Laboratory of Molecular Biology of Tomato, Bioengineering College, Chongqing University, Chongqing, People's Republic of China.
School of Life Sciences, Zhengzhou University, Zhengzhou 450001, People's Republic of China.
Plant Sci. 2018 Jun;271:81-93. doi: 10.1016/j.plantsci.2018.03.017. Epub 2018 Mar 21.
Previous studies suggest that GRAS transcription factors act as essential regulators, not only in plant growth and development but also in response to biotic and abiotic stresses. Recently, 53 GRAS proteins have been identified, but only a few of them have been functionally studied in tomato. Here, we isolated a novel GRAS transcription factor SlGRAS26, its down-regulation generated pleiotropic phenotypes, including reduced plant height with more lateral shoots, internode length, leaf size, even leaflets, accelerated flowering transition and decreased trichome number. Transcription analysis showed that down-regulation of SlGRAS26 altered vegetative growth by suppressing gibberellin (GA) biosynthesis genes and activating the GA inactivating genes, thereby reducing endogenous GA content in transgenic plants. SlGRAS26 may regulate the initiation of lateral buds by regulating the expression of Blind (BL) and BRC1b. The earlier initiation of flower buds in transgenic lines may be controlled by significant up-regulation of SFT, CO1, SBP3, SBP13, and SBP15 genes, related to flowering time. These results demonstrate that SlGRAS26 may play a vital role in the initiation of lateral and inflorescence meristems in tomato.
先前的研究表明，GRAS 转录因子不仅在植物生长发育过程中，而且在生物和非生物胁迫反应中，都作为重要的调控因子发挥作用。最近，已经鉴定出 53 种 GRAS 蛋白，但其中只有少数几种在番茄中进行了功能研究。在这里，我们分离到一个新的 GRAS 转录因子 SlGRAS26，其下调导致了多种表型，包括植株变矮，侧枝增多，节间长度、叶片大小、甚至小叶减少，开花时间提前，毛状体数量减少。转录分析表明，SlGRAS26 通过抑制赤霉素（GA）生物合成基因和激活 GA 失活基因来抑制植物生长，从而降低转基因植物中的内源 GA 含量。SlGRAS26 可能通过调节 Blind（BL）和 BRC1b 的表达来调节侧芽的起始。转基因株系中花蕾更早开始可能是由于与开花时间相关的 SFT、CO1、SBP3、SBP13 和 SBP15 基因的显著上调所控制。这些结果表明，SlGRAS26 可能在番茄侧芽和花序分生组织的起始中发挥重要作用。
