How plants grow from a small seed to their final stature appeals to the imagination of many people.
Plants are indispensable for our daily needs, therefore, it is crucial to understand the mechanisms
that drive plant growth and identify molecular links between genes that enhance final organ size. In
this project, we will study the central growth regulator DA2. DA2 limits leaf and seed size in
Arabidopsis and rice and its inactivation leads to larger plant organs. Recently, modifiers of the
enlarged da2-1 phenotype were discovered, suggesting a genetic link between these genes. Most
probably, DA2 modifies positive regulators of growth, but these remain unknown. By combining
getetic and proteomic approaches, we will identify these substrates of DA2. Next, we will find out
what happens to those proteins after they are modified by DA2 (they can be degraded, for
example). To reveal their role in leaf growth and senescence, we will quantify if mutants with an
altered expression show changes in leaf and seed size in Arabidopsis and rice and characterize the
downstream molecular pathways. This project will reveal new regulators of growth and uncover
new molecular links between known growth regulating genes. This way, our current view on how
plant organs reach their final size will be significantly enhanced.