1. Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, USA
2. IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM), UMR IRD/SupAgro/INRA/UM2/CIRAD, Montpellier, France
3. Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Naples, Italy
4. CIRAD, UMR BGPI, Montpellier, France
5. Howard Hughes Medical Institute, Pasadena, California, USA
6. Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA