The amphibious liverwort Riccia fluitans:A novel model organism to analyze adaptive land plant features

已知的TCP转录因子在被子植物发育过程中发挥着重要的调节功能。最近，我们检测到多态地钱TFMpTCP1具有生长调节功能，并调控新的植物色素的形成，这些色素可能介导对非生物胁迫的保护功能。植物陆地化可能始于淡水环境，在那里陆地植物的祖先经历了缺水。因此，第一批陆地植物面临着新的非生物胁迫，如干旱和高光强。为了研究能够征服陆地的适应分子机制，新兴的模式生物Riccia flitans非常适合，因为这种两栖苔类可以在水生和陆地生境中挣扎。由于其惊人的发育可塑性，这种苔类植物可以适应不同的生境。水的干燥会导致典型的陆地植物结构的形成：作为锚定结构的根状结构，用于气体交换的气孔和驱避性表面。我们将通过产生和研究CRISPR/Cas9诱导的突变体来改进RfTCP1的工具箱，并分析RfTCP1的活性。水和陆地的分生组织活动也不同，从而调节了藻体生长的差异。氧化还原敏感的MpTCP1蛋白活性控制着复杂的下游氧化还原网络，也影响生长。我们的目标是研究氧化还原过程对分生组织活动和适应陆地植物特征的形成的影响，以及在变化的、具有挑战性的环境中的影响。

TCP transcription factors (TFs) are known to exert crucial regulatory functions in angiosperm development. Recently, we detected that the Marchantia polymorpha TF MpTCP1 exhibits a growth regulatory function and also governs the formation of novel plant pigments, which might mediate protective functions against abiotic stress. Plant terrestrialization likely started from a freshwater environment, where ancestors of land plants experienced water scarcity. The first land plants were thus facing novel abiotic stressors such as drought and high light intensities. To investigate adaptive molecular mechanisms enabling the conquest of land, the emerging model organism Riccia fluitans is ideally suited, as this amphibious liverwort can strive in aquatic as well as terrestrial habitats. Given its striking developmental plasticity, this liverwort can adapt thallus development to different habitats. Desiccation of the R. fluitans water form causes the formation of typical land plant structures: rhizoids as anchoring structures, air pores for gas exchange and a repellent surface. We will advance the tool box for R. fluitans and analyze the RfTCP1 activities by generating and investigating CRISPR/Cas9-induced mutants. The R. fluitans water and land forms also differ in their meristematic activities, thereby mediating thallus growth differences. The redox-sensitive MpTCP1 protein activity controls a complex downstream redox network, affecting also growth. We aim to investigate the impact of redox processes on meristematic activities and the formation of adaptive land plant features and in changing, challenging environments.