The Complete Plastid Genome Sequences of the Belian (Eusideroxylon zwageri): Comparative Analysis and Phylogenetic Relationships with Other Magnoliids

Abstract

The Belian (Eusideroxylon zwageri Teijsm. & Binn.) is a commercially important timber species in Southeast Asia that was listed on the IUCN Red List of threatened species in 1998. Six years ago, we published an article in Genome Biology Ecology entitled “Evolutionary Comparisons of the Chloroplast Genome in Lauraceae and Insights into Loss Events in the Magnoliids” in which one complete plastid genome of Belian was assembled for comparative analyses of the plastomes in Lauraceae. However, a recent study concluded that our sequenced Belian individual can be located in the clade of Myristicaceae instead of that of Lauraceae. Here, we performed reanalyses of an additional two Belian plastomes, along with 42 plastomes from plants spanning 10 families of the Magnoliids. The three Belian plastomes are 39% CG and vary in length from 157,535 to 157,577 bp. A total of 37 tRNA genes, 8 rRNA genes, and 85 protein-coding genes were among the 130 annotated genes. There were 95–101 repeat sequences and 56–61 simple repeat sequences (SSRs). Comparative genomic analysis revealed 170 mutation sites in their plastomes, which include 111 substitutions, 53 indels, and 6 microinversions. Phylogeny was reconstructed using maximum-likelihood and Bayesian approaches for 44 magnoliids species, indicating that the 3 Belian individuals were nested among the species in the Lauraceae family rather than Myristicaceae.