Morphological and Molecular Characterization of Pratylenchus dakotaensis n. sp. (Nematoda: Pratylenchidae), a New Root-Lesion Nematode Species on Soybean in North Dakota, USA.

Danqiong Huang,Guiping Yan,Zafar A Handoo,Gary R Bauchan,Intiaz A Chowdhury,Joseph D Mowery,Mihail R Kantor,Addison Plaisance

doi:10.3390/plants10010168

Danqiong Huang, Guiping Yan + Show 6 more

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https://doi.org/10.3390/plants10010168

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Abstract

Root-lesion nematodes (Pratylenchus spp.) of the genus Pratylenchus Filipjev, 1936, are among the most important nematode pests on soybean (Glycine max (L.) Merr.), along with soybean cyst and root-knot nematodes. In May 2015 and 2016, a total of six soil samples were collected from a soybean field in Walcott, Richland County, ND and submitted to the Mycology and Nematology Genetic Diversity and Biology Laboratory (MNGDBL), USDA, ARS, MD for analysis. Later, in 2019, additional nematodes recovered from a greenhouse culture on soybean originally from the same field were submitted for further analysis. Males, females, and juveniles of Pratylenchus sp. were recovered from soil and root samples and were examined morphologically and molecularly. DNA from single nematodes were extracted, and the nucleotides feature of three genomic regions targeting on the D2–D3 region of 28S rDNA and ITS rDNA and mitochondrial cytochrome oxidase subunit I (COX1) gene were characterized. Phylogeny trees were constructed to ascertain the relationships with other Pratylenchus spp., and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was performed to provide a rapid and reliable differentiation from other common Pratylenchus spp. Molecular features indicated that it is a new, unnamed Pratylenchus sp. that is different from morphologically closely related Pratylenchus spp., including P. convallariae, P. pratensis, P. fallax, and P. flakkensis. In conclusion, both morphological and molecular observations indicate that the North Dakota isolate on soybean represents a new root-lesion nematode species which is named and described herein as Pratylenchus dakotaensis n. sp.

Highlights

The genus Pratylenchus Filipjev, 1936, is one of the most important nematode genera in terms of the economic impact they have on crops [1,2]
Additional nematodes recovered from the greenhouse culture on soybean were submitted to the MNGDBL, Beltsville, MD
Based on the molecular results obtained using the 28S D2–D3 primers, the North DaBased on the molecular results obtained using the 28S D2–D3 primers, the North kota population had less than 94.2% similarity with morphologically closely related

Summary

Introduction

The genus Pratylenchus Filipjev, 1936, is one of the most important nematode genera in terms of the economic impact they have on crops [1,2]. The root-lesion nematodes are ranked as the third most important group of plant-parasitic nematodes after root-knot and cyst nematodes [2] in terms of economic loss in agriculture and horticulture. Frederick and Tarjan [6] published a compendium of the Pratylenchus genus in 1989 in which they reported 89 species. In 1989, Handoo and Golden [7] published a key and compendium to 63 valid species, including an update of the work done by different workers on the genus. The plants reported as hosts for the genus are very large. One species, Pratylenchus penetrans, has been reported to have more than 400 plants as hosts [8]

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