Investigating the influence of diet diversity on infection outcomes in a bumble bee (Bombus impatiens) and microsporidian (Nosema bombi) host-pathogen system
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PROVIDER: S-EPMC10926413 | biostudies-literature | 2023 Jan
REPOSITORIES: biostudies-literature
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Project description:Pollinators are vital for food security and the maintenance of terrestrial ecosystems. Bumblebees are important pollinators across northern temperate, arctic, and alpine ecosystems, yet are in decline across the globe. Vairimorpha bombi is a parasite belonging to the fungal class Microsporidia that has been implicated in the rapid decline of bumblebees in North America, where it may be an emerging infectious disease. To investigate the evolutionary basis of pathogenicity of V. bombi, we sequenced and assembled its genome using Oxford Nanopore and Illumina technologies and performed phylogenetic and genomic evolutionary analyses. The genome assembly for V. bombi is 4.73 Mb, from which we predicted 1,870 protein-coding genes and 179 tRNA genes. The genome assembly has low repetitive content and low GC content. V. bombi's genome assembly is the smallest of the Vairimorpha and closely related Nosema genera, but larger than those found in the Encephalitozoon and Ordospora sister clades. Orthology and phylogenetic analysis revealed 18 core conserved single-copy microsporidian genes including the histone acetyltransferase (HAT) GCN5. Surprisingly, V. bombi was unique to the microsporidia in not encoding the second predicted HAT ESA1. The V. bombi genome assembly annotation included 265 unique genes (i.e. not predicted in other microsporidia genome assemblies), 20% of which encode a secretion signal, which is a significant enrichment. Intriguingly, of the 36 microsporidian genomes we analyzed, 26 also had a significant enrichment of secreted signals encoded by unique genes, ranging from 6 to 71% of those predicted genes. These results suggest that microsporidia are under selection to generate and purge diverse and unique genes encoding secreted proteins, potentially contributing to or facilitating infection of their diverse hosts. Furthermore, V. bombi has 5/7 conserved spore wall proteins (SWPs) with its closest relative V. ceranae (that primarily infects honeybees), while also uniquely encoding four additional SWPs. This gene class is thought to be essential for infection, providing both environmental protection and recognition and uptake into the host cell. Together, our results show that SWPs and unique genes encoding a secretion signal are rapidly evolving in the microsporidia, suggesting that they underpin key pathobiological traits including host specificity and pathogenicity.
| S-EPMC10989860 | biostudies-literature
Project description:The common Eastern bumble bee Bombus impatiens is native to North America and is the main commercially reared pollinator in the Americas. There has been extensive research on this species related to its social biology, applied pollination, and genetics. The genome of this species was previously sequenced using short-read technology, but recent technological advances provide an opportunity for substantial improvements. This species is common in agricultural and urban environments, and heavy metal contaminants produced by industrial processes can negatively impact it. To begin to identify possible mechanisms underlying responses to these toxins, we used RNA-sequencing to examine how exposure to a cocktail of four heavy metals at field-realistic levels from industrial areas affected B. impatiens worker gene expression.
2024-11-25 | GSE272415 | GEO
Project description:BackgroundThe common Eastern bumble bee Bombus impatiens is native to North America and is the main commercially reared pollinator in the Americas. There has been extensive research on this species related to its social biology, applied pollination, and genetics. The genome of this species was previously sequenced using short-read technology, but recent technological advances provide an opportunity for substantial improvements. This species is common in agricultural and urban environments, and heavy metal contaminants produced by industrial processes can negatively impact it. To begin to identify possible mechanisms underlying responses to these toxins, we used RNA-sequencing to examine how exposure to a cocktail of four heavy metals at field-realistic levels from industrial areas affected B. impatiens worker gene expression.ResultsPacBio long-read sequencing resulted in 544x coverage of the genome, and HiC technology was used to map chromatin contacts. Using Juicer and manual curation, the genome was scaffolded into 18 main pseudomolecules, representing a high quality, chromosome-level assembly. The sequenced genome size is 266.6 Mb and BRAKER3 annotation produced 13,938 annotated genes. The genome and annotation show high completeness, with ≥ 96% of conserved Eukaryota and Hymenoptera genes present in both the assembly and annotated genes. RNA sequencing of heavy metal exposed workers revealed 603 brain and 34 fat body differentially expressed genes. In the brain, differentially expressed genes had biological functions related to chaperone activity and protein folding.ConclusionsOur data represent a large improvement in genomic resources for this important model species-with 10% more genome coverage than previously available, and a high-quality assembly into 18 chromosomes, the expected karyotype for this species. The new gene annotation added 777 new genes. Altered gene expression in response to heavy metal exposure suggests a possible mechanism for how these urban toxins are negatively impacting bee health, specifically by altering protein folding in the brain. Overall, these data are useful as a general high quality genomic resource for this species, and provide insight into mechanisms underlying tissue-specific toxicological responses of bumble bees to heavy metals.
