Department of Plant Sciences, Cambridge University, Cambridge CB2 3EA, UK, School of Informatics, Edinburgh University, Edinburgh EH8 9AB, Scotland and Microsoft Research, Cambridge CB1 2FB, UK.|Department of Plant Sciences, Cambridge University, Cambridge CB2 3EA, UK, School of Informatics, Edinburgh University, Edinburgh EH8 9AB, Scotland and Microsoft Research, Cambridge CB1 2FB, UK.|Department of Plant Sciences, Cambridge University, Cambridge CB2 3EA, UK, School of Informatics, Edinburgh University, Edinburgh EH8 9AB, Scotland and Microsoft Research, Cambridge CB1 2FB, UK.|Department of Plant Sciences, Cambridge University, Cambridge CB2 3EA, UK, School of Informatics, Edinburgh University, Edinburgh EH8 9AB, Scotland and Microsoft Research, Cambridge CB1 2FB, UK.