水稻幼苗耐Mn^(2+)胁迫的QTL及其互作检测

Analysis of QTLs with Additive and Epistasis Effects for Tolerance to High Mn^(2+)Stress at Seedling Stage in Rice

用珍汕97B/密阳46构建RIL(recombinant inbred line)群体及其遗传图谱,采用纸培法育苗和培养,以基本营养液为对照(CK),100 mg/L Mn^(2+)为胁迫处理,用培养20d的幼苗感Mn^(2+)指数[(对照苗高-处理苗高)/对照苗高×100]作为评价指标,进行耐Mn^(2+)胁迫的主效应和上位性效应QTL检测。结果表明,RIL群体幼苗生长受Mn^(2+)胁迫的抑制作用明显,株系间对其胁迫反应差异较大。试验共检测到2个与耐Mn^(2+)胁迫有关的主效应QTL (qRMC-5和qRMC-6-2),表型贡献率分别为6.03%和6.82%,耐Mn^(2+)胁迫有效基因均来自于父本密阳46。试验还对幼苗耐Mn^(2+)胁迫的上位性互作进行分析,检测到5对上位性效应QTL,涉及第1、2、3、6、7、9和10等7条染色体,总表型贡献率达28.69%,表明幼苗耐Mn^(2+)胁迫的上位性QTL不仅普遍存在,且对耐Mn^(2+)有良好的效果。

A recombinant inbred line （RIL） population derived from Zhenshan 97B/Miyang 46 （ZS97B/MY46） and its genetic linkage map were employed to map QTL controlling tolerance to high Mn^2＋ stress by treating the seedling with 100 mg/L MR^2＋ concentration. The relative changes of seedling height was taken as Mn^2＋ sensitivity index （SHMSI）, which is calculated as （seedling height at CK-seedling height at high Mn^2＋ stress）/seedling height at CK×100. The results indicated that high Mn^2＋concentration severely inhibited the seedling from growing. Different lines responded differently to the high Mn^2＋ stress. A total of two QTLs with significant additive effects conferring tolerance to high Mn^2＋ stress were detected, i.e. qRMC-5 and qRMC-6-2. These two QTLs could explain 6.03% and 6.82% of the total phenotypic variations, respectively. Both of tolerant effects came from male parent, i. e. Miyang 46. In addition, a total of five pairs of additive×additive epistasis QTLs were significant for high Mn^2＋ stress. All of five pairs could explain 28.69% of the total phenotypic variations. It is suggested that the epistasis effects should be common in controlling the tolerance to high Mn^2＋ stress in rice seedling.