Abstract
Neolamarckia cadamba is an important tropical and subtropical tree for timber industry in southern China and is also a medicinal plant because of the secondary product cadambine. N. cadamba belongs to Rubiaceae family and its taxonomic relationships with other species are not fully evaluated based on genome sequences. Here, we report the complete sequences of mitochondrial genome of N. cadamba, which is 414,980 bp in length and successfully assembled in two genome circles (109,836 bp and 305,144 bp). The mtDNA harbors 83 genes in total, including 40 protein-coding genes (PCGs), 31 transfer RNA genes, 6 ribosomal RNA genes, and 6 other genes. The base composition of the whole genome is estimated as 27.26% for base A, 22.63% for C, 22.53% for G, and 27.56% for T, with the A + T content of 54.82% (54.45% in the small circle and 54.79% in the large circle). Repetitive sequences account for ~ 0.14% of the whole genome. A maximum likelihood (ML) tree based on DNA sequences of 24 PCGs supports that N. cadamba belongs to order Gentianales. A ML tree based on rps3 gene of 60 species in family Rubiaceae shows that N. cadamba is more related to Cephalanthus accidentalis and Hymenodictyon parvifolium and belongs to the Cinchonoideae subfamily. The result indicates that N. cadamba is genetically distant from the species and genera of Rubiaceae in systematic position. As the first sequence of mitochondrial genome of N. cadamba, it will provide a useful resource to investigate genetic variation and develop molecular markers for genetic breeding in the future.
Highlights
Neolamarckia cadamba is an important tropical and subtropical tree for timber industry in southern China and is a medicinal plant because of the secondary product cadambine
Few studies with molecular markers have been reported on population genetic structure, phylogeography and molecular s ystematics[27]
Based on the mitochondrial DNA (mtDNA) sequence, we evaluated the phylogenetic relationships among families and genera of Rubiaceae to gain insights into the taxonomic position of N. cadamba
Summary
Neolamarckia cadamba is an important tropical and subtropical tree for timber industry in southern China and is a medicinal plant because of the secondary product cadambine. The well-known features of mitochondrial DNA (mtDNA) in plants include (i) maternal inheritance in angiosperms, (ii) haplotype per cell, (iii) intra-molecular recombination between repeats[28], and (iv) the number of females as its population size (Nf). These features differ from those of nuclear genomes, which correspondingly exhibits (i) biparental inheritance, (ii) diploid per cell, (iii) interchromosome recombination and relatively high mutation rates, and (iv) large effective population sizes (2Ne) of nuclear genes ( 2Ne = 4Nf under 1:1 sexual ratio)[29]. MtDNA sequences are useful for studying the long-term phylogenetic relationships at the level of species or higher order, and for studying other perspectives of evolutionary relationships, such as lineage sorting, hybridization and cytonuclear interactions[31]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
