PubMed · 2026-04-22
Scientists discovered that apple seeds carry their own communities of bacteria, inherited through two distinct pathways: via flower parts (sexual) and through the tree's vascular system (asexual). Surprisingly, nearly half the seed microbiome came from unknown sources, suggesting there are transmission routes yet to be identified.
Both sexual (30.3%, via pollen and ovary) and asexual (23.8%, via the tree's vascular spurs) pathways contribute to seed microbiome assembly in apple trees.
Branch spurs sampled before bloom had significantly higher bacterial richness and diversity than all other tissue types, including seeds, ovaries, and pollen.
45.9% of the apple seed microbiome could not be attributed to any measured source, indicating major unknown transmission routes remain undiscovered.
