We study the molecular mechanisms underlying the formation and function of arbuscular mycorrhizal (AM) symbiosis in rice and maize.
In order to maximise mycorrhizal benefits in crops we are studying the signaling mechanisms that enable the establishment of AM symbiosis and effective symbiotic mineral acquisition. We also aim to develop our knowledge of these associations to optimize the incorporation of the AM symbiosis into sustainable agricultural practices.
We will continue to identify and functionally characterise plant genetic determinants that impact the plant’s reprogramming for symbiosis and therefore the effectiveness of AM symbioses in rice and other cropping systems.
We would like to understand the regulation and dynamics of the symbiotic phosphate and nitrogen uptake pathway under laboratory and field conditions. This will help us exploit the symbiosis and develop cereal cultivars better adapted to low-input rice agro-ecosystems. Our approaches combine molecular genetics and advanced live imaging, covering the scales from field to cells and back.
Establishment of AM symbioses relies on the continuous orchestration of signals to achieve recognition and coordination of the interacting organisms. We have identified genetic determinants of the rhizosphere dialogue from rice and maize. Their functional characterization will shed light on the communicative signal exchange, “sending” and “receiving”, that impacts on the plant’s reprogramming for symbiosis and therefore on the effectiveness of AM symbioses in rice and other cropping systems.
Symbiotic phosphate acquisition
Phosphate (Pi) acquisition of crops via AM symbioses gains increasing importance due to limited Pi reserves and demand for environmentally sustainable agriculture. We found that 70% of the Pi acquired by aerobically- grown rice is delivered via the symbiotic route. We would like to understand the functioning and regulation of this pathway under laboratory and field conditions to exploit the symbiosis and develop rice cultivars better adapted to low-input rice agro-ecosystems.
Arbuscules, the heart of the symbiosis
‘Arbuscules’ are fascinating fungal feeding structures, produced inside root cortical cells by arbuscular mycorrhizal fungi. Arbuscules are built by consecutive dichotomous hyphal branching, ultimately adopting a complex tree-like shape at microscopic scale. As the arbuscule develops, the hostplant cell undergoes fundamental architectural adaptations to accommodate the intracellularly expanding fungus.
For instance, the plant cell dramatically increases membrane biogenesis to envelope the growing hyphal structure in the so-called peri-arbuscular membrane. The hugely enlarged membrane surface area between the two organisms appears ideal for the exchange of signals and nutrients.
Remarkably, despite what seems a considerable metabolic investment, arbuscules collapse after a few days, and host cell architecture is restored to that of a non-colonized cell. Therefore, the life of an arbuscule is marked by the highly dynamic continuum of development and collapse without static intermediate stages. To capture arbuscule formation and turnover in 4D, and at ultrastructural resolution, we combine advanced multiphoton confocal imaging of living mycorrhizal rice roots with high resolution electron microscopy.
About the group leader
Uta Paszkowski is Professor of Plant Molecular Genetics at the Department of Plant Sciences of the University of Cambridge and leads the Cereal Symbiosis Group at the Crop Science Centre. She did her undergraduate studies at the University Cologne (Germany) gaining a Master (Diplom) degree in phytopathology at the Max-Planck Institute for Plant Breeding.
Uta received her PhD in Biotechnology at the ETH-Zurich (Switzerland) and conducted two postdocs on molecular genetics of arbuscular mycorrhizal symbiosis at the University Basel (Switzerland) and the Torrey Mesa Research Institute in San Diego (USA).
She started her own research group at the University of Geneva (Switzerland), followed by an Assistant Professorship position at the University Lausanne (Switzerland) before moving to Cambridge University in October 2012 where she now is a full professor.