QTL mapping and epistasis analysis of brace root traits in maize
QTL mapping and epistasis analysis of brace root traits in maize
复制标题
玉米支撑根性状的QTL定位及上位性分析
DOI：
10.1007/s11032-011-9655-x
复制
发表时间：
2012-08-01
影响因子：
3.1
通讯作者：
Chen, Y. H.
中科院分区：
文献类型：
--
作者：
Ku, L. X.;Sun, Z. H.;Chen, Y. H.
根系构型是影响根系倒伏的主要因素，在高密度条件下，根系构型限制了产量的稳定性。总支撑根层数(TBRTN)和有效支撑根层数(EBRTN)是影响根倒伏的两个最重要的根构型性状。然而，这些特征背后的遗传机制仍然知之甚少。本研究利用201个重组自交系(RIL)和278个来自这些重组自交系的永生化F2(IF2)群体，在3种环境下对TBRTN和EBRTN的数量性状基因座(QTL)进行了定位。在重组自交系和IF2群体中分别检测到10个QTL和15个QTL。在这两个群体中，我们发现了两个与TBRTN相同的主效QTL和一个相同的EBRTN主效QTL。TBRTN的QTL加性效应最大，对RILS和IF2群体表型变异的贡献率分别为16.36%和17.88%。除4号染色体外，所有玉米染色体都存在上位性效应。大多数上位性效应涉及位于不同染色体上的多对基因座。同时，我们发现了与其他几个基因座同时相互作用影响性状表达的基因座，这在IF2群体中尤为明显。例如，qTAR1-2同时与qTAR2-1、qTAR3-1、qTAR5-1和qITAR8-2相互作用，影响TBRTN的表达。因此，在玉米中发现了一个控制这些性状的复杂网络。这些结果为理解控制根系构型的分子机制提供了有用的信息。
Root architecture is a major factor influencing root lodging, which limits greater yield stability at high planting density. Total brace root tier number (TBRTN) and effective brace root tier number (EBRTN) are the two most important root architecture traits influencing root lodging. However, the genetic mechanisms that underlie these traits remain poorly understood. In this study, quantitative trait loci (QTL) for TBRTN and EBRTN were mapped using a set of 201 recombinant inbred lines (RILs) and 278 immortalized F2 (IF2) populations derived from these RILs, which were evaluated in three environments. Ten QTL in the RILs and 15 QTL in the IF2 population were detected. In the two populations, we identified two coincident major QTL for TBRTN and a single identical major QTL for EBRTN. The QTL for TBRTN showed the largest additive effect, accounting for 16.36 and 17.88% of the phenotypic variance in the RILs and IF2 population, respectively. Additional epistatic effects were identified for all the maize chromosomes, except for chromosome 4. Most epistatic effects involved pairs of loci that were on different chromosomes. At the same time, we found loci that interacted simultaneously with several other loci to affect expression of the traits, which was particularly evident in the IF2 population. For example,qTAR1-2interacted simultaneously withqTAR2-1,qTAR3-1,qTAR5-1, andqITAR8-2to affect the expression of TBRTN. Therefore, a complex network controlling the traits was found in maize. These results provide useful information for understanding the molecular mechanisms controlling root architecture.