Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, 305-8686, Tsukuba, Ibaraki, Japan.
Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences, 210014, Nanjing, P.R. China.
BMC Genomics. 2021 Feb 23;22(1):132. doi: 10.1186/s12864-021-07445-0.
The root system provides nutrient absorption and is closely related to abiotic stress tolerance, but it is difficult to study the roots under field conditions. This study was conducted to identify quantitative trait loci (QTL) associated with primary root length (PRL) during soybean seedling growth in hydroponic conditions. A total of 103 F recombinant inbred lines (RILs) derived from a cross between K099 (short primary root) and Fendou 16 (long primary root) were used to identify QTL for PRL in soybean. The RIL population was genotyped with 223 simple sequence repeats markers covering 20 chromosomes. Phenotyping for primary root length was performed for 3-weeks plants grown in hydoponic conditions. The identified QTL was validated in near isogenic lines and in a separate RIL population.
QTL analysis using inclusive composite interval mapping method identified a major QTL on Gm16 between SSR markers Sat_165 and Satt621, explaining 30.25 % of the total phenotypic variation. The identified QTL, qRL16.1, was further confirmed in a segregating population derived from a residual heterozygous line (RHLs-98). To validate qRL16.1 in a different genetic background, QTL analysis was performed in another F RIL population derived from a cross between Union (medium primary root) and Fendou 16, in which a major QTL was detected again in the same genomic region as qRL16.1, explaining 14 % of the total phenotypic variation for PRL. In addition, the effect of qRL16.1 was confirmed using two pair of near-isogenic lines (NILs). PRL was significantly higher in NILs possessing the qRL16.1 allele from Fendou 16 compared to allele from K099.
The qRL16.1 is a novel QTL for primary root length in soybean which provides important information on the genetic control of root development. Identification of this major QTL will facilitate positional cloning and DNA marker-assisted selection for root traits in soybean.
根系提供养分吸收，与非生物胁迫耐受密切相关，但在田间条件下研究根系较为困难。本研究旨在鉴定在水培条件下大豆幼苗生长过程中与主根长度（PRL）相关的数量性状位点（QTL）。利用 K099（主根短）和 Fendou 16（主根长）杂交产生的 103 个重组自交系（RIL）群体，鉴定大豆 PRL 的 QTL。该 RIL 群体使用 223 个简单序列重复标记进行基因型分析，这些标记覆盖 20 条染色体。在水培条件下对生长 3 周的植株进行主根长度表型分析。在近等基因系和另一个 RIL 群体中验证鉴定的 QTL。
使用包含复合区间作图法的 QTL 分析方法，在 Gm16 上 SSR 标记 Sat_165 和 Satt621 之间鉴定到一个主效 QTL，解释了 30.25%的总表型变异。鉴定到的 QTL，qRL16.1，在一个由剩余杂合系（RHLs-98）衍生的分离群体中进一步得到验证。为了在不同的遗传背景下验证 qRL16.1，在另一个由 Union（主根中等长度）和 Fendou 16 杂交产生的 F RIL 群体中进行 QTL 分析，在同一基因组区域再次检测到一个主效 QTL，解释了 PRL 总表型变异的 14%。此外，使用两对近等基因系（NILs）验证了 qRL16.1 的效应。与来自 K099 的等位基因相比，来自 Fendou 16 的 qRL16.1 等位基因在 NILs 中显著提高了 PRL。
qRL16.1 是大豆主根长度的一个新 QTL，为根系发育的遗传控制提供了重要信息。该主效 QTL 的鉴定将有助于大豆根性状的定位克隆和 DNA 标记辅助选择。
