The complete chloroplast genome sequence ofAkebia trifoliataand a comparative analysis within the Ranales clade

Abstract

The complete nucleotide sequence of the Akebia trifoliata chloroplast (cp) genome was reported and characterized in this study. The cp genome is a closed circular molecule of 157 949 bp, composed of a pair of IR regions of 26 149 bp, one LSC region of 86 595 bp, and one SSC region of 19 056 bp. The GC contents of the LSC, SSC, IR regions, and the whole cp genome are 37.11%, 33.62%, 43.08% and 38.66%, respectively. The cp genome contains 130 predicted functional genes, including 85 PCGs, 37 tRNA and 8 rRNA genes. 168 SSRs and 23 long repeats were identified. The results revealed that 21 891 codons characterize the coding capacity of 85 protein-coding genes in Akebia trifoliata, 10.84% and 1.20% of the codons coded for leucine and cysteine respectively. The usage of the start codon exhibited no bias in the A. trifoliata cp genome. Phylogenetic analysis suggest that A. trifoliata is most closely related to S. japonica, which then formed a cluster with N. dormestica and M. saniculifolia to form subgroup of Ranunculales. Our study provides information on mangrove plant species in coastal intertidal zones.