Characterization of the complete chloroplast genome of medicinal tea tree (Melaleuca alternifolia)

The complete sequence of chloroplast genome of Baeckea frutescens Linaeus 1753 (Myrtoideae), a traditional folk medicinal plant

Baeckea frutescens Linaeus 1753, as a traditional folk medicine in South East Asia, possesses sesquiterpenes, phloroglucinols, chromones, and essential oil, and is utilized for traditional Chinese medicinal purposes. The genetic diversity of the plant must be better understood, considering its significance. The complete chloroplast (cp) genome of B. frutescens was sequenced and assembled by using Illumina paired-end data, marking a significant advancement toward comprehending its genetic composition. The complete cp genome is 158,939 bp in length and contains 128 genes, consisting of 83 protein-coding genes, 8 ribosomal RNA genes, and 37 transfer RNA genes. Phylogenetic analyses indicated that B. frutescens and other the 13 were clustered to the family of Myrtaceae. These findings are crucial for the conservation and utilization of this important plant species. Additionally, they underscore the potential for future research on the evolution and preservation of B. frutescens, which could be advantageous in pharmaceutical applications.

Perspectives in Myrtaceae evolution from plastomes and nuclear phylogenies

Myrtaceae is a large and species-rich family of woody eudicots, with prevalent distribution in the Southern Hemisphere. Classification and taxonomy of species belonging to this family is quite challenging, sometimes with difficulty in species identification and producing phylogenies with low support for species relationships. Most of the current knowledge comes from few molecular markers, such as plastid genes and intergenic regions, which can be difficult to handle and produce conflicting results. Based on plastid protein-coding sequences and nuclear markers, we present a topology for the phylogenetic relationships among Myrtaceae tribes. Our phylogenetic estimate offers a contrasting topology over previous analysis with fewer markers. Plastome phylogeny groups the tribes Syzygieae and Eucalypteae and individual chloroplast genes produce divergent topologies, especially among species within Myrteae tribe, but also in regard to the grouping of Syzygieae and Eucalypteae. Results are consistent and reproducible with both nuclear and organellar datasets. It confronts previous data about the deep nodes of Myrtaceae phylogeny.

Characterization of the complete chloroplast genome of Melaleuca cajuputi subsp. cumingiana (Myrtaceae)

Plants in the genus Melaleuca have been widely used as traditional medicine mainly because of their broad spectrum antimicrobial activity. In this study, we reported the complete chloroplast genome of Melaleuca cajuputi subsp. cumingiana. The chloroplast genome of this species is 158,855 bp in length, including a pair of inverted repeat regions (IRs) (26,727 bp) that is divided by a large single-copy (LSC) area (87,338 bp) and a small single-copy (SSC) area (18,063 bp). The circular chloroplast genome of M. cajuputi subsp. cumingiana contains 135 unique genes, composing of 87 protein-coding genes, 40 tRNA genes, and eight rRNA genes. Phylogenetic analysis indicates that M. cajuputi subsp. cumingiana was clustered with species in the tribe Melaleuceae. This complete chloroplast genome of M. cajuputi subsp. cumingiana will provide a powerful tool to accelerate breeding, biotechnological and phylogenetic study.