| S-EPMC11575022 | biostudies-literature
Project description:Foraging behavior is a critical adaptation by insects to obtain appropriate nutrients from the environment for development and fitness. Bumble bees (Bombus spp.) form annual colonies which must rapidly increase their worker populations to support rearing reproductive individuals before the end of the season. Therefore, colony growth and reproduction should be dependent on the quality and quantity of pollen resources in the surrounding landscape. Our previous research found that B. impatiens foraging preferences to different plant species were shaped by pollen protein:lipid nutritional ratios (P:L), with foragers preferring pollen species with a ~5:1 P:L ratio. In this study, we placed B. impatiens colonies in three different habitats (forest, forest edge, and valley) to determine whether pollen nutritional quality collected by the colonies differed between areas that may differ in resource abundance and diversity. We found that habitat did not influence the collected pollen nutritional quality, with colonies in all three habitats collecting pollen averaging a 4:1 P:L ratio. Furthermore, there was no difference in the nutritional quality of the pollen collected by colonies that successfully reared reproductives and those that did not. We found however, that "nutritional intake," calculated as the colony-level intake rate of nutrient quantities (protein, lipid, and sugar), was strongly related to colony growth and reproductive output. Therefore, we conclude that B. impatiens colony performance is a function of the abundance of nutritionally appropriate floral resources in the surrounding landscape. Because we did not comprehensively evaluate the nutrition provided by the plant communities in each habitat, it remains to be determined how B. impatiens polylectic foraging strategies helps them select among the available pollen nutritional landscape in a variety of plant communities to obtain a balance of key macronutrients.
| S-EPMC6010792 | biostudies-literature
Project description:In recent years, many pollinators have experienced large population declines, which threaten food security and the stability of natural ecosystems. Bumble bees are particularly important because their ability to "buzz" pollinate and tolerate cooler conditions make them critical pollinators for certain plants and regions. Here, we apply a conservation genomics approach to study the vulnerable Bombus terricola. We sequenced RNA from 30 worker abdomens, 18 of which were collected from agricultural sites and 12 of which were collected from nonagricultural sites. We found transcriptional signatures associated with exposure to insecticides, with gene expression patterns suggesting that bumble bees were exposed to neonicotinoids and/or fipronil-two compounds known to negatively impact bees. We also found transcriptional signatures associated with pathogen infections. In addition to the transcriptomic analysis, we carried out a metatranscriptomic analysis and detected five pathogens in the abdomens of workers, three of which are common in managed honey bee and bumble bee colonies. Our conservation genomics study provides functional support for the role of pesticides and pathogen spillover in the decline of B. terricola. We demonstrate that conservation genomics is an invaluable tool which allows researchers to quantify the effects of multiple stressors that impact pollinator populations in the wild.
| S-EPMC8457087 | biostudies-literature
Project description:Agriculturally important commercially managed pollinators including honey bees (Apis mellifera L., 1758) and bumble bees (Bombus impatiens Cresson, 1863) rely on the surrounding landscape to fulfill their dietary needs. A previous study in Europe demonstrated that managed honey bee foragers and unmanaged native bumble bee foragers are associated with different land uses. However, it is unclear how response to land use compares between managed honey bees and a managed native bumble bee species in the United States, where honey bees are an imported species. Furthermore, to our knowledge, no such direct comparisons of bee responses to land use have been made at the colony level. To better understand how two different social bees respond to variation in land use, we monitored the weights of A. mellifera and B. impatiens colonies placed in 12 apiaries across a range of land use in Michigan, United States in 2017. Bombus impatiens colonies gained more weight and produced more drones when surrounded by diverse agricultural land (i.e., non-corn/soybean cropland such as tree fruits and grapes), while honey bee colonies gained more weight when surrounded by more grassland/pasture land. These findings add to our understanding of how different bee species respond to agricultural landscapes, highlighting the need for further species-specific land use studies to inform tailored land management.
