Understanding the Functional Megaspore Development: Current Status/Progress, Perspectives

ABSTRACT In most angiosperms, female gametogenesis originates from a specifically selected haploid megaspore, as three out of the four megaspores produced by meiosis degenerate without undergoing further division or differentiation. The remaining megaspore acquires functional megaspore (FM) identity, becoming the FM, which is essential for plant reproductive development. However, the molecular mechanisms governing FM development (or megaspore degeneration) remain largely unexplored, with current studies focusing on only a limited number of genes or regulatory networks. To date, no comprehensive review has systematically introduced advances in this field. This review aims to highlight recent progress in understanding FM development, discuss its critical role in female reproductive development and prospect the mechanism of FM development in environmental adaptation. By offering new insights, this review enriches existing knowledge of FM development and provides fresh perspectives for future research in plant reproduction and its adaptation to the environment.