Biology subjects

Herrero, S.

Publications and source records attributed to Herrero, S..

13 recordsLinked to original sources

bioRxiv2026

Insect REPAT proteins mediate cross-kingdom communication in microbe-insect-plant interactions

Plant-herbivore interactions are embedded within complex ecological networks in which microorganisms associated with either partner can reshape interactions across trophic levels. Yet how microbial infections of herbivorous insects alter the molecular signals they deliver to plants remains largely unexplored. Here, we identify REPAT proteins as key molecular mediators linking microbial infection in caterpillars to plant defense responses. Comparative genomic analyses revealed that REPATs comprise an insect protein family that has expanded in Lepidoptera, with a conserved {beta}-REPAT lineage and rapidly diversifying - and {gamma}-REPAT lineages, the latter encompassing most REPATs previously implicated in plant interactions. Proteomic analyses of caterpillar oral secretions revealed that viruses with contrasting infection strategies exerted opposite effects on REPAT abundance. Infection with the lethal baculovirus Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV) increased the abundance of multiple REPAT proteins, whereas infection with the persistent, covert iflavirus Spodoptera exigua iflavirus 1 (SeIV1) consistently reduced REPAT abundance across dietary conditions. These changes were associated with reciprocal effects on plant defense: herbivory by SeMNPV-infected larvae attenuated jasmonate-associated responses in tomato, whereas SeIV1-infected larvae enhanced defense activation in pepper. Together, our findings reveal that viral infection of the herbivore can propagate across trophic levels and reshape plant responses to herbivory by altering the repertoire of effectors delivered during feeding, uncovering a mechanism through which insect-microbe interactions can influence plant defense.

ecology↗

bioRxiv2026

Charge-Driven Fibril Recognition and Covalent Disruption of Aβ42 byPaddlewheel Diruthenium Complexes

The inhibition of A{beta}42 ({beta}-amyloid) fibril formation is a key therapeutic strategy in Alzheimers disease research. Paddlewheel diruthenium complexes have shown promising activity against A{beta}42 aggregation and preformed fibril disaggregation, yet their molecular mode of action remains poorly understood. In this work, we perform atomistic simulations to explore how charge modulation influences the interactions of three analogous paddlewheel diruthenium complexes, the parent neutral complex [Ru2Cl(D-p-FPhF)(O2CCH3)3], and its anionic [Ru2Cl2(D-p-FPhF)(O2CCH3)3]- and cationic [Ru2(D-p-FPhF)(O2CCH3)3]+ counterparts (D-p-FPhF- is the N,N -bis(4-fluorophenyl)formamidinato ligand) with A{beta}42. Our results indicate that electrostatic tuning governs binding affinity and the extent of interaction across the A{beta}42 fibril surface. As the complexes charge changes from -1 to +1, the interaction pattern shifts from localized contacts to widespread, multi-site engagement encompassing key charged, aromatic, and hydrophobic regions of A{beta}42. This enhanced binding correlates with longer-lived, thermodynamically stable interactions at the fibril interface, which effectively lower the free energy penalty for fibril disassembly. Overall, our findings propose a mechanism in which charge-dependent activation through ligand exchange enhances fibril recognition and promotes disruptive binding modes, demonstrating the potential of charge-tunable diruthenium complexes as therapeutic modulators of A{beta}42 fibril stability.

biophysics↗

bioRxiv2025

A solinvivirus induces cellular antiviral response and reduces the lifespan of adult Hermetia illucens (black soldier flies)

Viral pathogens pose an emerging threat to the sustainability of insect mass-rearing systems, yet remain understudied in key species like the black soldier fly (BSF, Hermetia illucens). Although multiple viral sequences have been reported in BSF, their role in disease has not been established until now. Here, we provide the first in vivo characterisation of Hermetia illucens solinvivirus (HiSvV), confirming its role as a viral entomopathogen of BSF. Metatranscriptomic analysis of a diseased colony revealed a high viral load attributable to HiSvV. We successfully isolated the virus and developed injection- and oral-based infection assays to investigate replication, tissue tropism, transmission and risk of mortality. HiSvV replicated in inoculated adults, induced premature mortality in flies, and was transmitted both horizontally and vertically. Infected flies also mounted a broad antiviral response, supporting active pathogenesis. These findings establish HiSvV as the first confirmed viral pathogen of BSF and underscore the urgent need for viral surveillance and experimental tools to safeguard industrial insect rearing.

microbiology↗

bioRxiv2024

Characterization of the Tuta absoluta virome reveals higher viral diversity in field populations

