tritici: Rps6, Rps7 and Rps8. Using a high-resolution recombination screen, a forward genetic screen, natural variation, and transgenic complementation we identify two adjacent genes on the long arm of chromosome 4H which are both necessary for Rps8-mediated resistance. These genes are in genetic coupling and are inherited together as part of a 546 kb In/Del polymorphism between Rps8 and rps8 haplotypes. These genes encode an Exo70 protein and an LRR-XII family receptor kinase protein; the Exo70 is a member of the Exo70FX clade which has only been identified in the Poaceae, and the receptor kinase is a member of the LRR-XII clade which is widely conserved across plants and includes the well-studied resistance genes FLS2, EFR and Xa21. We perform an analysis of the Exo70FX clade in the Poales and identify the origins of Exo70FX in the graminid clade. We also catalogue extensive species-specific expansion of Exo70FX subclades throughout the Poaceae as well as sequence-level diversity within and between subclades. We identify the Exo70 at Rps8 as a member of a novel subclade: Exo70FX12, which is a recent innovation of the Pooideae. To facilitate this analysis, we sequenced and annotated the first genome of Ecdeiocolea monostachya, a wild Australian plant which is a close outgroup of the Poaceae, assembling a diploid genome of 1.33 Gbp, covering an estimated 87% of the genome with 84,700 gene annotations.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Science > School of Biological Sciences
Depositing User: Chris White
Date Deposited: 13 Oct 2021 15:30
Last Modified: 13 Oct 2021 15:30
URI: https://ueaeprints.uea.ac.uk/id/eprint/81695
DOI:

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