Bryo-THERM Thermomorphogenesis as a mechanism to adapt to elevated temperatures in early land plant evolution

The amplitude between the minimum and the maximum ambient temperature a plant has to endure during its life cycle is much larger in terrestrial than in aquatic environments. As such, especially elevated ambient temperatures are among the most prominent abiotic factors plants had to cope with to successfully colonize land. It is known that the phenotypic plasticity in eudicot land plants allows them to adjust shoot architecture to acclimate and adapt to elevated temperatures. How and when this mechanism, thermomorphogenesis, has originated is unknown. Likewise, we do not know whether bryophytes, whose body plans is probably very similar to that of the first terrestrial plants, perform thermomorphogenesis. In this project, we will therefore characterize the response of bryophytes (Physcomitrella patens and Marchantia polymorpha) to elevated temperatures on both the morphological as well as the physiological level, including elucidation of temperature sensitive signaling cascades. In addition to comparative analyses we will also follow an unbiased approach, primarily using the liverwort Marchantia polymorpha. To identify signaling and response modules, we will generate high density transcriptomic and phosphoproteomic datasets and use them to construct gene regulatory networks based on machine learning approaches. As such, we aim to combine morphological and molecular data in this project to better understand how bryophytes cope with elevated ambient temperatures. With this knowledge. we might then be in a position to design experiments that directly address the emergence of such mechanisms and their role during the terrestrialization of land by plants.