Identification and gene prediction of a 24 kbregion containing xa5,a recessive bacterial blight resistance gene in rice(Oryza sativa L.)  

作　　者：ZHONGYiming JIANGGuanghuai CHENXuewei XIAZhihui LIXiaobing ZHULihuang ZHAIWenxue 

机构地区：[1]InstituteofGeneticsandDevelopmentalBiology,ChineseAcademyofSciences,Beijing100101,China [2]CollegeofLifeSciences,UniversityofScienceandTechnologyofChina,Hefei230026,China

出　　处：《Chinese Science Bulletin》2003年第24期2725-2729,共5页

基　　金：supported by the Nationa1 Key Basic Research Program of China(Grant No.G1998010207);the Nationa1 Natural Science Foundation of China(Grant No.30270747);the Nationa1 Special Program on Transgenic plants(Grant No.JY03A0501).

摘　　要：Rice xa5 gene provides recessive, race-specific resistance to bacterial blight disease caused by the pathogen Xanthomonas oryzae pv. oryzae and has great value for re-search and breeding. In an effort to clone xa5, an F2 popula-tion of 4892 individuals was developed from the xa5 near isogenic lines, IR24 and IRBB5. A fine mapping procedure was conducted and tightly linked RFLP markers were used to screen a BAC library of IRBB56, a resistant rice line con-taining the xa5 gene. A 213 kb contig covering the xa5 locus was constructed. According to the sequences from the Inter-national Rice Genome Sequening Project (IRGSP), the Chi-nese Superhybrid Rice Genome Project (SRGP) and some sub-clones of the contig, twelve SSLP and CAPS markers were developed for fine mapping. The xa5 gene was mapped to a 0.3 cM interval between markers K5 and T4, which spanned an interval of approximately 24 kb, co-segregating with marker T2. Sequence analysis of the 24 kb region re-vealed that an ABC transporter and a basal transcription factor (TFIIa) were potential candidates for the xa5 resis-tance gene product. The molecular mechanism by which the xa5 gene provides recessive, race-specific resistance to bacte-rial blight will be elucidated by the functional tests of the 24 kb DNA and the candidate genes.Rice xa5 gene provides recessive, race-specific resistance to bacterial blight disease caused by the pathogen Xanthomonas oryzae pv. oryzae and has great value for re-search and breeding. In an effort to clone xa5, an F2 popula-tion of 4892 individuals was developed from the xa5 near isogenic lines, IR24 and IRBB5. A fine mapping procedure was conducted and tightly linked RFLP markers were used to screen a BAC library of IRBB56, a resistant rice line con-taining the xa5 gene. A 213 kb contig covering the xa5 locus was constructed. According to the sequences from the Inter-national Rice Genome Sequening Project (IRGSP), the Chi-nese Superhybrid Rice Genome Project (SRGP) and some sub-clones of the contig, twelve SSLP and CAPS markers were developed for fine mapping. The xa5 gene was mapped to a 0.3 cM interval between markers K5 and T4, which spanned an interval of approximately 24 kb, co-segregating with marker T2. Sequence analysis of the 24 kb region re-vealed that an ABC transporter and a basal transcription factor (TFIIa) were potential candidates for the xa5 resis-tance gene product. The molecular mechanism by which the xa5 gene provides recessive, race-specific resistance to bacte-rial blight will be elucidated by the functional tests of the 24 kb DNA and the candidate genes.

关 键 词：细菌疫病 抗病性基因 稻 DNA 

分 类 号：S511[农业科学—作物学]