水稻明恢826光身基因GL826的精细定位与候选基因分析OA北大核心CSTPCD

Glabrous rice is an important germplasm resource for practical utilization in hybrid rice breeding.Minghui 826(MH826),an excellent glabrous restorer line,was originated from the Sanming Academy of Agricultural Sciences.In the present study,we initially performed a comprehensive phenotypic characterization for MH826.Additionally,fine mapping and candidate gene analysis of the glabrous trait in MH826 were conducted.These results will provide essential information for the subsequent functional analysis and molecular mechanism of the glabrous gene in MH826.By scanning electron microscope,it was revealed that MH826 showed smooth leaves and hairless glumes under normal growth conditions,while the leaf trichomes,including macro and micro hairs,were severely deficient.To perform a genetic analysis,the F1 and F2 populations were generated by crossing MH826 with indica cultivars Huazhan,Minghui2155,and 9311,the latter of which produce leaves exhibiting distinct trichomes.The observation and statistical analysis of the leaf phenotypes in F1 and F2 plants showed that all F1 plants displayed hairy leaves.In the F2 populations,the leaf phenotype was segregated,and the segregation ratio of hairy to glabrous leaf was approximately 3∶1(χ2= 0.89,1.10,1.07<χ20.05=3.84),indicating that the glabrous phenotype of MH826 is controlled by a single recessive nuclear gene,which was designated as GL826(Glabrous Leaf 826).With 429 recessive F2 individuals derived from the cross between MH826 and Huazhan,the GL826 gene was finally fine-mapped to a narrow region between InDel-70 and InDel-11on the short arm of chromosome 5 through integrated bulked segregation analysis and recessive class analysis by Mpamaker/Exp 3.0 and MapDraw.The genetic distance between each of these markers was 0.2 cM which corresponds to a physical distance of 141.03 kb.Within this interval,totally 23 complete open reading frames were predicted.Among these,LOC_Os05g02730 is a known gene associated with the development of leaf trichomes in rice.However,we did not identify any base variation in both the coding and the promoter region of LOC_Os05g02730 between MH826 and several well-known rice cultivars(Huazhan,9311 and MH2155).The quantitative real-time PCR(qRT-PCR)analysis revealed that the expression levels of LOC_Os05g02730 were down-regulated in leaves,stems,and young panicles of MH826 during different growth stages.Taken together,LOC_Os05g02730 was proposed to be the candidate GL826 gene.This study provides a theoretical basis for further application of the glabrous restorer line MH826 and the GL826 gene in hybrid rice breeding.