High temperature disrupts sporocyte development in Camellia meiocarpa.

High temperature has a significant impact on plant reproductive development, driving the formation of 2n gametes by interfering with the meiosis and cytokinesis of sporocytes. This study used Camellia meiocarpa as the material, integrating cytological and molecular biology approaches to reveal the cytological effects and regulatory mechanisms of high temperature on sporocyte development. The results showed that meiosis in microsporocyte and megasporocyte of C. meiocarpa exhibits pronounced spatiotemporal heterogeneity. High temperature markedly disrupted sporocyte development and induced abnormal phenomena, inducing disordered cytokinesis, leading to the formation of dyads, triads in microsporocyte, as well as multinucleate cells occurring during the development of megaspores into mature embryo sacs. RNA-seq sequencing analysis indicates that the CoNPK1 gene may regulate meiotic and cytokinetic behavior in response to high temperature. Meanwhile, heterologous transformation in tobacco verified that the CoNPK1 gene induces the formation of dyads and triads through upregulated expression, which further leads to the production of 2n gametes. We speculate that the CoNPK1 gene regulates cell plate synthesis via the mitogen-activated protein kinase (MAPK) signaling pathway, thereby affecting cytokinesis and generating 2n gametes. This lays a theoretical foundation for ploidy breeding of woody oil crops.