| S-EPMC8452077 | biostudies-literature
Project description:BackgroundDiet and parasitism can have powerful effects on host gene expression. However, how specific dietary components affect host gene expression that could feed back to affect parasitism is relatively unexplored in many wild species. Recently, it was discovered that consumption of sunflower (Helianthus annuus) pollen reduced severity of gut protozoan pathogen Crithidia bombi infection in Bombus impatiens bumble bees. Despite the dramatic and consistent medicinal effect of sunflower pollen, very little is known about the mechanism(s) underlying this effect. However, sunflower pollen extract increases rather than suppresses C. bombi growth in vitro, suggesting that sunflower pollen reduces C. bombi infection indirectly via changes in the host. Here, we analyzed whole transcriptomes of B. impatiens workers to characterize the physiological response to sunflower pollen consumption and C. bombi infection to isolate the mechanisms underlying the medicinal effect. B. impatiens workers were inoculated with either C. bombi cells (infected) or a sham control (un-infected) and fed either sunflower or wildflower pollen ad libitum. Whole abdominal gene expression profiles were then sequenced with Illumina NextSeq 500 technology.ResultsAmong infected bees, sunflower pollen upregulated immune transcripts, including the anti-microbial peptide hymenoptaecin, Toll receptors and serine proteases. In both infected and un-infected bees, sunflower pollen upregulated putative detoxification transcripts and transcripts associated with the repair and maintenance of gut epithelial cells. Among wildflower-fed bees, infected bees downregulated immune transcripts associated with phagocytosis and the phenoloxidase cascade.ConclusionsTaken together, these results indicate dissimilar immune responses between sunflower- and wildflower-fed bumble bees infected with C. bombi, a response to physical damage to gut epithelial cells caused by sunflower pollen, and a strong detoxification response to sunflower pollen consumption. Identifying host responses that drive the medicinal effect of sunflower pollen in infected bumble bees may broaden our understanding of plant-pollinator interactions and provide opportunities for effective management of bee pathogens.
| S-EPMC10053769 | biostudies-literature
Project description:Insects are at the dawn of an epigenetics era. Numerous social insect species have been found to possess a functioning methylation system, previously not thought to exist in insects. Methylation, an epigenetic tag, may be vital for the sociality and division of labour for which social insects are renowned. In the bumble-bee Bombus terrestris, we found methylation differences between the genomes of queenless reproductive workers and queenless non-reproductive workers. In a follow up experiment, queenless workers whose genomes had experimentally altered methylation were more aggressive and more likely to develop ovaries compared with control queenless workers. This shows methylation is important in this highly plastic reproductive division of labour. Methylation is an epigenetic tag for genomic imprinting (GI). It is intriguing that the main theory to explain the evolution of GI predicts that GI should be important in this worker reproduction behaviour.
| S-EPMC4027386 | biostudies-literature
Project description:Cuckoo bumble bees (Psithyrus) (Lepeletier, 1832) (Hymenoptera: Apidae) are a unique lineage of bees that depend exclusively on a host bumble bee species to provide nesting material, nutritional resources, and labor to rear offspring. In this study, we document usurpation incidence and population genetic data of Bombus insularis (Smith, 1861) (Hymenoptera: Apidae), a bumble bee species in the Psithyrus subgenus, on field-deployed B. huntii colonies in northern Utah, United States. Within 12 d of deploying B. huntii Greene, 1860 (Hymenoptera: Apidae) colonies at two field sites, 13 of the 16 colonies contained at least one established B. insularis female. Although our results demonstrate that field-deployed bumble bee colonies are highly susceptible to B. insularis usurpation, applying a fabricated excluder to prevent the inquiline from invading a colony was 100% effective. Sibship analysis using microsatellite genotype data of 59 B. insularis females estimates that they originated from at least 49 unique colonies. Furthermore, sibship analysis found siblings distributed between the field sites that were 7.04 km apart. Our result suggests that B. insularis females have the capacity to disperse across the landscape in search of host colonies at distances of at least 3.52 km and up to 7.04 km. Our study underscores the detrimental impact B. insularis usurpation has on the host bumble bee colony. As B. insularis significantly impacts the success of bumble bee colonies, we briefly discuss how the utilization of excluders may be useful for commercial bumble bee colonies that are used to pollinate open field crops.
| S-EPMC8415179 | biostudies-literature
Project description:BackgroundIn Canada, the Common Eastern Bumble Bee (Bombus impatiens Cresson) is native to southern Ontario and Quebec, but since being developed as a managed commercial pollinator, it has been exported to several other provinces for use in greenhouse and field crop settings. This has enabled this species to become established outside its natural range and it is now established in eastern Canada (New Brunswick, Nova Scotia, Prince Edward Island) and British Columbia. To date, the species has not been detected via field capture in the prairie provinces.New informationHere we report on recent captures of B. impatiens workers and males from south-eastern Alberta and suggest that these specimens escaped from nearby commercial greenhouses. The risk that the presence and looming establishment of this species has on native bumble bees in the Canadian prairies is discussed.
| S-EPMC6356050 | biostudies-literature