Biology subjects

Kiewnick, S.

Publications and source records attributed to Kiewnick, S..

3 recordsLinked to original sources

bioRxiv2025

Globodera pallida virulence on major potato resistance has a common genetic basis across Western Europe

The potato cyst nematode Globodera pallida poses a major threat to potato production in Western Europe. Current management strategies largely depend on the use of potato varieties carrying the genetic resistance GpaVvrn. However, reports from multiple West-European countries indicate a steady rise in virulence against GpaVvrn-containing potato varieties, raising serious concerns about G. pallida control. Although recent studies have resolved the genetic basis of virulence in two Dutch G. pallida populations, it remains unclear how conserved this genetic adaptation is in populations from different regions. To investigate this, we first selected eight Dutch G. pallida populations on the GpaVvrn-containing potato variety Seresta and confirmed a previously identified virulence locus. Second, by analysing the allele frequencies of four virulence-associated SNPs in Dutch, British, and French GpaVvrn-selected G. pallida populations, we found that the same allele is consistently selected by GpaVvrn across Western Europe. Third, we analysed the propagation of eight G. pallida populations on 26 GpaVvrn-containing potato varieties and showed that a populations allele frequency of a single SNP (T173N) accurately reflects its reproduction on GpaVvrn. Fourth, we developed an allele-specific quantitative PCR (AS-qPCR) assay to determine a populations alternative allele frequency (AAF) of T173N and showed that AS-qPCR-based AAFs reliably indicate virulence levels on GpaVvrn in Dutch and German G. pallida populations. Together, these findings suggest that a common allele is consistently selected by GpaVvrn in populations from different regions across Western Europe. The AS-qPCR assay developed in this study provides a practical tool to estimate G. pallida virulence on GpaVvrn in the field, enabling field-tailored and sustainable resistance management strategies for farmers.

genetics↗

bioRxiv2024

Unveiling the genome assembly of the polyploid and quarantine root-knot nematode, Meloidogyne enterolobii

Root-knot nematodes of the genus Meloidogyne are obligatory plant endoparasites that cause substantial economic losses to the agricultural production and impact the global food supply. These plant parasitic nematodes belong to the most widespread and devastating genus worldwide, yet few measures of control are available. The most efficient way to control root-knot nematodes (RKN) is deployment of resistance genes in plants. However, current resistance genes that control other Meloidogyne species are mostly inefficient on M. enterolobii. Consequently, M. enterolobii was listed as a European Union quarantine pest implementing regulation. To gain insight into the molecular characteristics underlying its parasitic success, exploring the genome of M. enterolobii is essential. Here, we report a high-quality genome assembly of Meloidogyne enterolobii using the high-fidelity long-read sequencing technology developed by Pacific Biosciences, combined with a gap-aware sequence transformer, DeepConsensus. The resulting genome assembly spans 273 Mbp with 556 contigs, a GC% of 30 {+/-} 0.042 and an N50 value of 2.11Mb, constituting a useful platform for comparative, population and functional genomics.

genomics↗

bioRxiv2019

The polyploid genome of the mitotic parthenogenetic root knot nematode Meloidogyne enterolobii

Root-knot nematodes (genus Meloidogyne) are plant parasitic species that cause huge economic loss in the agricultural industry and affect the prosperity of communities in developing countries. Control methods against these plant pests are sparse and the current preferred method is deployment of plant cultivars bearing resistance genes against Meloidogyne species. However, some species such as M. enterolobii are not controlled by the resistance genes deployed in the most important crop plants cultivated in Europe. The recent identification of this species in Europe is thus a major concern. Like the other most damaging Meloidogyne species (e.g. M. incognita, M. arenaria and M. javanica), M. enterolobii reproduces by obligatory mitotic parthenogenesis. Genomic singularities such as a duplicated genome structure and a relatively high proportion of transposable elements have previously been described in the above mentioned mitotic parthenogenetic Meloidogyne.\n\nTo gain a better understanding of the genomic and evolutionary background we sequenced the genome of M. enterolobii using high coverage short and long read technologies. The information contained in the long reads helped produce a highly contiguous genome assembly of M. enterolobii, thus enabling us to perform high quality annotations of coding and non-coding genes, and transposable elements.\n\nThe genome assembly and annotation reveals a genome structure similar to the ones described in the other mitotic parthenogenetic Meloidogyne, described as recent hybrids. Most of the genome is present in 3 different copies that show high divergence. Because most of the genes belong to these duplicated regions only few gene losses took place, which suggest a recent polyploidization. The most likely hypothesis to reconcile high divergence between genome copies despite few gene losses and translocations is also a recent hybrid origin. Consistent with this hypothesis, we found an abundance of transposable elements at least as high as the one observed in the mitotic parthenogenetic nematodes M. incognita and M. javanica.

genomics↗