Studies that investigated the genetic basis of source and sink related traits have been widely conducted.However, the vascular system that links source and sink received much less attention. When maize was domesticate...Studies that investigated the genetic basis of source and sink related traits have been widely conducted.However, the vascular system that links source and sink received much less attention. When maize was domesticated from its wild ancestor, teosinte, the external morphology has changed dramatically; however, less is known for the internal anatomy changes. In this study, using a large maize-teosinte experimental population, we performed a high-resolution quantitative trait locus（QTL） mapping for the number of vascular bundle in the uppermost internode of maize stem.The results showed that vascular bundle number is dominated by a large number of small-effect QTLs, in which a total of 16 QTLs that jointly accounts for 52.2% of phenotypic variation were detected, with no single QTL explaining more than 6% of variation. Different from QTLs for typical domestication traits, QTLs for vascular bundle number might not be under directional selection following domestication.Using Near Isogenic Lines（NILs） developed from heterogeneous inbred family（HIF）, we further validated the effect of one QTL qVb9-2 on chromosome 9 and fine mapped the QTL to a 1.8-Mb physical region. This study provides important insights for the genetic architecture of vascular bundle number in maize stem and sets basis for cloning of qVb9-2.展开更多
文摘低温会影响水稻正常的生长和发育,增强耐冷性已成为水稻育种的主要目标之一.为了鉴定和定位水稻耐冷性相关位点,本研究以广陆矮4号（受体）与日本晴（供体）杂交获得的染色体片段代换系群体中的1个低温敏感株系C32022为材料,测定低温处理后植株存活率,采用代换作图法在水稻第3染色体上定位一个控制水稻苗期耐冷性的QTL,命名为qCTS3-1.利用C32022和广陆矮4号衍生的F2分离群体进行遗传分析,结果显示,该群体中叶片表现正常绿色与叶片表现出黄色、萎蔫单株比例符合1∶3分离比,表明耐冷性受单个主效QTL控制.来自日本晴的等位基因能够增加植株对低温的敏感性.利用该群体中86个隐性单株将qCTS3-1初步定位在分子标记WZD-S3-7～WZD-S3-11,物理距离约为550 kb.
基金supported by the National Hi-Tech Research and Development Program of China(2012AA10A307)National Natural Science Foundation of China(31322042)+1 种基金the Recruitment Program of Global Expertsthe Fundamental Research Funds for the Central Universities
文摘Studies that investigated the genetic basis of source and sink related traits have been widely conducted.However, the vascular system that links source and sink received much less attention. When maize was domesticated from its wild ancestor, teosinte, the external morphology has changed dramatically; however, less is known for the internal anatomy changes. In this study, using a large maize-teosinte experimental population, we performed a high-resolution quantitative trait locus（QTL） mapping for the number of vascular bundle in the uppermost internode of maize stem.The results showed that vascular bundle number is dominated by a large number of small-effect QTLs, in which a total of 16 QTLs that jointly accounts for 52.2% of phenotypic variation were detected, with no single QTL explaining more than 6% of variation. Different from QTLs for typical domestication traits, QTLs for vascular bundle number might not be under directional selection following domestication.Using Near Isogenic Lines（NILs） developed from heterogeneous inbred family（HIF）, we further validated the effect of one QTL qVb9-2 on chromosome 9 and fine mapped the QTL to a 1.8-Mb physical region. This study provides important insights for the genetic architecture of vascular bundle number in maize stem and sets basis for cloning of qVb9-2.
