State Key Laboratory of Genetic Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200433, China; Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, Ministry of Education, Jiangxi Agricultural University, Nanchang 330045, China.
State Key Laboratory of Genetic Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200433, China.
Mol Plant. 2018 May 7;11(5):736-749. doi: 10.1016/j.molp.2018.03.005. Epub 2018 Mar 20.
Grain size and shape are important determinants of grain weight and yield in rice. Here, we report a new major quantitative trait locus (QTL), qTGW3, that controls grain size and weight in rice. This locus, qTGW3, encodes OsSK41 (also known as OsGSK5), a member of the GLYCOGEN SYNTHASE KINASE 3/SHAGGY-like family. Rice near-isogenic lines carrying the loss-of-function allele of OsSK41 have increased grain length and weight. We demonstrate that OsSK41 interacts with and phosphorylates AUXIN RESPONSE FACTOR 4 (OsARF4). Co-expression of OsSK41 with OsARF4 increases the accumulation of OsARF4 in rice protoplasts. Loss of function of OsARF4 results in larger rice grains. RNA-sequencing analysis suggests that OsARF4 and OsSK41 repress the expression of a common set of downstream genes, including some auxin-responsive genes, during rice grain development. The loss-of-function form of OsSK41 at qTGW3 represents a rare allele that has not been extensively utilized in rice breeding. Suppression of OsSK41 function by either targeted gene editing or QTL pyramiding enhances rice grain size and weight. Thus, our study reveals the important role of OsSK41 in rice grain development and provides new candidate genes for genetic improvement of grain yield in rice and perhaps in other cereal crops.
粒型和粒长是水稻粒重和产量的重要决定因素。在这里，我们报道了一个新的控制水稻粒型和粒重的主效数量性状位点（QTL），qTGW3。该位点编码 OsSK41（也称为 OsGSK5），属于 GLYCOGEN SYNTHASE KINASE 3/SHAGGY-like 家族。携带 OsSK41 功能缺失等位基因的水稻近等基因系的粒长和粒重增加。我们证明 OsSK41 与 AUXIN RESPONSE FACTOR 4（OsARF4）相互作用并磷酸化 OsARF4。在水稻原生质体中，共表达 OsSK41 和 OsARF4 会增加 OsARF4 的积累。OsARF4 的功能丧失导致水稻粒增大。RNA-seq 分析表明，在水稻籽粒发育过程中，OsARF4 和 OsSK41 共同抑制一组下游基因的表达，包括一些生长素响应基因。qTGW3 上的 OsSK41 功能丧失形式是一种在水稻育种中尚未广泛利用的稀有等位基因。通过靶向基因编辑或 QTL 叠加抑制 OsSK41 功能，可增强水稻粒长和粒重。因此，我们的研究揭示了 OsSK41 在水稻籽粒发育中的重要作用，并为水稻和其他谷物作物的产量遗传改良提供了新的候选基因。
