Résumé
A rust resistance gene is the target of a map-based cloning approach in a typical interspecific, highly polyploid, aneuploid sugarcane cultivar (Saccharum spp., 2n= ca 115). Earlier work based on conservation of synteny with sorghum and on Bulked Segregant Analysis allowed us to localize this gene at the extremity of one chromosome and to flank it with markers at 0.6 and 0.3 cM. We are now exploiting the sorghum physical map, the rice genome sequence and the sugarcane ESTs to reach the gene. We have built a sorghum BAC contig covering the homeologous target area in sorghum. We have identified the homeologous target area on the physical map of rice and compared the sequence of this region with a sugarcane EST data base. The cDNAs corresponding to the sugarcane EST showing homology with the rice sequence and the sorghum BAC end-clone were used to saturate the genetic map in the vicinity of the target gene and to build a sugarcane BAC contig covering the target area. (Texte intégral)