State Key Laboratory of Genetic Engineering, Institute of Genetics, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, China.
Plant Biotechnol J. 2013 Dec;11(9):1044-57. doi: 10.1111/pbi.12097. Epub 2013 Aug 7.
Common wild rice (Oryza rufipogon Griff.) is an important genetic reservoir for rice improvement. We investigated a quantitative trait locus (QTL), qGP5-1, which is related to plant height, leaf size and panicle architecture, using a set of introgression lines of O. rufipogon in the background of the Indica cultivar Guichao2 (Oryza sativa L.). We cloned and characterized qGP5-1 and confirmed that the newly identified gene OsEBS (enhancing biomass and spikelet number) increased plant height, leaf size and spikelet number per panicle, leading to an increase in total grain yield per plant. Our results showed that the increased size of vegetative organs in OsEBS-expressed plants was enormously caused by increasing cell number. Sequence alignment showed that OsEBS protein contains a region with high similarity to the N-terminal conserved ATPase domain of Hsp70, but it lacks the C-terminal regions of the peptide-binding domain and the C-terminal lid. More results indicated that OsEBS gene did not have typical characteristics of Hsp70 in this study. Furthermore, Arabidopsis (Arabidopsis thaliana) transformed with OsEBS showed a similar phenotype to OsEBS-transgenic rice, indicating a conserved function of OsEBS among plant species. Together, we report the cloning and characterization of OsEBS, a new QTL that controls rice biomass and spikelet number, through map-based cloning, and it may have utility in improving grain yield in rice.
普通野生稻（Oryza rufipogon Griff.）是改良水稻的重要遗传资源库。我们利用一套以籼稻品种桂朝 2 号（Oryza sativa L.）为背景的普通野生稻导入系，研究了一个与株高、叶面积和穗型结构有关的数量性状位点（QTL）qGP5-1。我们克隆并鉴定了 qGP5-1，并证实新鉴定的基因 OsEBS（增强生物量和小穗数）增加了株高、叶面积和每穗小穗数，从而增加了每株植物的总粒产量。研究结果表明，OsEBS 表达植株中营养器官的增大主要是由于细胞数量的增加。序列比对表明，OsEBS 蛋白含有一个与 Hsp70 的 N 端保守 ATP 酶结构域高度相似的区域，但它缺乏肽结合域的 C 端区域和 C 端盖。更多的结果表明，在本研究中，OsEBS 基因没有典型的 Hsp70 特征。此外，拟南芥（Arabidopsis thaliana）转化 OsEBS 后表现出与 OsEBS 转基因水稻相似的表型，表明 OsEBS 在植物物种中具有保守功能。总之，我们通过图谱克隆报告了 OsEBS 的克隆和鉴定，这是一个新的控制水稻生物量和小穗数的 QTL，它可能在提高水稻产量方面具有应用价值。
