黄瓜叶面积主效QTL小叶2基因(ll2)的遗传定位  

Genetic Mapping of Little Leaf 2(ll2), a Major QTL Controlling Leaf Area in Cucumber(Cucumis sativus L.)

作　　者：史婷婷[1,2] 王深浩[2] 林涛[2] 杨清[1] 黄三文[1,2] 

机构地区：[1]南京农业大学生命科学学院,南京210095 [2]中国农业科学院蔬菜花卉研究所,农业部园艺作物遗传改良重点实验室,中荷联合园艺作物基因组技术实验室,北京100081

出　　处：《农业生物技术学报》2014年第4期415-421,共7页Journal of Agricultural Biotechnology

基　　金：国家重大基础研究(973)项目(No.2012CB113900);国家自然科学基金(No.31225025;No.30972011和No.31272161)

摘　　要：叶片面积影响光合作用效率，是农作物产量的重要构成性状之一。野生黄瓜（Cucumis sativus var. hardwickii）的叶片较小，经过人工驯化后的栽培黄瓜（Cucumis sativus var. sativus）的叶片面积扩大了2~3倍。前人研究已经将控制黄瓜叶面积的主效基因之一ll （little leaf） 定位在第6号染色体上。本研究以黄瓜小叶品系XF-24（P1）、大叶品系DF-32（P2）杂交产生的205个单株的F2群体为研究材料，用SAS软件对成熟期调查的各单株相同节位的叶面积进行正态性检验，结果服从正态分布，符合数量性状的遗传特征。为了有效地加快研究进程，在双亲测序情况下，采用插入缺失位点（insertion and deletion,InDel）标记进行基因定位。研究结合双亲全基因组测序数据，生物信息学分析得出双亲序列之间的InDel位点，用Primer Premier 5.0软件在所有染色体上均匀设计88对InDel标记引物，扩增采用分离群体分组混合分析法（bulked segregant analysis, BSA）组建大叶、小叶基因池，池间有多态的引物再进一步扩增F2群体DNA，筛选到7个与黄瓜叶面积基因ll2连锁的分子标记，位于黄瓜第7号染色体上，分别是InDel-1、InDel-2、InDel-3、InDel-4、InDel-5、InDel-6、InDel-7。建立遗传连锁图谱并进行区间作图寻找QTL位点，结果显示，遗传连锁图谱包含以上7个InDel标记，连锁区间为22.1 cM，包括1个控制黄瓜叶片大小的主效QTL位点ll2 （little leaf 2），位于标记InDel-2与InDel-4之间，这两个标记之间物理距离为1.24 Mb。与前人的研究结果相比，定位区间更小且是7号染色体上首次发现的黄瓜叶面积QTL位点。截止目前，在黄瓜6号、7号染色体共发现了2个黄瓜叶面积主效QTL位点，分别是ll和ll2，表明黄瓜叶面积遗传机制复杂。叶面积主效QTL ll2的遗传定位，对于控制黄瓜叶片面积的遗传机制和分子机理研究以及分子标记�Leaf area is critical to photosynthesis efficiency and a major trait affecting crop yield. Wild cucumbers （Cucumis sativus var. hardwickii） bearing little leaves, after domestication, the leaf area of cultivated cucumber （Cucumis. sativus var. sativus） is enlarged around 2 to 3 times. Previously, a major gene ll （little leaf） was mapped on chromosome 6. In this study, F2 population of 205 individuals segregating at leaf area by crossing from 2 cucumber lines XF-24 （little leaf） and DF-32 （large leaf）. The result of normal distribution test by SAS showed that the area data of mature leaves from the same nodes of 205 individuals were in normal distribution, which characterized the trait of quantitative inheritance. In order to effectively accelerate the process of study, we utilized insertion and deletion（InDel） markers for gene mapping after the whole genome sequencing of parents of F2 population. InDels of the whole genome sequencing data from parents of F2 population were found in bioinformatics analysis. Eighty and eight InDel markers were evenly designed on all chromosomes by Primer Premier 5.0. These InDels were acted as primers to amplify the two gene pools of both large and little leaves, which came from bulked segregant analysis, the polymorphic InDels screened from the previous step were used to amplify DNA of F2 population, and 7 InDel markers identified on chromosome 7 were InDel-1, InDel-2, InDel-3, InDel-4, InDel-5, InDel-6 and InDel-7, respectively. Genetic linkage map was constructed by JionMap4 .0 and QTL locus was found by MapQTL4.0, using the result of PCR and traits of F2 population. Seven InDel markers listed above were contained in the genetic linkage map, spanning 22.1 cM. This result led to the discovery of a second major QTL （gene） controlling leaf area in cucumber, here designated ll2 （little leaf 2）. Further analysis delimited ll2 into a 1.24 Mb genomic interval between the 2 markers of InDel-2 and InDel-4. ll2 was the first QTL found on chromosome 7 with a

关 键 词：黄瓜 叶面积 LITTLE leaf2(ll2) QTL定位 

分 类 号：S511.21[农业科学—作物学]