Supervisor
Dr Madelaine Bartlett
Brief summary
Many grasses have floral organ extensions called awns, which can take on elaborate forms and have divergent roles. In this project, the student will use forward genetics, comparative transcriptomics, and microscopy to define and dissect the genetic networks underlying awn development and evolution. The student will identify the gene disrupted in an existing barley awn mutant using genomic techniques, and characterise awn development using scanning electron microscopy and anatomical techniques. Using comparative transcriptomic approaches in contrasting awn mutants, they will also dissect the genetic networks regulating awn development. The student will use transgenic approaches, including in the barley relative Brachypodium distachyon, to test hypotheses of awn evolution and development. Depending on time and student interests, there is also the possibility for the student to test hypotheses of awn function in floral biology, seedling establishment, and yield resiliency. This work will provide mechanistic understanding of how homologous organs can take on divergent forms and functions, and of the molecular genetics underlying the replicated evolution of a trait with important roles in grass biology.
Project Summary
Many grasses have floral organ extensions called awns, which can take on elaborate forms and have divergent roles. Some awns twist and untwist as water content changes, burying grains underground, and helping with seedling establishment. Other awns, like those of barley and wheat, are very long and contribute photosynthate to developing grains, which may influence seedling survival and yield resiliency. Although all awns are likely homologous to leaf blades, we know very little about the genes controlling awn emergence and morphological diversification over deep time. The Bartlett lab dissects the genetic underpinnings of awn development and evolution. This work will provide mechanistic understanding of how homologous organs can take on divergent forms and functions, and of the molecular genetics underlying the replicated evolution of a trait with important roles in grass biology.
What will the successful applicant do?
In this project, the student will use forward genetics, comparative transcriptomics, and microscopy to define and dissect the genetic networks underlying awn development and evolution. The student will identify the gene disrupted in an existing barley awn mutant using genomic techniques, and characterise awn development using scanning electron microscopy and anatomical techniques. Using comparative transcriptomic approaches in contrasting awn mutants, they will also dissect the genetic networks regulating awn development. The student will use transgenic approaches, including in the barley relative Brachypodium distachyon, to test hypotheses of awn evolution and development. Depending on time and student interests, there is also the possibility for the student to test hypotheses of awn function in floral biology, seedling establishment, and yield resiliency.
References
Patterson E, MacGregor D, Heeney M, Gallagher J, O’Connor D, Nuesslein B, Bartlett ME. (bioRxiv, in review). Deep Homology and Developmental Constraint Underlies the Replicated Evolution of Grass Awns. bioRxiv. DOI: 2024.05.30.596325
Patterson E, Richardson A, Bartlett ME (2023). Pushing the boundaries of organ identity: Homology of the grass lemma. American Journal of Botany. DOI:10.1002/ajb2.16161
Schrager-Lavelle, A, Klein, H, Fisher, A, Bartlett ME (2017). Grass Flowers: An Untapped Resource for Floral Evo-Devo. Journal of Systematics and Evolution. DOI: 10.1111/jse.12251