Thursday, 17 December 2015

Evolution trail goes live at CUBG





As an impact activity associated with my BBSRC grant 'PIN proteins and architectural diversification in plants' (BB/L00224811), I have worked with Dr Alison Murray (CUBG) and Prof Beverley Glover (CUBG and Plant Sciences Department, Cambridge University) to establish an evolution trail in the Cambridge University Botanic Garden.
The trail currently comprises a selection of plants chosen to represent key steps in plant evolution mapped out in the Garden with a handout to be used by undergraduates taking the 'evolution and behaviour' module that can be signed out from the Brookside entrance.
The trail handout can be downloaded here.
New interpretation boards to showcase the relevance of plants in the 'life before flowers' greenhouse have been designed and will be produced in 2016.
The trail conveys ideas about how plant life has changed over geological timescales from the time that tiny bryophyte-like plants first started to colonise land, through the establishment of the earliest vascular plant shooting systems to the radiation of today's dominant flowering plant flora.
The conquest of land by plants cooled the earth's climate, established the first soils, and provided the food and shelter that allowed animals to colonise land.
Recurring themes of plant interrelationships, plant adaptation to new environments and plants shaping their environment have great relevance to future challenges to humanity in the face of rapid population growth and climate change.


Tuesday, 17 November 2015

Congratulations to Jeremy Solly!

Jeremy had his PhD viva on the 6th of November in Cambridge, and has passed with minor corrections.

His work aimed to determine how growth dynamics contribute to overall plant shape in the liverwort Marchantia polymorpha. He has used  live-imaging, growth analysis, and predictive computational modelling in combination with surgical, pharmacological and genetic manipulations.

His work suggests a model of growth whereby the apical notches regulate shape by setting regional growth rate differences across the thallus, and we are hoping to publish the results soon!

Jeremy has now embarked on a third degree to train as a medical doctor.

Tuesday, 13 October 2015

Sainsbury funded 4-year PhD studentship available





The evolution of plant body plans
The conquest of land by plants over 450 million years ago was one of the most significant events in our planet's history, and was underpinned by a series of key innovations in plant architecture during evolution1.
Our group aims to identify the developmental and genetic basis of two such innovations, three dimensional shoot growth and branching2,3, in a range of model systems representing different stages of plant evolution.
Our recently published work reports mutants with disrupted branching patterns in a moss3-6 and ongoing work has identified mutations that disrupt 3D growth.
Your project will build on these advances to identify molecular determinants of body plan in early diverging land plant lineages.
For further information please see the Harrison lab web page (http://www.bristol.ac.uk/biology/people/jill-j-harrison/overview.html) or contact Dr Harrison directly to discuss your ideas (jill.harrison@bristol.ac.uk).
After discussion, applicants should be prepared to supply a 2-page research proposal, a CV and an academic transcript including the names of three referees. 
The deadline is January 20th 2016.
International students are welcome to apply. 
Further information:
Further Reading:
[1] Pires and Dolan (2012). Morphological evolution in land plants: new designs with old genes. Phil. Trans. R. Soc. 367: 508-518.
[2] Olsen et al 2015 DEK1; missing piece in puzzle of plant development Trends in Plant Science 20: 70-71.
[3] Harrison CJ. 2015. Shooting through time: new insights from transcriptomic data. Trends in Plant Science. DOI:10.1016/j.tplants.2015.06.003.
[4] Coudert YN, Palubicki W, Ljung K, Leyser O, and Harrison CJ. Three ancient hormone pathways regulate shoot branching in a moss. eLife 4 e06808.
[5] Bennett et al. (2014a). Plasma membrane targeted PIN proteins regulate shoot development in a moss. Current Biology 24: 1-10.
[6] Bennett et al. (2014b). Paralogous radiations of PIN proteins with multiple origins of non-canonical PIN structure. Molecular Biology and Evolution (doi:molbev.msu147).

Monday, 28 September 2015

IntoBiology: from the cell to the planet in 90 seconds

www.IntoBiology.org.uk is developing resources and opportunities to expose teenagers interested in biology to the potential of plant science.

Watch their short video to see how plants can inspire you too!

https://youtu.be/uogEnZndTrg

Friday, 31 July 2015

Monday, 20 July 2015

Goodbye Cambridge...... Hello Bristol!

Goodbye Cambridge......

Hello Bristol!

Our new lab is now set up in Bristol- re-posting Yoan’s nice photos of the great research environment.

Tuesday, 7 July 2015

Graduate news: travel awards for Jeremy Solly.


Congratulations to Jeremy Solly who has been awarded travel funding from the SEB, the Genetics Society and the Cambridge Philosophical Society.
The funding will allow him to present his work at this year’s FASEB ‘Mechanisms in Plant Development meeting’ in Vermont.
Jeremy is writing up his PhD and we hope to get feedback on paper plans from the great poster sessions!

Monday, 29 June 2015

New e-mail addresses

Will be jill.harrison@bristol.ac.uk for Dr Harrison and Yoan.Coudert@inria.fr for Dr Yoan Coudert from 13th July......

Friday, 26 June 2015

Shooting through time review out

Margaret Frank and Mike Scanlon have a paper out in New Phytologist comparing the transcriptomes of meristems in three different vascular plants.

The 'Shooting through time' article is a TIPS commentary on the paper, discussing the results in the context of vascular plant evolution.

Here's a link:
http://www.sciencedirect.com/science/article/pii/S1360138515001491

Tuesday, 23 June 2015

Yoan Coudert awarded CNRS ATIP AVENIR fellowship.


Congratulations to Dr Yoan Coudert, who has been awarded a fellowship to start his own group at the Institute of Systematics, Evolution and Biodiversity in the Natural History Museum, Paris.
Yoan’s work will build on his postdoctoral work on the mechanistic basis of branching in Physcomitrella (Coudert et al. 2015) to test the hypothesis that the evolution of branching forms in mosses was underpinned by changes in hormonal cue synthesis, transport and sensitivity. 
He will use a multi-disciplinary approach combining character evolution reconstruction, computational modelling and developmental genetics to identify the molecular mechanisms underpinning key architectural transitions.

Wednesday, 29 April 2015

Blog on our work posted on the Node: http://thenode.biologists.com/


Towards a mechanistic understanding of branching innovations in plant evolution.
Jill Harrison and Yoan Coudert.
The conquest of land by plants was one of the most significant events in our planet's history, and was underpinned by a series of innovations in plant architecture. Amongst these, the innovation of branching stands out in allowing plants to colonize new volumes of space in the subaerial environment.
Unlike most plants, living bryophyte representatives of the earliest land plants have a biphasic life cycle with multicellular forms in both the haploid (gametophyte) and diploid (sporophyte) life cycle stages. The dominant photosynthetic phase of the life cycle is the gametophyte, and the sporophyte typically comprises a single ephemeral stem capped in a spore-bearing reproductive structure1.
Sporophytic branching forms are thought to have evolved once, contributing to the radiation of our dominant vascular plant flora (c. 260,000 species). In contrast, distinct gametophytic branching forms have evolved in each bryophyte lineage (c. 16,000 species)2.
Mosses are the most speciose bryophyte lineage (c. 10,000)2,3. Although all mosses are relatively small, having leaves that are a single cell thick, their branching habits are diverse and contribute to their ecology4 (Figure 1).
http://thenode.biologists.com/wp-content/uploads/2015/04/Harrison-Fig.1.png
Figure 1: The diversity of branching forms in mosses. (A-E) Photographs of herbarium specimens of (A) Braithwaitea sulcata, (B) Hypopterygium arbuscula, (C) Cyatophorum bulbosum, (D) Ancistroides genuflexa and (E) Hymenodontopsis stresemannii showing variation in the vertical and radial distribution of lateral branches on the leafy gametophyte. The distribution of the slender leafless sporophytic stems also varies between species. In the species with erect gametophytic forms (A-C), sporophytes are preferentially localised at the top of the shoot, whereas in a species with a pendant form (D), the sporophytes are dispersed. (E) has sporophytes with a lateral and basal position. Dr Yoan Coudert is collaborating with colleagues at the Royal Botanic Garden, Edinburgh and the Natural History Museum in London to characterise evolutionary trajectories between these and other forms using a character mapping approach. Photos by Dr Yoan Coudert, with thanks to NHM for access to specimens.
There is also an interplay between the gametophytic branching habit and the arrangement of sporophytes on the stem, such that some forms have a single sporophyte at the tip, some forms have a cluster of sporophytes towards the top of the shoot, and others have sporophytes that are dispersed over the plant.
The functional basis and significance of these differences in architecture is not yet known.
Our recent work on the basis of branching patterns in the model moss, Physcomitrella patens, provides a starting point to identify the genetic mechanisms that underpinned the radiation of branching forms in mosses5,6.
As there were no previous reports showing how branches arise in Physcomitrella, we started the project by characterising initiation. Using SEM and histology, we found that branches arise spontaneously from the epidermis with a patterned distribution6.
Data from flowering plants7, other mosses8, other labs9 and other unpublished projects in our lab led us to believe that a hormonal interplay between auxin, cytokinin and strigolactone could contribute to branching patterns.
We used a combination of computational modelling, genetics and pharmacology to show that the integrated action of these three plant hormones determines the distribution of branches up the gametophytic shoot6.
By varying the scope of contributions of each of hormone, we now aim to reproduce the diversity of branching forms in mosses in silico, and will use modelling to generate predictions that allow us to identify the basis of variation between species in future functional work.
The distribution of branches around the shoot is a key component of moss architecture that we have not yet taken into account (Figure 2), and several studies have indicated that the epidermis of Physcomitrella may be the primary site of auxin response5,10,11.
 http://thenode.biologists.com/wp-content/uploads/2015/04/Harrison-Fig.-2.png
Figure 2: Gametophytic branching distributions (A) as represented in Coudert et al. (2015), and (B-D) incorporating radial position. (A) Leaves were removed in a numbered series from gametophytic shoots, and if a branch was revealed, the position was recorded with dark green shading. (B) Movie of a rotating kitchen roll holder with green lines representing leaves ascending the shoot with a 137˚ divergence angle, and blue triangles representing a recorded branch distribution. (C) Photograph showing a cut that allowed us to unravel the kitchen roll holder to see (D) the radial distribution of branched represented in 2D. Photos by Dr Jill Harrison and hands from Dr Yoan Coudert.
As branch initiation is an epidermal phenomenon, we will adapt our 2D modelling approach to analyse 3D branching architectures including radial patterning. We aim to analyse the level and distribution of each plant hormone in relation to the branching distribution with new fluorescent reporter systems in the future.
The work opens the door to mechanistic understanding of the transitions in form that happened during the evolution of branching- one of the defining features of our dominant land plant flora.
Further reading:
1 Langdale & Harrison (2008). 'Developmental changes during the evolution of plant form' in Evolving Pathways: Key Themes in Evolutionary Developmental Biology (ed A. Minelli and G. Fusco) p.299-315.
2 Shaw et al. (2011). Bryophyte diversity and evolution: windows into the early evolution of land plants. American Journal of Botany 98, 353-369.
3 Laenen et al. (2014). Extant diversity of bryophytes emerged from successive post-Mesozoic diversification bursts. Nature Communications 5, doi:doi:10.1038/ncomms6134.
4 La Farge-England (1996). Growth form, branching pattern, and perichaetial position in mosses: cladocarpy and pleurocarpy redefined. The Bryologist 99, 170-186.
5 Bennett et al. (2014). Plasma membrane-targeted PIN proteins drive shoot development in a moss. Current Biology 24, 2776-2785.
6 Coudert et al. (2015). Three ancient hormonal cues co-ordinate shoot branching in a moss. eLIFE, doi:10.7554/eLife.06808.
7 Domagalska & Leyser (2011). Signal integration in the control of shoot branching. Nat Rev Mol Cell Biol 12, 211-221.
8 von Maltzahn (1959) Interaction between kinetin and indoleacetic acid in the control of bud reactivation in Splachnum ampullaceum (L.) Hedw. Nature 183, 60-61.
9 Proust et al. (2011). Strigolactones regulate protonema branching and act as a quorum sensing-like signal in the moss Physcomitrella patens. Development. 138, 1531-1539.
10 Bierfreund et al. (2003). Use of an inducible reporter gene system for the analysis of auxin distribution in the moss Physcomitrella patens. Plant Cell Reports 21, 1143-1152.
11 Jang et al. (2011). RSL genes are sufficient for rhizoid system development in early diverging land plants. Development 138, 2273-2281.

