Seed Genomics
Seed Genomics
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种子基因组学
DOI：
10.1002/9781118525524.ch2
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
Fonseka D
中科院分区：
文献类型：
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作者：
Fonseka D
拟南芥胚已成为研究植物发育关键方面的重要参考系统。在生物学上，胚胎代表了植物生命周期的一个阶段，在这个阶段，植物体结构组织的关键特征——尖基极性和径向对称——得以建立。与动物胚胎相比，植物胚胎不是一个微型的成体。它不包含成熟植物中发现的许多器官。在拟南芥中，胚胎特别简单，只有根、子叶和下胚轴。其他物种的胚胎，如玉米，在发芽前有一定的叶片发育，但拟南芥胚胎的特点是两个发育轴重叠，即顶基轴和径向轴。一个不寻常的特征是，拟南芥胚胎中的细胞分裂模式是高度定型和可预测的，这使得可以随时识别扰乱细胞模式机制的基因突变（图2.1）（Mansfield和Briarty, 1991; j<s:1> rgens等，1994）。拟南芥胚胎发生在所有高等双子叶植物中并不特别典型，但其遗传易变性已经导致控制细胞模式和轴发育的分子机制的揭示，其中许多可能在植物物种之间保守。这些分子控制机制是本章的重点。我们考虑了正确胚胎发生所需的基因和调节这些基因的时空表达的信号系统。我们不考虑胚乳的发育，胚乳的发育虽然可能影响胚胎发生，但对胚胎发生并不重要，至少在发育的最初阶段是这样。第三章详细讨论了胚乳。此外，我们无法描述所有已知参与胚胎发生过程的基因的功能。相反，我们关注的是激素信号系统（尤其是但不限于生长素信号系统），以及这些信号系统如何被用于激活特定组织中的基因，以及它们本身如何受到特定基因功能的影响，以创建功能调节网络。
The embryo of Arabidopsis thaliana has become an important reference system in which to study key aspects of plant development. Biologically, the embryo represents the phase of the plant life cycle during which key features of the structural organization of the plant body are established–apical-basal polarity and radial symmetry. In contrast to the animal embryo, the plant embryo is not a miniature adult. It does not contain many organs found in the mature plant. In Arabidopsis, the embryo is especially simple, with only a root, cotyledons, and hypocotyl present. Embryos of other species, such as Zea mays, have some leaf development in advance of germination, but the Arabidopsis embryo is characterized by the superimposition of two developmental axes, the apicalbasal and the radial. An unusual feature is that the pattern of cell divisions in the Arabidopsis embryo is highly stereotyped and predictable, and this allows the ready identification of genetic mutations that perturb cell patterning mechanisms (Figure 2.1)(Mansfield and Briarty, 1991; Jürgens et al., 1994). Arabidopsis embryogenesis is not especially typical of all higher dicotyledonous plants, but its genetic tractability has led to the unraveling of molecular mechanisms that control cell patterning and axis development, and many of these are likely to be conserved between plant species. These molecular control mechanisms are the focus of this chapter. We consider what is known about the genes necessary for correct embryogenesis and the signaling systems that regulate the temporal and spatial expression of those genes. We do not consider the development of the endosperm, which, although it may influence embryogenesis, is not critical for it, at least at the earliest stages of development. The endosperm is considered in detail in Chapter 3. Also, we are unable to describe the functions of all genes known to be involved in the embryogenic process. Rather, we focus on hormone signaling systems (especially but not exclusively auxin signaling) and how these are used to activate genes in particular tissues as well as how they are themselves influenced by the functions of specific genes to create functional regulatory networks.