Allocation of the oat powdery mildew resistance gene Pm3 to oat chromosome 1A

Volker Mohler

doi:10.1007/s42976-021-00152-2

Abstract

Besides the mode of inheritance, the knowledge of the chromosome location and allelic relationships are the essentials towards a successful deployment and stacking of divergent disease resistance genes for a given pathogen in breeding programs. Powdery mildew of oats, to which 11 major resistance genes in the host Avena sativa L. have been characterized so far, is a prevalent fungal disease of the crop in Northwestern Europe. In the present study, the resistance gene Pm3 was mapped by linkage analysis relative to molecular markers from oat consensus linkage group Mrg18 which was recently determined to represent oat chromosome 1A. Pm3 was located at 67.7–72.6 cM on Mrg18 of the oat consensus map, a position at which also stem and crown rust resistance genes Pg13 and Pc91 and a large cluster of resistance gene analogs have been previously mapped. The closely linked marker GMI_ES03_c2277_336 was found to be useful for the prediction of Pm3 in gene postulation studies. Although the major effect of the widespread gene got lost over time, the known genome location with associated markers will assist revealing in future genetic studies whether there is a possible residual effect of the gene contributing to adult plant resistance.

Highlights

Cultivated oat (Avena sativa L.) to which approved health claims have been granted (Storsley et al 2014) is, though of its high value for human nutrition, low in acreage compared to other cereals like rice, wheat, and maize
Of the 32 framework markers mainly chosen from the 56.0–76.7 cM region of linkage group Mrg18 of the oat consensus map, showed polymorphism between the parental lines of the mapping population, were monomorphic and 5 were failures (Table S3)
Eight markers were located within a 3.2 cM-interval around Pm3: 4 single nucleotide polymorphism (SNP), 3 amplified fragment length polymorphism (AFLP), and restriction fragment length polymorphism (RFLP) cMWG706

Summary

Introduction

Cultivated oat (Avena sativa L.) to which approved health claims have been granted (Storsley et al 2014) is, though of its high value for human nutrition, low in acreage compared to other cereals like rice, wheat, and maize. Powdery mildew of oats, caused by the biotrophic fungus Blumeria graminis, is a major disease in the humid. Eleven major genes for resistance to powdery mildew in cultivated oats have been catalogued so far (Pm1-Pm11; Hsam et al 2014; Herrmann and Mohler 2018; Ociepa et al 2020), but many more sources, as yet uncharacterized, for resistance to powdery mildew do exist in oat landraces and wild relatives of different ploidy levels (Herrmann and Roderick 1996; Okoń et al 2014, 2016, 2018; Okoń and Kowalczyk 2020). The access to genes from lower ploidy levels for enhancing cultivated oat germplasm is challenging (e.g., Aung et al 1977, 2010; Thomas et al 1980), agriculture will benefit from this work

Methods

Results

Conclusion