[Identification of a resistance gene to bacterial blight (Xanthomonas oryzae pv. oryzae) in a somaclonal mutant HX-3 of indica rice].
Using the mature embryo of a susceptible rice variety Minghui 63 as the explant, we have obtained a somaclonal mutant HX-3 through selection in vitro, which has showed resistance to bacterial blight. In 8 successive years, the resistance of R1 to R9 generations of HX-3 was identified by ZJ173, a typical bacterial blight strain in Yangtsu River valley, and the results showed that the resistance of HX-3 was stable and heritable. Genetic analysis also indicated that the resistance of HX-3 to bacterial blight was under a dominant gene controlling. Using 32 bacterial blight strains collected in China, Philippines and Japan, the resistance spectrum of HX-3 and other 13 testers with different major dominant resistance genes were tested. Results of 2 years (1999-2000) experiment showed that HX-3 had a broad resistance spectrum, which seemed to be different with those of the other dominant resistance genes identified. Allelic tests were also conducted by crossing HX-3 with IRBB4, IRBB7, CBB12 and IRBB21, and the F2 populations of each of the 4 crosses demonstrated resistant and susceptible plant segregation, indicating that the resistance gene in HX-3 different from Xa-4, Xa-7, Xa-12 and Xa-21. All these results proved that there was a new resistance gene in HX-3. We have designated the new gene as Xa-25(t).
Gao
Dong-Ying
DY
Institute of Agricultural Genetics and Phsiology, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China. ricebiot@jlonline.com
Xu
Zhi-Gang
ZG
Chen
Zhi-Yi
ZY
Sun
Li-Hua
LH
Sun
Qi-Ming
QM
Lu
Fan
F
Hu
Bai-Shi
BS
Liu
Yong-Feng
YF
D004198:Disease Susceptibility / Q000382:microbiology; D017343:Genes, Plant; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006824:Hybridization, Genetic / Q000235:genetics; D009154:Mutation; D012275:Oryza / Q000235:genetics* / Q000382:microbiology; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D030821:Plants, Genetically Modified; D014974:Xanthomonas / Q000235:genetics