A one-step organelle capture: gynogenetic kiwifruits with paternal chloroplasts

Androgenesis, the development of a haploid embryo from a male nucleus, has been shown to result in the instantaneous uncoupling of the transmission of the organelle and nuclear genomes (with the nuclear genome originating from the male parent only and the organelle genomes from the female parent). We report, for the first time, uncoupling resulting from gynogenesis, in Actinidia deliciosa (kiwifruit), a plant species known for its paternal mode of chloroplast inheritance. After pollen irradiation, transmission of nuclear genes from the pollen parent to the progeny was inhibited, but transmission of the chloroplast genome was not. This demonstrates that plastids can be discharged from the pollen tube into the egg with little or no concomitant transmission of paternal nuclear genes. Such events of opposite inheritance of the organelle and nuclear genomes must be very rare in nature and are unlikely to endanger the long-term stability of the association between the different genomes of the cell. However, they could lead to incongruences between organelle gene trees and species trees and may constitute an alternative to the hybridization/introgression scenario commonly invoked to account for such incongruences.