Epistatic determinism of durum wheat resistance to the wheat spindle streak mosaic virus

Yan Holtz,Véronique Marie-Jeanne,Gérard Poux,Nicolas O Rode,Michel Bonnefoy,Morgane Ardisson,Vincent Ranwez,Sylvain Santoni,David Gouache,Pierre Roumet,Véronique Viader,Jacques L David

doi:10.1007/s00122-017-2904-6

Abstract

Key messageThe resistance of durum wheat to the Wheat spindle streak mosaic virus (WSSMV) is controlled by two main QTLs on chromosomes 7A and 7B, with a huge epistatic effect.Wheat spindle streak mosaic virus (WSSMV) is a major disease of durum wheat in Europe and North America. Breeding WSSMV-resistant cultivars is currently the only way to control the virus since no treatment is available. This paper reports studies of the inheritance of WSSMV resistance using two related durum wheat populations obtained by crossing two elite cultivars with a WSSMV-resistant emmer cultivar. In 2012 and 2015, 354 recombinant inbred lines (RIL) were phenotyped using visual notations, ELISA and qPCR and genotyped using locus targeted capture and sequencing. This allowed us to build a consensus genetic map of 8568 markers and identify three chromosomal regions involved in WSSMV resistance. Two major regions (located on chromosomes 7A and 7B) jointly explain, on the basis of epistatic interactions, up to 43% of the phenotypic variation. Flanking sequences of our genetic markers are provided to facilitate future marker-assisted selection of WSSMV-resistant cultivars.

Highlights

Wheat spindle streak mosaic virus (WSSMV) infects bread and durum wheats in Europe and North America (Ordon et al 2009)
An average of 2.5 and 4 million reads per sample were obtained for Dic2 × Silur (DS) and Dic2 × Lloyd (DL), respectively, and 86 and 75% of these reads were mapped successfully on DWr, the durum wheat reference transcriptome
For DS, five markers were not linked to any other SNP and were not used in the genetic map

Summary

Introduction

Wheat spindle streak mosaic virus (WSSMV) infects bread and durum wheats in Europe and North America (Ordon et al 2009). Symptoms of WSSMV include yellow-striped mosaic patterns on leaves and stunted spring growth, resulting in extensive damage and yield loss (Miller et al 1992). WSSMV is transmitted by Polymyxa graminis (Adams 1990), a Plasmodiophoridae (Schwelm et al 2015) that is soil-borne. P. graminis is an obligate parasite of wheat and other Poaceae roots. WSSMV infection starts in the roots, and progresses to the aerial parts of the plant including the leaves (Carroll et al 1997). Mosaic symptoms are mostly visible in leaves and characterized by cytoplasmic inclusions in infected cells (Sohn et al 1995)

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Results

Conclusion