Comparative Transcriptomics Identifies Different Gene Expression Networks Regulating Gametic Development in Arabidopsis

Gamete development is a complex process during the plant reproductive life cycle. A global vision of the molecular mechanisms regulating gametic development would enhance our understanding of developmental similarities and differences between male and female reproductive pathways in plants. In this study, we applied comparative transcriptomics to characterize gene expression during sporogenesis and gametogenesis in Arabidopsis . Compared with genes expressed in leaves, 11,112 and 10,133 differentially expressed genes (DEGs) were identified in the anthers and ovules, respectively. The shared DEGs exhibited a similar expression pattern regarding cell cycle and chromatin dynamics, but DEGs associated with cell wall formation and pectin modifications were prevalent during male development, reflecting dynamic changes during pollen wall development in anthers. In contrast, DEGs related to DNA repair, homologous recombination, and RNA-directed DNA methylation (RdDM) were comparatively over-represented in ovules, probably indicating a relatively intensified mechanism for supervising genome fidelity during female gametogenesis. In addition, DEGs related to brassinolide (BR) synthesis and signaling pathway were also highly enriched in ovules, suggesting a pivotal role in female gamete development. Collectively, our results provide a contrasting transcriptional atlas in developing anthers and ovules, and shed new light on our global understanding of gamete development in plants.