State Key Laboratory of Crop Stress Biology in Arid Areas and College of Agronomy, Northwest A&F University, Yangling, Shaanxi, 712100, China.
Institute of Crop Sciences, National Engineering Laboratory for Crop Molecular Breeding, Chinese Academy of Agricultural Sciences, National Center of Space Mutagenesis for Crop Improvement, Beijing, China.
BMC Plant Biol. 2023 Jun 22;23(1):333. doi: 10.1186/s12870-023-04343-3.
Plant height (PH) and spike compactness (SC) are important agronomic traits that affect yield improvement in wheat crops. The identification of the loci or genes responsible for these traits is thus of great importance for marker-assisted selection in wheat breeding.
In this study, we used a recombinant inbred line (RIL) population with 139 lines derived from a cross between the mutant Rht8-2 and the local wheat variety NongDa5181 (ND5181) to construct a high-density genetic linkage map by applying the Wheat 40 K Panel. We identified seven stable QTLs for PH (three) and SC (four) in two environments using the RIL population, and found that Rht8-B1 is the causal gene of qPH2B.1 by further genetic mapping, gene cloning and gene editing analyses. Our results also showed that two natural variants from GC to TT in the coding region of Rht8-B1 resulted in an amino acid change from G (ND5181) to V (Rht8-2) at the 175 position, reducing PH by 3.6%~6.2% in the RIL population. Moreover, gene editing analysis suggested that the height of T generation in Rht8-B1 edited plants was reduced by 5.6%, and that the impact of Rht8-B1 on PH was significantly lower than Rht8-D1. Additionally, analysis of the distribution of Rht8-B1 in various wheat resources suggested that the Rht8-B1b allele has not been widely utilized in modern wheat breeding.
The combination of Rht8-B1b with other favorable Rht genes might be an alternative approach for developing lodging-resistant crops. Our study provides important information for marker-assisted selection in wheat breeding.
株高（PH）和穗紧密度（SC）是影响小麦作物产量提高的重要农艺性状。因此，鉴定这些性状的基因或基因座对于小麦育种中的标记辅助选择非常重要。
本研究利用 Rht8-2 突变体与当地小麦品种 NongDa5181（ND5181）杂交衍生的 139 个重组自交系（RIL）群体，通过应用小麦 40K 面板构建了高密度遗传连锁图谱。我们在两个环境下使用 RIL 群体鉴定了 7 个与 PH（3 个）和 SC（4 个）相关的稳定 QTL，通过进一步的遗传作图、基因克隆和基因编辑分析，发现 qPH2B.1 的候选基因为 Rht8-B1。我们的研究结果还表明，Rht8-B1 编码区 GC 到 TT 的两个自然变异导致 175 位氨基酸由 ND5181 的 G 突变为 Rht8-2 的 V，使 RIL 群体的 PH 降低 3.6%~6.2%。此外，基因编辑分析表明，Rht8-B1 编辑植物 T 代的高度降低了 5.6%，Rht8-B1 对 PH 的影响明显低于 Rht8-D1。此外，对 Rht8-B1 在各种小麦资源中的分布分析表明，Rht8-B1b 等位基因在现代小麦育种中尚未得到广泛利用。
将 Rht8-B1b 与其他有利的 Rht 基因相结合可能是开发抗倒伏作物的一种替代方法。我们的研究为小麦育种中的标记辅助选择提供了重要信息。
