Journal Article

Complete plastome sequencing resolves taxonomic relationships among species of Calligonum L. (Polygonaceae) in China

Li, Ting, Burgess, Kevin S., Song, Feng, Ge, Xue-Jun, Feng, Ying

2020

Overview

Background Calligonum (Polygonaceae) is distributed from southern Europe through northern Africa to central Asia, and is typically found in arid, desert regions. Previous studies have revealed that standard DNA barcodes fail to discriminate Calligonum species. In this study, the complete plastid genomes (plastome) for 32 accessions of 21 Calligonum species is sequenced to not only generate the first complete plastome sequence for the genus Calligonum but to also 1) Assess the ability of the complete plastome sequence to discern species within the group, and 2) screen the plastome sequence for a cost-effective DNA barcode that can be used in future studies to resolve taxonomic relationships within the group. Results The whole plastomes of Calligonum species possess a typical quadripartite structure. The size of the Calligonum plastome is approximately 161 kilobase pairs (kbp), and encodes 113 genes, including 79 protein-coding genes, 30 tRNA genes, and four rRNA genes. Based on ML phylogenetic tree analyses, the complete plastome has higher species identification (78%) than combinations of standard DNA barcodes ( rbcL  +  matK  + nrITS, 56%). Five newly screened gene regions ( ndhF , trnS-G , trnC-petN , ndhF-rpl32 , rpl32-trnL ) had high species resolution, where ndhF and trnS - G were able to distinguish the highest proportion of Calligonum species (56%). Conclusions The entire plastid genome was the most effective barcode for the genus Calligonum , although other gene regions showed great potential as taxon-specific barcodes for species identification in Calligonum .

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: Agriculture / Analysis / Arid regions / Bar codes / Biomedical and Life Sciences / Calligonum / Central Asia / China / cost effectiveness / Deoxyribonucleic acid / Deserts / DNA / DNA barcodes / DNA barcoding / DNA Barcoding, Taxonomic - methods / Gene sequencing / Genes / Genes, Plant - genetics / Genome, Plant - genetics / Genomes / Genomics / Genomics and evolution / Identification / Life Sciences / Morphology / Northern Africa / Nucleotide sequence / Phylogenetics / Phylogeny / Plant Sciences / Plastid genome / Plastids - genetics / Plastomes / Polygonaceae / Polygonaceae - classification / Polygonaceae - genetics / Proteins / Ratios / Research Article / rRNA / Sequence Analysis, DNA / Southern European region / Species / species identification / Species resolution / Taxonomy / Transfer RNA / Tree Biology / tRNA