Adult plant stem rust resistance in durum wheat Glossy Huguenot: mapping, marker development and validation.

Rohit Mago,Kerrie Forrest,Evans Lagudah,Geetha Perera,Alex Whan,Mandeep Randhawa,Urmil Bansal,Ravi P Singh,Chunhong Chen,Sutha Chandramohan,Xiaodi Xia,Matthew Hayden,Julio Huerta-Espino,Bhoja R Basnet,Harbans Bariana

doi:10.1007/s00122-022-04052-9

Abstract

Adult plant stem rust resistance locus, QSrGH.cs-2AL, was identified in durum wheat Glossy Huguenot and mendelised as Sr63. Markers closely linked with Sr63 were developed. An F3 population from a Glossy Huguenot (GH)/Bansi cross used in a previous Australian study was advanced to F6 for molecular mapping of adult plant stem rust resistance. Maturity differences among F6 lines confounded assessments of stem rust response. GH was crossed with a stem rust susceptible F6 recombinant inbred line (RIL), GHB14 (M14), with similar maturity and an F6:7 population was developed through single seed descent method. F7 and F8 RILs were tested along with the parents at different locations. The F6 individual plants and both parents were genotyped using the 90K single nucleotide polymorphism (SNP) wheat array. Stem rust resistance QTL on the long arms of chromosomes 1B (QSrGH.cs-1BL) and 2A (QSrGH.cs-2AL) were detected. QSrGH.cs-1BL and QSrGH.cs-2AL were both contributed by GH and explained 22% and 18% adult plant stem rust response variation, respectively, among GH/M14 RIL population. RILs carrying combinations of these QTL reduced more than 14% stem rust severity compared to those that possessed QSrGH.cs-1BL and QSrGH.cs-2AL individually. QSrGH.cs1BL was demonstrated to be the same as Sr58/Lr46/Yr29/Pm39 through marker genotyping. Lines lacking QSrGH.cs-1BL were used to Mendelise QSrGH.cs-2AL. Based on genomic locations of previously catalogued stem rust resistance genes and the QSrGH.cs-2AL map, it appeared to represent a new APR locus and was permanently named Sr63. SNP markers associated with Sr63 were converted to kompetetive allele-specific PCR (KASP) assays and were validated on a set of durum cultivars.

Highlights

Stem rust, caused by Puccinia graminis f. sp. tritici (Pgt), is one of the most devastating fungal diseases affecting wheat production worldwide
With the objective to map the adult plant stem rust resistance in Glossy Huguenot we developed a recombinant inbred line (RIL) F6:7 population and conducted QTL analysis using the 90k single nucleotide polymorphism (SNP) wheat array and identified resistance-linked molecular markers
The map of the Glossy Huguenot (GH)/M14 RIL population (192 lines) comprised 23 linkage groups, each of which mapped with high confidence to one of the 14 durum chromosomes

Summary

Introduction

Stem rust, caused by Puccinia graminis f. sp. tritici (Pgt), is one of the most devastating fungal diseases affecting wheat production worldwide. Of the 62 stem rust resistance genes that have been described; most belong to the race-specific all-stage resistance (ASR) category. These genes generally confer high to moderate levels of resistance to avirulent races but are often short lived due to the emergence of new races with virulence for commercially deployed resistance genes. A few adult plant (APR) stem rust resistance genes include Sr2 (McFadden 1930), Sr55 (Herrera-Foessel et al 2014), Sr56 (Bansal et al 2014), Sr57 and Sr58 (Singh et al 2015). APR genes typically reduce the growth rate of the pathogen (Herrera-Foessel et al 2012) and may be race nonspecific. APR genes are known to interact with ASR genes to enhance their expression (Ayliffe et al 2013; Bariana et al 2001; Lagudah 2011)

Methods

Results

Conclusion