Submission of barcode sequences of the European moth, Gymnancyla canella Denis and Schiffermüller (Pyralidae), a candidate biocontrol agent of the invasive Russian thistles, Salsola spp. (Chenopodiaceae) in California

Authors: BON, MARIE-CLAUDE - European Biological Control Laboratory (EBCL); DESURMONT, GAYLORD - European Biological Control Laboratory (EBCL); GUERMACHE, FATIHA - European Biological Control Laboratory (EBCL); Rector, Brian; Smith, Lincoln

Submitted to: National Center for Biotechnology Information (NCBI)
Publication Type: Database / Dataset
Publication Acceptance Date: 4/13/2023
Publication Date: 4/13/2023
Citation: Bon, M., Desurmont, G., Guermache, F., Rector, B.G., Smith, L. 2023. Submission of barcode sequences of the European moth, Gymnancyla canella Denis and Schiffermüller (Pyralidae), a candidate biocontrol agent of the invasive Russian thistles, Salsola spp. (Chenopodiaceae) in California. National Center for Biotechnology Information (NCBI). OQ801570.

Interpretive Summary: Russian thistles, Salsola spp. (Chenopodiaceae), are weeds native to central Asia that first appeared in North America in the 1870s. These weeds have become the most troublesome weeds in the western U.S. by invading about 100 million acres of lands and thus prompting a classical biological control program to search for potential biocontrol agents as early as in the 1990s. Among the candidate biocontrol agents, was included the European moth, Gymnancyla canella Denis and Schiffermüller (Pyralidae) of which the caterpillar feeds on developing seeds and young branch tips, causing extensive damage on Russian thistles. Experiments to test the strict specificity of this moth to the target weeds were conducted by a former USDA-ARS, European Biological Control Laboratory (EBCL) scientist, R. Sobhian, who demonstrated that the Mediterranean moth was specific enough to warrant further evaluation by the Albany ARS laboratory in California. Evaluations are expected to be finished by the ARS laboratory in another year. In support of these ongoing evaluations, nymphs of this moth were collected on Salsola sp. in 2023 by EBCL near Montpellier in southern France and introduced in the EBCL quarantine prior shipment to Albany quarantine. Typically, as part of shipping and quarantine regulatory frameworks, the moth must be correctly taxonomically identified. Analysis of DNA of the moth collected in 2023 with the historical DNAs of the moth collected on Salsola kali in Southern France and Turkey in the 1990s, identified by a taxonomist and preserved since then in the EBCL historical collection, confirmed that the contemporary collection belongs to Gymnancyla canella, hence preventing the risk of unintentional introductions of another species in quarantine testing and ultimately into the United States. The moths collected in 2023 were also genetically similar to the historical moths. The results of this study highlight the potential of mining historical collections in laboratories and museums as a source of DNA for accelerating comparative biological research, particularly when the populations of a given species are difficult to access or no longer exist in one geographic area.

Technical Abstract: Caterpillars of the European moth, Gymnancyla canella Denis and Schiffermüller (Lepidoptera: Pyralidae), feed on developing seeds and young branch tips of Russian thistles, Salsola spp. (Chenopodiaceae), causing extensive damage on these weeds. Within the framework of a classical biological control program to manage invasive Russian thistles in the western U.S., evaluation of Gymnancyla canella as a potential biocontrol agent of Russian thistles are being conducted by the Albany ARS laboratory in California. In order to conduct host specificity testing, nymphs of the moth were collected by EBCL in February 2023 on Salsola sp. near La Grande Motte, in southern France and introduced into EBCL quarantine prior their shipment to Albany ARS quarantine. Typically, as part of shipping and quarantine regulatory frameworks, a few specimens were tentatively assigned to a nominal species using the barcode region within the mitochondrial gene, Cox1. In the absence of barcode sequence records for Gymnancyla canella in GenBank, the Cox1 sequence obtained (GenBank accession no OQ801569) was compared to sequences generated from Gymnancyla canella voucher specimens collected in France (GenBank accession no OQ801570) and in Turkey (GenBank accession no OQ801571), dating back to the 1990s and archived since then in the EBCL insect collection. The Cox1 sequence of the modern Gymnancyla canella was identical to the one obtained from Gymnancyla canella in Turkey (Yarimca near Afyonkarahisar), but one substitution different from Gymnancyla canella in France (Carnon). The present study has not only confirmed that the barcoding approach could be decisive in the species identification of the insects prior their shipment to USA when voucher specimens are available and taxonomists lacking, but also underlined the importance of historical specimens for contemporary biological control programs. The development of efficient DNA extraction method of obtaining historical genomic data without damaging source material, and of improved PCR performance mainly due to a new generation of polymerase enzymes has created new opportunities for historical collections, including those maintained by biological control practitioners.