Characterization and molecular mapping of stripe rust resistance in wheat – Psathyrostachys huashanica introgression line H9015-17-1-9-6

Abstract

Stripe rust (yellow rust), caused by Puccinia striiformis Westend. f. sp. tritici (Pst), is one of the most destructive fungal disease in wheat(Triticum aestivum L.). Growing resistant cultivars is the best strategy to control stripe rust. The wheat introgression line H9015-17–1-9–6 was developed from an interspecific hybridization between the common wheat cultivar 7182 and Psathrostachys huashanica Keng (2n = 2x = 14, NsNs). H9015-17–1-9–6 has all-stage resistance to all known Chinese stripe rust races, including three widely virulent races: CYR32, CYR33 and CYR34. To identify stripe rust resistance genes in the introgression line, H9015-17–1-9–6 was crossed with the susceptible genotype ‘Mingxian169' and the F1, F2, F3 and BC1 generations were inoculated with Pst races under controlled greenhouse conditions. The results indicated that a single dominant gene in H9015-17–1-9–6, temporarily designated as YrH9015, confers resistance to race CYR32. Using bulked segregant analysis methods, we identified seven resistance gene analogue polymorphism (RGAP) markers and three simple sequence repeat (SSR) markers associated with YrH9015 on the long arm of chromosome 5D. The genetic distances of the two closest flanking markers, namely M4 and M5, were 2.4 and 3.1 centimorgans, respectively. Based on the chromosomal location, reaction patterns and pedigree analysis, YrH9015 is likely a novel resistance gene. This gene and the flanking markers obtained from this study are expected to be useful in pyramiding YrH9015 with other Yr genes to develop wheat cultivars with high-level and durable resistance to stripe rust and may also benefit marker assisted selection (MAS) in breeding programmes.