通过构建单染色体片段代换系验证水稻细菌性条斑病抗性QTL qBlsr3d

Verification of QTL qBlsr3d Conferring Resistance to Bacterial Leaf Streak in Rice by Constructing SSSL

单染色体片段代换系是QTL精细定位的理想材料。水稻对细菌性条斑病的抗性属于典型的数量抗性。本研究以课题组构建的携有多个细条病抗性QTL(qBlsr3d,qBlsr5a和qBlsr5b)的近等基因系H359R为供体亲本,以感病品种H359为受体亲本,通过杂交,多次回交和自交,并结合分子标记辅助选择,成功构建了仅携有QTL qBlsr3d的单染色体片段代换系,命名为H359-BLSR3D。进一步通过分子标记定位分析表明:渗入区段位于第3号染色体分子标记3DSSR3和3DSSR12之间,物理距离约为1 250 kb。田间接种鉴定表明:H359-BLSR3D与感病亲本H359间的细条病抗性差异显著,结果证明了抗性QTL qBlsr3d的真实存在。H359-BLSR3D将为QTL qBlsr3d的精细定位和最终克隆奠定基础。

Chromosome segment substitution line （CSSL） is an ideal material for fine mapping of QTL. Bacterial leaf steak （BLS） resistance in rice is quantitatively inherited. In the present study, using near-isogenic lines H359R with multi-resistant QTLs （qBlsr3d, qBlsr5a, qBlsrSb） as the donor parent （constructed by our group previous） and H359 as the recurrent parent, by cross, back-cross, self-cross and marker-based selection, single segment substitution line （SSSL） with qBlsr3d was developed. Further mapping showed that： the target fragment is located within a 1 250 kb region between markers 3DSSR3 and 3DSSR12 on chromosome 3. Inoculation experiment showed that the resistrance was statistically significant between H359-BLSR3D and H359, the result testify that QTL qBlsr3d is truly exsit. H359-BLSR3D would provide the basis for QTL qBlsr3d fine mapping and its final cloning.