Inheritance and Linkage of Virulence Genes of Puccinia striiformis f. sp. hordei

Puccinia striiformis f. sp. hordei (Psh) causing barley stripe rust has only recently been known to be heteroecious, for which reason the inheritance of its virulence has not been analyzed. Herein, we selfed a Psh isolate, XZ-19-972, on Berberis aggregata and obtained 53 progenies. The virulence phenotypes (VPs) for these progenies were identified on 11 barley differentials, and their genotypes were assessed with 22 Kompetitive allele specific PCR-single nucleotide polymorphism (KASP-SNP) markers. In total, 18 VPs were detected among progenies, 17 (VP2-VP18) of which, corresponding to 43 isolates, were different from the parental isolate showing VP1. Of the 53 progenies, 8 exhibited increased virulence and 34 decreased virulence. One progeny, belonging to VP18, showed a different virulence formula but without a virulence increase or decrease. The parental isolate and all progenies were avirulent to yrc6 but virulent to yrc7. The parental isolate was heterozygous in terms of avirulence/virulence to nine barley resistance gene loci. KASP-SNP marker analysis identified 36 multilocus genotypes, based on which a linkage map was constructed, with total genetic distance intervals of 516.07 cM, spanning 16 avirulence or virulence loci. Taken together, our results provide important insights into the inheritance and virulence diversity of Psh.