From a monoplastidic ancestor to multifaceted polyplastidy in land plants

陆地植物的细胞，从根到叶组织，有几十个质体。大多数藻类的情况正好相反，它们是单质体的，每个细胞和细胞核都有一个质体。多质体是陆地植物的常态，但藻类是个例外。从单一到多质体的转变在进化中独立地发生了几次，并且似乎使宏观表型成为可能。允许逃离单质体瓶颈的步骤仍然未被探索，但基本上与细胞周期和质体分裂的去同步化有关。陆地植物的祖先是单质体的，现存的链藻藻类也是陆地植物祖先的姐妹。单质体的痕迹在地钱属等扁形植物中很明显。这种常见的苔类植物在孢子发生过程中经历了从多质体到单质体的转变，这样释放的孢子母细胞只携带一个质体。我们推测，这与一个检查点有关，在这个检查点中，健康质体的遗传得到了保证，这也是因为减数分裂只有在质体分裂成功后才开始。我们计划探索在branette中每个细胞中质体数量减少和增加背后的遗传学和机制。我们将特别关注质体分裂装置和相关蛋白（MinD，MinE，FtsZ 1 -3，Drp 5），以及肽聚糖层（及其相关的mur基因）。我们计划通过细胞周期和质体分裂装置的相互作用来研究单质体到多质体的转变（单质体瓶颈）。解除单质体的束缚是高等植物进化的关键步骤，不同类型的质体（原质体、染色体、淀粉质体等）的形成是植物进化的基础。that embryophytes胚植物can mobilize移动.地钱提供了一个很好的模型系统，这既是因为它在多质体和单质体之间的明显过渡是其生命周期的一部分（一个了解细胞器进化和质体遗传的独特窗口），也是因为它很容易操纵核和质体基因组。

The land plant cell, from root to leave tissue, houses dozens of plastids. The contrary is true for the majority of algae that are monoplastidic and house a single plastid per cell and nucleus. Polyplastidy is the norm for land plants, but an exception among algae. The transition from mono- to polyplastidy occurred a few times independently in evolution and appears to enable macroscopic phenotypes. The steps that allow escaping the monoplastidic bottleneck remain unexplored, but are essentially linked to the de-synchronization of the cell cycle and plastid division. The land plant ancestor was monoplastidic, as are extant streptophyte algae sister to the land plant ancestor. Traces of monoplastidy are evident in bryophytes such as Marchantia. This common liverwort undergoes a switch from poly- to monoplastidy during sporogenesis, such that the released sporocytes carry only one plastid. This, we speculate, is associated with a check-point in which inheritance of healthy plastids is guaranteed, also because meiosis only commences upon successful plastid division. We plan on exploring the genetics and mechanisms behind reduction and increase of plastid number per cell in the bryophyte. We will pay particular attention to the plastid division apparatus and involved proteins (MinD, MinE, FtsZ1-3, Drp5), and the peptidoglycan layer (and its related mur genes). We plan on examining the mono- to polyplastiy transition (monoplastidic bottleneck) by the interplay of the cell cycle and the plastid division apparatus. The release from the monoplastidic constrain was a critical step in evolving higher plants and the different types of plastids (pro-, chromo-, amyloplast, etc.) that embryophytes can mobilize. Marchantia offers a great model system, both because of its evident transition between poly- and monoplastidy as part of its life cycle (a unique window into organelle evolution and plastid inheritance), as well as the ease with which both the nuclear and plastid genomes can be manipulated.