中国农业大学教授李建生及其合作者，首次在全基因组水平上对玉米籽粒油分的遗传基础进行了深入解析。相关成果日前在线发表于《自然—遗传学》杂志。
玉米是我国第一大粮食作物。油分是玉米籽粒最重要的营养成分之一，其能量密度和价值显着高于淀粉。普通玉米中油分含量一般为4%，经过人工不断选育后的高油玉米材料油分含量可达到20%。但目前在全基因水平上，高油玉米形成的遗传基础尚不明确。
来自中国农业大学与华中农业大学、中国农科院、深圳华大基因、美国农业部的研究人员，利用包括高油玉米在内的368份玉米自交系为材料，通过RNA测序获得了100多万个单核苷酸多态性位点，并利用全基因组关联分析方法，对籽粒油分相关性状进行了分析，共发现74个基因与籽粒总油分及组分显着关联，其中三分之一是编码油脂代谢的关键酶基因，包括26个与玉米籽粒总含油量显着相关的基因，这些基因可解释总油分83%的表型变异。
研究发现，人工长期选择的高油玉米仅在有限基因组位点发生改变，有利等位基因的累加可能是高油玉米油分增加的主要原因。
相关专家表示，该研究为剖析玉米籽粒油分形成的遗传结构提供了理论基础，对进一步改良玉米油分的含量和质量有重要指导意义。不过，揭示关键基因的作用机制还有待于更细致的研究，同时将这些研究成果最终应用于高油玉米的培育，仍有很多工作要做。(生物谷Bioon.com)
doi:10.1038/ng.2484
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Genome-wide association study dissects the genetic architecture of oil biosynthesis in maize kernels
Hui Li, Zhiyu Peng, Xiaohong Yang, Weidong Wang, Junjie Fu, Jianhua Wang, Yingjia Han,Yuchao Chai, Tingting Guo, Ning Yang, Jie Liu, Marilyn L Warburton, Yanbing Cheng,Xiaomin Hao, Pan Zhang, Jinyang Zhao, Yunjun Liu, Guoying Wang, Jiansheng Li & Jianbing Yan
Maize kernel oil is a valuable source of nutrition. Here we extensively examine the genetic architecture of maize oil biosynthesis in a genome-wide association study using 1.03 million SNPs characterized in 368 maize inbred lines, including 'high-oil' lines. We identified 74 loci significantly associated with kernel oil concentration and fatty acid composition (P < 1.8 × 10−6), which we subsequently examined using expression quantitative trait loci (QTL) mapping, linkage mapping and coexpression analysis. More than half of the identified loci localized in mapped QTL intervals, and one-third of the candidate genes were annotated as enzymes in the oil metabolic pathway. The 26 loci associated with oil concentration could explain up to 83% of the phenotypic variation using a simple additive model. Our results provide insights into the genetic basis of oil biosynthesis in maize kernels and may facilitate marker-based breeding for oil quantity and quality.
