Origin of Gibberellin-Dependent Transcriptional Regulation by Molecular Exploitation of a Transactivation Domain in DELLA Proteins
Origin of Gibberellin-Dependent Transcriptional Regulation by Molecular Exploitation of a Transactivation Domain in DELLA Proteins
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DOI：
10.1093/molbev/msz009
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发表时间：
2019-05-01
影响因子：
10.7
通讯作者：
Blazquez, Miguel A.
中科院分区：
文献类型：
--
作者：
Hernandez-Garcia, Jorge;Briones-Moreno, Asier;Blazquez, Miguel A.
Della蛋白是植物特有的转录调控因子，通过其C-末端GRAS结构域与拟南芥中150多个转录因子相互作用。此外，维管植物的DELLA可以通过N-末端结构域与GID1编码的赤霉素受体相互作用，赤霉素通过GID1促进DELLA的降解。然而，这种调节在非维管束陆地植物中是不存在的，因为它们缺乏活性的赤霉素或适当的GID1受体。目前的知识表明，Della是维管植物，特别是被子植物信号机制的重要组成部分，但在早期陆地植物进化过程中，人们对Della的功能知之甚少，也不知道它们是否存在于轮藻中。我们现在已经阐明了Della蛋白的进化起源，表明藻类GRAS蛋白是单系进化的，独立于陆地植物的进化，这解释了为什么在陆地植物之外没有Della蛋白。Della基因在陆地植物进化过程中一直保持不变，只有两个主要的复制事件在植物之间保留。此外，我们发现DELLA与受体相互作用所需的特征已经存在于所有陆地植物的祖先中，并认为这些DELLA N末端基序在非维管植物中由于其在转录共激活中的功能而被紧密保守，这使得当维管植物发育成赤霉素合成和相应的感知模块时，这些基序能够在随后与GID1受体的相互作用中激活。
DELLA proteins are plant-specific transcriptional regulators known to interact through their C-terminal GRAS domain with over 150 transcription factors in Arabidopsis thaliana. Besides, DELLAs from vascular plants can interact through the N-terminal domain with the gibberellin receptor encoded by GID1, through which gibberellins promote DELLA degradation. However, this regulation is absent in nonvascular land plants, which lack active gibberellins or a proper GID1 receptor. Current knowledge indicates that DELLAs are important pieces of the signaling machinery of vascular plants, especially angiosperms, but nothing is known about DELLA function during early land plant evolution or if they exist at all in charophytan algae. We have now elucidated the evolutionary origin of DELLA proteins, showing that algal GRAS proteins are monophyletic and evolved independently from those of land plants, which explains why there are no DELLAs outside land plants. DELLA genes have been maintained throughout land plant evolution with only two major duplication events kept among plants. Furthermore, we show that the features needed for DELLA interaction with the receptor were already present in the ancestor of all land plants and propose that these DELLA N-terminal motifs have been tightly conserved in nonvascular land plants for their function in transcriptional coactivation, which allowed subsequent exaptation for the interaction with the GID1 receptor when vascular plants developed gibberellin synthesis and the corresponding perception module.