Chloroplast Genome Provides Insights into Molecular Evolution and Species Relationship of Fleabanes (Erigeron: Tribe Astereae, Asteraceae) in the Juan Fernández Islands, Chile

Abstract

Erigeron represents the third largest genus on the Juan Fernández Islands, with six endemic species, five of which occur exclusively on the younger Alejandro Selkirk Island with one species on both islands. While its continental sister species is unknown, Erigeron on the Juan Fernández Islands appears to be monophyletic and most likely evolved from South American progenitor species. We characterized the complete chloroplast genomes of five Erigeron species, including accessions of E. fernandezia and one each from Alejandro Selkirk and Robinson Crusoe Islands, with the purposes of elucidating molecular evolution and phylogenetic relationships. We found highly conserved chloroplast genomes in size, gene order and contents, and further identified several mutation hotspot regions. In addition, we found two positively selected chloroplast genes (ccsA and ndhF) among species in the islands. The complete plastome sequences confirmed the monophyly of Erigeron in the islands and corroborated previous phylogenetic relationships among species. New findings in the current study include (1) two major lineages, E. turricola–E. luteoviridis and E. fernandezia–E. ingae–E. rupicola, (2) the non-monophyly of E. fernandezia occurring on the two islands, and (3) the non-monophyly of the alpine species E. ingae complex.

Complete Chloroplast Genome of Alternanthera sessilis and Comparative Analysis with Its Congeneric Invasive Weed Alternanthera philoxeroides

“…CcsA encodes cytochrome c biogenesis protein, which mediates the attachment of heme to c-type cytochromes [69]. It has been shown that ccsA was under positive selection in the epiphytic orchid [70] and Erigeron [71]. Both of them have been found to contribute to adaption to environmental changes in other species, for example, Lilium Ledebourii and the species in Malvaceae subfamilies [72,73].…”