Transcriptional Regulation of Zygote Asymmetry in Arabidopsis thaliana

拟南芥合子不对称性的转录调控

• 批准号: 392561620
• 负责人: Professor Dr. Thomas Laux
• 金额: --
• 依托单位: Institut für Biologie III
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/392561620?language=en
• 关键词: Transcriptional; Regulation; Zygote; Asymmetry; Arabidopsis

One of the fundamental steps in plant development is the generation of the two precursor cells for embryo and suspensor from a single-celled zygote. In many species, including the model plant Arabidopsis, the zygote is polarized and undergoes an asymmetric division that generates these two cells of different morphologies and fates and makes the apical-basal (shoot-root) axis of the future plant evident. Unlike in animals, plant zygotes are transcriptionally active including genes regulating its polarity and asymmetric division. This implies that plants must have evolved mechanisms to activate zygote-specific transcription programs after fertilization that govern early embryo patterning. During the last funding period, we demonstrated that this activation process requires the collaboration of transcriptional information provided by each parent. From the paternal side, sperm-delivered mRNA of the SHORT SUSPENSOR (SSP) membrane protein triggers the phosphorylation of the transcription factor WRKY2, which is required for polar localization of nucleus and vacuoles in the zygote and subsequently for its asymmetric division. These functions are mediated by direct transcriptional up-regulation of the master patterning gene WUSCHEL HOMEOBOX8 (WOX8) after fertilization. We further discovered the transcription factors HOMEODOMAIN GLABROUS11/12 (HDG11/12) as novel maternal regulators of zygote asymmetry that also directly regulate WOX8 transcription. These results reveal a framework of how maternal and paternal factors are integrated in the zygote to regulate embryo patterning. The goal of this proposal is to gain insight into how these processes are regulated. First, we will analyze how protein-protein interaction between WRKY2 and HDG11/12 contribute regulation of zygote asymmetry. Second, we will address how transcriptional activation of WOX8 is confined to the zygote and its basal descendants but inhibited in postembryonic tissue. Third, we will explore how transcriptional programs in the zygote translate into developmental phenotypes. To investigate these questions, we will combine genetic, biochemistry and molecular biology approaches. In addition to our recently published finding, we have already done extensive preparatory work for this proposal, including transcriptome analysis, interaction studies and preparation of molecular tools, enabling a swift start of the proposed experiments.We expect that this work will provide significant advances in understanding the initiation of transcriptional programs in the zygote and their impact on early embryo development. In a broader context, we are collaborating with international laboratories to apply the obtained knowledge for improving regeneration strategies of economically important plants through somatic embryo formation.

植物发育的基本步骤之一是由单细胞合子产生胚和胚柄两个前体细胞。在许多物种中，包括模式植物拟南芥，受精卵是极化的，并经历不对称分裂，产生这两个细胞的不同形态和命运，使未来植物的顶端-基部（茎-根）轴明显。与动物不同，植物合子是转录活性的，包括调节其极性和不对称分裂的基因。这意味着植物必须进化出机制，在受精后激活受精卵特异性转录程序，控制早期胚胎的模式。在上一个资助期间，我们证明了这个激活过程需要每个父母提供的转录信息的合作。从父本侧，精子传递的短悬浮体（SSP）膜蛋白的mRNA触发转录因子WRKY 2的磷酸化，这是受精卵中细胞核和液泡的极性定位以及随后的不对称分裂所必需的。这些功能是通过受精后主模式基因WUSCHEL HOMEOBOX 8（WOX 8）的直接转录上调介导的。我们进一步发现了转录因子同源域Glabrous 11/12（HDG 11/12）作为受精卵不对称性的新的母体调节因子，其也直接调节WOX 8转录。这些结果揭示了一个框架，母亲和父亲的因素是如何整合在受精卵调节胚胎图案。本提案的目标是深入了解这些过程是如何受到监管的。首先，我们将分析WRKY 2和HDG 11/12之间的蛋白质-蛋白质相互作用如何促进合子不对称性的调节。其次，我们将讨论如何转录激活WOX 8被限制在受精卵和其基础的后代，但在胚后组织抑制。第三，我们将探讨受精卵中的转录程序如何转化为发育表型。为了研究这些问题，我们将结合联合收割机遗传学，生物化学和分子生物学的方法。除了我们最近发表的发现，我们已经做了大量的准备工作，包括转录组分析，相互作用的研究和分子工具的准备，使拟议的实验能够迅速开始，我们希望这项工作将提供显着的进展，了解转录程序的启动在受精卵和它们对早期胚胎发育的影响。在更广泛的背景下，我们正在与国际实验室合作，通过体细胞胚形成应用所获得的知识来改善经济重要植物的再生策略。