A significant number of insect-specific viruses (ISVs) have been discovered in agriculturally important insect pests, facilitated by high-throughput sequencing (HTS). Despite its global impact on tomato crops, the RNA virome of the South American tomato pinworm, Tuta absoluta, remains uncharacterized. In this study, we utilized meta-transcriptomics and bioinformatic approaches to discover the RNA virome of T. absoluta across worldwide populations. We identified ten novel ISVs, classified into six groups: Nidovirales, Bunyavirales, Mononegavirales, Virgaviridae, Iflaviridae, Nodaviridae, Solemoviridae, and Phasmaviridae. Notably, no core virus was consistently present across the studied populations, and field-collected samples revealed a greater diversity of ISVs compared to those from laboratory samples. In addition, we detected plant-infecting viruses and mycoviruses associated with the pest. This study represents the first description of the RNA virome associated with T. absoluta, providing valuable insights into its biological and ecological interactions. It also lay the foundation for future studies aimed to clarify the biological roles of ISVs.

microbiology↗

bioRxiv2024

Optimization of screening methods leads to the discovery of new viruses in black soldier flies (Hermetia illucens)

Virus discovery in mass-reared insects is a growing topic of interest due to outbreak risks and for insect welfare concerns. In the case of black soldier flies (BSF), pioneering bioinformatic studies have uncovered exogenous viruses from the orders Ghabrivirales and Bunyavirales, as well as endogenous viral elements from five virus families. This prompted further virome investigation of BSF metagenomes and metatranscriptomes, including from BSF individuals displaying signs and symptoms of disease. In this study, we describe five newly discovered viruses from the families Dicistroviridae, Iflaviridae, Rhabdoviridae, Solinviviridae, and Inseviridae. These viruses were detected in BSF from multiple origins, outlining a diversity of naturally occurring viruses associated with BSF. This viral community may also include BSF pathogens. The growing list of viruses found in BSF allowed the development of molecular detection tools which could be used for viral surveillance, both in mass-reared and wild populations of BSF.

microbiology↗

bioRxiv2023

Covert RNA viruses in medflies differ in their mode of transmission and tissue tropism

Numerous studies have demonstrated the presence of covert viral infections in insects. These infections can be transmitted in insect populations via two main routes: vertical from parents to offspring, or horizontal between nonrelated individuals. Thirteen covert RNA viruses have been described in the Mediterranean fruit fly (medfly). Some of these viruses are established in different laboratory-reared and wild medfly populations, although variations in the viral repertoire and viral levels have been observed at different time points. To better understand these viral dynamics, we characterized the prevalence and levels of covert RNA viruses in two medfly strains, assessed the route of transmission of these viruses, and explored their distribution in medfly adult tissues. Altogether, our results indicated that the different RNA viruses found in medflies vary in their preferred route of transmission. Two iflaviruses and a narnavirus are predominantly transmitted through vertical transmission via the female, while a nodavirus and a nora virus exhibited a preference for horizontal transmission. Overall, our results give valuable insights into the viral tropism and transmission of RNA viruses in the medfly, contributing to the understanding of viral dynamics in insect populations.

ecology↗

bioRxiv2022

Beyond viral detection: multitrophic effects of covert infection with an RNA virus in medfly.

Summary/abstractO_ST_ABSBackgroundC_ST_ABSWith the advent of high-throughput sequencing, large sets of insect-infecting RNA viruses producing apparent asymptomatic infections are being discovered. In the Mediterranean fruit fly (medfly) Ceratitis capitata, an agricultural key pest of a wide range of fruits, up to 13 different RNA viruses have been described. Recent analysis demonstrated a wide distribution of these viruses in different medfly strains collected worldwide, but little is known about the interactions between those viruses and the medfly host. Previous studies suggested that a higher abundance of Ceratitis capitata nora virus (CcaNV) decreased medfly developmental time. Here, we investigated the effect of CcaNV on a broad range of parameters related to host fitness and its interaction with other trophic levels. ResultsCcaNV purified from a naturally infected medfly strain was used to infect CcaNV-free flies orally and subsequently monitor pupal weight, adult emergence, flying ability and longevity. Our results revealed detrimental effects associated with a CcaNV infection in the medfly, in terms of reduced pupal weight and reduced adult longevity. Moreover, we tested the influence of a CcaNV infection in medflies on the parasitism performance of Aganaspis daci, a medfly endoparasitoid used in biological control programs against medflies. Our results showed that A. daci progeny increased when parasitizing on CcaNV-infected larvae. ConclusionsOur results proved that covert RNA viruses can impact on the insect ecology, directly affecting its insect host biology and indirectly influencing multitrophic interactions.

microbiology↗

bioRxiv2020

Neuropeptidome regulation after baculovirus infection. A focus on proctolin and its relevance in locomotion and digestion

Baculoviruses constitute a large group of invertebrate DNA viruses, predominantly infecting larvae of the insect order Lepidoptera. During a baculovirus infection, the virus spreads throughout the insect body producing a systemic infection in multiple larval tissues. Some behavioral and physiological changes in lepidopteran larvae have been described following a baculovirus infection and those changes could be connected with alterations in the hosts central nervous system (CNS). As a main component of the CNS, neuropeptides are small protein-like molecules functioning as neurohormones, neurotransmitters or neuromodulators. These peptides are involved in regulating animal physiology and behaviour and could also be targeted by baculoviruses in order to achieve host behavioural manipulations leading to increased viral fitness. In this study, we have investigated the effect of a Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV) infection on the neuropeptidome gene expression of Spodoptera exigua larval heads and brains. Expression of the gene encoding the neuropeptide proctolin was severely downregulated following infection and was chosen for further analysis. A recombinant Autographa californica multiple nucleopolyhedrovirus (AcMNPV) overexpressing the S. exigua proctolin gene was generated and used in bioassays using S. exigua larvae to study its influence on the viral infection. AcMNPV-proctolin infected larvae showed less locomotion activity and suffered a loss of weight compared to larvae infected with wild type AcMNPV or mock-infected larvae. These results provide additional information on the role of proctolin during a baculovirus infection, and offers a novel hypothesis for the molecular bases for the behavioral changes associated with a baculovirus infection.

genetics↗

bioRxiv2020

Coupling transcriptomics and behaviour to unveil the olfactory system of Spodoptera exigua larvae

Chemoreception in insects is crucial for many aspects related to food seeking, enemy avoidance, and reproduction. Different families of receptors and binding proteins interact with chemical stimuli, including odorant receptors (ORs), ionotropic receptors (IRs), gustatory receptors (GRs), odorant binding proteins (OBPs) and chemosensory proteins (CSPs). In this work, we describe the chemosensory-related gene repertoire of the worldwide spread pest Spodoptera exigua (Lepidoptera: Noctuide) focusing on the transcripts expressed in larvae, which feed on many horticultural crops producing yield losses. A comprehensive de novo assembly that includes reads from chemosensory organs of larvae and adults, and other larval tissues, enabled us to annotate 200 candidate chemosensory-related genes encoding 63 ORs, 28 IRs, 38 GRs, 48 OBPs and 23 CSPs. Of them, 51 transcripts are new annotations. RNA-seq and reverse transcription PCR analyses show that 50 ORs are expressed in larval heads, and 15 OBPs are larva-specific. To identify candidate ecologically-relevant odours for S. exigua larvae, we set up behavioural experiments with different volatile organic compounds (VOCs). 1-hexanol triggers attraction at the three timepoints tested and linalool repels larvae at any timepoints. Other five VOCs elicit behavioural response at single timepoint. Lastly, we tested if pre-exposure to single VOCs influence the expression patterns of selected ORs and pheromone binding proteins (PBPs), showing a massive and general up-regulation of some ORs after 24h exposure. This work sets the basis for the study of chemosensation in S. exigua larvae, boosting further studies aimed to characterize chemosensory-related genes that underlie ecologically-relevant behaviours of larval stage.

ecology↗

bioRxiv2019

The Toxin Cercosporin is a Virulence Factor for Infection of Coffee by Cercospora coffeicola

Brown eye spot, caused by Cercospora coffeicola, causes significant losses in both quality and quantity of coffee production. As many Cercospora spp. produce the photoactivated toxin cercosporin, this study aimed to determine the role of cercosporin in C. coffeicola pathogenesis by creating disruption mutants unable to produce the toxin. Six C. coffeicola isolates from Brazilian fields, representing organic and conventional production systems in the Minas Gerais state, were evaluated for their ability to produce cercosporin in vitro. Toxin production varied among isolates, ranging from 3.5 - 25.3 {micro}M/ 5 mm mycelial plug; production was undetectable in one isolate. The C. coffeicola homolog of the polyketide synthase gene (CTB1) involved in cercosporin production was amplified using a degenerate primer strategy. The 7044 nt ccCTB1 gene sequence was 90.3% identical to the cnCTB1 gene in Cercospora nicotianae and encoded a putative protein of 2196 amino acids with 98.2% similarity and 97.5% identity to its counterpart in C. nicotianae. Transformation of two isolates of C. coffeicola with a CTB1 disruption construct resulted in the recovery of six ctb1 disruption mutants. All of the ctb1 disruptants were deficient in cercosporin production. Disruption mutants did not differ significantly from the wild type for either growth or sporulation, but were significantly altered in virulence on coffee. As compared to wild type, time to lesion development was significantly increased and numbers of lesions were significantly decreased in coffee plants inoculated with ctb1 disruption mutants. These results show that cercosporin toxin is a virulence factor for C. coffeicola infection of coffee.

