Supervisor
Dr Madelaine Bartlett
Overview:
Plants transition from juvenile to adult vegetative growth phases, and from vegetative growth to flowering. Each of these phases–juvenile, adult, flowering–is characterised by specific anatomical, morphological, and molecular traits (Poethig & Fouracre, 2024). In agriculture, crops are more sensitive to weeds, independent of available resources, before they have transitioned to flowering (Horvath et al., 2023). A microRNA (miR156) regulates the juvenile to adult transition in flowering plants, acting through the SPL transcription factor genes (Poethig & Fouracre, 2024). While SPL mutants and juvenile vs. adult traits are well-characterised in select lineages, including maize (Chuck et al., 2007, 2014; Xiao et al., 2022; Poethig & Fouracre, 2024), this is not the case for many key model organisms or weeds. This project will define the morphological, anatomical, and molecular components of phase change, as well as work on developing advanced tools for genome editing in the grasses. This work will generate a multi-scale atlas of developmental phase change, setting the stage for modulating molecular pathways underlying grass crop yield.
Importance of Research:
This comparative framework will allow us to identify precise, robust morphological and molecular traits of phase change, applicable across grass diversity. The morphological markers will be useful for precise experimentation and field diagnostics, while the molecular traits will be useful for identifying potential targets for yield improvement. The genetic reagents and methods we develop have the potential to be broadly applicable and accelerate grass research.
Project Summary:
The student selected to work on this project will:
- Identify broadly conserved phase change traits by defining morphological juvenile vs. adult traits across grass diversity.
- Knock down SPL genes in blackgrass and barley using established viral-induced gene silencing (VIGS) protocols (Mellado-Sánchez et al, 2020; Patterson et al, 2025).
- Modify an established VIGS platform for viral-induced gene editing (VIGE) and make blackgrass and barley SPL mutants using this method (Weiss et al., 2024).
- Compare the genomic, epigenomic, transcriptomic and morphological traits impacted by SPL disruption across barley, blackgrass, brachypodium, and maize.
What will the successful applicant do?
This project involves an integrative combination of comparative morphology, development, genetics, and genomics. In addition, the project includes methods development in viral induced gene editing. Students will gain experience with a broad range of computational and wet lab techniques, as well as with quantitative phenotyping and genetic analysis in multiple plant systems.
References:
Chuck GS, Brown PJ, Meeley R, Hake S. 2014. Maize SBP-box transcription factors unbranched2 and unbranched3 affect yield traits by regulating the rate of lateral primordia initiation. Proceedings of the National Academy of Sciences of the United States of America 111: 18775–18780. DOI:10.1038/ng2001
Chuck G, Cigan AM, Saeteurn K, Hake S. 2007. The heterochronic maize mutant Corngrass1 results from overexpression of a tandem microRNA. Nature genetics 39: 544–549. DOI:10.1038/ng2001
Horvath DP, Clay SA, Swanton CJ, Anderson JV, Chao WS. 2023. Weed-induced crop yield loss: a new paradigm and new challenges. Trends in plant science 28: 567–582. DOI:10.1016/j.tplants.2022.12.014
Mellado-Sánchez M, McDiarmid F, Cardoso V, Kanyuka K, MacGregor DR. 2020. Virus-Mediated Transient Expression Techniques Enable Gene Function Studies in Black-Grass. Plant physiology 183: 455–459. DOI:10.1104/pp.20.00205
Patterson E, MacGregor DR, Heeney MM, Gallagher J, O’Connor D, Nuesslein B, Bartlett ME. 2025. Developmental constraint underlies the replicated evolution of grass awns. The new phytologist 245: 835–848.DOI:10.1111/nph.20268
Poethig RS, Fouracre J. 2024. Temporal regulation of vegetative phase change in plants. Developmental cell 59: 4–19. DOI: 10.1016/j.devcel.2023.11.010
Weiss T, Kamalu M, Shi H, Li Z, Amerasekera J, Zhong Z, Adler BA, Song M, Vohra K, Wirnowski G, et al. 2024. Viral delivery of an RNA-guided genome editor for transgene-free germline editing in Arabidopsis. bioRxiv. DOI:10.1038/s41477-025-01989-9