Browsing by Author "Flenniken, Michelle L."

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Abiotic and biotic factors affecting the replication and pathogenicity of bee viruses
(2016-04) McMenamin, Alexander J.; Brutscher, Laura M.; Glenny, William; Flenniken, Michelle L.
Bees are important pollinators of plants in both agricultural and non-agricultural landscapes. Recent losses of both managed and wild bee species have negative impacts on crop production and ecosystem diversity. Therefore, in order to mitigate bee losses, it is important to identify the factors most responsible. Multiple factors including pathogens, agrochemical exposure, lack of quality forage, and reduced habitat affect bee health. Pathogen prevalence is one factor that has been associated with colony losses. Numerous pathogens infect bees including fungi, protists, bacteria, and viruses, the majority of which are RNA viruses including several that infect multiple bee species. RNA viruses readily infect bees, yet there is limited understanding of their impacts on bee health, particularly in the context of other stressors. Herein we review the influence environmental factors have on the replication and pathogenicity of bee viruses and identify research areas that require further investigation.
Acute Toxicity of Permethrin, Deltamethrin, and Etofenprox to the Alfalfa Leafcutting Bee
(2018-05) Piccolomini, Alyssa M.; Whiten, Shavonn R.; Flenniken, Michelle L.; O'Neill, Kevin M.; Peterson, Robert K. D.
Current regulatory requirements for insecticide toxicity to nontarget insects focus on the honey bee, Apis mellifera (L.; Hymenoptera: Apidae), but this species cannot represent all insect pollinator species in terms of response to insecticides. Therefore, we characterized the toxicity of pyrethroid insecticides used for adult mosquito management (permethrin, deltamethrin, and etofenprox) on a nontarget insect, the adult alfalfa leafcutting bee, Megachile rotundata (F.; Hymenoptera: Megachilidae) in two separate studies. In the first study, the doses causing 50 and 90% mortality (LD50 and LD90, respectively) were used as endpoints and 2-d-old adult females were exposed to eight concentrations ranging from 0.0075 to 0.076 μg/bee for permethrin and etofenprox, and 0.0013–0.0075 μg/bee for deltamethrin. For the second study, respiration rates of female M. rotundata were also recorded for 2 h after bees were dosed at the LD50 values to give an indication of stress response. Results indicated a relatively similar LD50 for permethrin and etofenprox, 0.057 and 0.051 μg/bee, respectively, and a more toxic response, 0.0016 μg/bee for deltamethrin. Comparatively, female A. mellifera workers have a LD50 value of 0.024 μg/bee for permethrin and 0.015 μg/bee for etofenprox indicating that female M. rotundata are less susceptible to topical doses of these insecticides, except for deltamethrin, where both A. mellifera and M. rotundata have an identical LD50 of 0.0016 μg/bee. Respiration rates comparing each active ingredient to control groups, as well as rates between each active ingredient, were statistically different (P < 0.0001). The addition of these results to existing information on A. mellifera may provide more insights on how other economically beneficial and nontarget bees respond to pyrethroids.
Antiviral Defense in Invertebrates
(2018-08) Flenniken, Michelle L.
Invertebrate organisms include vectors of human viruses (mosquitoes, sand flies), model organisms (fruit fly), insect pollinators (honey bees and bumble bees), plant virus vectors (aphids), and commercially valuable aquatic species (oysters and shrimp) that play important roles in shaping ecosystems throughout the world. Like all organisms, invertebrates are infected by viruses and have, in turn, evolved strategies to limit virus infection. There are some fundamental similarities in host defense mechanisms, including the host recognition of non-self, pathogen-associated molecular patterns (e.g., viral dsRNA) that in turn stimulate the activation of host proteins, and expression of genes required to restrict virus replication, as well as unique aspects of specific hostâ€“virus interactions that are a result of co-evolution. Invertebrate antiviral defense mechanisms include canonical immune signaling cascades (e.g., Jak/STAT, Toll, Imd), heat shock responses, apoptosis, and dsRNA-triggered responses including the sequence-specific RNA interference mechanism and a less well characterized, non-sequence-specific dsRNA mediated response.
