Conservation and Functional Analysis of Synthetic Apomixis-Related Genes in Pepper

The engineering of synthetic apomixis holds significant promise for fixing heterosis, yet its effective application has thus far been limited to Arabidopsis , rice, and tomato. Whether the molecular mechanism of synthetic apomixis is universal in vegetable crops is a scientific question of great concern. As one important vegetable crop, pepper ( Capsicum annuum ) primarily relies on crossbreeding for varietal improvement, necessitating significant resource allocation annually. In this study, we identified three important genes associated with synthetic apomixis in pepper, namely CaSPO11-1 , CaREC8 , and CaOSD1 . CaSPO11-1 associates with CaMTOPVIB to form a complex, and its silencing impairs homologous chromosome pairing, synapsis, and segregation. CaREC8 exhibits functional conservation, and its suppression disrupts the typical aggregation of chromosomes during prophase of meiosis and prematurely separates sister chromatids during anaphase I. The silencing of CaOSD1 causes the omission of the second meiotic division, resulting in dyads. Moreover, RNA-seq analysis revealed that silencing these genes induced alterations in the expression of genes associated with meiosis. Notably, direct protein-protein interactions between CaOSD1 and CaAPC7/8/10 have been revealed, indicating distinct regulatory mechanisms of OSD1 homologs in Solanaceae crops. Overall, our findings offer new perspectives on the roles of CaSPO11-1 , CaREC8 , and CaOSD1 in meiosis and provide a reference for the potential application of engineering synthetic apomixis in pepper.