In rice grains, the Waxy (Wx) gene is responsible for the synthesis of amylose, the most important determinant for eating and cooking quality. The effects of several Wx alleles on amylose content and the taste of cooked rice have been elucidated. However, the relationship between artificial selection and the evolution of various Wx alleles as well as their distribution remain unclear. Here we report the identification of an ancestral allele, Wx^lv, which dramatically affects the mouthfeel of rice grains by modulating the size of amylose molecules. We demonstrated that Wx^lv originated directly from wild rice, and the three major Wx alleles in cultivated rice (Wx^b, Wx^a, and Wxⁱⁿ) differentiated after the substitution of one base pair at the functional sites. These data indicate that the Wx^lv allele played an important role in artificial selection and domestication. The findings also shed light on the evolution of various Wx alleles, which have greatly contributed to improving the eating and cooking quality of rice.

在稻谷中，Waxy（Wx）基因负责直链淀粉的合成，直链淀粉是决定饮食质量和烹饪质量的最重要因素。阐明了几个Wx等位基因对直链淀粉含量和米饭味道的影响。但是，人工选择与各种Wx等位基因的进化及其分布之间的关系仍然不清楚。在这里，我们报告了祖先等位基因Wx ^lv的鉴定，该基因通过调节直链淀粉分子的大小显着影响稻米的口感。我们证明了Wx ^lv直接来自野生稻，而三大Wx在功能位点替换一个碱基对后，栽培稻中的等位基因（Wx ^b，Wx ^a和Wx ⁱⁿ）分化。这些数据表明Wx ^lv等位基因在人工选择和驯化中起重要作用。这些发现还揭示了各种Wx等位基因的进化，这些等位基因极大地促进了水稻的食用和烹饪质量。