This material is based upon work supported by the Center for Bioenergy Innovation(CBI),U.S.Department of Energy,Office of Science,Biological and Environmental Research Program under Award Number ERKP886 and by the Genomics enabled Plant Biology for Determination of Gene Function programme by the Office of Biological and Environmental Research in the DOE Office of Science(DE-SC0020164). This manuscript has been authored by UT-Battelle,LLC under Con-tract No.DE-AC05-00OR22725 with the U.S.Department of Energy.The United States Government retains and the publisher,by accepting the article for publication,acknowledges that the United States Government retains a non-exclusive,paid-up,irrevocable,world-wide license to publish or reproduce the published form of this manuscript,or allow others to do so,for United States Government purposes.The Department of Energy will provide public access to these results of federally spon-sored research in accordance with the DOE Public Access Plan(http://energy.gov/downloads/doe-public-access-plan).MCK acknowledges the Department of Plant Sciences,UC Davis,for awarding a GSR scholarship funded by endowments,particularly the James Monroe McDonald Endowment,administered by UCANR.Research in the laboratory of GT was funded by the John B.Orr Chair Endowment,by the Genomics enabled Plant Biology for Determination of Gene Function programme by the Office of Biological and Environ-mental Research in the DOE Office of Science(DE-SC0020164)and as Quain Professor of Botany,University College,London. （CBI）