中国南瓜果皮颜色基因连锁的SNP分子标记的开发及应用

Development and Application of SNP Molecular Marker Linked to Pericarp Color in Cucurbita moschata Duch.

为了解中国南瓜(Cucurbita moschata Duch.)果皮颜色性状的遗传规律,筛选与皮色性状紧密连锁的SNP分子标记,本试验以中国南瓜墨绿无斑果皮自交系CMO-1(P1)和浅绿有斑果皮自交系CMO-97(P2)为试验材料构建F_2遗传群体,对果皮颜色pc(pericarp color)基因进行遗传分析和基因定位研究,将定位区间内的SNP分子标记转化为dCAPS分子标记进行开发及应用。结果表明,浅绿有斑果皮对墨绿无斑果皮表现为显性,由1个显性单基因控制。此外,利用前期构建的高密度遗传图谱,在8号连锁群上检测到了1个与中国南瓜果皮颜色性状和斑纹性状连锁的基因位点,2个性状可能由同1个基因控制。将此基因定位在具有最高表型解释概率的标记R1_47757附近,两侧翼标记为R2_47028和R2_63809,遗传距离为1.86 c M,物理距离为145.13 kb。生物信息学分析表明,该区段存在32个预测候选基因。同时,根据检测到的与皮色性状相关基因位点内的SNP分子标记信息,设计dCAPS分子标记引物,经过PCR扩增及酶切验证,开发出2个扩增效率高、稳定性好的dCAPS分子标记,根据酶切带型可以准确的将F_2群体中的墨绿无斑表型和浅绿有斑表型区分开,且可以用于鉴定中国南瓜自交系材料的果皮颜色。本研究结果为南瓜果皮颜色的形成机理及开展南瓜分子标记辅助育种奠定了一定的理论基础。

In order to understand the inheritance of pericarp color and develop SNP molecular markers that colosely linked to the pericarp color trait of pumpkin（ Cucurbita moschata Duch.）,genetic analysis and gene mapping were carried out on green pericarp color fruit using CMO-1（ dark green without stripe） and CMO-97（ light green with stripe） as experimental materials in this study. Meanwhile,dCAPS molecular markers that generated by SNP molecular markers have been developed and applied in the mapped interval. Results indicated that light green with stripe was dominate to dark green with no stripe,the pericarp color was controlled by single genes,designated as pc. Based on high-density genetic map constructed previously,a locus related to pericarp color and pericarp stripe traits of pumpkin was detected in linkage group 8,and both traits might be controlled by the same gene. The pc gene was mapped near R1_47757 which had the highest phenotypic variance explained（ PVE）. The flanking markers R2_47028 and R2_63809 were linked to the pc gene with a genetic distance of 1. 86 cM,and a physical distance of 145. 13 kb. Bioinformatics analysis revealed that there were 32 prediction candidate genes in this region. At the same time,dCAPS primers were designed based on the information of SNP molecular markers related to pericarp color trait. After PCR amplification and restriction enzyme digestion,two dCAPS molecular markers with high amplification efficiency and stability were selected to distinguish dark green without stripe phenotype from light green with stripe in F2 population according to the digestion patterns,and used to identify the pericarp color of pumpkin inbred lines. These results laid the foundation for the molecular mechanism of pericarp color development and molecular marker-assisted breeding of Cucurbita moschata Duch.