Isolation, fine mapping and expression profiling of a lesion mimic genotype, spl(NF4050-8) that confers blast resistance in rice.
We evaluated a large collection of Tos17 mutant panel lines for their reaction to three different races of Magnaporthe oryzae and identified a lesion mimic mutant, NF4050-8, that showed lesions similar to naturally occurring spl5 mutant and enhanced resistance to all the three blast races tested. Nested modified-AFLP using Tos17-specific primers and southern hybridization experiments of segregating individuals indicated that the lesion mimic phenotype in NF4050-8 is most likely due to a nucleotide change acquired during the culturing process and not due to Tos17 insertion per se. Inheritance and genetic analyses in two japonica × indica populations identified an overlapping genomic region of 13 cM on short arm of chromosome 7 that was linked with the lesion mimic phenotype. High-resolution genetic mapping using 950 F(3) and 3,821 F(4) plants of NF4050-8 × CO39 delimited a 35 kb region flanked by NBARC1 (5.262 Mb) and RM8262 (5.297 Mb), which contained 6 ORFs; 3 of them were 'resistance gene related' with typical NBS-LRR signatures. One of them harbored a NB-ARC domain, which had been previously demonstrated to be associated with cell death in animals. Microarray analysis of NF4050-8 revealed significant up-regulation of numerous defense/pathogenesis-related genes and down-regulation of heme peroxidase genes. Real-time PCR analysis of WRKY45 and PR1b genes suggested possible constitutive activation of a defense signaling pathway downstream of salicylic acid but independent of NH1 in these mutant lines of rice.
National Institute of Agrobiosciences (NIAS), Tsukuba, Ibaraki, Japan. r.babu@cgiar.org
Raman
R
Babu
Chang-Jie
CJ
Jiang
Xin
X
Xu
Kameswara Rao
KR
Kottapalli
Hiroshi
H
Takatsuji
Akio
A
Miyao
Hirohiko
H
Hirochika
Shinji
S
Kawasaki
D000483:Alleles; D020090:Chromosome Segregation / Q000235:genetics; D032461:Chromosomes, Plant / Q000235:genetics; D003433:Crosses, Genetic; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D015723:Gene Library; D017343:Genes, Plant / Q000235:genetics*; D008040:Genetic Linkage; D056426:Genetic Loci / Q000235:genetics; D005838:Genotype; D007113:Immunity, Innate / Q000235:genetics*; D040582:Inheritance Patterns / Q000235:genetics; D007564:Japan; D020082:Magnaporthe / Q000502:physiology*; D058977:Molecular Sequence Annotation; D016254:Mutagenesis, Insertional / Q000235:genetics; D009154:Mutation / Q000235:genetics; D009711:Nucleotides / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D012275:Oryza / Q000235:genetics* / Q000276:immunology / Q000382:microbiology; D020161:Physical Chromosome Mapping; D010935:Plant Diseases / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D012038:Regeneration / Q000235:genetics; D046509:Tissue Culture Techniques
D009711:Nucleotides