Abstract
Genetic screens are powerful tools for biological research and are one of the reasons for the success of the thale cress Arabidopsis thaliana as a model species. Here, we describe the whole-genome sequencing of 871 Arabidopsis lines from the Homozygous EMS Mutant (HEM) collection as a novel resource for forward and reverse genetics. With an average 576 high-confidence mutations per HEM line, over three independent mutations altering protein sequence are found on average per gene in the collection. Pilot reverse genetics experiments on reproductive, developmental and physiological traits confirmed the efficacy of the tool for identifying both null and knockdown alleles. The possibility of conducting subtle repeated phenotyping of HEM lines and the immediate availability of the mutations will empower forward genetic approaches. The sequence resource is searchable with the ATHEM web interface ( https://lipm-browsers.toulouse.inra.fr/pub/ATHEM/ ), and the biological material is distributed by the Versailles Arabidopsis Stock Center.