title: Identification of a 47-kb DNA fragment containing Xa4, a locus for bacterial blight resistance in rice.
abstract: Bacterial blight caused by Xanthomonas oryzae pv oryzae is a devastating disease in rice worldwide. The resistance gene Xa4 has been widely used in breeding programs and played an important role in protecting rice from this disease. Using 642 highly susceptible individuals and a random sample of 255 individuals from an F(2) population developed from a cross between IRBB4 and IR24, the Xa4 gene was genetically mapped to a region less than 1 cM. A contig map was constructed for the Xa4 region consisting of six non-redundant bacterial artificial chromosome (BAC) clones and spanning approximately 500 kb in length. Analysis of recombination events in the Xa4 region located the gene locus to one BAC, 3H8. Assay of the recombinants using the subclones of 3H8 in combination with sequence analysis further narrowed the Xa4 locus down to a 47-kb fragment.
authors.affiliation: National Key Laboratory of Crop Genetic Improvement, National Center of Crop Molecular Breeding, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: X
authors.initials: X
authors.lastname: Sun
authors.forename: Z
authors.initials: Z
authors.lastname: Yang
authors.forename: S
authors.initials: S
authors.lastname: Wang
authors.forename: Q
authors.initials: Q
authors.lastname: Zhang
mesh_terms: D002874:Chromosome Mapping; D022202:Chromosomes, Artificial, Bacterial; D003001:Cloning, Molecular; D020451:Contig Mapping; D003433:Crosses, Genetic; D004247:DNA / Q000378:metabolism; D015723:Gene Library; D017343:Genes, Plant; D005838:Genotype; D007113:Immunity, Innate / Q000235:genetics*; D008957:Models, Genetic; D009693:Nucleic Acid Hybridization; D012275:Oryza / Q000235:genetics* / Q000382:microbiology; D020161:Physical Chromosome Mapping; D010935:Plant Diseases; D011995:Recombination, Genetic; D014974:Xanthomonas / Q000378:metabolism
chemical_list: D004247:DNA