Abstract:
Hagenia is an endangered monotypic genus endemic to the topical mountains of Africa.
The only species, Hagenia abyssinica (Bruce) J.F. Gmel, is an important medicinal plant
producing bioactive compounds that have been traditionally used by African communities
as a remedy for gastrointestinal ailments in both humans and animals. Complete
chloroplast genomes have been applied in resolving phylogenetic relationships within
plant families. We employed high-throughput sequencing technologies to determine
the complete chloroplast genome sequence of H. abyssinica. The genome is a circular
molecule of 154,961 base pairs (bp), with a pair of Inverted Repeats (IR) 25,971 bp
each, separated by two single copies; a large (LSC, 84,320 bp) and a small single copy
(SSC, 18,696). H. abyssinica's chloroplast genome has a 37.1% GC content and encodes
112 unique genes, 78 of which code for proteins, 30 are tRNA genes and four are
rRNA genes. A comparative analysis with twenty other species, sequenced to-date from
the family Rosaceae, revealed similarities in structural organization, gene content and
arrangement. The observed size differences are attributed to the contraction/expansion
of the inverted repeats. The translational initiation factor gene (infA) which had been
previously reported in other chloroplast genomes was conspicuously missing in H.
abyssinica. A total of 172 microsatellites and 49 large repeat sequences were detected in
the chloroplast genome. A Maximum Likelihood analyses of 71 protein-coding genes
placed Hagenia in Rosoideae. The availability of a complete chloroplast genome, the
first in the Sanguisorbeae tribe, is beneficial for further molecular studies on taxonomic
and phylogenomic resolution within the Rosaceae family.
