Understanding developmental processes in early-diverging plant model systems

• Main Author: Vesty, Eleanor Fay
• Published: University of Birmingham 2017
• Subjects: 571.8; QH301 Biology
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.715638

The study of evolutionary developmental biology relies on a detailed understanding of model systems. Whilst the flowering plants are the most successful and valuable plant group today, they don’t tell us much about the change and progression that was initiated by an ancestral aquatic photosynthetic unicell millions of years ago. The expansion of bryophyte and algal model systems was developed as part of this research The moss \(Physcomitrella\) \( patens\) is descended from the ancestral bryophytes that first colonised land. As such it is well-placed, as a model organism, to provide insight into terrestrialisation. The germination of spores or seeds is one of the key stages in the land plant life cycle. Comparison of the influences on spore and seed germination provides insight into the conservation of functions spanning 450 million years of evolution. The role of phytohormones in the control of spore germination was assessed by analysing the response of \(P. patens\) spores to different exogenously applied hormones. Endogenous roles were explored using hormone biosynthesis mutants and semi-quantitative analysis of signalling genes. This research shows that \(P. patens\) spore germination is regulated by some of the same hormones that regulate seed germination. The extent of regulation varies between hormone types but this has demonstrated previously unknown characteristics of the \(P. patens\) hormone signalling network. This work also highlights the importance of establishing tractable model systems with robust methodological procedures.