Wednesday, 22 April 2015

Harrison lab moving to Bristol


Dr Jill Harrison has been appointed to a proleptic lectureship in the Life Sciences at the University of Bristol.
The lab will be in a brand new building, housing a mix of expertise that will be exciting in future collaborations with our group. 
As well as a strong core of plant scientists, we are particularly looking forward to working with people doing palaeobiology, evolution, and synthetic biology. 
We will be moving in July, and welcome enquiries from prospective PhD students and post-docs.
Join us in the 'sky lounge' for a coffee!

Wednesday, 25 March 2015

Paper out :-)

Thanks to eLIFE for a super quick turn around on our paper, now out!

http://elifesciences.org/content/early/2015/03/25/eLife.06808

Tuesday, 24 March 2015

Paper accepted: Three ancient hormonal cues regulate shoot development in a moss.

Yoan and I have been working closely with Wojtek Palubicki and Ottoline Leyser at the Sainsbury Laboratory and others to work out what regulates gametophytic branching in mosses.

We have used a combination of developmental, genetic and computational techniques to tackle the problem, and the results will be out soon in eLIFE.

The work shows that although the same hormonal cues regulate flowering plant and moss branching patterns, their mode of action is distinct in each group.

It paves the way for new understanding of patterning mechanisms in plants, and for Yoan's future plans to identify the mechanisms underpinning the diversification of moss architecture.


Chinese new year celebration

Maintaining our lab tradition of a chinese new year celebration with friends, this year at 7 Days to give Xiao a break from cooking!




Tuesday, 17 February 2015

What is the point of plants?

Check out Prof Jane langdale on Radio 4's The Infinite Monkey Cage this week: http://www.bbc.co.uk/programmes/b052hptj. 
The discussion covers our shared common ancestry with fungi, the emergence of plant life,  how photosynthesis splits water to release oxygen and capture carbon dioxide and how to lose your academic credibility!