I am recruiting to an open 3 year post-doctoral position on the origin of apical growth in plants. The project is collaborative and will involve:

1. Moss mutagenesis and a screen for mutants with defective sporangia
2. Establishment of a method for Selaginella transgenesis using extensive preliminary data to guide experiments
   
3. Reverse genetic analysis of Selaginella CLAVATA gene function.

There is more information about the project and how to apply here, and please do get in touch with me on Jill.Harrison@bristol.ac.uk if you would like to discuss the role.

Would you like to identify genes enabling the origin of apical growth?

 Very excited to be able to advertise a post-doc opening to join a HFSP project on the origin of apical growth in vascular plants. The project focusses on lycophytes, and ties together analyses of fossil and living lycophyte morphology with transcriptomic and developmental and genetic studies. It will involve collaboration with partners in Edinburgh (Sandy Hetherington), Kyoto (Rieko Fujinami), and Ghent (Tom Beeckman), and some exchange between labs. Work in my lab will identify genes initiating sporangium development and test the role of candidate regulators of lycophyte apical growth. The closing date is 6th March 2024, and I’m happy to take any questions about it by e-mail. There is more information on this link.

Hiring post-docs for HFSP project on the origin of apical growth

Very excited that Sandy Hetherington in Edinburgh is advertising the first of four post-doctoral positions on our HFSP funded project on the origin of apical growth. More information and applications here, NB closing date 30th of October 2023.

HFSP grant on the origin of apical growth

I am super chuffed to have been awarded a Human Frontiers grant with Tom Beeckman (VIB, Ghent), Rieko Fujinami (Kyoto University of Education) and Sandy Hetherington (Edinburgh University) to unmask key innovations enabling the origin of apical growth in vascular plants. 

Weighted towards the ancient lycophyte group, our work aims to use fossils and phylogeny to identify the ancestral apex structure of vascular plants and to establish a lycophyte genetic model for comparative analyses of apical function in vascular plants.

Keep an eye out for four future post-doc positions to join us and work on this exciting project, and please get in touch if you are interested!

@HFSP, @BristolBioSci, @beeckman_tom, @fujinami_rieko, @Sandy_Heth, @InstMolPlantSci

Lycophyte (Selaginella kraussiana) shoot apices
viewed by SEM

Congratulations to Vicky Spencer on publishing her work on the evolution of branching!

My team have a new paper out today in development on the evolution of branching, showing that bifurcation in the lycophyte Selaginella kraussiana is regulated by auxin transport and that PIN-mediated auxin transport is an ancestral regulator of branching within the vascular plants. Really proud of my post-doc Vicky Spencer who started the project in 2019 and did the work through the pandemic, and one of our undergraduates Lucy Spencer who helped out in her free time. The results from their careful surgical experiments are lush, and you can read about the work here @Dev_journal! Thanks @LeverhulmeTrust for funding our project.

Scanning electron micrograph of a Selaginella kraussiana shoot tip.

Paper on RPK2 function in Physcomitrella filaments BioRXived

Neil Ashton and David Cove identified roles for auxin in promoting and cytokinin in suppressing plant spread across a substrate in Physcomitrella through pharmacological experiments and mutant screens the 1970s [1]. Both hormones affect the activity of the stem cells at the tip of protonemal filaments, with auxin biasing tip cell identity towards foraging caulonemal fate and cytokinin biasing identity towards photosynthetic chloronemal fate [2]. Although the tip cells are the site of growth responses, Thelander et al. (2019) showed that auxin signalling is strongest away from the tip cells, posing a conundrum about how tip cells function [3]. Zoe Nemec Venza’s PhD with me has investigated roles for a key regulator of Arabidopsis stem cell fate in Physcomitrella and addressed this question [4]. She has found that components of the CLAVATA receptor-like kinase pathway are active in tip cells, regulating auxin homeostasis and auxin transporter expression to determine tip cell fate and plant spread. We have BioRXiVed a manuscript presenting her findings here, and we would very much welcome your feedback prior to publication. 

[1] Ashton et al. (1979). Analysis of gametophytic development in the moss, Physcomitrella patens, using auxin and cytokinin resistant mutants. Planta 144: 427-435. 

[2] Jang and Dolan (2011). Auxin promotes the transition from chloronema to caulonema in moss protonema by positively regulating PpRSL1and PpRSL2 in Physcomitrella patens. New Phytologist 192: 319-327. 

[3] Thelander et al. (2019). Minimal auxin sensing levels in vegetative moss stem cells revealed by a ratiometric reporter. New Phytologist 224: 775-788. 

[4] Nemec Venza et al. (2021). PpRPK2 modulates auxin homeostasis and transport to specify stem cell identity and plant shape in the moss Physcomitrella. https://doi.org/10.1101/2021.06.24.449551