Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China.
Guangdong Provincial Key Lab of Biotechnology for Plant Development, South China Normal University, Guangzhou 510631, China.
Int J Mol Sci. 2022 Oct 18;23(20):12478. doi: 10.3390/ijms232012478.
Pyramiding of quantitative trait loci (QTLs) is a powerful approach in breeding super-high-yield varieties. However, the performance of QTLs in improving rice yield varies with specific genetic backgrounds. In a previous study, we employed the CRISPR/Cas9 system to target three yield-related genes, , , and in japonica 'Zhonghua 11', mutants of which featured large panicle, big grain, few sterile tillers, and thicker culm, respectively. In this paper, four pyramided lines, including , , , and , were further generated by conventional cross-breeding to be tested. Agronomic traits analysis showed that: (1) the stacking lines carried large panicles with an increased spikelet number in the main panicle or panicle; (2) the grain weight of the stacking lines, especially and were heavier than those in single mutants; (3) both and produced more grain yield per plant than single mutant lines; (4) pyramided lines were higher than single mutants and transcriptome analysis found improved expression levels of genes related to lipid, amino acid, and carbohydrate transport and metabolism in lines pyramiding three mutant alleles, possibly as a result of complementary and additive effects. Accordingly, the alteration of gene-expression patterns relating to hormone signaling, plant growth, and seed size control was characterized in pyramided lines. The present study not only investigates the effects of pyramiding genes, but also may provide an efficient strategy for breeding super-high-yield rice by reducing the time cost of developing pyramided lines.
聚合数量性状位点（QTLs）是培育超高产品种的一种强大方法。然而，QTLs 在提高水稻产量方面的表现因特定的遗传背景而异。在之前的研究中，我们使用 CRISPR/Cas9 系统靶向三个与产量相关的基因、、和在粳稻‘中华 11’中，其突变体分别具有大穗、大粒、少不育分蘖和更粗的茎。在本文中，我们通过常规杂交进一步生成了四个聚合系，包括、、和，以进行测试。农艺性状分析表明：（1）聚合系携带大穗，主穗或穗上的小穗数增加；（2）聚合系的粒重，特别是和，比单突变体更重；（3）和都比单突变体系产生更高的每株产量；（4）聚合系比单突变体更高，转录组分析发现，在聚合三个突变等位基因的系中，与脂质、氨基酸和碳水化合物运输和代谢相关的基因表达水平提高，可能是由于互补和累加效应。因此，在聚合系中，与激素信号、植物生长和种子大小控制相关的基因表达模式发生了改变。本研究不仅考察了基因聚合的效果，还可能为通过减少聚合系的开发时间成本来培育超高产水稻提供一种有效的策略。
