Polysora rust (Southern Corn Rust) is a majordisease of maize in tropical and subtropical regioncausing yield loss in excess of 45%. The loci governingresistance (Rpp9, RppQ and RppD) have been mapped to10.01 bins on short arm of maize chromosome 10, whichalso has genes for common rust resistance like Rp1 andRp5. With the publication of maize draft genomicsequence we tried to annotate the region spanning thesegenes using comparative genomic tools. We constructed aphysical map using the various loci and thecorresponding markers, BAC clones and contigs reportedfrom the previous researchers and using MaizeGDB. Thesequence for this region was downloaded frommaizesequence.org. The sequence was scanned for codingregions using GENSCAN and the CDS and peptidesobtained along with the whole sequence (in bits of 1 MB)was subjected to BLAST analysis in NCBI-nBLAST,NCBI-pBLAST, COGE-BLAST and MaizeGDB BLAST.The region when located on a physical map, had all theloci governing Polysora rust resistance in a overlappingposition and was around 3 MB size. Two loci RppQ andRppD covered large portion of the 3MB region whereasRpp9 was 82769 bp long. The BLAST results indicatedthe similarity of the region to many loci responsible fordisease resistance like PR protein, Serine/threoninekinase protein, rust resistance protein (rp3-1), receptorkinases and zein cluster. The region shared homologywith rice, sorghum and brachypodium grass and wefound some orthologs having NB-LRR domain. Hencefrom this analysis it could be concluded that the region isresponsible for disease resistance and host many othergenes linked with resistance to various diseases
