A DNA barcode for land plants

TLDR

DNA barcoding uses a standard DNA region to identify species, but no consensus exists on which region(s) to use for land plants. The study aims to recommend a standard plant barcode by comparing seven leading plastid DNA regions. We compared the performance of seven candidate plastid DNA regions (atpF‑atpH spacer, matK gene, rbcL gene, rpoB gene, rpoC1 gene, psbK‑psbI spacer, and trnH‑psbA spacer). We recommend the two‑locus combination rbcL+matK as the plant barcode, providing a universal framework for routine specimen identification and aiding the discovery of overlooked land plant species.

Abstract

DNA barcoding involves sequencing a standard region of DNA as a tool for species identification. However, there has been no agreement on which region(s) should be used for barcoding land plants. To provide a community recommendation on a standard plant barcode, we have compared the performance of 7 leading candidate plastid DNA regions (atpF-atpH spacer, matK gene, rbcL gene, rpoB gene, rpoC1 gene, psbK-psbI spacer, and trnH-psbA spacer). Based on assessments of recoverability, sequence quality, and levels of species discrimination, we recommend the 2-locus combination of rbcL+matK as the plant barcode. This core 2-locus barcode will provide a universal framework for the routine use of DNA sequence data to identify specimens and contribute toward the discovery of overlooked species of land plants.