Understanding the ancestral function of RCO/LMI1 type homeobox genes in early-divergent land plants.

我们最近发现，晚期分生系统身份1 (Late merisystem Identity 1, LMI1) /降低复杂性（Reduced Complexity， RCO）型同源结构域转录因子参与了一种新的生长调节途径，该途径是种子植物叶片形态进化多样化的基础。与Sabine Zachgo教授一起，我们还获得了LMI1型基因调节多态地茅生长的初步证据。这些发现导致了这样一种假设，即至少这一途径的某些方面可能在地植物中起作用，因此可能代表了对早期陆地植物进化很重要的深度保守功能。为了验证这一假设，我们建议利用遗传学、先进成像和计算模型来表征模型多形地豆中LMI1型基因的功能。我们还建议研究该转录因子在模式苔藓小黄菜中的功能，这将有助于确定LMI1型基因在早期陆地植物生长调节中的功能是否被保守。最后，通过绿藻相关序列的靶向转基因实验，我们将研究生长调节所需蛋白质的结构特征是否在植物定植陆地之前就已经存在，从而可能使这种定植成为可能。

We have recently shown that homeodomain transcription factors of the Late Meristem Identity 1 (LMI1) / Reduced Complexity (RCO) type participate in a novel growth regulating pathway that underlies evolutionary diversification of leaf form in seed plants. Together with Prof. Sabine Zachgo, we have also obtained preliminary evidence that an LMI1 type gene regulates growth in the liverwort Marchantia polymorpha. These findings lead to the hypothesis that at least some aspects of this pathway may operate in liverworts and therefore may represent deeply conserved functions that were important for early land plant evolution. To test this hypothesis, we propose to characterize the function of LMI1 type genes in the model Marchantia polymorpha using genetics, advanced imaging and computational modelling. We also propose to investigate functions of this transcription factor in the model moss Physchomitrella patens which will help pinpoint if aspects of LMI1 type gene function in growth regulation were conserved in early land plants. Finally, through targeted transgenic experiments with related sequences from green algae, we will aim to investigate whether structural features of the protein necessary for growth regulation were already present before plants colonized land and therefore may have enabled this colonization.