Plant, Animal & Microbe Genomes X Conference

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

Poster: Genome Sequencing & ESTs
            

ANALYSIS OF 106 KB OF CONTIGUOUS DNA SEQUENCE FROM AEGILOPS TAUSCHII CHROMOSOME 1DS REVEALS HIGH GENE DENSITY AND A COMPLEX ARRANGEMENT OF GENES RELATED TO DISEASE RESISTANCE

¹ Department of Plant Pathology, Kansas State University, Manhattan, KS 66506

² USDA-ARS, Plant Science and Entomology Unit, Kansas State University, Manhattan, KS 66506

Vast differences exist in genome sizes of higher plants, however gene count remains relatively constant among species. Differences observed in DNA content can be attributed to retroelement amplification leading to genome expansion. Cytological and genetic studies have demonstrated that genes are clustered in islands, rather than distributed at random in the genome. Analysis of gene islands within highly repetitive genomes of plants such as wheat remains largely unstudied. The objective of our work was to sequence and characterize a contiguous DNA sequence from chromosome 1DS of Aegilops tauschii. An RFLP probe that maps to the Lr21/40 region of 1DS was used to isolate a single BAC. The BAC was sequenced and is 106 Kb in length. The contiguous DNA sequence contains a 54 Kb retroelement free gene island containing 9 open reading frames. Within the gene island is a complex arrangement of 2 resistance and 2 defense response genes. Gene density in this BAC is 1 gene per 6.7 Kb. This report demonstrates that wheat and its relatives do contain regions with gene densities similar to that of Arabidopsis.