EVIDENCE FOR RNA EDITING IN MITOCHONDRIA OF ALL MAJOR GROUPS OF LAND PLANTS EXCEPT THE BRYOPHYTA

RNA editing has been documented in mito chondria of higher plants, notably dicots and monocots. To determine the distribution of mitochondrial RNA editing in the plant kingdom, we have now undertaken a survey of evolutionarily distant plants. RNA editing occurs in all major groups of land plants except the Bryophyta, suggesting that this process is an ancient trait that was established before the radiation of kormophyte plants. No editing is observed in representatives of the green algae, suggesting that editing arose in early land plants after the split of the Bryophyta or has been lost selectively in both algae and mosses. In ferns several U --> C changes are observed, one of which eliminates a genomically encoded UAA termination codon and creates a functional open reading frame.