Ferreira Rebecca Caroline Ulbricht, Lara Letícia Aparecida de Castro, Chiari Lucimara, Barrios Sanzio Carvalho Lima, do Valle Cacilda Borges, Valério José Raul, Torres Fabrícia Zimermann Vilela, Garcia Antonio Augusto Franco, de Souza Anete Pereira
Center for Molecular Biology and Genetic Engineering, University of Campinas, Campinas, Brazil.
Genetics Department, Escola Superior de Agricultura "Luiz de Queiroz", University of São Paulo, Piracicaba, Brazil.
Front Plant Sci. 2019 Feb 21;10:92. doi: 10.3389/fpls.2019.00092. eCollection 2019.
(Stapf) R. D. Webster is one of the most important African forage grasses in Brazilian beef production. Currently available genetic-genomic resources for this species are restricted mainly due to polyploidy and apomixis. Therefore, crucial genomic-molecular studies such as the construction of genetic maps and the mapping of quantitative trait loci (QTLs) are very challenging and consequently affect the advancement of molecular breeding. The objectives of this work were to (i) construct an integrated genetic map for a full-sibling progeny using GBS-based markers with allele dosage information, (ii) detect QTLs for spittlebug () resistance, and (iii) seek putative candidate genes involved in defense against biotic stresses. We used the genome a reference to align GBS reads and selected 4,240 high-quality SNP markers with allele dosage information. Of these markers, 1,000 were distributed throughout nine homologous groups with a cumulative map length of 1,335.09 cM and an average marker density of 1.33 cM. We detected QTLs for resistance to spittlebug, an important pasture insect pest, that explained between 4.66 and 6.24% of the phenotypic variation. These QTLs are in regions containing putative candidate genes related to defense against biotic stresses. Because this is the first genetic map with SNP autotetraploid dosage data and QTL detection in , it will be useful for future evolutionary studies, genome assembly, and other QTL analyses in spp. Moreover, the results might facilitate the isolation of spittlebug-related candidate genes and help clarify the mechanism of spittlebug resistance. These approaches will improve selection efficiency and accuracy in molecular breeding and shorten the breeding cycle.
（斯塔夫）R. D. 韦伯斯特草是巴西牛肉生产中最重要的非洲饲草之一。目前该物种可用的遗传基因组资源主要受多倍体和无融合生殖的限制。因此，诸如构建遗传图谱和定位数量性状位点（QTL）等关键的基因组分子研究极具挑战性，从而影响了分子育种的进展。本研究的目的是：（i）使用具有等位基因剂量信息的基于简化基因组测序（GBS）的标记构建全同胞后代的整合遗传图谱；（ii）检测对沫蝉（ ）抗性的QTL；（iii）寻找参与抵御生物胁迫的推定候选基因。我们以 基因组为参考来比对GBS读数，并选择了4240个具有等位基因剂量信息的高质量单核苷酸多态性（SNP）标记。在这些标记中，1000个分布在9个同源组中，累积图谱长度为1335.09厘摩（cM），平均标记密度为1.33 cM。我们检测到了对重要牧场害虫沫蝉抗性的QTL，其解释了4.66%至6.24%的表型变异。这些QTL位于包含与抵御生物胁迫相关的推定候选基因的区域。由于这是第一张具有SNP同源四倍体剂量数据和在 中进行QTL检测的遗传图谱，它将有助于未来 属物种的进化研究、基因组组装和其他QTL分析。此外，研究结果可能有助于分离与沫蝉相关的候选基因，并有助于阐明沫蝉抗性的机制。这些方法将提高 分子育种的选择效率和准确性，并缩短育种周期。
