PhD opportunity: Mechanisms for shape determination in Marchantia polymorpha

Project description:

Plant shapes range from tiny string or mat-like forms to massive multilayered upright forms with complex organ systems such as shoots, roots and leaves. Despite these wide differences in shape, many plant gene families are very ancient, predating diversification. We can therefore study the mechanisms for shape determination in simple plants such as liverworts and use the knowledge gained to understand plant shape determination in general.

To this end, my lab has used a combination of live imaging, statistical model fitting, computational modeling and molecular biology to discover mechanisms regulating shape in the liverwort Marchantia polymorpha.

We found that Marchantia undergoes a stereotypical sequence of shape transitions during development. Key aspects of global shape depend on regional growth rate differences specified by the co-ordinated activities of the growing apical notches. Using modelling we show that a diffusible growth promoting morphogen produced at each notch cannot fully account for the observed growth rate distributions. Instead, we hypothesize that the notches may pre-pattern the growth rate distribution. Your project will build on our prior work to validate the above ‘notch pre-patterns growth’ model of shape determination to discover the molecular identities of factors contributing to growth.

The project aim is to test the hypothesis that the plant hormone auxin corresponds to the notional morphogen in our ‘notch pre-patterns growth’ model of shape determination.

The project will involve:

1.          Analysis of the auxin distribution in Marchantia polymorpha

2.          Up and down regulation of auxin biosynthesis, transport, conjugation and decay

3.          Analysis of mutant shapes using live-imaging

4.          Comparison between experimental manipulations and model manipulations.

Training:

By combining computational and wet lab approaches, the project will provide training at the cutting edge of the plant evolution and development fields. The techniques that you learn will be broadly applicable in the academic biology and biotech sectors. The skills that you learn will be widely transferable to other areas such as science policy, publishing and computing.

Further information:

Please contact Dr Jill Harrison (jill.harrison@bristol.ac.uk) for further information about the project and application procedures.