芝麻矮化主效QTL精细定位、基因克隆及功能鉴定

Sesame, Sesamum indicum L., is an ancient oil crop supplying special edible oil for Chinese. Increasing yield and resolving the contradiction between low yield and high input in sesame are the major challenge for modern agriculture. The development of "ideal plant type" has been proposed as a means to enhance sesame yield potential over that of existing varieties, which will be a new focus for sesame study. Decreasing plant height is the breakthrough point for developing sesame "ideal plant type". Based on the dwarf materials identified from the sesame germplasms, the present research will be performed to study the molecular factors controlling sesame plant height, so as to provide theoretical foundations and technology supports for the improvement of sesame plant type. According to the morphologic study of these dwarf materials, the height of first capsule and the number of capsule nodes were found to be the major factors in controlling sesame plant height, and all of them showed normal distribution in a sesame core collection. In this study, the super-BSA (bulked sergeant analysis) will be employed to study the population of F2 with 1215 individuals and their F2:3 family lines from a cross of dwarf and high sesame lines. In combination with the high-density linkage map and genome sequence of sesame, the genes responsible for the height of first capsule and the number of capsule nodes will be fine mapped and cloned, and these genes will be verified with association analysis by using their functional markers to screen a natural group. Finally, some valuable dwarf germplasms can be identified and provided for further applications. The project is a part of the post-genome study of sesame, as the genome sequencing has been completed by the institute of applicant, and the fundamental work of the project has been well done by far. The project and the methods including super-BSA and association analysis will be used for the first time in sesame, and the implement and completion of this project will be of great theoretical and applicable significance to the sesame study and breeding through the world.

芝麻是我国传统油料作物，单产水平较低，芝麻理想株型育种新方向的提出旨在提高芝麻单产，将引起品种改良研究新热点，改良高大品种是本研究的切入点。利用芝麻资源中的矮化品种解析控制株高矮化因素的相关基因分子基础，为株型改良提供理论和技术支持。对矮化与高杆品种表型考察表明控制矮化的因素主要是始蒴部位高度和有效果节节间长度。本项目用矮化×高杆1215株F2群体和F2:3家系，基于构建的芝麻高密度遗传连锁图谱和基因组物理图谱，结合生物信息学分析进行始蒴部位高度和有效果节节间长度QTL定位，对主效QTL进行克隆并开发功能标记，通过扫描核心种质群体和关联分析鉴定其功能，同时挖掘新的矮化基因资源。本项目围绕选题已做好前期工作准备，研究内容和采用的Super BSA、大规模自然群体关联分析等在国内外芝麻尚属首次，研究结果将对芝麻基础研究和育种改良具有重要理论和实际意义。

芝麻是我国传统油料作物，单产水平较低，芝麻理想株型育种新方向的提出旨在提高芝麻单产，将引起品种改良研究新热点，改良高大品种是本研究的切入点。利用芝麻资源中的矮化品种解析控制株高矮化因素的相关基因分子基础，为株型改良提供理论和技术支持。项目利用RAD-Seq (restriction-site associated DNA sequencing) 技术对构建的ZZM2748（矮杆） ×中芝13（高杆） F8重组自交系群体进行基因分型，构建了一张包含1522个分子标记的高密度遗传图谱，定位出芝麻株高、主茎始蒴高度、空稍尖长度、主茎果轴长度、有效果节数、节间长度等性状QTL41个，其中株高QTL10个，表型解释率变化在3–23%。并精细定位到同时控制株高、主茎始蒴高度、主茎果轴长度和有效果节数的矮化位点qPH-3.3，其对株高表型贡献率为18%。进一步分析发现，该位点SIN_1015931参与植物内源激素的调控，是调控芝麻株高发育的重要候选基因。研究成果为开展芝麻株型改良提供了基础理论支撑和基因资源。