The size of plants is largely determined by growth of the stem. Stem elongation is stimulated by gibberellic acid 1 – 3 . Here we show that internode stem elongation in rice is regulated antagonistically by an ‘accelerator’ and a ‘decelerator’ in concert with gibberellic acid. Expression of a gene we name ACCELERATOR OF INTERNODE ELONGATION 1 ( ACE1 ), which encodes a protein of unknown function, confers cells of the intercalary meristematic region with the competence for cell division, leading to internode elongation in the presence of gibberellic acid. By contrast, upregulation of DECELERATOR OF INTERNODE ELONGATION 1 ( DEC1 ), which encodes a zinc-finger transcription factor, suppresses internode elongation, whereas downregulation of DEC1 allows internode elongation. We also show that the mechanism of internode elongation that is mediated by ACE1 and DEC1 is conserved in the Gramineae family. Furthermore, an analysis of genetic diversity suggests that mutations in ACE1 and DEC1 have historically contributed to the selection of shorter plants in domesticated populations of rice to increase their resistance to lodging, and of taller plants in wild species of rice for adaptation to growth in deep water. Our identification of these antagonistic regulatory factors enhances our understanding of the gibberellic acid response as an additional mechanism that regulates internode elongation and environmental fitness, beyond biosynthesis and gibberellic acid signal transduction. Stem growth in rice is regulated by an accelerator gene and a decelerator gene in parallel with gibberellic acid, and the opposite selection of these genes has led to adaptations to different environments.

中文翻译：

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水稻茎秆生长过程中赤霉酸反应的拮抗调控

植物的大小很大程度上取决于茎的生长。赤霉酸 1 – 3 刺激茎伸长。在这里，我们表明水稻节间茎伸长受到“加速器”和“减速器”与赤霉酸协同作用的拮抗调节。我们命名为 ACCELERATOR OF INTERNODE ELONGATION 1 (ACE1) 的基因的表达，它编码一种未知功能的蛋白质，赋予中间分生组织区域的细胞进行细胞分裂的能力，导致在赤霉酸存在下的节间伸长。相比之下，编码锌指转录因子的 DECELERATOR OF INTERNODE ELONGATION 1 (DEC1) 的上调抑制节间伸长，而 DEC1 的下调则允许节间伸长。我们还表明，由 ACE1 和 DEC1 介导的节间伸长机制在禾本科家族中是保守的。此外，对遗传多样性的分析表明，ACE1 和 DEC1 的突变历来有助于在驯化水稻种群中选择较短的植物以增加其抗倒伏性，以及在野生稻种中选择较高的植物以适应深海生长。水。我们对这些拮抗调节因子的识别增强了我们对赤霉酸反应作为调节节间伸长和环境适应性的额外机制的理解，超越了生物合成和赤霉酸信号转导。水稻茎的生长受加速基因和减速基因与赤霉酸平行调控，