Escamez, S. - Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, 901 87, Sweden;
André, D. - Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, 901 87, Sweden;
Sztojka, B. - Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, 901 87, Sweden;
Bollhöner, B. - Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, 901 87, Sweden;
Hall, H. - Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, 901 87, Sweden;
Berthet, B. - Center for Organismal Studies (COS), University of Heidelberg, Im Neuenheimer Feld 230, Heidelberg, 69120, Germany;
Voß, U. - Centre for Plant Integrative Biology, University of Nottingham, Nottingham, LE12 SRD, United Kingdom;
Maizel, A. - Center for Organismal Studies (COS), University of Heidelberg, Im Neuenheimer Feld 230, Heidelberg, 69120, Germany;
Andersson, M. - Department of Physics, Umeå University, Umeå, 901 87, Sweden;
Bennett, M. - Centre for Plant Integrative Biology, University of Nottingham, Nottingham, LE12 SRD, United Kingdom;
Tuominen, H. - Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, 901 87, Sweden.
Plant organ growth is widely accepted to be determined by cell division and cell expansion, but, unlike that in animals, the contribution of cell elimination has rarely been recognized. We investigated this paradigm during Arabidopsis lateral root formation, when the lateral root primordia (LRP) must traverse three overlying cell layers within the parent root. A subset of LRP-overlying cells displayed the induction of marker genes for cell types undergoing developmental cell death, and their cell death was detected by electron, confocal, and light sheet microscopy techniques. LRP growth was delayed in cell-death-deficient mutants lacking the positive cell death regulator ORESARA1/ANAC092 (ORE1). LRP growth was restored in ore1-2 knockout plants by genetically inducing cell elimination in cells overlying the LRP or by physically killing LRP-overlying cells by ablation with optical tweezers. Our results support that, in addition to previously discovered mechanisms, cell elimination contributes to regulating lateral root emergence. Escamez et al. report that a subset of cells overlying newly formed lateral roots within the parent root dies to facilitate early lateral root organ growth. Our findings suggest that, contrary to common belief, cell death can, as in animals, regulate organ growth in plants, which may have implications for our understanding of evolution.