一种水稻微效QTL精细定位和克隆新途径

水稻重要农艺性状一般由少数主效QTL和大量微效QTL共同控制。水稻主效QTL克隆已取得显著进展,而微效QTL由于遗传作用弱,表型鉴定易受测量误差影响,克隆进展缓慢,但微效QTL在水稻重要农艺性状调控中的作用不容忽视。本文介绍了一种水稻微效QTL精细定位和克隆的新途径。该途径包含2个阶段：1）应用剩余杂合体构建近等基因系群体进行目标QTL的精细定位;2）应用基因编辑技术创制候选基因突变体验证基因功能。应用该策略笔者所在团队在水稻第1染色体长臂精细定位了6个微效粒重和粒型QTL,并成功克隆首个微效粒重QTL。该技术可在方法上为水稻QTL克隆及新种质创制提供更多选择。

A New Approach for Fine-mapping and Map-based Cloning of Minor-Effect QTL in Rice

Important agronomic traits in rice are generally controlled by a few major-effect QTLs and a large number of minor-effect QTLs. Great progresses have been made in the cloning of major QTLs, while minor QTLs remain difficult to be cloned due to their small genetic effects and the influence of measurement error. A new approach for fine-mapping and map-based cloning of rice minor-effect QTL was introduced in this article. The approach includes two steps: 1) Use the residual heterozygote to construct near isogenic lines for fine-mapping of the target QTL; 2) Use the genome editing to create mutants of candidate genes for gene function identification. Using the strategy, we fine-mapped six minor QTLs for grain weight and grain size on the long arm of chromosome 1, and successfully cloned the first minor QTL for grain weight. We expect that this approach could provide more options for QTL cloning and new germplasm creation.