Molecular characterization of root-knot nematodes (Meloidogyne spp.) from Arkansas, USA

Weimin Ye,Terry Kirkpatrick,Robert Thomas Robbins

doi:10.1038/s41598-019-52118-4

Weimin Ye, Terry Kirkpatrick + Show 1 more

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https://doi.org/10.1038/s41598-019-52118-4

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Abstract

Root-knot nematodes (Meloidogyne spp.) are the most common major pathogens of many crops throughout the world, impacting both the quantity and quality of marketable yields. In this study, a total of 244 root-knot nematode populations from various hosts from 39 counties in Arkansas were tested to determine the species diversity. Molecular characterization was performed on these populations by DNA sequencing of the ribosomal DNA 18S-ITS-5.8S, 28S D2/D3 and a mitochondrial DNA fragment flanking cytochrome oxidase gene subunit II - the intergenic spacer. Five species were identified, including M. incognita (Kofoid & White, 1919) Chitwood, 1949 from soybean, cotton, corn and various vegetables (232 samples); M. hapla Chitwood, 1949 from rose (1 sample); M. haplanaria Eisenback, Bernard, Starr, Lee & Tomaszewski, 2003 from okra, tomato, peanut, Indian hawthorn, ash, willow and elm trees (7 samples); M. marylandi Jepson & Golden in Jepson, 1987 from grasses (3 samples); and M. partityla Kleynhans, 1986 from pecan (1 sample) through a combined analysis of DNA sequencing and PCR by species-specific primers. Meloidogyne incognita is the most abundant species that was identified in 95% samples and was the only species in field crops including soybean and cotton, except for one population of M. haplanaria from soybean in Logan County (TK201). Species-specific primers were used to verify M. incognita through PCR by species-specific primers. Unlike historical data, M. arenaria, M. javanica and M. graminis were not detected from any of the samples collected during this study. This result is essential for effective and sustainable management strategies against root-knot nematodes in Arkansas.

Highlights

Root-knot nematodes (RKN) are microscopic worms that live in soil and feed on the roots of many crops and weeds
polymerase chain reaction (PCR) by species-specific primers is needed for the identification of M. incognita
One RKN population with the second-stage juveniles having very short tails was found in a sample collected at the Lon Mann Cotton Research Station near Brinkley, Arkansas

Summary

Introduction

Root-knot nematodes (RKN) are microscopic worms that live in soil and feed on the roots of many crops and weeds. RKN are the most widespread and serious plant-parasitic nematode pests, damaging a very wide range of crops throughout the world[1]. They are scientifically classified in the genus Meloidogyne (Tylenchida: Meloidogynidae) with over 100 species described[2]. Wehunt et al.[13] reported M. incognita, M. hapla, M. arenaria, M. graminis, and M. javanica from soybean fields near the Mississippi river. Walters and Barker[16] reported M. hapla, M. incognita, M. arenaria, and M. javanica (Treub, 1885) Chitwood, 1949 in Arkansas. In a recent survey from 106 soil and root samples, M. incognita, M. marylandi, M. haplanaria, M. hapla, M. arenaria and M. partityla Kleynhans, 1986 were identified through molecular diagnosis and M. incognita was the most abundant species[17]. The objective of this study was to collect RKN samples from field crops and natural sites in the state of Arkansas and to characterize the DNA sequences of RKN on the ribosomal DNA 18S-ITS-5.8S, 28S D2/D3 and mitochondrial DNA cytochrome oxidase gene subunit II-the intergenic spacer (CoxII-IGS) to determine the species and their distribution

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