Tuesday 29 October 2019

Fully funded BBSRC SWBio CASE PhD Studentship: Intercepting CLAVATA receptor-like kinase function to engineer ear size in wheat


Summary
Ensuring continuous global food security will be a major challenge of the 21st century, and wheat contributes approximately 20% of the total calories consumed by humans (FAO, 2017). In cereals like wheat, inflorescence (ear) size determines the number of flowers (florets) and grains produced, and this aspect of plant architecture is regulated by the activity of stem cells in the growing shoot tips. The CLAVATA peptide/ receptor-like kinase signalling pathway maintains the size of the stem cell pool during plant development, and mutants in maize and tomato have increased yields, arising due to an increase in size of the stem cell pool.
This project aims to intercept wheat CLAVATA signalling to engineer ears with more fertile grain sites and increase yield.
The project will involve:
(1) Identification of wheat CLAVATA pathway components
(2) Expression analyses of wheat CLAVATA pathway components
(3) Generation phenotypic analysis of wheat CLAVATA pathway mutants.
Dr Harrison’s group has recently published gene trees for CLAVATA pathway components from a range of land plants (Whitewoods et al. (2018)), and she has experience of analysing gene expression patterns and function in a wide range of plant species. Professor Edwards and colleagues from the Bristol Centre for Agricultural Innovation have extensive experience with wheat having sequenced the genome (Brenchley et al. (2012)), identified many mutants from the exome sequenced Cadenza TILLING mutant population (Krasileva et al. (2017)) and established engineering procedures using CRISPR/Cas9. The CASE partnership with RAGT seeds will bring an opportunity for the student to directly experience wheat breeding and exchange knowledges and finding with wheat growers.
Training
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.
Reading
Brenchley et al. (2012). Analysis of the bread wheat genome using whole-genome shotgun sequencing. Nature 491: 705-710.
Krasileva et al. (2017). Uncovering hidden variation in polyploid wheat. PNAS 114: E913-E921.
Whitewoods et al. (2018). CLAVATA was a genetic novelty for the morphological innovation of 3D growth in land plants. Current Biology 28: 2365-2376.   
Application procedure
Informal enquiries to Jill.Harrison@bristol.ac.uk
Eligibility: UK residents plus EU applicants with restrictions
Closing date: Monday 2nd December 2019
Shortlisting: 8th January 2020
Interviews: 28th January 2020

Fully funded BBSRC SWBio PhD studentship: Mechanisms for cell division plane orientation in plants


Summary
Plant shape is a primary determinant of productivity and yield because it affects light interception and photosynthesis. As plant cells are bound by a cell wall and cannot move, shape arises as an outcome of the plane of new cell divisions, and subsequent cell growth. Flowering plant models such as Arabidopsis have complex tissue organisations that can mask cell division plane defects. There are also many genes per gene family, which can make it hard to identify mutants. For these reasons, few genetic regulators of cell division plane orientation have been discovered.
In contrast to flowering plants, mosses have simple tissue organisations and there are few genes per gene family. I established a moss model to study plant cell division plane orientation [1], and recently determined that the CLAVATA receptor-like kinase sets the plane of cell divisions [2, 3]. Although mosses are distantly related to flowering plants, our findings were transferable to Arabidopsis, and we are now manipulating CLAVATA function in wheat to improve productivity [4]. Harnessing the benefits of the moss model, this project aims to discover how CLAVATA determines the plane of cell divisions in plants to affect their overall shape and productivity.
To determine how CLAVATA orients division planes in moss the project will:
1. Identify downstream targets of CLAVATA by RNAseq and bioinformatic analysis
2.  Generate mutants of a candidate target and analyse mutant phenotypes
3. Analyse gene regulatory network architecture using computational approaches
4.  Identify novel cell division plane regulators using a suppressor screen.
Training
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.
Reading
[1] Harrison et al. 2009. Local cues and asymmetric cell divisions underpin body plan transitions in the moss Physcomitrella patens. Current Biology 19: 1-11.
[2] Whitewoods et al. 2018. CLAVATA was a genetic novelty for the morphological innovation of 3D growth in land plants. Current Biology 28: 2365-2376.
[3] Bergmann 2018. Taking development to three dimensions. Developmental Cell 17: 678-679.
[4] Fletcher 2018. The CLV-WUS stem cell signaling pathway: a roadmap to crop yield optimization. Plants 7: 87.
Application procedure
Informal enquiries to Jill.Harrison@bristol.ac.uk
Eligibility: UK residents plus EU applicants with restrictions
Closing date: Monday 2nd December 2019
Shortlisting: 8th January 2020
Interviews: 28th January 2020

Tuesday 15 October 2019

Paper on moss leaf development out

Ross Dennis, Chris Whitewoods and I have a paper looking at how to compare leaf phenotypes between Physcomitrella plants out online today with the Journal of Bryology.
You can download a copy here (First 50 only!).