plant biology↗

bioRxiv2019

Improvement of baculovirus as protein expression vector and as biopesticide by CRISPR/Cas9 editing

The CRISPR (Clustered Regularly Interspaced Short Palindromic repeats) system associated Cas9 endonuclease is a molecular tool that enables specific sequence edition with high efficiency. The edition using CRISPR/Cas9 system has been successfully reported in small and large viral genomes. In this study, we have explored the use of CRISPR/Cas9 system for the edition of the baculovirus genome. We have shown that the delivering of Cas9-sgRNA ribonucleoprotein (RNP) complex with or without DNA repair template into Sf21 insect cells through lipofection might be efficient to produce knocks-out as well as knocks-in into the baculovirus. To evaluate potential application of our CRISPR/Cas9 method to improve baculovirus as protein expression vector and as biopesticide, we attempted to knock-out several genes from a recombinant AcMNPV form used in the baculovirus expression system as well as in a natural occurring viral isolate from the same virus. We have additionally confirmed the adaptation of this methodology for the generation of viral knocks-in specific regions of the viral genome. Analysis of the generated mutants revealed that the edition efficiency and the type of changes was variable but relatively high. Depending on the targeted gene, the rate of edition ranged from 10% to 40%. This study established the first report revealing the potential of CRISPR/Cas9 for the edition of baculovirus contributing to the engineering of baculovirus as protein expression vector as well as a biological control agent.

microbiology↗

bioRxiv2019

Identification of new viruses specific to the honey bee mite Varroa destructor

Large-scale colony losses among managed Western honey bees have become a serious threat to the beekeeping industry in the last decade. There are multiple factors contributing to these losses but the impact of Varroa destructor parasitism is by far the most important, along with the contribution of some pathogenic viruses vectored by the mite. So far, more than 20 viruses have been identified infecting the honey bee, most of them RNA viruses. They may be maintained either as covert infections or causing severe symptomatic infections, compromising the viability of the colony. In silico analysis of available transcriptomic data obtained from mites collected in the USA and Europe as well as additional investigation with new samples collected locally allowed the description of three novel RNA viruses. Our results showed that these viruses were widespread among samples and that they were present in the mites and in the bees but with differences in the relative abundance and prevalence. However, we have obtained strong evidence showing that these three viruses were able to replicate in the mite, but not in the bee, suggesting that they are selectively infecting the mite. To our knowledge, this is the first demonstration of Varroa-specific viruses, which open the door to future applications that might help controlling the mite through biological control approaches.

microbiology↗

bioRxiv2018

Can herbivore-induced volatiles protect plants by increasing the herbivores’ susceptibility to natural pathogens?

In response to insect herbivory, plants mobilize various defenses. Defense responses include the release of herbivore-induced plant volatiles (HIPVs) that can serve as signals to alert undamaged tissues and to attract natural enemies of the herbivores. It has also been shown that some HIPVs can have a direct negative impact on herbivore survival, but it is not yet understood by what mechanism. Here we tested the hypothesis that exposure to HIPVs renders insects more susceptible to natural pathogens. Exposing caterpillars of the noctuid Spodoptera exigua to indole and linalool, but not exposure to (Z)-3-hexenyl acetate increased the susceptibility to its nucleopolyhedrovirus (SeMNPV). We also found that exposure to indole, but not exposure to linalool or (Z)-3-hexenyl acetate, increased the pathogenicity of Bacillus thuringiensis. Additional experiments revealed significant changes on gut microbiota composition after forty-eight hours of larval exposure to indole. Overall, these results provide evidences that certain HIPVs can strongly enhance the susceptibility of caterpillars to pathogens, possibly through effects on the insects gut microbiota. These findings suggest a novel mechanism by which HIPVs can protect plants from herbivorous insects.

microbiology↗