Biology subjects

Caravel, C.

Publications and source records attributed to Caravel, C..

5 recordsLinked to original sources

bioRxiv2026

The root knot nematode effector MiEFF186 interacts with a splicing factor to reshape plant transcriptome

The root-knot nematode Meloidogyne incognita secretes specific effectors to manipulate root cells and induce their redifferentiation into multinucleate feeding giant cells, which are essential for its development. A dedicated screen identified the M. incognita MiEFF186a effector as a regulator of alternative splicing, a crucial mechanism of transcriptional gene regulation whereby a single gene can produce multiple mature mRNA variants, in plants. EFF186 is expressed in the esophageal glands of nematode juveniles, and in planta, it localizes to the nucleus and accumulates in the nucleolus. A yeast two-hybrid approach identified the nucleolar G-patch protein GDP1/CIS2 as a MiEFF186a target in tomato and Arabidopsis. Transcriptomic analyses of Arabidopsis roots ectopically expressing MiEFF186a or impaired in GDP1/CIS2 function revealed changes in both gene expression and alternative splicing, with partially overlapping responses. Finally, alteration of GDP1/CIS2 expression by virus-induced gene silencing in Solanaceae or in Arabidopsis gdp1 mutants affects susceptibility to M. incognita. Together, these results identify GDP1/CIS2 as a host target of MiEFF186a and support a role for these proteins in the modulation of host RNA metabolism during nematode parasitism.

plant biology↗

bioRxiv2026

Diversity of egg parasitoids of stink bugs in France, with emphasis on Scelionidae parasitizing main Pentatomidae pests.

Stink bugs (Hemiptera Pentatomidae) are major agricultural pests worldwide, including both native and invasive species. In France, for instance, Halyomorpha halys has rapidly expanded its range, affecting key crops such as hazelnuts, apples, and vegetables. Meanwhile, several native, polyphagous species - Nezara viridula, Palomena prasina and, to a lesser extent, Graphosoma italicum - are re-emerging and impacting diverse crops because of changes in agricultural practices and climatic conditions. Egg parasitoids represent promising biological control agents for these pests, be it through conservation, augmentation or introduction biological control. However, their actual potential is not precisely documented due to a lack of ambitious surveys and possible taxonomic issues. This study aims to address this gap by compiling results obtained from various of egg parasitism surveys of Pentatomidae in France and implementing a large-scale DNA Barcoding approach (2000 individuals) for the emerged parasitoids. Our results indicate a high diversity of egg parasitoids, and detected some taxonomic issues and molecular inconsistencies that warrant further study. Among the three families of egg parasitoids recovered (Encyrtidae, Eupelmide, and Scelionidae), Scelionidae was the most abundant and diverse with nine species of Trissolcus (including the two adventive species, Tr. japonicus and Tr. mitsukurii) and four Telenomus species (including two unidentified to species). Scelionidae dominated the parasitoid assemblages associated with most of the Pentatomidae host species, except for H. halys for which the eupelmid Anastatus bifasciatus was the most common species.

ecology↗

bioRxiv2026

A conserved root-knot nematode effector targets plant kinesin light chain related proteins to promote parasitism

Root-knot nematodes (RKNs) are obligate plant parasites that establish biotrophic interactions with a wide range of host plants, causing major crop losses worldwide. During infection, RKNs secrete effector proteins from their esophageal glands into root tissues via a stylet. These effectors target specific subcellular compartments and manipulate host cell functions to induce the formation of hypertrophied and multinucleated giant cells, which serve as feeding sites essential for nematode development. Here we describe a new RKN-specific effector, EFFECTOR17 (EFF17), conserved in the five most damaging RKN species: Meloidogyne incognita, M. enterolobii, M. arenaria, M. javanica, and M. hapla. In situ hybridization showed that EFF17 genes are specifically expressed in the esophageal glands of various RKN species. Silencing EFF17 in M. incognita reduced its reproduction on Nicotiana benthamiana, demonstrating a key role in parasitism. Yeast two-hybrid and split luciferase assays revealed that tomato and Arabidopsis KINESIN LIGHT CHAIN RELATED (KLCR)/CELLULOSE-MICROUBULE UNCOUPLING (CMU) proteins are host targets of MiEFF17. Arabidopsis klcr mutants developed significantly fewer galls and egg masses. Our findings propose that EFF17 manipulates KLCR function to promote parasitism.

plant biology↗

bioRxiv2024

Identification and Expression of the peach TNL RMia genes for the Resistance to the Root-knot Nematode Meloidogyne incognita

Root-Knot Nematodes (RKN) are major pests for world agriculture. As RKN are polyphagous endoparasites, present in various climates and able to multiply rapidly, the quest to discover new natural resistances in plants is essential. In Prunus species, several major resistance genes to RKN that belong to the NLR family, have been detected in recent years. In Peach, the RMia gene, which confers resistance to the RKN Meloidogyne incognita, M. arenaria, and M. ethiopica, was localized on the chromosome 2. In this study, we used short-and long-read sequencing technologies to identify the RMia gene in two independent RKN-resistant peach varieties. We characterized three candidate genes and studied their expression profile upon RKN infection. Our study identified and characterized these candidates that are most likely involved in the RKN resistance. Ultimately, we developed new molecular markers associated to this resistance that can be used in breeding programs.

plant biology↗

bioRxiv2020

Consistent variations in personality traits and their potential for genetic improvement in the biocontrol agent Trichogramma evanescens

Improvements in the biological control of agricultural pests require improvements in the phenotyping methods used by practitioners to select efficient biological control agent (BCA) populations in industrial rearing or field conditions. Consistent inter-individual variations in behaviour (i.e. animal personality) probably affect BCA efficiency, but have never been taken into account in the development of phenotyping methods, despite having characteristics useful for phenotyping: repeatable (by definition), often heritable, etc. We developed a video-tracking method targeting animal personality traits and evaluated the feasibility of its use for genetic improvement in the BCA Trichogramma evanescens, by phenotyping 1,049 individuals from 24 isogenic lines. We found consistent individual variations in boldness, activity and exploration. Personality differences between the 24 isogenic lines suggested a genetic origin of the variations in activity and exploration (broad-sense heritability estimates of 0.06 to 0.11) and revealed a trade-off between exploration and fecundity.

ecology↗