Submitted to: Phytopathology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/8/2004
Publication Date: 9/1/2004
Citation: Agrama, H., Dahleen, L.S., Wentz, M., Jin, Y., Steffenson, B. 2004. Molecular mapping of the crown rust resistance gene rpc1 in barley. Phytopathology. Vol. 94:858-861. Interpretive Summary: Crown rust of barley, caused by Puccinia coronata var. hordei, is a new disease on barley. The disease is widely spread in the northern Great Plains of the United States and is a concern for causing yield and quality reductions in barley. This study utilized DNA markers to tag a crown rust resistance gene, Rpc1, and to map this gene to specific chromosome location. This information will be useful for geneticists and plant pathologists to study the host-plant pathogen interactions of the barley crown rust system and for breeders to utilize the markers to develop resistant varieties. The localization of Rpc1 is potentially useful for the map-based cloning of the Rpc1 gene.
Technical Abstract: Crown rust of barley, caused, by Puccinia coronata var. hordei, is sporadic and sometimes may cause yield and quality reductions in the Great Plains region of the United States and Canada. The incompletely dominant resistance allele Rpc1 confers barley resistance to P. coronata. Two generations, F2 and F2:3, developed from a cross between the resistant line Hor2596 (CIho 1243) and the susceptible line Bowman (PI483237) were used in this study. Bulked segregant analysis combined with random amplified polymorphic DNAs (RAPDs) were used to identify molecular markers linked to Rpc1. DNA genotypes for 500 RAPD primers, 200 microsatellites (SSRs), and 71 restriction fragment length polymorphisms (RFLPs) probes were applied to map Rpc1. Of these, 15 RAPD primers, 62 SSR markers and 32 RFLP markers identified polymorphisms between the resistant and susceptible parents. The polymorphic markers were applied to 97 F2 individuals and F2:3 families. These markers identified 112 polymorphisms and were used for primary linkage mapping to Rpc1 using Map Manager QT. Two RFLP and five SSR markers spanning the centromere on chromosome 3H, and one RAPD marker (O8_700) were linked with Rpc1, and thus used to construct a 30 cM linkage map containing the Rpc1 locus. The genetic distance between Rpc1 and the closest RAPD marker O8_700 was 2.5 cM. The linked markers will be useful for incorporating the crown rust resistance gene into barley breeding lines.