The Physcomitrium patens egg cell changes the epigenetic program and utilizes homologs of Arabidopsis male genes, including BONOBOs, for cell specification

We used single cell laser-assisted microdissection (LAM) to perform egg cell transcriptome analysis for comparison with available expression profiles of vegetative tissues and male reproductive organs. We observed an overlap in gene activity between bryophyte and angiosperm egg cells, but also clear differences. Strikingly, several processes that are male germline-specific in Arabidopsis are active in the P. patens egg cell. Among those were the moss PbBNB genes and using reporter lines and knock-out mutants we could show that they control proliferation and identity of both female and male germlines. Overall design: Single cell laser-assisted microdissection and RNA-seq of egg cells for comparative transcriptome analysis with available expression profiles of vegetative tissues and male reproductive organs. The processed data includes re-analyzed samples from: https://genome.jgi.doe.gov/portal/pages/dynamicOrganismDownload.jsf?organism=PhypatAtlaPlate2