Biology subjects

Goverse, A.

Publications and source records attributed to Goverse, A..

11 recordsLinked to original sources

bioRxiv2025

Plant parasitic cyst nematodes respond to viral infection through RNA interference

Plant-parasitic nematodes (PPN) cause yield losses to multiple important crop species and counteractive measures are only partially successful. Recently the first viruses that infect PPN were discovered, presenting new research opportunities to understand and halt PPN. A critical step in this process is to identify how PPN respond to viruses. Here, two PPN species, the potato cyst nematode Globodera rostochiensis and the beet cyst nematode Heterodera schachtii, were used to study PPN-virus interactions. Viral discovery based on bioinformatic analyses indicated three putative viral genomes present in G. rostochiensis (a Toti-like, Xinzhou-like, and Picorna-like virus) and five putative viral genomes in H. schachtii (a Bunya-like, Tobamo-like, Picorna-like, and two Nyami-like viruses). A genome composition analysis and RT-PCR data confirmed that these viruses infect the nematodes and not their host plants. Subsequently, antiviral RNAi activity was detected in both H. schachtii and G. rostochiensis using small RNA sequencing. For G. rostochiensis two distinct genotypes were investigated. These strongly differed in their RNAi response: Ro5-line 22 produced roughly 40 times more antiviral viRNAs than Ro1-line 19. Our measurement of an active antiviral response represents the first indication of antiviral activity in PPN. Author summaryPlant-parasitic nematodes (PPN) are key agricultural pests and although some PPN viruses have been discovered recently, it is still unknown if and how PPN respond to viral infection. Here we find three viruses in the potato cyst nematode (Globodera rostochiensis) and five viruses in the beet cyst nematode (Heterodera schachtii). Of these viruses, six are newly discovered. Genome and molecular analyses confirm that all found viruses specifically infect nematodes and not their host plants. By measuring small RNA profiles, it was confirmed that PPN react to viral infection by means of RNAi, except for a weak response against two negatively stranded Nyami-like viruses. Moreover, distinct RNAi profiles were found for two potato cyst nematode lines, giving the first insight into which genes might be involved in RNAi in PPN. Together, this research provides the first proof of an active antiviral response in PPN. Thereby this finding opens new opportunities for biological control and gene editing tools.

molecular biology↗

bioRxiv2023

WOX11-mediated cell size control in Arabidopsis attenuates fecundity of endoparasitic cyst nematodes

O_LICyst nematodes establish permanent feeding structures called syncytia inside host root vasculature, disrupting the flow of water and minerals. In response, plants form WOX11-mediated adventitious lateral roots at nematode infection sites. WOX11-adventitious lateral rooting modulates tolerance to nematode infections, however, whether this also benefits nematode parasitism remains unknown. C_LIO_LIHere, we report on bioassays using a 35S::WOX11-SRDX transcriptional repressor mutant to investigate whether WOX11-adventitious lateral rooting promotes syncytium development and thereby female fecundity. Moreover, we chemically inhibited cellulose biosynthesis to verify if WOX11 directly modulates cell wall plasticity in syncytia. Finally, we performed histochemical analyses to test if WOX11 mediates syncytial cell wall plasticity via reactive oxygen species (ROS). C_LIO_LIRepression of WOX11-mediated transcription specifically enhanced the radial expansion of syncytial elements, increasing both syncytium size and female offspring. The enhanced syncytial hypertrophy observed in the 35S::WOX11-SRDX mutant could be phenocopied by chemical inhibition of cellulose biosynthesis and was associated with elevated levels of ROS at nematode infection sites. C_LIO_LIWe therefore conclude that WOX11 restricts radial expansion of nematode feeding structures and female fecundity, likely by modulating ROS-mediated cell wall plasticity mechanisms. Remarkably, this novel role of WOX11 in plant cell size control is independent of WOX11-adventitious rooting underlying disease tolerance. C_LI

plant biology↗

bioRxiv2023

WOX11-mediated adventitious lateral root formation modulates tolerance of Arabidopsis to cyst nematode infections

