Biological Sciences has three lectureships/senior lectureships open, and we are hoping to recruit to the general area of plant science to complement existing departmental strengths. The advert is online here. We are also looking to support early career researchers in Leverhulme fellowship applications in the area of plant science related to agriculture. Full info on the Bristol Centre for Agricultural Innovation website here NB tight turn around for 8th January!
Wednesday, 16 December 2020
Monday, 30 November 2020
The gene regulatory logic of plant stem cell function
Plant shape is patterned by the activity of stem cells in the growing shoot tips and is a major determinant of plant productivity and yield. The size of the stem cell pool in Arabidopsis shoot tips is kept constant as plants grow by the activity of a small genetic circuit comprising small peptides, their receptors which act as kinases, and a downstream transcription factor. The CLV3 peptide acts via the CLV1 receptor to suppress the transcription of the WUSCHEL transcription factor, and WUSCHEL then moves to the CLV3 expression domain, promoting expression to generate a feedback loop to maintain the size of the stem cell pool. The hormonal environment of cells in the shoot apex is also important in regulating stem cell activity, and the CLV/WUS feedback loop intercepts auxin and cytokinin signalling.
The CLV/WUS pathway operates in a similar way in many flowering plants. However, the WOX gene family has undergone extensive duplications and losses in the plant tree of life, and CLV is only present in land plants. These findings raise questions about the fundamental requirements of land plant stem cell function.
This project aims to interrogate the fundamental requirements for land plant stem cell function by testing whether CLV acts via WOX genes in Physcomitrium. The project will involve generation of loss-and gain-of function mutants and reporter lines and phenotypic analysis to build a model of WOX function.
Combined with ongoing work in my lab on hormonal interactions with CLV, the findings will enable us to deduce the regulatory logic of Physcomitrium stem cell function. Comparison with findings from Arabidopsis will reveal generalities in the regulatory logic of land plant stem cell function, with broad potential significance in plant science.
Applications: Please see info here, or get in touch with me if you want further info.
Wednesday, 14 October 2020
Supervised by Dr Jill Harrison and Dr Tom Gorochowski
Plant shape is a primary determinant of plant productivity and yield, affecting light interception and photosynthesis. As plant cells are bound by a cell wall and cannot move, shape arises as an outcome of the plane new divisions in stem cells at the shoot tips, cell fate determination and subsequent cell growth.
Flowering plant models such as Arabidopsis have complex tissue organizations that can mask cell division plane defects. There are many genes per gene family, which can make it hard to identify mutants. For these reasons, few genetic regulators of stem cell division plane orientation have been discovered.
In contrast to flowering plants, mosses have simple tissue organizations with a single stem cell at each growing point, and there are few genes per gene family. My lab has determined that the CLAVATA receptor-like kinase sets the plane of moss stem cell divisions [1, 2]. Although mosses are distantly related to flowering plants, our findings were transferable to Arabidopsis, and we are building a pipeline for knowledge transfer to improve yield by manipulating CLAVATA function in wheat .
This project feeds in at the fundamental end of the pipeline, aiming to harness the advantages of the moss model to reveal downstream effectors of CLAVATA function that determine the plane of stem cell divisions at plants’ growing points.
To this end the project will:
1. Generate mutants of a candidate target and analyse mutant phenotypes
2. Identify downstream targets of CLAVATA by RNAseq and bioinformatic analysis
3. Analyse gene regulatory network architecture using computational approaches
4. Identify novel cell division plane regulators using a suppressor screen.
By combining computational and wet lab approaches, the project will provide training at the cutting edge of the plant development field. It will benefit from further formal teaching and internships included in the SWBioDTP programme. The skills and techniques the student will learn will be broadly applicable in the academic biology and biotech sectors and widely transferable amongst areas such as science policy, publishing and computing.
 Harrison et al. 2009. Local cues and asymmetric cell divisions underpin body plan transitions in the moss Physcomitrella patens. Current Biology 19: 1-11.
 Whitewoods et al. 2018. CLAVATA was a genetic novelty for the morphological innovation of 3D growth in land plants. Current Biology 28: 2365-2376.
 Fletcher 2018. The CLV-WUS stem cell signaling pathway: a roadmap to crop yield optimization. Plants 7: 87.
UK and EU citizens are eligible to apply. The closing date is 7th December 2020, you are welcome to get in touch to discuss the project at firstname.lastname@example.org.
Monday, 14 September 2020
Really proud of my postdoc Vicky and PhD student Zoe for getting this review finished off during our lockdown... We hope to see use of lycophytes as evo-devo models expanding further, as many great questions about their biology and evolution are still open.