Plant Genomics Laboratory, Department of Plant Biotechnology, College of Life Sciences, Sejong University, 209 Neungdong-ro, Gwanjing-gu, Seoul, 143-747, Republic of Korea.
Institute of Mathematics and Statistics, Federal University of Goiás, Goiânia, Brazil.
Theor Appl Genet. 2019 May;132(5):1505-1521. doi: 10.1007/s00122-019-03295-3. Epub 2019 Feb 1.
QTL-seq analysis identified three major QTLs conferring subgynoecy in cucumbers. Furthermore, sequence and expression analyses predicted candidate genes controlling subgynoecy. The cucumber (Cucumis sativus L.) is a typical monoecious having individual male and female flowers, and sex differentiation is an important developmental process that directly affects its fruit yield. Subgynoecy represents a sex form with a high degree of femaleness and would have alternative use as gynoecy under limited resource conditions. Recently, many studies have been reported that QTL-seq, which integrates the advantages of bulked segregant analysis and high-throughput whole-genome resequencing, can be a rapid and cost-effective way of mapping QTLs. Segregation analysis in the F and BC populations derived from a cross between subgynoecious LOSUAS and monoecious BMB suggested the quantitative nature of subgynoecy in cucumbers. Both genome-wide SNP profiling of subgynoecious and monoecious bulks constructed from F and BC plants consistently identified three significant genomic regions, one on chromosome 3 (sg3.1) and another two on short and long arms of chromosome 1 (sg1.1 and sg1.2). Classical QTL analysis using the F confirmed sg3.1 (R = 42%), sg1.1 (R = 29%) and sg1.2 (R = 18%) as major QTLs. These results revealed the unique genetic inheritance of subgynoecious line LOSUAS through two distinct major QTLs, sg3.1 and sg1.1, which mainly increase degree of femaleness, while another QTL, sg1.2, contributes to decrease it. This study demonstrated that QTL-seq allows rapid and powerful detection of QTLs using preliminary generation mapping populations such as F or BC population and further that the identified QTLs could be useful for molecular breeding of cucumber lines with high yield potential.
QTL-seq 分析鉴定了三个控制黄瓜亚雌蕊的主要 QTL。此外，序列和表达分析预测了控制亚雌蕊的候选基因。黄瓜（Cucumis sativus L.）是一种典型的雌雄同体植物，具有个体雄性和雌性花，性别分化是一个重要的发育过程，直接影响其果实产量。亚雌蕊代表了一种高度雌性化的性别形式，在资源有限的情况下，它可以作为雌蕊替代使用。最近，许多研究报道称，QTL-seq 整合了 bulked segregant analysis 和高通量全基因组重测序的优势，可以快速有效地定位 QTL。在亚雌蕊 LOSUAS 和雌雄同体 BMB 杂交产生的 F 和 BC 群体中进行的分离分析表明，黄瓜的亚雌蕊具有数量遗传性质。来自 F 和 BC 植物构建的亚雌蕊和雌雄同体群体的全基因组 SNP 分析一致鉴定出三个显著的基因组区域，一个位于第 3 号染色体上（sg3.1），另两个位于第 1 号染色体的短臂和长臂上（sg1.1 和 sg1.2）。利用 F 代进行的经典 QTL 分析证实 sg3.1（R=42%）、sg1.1（R=29%）和 sg1.2（R=18%）为主要 QTL。这些结果表明，通过两个不同的主要 QTL sg3.1 和 sg1.1，亚雌蕊系 LOSUAS 的独特遗传继承主要增加了雌性程度，而另一个 QTL sg1.2 则有助于降低雌性程度。本研究表明，QTL-seq 允许使用初步的遗传作图群体（如 F 或 BC 群体）快速而有力地检测 QTL，进一步表明所鉴定的 QTL 可用于黄瓜高产量潜力品系的分子育种。
