Toward phylogenomics of Lauraceae: The complete chloroplast genome sequence of Litsea glutinosa (Lauraceae), an invasive tree species on Indian and Pacific Ocean islands

Litsea glutinosa (Lour.) C.B.Rob. is a native species from Indo-Malesia and China. Due to its invasive behaviour on Indian and Pacific Ocean islands, a better understanding of L. glutinosa is becoming increasingly urgent to improve management practices and our understanding of its dispersal ability throughout its native range. Indeed, knowledge on the distribution of genetic diversity in native populations is crucial to understand the factors that drive the invasive character of L. glutinosa. Here we assemble and analyze its complete chloroplast genome sequence, the first in the genus Litsea. The total genome size was 152,618 bp in length, containing a pair of inverted repeats (IRs) of 20,063 bp, which were separated by a large single copy (LSC) and small single copy (SSC) of 93,690 bp and 18,802 bp, respectively. The overall GC content of the plastid genome was 39.2%. 127 genes were annotated, including 83 protein-coding genes, 36 tRNA genes and 8 rRNA genes. In these genes, eighteen contained one or two introns. Nine repeated sequences (5 palindromic and 4 forward) and 56 simple sequence repeats were identified in the plastid genome of L. glutinosa. Comparing our sequence with available complete chloroplast genomes in Lauraceae, five intergenic spacers (including trnH-psbA and rpl32-trnL) and one intron showed promising levels of variations for application in DNA-barcoding or intrageneric studies. In addition, phylogenetic analysis of complete Magnoliid plastid genomes highlighted affinities between Litsea and Cinnamomum. These results are expected to be useful to both our understanding of the characteristics and evolution of the invasive behaviour, as well as to efficiently manage these pest species in their introduced areas.