A cytological framework of female meiosis in Arabidopsis

Female and male meiosis often differ in many aspects, such as their duration and the frequency as well as the positioning of crossovers. However, studying female meiosis is often very challenging and thus, much less is known about female versus male meiosis in many species including plants, where meiosis occurs deep within the ovules. To approach this gap, we developed a live-cell imaging system for female meiocytes in Arabidopsis (Arabidopsis thaliana) in this study. This allowed us to obtain a temporally resolved cytological framework of female meiosis in the wild type that serves as a guiding system for future studies. Subsequently, we have applied this imaging system here to study mutants in cyclin-dependent kinase inhibitors, in which a designated female meiocyte undergoes several mitotic divisions before entering meiosis. This mutant context enabled us to address when a meiocyte is committed to meiosis, a key question during reproductive development and in particular for the analysis of apomictic species in which meiosis is skipped.