Morphological and molecular characterization of Paratylenchus beltsvilleiensis n.sp.(Tylenchida: Paratylenchidae) from the rhizosphere of pine tree (Pinus virginiana Mill) in Maryland, USA

Authors: MIHAIL, KANTOR - Orise Fellow; Handoo, Zafar; SUBBOTIN, SERGEI - California Department Of Food And Agriculture; Bauchan, Gary; Mowery, Joseph

Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/18/2021
Publication Date: 9/7/2021
Citation: Morphological and molecular characterization of Paratylenchus beltsvilleiensis n.sp.(Tylenchida: Paratylenchidae) from the rhizosphere of pine tree (Pinus virginiana Mill) in Maryland, USA. Journal of Nematology. 53(1). https://doi.org/10.21307/jofnem-2021-079.
DOI: https://doi.org/10.21307/jofnem-2021-079

Interpretive Summary: Plant-parasitic nematodes are microscopic worms that attack plant roots and cause an estimated ten billion dollars of crop loss each year in the United States and 100 billion dollars globally. Pin nematodes are an important problem damaging the roots of many kinds of plants worldwide. One problem with determining the extent of damage to crop plants is that the nematodes present in many areas are not known, such as in Maryland. This brief report describes how a team of ARS scientists together with California Department of Food & Agriculture, Sacramento, California, scientist identified from rhizospheric soil of a pine tree (Pinus virginiana) in Beltsville, Prince George’s County, Maryland, U.S.A, a new species of pin nematode using both morphological and molecular means. They also discovered how to distinguish the new species from closely related species with molecular and anatomical features including scanning electron microscopy (SEM), photographically and by line drawing images. This discovery is significant because new molecular and morphological information obtained from these species will facilitate future identifications of the pin nematodes. Therefore, this research will be used by scientists, growers, action agencies, and extension agencies involved in nematode research and control.

Technical Abstract: Paratylechus beltsvilleiensis n. sp. recovered from rhizospheric soil of a pine tree (Pinus virginiana) in Beltsville, Prince George’s County, Maryland, U.S.A., is described and illustrated along with photomicrographs and SEM images. A total number of twelve soil samples were collected in September and October of 2020, which revealed besides other nematodes a new species of the genus Paratylenchus. Females, males and juveniles of this new species were recovered from soil samples using the sugar centrifugal flotation and Baermann Funnel extraction methods. Morphologically, females are short, body length ranging from 245-267 µm, stylet 70 to 75 µm long with anchor shaped knobs, vulva located at 70-73% lacking vulval flap, spermatheca large, ovoid filled with sperms. Lateral field with three incisures of which the outer two are prominent. Tail slender, having a rounded tail terminus. Males, without stylet and have a degenerated pharynx, spicules measuring 17-20 µm and gubernaculum 5-5.5 µm. Both morphological observations and molecular analysis of ITS and partial 28S ribosomal RNA gene sequences indicated that the specimens recovered from the soil at Beltsville Park, Beltsville, MD, on Virginia pine represent a new pin nematode species.