AUTHOR=Sablok Gaurav , Amiryousefi Ali , He Xiaolan , Hyvönen Jaakko , Poczai Péter 

TITLE=Sequencing the Plastid Genome of Giant Ragweed (Ambrosia trifida, Asteraceae) From a Herbarium Specimen

JOURNAL=Frontiers in Plant Science

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2019.00218

DOI=10.3389/fpls.2019.00218

ISSN=1664-462X

ABSTRACT=<p>We report the first plastome sequence of giant ragweed (<italic>Ambrosia trifida</italic>); with this new genome information, we assessed the phylogeny of Asteraceae and the transcriptional profiling against glyphosate resistance in giant ragweed. Assembly and genic features show a normal angiosperm quadripartite plastome structure with no signatures of deviation in gene directionality. Comparative analysis revealed large inversions across the plastome of giant ragweed and the previously sequenced members of the plant family. Asteraceae plastid genomes contain two inversions of 22.8 and 3.3 kb; the former is located between <italic>trn</italic>S-GCU and <italic>trn</italic>G-UCC genes, and the latter between <italic>trn</italic>E-UUC and <italic>trn</italic>T-GGU genes. The plastid genome sequences of <italic>A. trifida</italic> and the related species, <italic>Ambrosia artemisiifolia</italic>, are identical in gene content and arrangement, but they differ in length. The phylogeny is well-resolved and congruent with previous hypotheses about the phylogenetic relationship of Asteraceae. Transcriptomic analysis revealed divergence in the relative expressions at the exonic and intronic levels, providing hints toward the ecological adaptation of the genus. Giant ragweed shows various levels of glyphosate resistance, with introns displaying higher expression patterns at resistant time points after the assumed herbicide treatment.</p>