Place: Room 621/622, GP South (Building 78)
Time: Thursday 22nd November, 10:30 morning Tea, 11:00am seminar

Title: "Generation Computational Modelling for Studying Signalling Mechanisms behind Autoregulation of Nodulation"

Speaker: Liqi Han, PhD Candidate ARC Centre for Complex Systems, Mathematics, UQ.
Supervisors: Dr. Jim Hanan & Prof. Peter Gresshoff

Signalling mechanisms play a vital role in plant development and function, controlling processes such as germination, root growth, flowering, branching, and nodulation. However, these dynamic processes are so complex that details about them are still largely unknown. Endogenous signals in particular, such as those based on plant hormones and peptides, are difficult to observe and remain a critical challenge for botanical research. As an addition to conventional biological approaches, new approaches and techniques of computational modelling must be developed to investigate the complexities of signalling occurring at and between different levels in plant systems. For this project, nodulation of legumes has been chosen as the target system.

Nodulation is a developmental process resulting from the symbiosis of legume plants with a group of bacteria known as rhizobia. The rhizobia colonise legume roots to house themselves and provide fixed nitrogen for the host plants. Since excessive nodulation can cause overconsumption of resources, a balance of nodulation is maintained by a legume regulatory system called autoregulation of nodulation (AON). The general framework of short- and long-distance control of AON has been established experimentally, but detailed signalling mechanisms still remain unclear. The aim is to develop new methods and techniques of computational modelling to help gain a better understanding of the signalling
mechanisms involved.

To explore the qualitative and quantitative attributes of AON signalling, computational models for hypotheses testing and prediction at multiple scales will be built. The focus of this project will be developing functional-structural plant models (FSPM) of wildtype soybean and its supernodulation mutant for investigation of AON signalling in a growing structure. In these FSPM models, hypothesised signalling mechanisms will be integrated to regulate plant architectural development. An iterative process of hypotheses testing-modification-testing will be conducted until satisfactory simulation results are obtained. Local signalling events occurring with nodule formation and cellular-level signal transduction will be studied by computational modelling as well. The methods and techniques developed in this project are also expected to be helpful for more general studies involving plant signalling mechanisms.

Dr. Ariel Liebman  
Research Fellow
ARC Centre for Complex Systems
School of ITEE, University of Queensland
email: a.liebman@uq.edu.au
tel: +61-7-3365-1623
mobile: +61-(0)414-226-336
room: 78-414, GP South, St Lucia Campus
web: www.accs.edu.au