SNP markers tightly linked to root knot nematode resistance in grapevine (Vitis cinerea) identified by a genotyping-by-sequencing approach followed by Sequenom MassARRAY validation.

Harley M Smith,Peter R Clingeleffer,Mark R Thomas,Norma B Morales,Sam Moskwa,Brady P Smith

doi:10.1371/journal.pone.0193121

Harley M Smith, Peter R Clingeleffer + Show 4 more

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https://doi.org/10.1371/journal.pone.0193121

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Abstract

Plant parasitic nematodes, including root knot nematode Meloidogyne species, cause extensive damage to agriculture and horticultural crops. As Vitis vinifera cultivars are susceptible to root knot nematode parasitism, rootstocks resistant to these soil pests provide a sustainable approach to maintain grapevine production. Currently, most of the commercially available root knot nematode resistant rootstocks are highly vigorous and take up excess potassium, which reduces wine quality. As a result, there is a pressing need to breed new root knot nematode resistant rootstocks, which have no impact on wine quality. To develop molecular markers that predict root knot nematode resistance for marker assisted breeding, a genetic approach was employed to identify a root knot nematode resistance locus in grapevine. To this end, a Meloidogyne javanica resistant Vitis cinerea accession was crossed to a susceptible Vitis vinifera cultivar Riesling and results from screening the F1 individuals support a model that root knot nematode resistance, is conferred by a single dominant allele, referred as MELOIDOGYNE JAVANICA RESISTANCE1 (MJR1). Further, MJR1 resistance appears to be mediated by a hypersensitive response that occurs in the root apical meristem. Single nucleotide polymorphisms (SNPs) were identified using genotyping-by-sequencing and results from association and genetic mapping identified the MJR1 locus, which is located on chromosome 18 in the Vitis cinerea accession. Validation of the SNPs linked to the MJR1 locus using a Sequenom MassARRAY platform found that only 50% could be validated. The validated SNPs that flank and co-segregate with the MJR1 locus can be used for marker-assisted selection for Meloidogyne javanica resistance in grapevine.

Highlights

Plant parasitic nematodes are major soil-borne pests that cause extensive damage to a wide range of crops with an estimated cost of $80 billion (USD) per year [1]
Three propagated cuttings from V. cinerea C2-50, an accession in the CSIRO Rootstock Collection, were screened for root knot nematode resistance and results showed that M. javanica ‘pt 1103P’ failed to parasitize this accession, as no egg mass development occurred on the roots for each of the replicated cuttings (Table 1)
For the remaining 51 F1 individuals screened for M. javanica ‘pt. 1103P’ resistance, no egg masses or galls were detected on the roots in all three replicates

Summary

Introduction

Plant parasitic nematodes are major soil-borne pests that cause extensive damage to a wide range of crops with an estimated cost of $80 billion (USD) per year [1]. Root knot nematodes are sedentary endoparasites that cause extensive damage to a wide range of crop species including V. vinifera [3,4,5]. Root knot nematodes are typically found in sandy soils, and complete their life cycle by parasitizing roots of susceptible plants. The life cycle of the root knot nematode begins after the eggs hatch and release the free-living juvenile nematodes, which migrate through the soil. The nematode develops into an egg-laying female and the life cycle is completed [3,4,5]

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