Into the loop

Mobile phones. Almost ubiquitous, it’s easy to take them for granted, but our pocket computers are marvels of miniaturisation, promising unbridled connectivity. Their potential seems without limits.

That is, until you take your new phone out of the box and realise that the charging port doesn’t match the ends of any of the cables you already have.

How annoying. Until recently, plant biologists have faced a similar problem. The development of DNA assembly techniques has allowed plant biologists to create synthetic DNA of increasing complexity. These DNA building blocks can be inserted into plant cells and used to experiment with the biological programming that makes plants function.

As DNA assembly techniques have grown in size and sophistication, so too has the complexity of the methods associated with them. Add to this restrictive intellectual property practices and material transfer agreements, and sharing those DNA building blocks becomes difficult. Much like trying to charge a phone with the wrong cable.

Bernardo PollakJim Haseloff and colleagues have devised a solution to this problem. The scientists have designed a new technique for assembling DNA based on alternate use of two DNA cleavage enzymes, BsaI and SapI. The technique, called Loop Assembly, allows DNA building blocks to be assembled quickly and efficiently to produce large and complicated synthetic DNA structures, that can then be inserted into plants.

Multi-spectral confocal projection of a Marchantia polymorpha gemma expressing three fluorescent reporters. Courtesy of Dr. Bernardo Pollak and Prof. Jim Haseloff, Department of Plant Sciences, University of Cambridge

The intriguing image on the cover of New Phytologist 222:1 shows a gemma from the liverwort Marchantia polymorpha, lit up by three fluorescent reporters that highlight distinct features. The reporters indicate the successful functioning of a DNA structure, built using the Loop Assembly technique in less than a week.

Pollak and colleagues aimed to produce a method that was backwards-compatible with other DNA building block construction techniques being used in the plant science community. Loop Assembly is compatible with two of the main techniques – Gibson assembly, and Type IIS assembly. As well as ensuring that it is widely compatible, the scientists have shared their new technique using an Open Materials Transfer Agreement (OpenMTA), which makes it available for all to use and share.

While the lack of standardised connectors for our phones and other devices is likely to frustrate us for some time to come, the development of Loop Assembly should remove some problematic barriers from the sharing of research in the plant science world.

Read the paper: Pollak, B., Cerda, A., Delmans, M., Álamos, S., Moyano, T., West, A., Gutiérrez, R. A., Patron, N., Federici, F. and Haseloff, J. (2019) Loop assembly: a simple and open system for recursive fabrication of DNA circuitsNew Phytologist. doi: 10.1111/nph.15625

Mike Whitfield
Development Coordinator
New Phytologist Trust