The role of ethylene in drought-induced leaf growth repression and cell cycle inhibition

Leaf growth is a complex developmental process that is tightly regulated to react dynamically to
changing environmental conditions. Under drought stress, leaf growth is reduced to limit the
evaporative surface and save energy. In the last years, research conducted on Arabidopsis and
crops highlighted a role for the phytohormone ethylene in the regulation of cell division, leaf
growth and yield under drought. Nevertheless, the molecular mechanisms underlying this process
remain largely elusive. With the proposed project, I aim to unravel the role of ethylene in leaf
growth inhibition under drought. By using cutting-edge technologies and last-generation genetic
tools, both made available through international collaborations, I will measure and understand the
ethylene accumulation in leaves under drought. Next, I will elucidate at the molecular level how
ethylene triggers downstream pathways for leaf growth inhibition. Automated phenotyping on a
broad range of ethylene mutants and transgenic lines with reduced ethylene levels will enable to
pinpoint key genes and mechanisms involved in leaf growth inhibition under drought. Finally, by
performing cell type-specific transcriptome analysis in leaves using the INTACT technology, I will
aim to model how ethylene mediates cell cycle arrest under drought. With this novel and
multidisciplinary approach, we will significantly enhance our current view on the molecular
pathways enabling phenotypic plasticity under adverse conditions.