Department of Plant Sciences, University of Hyderabad, Hyderabad-500046, India.
Department of Crop Physiology, University of Agricultural Sciences-GKVK, Hebbal, Bangalore, India.
Sci Rep. 2017 Feb 23;7:42835. doi: 10.1038/srep42835.
The target of Rapamycin (TOR) present in all eukaryotes is a multifunctional protein, regulating growth, development, protein translation, ribosome biogenesis, nutrient, and energy signaling. In the present study, ectopic expression of TOR gene of Arabidopsis thaliana in a widely cultivated indica rice resulted in enhanced plant growth under water-limiting conditions conferring agronomically important water-use efficiency (WUE) trait. The AtTOR high expression lines of rice exhibited profuse tillering, increased panicle length, increased plant height, high photosynthetic efficiency, chlorophyll content and low ∆C. ΔC, which is inversely related to high WUE, was as low as 17‰ in two AtTOR high expression lines. These lines were also insensitive to the ABA-mediated inhibition of seed germination. The significant upregulation of 15 stress-specific genes in high expression lines indicates their contribution to abiotic stress tolerance. The constitutive expression of AtTOR is also associated with significant transcriptional upregulation of putative TOR complex-1 components, OsRaptor and OsLST8. Glucose-mediated transcriptional activation of AtTOR gene enhanced lateral root formation. Taken together, our findings indicate that TOR, in addition to its multiple cellular functions, also plays an important role in response to abiotic stress and potentially enhances WUE and yield related attributes.
雷帕霉素靶蛋白（TOR）存在于所有真核生物中，是一种多功能蛋白，调节生长、发育、蛋白质翻译、核糖体生物发生、营养和能量信号。在本研究中，拟南芥 TOR 基因在广泛种植的籼稻中的异位表达导致在限水条件下增强植物生长，赋予了具有重要农艺意义的水分利用效率（WUE）特性。水稻 AtTOR 高表达系表现出旺盛的分蘖、增加的穗长、增加的株高、高光合效率、叶绿素含量和低的 ∆C。∆C 与高 WUE 呈反比，在两个 AtTOR 高表达系中低至 17‰。这些系也对 ABA 介导的种子萌发抑制不敏感。高表达系中 15 个应激特异性基因的显著上调表明它们对非生物胁迫耐受性的贡献。AtTOR 的组成型表达也与假定的 TOR 复合物-1 成分 OsRaptor 和 OsLST8 的转录显著上调有关。葡萄糖介导的 AtTOR 基因转录激活促进了侧根的形成。总之，我们的研究结果表明，TOR 除了具有多种细胞功能外，还在应对非生物胁迫方面发挥重要作用，并可能增强 WUE 和与产量相关的特性。
