Biology subjects

Sauvion, N.

Publications and source records attributed to Sauvion, N..

7 recordsLinked to original sources

bioRxiv2026

Aphid stylin cuticular proteins contribute to turnip mosaic virus (Potyvirus) transmission

Hundreds of plant viruses are transmitted by aphid vectors, among which non-circulative ones are acquired and inoculated from one host to another within seconds. These viruses are retained on receptors located at the surface of the cuticle of aphid mouthparts. Members of the Potyviridae family are the most abundant RNA viruses infecting plants, and they cause significant economic losses. Among them, viruses of the Potyvirus genus are transmitted by aphids in a stylet-borne manner. Their receptors in aphid stylets remain poorly characterized. Using turnip mosaic virus (TuMV, Potyvirus rapae) as a model, we developed complementary approaches to investigate potyvirus-aphid interactions in three vector species. Immunofluorescence detection and transmission electron microscopy revealed the presence of TuMV in the distal part of aphid maxillary stylets, both in the food canal and on the acrostyle. This cuticular organ houses Stylin proteins, including Stylin-01, the receptor for the cauliflower mosaic virus (Caulimovirus tesselobrassicae). Using CRISPR-Cas9-edited Stylin-01 mutant lines in the pea aphid, we demonstrated that this protein plays an important role in TuMV transmission. Complementary RNA interference silencing experiments revealed that Stylin-04/04bis also mediate TuMV transmission. Furthermore, our findings reveal that targeting simultaneously Stylin-01 and Stylin-04/04bis more strongly impaired the aphids ability to transmit TuMV, suggesting that virus transmission relies on a multi-component stylin interface rather than a single receptor. In conclusion, these results highlight that in complex interactions between potyviruses and their aphid vectors, Stylin proteins are key actors, underscoring their importance in the transmission of stylet-borne viruses. Author summaryPotyviruses are the largest group of plant-infecting RNA viruses and major threats to crops worldwide. Aphids can transmit them within seconds retaining virus particles on their needle-like mouthparts through specific interactions at the stylet surface. However, the identity of the aphid proteins involved in this process has remained unknown. Using turnip mosaic virus (TuMV), a potyvirus with an exceptionnally broad host ranges, we provide evidence of virus retention at the acrostyle, a specialized cuticular microstructure at the tip of aphid stylets. CRISPR-Cas9 stable aphid mutant lines and RNAi-mediated gene silencing revealed that the acrostyle cuticular proteins Stylin-01 and Stylin04/04bis promote TuMV transmission. These findings uncover previously unknown molecular components of the aphid-potyvirus interface and identify potential targets to disrupt virus-vector interaction and virus transmission.

microbiology↗

bioRxiv2026

AnthropInsect: a global database of insect traits and anthropogenic associations.

Insect research remains hindered by limited data availability and fragmented knowledge compared to other, better-documented taxonomic groups. Yet, both the macroecological and the insect research communities highlight the need to integrate large-scale ecological trait datasets for insects. Insects and humans are interconnected through diverse relationships, ranging from beneficial interactions, such as the use of insects as nutritional resources, to adverse impacts, including their role in to the emergence and spread of biological invasions. Understanding the traits of insects associated with human use, movement and impact is therefore important for linking insects to ecosystem function and global change. We present AnthropInsect, one of the largest database on insect traits to date, which uniquely includes variables describing human-insect associations. AnthropInsect describes species through 35 variables grouped into five categories: (i) taxonomic descriptors; (ii) ecological descriptors (native bioregions and habitat); (iii) human-insect associations (edibility and invasive status); (iv) functional traits (behavior, morphology, life history and feeding); (v) and macroecological descriptors of native-range geography and climate. AnthropInsect currently includes 5867 species across six major orders: Coleoptera, Lepidoptera, Hemiptera, Hymenoptera, Orthoptera and Blattodea. Data extracted from peer-reviewed, grey literature and from existing databases were standardized and validated with expert knowledge to ensure accuracy. By providing traits data with information on insect-human interactions, this rigorously curated resource supports global research in entomology, ecology, conservation, and global change.

ecology↗

bioRxiv2024

Origin, divergence and migration routes of psyllids of the Cacopsylla pruni complex (Hemiptera: Psylloidea) inferred by Approximate Bayesian Computation methods

Population genetics is essential to decipher the evolutionary history of pests and insect vectors from both a theoretical point of view and to predict and mitigate the future of epidemics. We attempt to shed light on the evolutionary history and phylogeography of two cryptic psyllid species (namely A and B) of the Cacopsylla pruni complex, vectors of Candidatus phytoplasma prunorum. It is known to cause the European stone fruit yellows (ESFY), a disease affecting Prunus trees and causing significant crop losses each year. Analyses were conducted to decipher the origin, order and time of divergence, as well as the migration routes of the species complex in the Western Palearctic. We used mitochondrial and nuclear gene data to infer the population genetic diversity and structure of the complex, and to reconstruct a dated phylogenetic tree of the Psyllinae family in order to subsequently perform Approximate Bayesian Computation analyses. Both species have diverged in what is now France from a common ancestor, around 20.19 Mya, before expanding into Spain around 6.61 Mya for species A and Eastern Europe around 6.36 Mya for species B. Then species B seem to have passed into Corsica during the Messinian salinity crisis (5.96-5.33 Mya) from French or Italian B populations. No apparent admixture was found between both species after their divergence, which would indicate an absence of gene flow between them at the point when they recolonised common ecological niches. This strong genetic differentiation confirms previous work on reproductive barriers between the two species.

molecular biology↗

bioRxiv2020

Alfalfa leaf curl virus is efficiently acquired by its aphid vector Aphis craccivora but inefficiently transmitted

