title: A new finely mapped Oryza australiensis-derived QTL in rice confers resistance to brown planthopper.
abstract: Brown planthopper (BPH) is the most destructive pest of rice in Asia. The BPH resistance in the introgression line IR65482-17-511-5-7 (IR65482-17) is derived from the wild rice species Oryza australiensis. An F2:3 population from a cross between Zhenshan 97 (ZS97) and IR65482-17 was used to map three quantitative trait loci (QTLs) for seedling resistance and feeding rate to BPH. The loci were distributed on chromosomes 2, 4 and 12. The QTL qBph4.2 on chromosome 4 had the largest effect, and contributed 36-44% of the phenotypic variance with a LOD score of 19-29. To validate the effect of qBph4.2, two near-isogenic lines (NILs) containing the qBph4.2 locus in the backgrounds of ZS97 and 9311 were developed by marker-assisted backcrossing (MABC). BPH bioassays showed that lines homozygous for the IR65482-17 allele (NIL+) of qBph4.2 tented to have significantly higher seedling resistance to BPH than those homozygous for the ZS97 or 9311 alleles (NIL-). Resistance was associated with a lower feeding rate by the insect. qBph4.2 was delimited to a ~300 kb (0.04 cM) region flanked by markers RM261 and S1, and co-segregating with XC4-27. This study will facilitate map-based cloning and marker-assisted selection of the gene, and permits further studies of gene function and resistance mechanisms in rice: BPH interaction.
authors: National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, PR China.
authors: Jie
authors: J
authors: Hu
authors: National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, PR China.
authors: Cong
authors: C
authors: Xiao
authors: National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, PR China.
authors: Ming-Xing
authors: MX
authors: Cheng
authors: National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, PR China.
authors: Guan-Jun
authors: GJ
authors: Gao
authors: National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, PR China.
authors: Qing-Lu
authors: QL
authors: Zhang
authors: National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, PR China. Electronic address: yqhe@mail.hzau.edu.cn.
authors: Yu-Qing
authors: YQ
authors: He
mesh_terms: D000818:Animals; D002874:Chromosome Mapping; D003433:Crosses, Genetic; D017343:Genes, Plant; D006430:Hemiptera; D012275:Oryza / Q000235:genetics* / Q000276:immunology*; D010572:Pest Control, Biological; D010935:Plant Diseases / Q000276:immunology; D040641:Quantitative Trait Loci; D036226:Seedlings / Q000276:immunology*
keywords: Brown planthopper resistance gene; Oryza australiensis; QTL mapping