Plant, Animal & Microbe Genomes X Conference

January 12-16, 2002
Town & Country Convention Center
San Diego, CA

Poster: Genome Sequencing & ESTs
            

ANALYSIS OF A CHROMOSOMAL REGION FROM RICE AND BARLEY

¹ Institute of Genetics & Crop Plant Research (IPK), Corrensstrasse 3, D-06466 Gatersleben, Germany

² TraitGenetics GmbH, Schwabeplan 1b, D-06466 Gatersleben, Germany

³ Institute of Genetics & Crop Plant Research (IPK), Corrensstrasse 3, D-06466 Gatersleben, Germany

⁴ Institute of Genetics & Crop Plant Research (IPK), Corrensstrasse 3, D-06466 Gatersleben, Germany

The Rh2 resistance gene confers dominant resistance to scald (Rhynchosporium secalis) in barley. The gene is located on barley chromosome 7H in the interval between RFLP markers PSR119 and R2869. Comparative mapping of rice and barley revealed conserved linkage and gene order between rice chromosome 6 and barley chromosome 7H. By screening a rice BAC library with markers PSR119 and R2869, two overlapping rice BACs 6P23 and 3H2 were selected. Homologous barley BACs were found by hybridising several rice probes prepared from BAC 6P23 to a barley BAC library. Two overlapping barley BACs were characterized and mapping of several barley probes derived from these BACs confirmed that rice BAC 6P23 and the barley BACs are derived from the homologous chromosomal regions. The two rice BACs have already been sequenced in the Rice Genome Project. The barley BAC contig was extended by primerwalking to four BACs spanning approximately 300 kb. Hybridisation of rice probes of three predicted genes within a 15 kb stretch to the barley BAC contig and primary sequencing Data revealed the presence of conserved gene regions flanked by large segments of repetitive DNA and retrotransposons. A detailed sequence comparison of the homologous rice and barley regions will show to what extend the colinearity between rice and barley can be exploited for positional cloning in general and whether genomic regions around disease resistance genes are conserved.