[目的]研究莴笋叶色变异的遗传基础，加速莴笋新品种育种进程，提高育种效率。[方法]通过构建红叶和绿叶莴笋杂交群体，分析遗传规律，利用混池分组分析法(BSA-seq)和图位克隆法精细定位并克隆了莴笋红叶基因Lactuca sativa Red Leaf 1(LsRL1)，根据变异位点设计了分子标记用于红叶莴笋分子标记辅助育种。[结果]遗传分析结果显示F2分离群体中红叶个体与绿叶个体的分离比为3∶1，说明研究中莴笋叶色表型受一个基因控制，且红叶相对于绿叶为显性性状。混池分组分析法(BSA-seq)将莴笋叶色基因LsRL1初步定位在莴笋第5染色体336。00 Mb到339。64 Mb的范围内。利用图位克隆的方法进一步将LsRL1基因的范围缩小至2个Indel分子标记ls06和ls12之间的85。17 kb区间内，这一区间内包含2个基因LOC111892298和LOC111892911。亲本间差异位点分析将LsRL1的候选基因确定为LOC111892911，该基因在拟南芥中的同源基因编码一个bHLH转录因子，参与花青素合成途径的调控。[结论]基于LsRL1基因在2个亲本间的插入缺失变异，我们开发了一个可用于红叶莴笋分子标记辅助育种的Indel标记，以加速红叶莴笋的育种进程。
Map-Based Cloning and Development of Molecular Markers of Red-Leaf Gene in Stem Lettuce(Lactuca sativa var.angustata)
[Objective]In order to study the genetic basis of leaf color of stem lettuce,accelerate the breeding process of red-leaf stem lettuce varieties and improve the breeding efficiency.[Method]In this study,a hybrid population of red-leaf and green-leaf stem lettuce was constructed,the genetic rule was analyzed,and the bulk segregant analysis(BSA-seq)and map-based cloning were used to finely map the red leaf gene Lactuca sativa Red Leaf 1(LsRL1),and a molecular marker was designed for marker-assisted breeding of red-leaf stem lettuce.[Result]Genetic analysis showed that the segrega-tion ratio of red-leaf individuals to green-leaf individuals in the F2 segregating population was 3∶1,indi-cating that the leaf color in this study was controlled by a single gene,and red leaf was a dominant trait relative to green leaf.The bulk segregant analysis(BSA-seq)method preliminarily mapped the leaf color gene LsRL1 to the range of 336.00 Mb to 339.64 Mb on chromosome 5 of stem lettuce.Using the map-based cloning method,the range of LsRL1 gene was further narrowed down to an 85.17 kb interval be-tween two Indel molecular markers ls06 and ls12,which contained two genes LOC111892298 and LOC111892911.Sequence difference analysis identified LOC111892911 as the candidate gene for LsRL1,which encodes a bHLH transcription factor in Arabidopsis thaliana and is involved in the regula-tion of anthocyanin synthesis pathway.[Conclusion]Based on the insertion/deletion variation of LsRL1 gene between two parents,we developed an Indel marker that can be used for molecular marker-assisted breeding of red-leaf stem lettuce to accelerate the breeding process.
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