【作者】 杨文鹏； 郑用琏； 郑文婷； 冯睿；

【Author】 Yang Wen-Pengl, 2,*, Zheng Yong-Lianl,*, Zheng Wen-Tingl, Feng Ruil (~1 Nauonai Key Laboratory of Crop Genetic Improvement and National Center of Crop Molecular Breeding, Huazhong Agricultural University, Wuhan, Hubei 430070, P. R. China;~2Institute of Upland Food Crops, Guizhou Academy of Agricultural Sciences and Guizhou Center of Maize Engineering techniques, Guiyang, Guizhou 550006, P. R. China)

【机构】 作物遗传改良国家重点实验室和国家农作物分子技术育种中心华中农业大学；

【摘要】 玉米籽粒的赖氨酸含量是其营养品质的重要性状,其改良主要依靠高赖氨酸突变体的发现。从Robertson的Mutator突变体库的群体中,分离得到两个高赖氨酸突变系QCL3021和QCL3024,均带不透明胚乳。控制该突变的基因暂时被命名为opaque-16(o16)。为研究该基因的遗传位点及其效应,构建了两个F2:3群体,一个源自组合QCL3024×QCL3010(普通玉米系),另一个源自组合齐205(o2系)×QCL3021,用作遗传定位和基因聚合效应分析。两群体F3家系籽粒的赖氨酸含量分布及其正态性测验表明,籽粒赖氨酸含量特性分别受主效基因o16和o2、o16调控。基于这两个F2:3群体F2植株的标记基因型建立的连锁图及其F3家系的籽粒赖氨酸含量,用复合区间作图法将o16基因定位在第8染色体长臂上umc1121和umc1141之间离umc1141标记5cM以内,依群体的重组率不同而在3cM或2.2cM的位置。根据由o2系和o16系建立的F2:3群体的数据,分析了双隐性突变效应。由umc1066和umc1141标记鉴定的“o2o2o16o16”家系的平均赖氨酸含量分别比o2o2家系和“o16o16”家系的约高30%。与o2系亲本相比,在9个双隐性突变家系中,有7个家系的赖氨酸含量表现出不同的增量,平均增加约6%。o16突变的应用途径之一是将它与o2突变聚合,以期获得具有更高赖氨酸含量的突变。鉴定出的与o16基因紧密连锁的标记,将有助于通过分子标记辅助选择快速实现这一目的。更多还原

【Abstract】 The lysin content in maize endosperm protein is considered to be one of the most important traits for determining the nutritional quality of food and feed. Improving the protein quality of the maize kernel depends principally on finding a mutant with a higher lysine content. Two high-lysine mutant lines with opaque endosperm, QCL3024 and QCL3021, were isolated from a self-cross population derived from Robertson’s Mutator stocks. The gene controlling this mutation is temporarily termed opaque-16 （o16）. In order to illuminate the genetic locus and effect of the o16 gene, two F_2:3 populations, one developed from a cross between QCL3024 and QCL3010 （a wild type line） and another from a cross between Qi205 （opaque-2 line） and QCL3021, were created, and the F₃ seed were evaluated for lysine content. The distributions of lysine content in the two populations and tests for their normality indicate that the lysine content in the maize kernel is regulated by the major gene of o16 and genes of o2 and o16, respectively. Based on two data sets of the linkage maps of the F₂ plant marker genotype and the lysine content of F₃ seed originated from the two F_2:3 populations, the o16 gene was located within 5 cM, at either 3 cM or 2.2 cM from umc1141 in the interval between umc1121 and umc1141 on the long arm of chromosome 8, depending on the recombination rate in the different populations as determined by composite interval mapping. According to the data of the F_2:3 population constructed from the o2 and o16 line, the double recessive mutant effect was analyzed. The average lysine content of the "o2o2o16o16" families identified by the umc1066 and umc1141 markers was approximately 30% higher than that of the o2o2 and "o16o16" families. The lysine content of seven families among nine double recessive mutant families showed different increments, with an average increase of some 6% compared with that of the maternal o2 line. The potential application of the o16 mutant for maize high-lysine breeding may be to combine it with the o2 mutant bearing modifier genes, thus obtaining a mutant with much higher lysine content. For the purpose of pyramiding the o16 with o2 genes, the availability of closely linked markers of the o16 and o2 loci will facilitate marker-assisted selection and greatly reduce breeding time and effort.更多还原