1. Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom
2. Comparative Plant & Fungal Biology, Royal Botanic Gardens, Kew, Richmond TW9 3DS, United Kingdom
3. Department of Life Sciences, Imperial College London, London, SW7 2AZ, United Kingdom
4. Department of Life Sciences, Natural History Museum, London SW7 5BD, United Kingdom
5. Laboratory of Isotope Biogeochemistry, Bayreuth Center of Ecology and Environmental Research, University of Bayreuth, 95440 Bayreuth, Germany
6. Sainsbury Laboratory, University of Cambridge, Cambridge, CB2 1LR, United Kingdom