Molecular and morphological characterization of fresh and 20-year-old fixed nematode specimens of Sauertylenchus maximus (Allen, 955) Siddiqi, 2000 from Arlington National Cemetery, Virginia, USA

Authors: KANTOR, MIHAIL - Orise Fellow; Vieira, Paulo; Skantar, Andrea; HUSE, GREGORY - Department Of Defense; Handoo, Zafar

Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/30/2022
Publication Date: 10/21/2022
Citation: Kantor, M.R., Reis Vieira, P.C., Skantar, A.M., Huse, G., Handoo, Z.A. 2022. Molecular and morphological characterization of fresh and 20-year-old fixed nematode specimens of Sauertylenchus maximus (Allen, 955) Siddiqi, 2000 from Arlington National Cemetery, Virginia, USA. Journal of Nematology. 54(1):Article 2022-0041. https://doi.org/10.2478/jofnem-2022-0041.
DOI: https://doi.org/10.2478/jofnem-2022-0041

Interpretive Summary: Plant-parasitic nematodes are microscopic worms that feed on plants and cause an estimated ten billion dollars of crop losses each year in the United States and 100 billion dollars globally. Stunt nematodes are one of the most economically important groups of plant-parasitic nematodes that cause crop losses to many important crops throughout the world. United States Department of Agriculture Nematode Collection (USDANC), was established in 1960 and is currently one of the largest nematode collections in the world. Nematode specimens deposited in the USDANC are routinely kept in a 3% formaldehyde and 2% glycerin solution. Formalin is known to damage DNA over time which makes it difficult to extract and use DNA from fixed specimens for molecular studies. In this study, anatomical and molecular traits were analyzed to identify a stunt nematode called Sauertylenchus maximus, isolated from Arlington National Cemetery, Virginia. This discovery is significant because it represents the first report of this nematode from Virginia and the first report of a successful DNA extraction from fixed nematode specimens deposited in the USDANC. This research will be of use to scientists, growers and extension agencies involved in nematode research and control.

Technical Abstract: Sauertylenchus maximus (Allen, 1955) Siddiqi, 2000 was discovered during a survey conducted at the Arlington National Cemetery, Virginia for the type specimens of Hoplolaimus galeatus. The senior author (ZH) had collected S. maximus from Arlington National Cemetery back in 2000 that were deposited in the United States Department of Agriculture Nematode Collection [(USDANC), unpublished data]. In this study we characterize the S. maximus fresh and fixed specimens from Arlington, VA by molecular and morphological means. Females and juveniles of S. maximus were recovered from the root and soil samples using the sugar centrifugal flotation. The fixed specimens used in this study were preserved in a 3% formaldehyde and 2% glycerin solution for over 20 years. Molecular analyses of fresh and fixed specimens included internal transcribed spacer (ITS) and 28S large subunit ribosomal DNA sequences, which indicated that the specimens recovered from the soil and roots were Sauertylenchus maximus. Morphology and morphometrics were consistent with the original and other description of this species. To our knowledge, this represents the first report of S. maximus from Virginia, U.S. and the first report of a successful DNA extraction from fixed nematode specimens deposited in the USDANC.