National Key Laboratory of Crop Genetic Improvement, National Center of Plant Gene Research-Wuhan, Huazhong Agricultural University, Wuhan 430070, China.
Mol Plant. 2013 Jan;6(1):202-15. doi: 10.1093/mp/sss062. Epub 2012 Aug 10.
Heading date is a critical trait that determines cropping seasons and regional adaptability in rice (Oryza sativa). Research efforts during the last decade have identified some important photoperiod pathway genes that are conserved between Arabidopsis and rice. In this study, we identified a novel gene, Oryza sativa ELF3 (OsELF3), which is a putative homolog of the ELF3 gene in Arabidopsis thaliana. OsELF3 was required for the control of heading date under long-day conditions. Its Tos17-tagging mutants exhibited a delayed heading date phenotype only under long-day, but not short-day, conditions. OsELF3 was highly expressed in leaf blades, and the OsELF3 protein was localized in the nucleolus. An obvious diurnal rhythm of OsELF3 transcript level was observed, with a trough in the early day and a peak in the late night in wild-type plants. However, this expression pattern was disrupted in oself3 mutants. Further investigations showed that the expression of OsGI and Ghd7 was up-regulated in the oself3 mutant, indicating that OsELF3 acts as a negative regulator upstream of OsGI and Ghd7 in the flowering-time control under long-day conditions. The rhythmic expression of circadian clock-related genes, including some OsPRR members, was obviously affected in oself3 mutants. Our results indicated that OsELF3 acts as a floral activator in the long-day photoperiodic pathway via its crosstalk with the circadian clock in rice.
Heading date 是一个关键的特征，它决定了水稻（Oryza sativa）的种植季节和区域适应性。在过去的十年中，研究工作已经确定了一些重要的光周期途径基因，这些基因在拟南芥和水稻之间是保守的。在这项研究中，我们鉴定了一个新的基因，Oryza sativa ELF3（OsELF3），它是拟南芥 ELF3 基因的假定同源物。OsELF3 是控制长日条件下抽穗期的必需基因。其 Tos17 标记突变体仅在长日条件下表现出抽穗期延迟的表型，而在短日条件下则没有。OsELF3 在叶片中高度表达，并且 OsELF3 蛋白定位于核仁中。在野生型植物中，观察到 OsELF3 转录本水平的明显昼夜节律，在早期有一个低谷，在深夜有一个高峰。然而，在 oself3 突变体中，这种表达模式被打乱了。进一步的研究表明，在 oself3 突变体中，OsGI 和 Ghd7 的表达上调，表明 OsELF3 在长日条件下作为开花时间控制的上游负调节因子，作用于 OsGI 和 Ghd7。一些 OsPRR 成员等生物钟相关基因的节律表达在 oself3 突变体中明显受到影响。我们的结果表明，OsELF3 通过与水稻生物钟的相互作用，作为长日光周期途径中的花激活因子发挥作用。
