摘要：

对黄瓜种质资源果柄长度性状进行评价,挖掘相关变异位点,有助于提高黄瓜品质育种效率。首先对229份黄瓜种质资源开花当天和商品瓜时期果柄长度性状进行评价,再以鉴定出的中长果柄自交系9D6和6457与短果柄自交系MT和6429为亲本分别构建F₂群体,采用QTL-seq对黄瓜果柄长度性状调控基因进行QTL定位,并通过qRT-PCR对候选基因进行表达模式分析和变异位点验证。结果表明,不同种质资源开花当天和商品瓜时期果柄长度呈极显著正相关,开花当天和商品瓜时期果柄长度变异分别为0.4~6.2 cm,0.4~5.3 cm。遗传分析表明,黄瓜果柄长度性状广义遗传力分别为69.4%,94.4%,具有典型的数量性状遗传特征。两套F₂群体中分别检测到开花当天果柄长度相关的QTL位点6,5个,其中5号染色体0.840~7.350 Mb和6号染色体17.735~31.087 Mb的2个QTL区间在两套群体中共定位。在共定位QTL区间内预测到CsPG1 (CsaV3_5G010970)和CsROS1 (CsaV3_6G040410)。中长果柄亲本9D6和6457 CsPG1编码区保守结构域均存在非同义SNP311 C/T;另外,9D6的CsPG1启动子存在9 bp碱基插入,其中包含TATA-box,可能与其开花当天表达量显著高于其他亲本有关。短果柄亲本6429的CsROS1编码区存在3 bp碱基缺失,导致编码蛋白质缺失1个丝氨酸残基。中长果柄亲本9D6和6457的CsROS1编码区存在同义突变SNP3282 T/C,导致偏好密码子UAU变为非偏好密码子UAC。表明CsPG1和CsROS1是黄瓜果柄长的关键候选基因。

关键词: 黄瓜, 种质资源, 果柄长度, 遗传分析, QTL分析, qRT-PCR

Abstract:

Evaluating the pedicel length trait of cucumber germplasm resources and exploring the related variation sites can help improve the breeding efficiency of cucumber quality.This study first evaluates the fruit pedicle length traits of 229 cucumber germplasm resources on the day of flowering and during the commercial fruiting period.Then,using the identified medium to long pedicle self-cross lines 9D6 and 6457 as parents,and short pedicle self-cross lines MT and 6429 as parents,F₂ populations were constructed.QTL-seq was used to locate the QTLs controlling cucumber pedicel length traits,and Real-time Quantitative PCR(qRT-PCR)was employed to analyze the expression patterns of candidate genes and validate variant sites.The results showed that the pedicel length on the day of flowering and during the commercial melon period was positively correlated with the germplasm resources,and the variation of the pedicel length on the day of flowering and during the commercial melon period was 0.4—6.2 cm,0.4—5.3 cm,respectively.Genetic analysis showed that the broad genetic forces of cucumber pedicel length were 69.4%,94.4%,respectively,showing typical quantitative trait inheritance characteristics.Six and five QTL loci related to pedicel length on the day of flowering were detected in two sets of F₂ population,respectively.Two QTL intervals 0.840—7.350 Mb on chromosome 5 and 17.735—31.087 Mb on chromosome 6 were co-localized in the two sets of populations.CsPG1(CsaV3_5G010970)and CsROS1 (CsaV3_6G040410)were predicted within the QTL interval of co-location.A non-synonymous SNP311 C/T was found at the conserved domain of CsPG1 coding sequence(CDS)in the medium-long fruit pedicel parental lines 9D6 and 6457.In addition,there was a 9-bp base insertion in the CsPG1 promoter of 9D6,which contained TATA-box,which may be related to its significantly higher expression than other parents on the day of flowering.A 3-bp deletion was found at the CDS of CsROS1 in the short fruit pedicel parental lines 6429,resulting in the loss of one serine residue in the encoded protein.A synonymous SNP3282 T/C was detected at the CDS in the long fruit pedicel parental lines 9D6 and 6457,causing the preferred codon UAU to change to the non-preferred codon UAC.CsPG1 and CsROS1 were considered to be key candidate genes for cucumber fruit pedicel length.

Key words: Cucumber, Germplasm resource, Pedicel length, Genetic analysis, QTL analysis, qRT-PCR

中图分类号: 

• S642.2

• S32作物品种与种质资源(品种资源)