甘蓝型油菜茎高QTL定位及株高相关位点整合

Detection of stem height QTL and integration of the loci for plant height-related traits in B. napus

甘蓝型油菜主茎高度(茎高)是株型的构成因子之一,研究其遗传机理对油菜株型改良具有重要的理论指导意义。目前对甘蓝型油菜茎高研究的报道较少。本研究以2个油菜茎高差异较大的亲本构建的重组自交系群体为材料,利用SNP高密度遗传图谱,2年共检测到11个茎高QTL,分布在A04、A06、C04、A08和C01染色体上,位点的表型贡献率为7.25%~19.61%。同时,以455份来源不同的甘蓝型油菜为材料,结合重测序产生的SNP标记,对茎高进行全基因组关联分析,2年共检测到5个SNP与茎高性状显著关联,分布在A08、A10、C02和C06染色体上。根据茎高定位结果,找到一些与激素途径(生长素、赤霉素和油菜素内酯)、光形态建成及植物生长发育相关的候选基因。在此基础上,结合国内外株高相关性状定位研究结果,将株高相关性状位点整合到甘蓝型油菜参考基因组上,发现4个以上群体都在A01、A03、A07、C03和C06染色体上找到株高定位的区间,2个群体在A10染色体上找到主花序长度共同定位的区间,在A02和C03染色体上找到一次分枝高度共同定位的区间。本研究中的茎高定位结果与整合后的株高相关性状QTL定位区间有部分重叠,位于A04、A06、A08、C04和C06染色体上。上述结果为甘蓝型油菜理想株型育种提供了理论依据。

Stem height(SH)is important for the plant architecture and yield in Brassica napus.To date,the research about stem height in B.napus is very less.In the study,QTL mapping of stem height in B.napus was performed using the high density SNP genetic map constructed from the recombinant inbred lines(RIL)population with Illumina 60K SNP array.Totally 11 QTLs were detected in two years on A04,A06,C04,A08,and C01,which explained 7.25%-19.61%of the phenotypic variation.In addition,genome-wide association analysis(GWAS)of stem height in the 455 B.napus genotyped by resequencing was performed,and five significantly associated SNP loci on A08,A10,C02,and C06 were identified.And the candidate genes involved in photomorphogenesis,plant growth and development,and hormone pathway such as auxin,gibberellin and brassinosteroid were identified.We also integrated the loci for plant height-related traits including plant height(PH),main inflorescence length(MIL),branch segment(BS)and branch initiation height(BIH)in B.napus,in which four loci for PH on A01,A03,A07,C03,and C06 were identified in at least four populations,one locus for MIL on A10 and two loci for BIH on A02 and C03 were identified in two populations.The loci for stem height in our study were consistent with pervious QTL mapping results for plant height,branch initiation height and main inflorescence length.This study lays a foundation for the breeding of plant architecture in B.napus.