Abstract Detail

Biodiversity Informatics & Herbarium Digitization

Braukmann, Thomas [1], Kuzmina, Maria [1], Steinke, Dirk [1], Zakharov, Evgeny [1], Hebert, Paul [1].

Building the DNA barcode library for the flora of Canada using herbarium specimens.

Because herbaria are a valuable source of voucher specimens, they are often used to construct the DNA barcode libraries that are essential for plant identifications and metabarcoding studies. We sequenced at least one of the barcode regions (rbcL, matK, or ITS) for 20,816 specimens representing 5,076 of the 5,190 vascular plant species in Canada (98%). We used beta regression to evaluate the effects of age, type of preservation, and taxonomic affiliation (family) on sequence recovery. We also tested the ability of these DNA barcodes to discriminate the species in local floras across Canada using simulated assemblages from the plant lists of 27 national parks. The capacity of each barcode region to determine the correct species assignment was estimated using BLAST and mothur. Mean pairwise distance and mean nearest taxon distance were strong predictors of barcode performance for different plant families and genera. All three markers delivered correct generic assignments with high accuracy (91-98%), but species discrimination ranged from 81% (matK) to 44% (rbcL).  Despite the low number of plant taxa in the arctic, DNA barcodes had the least success in this biogeographic region with species resolution ranging from 36% with rbcL to 69% with matK. By contrast, species resolution peaked in the Woodland region at 87% for matK. Specimen age and method of preservation had significant effects on sequence recovery for all markers with differential impacts among vascular plant families. In addition to the standard DNA barcodes, high-throughput sequencing approaches can recover long amplicons with high fidelity. To improve taxonomic resolution, we sequenced the full ITS region from diverse species of angiosperms on the SEQUEL platform. This approach reduces the cost and improves the quality of DNA barcode reference libraries using herbarium specimens. Our results indicate that DNA barcoding is very effective in identifying plants to genus and that it performs well in discriminating species in regions where floristic diversity is highest. The DNA barcode library for the vascular plants of Canada represents a key resource for metabarcoding and ecological genetic research.

1 - University of Guelph, Centre for Biodiversity Genomics, 50 Stone Rd E, Guelph, ON, N1G2W1, Canada

DNA barcoding
taxonomic resolution

Presentation Type: Oral Paper
Abstract ID:399
Candidate for Awards:None

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