Department of Plant Science, Plant Genomics and Breeding Institute, and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea.
Mol Plant. 2013 Nov;6(6):1877-88. doi: 10.1093/mp/sst088. Epub 2013 May 27.
Heading date and photoperiod sensitivity are fundamental traits that determine rice adaptation to a wide range of geographic environments. By quantitative trait locus (QTL) mapping and candidate gene analysis using whole-genome re-sequencing, we found that Oryza sativa Pseudo-Response Regulator37 (OsPRR37; hereafter PRR37) is responsible for the Early heading7-2 (EH7-2)/Heading date2 (Hd2) QTL which was identified from a cross of late-heading rice 'Milyang23 (M23)' and early-heading rice 'H143'. H143 contains a missense mutation of an invariantly conserved amino acid in the CCT (CONSTANS, CO-like, and TOC1) domain of PRR37 protein. In the world rice collection, different types of nonfunctional PRR37 alleles were found in many European and Asian rice cultivars. Notably, the japonica varieties harboring nonfunctional alleles of both Ghd7/Hd4 and PRR37/Hd2 flower extremely early under natural long-day conditions, and are adapted to the northernmost regions of rice cultivation, up to 53° N latitude. Genetic analysis revealed that the effects of PRR37 and Ghd7 alleles on heading date are additive, and PRR37 down-regulates Hd3a expression to suppress flowering under long-day conditions. Our results demonstrate that natural variations in PRR37/Hd2 and Ghd7/Hd4 have contributed to the expansion of rice cultivation to temperate and cooler regions.
水稻的生育期和光周期敏感性是决定其适应广泛地理环境的基本特征。通过全基因组重测序的数量性状位点（QTL）作图和候选基因分析，我们发现水稻拟南芥应答调节因子 37（OsPRR37；以下简称 PRR37）是导致早穗 7-2（EH7-2）/穗期 2（Hd2）QTL 的原因，该 QTL 是由晚穗水稻‘Milyang23（M23）’和早穗水稻‘H143’杂交产生的。H143 在 PRR37 蛋白的 CCT（CONSTANS、CO-like 和 TOC1）结构域中含有一个保守氨基酸的错义突变。在世界水稻资源中，许多欧洲和亚洲水稻品种中发现了不同类型的无功能 PRR37 等位基因。值得注意的是，含有 Ghd7/Hd4 和 PRR37/Hd2 两个无功能等位基因的粳稻品种在自然长日照条件下开花极早，适应了水稻种植的最北部地区，最高可达北纬 53°。遗传分析表明，PRR37 和 Ghd7 等位基因对抽穗期的影响是累加的，PRR37 通过下调 Hd3a 的表达来抑制长日照条件下的开花。我们的研究结果表明，PRR37/Hd2 和 Ghd7/Hd4 的自然变异促进了水稻向温带和凉爽地区的扩展。
