Publication Date:
2016-01-23
Description:
The 23 species of mycoheterotrophic or exoparasitic land plants (from 15 genera and 6 families) studied so far all retain a minimal set of 17 of the normally 116 plastome genes. Only Rafflesia lagascae , an endoparasite concealed in its host except when flowering, has been reported as perhaps lacking a plastome, although it still possesses plastid-like compartments. We analyzed two other endoparasites, the African Apodanthaceae Pilostyles aethiopica and the Australian Pilostyles hamiltonii , both living inside Fabaceae. Illumina and 454 data and Sanger resequencing yielded circularized plastomes of 11,348 and 15,167 bp length, with both species containing five possibly functional genes ( acc D, rps 3, rps 4, rrn 16, rrn 23) and two/three pseudogenes ( rpo C2 in P. aethiopica and rpl 2 and rps 12 in both species; rps 12 may be functional in P. hamiltonii ). Previously known smallest land plant plastomes contain 27–29 genes, making these Apodanthaceae plastomes the most reduced in size and gene content. A similar extent of divergence might have caused the plastome of Rafflesia to escape detection. The higher plastome degeneration in both these families of endoparasites, Rafflesiaceae and Apodanthaceae, of similar high age, compared with exoparasites points to a difference of plastome function between those two modes of parasitic life.
Electronic ISSN:
1759-6653
Topics:
Biology
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