Water moves through plants following apoplastic and symplastic routes and encounters a series of resistances. The sum of these resistances determines water transport rates, which in turn control water availability to the plant organs, and growth and survival of the plant. Resistances to water flow in roots, shoots and leaves are due to structural factors (transport across cell walls and membranes, xylem embolization) and are finely regulated.

We are interested in the effect of agronomic and environmental factors on shoot water conductivity in woody plants, particularly grapevine. We study how water stress and shoot positioning modify shoot hydraulic conductivity, in relation to hormonal signaling (auxin from the apex, ABA from the root). We perform plant water physiology measurements to assess water potential, gas exchange, sap flow and hydraulic conductivity. Furthermore we work on the role of membrane intrinsic proteins (MIPs) or aquaporins in cellular water transport. To this aim we are characterizing aquaporin genes of V. vinifera L., and their physiological function and expression pattern in grapevine. In addition, we have overexpressed the aquaporin VvPIP2;4N in grapevines to demonstrate its functions in watered and in droughted conditions.

Strigolactones are a family of carotenoid-derived plant metabolites with a multitude of functions, both in the plant and in the biotic environment surrounding it. Structurally they all share an ABC-ring system connected via an enol-ether bridge to a butenolide ring named D. Exuded in soil, they stimulate seed germination of root-parasitic weeds; however their most prominent and recently discovered role is as hormones influencing whole-plant morphology and development, especially in response to stress. In the root, they are involved in the accommodation process for symbiotic N-fixing bacteria and mycorrhizal fungi, and they also stimulate hyphal branching in soil. Thus, strigolactones indirectly improve plant mineral nutrition, and because of their influence on plant morphology, they are key resource allocators in response to environmental changes - namely under limited water and nutrient availability. This strongly suggests the possibility that their manipulation, or at least a fine understanding of their biology, would allow to steer their metabolism to improve plant yield in stressful environments.

Our current research interests on the topic include strigolactone perception, role and metabolism under osmotic stress. We are working on the cell biology, molecular and structural details of perception by collaborating with organic chemists, crystallographers, and drug designers. We also aim at understanding what the local and systemic changes of strigolactone levels - that we observe in different organs of plants undergoing osmotic stress - mean for whole-plant hormonal balance (namely, in the cross-talk with abscisic acid). Finally, we are trying to feed our knowledge into crop management practices that will improve plant performances and yield under stress.med D. Exuded in soil, they stimulate seed germination of root-parasitic weeds; however their most prominent and recently discovered role is as hormones influencing whole-plant morphology and development, especially in response to stress. In the root, they are involved in the accommodation process for symbiotic N-fixing bacteria and mycorrhizal fungi, and they also stimulate hyphal branching in soil. Thus, strigolactones indirectly improve plant mineral nutrition, and because of their influence on plant morphology, they are key resource allocators in response to environmental changes - namely under limited water and nutrient availability. This strongly suggests the possibility that their manipulation, or at least a fine understanding of their biology, would allow to steer their metabolism to improve plant yield in stressful environments.