BABY BOOM regulates early embryo and endosperm development.

The BABY BOOM (BBM) AINTEGUMENTA-LIKE (AIL) AP2/ERF domain transcription factor is a major regulator of plant cell totipotency, as it induces asexual embryo formation when ectopically expressed. Surprisingly, only limited information is available on the role of during zygotic embryogenesis. Here we reexamined expression and function in the model plant () using reporter analysis and newly developed CRISPR mutants. was expressed in the embryo from the zygote stage and also in the maternal (nucellus) and filial (endosperm) seed tissues. Analysis of CRISPR mutant alleles for () and the redundantly acting gene () () uncovered individual roles for these genes in the timing of embryo progression. We also identified redundant roles for and in endosperm proliferation and cellularization and the maintenance of zygotic embryo development. Finally, we show that ectopic expression in the egg cell of and the dicot crops and is sufficient to bypass the fertilization requirement for embryo development. Together these results highlight roles for and in seed development and demonstrate the utility of genes for engineering asexual embryo development in dicot species.