BBSRC SWBioDTP studentship open to work on Marchantia plant shape determination.

Supervisors: Dr Jill Harrison and Dr Martin Homer.

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 shape diversification. We can therefore study 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, we previously used a combination of live imaging, statistical model fitting, computational modelling and molecular biology to discover mechanisms regulating shape in the liverwort Marchantia polymorpha (Solly et al. (2017): Current Biology).

We found that Marchantia undergoes a stereotypical sequence of shape transitions during development. The overall shape depends on regional growth rate differences that are specified by the growing apical notches. Computational modelling showed that a diffusible, growth-promoting cue produced in the notches is likely to pattern these regional growth rate differences, and pharmacological experiments suggested that the plant hormone auxin equates to this growth-promoting cue.

New models suggest a role for differential oriented growth (anisotropy) in Marchantia shape determination. Anisotropy emerges as an outcome of underlying tissue polarities, and directional auxin transport may have a role.

Your project will build on the work above to determine how auxin contributes to plant shape determination in Marchantia.

It will:

1. Predict the effects of different tissue polarities on Marchantia shape by modelling

2. Analyse the auxin distribution in Marchantia and compare it to distributions predicted by modelling

3. Disrupt auxin biosynthesis, directional transport, conjugation and decay and test the effect on growth and shape

4. Use live-imaging, image segmentation and quantitative growth analyses to discover how growth and shape change in plants with different auxin biology.

Training:

By combining computational and wet lab approaches, your project work will provide training at the cutting edge of the plant evolution and development fields. You will benefit from further formal teaching and internships included in the SWBioDTP programme. The skills and techniques you learn will be broadly applicable in the academic biology and biotech sectors and widely transferable amongst areas such as science policy, publishing and computing.

Reading:

Harrison (2017). Development and genetics in the evolution of plant body plans. Philosophical Transactions of the Royal Society B 372: 20150490.

Hong and Roeder (2017). Plant development: differential growth rates in distinct zones shape and ancient plant form. Current Biology 27: R19-21.

Solly et al. (2017). Regional growth rate differences specified by apical notch activities regulate liverwort thallus shape. Current Biology 27: 16-26.

Whitewoods and Coen (2017). Growth and development of three-dimensional plant form. Current Biology 27: R910-918.

Further information:

The deadline for applications is 4th December 2017. Please contact Dr Jill Harrison (jill.harrison@bristol.ac.uk) for informal discussions about the project. Further information about project supervisors’ work can be found on Jill Harrison and Martin Homers’ home pages. Further information about the SWBioDTP and application procedures is listed on the SWBioDTP web pages.