The transcription factor WUSCHEL-RELATED HOMEOBOX 11 (WOX11) in Arabidopsis initiates the formation of adventitious lateral roots upon mechanical injury in primary roots. Root-invading nematodes also induce de novo root organogenesis leading to excessive root branching, but it is not known if this symptom of disease involves mediation by WOX11 and if it benefits the plant. Here, we show with targeted transcriptional repression and reporter gene analyses in Arabidopsis that the beet cyst nematode Heterodera schachtii activates WOX11-adventitious lateral rooting from primary roots close to infection sites. The activation of WOX11 in nematode-infected roots occurs downstream of jasmonic acid-dependent damage signaling via ETHYLENE RESPONSIVE FACTOR109, linking adventitious lateral root formation to nematode damage to host tissues. By measuring different root system components, we found that WOX11-mediated formation of adventitious lateral roots compensates for nematode-induced inhibition of primary root growth. Our observations further demonstrate that WOX11-mediated rooting reduces the impact of nematode infections on aboveground plant development and growth. Altogether, we conclude that the transcriptional regulation by WOX11 modulates root system plasticity under biotic stress, which is one of the key mechanisms underlying tolerance of Arabidopsis to cyst nematode infections.

plant biology↗

bioRxiv2023

From root to shoot; Quantifying nematode tolerance in Arabidopsis thaliana by high-throughput phenotyping of plant development

Nematode migration, feeding site formation, withdrawal of plant assimilates, and activation of plant defence responses have a significant impact on plant growth and development. Plants display intraspecific variation in tolerance limits for root-feeding nematodes. Although disease tolerance has been recognised as a distinct trait in biotic interactions of mainly crops, we lack mechanistic insights. Progress is hampered by difficulties in quantification and laborious screening methods. We turned to the model plant Arabidopsis thaliana, since it offers extensive resources to study the molecular and cellular mechanisms underlying nematode-plant interactions. Through imaging of tolerance-related parameters the green canopy area was identified as an accessible and robust measure for assessing damage due to cyst nematode infection. Subsequently, a high-throughput phenotyping platform simultaneously measuring the green canopy area growth of 960 A. thaliana plants was developed. This platform can accurately measure cyst- and root-knot nematode tolerance limits in A. thaliana through classical modelling of tolerance limits. Furthermore, real-time monitoring provided data for a novel view of tolerance, identifying a compensatory growth response. These findings show that our phenotyping platform will enable further studies into a mechanistic understanding of tolerance to below-ground biotic stress. HighlightThe mechanisms of tolerance to root-parasitic nematodes remain unknown. We developed a high-throughput phenotyping system that enables unravelling the underlying mechanisms of tolerance to nematodes.

plant biology↗

bioRxiv2022

Root architecture plasticity in response to endoparasitic cyst nematodes is mediated by damage signaling

O_LIPlant root architecture plasticity in response to biotic stresses has not been thoroughly investigated. Infection by the endoparasitic cyst nematodes induces root architectural changes that involve the formation of secondary roots at infection sites. However, the molecular mechanisms regulating secondary root formation in response to cyst nematode infection remain largely unknown. C_LIO_LIWe first assessed whether secondary roots form in a nematode-density dependent manner by challenging wild type Arabidopsis plants with increasing numbers of cyst nematodes (Heterodera schachtii). Next, by using jasmonate-related reporter lines and knock-out mutants, we tested if tissue damage by nematodes triggers secondary root formation. Finally, we verified whether damage-induced secondary root formation depends on local auxin biosynthesis at nematode infection sites. C_LIO_LIIntracellular host invasion by H. schachtii triggers a transient local increase in jasmonates, which activates the expression of ERF109 in a COI1-dependent manner. Knock-out mutations in COI1 and ERF109 disrupt the nematode-density dependent increase of secondary roots observed in wildtype plants. Furthermore, ERF109 regulates secondary root formation upon H. schachtii infection via local auxin biosynthesis. C_LIO_LIHost invasion by H. schachtii triggers secondary root formation via the damage-induced jasmonate-dependent ERF109 pathway. This points at a novel mechanism underlying plant root plasticity in response to biotic stress. C_LI

plant biology↗

bioRxiv2021

Comparative genomics among three cyst nematode species reveals distinct evolutionary histories among effector families and an irregular distribution of effector-associated promoter motifs

