Variation in frequency of plastid RNA editing within Adiantum (Pteridaceae) implies rapid evolution in fern plastomes

Premise

Recent advances in studies of plant RNA editing have demonstrated that the number of editing sites can vary widely among large taxonomic groups (orders, families). Yet, very little is known about intrageneric variation in frequency of plant RNA editing, and no study has been conducted in ferns.

Methods

We determined plastid RNA editing counts for two species of Adiantum (Pteridaceae), A. shastense and A. aleuticum, by implementing a pipeline that integrated read mapping and SNP calling software to identify RNA editing sites. We then compared the edits found in A. aleuticum and A. shastense with previously published edits from A. capillus-veneris by generating alignments for each plastid gene.

Results

We found direct evidence for 505 and 509 plastid RNA editing sites in A. aleuticum and A. shastense, respectively, compared with 350 sites in A. capillus-veneris. We observed striking variation in the number and location of the RNA editing sites among the three specie...