Plant Physiol, March 2001, Vol. 125, pp. 1236-1247
Sequence Haplotypes Revealed by Sequence-Tagged Site Fine Mapping
of the Ror1 Gene in the Centromeric Region of Barley
Chromosome 1H1,[w]
Nicholas C.
Collins,2
Thomas
Lahaye,23
Christoph
Peterhänsel,
Andreas
Freialdenhoven,
Margaret
Corbitt, and
Paul
Schulze-Lefert*
Sainsbury Laboratory, John Innes Centre, Colney Lane, Norwich,
Norfolk NR4 7UH, United Kingdom (N.C., T.L., M.C.);
Rheinisch-Westfälische Technische Hochschule Aachen, Institut
für Biologie I, Worringer Weg 1, D-52074 Aachen, Germany (C.P.);
and Max-Planck-Institut für Züchtungsforschung, Abteilung
Biochemie, Carl-von-Linne-Weg 10, D-50829 Köln, Germany (A.F.,
P.S.-L.)
We describe the development of polymerase chain reaction-based,
sequence-tagged site (STS) markers for fine mapping of the barley
(Hordeum vulgare) Ror1 gene required for
broad-spectrum resistance to powdery mildew (Blumeria
graminis f. sp. hordei). After locating
Ror1 to the centromeric region of barley chromosome 1H
using a combined amplified fragment length
polymorphism/restriction fragment-length polymorphism (RFLP)
approach, sequences of RFLP probes from this chromosome region of
barley and corresponding genome regions from the related grass species
oat (Avena spp.), wheat, and Triticum
monococcum were used to develop STS markers. Primers based on
the RFLP probe sequences were used to polymerase chain reaction-amplify
and directly sequence homologous DNA stretches from each of four
parents that were used for mapping. Over 28,000 bp from 22 markers were
compared. In addition to one insertion/deletion of at least 2.0 kb, 79 small unique sequence polymorphisms were observed, including 65 single
nucleotide substitutions, two dinucleotide substitutions, 11 insertion/deletions, and one 5-bp/10-bp exchange. The frequency of
polymorphism between any two barley lines ranged from 0.9 to 3.0 kb,
and was greatest for comparisons involving an Ethiopian landrace.
Haplotype structure was observed in the marker sequences over distances
of several hundred basepairs. Polymorphisms in 16 STSs were used to
generate genetic markers, scored by restriction enzyme digestion or by
direct sequencing. Over 2,300 segregants from three populations were
used in Ror1 linkage analysis, mapping
Ror1 to a 0.2- to 0.5-cM marker interval. We discuss the
implications of sequence haplotypes and STS markers for the generation
of high-density maps in cereals.
1
This work was sponsored by the Gatsby Charitable Foundation.
2
These authors contributed equally.
3
Present address: Institute of Genetics, Martin Luther
Universität, Halle Weinbergweg 22, D-06120 Halle (Saale), Germany.
[w]
The online version of this article contains Web-only
data. The supplemental material is available at www.plantphysiol.org.
*
Corresponding author; e-mail schlef{at}mpiz-koeln.mpg.de; fax
49-221-5062-353.
© 2001 American Society of Plant Physiologists