Alfalfa leaf curl virus (ALCV) is the first geminivirus for which an aphid transmission was reported. Transmission by Aphis craccivora was determined previously to be highly specific and circulative. Using various complementary techniques, the transmission journey of ALCV was monitored from its uptake in an infected plant tissue up to the head of its vector. ALCV was shown to be restricted in the phloem using fluorescent in situ hybridization (FISH) and electropenetrography (EPG) monitoring of virus acquisition. Furthermore, the virus is heterogeneously distributed in the phloem as revealed by FISH and qPCR quantification of the viral DNA acquired by aphids monitored by EPG. In spite of the efficient ingestion of viral DNA, about 106 in a 15-hour feeding on ALCV infected plants, the individual transmission rate was at a maximum of 12%. Transmission success was related to a critical viral accumulation, around 1.6x107 viral DNA copies per insect, a threshold that needs generally more than 48 hours to be reached. Moreover, whereas the amount of acquired virus does not decrease over time in the whole aphid body, it decreased in hemolymph and heads. ALCV was not detected in progenies of viruliferous aphids and had no effect on aphid fitness. Compared to geminiviruses transmitted by whiteflies or leafhoppers or to luteovirus transmitted by aphids, the transmission efficiency of ALCV by A. craccivora is low. This result is discussed in relation to the aphid vector of this geminivirus and the agroecological features of alfalfa, a hardy perennial host plant.

ecology↗

bioRxiv2019

Alfalfa leaf curl virus is transmitted by Aphis craccivorain a highly specific circulative manner

Two members of the genus Capulavirus (Geminiviridae) are transmitted by aphids including Alfalfa leaf curl virus (ALCV) transmitted by Aphis craccivora. The capulavirus Euphorbia caput-medusae latent virus was shown here to be transmitted also by A. craccivora, using the population EuphorbiaSA. ALCV was transmissible by several A. craccivora populations including Robinia, but not EuphorbiaSA, reflecting a high transmission specificity. ALCV accumulation and localization were analyzed in whole insects, midguts, hemolymphs, and heads of aphids from both populations and from the non-vector species Acyrthosiphon pisum. A 6-day persistence was observed in A. craccivora populations but not in A. pisum. Vector and non-vector A. craccivora populations could be distinguished by contrasted virus accumulations and midgut intracellular localization. Results confirm that ALCV is transmitted according to a circulative-persistent mode, and are consistent with a gut barrier to the transmission of ALCV in A. pisum and a primary salivary gland barrier in A. craccivora.

ecology↗

bioRxiv2019

Multi-scale spatial genetic structure of a vector-borne plant pathogen in orchards and wild habitat

Inferring the dispersal processes of vector-borne plant pathogens is a great challenge because the plausible epidemiological scenarios often involve complex spread patterns at multiple scales. European stone fruit yellows (ESFY), a disease caused by Candidatus Phytoplasma prunorum and disseminated via planting material and vectors belonging to the species Cacopsylla pruni, is a major threat for stone fruit production throughout Europe. The spatial genetic structure of the pathogen was investigated at multiple scales by the application of a combination of statistical approaches to a large dataset obtained through the intensive sampling of the three ecological compartments hosting the pathogen (psyllids, wild and cultivated Prunus) in three Prunus-growing regions in France. This work revealed new haplotypes of Ca. P. prunorum, and showed that the prevalence of the different haplotypes of this pathogen is highly uneven between all regions, and within two of them. In addition, we identified a significant clustering of similar haplotypes within a radius of at most 50 km, but not between nearby wild and cultivated Prunus. We also provide evidence that the two species of the C. pruni complex are unevenly distributed but can spread the pathogen, and that infected plants are transferred between production areas. Altogether, this work supports a main epidemiological scenario where Ca. P. prunorum is endemic in, and mostly acquired from, wild Prunus by immature C. pruni (of both species) who then migrate to \"shelter plants\" that epidemiologically connect sites less than 50 km apart by later providing infectious mature C. pruni to their \"migration basins\", which differ in their haplotypic composition. We argue that such multiscale studies would be very useful for other pathosystems.

ecology↗

bioRxiv2018

A framework for estimating the effects of sequential reproductive barriers: implementation using Bayesian models with field data from cryptic species

Determining how reproductive barriers modulate gene flow between populations represents a major step towards understanding the factors shaping the course of speciation. Although many indices quantifying reproductive isolation (RI) have been proposed, they do not permit the quantification of cross direction-specific RI under varying species frequencies and over arbitrary sequences of barriers. Furthermore, techniques quantifying associated uncertainties are lacking, and statistical methods unrelated to biological process are still preferred for obtaining confidence intervals and p-values. To address these shortcomings, we provide new RI indices that model changes in gene flow for both directions of hybridization, and we implement them in a Bayesian model. We use this model to quantify RI between two species of the psyllid Cacopsylla pruni based on field genotypic data for mating individuals, inseminated spermatophores and progeny. The results showed that pre-insemination isolation was strong, mildly asymmetric and undistinguishably different between study sites despite large differences in species frequencies; that post-insemination isolation strongly affected the more common hybrid type; and that cumulative isolation was close to complete. In the light of these results, we discuss how these developments can strengthen comparative RI studies.\n\nAuthor contributionsJP and NS initiated the study and obtained biological data. JP and DRJP developed the porosity-based approach. DRJP conceived the Bayesian implementation and code. JP, DRJP and NS wrote the manuscript.\n\nData availabilityMitochondrial sequence data will be available at Genbank, source code is available at xxx.

evolutionary biology↗