Comparative analyses of five complete chloroplast genomes from the endemic genus Cremanthodium (Asteraceae) in Himalayan and adjacent areas

Physiol Mol Biol Plants. 2023 Mar;29(3):409-420. doi: 10.1007/s12298-023-01292-x. Epub 2023 Feb 27.

Abstract

Cremanthodium Benth. is an endemic genus in the Himalayas and adjacent areas. Some plants of the genus are traditional medicinal plants in Tibetan medicine. In this study, the chloroplast genomes of five species (Cremanthodium arnicoides (DC. ex Royle) Good, Cremanthodium brunneopilosum S. W. Liu, Cremanthodium ellisii (Hook. f.) Kitam., Cremanthodium nervosum S. W. Liu, and Cremanthodium rhodocephalum Diels) were collected for sequencing. The sequencing results showed that the size of the chloroplast genome ranged from 150,985 to 151,284 bp and possessed a typical quadripartite structure containing one large single copy (LSC) region (83,326-83,369 bp), one small single copy (SSC) region (17,956-18,201 bp), and a pair of inverted repeats (IR) regions (24,830-24,855 bp) in C. arnicoides, C. brunneopilosum, C. ellisii, C. nervosum, and C. rhodocephalum. The chloroplast genomes encoded an equal number of genes, of which 88 were protein-coding genes, 37 were transfer ribonucleic acid genes, and eight were ribosomal ribonucleic acid genes, and were highly similar in overall size, genome structure, gene content, and order. In comparison with other species in the Asteraceae family, their chloroplast genomes share similarities but show some structural variations. There was no obvious expansion or contraction in the LSC, SSC or IR regions among the five species, indicating that the chloroplast gene structure of the genus was highly conserved. Collinearity analysis showed that there was no gene rearrangement. The results of the phylogenetic tree showed that the whole chloroplast genomes of the five species were closely related, and the plants of this genus were grouped into one large cluster with Ligularia Cass. and Farfugium Lindl.

Keywords: Chloroplast genomes; Cremanthodium Benth.; Endemic genera; Sequencing.