Browsing by Subject "Puccinia hordei"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Amplified fragment length polymorphism and virulence polymorphism in Puccinia hordei
    (Canadian Journal of Plant Pathology, 2007) Sun, Y; Neate, S.M.; Zhong, S; Steffenson, Brian; Friesen, T. L.
    Puccinia hordei is the causal agent of barley leaf rust. To study the genetic diversity in P. hordei, 45 isolates with diverse virulence patterns and geographical origins were analyzed using amplified fragment length polymorphism markers. Two pathotypes of Puccinia graminis f. sp. tritici and one isolate of P. graminis f. sp. secalis were included in the analysis for comparison. Six primer-pair combinations of amplified fragment length polymorphism were used and a total of 782 polymorphic markers were generated. Cluster analysis showed that P. graminis f. sp. tritici and P. graminis f. sp. secalis were distinctly different from P. hordei. The P. hordei isolates were clustered into five groups: group I contained a single, rare isolate that was virulent on all resistance genes except Rph13 and Rph15 ; group II contained a single isolate found to be virulent on the resistance gene Rph15 ; group III contained 2 isolates; group IV contained 24 isolates, 11 from the United States and 13 from diverse locations around the world; and group V contained 17 isolates, 7 from California, 7 from other states of United States, and 3 from central Europe. The study revealed that molecular diversity in P. hordei can be associated with virulence, but not well with geographic origin.
  • Thumbnail Image
    Item
    Identification and mapping of a leaf rust resistance gene in barley line Q21861
    (Genome, 1997) Steffenson, Brian; Borovkova, I.G.; Jin, Y.; Kilian, A.; Blake, T.K.; Kleinhofs, A.
    Barley line Q21861 possesses an incompletely dominant gene (RphQ) for resistance to leaf rust caused by Puccinia hordei. To investigate the allelic and linkage relations between RphQ and other known Rph genes, F2 populations from crosses between Q21861 and donors of Rph1 to Rph14 (except for Rph8) were evaluated for leaf rust reaction at the seedling stage. Results indicate that RphQ is either allelic with or closely linked to the Rph2 locus. A doubled haploid population derived from a cross between Q21861 and SM89010 (a leaf rust susceptible line) was used for molecular mapping of the resistance locus. Bulked segregant analysis was used to identify markers linked to RphQ, using random amplified polymorphic DNAs (RAPDs), restriction fragment length polymorphisms (RFLPs), and sequence tagged sites (STSs). Of 600 decamer primers screened, amplified fragments generated by 9 primers were found to be linked to the RphQ locus; however, only 4 of them were within 10 cM of the target. The RphQ locus was mapped to the centromeric region of chromosome 7, with a linkage distance of 3.5 cM from the RFLP marker CDO749. Rrn2, an RFLP clone from the ribosomal RNA intergenic spacer region, was found to be very closely linked with RphQ, based on bulked segregant analysis. An STS marker, ITS1, derived from Rrn2, was also closely linked (1.6 cM) to RphQ.