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Experimental systems for Synthetic Biology
We use a range of experimental systems in the lab. Microbial systems, including Escherichia coli and Bacillus subtilis allow simple and fast assembly of genetic circuits, and testing of methods for cell-cell communication. Our main interest is in building systems to manipulate morphogenesis in plants, and we work with a number of model plants systems including algae and lower plants.
Bacillus subtilis
Bacillus subtilis is a non-pathogenic soil bacterium. It is perhaps the best characterised microbe after Escherichia coli, and there is a comprehensive set of tools for genetic analysis and manipulation of the species. The bacteria are naturally competent, and synthetic genetic circuits can be introduced into the bacterial chromosome by homologous recombination, and maintained as single, stable copies. It is a Gram positive bacterium, allowing the simple secretion of extracellular peptides, and extracellular signalling is used to trigger cell differentiation during sporulation and growth. It is a useful system for prototyping synthetic circuits.
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Coleochaete orbicularis
This genus of green algae shows some of the earliest and simplest features of multicellular plant growth. Haploid zoospores initiate the growth of discoid multicellular colonies. The colonies adhere to the substrate and grow as a cell monolayer. The circular morphology of the colonies is maintained by precisely coordinated sequences of anticlinal and periclinal divisions. Cultures are easy to maintain, and are ideal for microscopy.
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Marchantia polymorpha
Marchantia is a liverwort, which were among the first terrestrial plants. The dominant form of the life cycle is haploid. The plants are commonly found as weeds in horticultural nurseries. They reproduce vegetatively and via spores. Marchantia polymorpha is becoming a major new system for developmental biology - it can be easily transformed and regenerated. The genome is currently being sequenced, and its gene organisation appears highly steamlined with little genetic redundancy.
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Arabidopsis thaliana
Arabidopsis grows quickly, produces prolific seed, and is easy to transform. Its genome is completely sequenced and a large variety of experimental tools and genetic resources are available. The root meristem grows indeterminately, has a simple and transparent 3D architecture, and can be induced to form de novo in adult tissues. We have developed a combination of new genetic and microscopy techniques for Arabidopsis in order to visualise cell interactions and gene expression within plant tissues, and to reprogram plant gene expression.
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