Antiviral Defense Mechanisms in Honey Bees
(2015-08) Brutscher, Laura M.; Daughenbaugh, Katie F.; Flenniken, Michelle L.
Honey bees are significant pollinators of agricultural crops and other important plant species. High annual losses of honey bee colonies in North America and in some parts of Europe have profound ecological and economic implications. Colony losses have been attributed to multiple factors including RNA viruses, thus understanding bee antiviral defense mechanisms may result in the development of strategies that mitigate colony losses. Honey bee antiviral defense mechanisms include RNA-interference, pathogen-associated molecular pattern (PAMP) triggered signal transduction cascades, and reactive oxygen species generation. However, the relative importance of these and other pathways is largely uncharacterized. Herein we review the current understanding of honey bee antiviral defense mechanisms and suggest important avenues for future investigation.
Biodistribution studies of protein cage nanoparticles demonstrate broad tissue distribution and rapid clearance in vivo
(2007-12) Kaiser, Coleen R.; Flenniken, Michelle L.; Gillitzer, Eric; Harmsen, Ann L.; Harmsen, Allen G.; Jutila, Mark A.; Douglas, Trevor; Young, Mark J.
Protein cage nanoparticles have the potential to serve as multifunctional cell targeted, imaging and therapeutic platforms for broad applications in medicine. However, before they find applications in medicine, their biocompatibility in vivo needs to be demonstrated. We provide here baseline biodistribution information of two different spherical protein cage nanoplatforms, the 28 nm viral Cowpea chlorotic mottle virus (CCMV) and the 12 nm heat shock protein (Hsp) cage. In naïve and immunized mice both nanoplatforms show similar broad distribution and movement throughout most tissues and organs, rapid excretion, the absence of long term persistence within mice tissue and organs, and no overt toxicity after a single injection. These results suggest that protein cage based nanoparticles may serve as safe, biocompatible, nanoplatforms for applications in medicine.
Chemical Stimulants and Stressors Impact the Outcome of Virus Infection and Immune Gene Expression in Honey Bees (Apis mellifera)
(Frontiers Media SA, 2021-10) Parekh, Fenali; Daughenbaugh, Katie F.; Flenniken, Michelle L.
Western honey bees (Apis mellifera) are ecologically, agriculturally, and economically important plant pollinators. High average annual losses of honey bee colonies in the US have been partially attributed to agrochemical exposure and virus infections. To examine the potential negative synergistic impacts of agrochemical exposure and virus infection, as well as the potential promise of phytochemicals to ameliorate the impact of pathogenic infections on honey bees, we infected bees with a panel of viruses (i.e., Flock House virus, deformed wing virus, or Sindbis virus) and exposed to one of three chemical compounds. Specifically, honey bees were fed sucrose syrup containing: (1) thyme oil, a phytochemical and putative immune stimulant, (2) fumagillin, a beekeeper applied fungicide, or (3) clothianidin, a grower-applied insecticide. We determined that virus abundance was lower in honey bees fed 0.16 ppb thyme oil augmented sucrose syrup, compared to bees fed sucrose syrup alone. Parallel analysis of honey bee gene expression revealed that honey bees fed thyme oil augmented sucrose syrup had higher expression of key RNAi genes (argonaute-2 and dicer-like), antimicrobial peptide expressing genes (abaecin and hymenoptaecin), and vitellogenin, a putative honey bee health and age indicator, compared to bees fed only sucrose syrup. Virus abundance was higher in bees fed fumagillin (25 ppm or 75 ppm) or 1 ppb clothianidin containing sucrose syrup relative to levels in bees fed only sucrose syrup. Whereas, honey bees fed 10 ppb clothianidin had lower virus levels, likely because consuming a near lethal dose of insecticide made them poor hosts for virus infection. The negative impact of fumagillin and clothianidin on honey bee health was indicated by the lower expression of argonaute-2, dicer-like, abaecin, and hymenoptaecin, and vitellogenin. Together, these results indicate that chemical stimulants and stressors impact the outcome of virus infection and immune gene expression in honey bees.
