Unravelling the molecular mechanisms of monocot embryogenesis
Plant Genetics and Genomics
Final Report Abstract
One key question in plant biology is how a single-celled zygote develops into a functional organism consisting of different tissues and organs. Knowledge on axis formation and meristem specification during embryogenesis in plants has tremendously advanced in the last two decades having adopted the dicot plant Arabidopsis thaliana as a model organism. The mature seeds of monocot plants dis-play dramatic different structures than those of dicot plants. However, how these structures are patterned during embryogenesis is largely unknown. Thus, while much has been learnt from studying Arabidopsis embryogenesis, it is currently not clear if any concepts can be directly transposed to monocot embryogenesis. This underlines the urgency to study monocot embryogenesis. We took a monocot grass, Brachypodium distachyon as a model to systematically study monocot embryogenesis, especially for understanding early patterning events, such as formation of the primary axis and specification of the meristem. This will greatly increase our knowledge on tissue specification and organ formation in monocots and broaden our understanding of the biological diversity of plant early development. In addition, it will provide the basis for future investigation of crucial genetic inter-actions between individual seed compartments (seed coat, embryo, and endosperms). So far we have A) partially obtained the developmental atlas by segmenting the early stages of Brachypodium embryos using MorphoGraphX; B) set up a working transformation system in the lab as a basis for developing the genetic tools needed for studying monocot embryogenesis; C) analysed the expression of auxin-related reporter lines. From the current results, the question of whether the auxin signaling pathway plays a role in apical and basal axis formation during monocot embryogenesis remains open. Based on the results thus far, we did see the potential of Brachypodium as a monocot model species and observed initial differences between dicot and monocot in embryo patterning, which would raise scientific attention to further investigate this direction.
