摘要：

大豆荚皮的颜色是重要的驯化性状和表型特征,与炸荚习性和躲避捕食关系紧密。大豆荚皮颜色主要由2对等位基因控制,其中棕色荚皮L2基因尚未被鉴定。为了在大豆基因组上对该基因进行鉴定,为大豆棕色荚皮相关基因功能解析和育种应用提供一定的理论基础。以栽培大豆中龙优203(黄色荚皮)和野生大豆FF1235(黑色荚皮)为亲本构建F₂分离群体进行遗传分析。利用F₂群体棕色豆荚和黄色豆荚单株构建混池进行BSA-seq定位分析,并在此基础上进行重组交换单株分析。结果表明,大豆棕色荚皮性状为1对等位基因控制的质量性状。棕色荚皮L2基因关联区域位于3号染色体0~0.75 Mb的区段。进一步开发InDel分子标记进行精细定位,获得具有多态性的InDel引物7对。最终将棕色荚皮位点定位于3号染色体上的Indel-L2-3 ~Indel-L2-6,物理距离为344 kb。定位区间内共有候选基因32个,其中Glyma.03G005700基因注释为异丙基苹果酸聚合酶,与已发现的黑色荚皮基因L1(Glyma.19G120400)高度同源,其功能为将4-羟基丙酮酸转化为红果酸和番石榴酸,可能是调控大豆棕色荚皮形成的关键基因。

关键词: 大豆, 荚皮颜色, 基因定位, BSA-seq

Abstract:

Modern soybean cultivars typically display yellow to brown pods,while their wild ancestral specie,Glycine soja,possesses black pods.Pod color is an important domestication trait and phenotypic characteristic,which is strongly related to pod blasting habit and avoidance of predation.Two alleles were certified to control the pod color in soybean,among which the brown pod L2 gene has not been identified.In order to identify L2 gene on the soybean genome,and provide a theoretical basis for functional analysis and breeding application of brown pod related genes in soybean.The cultivated varieties Zhonglongyou 203(yellow pod)and wild varieties FF1235(black pod)were used as parents to generate an F₂ segregating population for genetic analysis in this study.The BSA-seq was performed using two gene pools which were constructed by brown pod and yellow pod individuals from the F₂ population,respectively.On this basis,recombinant exchange individuals were analysed.The results showed that brown pod was a quality trait controlled by a pair of alleles in soybean.The brown pod L2 gene was located in the 0—0.75 Mb region of Chromosome 3.By further use of 7 polymorphic InDel markers in fine mapping,the candidate interval was finally delimited between Indel-L2-3 and Indel-L2-6 with 344 kb physical distance.There were 32 candidate genes in the interval,among which Glyma.03G005700 gene was annotated as isopropylmalate polymerase.Glyma.03G005700 gene is highly homologous to the discovered black pod gene L1 (Glyma.19G120400),which may be responsible for converting 4-hydroxypyruvate into eucomic acid and piscidic acid,and may be a key gene in the regulating the formation of brown pod in soybean.

Key words: Soybean, Pod color, Mapping, BSA-seq