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

植物分化出特殊的细胞类型、组织和器官，这些细胞类型、组织和器官对它们的光合作用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、多能的祖细胞。在个体发育过程中，一小群干细胞被维持在特定的位置，即所谓的干细胞壁龛。这种生态位存在于根、茎和维管分生组织中的植物中。在这些干细胞的利基环境中，一组精确平衡的调节因子确保了未分化的、多潜能的状态得以维持，同时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microRNAs。我们的关键假设是，复杂陆地植物形态背后的机制是在轮藻的特定成员中进化的，并且通过表征特定调控因子的分子功能，有可能跟踪进化过程。因此，该项目遵循这样的假设，即这些调控机制的出现在早期陆地植物进化中具有核心重要性。我们将重点放在Brauni轮藻模型上，但与在其他藻类和陆地植物模型中获得的洞察力进行比较，如拟南芥和丛生植物。在布氏轮虫中，结节中央细胞是多能细胞的候选细胞，其特征将在单细胞水平上进行。然后，我们将研究某些调节因子在控制细胞和叶绿体分化中的作用，并跟踪对选定的非生物胁迫的调节反应。虽然重点放在轮藻上，但基于公开可用的数据集，特别是通过SPP内部的合作，与苔藓和蕨类数据的系统比较将会取得进展。此外，我们将为基因表达数据集和RNA：RNA相互作用和轮藻材料和培养的分析提供生物信息学专业知识，从而加强整个财团的技术诀窍。

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.