Shaping fruit morphogenesis of flowering plants by elucidating heart-shaped fruit development in capsella rubella
The flowering plants (angiosperms) evolved over 100 million years ago and quickly colonized every habitable corner of the planet. Such success hinges largely on the formation of fruits that protect and nurture the developing seeds. Moreover, a massive range of diversity in fruit shape arose during a relatively short time, which allowed for the development of ingenious ways of fertilisation as well as strategies for efficient seed dispersal. The Brassicaceae family contains a wealth of diversity in fruit morphologies and includes some of our genetically best characterised model plants and important crop species. Thus, the Brassicaceae family provides an ideal group of plants to study how specific shapes are established. Although many genes controlling fruit patterning in the model plant Arabidopsis thaliana have been identified, processes leading to specific fruit morphologies are still poorly understood. To unravel these processes, I will study fruit shape using the heart-shaped fruits from Capsella rubella as a model system to unravel molecular mechanisms by which growth is oriented and coordinated to generate this shape. I will exploit a panel of Capsella fruit-shape mutants including the heartless (htl) mutant, which encodes a putative orthologue of the Arabidopsis ANGUSTIFOLIA (AN) protein. To investigate the molecular mechanism by which the HTL/AN protein controls fruit shape formation in Capsella, I will characterize the interacting proteins of HTL by immunoprecipitation followed by mass spectrometry analysis. Novel genetic regulators of fruit shape will be identified and I will study their role in fruit development using biochemical, molecular and genetic analyses. Beyond the elucidation of how the genetic network is established to control anisotropic growth during development, the work described in this proposal will provide new directions for shaping seed and fruit crops for enhanced performance.