Map positions of 47 Arabidopsis sequences with sequence similarity to disease resistance genes.
Map positions have been determined for 42 non-redundant Arabidopsis expressed sequence tags (ESTs) showing similarity to disease resistance genes (R-ESTs), and for three Pto-like sequences that were amplified with degenerate primers. Employing a PCR-based strategy, yeast artificial chromosome (YAC) clones containing the EST sequences were identified. Since many YACs have been mapped, the locations of the R-ESTs could be inferred from the map positions of the YACs. R-EST clones that exhibited ambiguous map positions were mapped as either cleavable amplifiable polymorphic sequence (CAPS) or restriction fragment length polymorphism (RFLP) markers using F8 (Ler x Col-0) recombinant inbred (RI) lines. In all cases but two, the R-ESTs and Pto-like sequences mapped to single, unique locations. One R-EST and one Pto-like sequence each mapped to two locations. Thus, a total of 47 loci were identified in this study. Several R-ESTs occur in clusters suggesting that they may have arisen via gene duplication events. Interestingly, several R-ESTs map to regions containing genetically defined disease resistance genes. Thus, this collection of mapped R-ESTs may expedite the isolation of disease resistance genes. As the cDNA sequencing projects have identified an estimated 63% of Arabidopsis genes, a very large number of R-ESTs (approximately 95), and by inference disease resistance genes of the leucine-rich repeat-class probably occur in the Arabidopsis genome.
Botella
M A
MA
Sainsbury Laboratory, John Innes Centre, Norwich NR4 7UH, UK.
Coleman
M J
MJ
Hughes
D E
DE
Nishimura
M T
MT
Jones
J D
JD
Somerville
S C
SC
D017360:Arabidopsis / Q000235:genetics*; D001483:Base Sequence; D002874:Chromosome Mapping / Q000379:methods; D018244:Chromosomes, Artificial, Yeast; D003433:Crosses, Genetic; D017343:Genes, Plant; D005819:Genetic Markers; D007113:Immunity, Innate; D008969:Molecular Sequence Data; D010935:Plant Diseases / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D011995:Recombination, Genetic; D016324:Sequence Tagged Sites
D005819:Genetic Markers