A female in vivo haploid-induction system via mutagenesis of egg cell-specific peptidases

Abstract Crop breeding schemes can be significantly accelerated by using (doubled) haploid plants. In vivo haploid induction has been applied in plant breeding since decades, but is still not available for all crops, genotypes and haploidization rates are very low1-3. Therefore, plant breeders are highly interested in methodological improvements, especially, in new concepts to haploidization. Here, we report a novel system for the induction of haploid plants by mutating genes encoding egg cell-specific aspartic endopeptidases (ECSs). After successful sperm-egg fusion, ECSs play a critical role to ensure male and female nucleus fusion and parental genome incorporation. The ecs1 ecs2 double mutant pollinated by wild type pollen is capable to produce haploid offspring originating from semigamous zygotes. Chromosome elimination occurs during zygote and early embryo development. In summary, we report a novel approach for haploidization and additionally provide new insights into the molecular basis of fertilization.