New target found in search for new, more effective herbicide

Scientists at the John Innes Centre have discovered a new target in plants for the development of new herbicides for use by farmers and gardeners.

Professor Tony Maxwell leads a research team at the John Innes Centre studying an enzyme in plants called DNA gyrase. In plants, DNA gyrase plays an essential role in the formation of chloroplasts, which are the parts of the plant that give it its green colour and help it to transform sunlight into energy. Without DNA gyrase, the plant is not able to photosynthesise and will die.

DNA gyrase performs an equally important role in bacteria - without this enzyme bacteria will also die. It is known that DNA gyrase in bacteria is an important target for an antibiotic called ciprofloxacin. When bacteria are treated with ciprofloxacin, the DNA gyrase in their cells doesn't work and the bacteria dies.

Scientists also knew that ciprofloxacin kills plants but they didn't know how it does this. Professor Maxwell's team set to work investigating whether the antibiotic had the same effect on the DNA gyrase in plants as it does in bacteria.

They mutated 400,000 Arabidopsis thaliana seeds and grew them into plants. They then treated them with ciprofloxacin and found one plant which had increased resistance to the antibiotic. From analysis of its genome, the team found that the plant had a mutation in a very specific gene known to encode the enzyme DNA gyrase. This demonstrated that the plant version of DNA gyrase is a target for ciprofloxacin but most importantly it shows that DNA gyrase can be used as a target for herbicides because it is essential for plant growth.

This research in no way recommends the use of antibiotics as herbicides. Professor Maxwell said:

"The next step is to find new compounds that can target DNA gyrase in a different way to avoid the potential for developing resistance to medically used antibiotics. These compounds could then be developed and tested as future herbicides."

This research, which is published in the Journal of Biological Chemistry, also highlights another important benefit for using DNA gyrase as a target for the development of new herbicides. DNA gyrase is only present in plants and bacteria, and does not exist in animals. Therefore any new herbicides that target this DNA gyrase in plants are very unlikely to be any danger to humans.

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The John Innes Centre receives strategic funding from the Biological and Biotechnology Research Council (BBSRC). This work was performed in collaboration with the research team of Dr Joshua Mylne from the University of Western Australia and is funded by the BBSRC with support from Syngenta.

1. The paper 'DNA Gyrase is the target for the quinolone drug Ciprofloxacin in Arabidopsis thaliana' is available to view at http://bit.ly/20NP2zo. It will be published in the hard copy of the Journal of Biological Chemistry on Friday 12 February.

2. If you have any questions or wish to speak to Professor Maxwell please contact:
Geraldine Platten
Communications Manager, the John Innes Centre
T: 01603 450 238
E: geraldine.platten@jic.ac.uk

3. About the John Innes Centre

Our mission is to generate knowledge of plants and microbes through innovative research, to train scientists for the future, to apply our knowledge of nature's diversity to benefit agriculture, the environment, human health and wellbeing, and engage with policy makers and the public.

To achieve these goals we establish pioneering long-term research objectives in plant and microbial science, with a focus on genetics. These objectives include promoting the translation of research through partnerships to develop improved crops and to make new products from microbes and plants for human health and other applications. We also create new approaches, technologies and resources that enable research advances and help industry to make new products. The knowledge, resources and trained researchers we generate help global societies address important challenges including providing sufficient and affordable food, making new products for human health and industrial applications, and developing sustainable bio-based manufacturing.

This provides a fertile environment for training the next generation of plant and microbial scientists, many of whom go on to careers in industry and academia, around the world.

The John Innes Centre is strategically funded by the Biotechnology and Biological Sciences Research Council (BBSRC). In 2014-2015 the John Innes Centre received a total of £36.9 million from the BBSRC.

4. About the BBSRC

The Biotechnology and Biological Sciences Research Council (BBSRC) invests in world-class bioscience research and training on behalf of the UK public. Our aim is to further scientific knowledge, to promote economic growth, wealth and job creation and to improve quality of life in the UK and beyond.

Funded by Government, BBSRC invested over £509M in world-class bioscience in 2014-15. We support research and training in universities and strategically funded institutes. BBSRC research and the people we fund are helping society to meet major challenges, including food security, green energy and healthier, longer lives. Our investments underpin important UK economic sectors, such as farming, food, industrial biotechnology and pharmaceuticals.

For more information about BBSRC, our science and our impact see: http://www.bbsrc.ac.uk .