Evolution of the regulatory networks governing developmental adaptations and acclimation responses in Charophycean green algae towards plant life on land

植物分化出专门的细胞类型、组织和器官，这些细胞类型、组织和器官对于它们的光合生活方式和在各自的生态位中茁壮成长至关重要。所有分化的细胞最终都来自干细胞，即未分化的多能祖细胞。在个体发育过程中，小群体的干细胞保持在某些位置，即所谓的干细胞龛。这种生态位存在于植物的根、茎和维管分生组织中。在这些干细胞小生境中，一组精确平衡的调节因子确保维持未分化的多能状态，而外围的细胞能够进入特定的分化途径。为了控制细胞分化状态，植物具有多种机制，包括专门的转录因子和microRNA。我们的主要假设是，复杂的陆地植物形态的机制在轮藻的特定成员中进化，并且通过表征特定调节子的分子功能，可以跟踪进化过程。因此，该项目遵循的假设，这些监管机制的出现是至关重要的早期陆地植物进化。我们将专注于轮藻braunii模型，但在其他藻类和陆地植物模型，如拟南芥和立碗藓的洞察力进行比较。在布朗轮藻中，结节中央细胞是多能细胞的候选者，这将在单细胞水平上表征。然后，我们将调查的作用，某些监管机构在控制细胞和叶绿体分化，并按照选定的非生物胁迫的监管反应。虽然重点是轮藻，但基于公开的数据集，特别是通过SPP内部的合作，将推进与苔藓和蕨类植物数据的系统比较。此外，我们将提供生物信息学专业知识，用于分析基因表达数据集和RNA：RNA相互作用以及Chara braunii材料和培养物，从而加强整个联盟的专业知识。

Plants differentiate specialized cell types, tissues, and organs that are fundamental to their photosynthetic lifestyle and for thriving in their respective ecological niches. All differentiated cells ultimately descend from stem cells, undifferentiated, pluripotent progenitors. During ontogenesis, small groups of stem cells are maintained at certain positions, the so-called stem cell niches. Such niches exist in plants within the root, shoot and vascular meristems. In these stem cell niches, a precisely balanced set of regulatory factors ensures that the undifferentiated, pluripotent state is maintained, while cells at the periphery are able to enter specific differentiation pathways. To control cell differentiation status, plants possess multiple mechanisms that include specialized transcription factors and microRNAs. Our key hypothesis is that the mechanisms underlying the complex land plant morphologies evolved in specific members of the charophytes, and that by characterization of specific regulators’ molecular functions it is possible to track the evolutionary process. Therefore, this project follows the hypothesis that the emergence of these regulatory mechanisms was of central importance in early land plant evolution. We will focus on the Chara braunii model but compare to insight obtained in other algae and land plant models such as Arabidopsis and Physcomitrium. In Chara braunii, nodal central cells are candidates for pluripotent cells, which will be characterized at single-cell level. We will then investigate the role of certain regulators in controlling cellular and chloroplast differentiation and follow the regulatory responses to selected abiotic stresses. While the focus is on charophytes, the systematic comparison with data from mosses and ferns will advance, based on publicly available datasets and in particular through collaborations within the SPP. In addition, we will provide bioinformatics expertise for the analysis of gene expression datasets and RNA:RNA interactions and Chara braunii material and cultures, thereby strengthening the know-how of the consortium as a whole.