SHEDDING LIGHT ON THE MATURATION OF CLAVATA PROTEINS – KEY REGULATORS WITH A CRITICAL ROLE IN STEM CELL MAINTENANCE AND DEVELOPMENTAL PLASTICITY

Plants have the unique capacity of generating new tissues and organs for their entire lives starting from populations of pluripotent cells enclosed in Apical Meristems. These stem cell niches - able to differentiate new structures both above and below ground - should be preserved to sustain developmental programs in favourable conditions as well as to maximize survival in response to environmental fluctuations. Decades of research revealed that maintenance of plant stem cells is controlled by a highly conserved network, which includes Homeo-Domain transcription factors and other regulatory proteins (i.e., ligands and receptors), that keeps the balance between cell proliferation and cell differentiation. Among others, the signalling protein CLAVATA3 (CLV3) arose early in the evolution of land plants as it first appeared in Bryophytes, where it promoted the transition from 2D to 3D apical growth. Additional studies indicated that CLV3 proteins also regulate the activity of apical meristems in several angiosperms and determine the architecture of reproductive structures in major crops such as tomato and maize. Despite the wealth of information on the function of CLV3 gained from comparative studies across the green lineage, less is known about the processing of non-functional precursors that leads to the formation of mature short peptides that are secreted to the extracellular space. We are currently investigating the conservation and diversification of those mechanisms underlying the maturation of CLV3 prepropeptide by using different systems – from simple model organisms to agronomically important plants under study in our group. Moreover, we are testing whether the manipulation of these mobile signaling molecules in different angiosperms has an effect on developmental plasticity - a key feature that modulates plant adaptation to abiotic stresses.