National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan 430070, China.
J Integr Plant Biol. 2021 May;63(5):878-888. doi: 10.1111/jipb.13011. Epub 2021 Mar 26.
Appearance and taste are important factors in rice (Oryza sativa) grain quality. Here, we investigated the taste scores and related eating-quality traits of 533 diverse cultivars to assess the relationships between-and genetic basis of-rice taste and eating-quality. A genome-wide association study highlighted the Wx gene as the major factor underlying variation in taste and eating quality. Notably, a novel waxy (Wx) allele, Wx , which combined two mutations from Wx and Wx , exhibited a unique phenotype. Reduced GBSSI activity conferred Wx rice with both a transparent appearance and good eating quality. Haplotype analysis revealed that Wx was derived from intragenic recombination. In fact, the recombination rate at the Wx locus was estimated to be 3.34 kb/cM, which was about 75-fold higher than the genome-wide mean, indicating that intragenic recombination is a major force driving diversity at the Wx locus. Based on our results, we propose a new network for Wx evolution, noting that new Wx alleles could easily be generated by crossing genotypes with different Wx alleles. This study thus provides insights into the evolution of the Wx locus and facilitates molecular breeding for quality in rice.
外观和口感是稻米（Oryza sativa）品质的重要因素。在这里，我们研究了 533 个不同品种的口感评分和相关的食用品质特性，以评估稻米口感和食用品质之间的关系及其遗传基础。全基因组关联研究突出了 Wx 基因是导致口感和食用品质差异的主要因素。值得注意的是，一种新型的蜡质（Wx）等位基因 Wx ，它结合了 Wx 和 Wx 两个突变，表现出独特的表型。GBSSI 活性的降低赋予了 Wx 稻米透明的外观和良好的食用品质。单倍型分析表明 Wx 是由基因内重组产生的。事实上，Wx 基因座的重组率估计为 3.34 kb/cM，大约是全基因组平均水平的 75 倍，表明基因内重组是驱动 Wx 基因座多样性的主要力量。基于我们的研究结果，我们提出了一个 Wx 进化的新网络，指出通过杂交具有不同 Wx 等位基因的基因型很容易产生新的 Wx 等位基因。因此，本研究为 Wx 基因座的进化提供了新的见解，并促进了稻米品质的分子育种。
