<abstract xmlns="http://www.w3.org/1999/xhtml"><p>Difficulties inherent in the morphological identification of cyst nematodes of the genus <italic>Heterodera</italic> Schmidt, 1871, an important lineage of plant parasites, has led to broad adoption of molecular methods for diagnosing and differentiating species. The pool of publicly available sequence data has grown significantly over the past few decades, and over half of all known species of <italic>Heterodera</italic> have been characterized using one or more molecular markers commonly employed in DNA barcoding (18S, internal transcribed spacer [ITS], 28S, <italic>coxI</italic>). But how reliable are these data and how useful are these four markers for differentiating species? We downloaded all 18S, ITS, 28S, and <italic>coxI</italic> gene sequences available on the National Center for Biotechnology Information (NCBI) database, GenBank, for all species of <italic>Heterodera</italic> for which data were available. Using a combination of sequence comparison and tree-based phylogenetic methods, we evaluated this dataset for erroneous or otherwise problematic sequences and examined the utility of each molecular marker for the delineation of species. Although we find the rate of obviously erroneous sequences to be low, all four molecular markers failed to differentiate between at least one species pair. Our results suggest that while a combination of multiple markers is best for species identification, the <italic>coxI</italic> marker shows the most utility for species differentiation and should be favored over 18S, ITS, and 28S, where resources are limited. Presently, less than half the valid species of <italic>Heterodera</italic> have a sequence of <italic>coxI</italic> available, and only a third have more than one sequence of this marker.</p></abstract>

Difficulties inherent in the morphological identification of cyst nematodes of the genus Heterodera Schmidt, 1871, an important lineage of plant parasites, has led to broad adoption of molecular methods for diagnosing and differentiating species. The pool of publicly available sequence data has grown significantly over the past few decades, and over half of all known species of Heterodera have been characterized using one or more molecular markers commonly employed in DNA barcoding (18S, internal transcribed spacer [ITS], 28S, coxI). But how reliable are these data and how useful are these four markers for differentiating species? We downloaded all 18S, ITS, 28S, and coxI gene sequences available on the National Center for Biotechnology Information (NCBI) database, GenBank, for all species of Heterodera for which data were available. Using a combination of sequence comparison and tree-based phylogenetic methods, we evaluated this dataset for erroneous or otherwise problematic sequences and examined the utility of each molecular marker for the delineation of species. Although we find the rate of obviously erroneous sequences to be low, all four molecular markers failed to differentiate between at least one species pair. Our results suggest that while a combination of multiple markers is best for species identification, the coxI marker shows the most utility for species differentiation and should be favored over 18S, ITS, and 28S, where resources are limited. Presently, less than half the valid species of Heterodera have a sequence of coxI available, and only a third have more than one sequence of this marker.

Reliability and Utility of Standard Gene Sequence Barcodes for the Identification and Differentiation of Cyst Nematodes of the Genus <italic>Heterodera</italic>

Australian National Insect Collection, National Research Collections Australia, CSIRO

Journal of Nematology

This work is licensed under the Creative Commons Attribution 4.0 International License.

Reliability and Utility of Standard Gene Sequence Barcodes for the Identification and Differentiation of Cyst Nematodes of the Genus 

Difficulties inherent in the morphological identification of cyst nematodes of the genus Heterodera Schmidt, 1871, an important lineage of plant parasites, has...

Reliability and Utility of Standard Gene Sequence Barcodes for the Identification and Differentiation of Cyst Nematodes of the Genus Heterodera

Article Category: Research Paper

Published Online: Jul 29, 2022

Page range: -

Received: Dec 13, 2021

DOI: https://doi.org/10.2478/jofnem-2022-0024

Keywords
detection, diagnosis, genetics, molecular biology, systematics, taxonomy

© 2022 Huston et al. published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Reliability and Utility of Standard Gene Sequence Barcodes for the Identification and Differentiation of Cyst Nematodes of the Genus Heterodera

Article Category: Research Paper

Published Online: Jul 29, 2022

Page range: -

Received: Dec 13, 2021

DOI: https://doi.org/10.2478/jofnem-2022-0024

Keywordsdetection, diagnosis, genetics, molecular biology, systematics, taxonomy

© 2022 Huston et al. published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Keywords
detection, diagnosis, genetics, molecular biology, systematics, taxonomy