甘蓝型油菜株高QTL定位及主效QTL区间候选基因预测

为了研究油菜株高的遗传基础,以2个甘蓝型油菜株系DH-7-9(矮杆)×DH-G-42(高杆)杂交后代连续自交的重组自交系群体(190个家系)为材料,在西宁和武汉2种环境下进行株高性状鉴定,结果显示,该重组自交系群体的株高表现连续变异并且符合正态分布。利用前期构建的遗传连锁图,结合2种环境下株高性状鉴定数据,采用Win QTLcart 2.5软件复合区间作图法(CIM)进行QTL定位和效应估计,结果表明,在2种环境下共检测到11个与株高性状相关的QTL,单个QTL可解释的表型变异为1.17%~10.45%。在A10连锁群上,主效QTL(q PH-X-A10或q PHW-A10)在两环境下可重复检测到,可解释10.24%~10.45%的表型变异。将156个拟南芥株高基因与该主效QTL置信区间对应的油菜基因组上的723个基因进行同源比较分析,在主效QTL区域内预测到2个株高候选基因Bna A10g07740D和Bna A10g12020D,其对应的拟南芥同源基因分别为ATGA20ox2、GA5/ATGA20ox1和STA1,均与拟南芥株高相关。

QTL Mapping of Plant Height and Prediction of Candidate Genes in Major QTL Interval of Brassica napus

For studying the genetic basis controlling the plant height of rapeseed (Brassica napus),a recombinant inbred line population(190 lines) derived from a cross between a dwarf B.napus line DH-7-9 and a tall B.napus line DH-G-42 constructed by selfing for successive generations was used as material.This population was grown in Xining and Wuhan.The plant heights of individual lines were measured.The QTLs of plant height were detected using the genetic map constructed before by the complex interval graph method (CIM) of WinQTLcart 2.5 software under two environments.The results showed that a total of 11 putative QTLs for plant height were detected under two environments,each of them explained 1.17％-10.45％ of phenotypic variation.In linkage group A10,one major QTL(qPH-X-A10 or qPH-W-A10) was identified under two environments repeatedly,explaining 10.24％-10.45％ of the phenotypic variation.We collected 156 genes associated with the plant height of Arabidopsis thaliana and then searched the genomic region corresponding to the major QTL confidence interval to screen the possible candidate genes in B.napus.Two candidate genes,BnaA10g07740D and BnaA10g12020D,associated with plant height were founded.They had three ortholcgous genes ATGA20ox2,GA5/ATGA20ox1 and STA1,all involving in plant height differentiation of A.thaliana.