Seminars

In this talk, I will first summarise the recent advances in the development of Anthoceros agrestis as the first hornwort experimental system [1-4] and give a few examples of how we start using A. agrestis to better understand plant evolution and biology in general. I will then discuss how we used the liverwort Marchantia polymorpha, as a platform to identify and characterise a class of transcription factors, RR-MYBs, as novel master regulators of chloroplast biogenesis in land plants. Chloroplast biogenesis is primarily regulated by nucleus-encoded transcription factors. Despite extensive research over the past decades, our understanding of the genetic network underlying this process remains incomplete. Apart from the well-characterised Golden2-like (GLK) and GATA transcription factor families, no other regulators are known. While GLK and GATA are considered central to chloroplast biogenesis and photosynthesis, the presence of functional chloroplasts in glk, gata, or glk&gata mutants suggests the existence of additional, yet unidentified, regulatory pathways. We used Marchantia polymorpha, which possesses a streamlined genome, to uncover novel regulators of chloroplast development. Through this approach, we successfully identified a pair of RR-MYB-related transcription factors that play a critical role in chloroplast biogenesis [5] in M.polymorpha. Importantly, we found that the function of these RR-MYB-related transcription factors is conserved in the angiosperm Arabidopsis thaliana, suggesting that their role in chloroplast biogenesis is likely ancestral and broadly conserved across land plants.