Biology subjects

Gheysen, G.

Publications and source records attributed to Gheysen, G..

4 recordsLinked to original sources

bioRxiv2025

THE ROOT-KNOT NEMATODE EFFECTOR MJ-MSP18: A SWISS ARMY KNIFE FOR REPROGRAMMING PLANT IMMUNITY

Root-knot nematodes (Meloidogyne spp.) are obligatory plant root parasites whose effector proteins play a critical role in suppressing plant immunity. However, the effectors direct host targets and underlying molecular mechanisms remain poorly understood. Using TurboID-mediated proximity labeling in tomato (Solanum lycopersicum) hairy roots, we identified an interaction between the nematode effector Mj-MSP18 and the tomato BRASSINOSTEROID-SIGNALING KINASE 7 (Sl-BSK7). Yeast two-hybrid (Y2H) assays confirmed that this interaction is conserved in Arabidopsis thaliana and Nicotiana benthamiana. Additionally, yeast three-hybrid and luciferase complementation assays demonstrated that Mj-MSP18 disrupts the interaction between BSK7/8 and FLS2 in both yeast and in planta. Given that the BSK7/8-FLS2 interaction is essential for flg22-induced pattern-triggered immunity (PTI), this disruption likely accounts for the suppression of reactive oxygen species (ROS) production and callose deposition observed upon transient expression of Mj-MSP18 in flg22-treated N. benthamiana leaves. Correspondingly, Arabidopsis and tomato bsk7 mutants exhibited increased susceptibility to root-knot nematode infection. Furthermore, RNA-seq analysis of tomato hairy roots expressing Mj-MSP18 revealed extensive transcriptional reprogramming, including the downregulation of defence-related genes and hydrogen peroxide response pathways. In addition, Y2H screening identified Sl-MYB and Sl-MYC2 as additional interactors, linking Mj-MSP18 to phytohormone biosynthesis, particularly the brassinosteroid (BR) and salicylic acid (SA) pathways, as validated by targeted metabolite analysis. The conservation of Mj-MSP18 across Meloidogyne species suggests a broadly conserved mechanism for host immune suppression and phytohormone modulation.

plant biology↗

bioRxiv2022

The nematode effector Mj-NEROSs interacts with ISP influencing plastid ROS production to suppress plant immunity

Root-knot nematodes are an important group of plant pathogens that mainly infect plant roots. They establish a feeding site in the host upon infection while secreting hundreds of effectors. These effector proteins are crucial for successful pathogen propagation. Although many effectors have been described, their targets and molecular mode of action are still unknown. Here we report the analysis of the RKN effector, Mj-NEROSs (Meloidogyne javanica nematode effector ROS suppressor), which emerges to have an essential role in suppressing host immunity by inhibiting INF1-induced cell death and reducing callose deposition. Secreted from the subventral esophageal glands to giant cells, Mj-NEROSs localizes in plastids where it interacts with ISP, interfering with the electron transport rate and ROS production. Moreover, our transcriptome analysis shows the downregulation of ROS-related genes upon Mj-NEROSs expression. We propose that Mj-NEROSs manipulates root plastids leading to transcriptional changes, lowering ROS production, and suppressing host immunity.

plant biology↗

bioRxiv2022

Horizontal transferred T-DNA and haplotype-based phylogenetic analysis uncovers the origin of sweetpotato

The hexaploid sweetpotato is one of the most important root crops worldwide. However, its genetic origins are controversial. In this study, we identified two progenitors of sweetpotato by horizontal gene transferred IbT-DNA and haplotype-based phylogenetic analysis. The diploid progenitor is the diploid form of I. aequatoriensis, contributed the B1 subgenome, IbT-DNA2 and lineage 2 type of chloroplast genome to sweetpotato. The tetraploid progenitor of sweetpotato is I. batatas 4x, donating the B2 subgenome, IbT-DNA1 and lineage 1 type of chloroplast genome. Sweetpotato derived from the reciprocal cross between the diploid and tetraploid progenitors and a subsequent whole genome duplication. We also detected biased gene exchanges between subgenomes. The B1 to B2 subgenome conversions were almost 3-fold higher than the B2 to B1 subgenome conversions. This study sheds lights on the evolution of sweetpotato and paves a way for the improvement of sweetpotato.

evolutionary biology↗

bioRxiv2020

Towards genetic modification of plant-parasitic nematodes: delivery of macromolecules to adults and expression of exogenous mRNA in second stage juveniles.

Plant-parasitic nematodes are a continuing threat to food security, causing an estimated 100 billion USD in crop losses each year. The most problematic are the obligate sedentary endoparasites (primarily root knot nematodes and cyst nematodes). Progress in understanding their biology is held back by a lack of tools for functional genetics: forward genetics is largely restricted to studies of natural variation in populations, and reverse genetics is entirely reliant on RNA interference. There is an expectation that the development of functional genetic tools would accelerate the progress of research on plant-parasitic nematodes, and hence the development of novel control solutions. Here, we develop some of the foundational biology required to deliver a functional genetic tool kit in plant-parasitic nematodes. We characterise the gonads of male Heterodera schachtii and Meloidogyne hapla in the context of spermatogenesis. We test and optimise various methods for the delivery, expression, and/or detection of exogenous nucleic acids in plant-parasitic nematodes. We demonstrate that delivery of macromolecules to cyst and root knot nematode male germlines is difficult, but possible. Similarly, we demonstrate the delivery of oligonucleotides to root knot nematode gametes. Finally, we develop a transient expression system in plant-parasitic nematodes by demonstrating the delivery and expression of exogenous mRNA encoding various reporter genes throughout the body of H. schachtii juveniles using lipofectamine-based transfection. We anticipate these developments to be independently useful, will expedite the development of genetic modification tools for plant-parasitic nematodes, and ultimately catalyze research on a group of nematodes that threaten global food security.

genetics↗