TY - JOUR
T1 - Evolution of six novel ORFs in the plastome of Mankyua chejuense and phylogeny of eusporangiate ferns
AU - Kim, Hyoung Tae
AU - Kim, Ki Joong
N1 - Funding Information:
This work was supported by the National Research Foundation of Korea (NRF) under grant nos. NRF-2015M3A9B8030588 to KJK and NRF-2018R1D1A3B07048213 to HTK. We thank two anonymous reviewers for helpful comments on the manuscript.
PY - 2018/12/1
Y1 - 2018/12/1
N2 - In this paper, three plastomes of Mankyua chejuense, Helminthostachys zeylanica, and Botrychium ternatum in Ophioglossaceae were completely sequenced in order to investigate the plastome evolution and phylogeny of eusporangiate ferns. They were similar to each other in terms of length and the gene orders; however, six unknown open reading frames (ORFs) were found between rps4 and trnL-UAA genes in M. chejuense. Similar sequence regions of six ORFs of M. chejuense were found at the plastomes of Ophioglossum californicum and H. zeylanica, as well as the mitochondrial genome (mitogenome) of H. zeylanica, but not in B. ternatum. Interestingly, the translated amino acid sequences of three ORFs were more similar to the proteins of distantly related taxa such as algae and bacteria than they were to proteins in land plants. It is likely that the six ORFs region arose from endosymbiotic gene transfer (EGT) or horizontal gene transfer (HGT), but further study is needed to verify this. Phylogenetic analyses suggested that Mankyua was resolved as the earliest diverging lineage and that Ophioglossum was subsequently diverged in Ophioglossaceae. This result supports why the plastome of M. chejuense have contained the most ancestral six ORFs in the family.
AB - In this paper, three plastomes of Mankyua chejuense, Helminthostachys zeylanica, and Botrychium ternatum in Ophioglossaceae were completely sequenced in order to investigate the plastome evolution and phylogeny of eusporangiate ferns. They were similar to each other in terms of length and the gene orders; however, six unknown open reading frames (ORFs) were found between rps4 and trnL-UAA genes in M. chejuense. Similar sequence regions of six ORFs of M. chejuense were found at the plastomes of Ophioglossum californicum and H. zeylanica, as well as the mitochondrial genome (mitogenome) of H. zeylanica, but not in B. ternatum. Interestingly, the translated amino acid sequences of three ORFs were more similar to the proteins of distantly related taxa such as algae and bacteria than they were to proteins in land plants. It is likely that the six ORFs region arose from endosymbiotic gene transfer (EGT) or horizontal gene transfer (HGT), but further study is needed to verify this. Phylogenetic analyses suggested that Mankyua was resolved as the earliest diverging lineage and that Ophioglossum was subsequently diverged in Ophioglossaceae. This result supports why the plastome of M. chejuense have contained the most ancestral six ORFs in the family.
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U2 - 10.1038/s41598-018-34825-6
DO - 10.1038/s41598-018-34825-6
M3 - Article
C2 - 30405200
AN - SCOPUS:85056123276
VL - 8
JO - Scientific Reports
JF - Scientific Reports
SN - 2045-2322
IS - 1
M1 - 16466
ER -