Biology subjects

De Smet, L.

Publications and source records attributed to De Smet, L..

3 recordsLinked to original sources

bioRxiv2026

A Putative Single-Locus Determinant of the Suppressed In Ovo Virus Infection (SOV) Trait in Apis mellifera

Today, the deformed wing virus (DWV) can be considered as one of the major causes of global elevated western honey bee colony losses (Apis mellifera). Virus transmission may occur horizontally between individuals of the same generation, but also vertically from parents to offspring. The recently defined heritable suppressed in ovo virus infection (SOV) trait describes the absence of viruses in pooled drone eggs of a queen, associated with significant lower DWV prevalence and viral loads in the subsequent developmental offspring stages. By definition, the trait reflects the absence of vertical virus transmission from SOV-positive (SOV+) queens themselves to their offspring. However, the genetic basis influencing this heritable virus resilience has not been identified yet. In this study, we aimed to identify SOV-associated genetic marker(s) or loci in the honey bee genome through genome-wide variant comparison of 44 DWV-positive and 44 DWV-negative drone pupae descendent from an artificially created hybrid SOV+/SOV- colony. After whole genome sequencing (WGS), variant calling, and genotype-phenotype association analysis by means of single marker tests and elastic net regression, one variant in a locus of 241.246 bp on chromosome 7 that contained 17 other highly SOV-associated variants classified 68,2% of the drone phenotypes correctly. These results may support the potential application of marker-assisted selection (MAS) strategies targeting reduced vertical virus transmission in honey bees.

genomics↗

bioRxiv2026

Genetic Diversity of Cytochrome P450 Genes in Apis mellifera Subspecies

The western honey bee (Apis mellifera) is an essential pollinator facing unprecedented threats from pesticide exposure. While pesticide resistance evolution is well documented in agricultural pests, our understanding of genetic variation in honey bee detoxification systems remains limited. This represents a missed opportunity, as harnessing naturally occurring detoxification diversity could provide new avenues for pollinator protection. Cytochrome P450 monooxygenases (CYPs), which are central to xenobiotic metabolism, offer a promising starting point. Here, we present the first comprehensive analysis of CYP genetic diversity in A. mellifera. We analysed the CYPome of 1,467 individuals representing 18 A. mellifera subspecies from 25 countries and identified 5,756 single-nucleotide polymorphisms (SNPs) in 46 CYP genes. Imputed McDonald-Kreitman testing revealed that 56% of non-synonymous CYP substitutions were driven by positive selection. Of the 1,302 haplotypes identified, 84% resided in CYP3, concentrated in the CYP9 and CYP6AS subfamilies implicated in xenobiotic detoxification. Population-level analysis of nucleotide diversity, Tajimas D selection signatures, FST-based differentiation, and McDonald-Kreitman testing pointed to CYP3 clan genes as the primary locus of adaptive variation. This work provides the first step toward building a comprehensive pharmacogenomic resource for honey bees, enabling the prediction of population-specific pesticide vulnerabilities and leveraging naturally occurring detoxification variants to enhance pollinator resilience - a critical step toward sustainable pollinator management.

genomics↗

bioRxiv2022

Dynamics in vertical transmission of viruses in naturally selected and traditionally managed honey bee colonies across Europe

The suppressed in-ovo virus infection trait (SOV) was the first trait applied in honey bee breeding programs aimed to increase resilience to virus infections, a major threat for colony survival. By screening drone eggs for viruses, the SOV trait scores the antiviral resistance of queens and its implications for vertical transmission. In this study, queens from both naturally surviving and traditionally managed colonies from across Europe were screened using a two-fold improved SOV phenotyping protocol. First, a gel-based RT-PCR was replaced by a RT-qPCR. This not only allowed quantification of the infection load but also increased the test sensitivity. Second, a genotype specific primer set was replaced by a primer set that covered all known deformed wing virus (DWV) genotypes, which resulted in higher virus loads and fewer false negative results. It was demonstrated that incidences of vertical transmission of DWV were more frequent in naturally surviving populations than in traditionally managed colonies, although the virus load in the eggs remained the same. Dynamics in vertical transmission were further emphasized when comparing virus infections with queen age. Interestingly, older queens showed significantly lower infection loads of DWV in both traditionally managed and naturally surviving colonies, as well as reduced DWV infection frequencies in traditionally managed colonies when compared with younger queens. Seasonal variation in vertical transmission was found with lower infection frequencies in spring compared to summer for DWV and black queen cell virus. Together, these patterns in vertical transmission suggest an adaptive antiviral response of queens aimed at reducing vertical transmission over time.

ecology↗