Biology subjects

Urbaneja, A.

Publications and source records attributed to Urbaneja, A..

5 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↗

bioRxiv2025

Uncovering the genetic basis of fruit volatiles in Fragaria vesca through GWAS reveals FvJMT2 as a methyl benzoate biosynthesis gene with insect-repellent function

Strawberry aroma is a key component of fruit quality, influencing consumer preferences and playing important ecological roles, including plant defense. However, the genetic basis of volatile organic compound (VOC) biosynthesis remains only partially understood, particularly in the wild woodland strawberry Fragaria vesca, which has enormous potential to uncover genetic diversity within the genus for improving the commercial strawberries. Here, we performed Genome-Wide Association Studies (GWAS) across a diverse European collection of F. vesca accessions. We identified multiple novel candidate genes involved in the biosynthesis of diverse volatile esters, lactones, terpenoids, and methyl ketones. Among them, we characterized FvJMT2, a SABATH family methyltransferase which we found associated with natural variation in benzenoid esters content. Transient expression in Nicotiana benthamiana and strawberry fruit confirmed its role in methyl benzoate biosynthesis, while enzymatic assays demonstrated that FvJMT2 encodes a promiscuous enzyme capable of methylating not only benzoic acid, but also cinnamic, salicylic, and jasmonic acids. Behavioral assays revealed that methyl benzoate at physiologically relevant concentrations significantly reduced the attraction of Drosophila suzukii flies, supporting a dual role of this VOC in both flavor and pest deterrence. Finally, natural variation analyses in wild Fragaria species and F. x ananassa cultivars showed that benzenoid esters have been largely lost in modern cultivars but retained in ancient and wild accessions. Altogether, this study provides novel insights into the genetics and ecological relevance of strawberry volatiles and identifies candidate loci and alleles for future studies.

genomics↗

bioRxiv2025

Tamarixia citricola Hansson and Guerrieri sp. nov. (Hymenoptera: Eulophidae): a new parasitoid of Diaphorina citri Kuwayamava (Hemiptera: Psyllidae) found during a classical biological control program in Cyprus

Asian citrus psyllid, Diaphorina citri, is a major global pest because it is the primary vector of Candidatus Liberibacter spp., the causal agents of huanglongbing (HLB), a lethal citrus disease. Following the detection of D. citri in Cyprus in 2023, the first record of this pest in the European Union, a classical biological control program targeting this pest was initiated in spring 2024 using the parasitoid Tamarixia radiata imported from California, USA. During field surveys in summer 2024, parasitized D. citri nymphs were found in orchards where no T. radiata releases had been made. These findings suggested the possible presence of native or unintentionally introduced parasitoids, or a rapid spread of T. radiata into new areas. To determine the identity of parasitoids associated with D. citri in Cyprus, an integrative approach was adopted combining field observations, molecular analyses of the COI gene, and morphological analyses. Tamarixia radiata recovered from Cyprus field sites matched reference sequences of parasitoids from California. However, other specimens were genetically and morphologically distinct and represented a new species. The new species is described here as Tamarixia citricola Hansson & Guerrieri sp. nov. Taxonomic diagnoses and characters for separating both Tamarixia species associated with D. citri are provided. Results presented here indicate the coexistence of both T. radiata (introduced) and T. citricola (likely autochthonous) in Cyprus citrus orchards. This finding has important implications for future biological control strategies and quarantine measures for D. citri in the Mediterranean basin.

zoology↗

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

Jekyll or Hyde? The genome (and more) of Nesidiocoris tenuis, a zoophytophagous predatory bug that is both a biological control agent and a pest

Nesidiocoris tenuis (Reuter) is an efficient predatory biological control agent used throughout the Mediterranean Basin in tomato crops but regarded as a pest in northern European countries. Belonging to the family Miridae, it is an economically important insect yet very little is known in terms of genetic information - no published genome, population studies, or RNA transcripts. It is a relatively small and long-lived diploid insect, characteristics that complicate genome sequencing. Here, we circumvent these issues by using a linked-read sequencing strategy on a single female N. tenuis. From this, we assembled the 355 Mbp genome and delivered an ab initio, homology-based, and evidence-based annotation. Along the way, the bacterial "contamination" was removed from the assembly, which also revealed potential symbionts. Additionally, bacterial lateral gene transfer (LGT) candidates were detected in the N. tenuis genome. The complete gene set is composed of 24,688 genes; the associated proteins were compared to other hemipterans (Cimex lectularis, Halyomorpha halys, and Acyrthosiphon pisum), resulting in an initial assessment of unique and shared protein clusters. We visualised the genome using various cytogenetic techniques, such as karyotyping, CGH and GISH, indicating a karyotype of 2n=32 with a male-heterogametic XX/XY system. Additional analyses include the localization of 18S rDNA and unique satellite probes via FISH techniques. Finally, population genomics via pooled sequencing further showed the utility of this genome. This is one of the first mirid genomes to be released and the first of a mirid biological control agent, representing a step forward in integrating genome sequencing strategies with biological control research.

genomics↗