利用 QTL-seq 快速鉴定影响油菜主效根长的 qPRL-C06 位点。
Rapid identification of a major locus qPRL-C06 affecting primary root length in Brassica napus by QTL-seq.
机构信息
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China.
Microelement Research Center, Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan 430070, China.
出版信息
Ann Bot. 2023 Apr 28;131(4):569-583. doi: 10.1093/aob/mcac123.
BACKGROUND AND AIMS
Brassica napus is one of the most important oilseed crops worldwide. Seed yield of B. napus significantly correlates with the primary root length (PRL). The aims of this study were to identify quantitative trait loci (QTLs) for PRL in B. napus.
METHODS
QTL-seq and conventional QTL mapping were jointly used to detect QTLs associated with PRL in a B. napus double haploid (DH) population derived from a cross between 'Tapidor' and 'Ningyou 7'. The identified major locus was confirmed and resolved by an association panel of B. napus and an advanced backcross population. RNA-seq analysis of two long-PRL lines (Tapidor and TN20) and two short-PRL lines (Ningyou 7 and TN77) was performed to identify differentially expressed genes in the primary root underlying the target QTLs.
KEY RESULTS
A total of 20 QTLs impacting PRL in B. napus grown at a low phosphorus (P) supply were found by QTL-seq. Eight out of ten QTLs affecting PRL at a low P supply discovered by conventional QTL mapping could be detected by QTL-seq. The locus qPRL-C06 identified by QTL-seq was repeatedly detected at both an optimal P supply and a low P supply by conventional QTL mapping. This major constitutive QTL was further confirmed by regional association mapping. qPRL-C06 was delimited to a 0.77 Mb genomic region on chromosome C06 using an advanced backcross population. A total of 36 candidate genes within qPRL-C06 were identified that showed variations in coding sequences and/or exhibited significant differences in mRNA abundances in primary root between the long-PRL and short-PRL lines, including five genes involved in phytohormone biosynthesis and signaling.
CONCLUSIONS
These results both demonstrate the power of the QTL-seq in rapid QTL detection for root traits and will contribute to marker-assisted selective breeding of B. napus cultivars with increased PRL.
背景和目的
油菜是世界上最重要的油料作物之一。油菜种子产量与主根长（PRL）显著相关。本研究的目的是鉴定油菜中与 PRL 相关的数量性状位点（QTL）。
方法
联合使用 QTL-seq 和常规 QTL 作图方法，在“Tapidor”和“Ningyou 7”杂交衍生的油菜双单倍体（DH）群体中鉴定与 PRL 相关的 QTL。通过油菜关联群体和先进回交群体，对鉴定出的主效位点进行验证和解析。对两个长 PRL 系（Tapidor 和 TN20）和两个短 PRL 系（Ningyou 7 和 TN77）进行 RNA-seq 分析，鉴定目标 QTL 下主根中差异表达的基因。
主要结果
通过 QTL-seq 共鉴定出油菜在低磷（P）供应条件下影响 PRL 的 20 个 QTL。常规 QTL 作图发现的影响 PRL 在低 P 供应下的 10 个 QTL 中的 8 个可以通过 QTL-seq 检测到。通过 QTL-seq 鉴定的 QTL qPRL-C06 在最优 P 供应和低 P 供应条件下均通过常规 QTL 作图重复检测到。该主效组成性 QTL 进一步通过区域关联作图得到证实。利用先进回交群体，将 qPRL-C06 限定在 C06 染色体上的 0.77 Mb 基因组区域内。在 qPRL-C06 内共鉴定出 36 个候选基因，这些基因在长 PRL 和短 PRL 系之间的主根中编码序列存在差异，或在 mRNA 丰度上存在显著差异，包括参与植物激素生物合成和信号转导的 5 个基因。
结论
这些结果均证明了 QTL-seq 在快速检测根性状 QTL 方面的强大功能，并将有助于油菜品种的标记辅助选择，以提高 PRL。
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