Paper accepted and paper out

Jeremy Solly, Nik Cunniffe and I have written up part of Jeremy's PhD research on mechanisms for shape determination in the liverwort Marchantia polymorpha.

We have used a combination of developmental, statistical, computational and pharmacological approaches to address the problem, and the results will be published soon in Current Biology.

Results from Ross Dennis's work in my lab and Paolo Bombelli's work in Chris Howe's lab in Cambridge are now published in Royal Society Open Science.

In it we show that mosses can be grown in waste tip boxes to convert them into fuel cells with sufficient output to power a small radio or environmental sensor, and bacterial contaminants that grow happily with the moss boost the power output.

Congrats to Jeremy and Ross!

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.

NERC PhD studentship available: Body plan evolution in plants

Supervisors: Dr Jill Harrison, University of Bristol (main supervisor); Dr Tom Williams, University of Bristol; Dr Gary Barker, University of Bristol
 

A range of multicellular plant forms.

Plants and animals both evolved complex multicellular forms from a unicellular ancestor shared around 1.6 billion years ago. Whilst animal body plans are determined by cell shape, adhesion and movement during embryo development, plant cells cannot move and body plans are instead determined by cell division and growth throughout development [1]. Plant body plans range from tiny string or mat-like forms that grow across a surface to massive multilayered upright forms with complex organ systems such as shoots, roots and leaves. Despite these wide differences, many of the gene families involved are very ancient, predating the radiation of plant body plans. This raises questions about the nature of genetic change driving body plan innovations.

For the first time, new model systems across the plant tree of life have opened the possibility of identifying the genes involved in plant evolution [2]. To date this has been done by transferring knowledge of flowering plant development to other species on a gene-by-gene basis. However, this approach is biased and places undue weight on the knowledge that we already have.

This project aims to use novel bioinformatic approaches [3,4] to unlock plant body plan evolution by wholesale, genome-wide identification of genes associated with specific innovations.

The project will involve:

1.     Plant collection and growth

2.     DNA extraction, genome sequencing and genome annotation

3.     Data mining and bioinformatic analysis

4.     Targeted analyses of gene function.

Whilst animal body plans radiated in Cambrian seas, plant body plans radiated on land during the Devonian era. Results from your project will pinpoint the genetic changes that generated the terrestrial biosphere.

By combining distinct bioinformatic and wet lab skill sets, the project will provide training at the cutting edge of the plant evo-devo field. The techniques you learn will be broadly applicable in academic biology and biotech sectors. The skills you learn will be widely transferable to other areas such as science policy, publishing, computing and finance.

Application: The scholarship is open to UK and EU applicants, and the deadline is 6 January 2017. The application form and guidelines are available here at the address below:

http://www.bristol.ac.uk/study/postgraduate/apply/

Further information:

Please see http://www.bristol.ac.uk/biology/people/jill-j-harrison/index.html or e-mail Jill Harrison (jill.harrison@bristol.ac.uk) with any questions about the project or for access to the papers below.

Further reading:

[1] Meyerowitz EM (2002). Plants compared to animals: the broadest comparative study of development. Science 295: 1482-148.

[2] Harrison CJ (2016). Developmental and genetic changes in the evolution of land plant body plans. Accepted for publication in Phil Trans R Soc B.

[3] Szöllősi GJ et al. (2013). Efficient exploration of the space of reconciled gene trees. Syst Biol 62: 901-912.

[4] Williams et al. (2015) New substitution models for rooting phylogenetic trees. Phil Trans R Soc B 20140336.

Two papers accepted

Jill Harrison has had a review paper on auxin transport in the evolution of branching forms accepted for publication as a Tansley Insight in New Phytologist.

In a second paper, Paolo Bombelli, Ross Dennis and co-author use Physcomitrella patens in a simple fuel cell with sufficient output to power a commercial radio receiver or LCD desktop weather station. The results will be published in Royal Society Open Science.