Breaking the association between gametocidal gene(s) and leaf rust resistance gene (LrS2427) in Triticum aestivum-Aegilops speltoides derivative by gamma irradiation

• Published in: Molecular breeding 2024-08, Vol.44 (8), p.54, Article 54
• Main Authors: Ragini, R., Murukan, Niranjana, Sekhon, Navpreet Kaur, Chugh, Chetna, Agarwal, Priyanka, Yadav, Prachi, Mallick, Niharika, Jha, Shailendra Kumar, Iquebal, Mir Asif, Tandon, Gitanjali, Verma, Aakriti, Singh, Bhupinder, Jacob, Sherry Rachel, Raghunandan, K., Prabhu, Kumble Vinod, Tomar, Shivmangal Singh, Vinod
• Format: Article
• Language: English
• Subjects: Aegilops speltoides; Biomedical and Life Sciences; Biotechnology; Chromosome translocations; Chromosomes; Crop yield; Disease resistance; Disease transmission; Gamma irradiation; Gamma rays; Genes; Genetic diversity; Genomes; Genomic analysis; Goat grass; Interspecific hybridization; Irradiation; Leaf rust; Life Sciences; Pathogens; Plant breeding; Plant Genetics and Genomics; Plant Pathology; Plant Physiology; Plant Sciences; Quantitative trait loci; Resistant mutant; Seedlings; Seeds; Triticum aestivum; Wheat; Wild type; γ Radiation
• ISSN: 1380-3743; 1572-9788; 1572-9788
• DOI: 10.1007/s11032-024-01491-8

Utilization of crop wild relatives of wheat can be very effective in building the genetic diversity to cater to the evolving strains of disease pathogens. Aegilops speltoides is a rich source of rust resistance genes however transferring those to wheat genome can be tedious due to co-transfer and preferential transmission of undesirable genes causing gametocidal activity. Such an unholy association was observed in Triticum aestivum - Ae. speltoides derivative line Sel. 2427 which possess the broad-spectrum leaf rust seedling resistance gene ( LrS2427 ). Molecular analysis based on 35 K wheat breeder’s array revealed the maximum percentage of Ae. speltoides genome introgression on homoeologous group 2. In situ hybridization studies revealed the presence of S genome in Sel. 2427, showing six translocations on four chromosomes. Karyotyping using repetitive probe (AAG) 6 revealed that the two chromosomes involved are 2D and 2B. Genic regions causing gametocidal activity were identified by dissecting it into component traits and QTLs on 2D and 2B chromosomes were revealed in case of the trait seed shrivelling index. To break the inadvertent association of LrS2427 with gametocidal genes, F 1 (Agra Local X Sel. 2427) seeds were irradiated with gamma rays and stable leaf rust resistant mutants lacking gametocidal activity were developed. These mutants showed resistance to different races of leaf rust pathogen and showed superior agronomic performance as well. These mutants could be a great resource in wheat improvement for utilization of the leaf rust resistance gene LrS2427 without any yield penalty.