Potato cyst nematodes (PCNs), an umbrella term used for two species, Globodera pallida and G. rostochiensis, belong worldwide to the most harmful pathogens of potato. Pathotype-specific host plant resistances are an essential handle for PCN control. However, the poor delineation of G. pallida pathotypes hampers the efficient use of available host plant resistances. Long-read sequencing technology allowed us to generate a new reference genome of G. pallida population D383 and, as compared to the current reference, the new genome assembly is 42 times less fragmented. For comparison of diversification patterns of six effector families between G. pallida and G. rostochiensis, an additional reference genome was generated for an outgroup, the beet cyst nematode Heterodera schachtii (IRS population). Large evolutionary contrasts in effector family topologies were observed. While VAPs diversified before the split between the three cyst nematode species, the families GLAND5 and GLAND13 only expanded in PCN after their separation from the genus Heterodera. Although DNA motifs in the promoter regions thought to be involved in the orchestration of effector expression ( DOG boxes) were present in all three cyst nematode species, their presence is not a necessity for dorsal gland-produced effectors. Notably, DOG box dosage was only loosely correlated with expression level of individual effector variants. Comparison of the G. pallida genome with those of two other cyst nematodes underlined the fundamental differences in evolutionary history between effector families. Re-sequencing of PCN populations with deviant virulence characteristics will allow for the linking of these characteristics with the composition of the effector repertoire as well as for the mapping of PCN diversification patterns resulting from extreme anthropogenic range expansion.

genomics↗

bioRxiv2021

Two evolutionary distinct effectors from a nematode and virus target RanGAP1 and 2 via the WPP domain to promote disease

The Gpa2 and Rx1 intracellular immune receptors are canonical CC-NB-LRR proteins belonging to the same R gene cluster in potato. Despite sharing high sequence homology, they have evolved to provide defence against unrelated pathogens. Gpa2 detects Gp-RBP-1 effectors secreted by the potato cyst nematode Globodera pallida whereas Rx1 recognizes the viral coat protein (CP) of Potato Virus X (PVX). How Gpa2 and Rx1 perceive their matching effectors remains unknown. Using a combination of in planta Co-Immunoprecipitation and cellular imaging, we show that both Gp-RBP-1 and PVX-CP physically interact with RanGAP2 and RanGAP1 in the cytoplasm of plant cells. Interestingly, this was also demonstrated for the eliciting variants of Gp-RBP-1 and PVX-CP indicating a role for RanGAP1 and RanGAP2 in pathogenicity independent from Gpa2 and Rx1 recognition. Indeed, knocking down both RanGAP homologs reduce cyst nematode and PVX infection. These findings show that RanGAP1/2 act as common host targets of evolutionary distinct effectors from two plant pathogens with different lifestyles. The involvement of RanGAP1/2 to pathogen virulence is a novel role not yet reported for these key host cell components and as such, their possible role in cyst nematode parasitism and viral pathogenicity are discussed. Moreover, from these findings a model emerges for their possible role as co-factor in pathogen recognition by the potato immune receptors Gpa2/Rx1.

plant biology↗

bioRxiv2021

Glycine-Rich RNA-Binding Protein 7 interacts with and potentiates effector-induced immunity by Gpa2 and Rx1 based on an intact RNA Recognition Motif

O_LIThe activity of intracellular plant Nucleotide-Binding Leucine-Rich Repeat (NB-LRR) immune receptors is fine-tuned by interactions between the receptors and their partners. Identifying NB-LRR interacting proteins is, therefore, crucial to advance our understanding of how these receptors function. C_LIO_LIA Co-Immunoprecipitation/Mass-Spectrometry screening was performed in Nicotiana benthamiana to identify host proteins associated with the Gpa2 CC-NB-LRR, which confers resistance against the potato cyst nematode Globodera pallida. A combination of biochemical, cellular, and functional assays was used to assess the role of a candidate interactor in defence. C_LIO_LIA N. benthamiana homolog of the Glycine-Rich RNA-Binding Protein 7 (NbGRP7) protein was prioritized as a novel Gpa2-interacting protein for further investigations. NbGRP7 also associates in planta with the homologous Rx1 receptor, which confers immunity to Potato Virus X. We show that NbGRP7 positively regulates extreme resistance by Rx1 and cell death by Gpa2. Mutating the NbGRP7 RNA recognition motif compromises its role in Rx1-mediated defence. Strikingly, ectopic NbGRP7 expression impacts the steady-state levels of Rx1, which relies on an intact RNA recognition motif. C_LIO_LICombined, our findings illustrate that NbGRP7 is a novel pro-immune component in effector-triggered immunity by regulating Gpa2/Rx1 functioning at a post-transcriptional level. C_LI

plant biology↗

bioRxiv2021

Comparative Genomics of two Inbred Lines of the Potato Cyst Nematode Globodera rostochiensis reveals disparate Effector Family-specific Diversification Patterns

