Organelle Genome Inheritance in Angiosperms

In flowering plants, the genomes of cytoplasmic organelles – mitochondria and plastids – are typically inherited from the maternal parent, insulating them from the recombination that operates on nuclear DNA. This uniparental bias arises through coordinated cellular processes that exclude or degrade paternal organelles during pollen development and fertilisation. Advances in molecular genetics have revealed that maternal inheritance can be overridden under specific environmental or genetic conditions, leading to occasional paternal leakage or biparental transmission and resulting heteroplasmy within a single individual. These patterns have profound implications for phylogenetic inference, crop improvement and hybrid breeding, as organelle genomes influence key traits such as fertility, stress tolerance and metabolic efficiency. A refined understanding of the mechanisms governing organelle inheritance illuminates how gene–environment interactions shape plant evolution and offers strategies to manipulate cytoplasmic genomes for agricultural innovation.

Research from Nature Portfolio

Recent studies have demonstrated that plastid inheritance is governed by two parallel mechanisms: an organelle exclusion process that physically prevents paternal plastids from entering the germline, and an exonuclease-mediated genome degradation pathway that dismantles any genomes that bypass exclusion. Mild chilling stress during pollen formation was shown to disrupt exclusion, permitting paternal plastids to enter sperm cells and be transmitted to the next generation. The interplay between environmental cues and genetic factors thus dictates the fidelity of maternal plastid inheritance.

Investigation of narrow endemic species in isolated savannah ecosystems has uncovered unexpected paternal contributions to chloroplast variation. Analysis of chloroplast DNA loci revealed distinct paternal haplotypes and strong genetic differentiation among populations, implying that occasional paternal inheritance is essential to generate cytoplasmic diversity and may influence speciation in fragmented habitats.

Organelle Genome Inheritance in Angiosperms publication trend

The graph below shows the total number of articles in organelle genome inheritance in angiosperms across all publications each year (not limited to Nature Index journals).

Technical terms

Organelle exclusion: A cellular process that prevents paternal plastids or mitochondria from entering germ cells.

Exonuclease: An enzyme that degrades DNA, here acting to dismantle unwanted organelle genomes.

Biparental inheritance: Transmission of organelle genomes from both maternal and paternal parents.

Heteroplasmy: Coexistence of more than one organelle genome type within a single cell or individual.

Paternal leakage: Occasional transmission of paternal organelle genomes despite dominant maternal inheritance.

Cyto-nuclear incompatibility: Mismatch between organelle and nuclear genomes that can reduce hybrid fitness.

References

1. Control of plastid inheritance by environmental and genetic factors. Nature Plants (2023).
2. Plastid-encoded RNA polymerase variation in Pelargonium sect Ciconium. Horticulture Advances (2024).
3. Clade-Specific Plastid Inheritance Patterns Including Frequent Biparental Inheritance in Passiflora Interspecific Crosses. International Journal of Molecular Sciences (2021).
4. Chloroplast competition is controlled by lipid biosynthesis in evening primroses. Proceedings of the National Academy of Sciences of the United States of America (2019).