College of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin 150030, China.
Key Laboratory of Biology and Genetic Improvement of Horticulture Crops (Northeast Region), Ministry of Agriculture and Rural Affairs, Harbin 150030, China.
Int J Mol Sci. 2023 Oct 30;24(21):15755. doi: 10.3390/ijms242115755.
The genetic regulatory basis of qualitative and quantitative phenotypes of watermelon is being investigated in different types of molecular and genetic breeding studies around the world. In this study, biparental F mapping populations were developed over two experimental years, and the collected datasets of fruit and seed traits exhibited highly significant correlations. Whole-genome resequencing of comparative parental lines was performed and detected single nucleotide polymorphism (SNP) loci were converted into cleaved amplified polymorphic sequence (CAPS) markers. The screened polymorphic markers were genotyped in segregating populations and two genetic linkage maps were constructed, which covered a total of 2834.28 and 2721.45 centimorgan (cM) genetic lengths, respectively. A total of 22 quantitative trait loci (QTLs) for seven phenotypic traits were mapped; among them, five stable and major-effect QTLs (PC-8-1, SL-9-1, SWi-9-1, SSi-9-1, and SW-6-1) and four minor-effect QTLs (PC-2-1 and PC-2-2; PT-2-1 and PT-2-2; SL-6-1 and SSi-6-2; and SWi-6-1 and SWi-6-2) were observed with 3.77-38.98% PVE. The adjacent QTL markers showed a good fit marker-trait association, and a significant allele-specific contribution was also noticed for genetic inheritance of traits. Further, a total of four candidate genes (, , , and ) were spotted in the stable colocalized QTLs of seed size linked traits (SL-9-1 and SWi-9-1) that showed non-synonymous type mutations. The gene expression trends indicated that the seed morphology had been formed in the early developmental stage and showed the genetic regulation of seed shape formation. Hence, we think that our identified QTLs and genes would provide powerful genetic insights for marker-assisted breeding aimed at improving the quality traits of watermelon.
正在世界各地进行不同类型的分子和遗传育种研究，以研究西瓜的定性和定量表型的遗传调控基础。在这项研究中，在两个实验年度内开发了双亲和 F 映射群体，并且收集的果实和种子性状数据集表现出高度显著的相关性。对比较亲本系进行了全基因组重测序，并检测到单核苷酸多态性（SNP）位点转化为切割扩增多态性序列（CAPS）标记。筛选出的多态性标记在分离群体中进行了基因分型，并构建了两个遗传连锁图谱，分别覆盖了 2834.28 和 2721.45 厘摩（cM）的遗传长度。共定位到 7 个表型性状的 22 个数量性状位点（QTL）；其中，观察到 5 个稳定且主效 QTL（PC-8-1、SL-9-1、SWi-9-1、SSi-9-1 和 SW-6-1）和 4 个微效 QTL（PC-2-1 和 PC-2-2；PT-2-1 和 PT-2-2；SL-6-1 和 SSi-6-2；以及 SWi-6-1 和 SWi-6-2），贡献率为 3.77-38.98%。相邻 QTL 标记与性状关联良好，并且还观察到遗传性状的等位基因特异性贡献。此外，在种子大小连锁性状（SL-9-1 和 SWi-9-1）的稳定共定位 QTL 中，发现了总共 4 个候选基因（、、、和），它们具有非同义类型的突变。基因表达趋势表明，种子形态已经在早期发育阶段形成，并显示出种子形状形成的遗传调控。因此，我们认为我们鉴定的 QTL 和基因将为旨在改善西瓜品质性状的标记辅助育种提供有力的遗传见解。
