Distant Hybridization in Solanaceae: Similarity to Self-Incompatibility of Pollen Tube Growth Arrest as a Reproductive Barrier

Distant hybridization in plants is a powerful tool for broadening genetic diversity and developing new varieties with improved traits. However, crosses between genetically distant species are accompanied by reproductive barriers that prevent successful fertilization. This work investigated pollen–pistil interactions during the progamic phase of fertilization in distant crosses involving four members of the Solanaceae family, using several cross combinations. In all cross combinations, pollen of all species germinated on the stigma, grew through the transmitting tissues of the style and ceased growth at a specific distance from the stigma surface. Our studies have revealed that the arrest of pollen tube growth during distant hybridization exhibits a striking similarity to that observed in the gametophytic S-RNase-based self-incompatibility mechanism of Solanaceae plants. Elucidating the mechanisms of pollen tube growth arrest during distant hybridization in Solanaceae will provide deeper insight into the nature of reproductive barriers and aid in the development of strategies to overcome them, thereby expanding the possibilities for successful hybridization between distant species and enabling the creation of valuable new varieties.