1 Ghent University, Department of Plant Biotechnology and Bioinformatics, VIB-UGent Center for Plant Systems Biology, Technologiepark 71, B-9052 Ghent, Belgium. Electronic address: woboe@psb.ugent.be.
2 Departments of Biochemistry and Biological Systems Engineering, and the Department of Energy's Great Lakes Bioenergy Research Center, The Wisconsin Energy Institute, The University of Wisconsin, Madison, WI 53726, USA.