Discovery and Chromosomal Location a Highly Effective Oat Crown Rust Resistance Gene Pc50-5.

Joanna Toporowska,Sylwia Sowa,Aneta Koroluk,Edyta Paczos-Grzęda,Andrzej Kilian

doi:10.3390/ijms222011183

Abstract

Crown rust, caused by Puccinia coronata f. sp. avenae, is one of the most destructive fungal diseases of oat worldwide. Growing disease-resistant oat cultivars is the preferred method of preventing the spread of rust and potential epidemics. The object of the study was Pc50-5, a race-specific seedling crown rust resistant gene, highly effective at all growth stages, selected from the differential line Pc50 (Avena sterilis L. CW 486-1 × Pendek). A comparison of crown rust reaction as well as an allelism test showed the distinctiveness of Pc50-5, whereas the proportions of phenotypes in segregating populations derived from a cross with two crown rust-susceptible Polish oat cultivars, Kasztan × Pc50-5 and Bingo × Pc50-5, confirmed monogenic inheritance of the gene, indicating its usefulness in oat breeding programs. Effective gene introgression depends on reliable gene identification in the early stages of plant development; thus, the aim of the study was to develop molecular markers that are tightly linked to Pc50-5. Segregating populations of Kasztan × Pc50-5 were genotyped using DArTseq technology based on next-generation Illumina short-read sequencing. Markers associated with Pc50-5 were located on chromosome 6A of the current version of the oat reference genome (Avena sativa OT3098 v2, PepsiCo) in the region between 434,234,214 and 440,149,046 bp and subsequently converted to PCR-based SCAR (sequence-characterized amplified region) markers. Furthermore, 5426978_SCAR and 24031809_SCAR co-segregated with the Pc50-5 resistance allele and were mapped to the partial linkage group at 0.6 and 4.0 cM, respectively. The co-dominant 58163643_SCAR marker was the best diagnostic and it was located closest to Pc50-5 at 0.1 cM. The newly discovered, very strong monogenic crown rust resistance may be useful for oat improvement. DArTseq sequences converted into specific PCR markers will be a valuable tool for marker-assisted selection in breeding programs.

Highlights

Oat (Avena sativa L.) is an important cereal crop used in the food industry and for animal feed and fodder [1]
The responses of Pc50, Pc50Au, Pc50-2, Pc50-4 and Pc50-5 to 14 P. coronata race inoculation were compared in the host-pathogen test to prove the distinctiveness of the newly discovered isoline Pc50-5 from the rest of the lines derived from the progeny of the seemingly homogeneous Pendek × A. sterilis CW 486-l hybrid
Pc50 was included in the reference oat line set in our previous study focused on monitoring the occurrence and harmfulness of P. coronata populations in Poland in the years 2013–2019 [19,20]

Summary

Introduction

Oat (Avena sativa L.) is an important cereal crop used in the food industry and for animal feed and fodder [1]. It ranks seventh in grain production, reaching approximately 23 million tons, with Russia, Canada, Australia and Poland being the largest oat producing countries [2]. Oat leaf diseases are responsible for significant decreases in yield quantity and quality in all areas of oat cultivation [3]. Crown rust, caused by Puccinia coronata f. Avenae, is one of the most devastating fungal diseases of oat in the world [4]. Growing disease-resistant oat cultivars is the most effective strategy for controlling crown rust.

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Methods

Results

Conclusion