Harnessing wheat resistance to stem rust through wheat-rye introgression strategies

Abstract

Wheat (Triticum aestivum L.) is one of the most important cereals worldwide that provides necessary daily protein and nutrition for humans. Unfortunately, this crop yield capacity is affected by various challenges. One of the key challenges is the emergence of new races of stem and stripe rust, which can overcome previously effective resistance genes. This emphasizes the critical need for new sources of resistance in wheat. This thesis explores the potential of wheat-rye introgression lines for improving wheat's resistance to these devastating pathogens. Using genotyping-by-sequencing (GBS) data and Kompetitive Allele-Specific PCR (KASP) markers, we developed a robust methodology to accurately track Sr59, a stem rust resistance gene, during breeding cycles and develop new wheat varieties with acceptable agronomic performance and resistance to stem rust. Additionally, we developed a new wheatrye translocation line (#284) having Sr59 as a small translocation, 2BS.2BL-2RL, located at the distal part of chromosome 2RL. This chromosomal segment is particularly advantageous for breeding programs due to its small size and simplicity of introgression into adapted wheat varieties. Further, GBS alignment with annotated rye nucleotide-binding leucine-rich repeat (NLR) genes identified two candidate NLRs on chromosome 2RL, further enriching our understanding of the genetic basis of resistance. Through phenotypic screening and molecular validation, we characterized a second stem rust resistance gene, SrSLU, present in line #C295, which exhibits broad-spectrum resistance to multiple stem rust races. To enhance durability and broaden resistance, we successfully pyramided Sr59 with YrSLU, a stripe rust resistance gene, into a single wheat line. In this approach, we used marker-assisted selection (MAS) and speed breeding technologies to accelerate breeding cycles while maintaining high agronomic performance through top-crossing with elite commercial varieties. The resulting lines combine robust resistance against both stem and stripe rust with improved yield potential. This research provides crucial insights into the use of wheat-rye as a source of novel resistance genes and advances methodologies for their precise characterization and development. These findings are important steps towards food security and the fight against hunger.

Keywords

Breeding; Durable disease resistance; Marker assisted selection; Resistance gene; Rye; Seedling resistance test; Stem rust; Stripe rust; wheat; Wheat-rye introgression

Published in

Acta Universitatis Agriculturae Sueciae
2025, number: 2025:21
Publisher: Swedish University of Agricultural Sciences

SLU Authors

• Yazdani, Mahboobeh

  • Department of Plant Breeding, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Genetics and Breeding in Agricultural Sciences
Botany

Publication identifier

• DOI: https://doi.org/10.54612/a.7sg5ufn9ft
• ISBN: 978-91-8046-456-7
• eISBN: 978-91-8046-506-9

Permanent link to this page (URI)

https://res.slu.se/id/publ/132961