BackgroundPotato cyst nematodes belong to the most harmful pathogens in potato, and durable management of these soil-borne parasites largely depends on host-plant resistances. These resistances are pathotype specific. The current Globodera rostochiensis pathotype scheme that defines five pathotypes (Ro1 - Ro5) is for fundamental and practical reasons barely useful. As a result, resistant potato varieties are worldwide used in a non-informed manner. ResultsWe generated two novel reference genomes of G. rostochiensis inbred lines derived from a Ro1 and a Ro5 population. These genome sequences comprise 173 and 189 scaffolds respectively, marking a {approx} 24-fold reduction in fragmentation as compared to the current reference genome. We provide copy number variations for 18 effector families. Four dorsal gland effector families were investigated in more detail. SPRYSECs, known to be implicated in immune suppression, constitute by far the most diversified family with 60 and 99 variants in Ro1 and Ro5 distributed over 18 and 26 scaffolds. In contrast, CLEs, effectors involved in feeding site induction, show strong physical clustering. The 10 and 16 variants cluster on respectively 2 and 1 scaffolds. Given that pathotypes are defined by their effectoromes, we pinpoint the disparate nature of the contributing effector families in terms of sequence diversification and loss and gain of variants. ConclusionTwo novel reference genomes allow for nearly complete inventories of effector diversification and physical organisation within and between pathotypes. Combined with insights we provide on effector family-specific diversification patterns, this constitutes a solid basis for an effectorome-based virulence scheme for this notorious pathogen.

genomics↗

bioRxiv2021

Plant pathogens convergently evolved to counteract redundant nodes of an NLR immune receptor network

In plants, NLR (nucleotide-binding domain and leucine-rich repeat-containing) proteins can form receptor networks to confer hypersensitive cell death and innate immunity. One class of NLRs, known as NRCs (NLR required for cell death), are central nodes in a complex network that protects against multiple pathogens and comprises up to half of the NLRome of solanaceous plants. Given the prevalence of this NLR network, we hypothesized that pathogens convergently evolved to secrete effectors that target NRC activities. To test this, we screened a library of 167 bacterial, oomycete, nematode and aphid effectors for their capacity to suppress the cell death response triggered by the NRC-dependent disease resistance proteins Prf and Rpi-blb2. Among five of the identified suppressors, one cyst nematode protein and one oomycete protein suppress the activity of autoimmune mutants of NRC2 and NRC3, but not NRC4, indicating that they specifically counteract a subset of NRC proteins independently of their sensor NLR partners. Whereas the cyst nematode effector SPRYSEC15 binds the nucleotide-binding domain of NRC2 and NRC3, the oomycete effector AVRcap1b suppresses the response of these NRCs via the membrane trafficking-associated protein NbTOL9a (Target of Myb 1-like protein 9a). We conclude that plant pathogens have evolved to counteract central nodes of the NRC immune receptor network through different mechanisms. Coevolution with pathogen effectors may have driven NRC diversification into functionally redundant nodes in a massively expanded NLR network.

plant biology↗

bioRxiv2019

SIZ1 is a nuclear host target of the nematode effector GpRbp1 from Globodera pallida that acts as a negative regulator of basal plant defense to cyst nematodes

Soil-borne cyst nematodes are obligatory sedentary parasites that cause severe losses to cultivation of major crops such as potato and soybean. Cyst nematodes establish specialised permanent feeding sites within the roots of their host by manipulating plant morphology and physiology through secreted effectors. Here we identified host targets of effector GpRbp-1 and studied their roles in plant-nematode interactions. GpRbp-1 was found to interact in yeast and in planta with the potato and Arabidopsis homologues of Siz/PIAS-type E3 SUMO ligase SIZ1. Our results show that a pathogen effector targets the master regulator SIZ1 in plant cells, which has not been demonstrated earlier to our knowledge. The interaction of GpRbp-1 and SIZ1 localizes to the plant nucleus, suggesting that the nuclear functions of SIZ1 as regulator of plant immunity and physiology may be modulated by GpRbp-1. Furthermore, nematode infection assays and transcriptomic profiling indicate that SIZ1 is required for susceptibility to cyst nematodes. So, these data indicate that E3 SUMO ligases may play an important role in plant-nematode interactions. Based on the prediction of SUMO acceptor and interaction sites in GpRbp-1, a model is proposed in which the effector may recruit SIZ1 to be SUMOylated for full functionality in host cells.\n\nSignificance statementHere we show that a pathogen effector can target SIZ1, a key protein involved in regulating several aspects of plant biology, most likely to manipulate the SUMOylation of host proteins for successful infection of plants.

plant biology↗