PubMed · 2026-05-21
Plants rely on specialized guardian proteins to keep their mitochondrial DNA stable and correctly organized. This study reveals how those guardian proteins evolved across the plant kingdom and shows that losing them causes the mitochondrial genome to shuffle in unexpected ways in both thale cress and rice.
Researchers catalogued 182 OSB guardian genes spread across 59 plant species, tracing how this protein family diversified from ancient algae through modern flowering plants.
Losing OSB proteins caused recombination to increase at medium-sized repetitive DNA segments in mitochondria while simultaneously decreasing at repeats longer than 1 kb — a counterintuitive two-directional effect.
Mutant plants in both Arabidopsis and rice showed uneven DNA read coverage across their mitochondrial genomes and shifts in which genome arrangement was dominant, indicating structural instability.