A draft genome of the honey bee trypanosomatid parasite Crithidia mellificae
(2014-04) Runckel, Charles; DeRisi, Joseph; Flenniken, Michelle L.
Since 2006, honey bee colonies in North America and Europe have experienced increased annual mortality. These losses correlate with increased pathogen incidence and abundance, though no single etiologic agent has been identified. Crithidia mellificae is a unicellular eukaryotic honey bee parasite that has been associated with colony losses in the USA and Belgium. C. mellificae is a member of the family Trypanosomatidae, which primarily includes other insect-infecting species (e.g., the bumble bee pathogen Crithidia bombi), as well as species that infect both invertebrate and vertebrate hosts including human pathogens (e.g.,Trypanosoma cruzi, T. brucei, and Leishmania spp.). To better characterize C. mellificae, we sequenced the genome and transcriptome of strain SF, which was isolated and cultured in 2010. The 32 megabase draft genome, presented herein, shares a high degree of conservation with the related species Leishmania major. We estimate that C. mellificae encodes over 8,300 genes, the majority of which are orthologs of genes encoded by L. major and other Leishmania or Trypanosoma species. Genes unique to C. mellificae, including those of possible bacterial origin, were annotated based on function and include genes putatively involved in carbohydrate metabolism. This draft genome will facilitate additional investigations of the impact of C. mellificae infection on honey bee health and provide insight into the evolution of this unique family.
Effects of an Ultra-low-Volume Application of Etofenprox for Mosquito Management on Megachile rotundata (Hymenoptera: Megachilidae) Larvae and Adults in an Agricultural Setting
(2018-02) Piccolomini, Alyssa M.; Flenniken, Michelle L.; O'Neill, Kevin M.; Peterson, Robert K. D.
The alfalfa leafcutting bee, Megachile rotundata F. (Hymenoptera: Megachilidae), is one of the most intensively managed solitary bees and greatly contributes to alfalfa production in both the United States and Canada. Although production of certain commodities, especially alfalfa seed, has become increasingly dependent on this species\' pollination proficiency, little information is known about how M. rotundata is affected by insecticide exposure. To better understand the risk posed to M. rotundata by the increasing use of insecticides to manage mosquitoes, we conducted field experiments that directly exposed M. rotundata nests, adults, and larvae to a pyrethroid insecticide via a ground-based ultra-low-volume (ULV) aerosol generator. We directly targeted nest shelters with Zenivex E20 (etofenprox) at a half-maximum rate of 0.0032 kg/ha at dusk and then observed larval mortality, adult mortality, and the total number of completed nests for both the treated and control groups. There was no significant difference in the proportion of dead (P = 0.99) and alive (P = 0.23) larvae when the control group was compared with the treated group. We also did not observe a significant difference in the number of emerged adults reared from the treated shelters (P = 0.22 and 0.50 for females and males, respectively), and the number of completed cells after exposure to the insecticides continued to increase throughout the summer, indicating that provisioning adults were not affected by the insecticide treatment. The results from this study suggest that the amount of insecticide reaching nest shelters may not be sufficient to cause significant mortality.
Honey bee (Apis mellifera) colony health and pathogen composition in migratory beekeeping operations involved in California almond pollination
(2017-08) Glenny, William; Cavigli, Ian; Daughenbaugh, Katie F.; Radford, Rosemarie; Kegley, Susan E.; Flenniken, Michelle L.
Honey bees are important pollinators of agricultural crops. Pathogens and other factors have been implicated in high annual losses of honey bee colonies in North America and some European countries. To further investigate the relationship between multiple factors, including pathogen prevalence and abundance and colony health, we monitored commercially managed migratory honey bee colonies involved in California almond pollination in 2014. At each sampling event, honey bee colony health was assessed, using colony population size as a proxy for health, and the prevalence and abundance of seven honey bee pathogens was evaluated using PCR and quantitative PCR, respectively. In this sample cohort, pathogen prevalence and abundance did not correlate with colony health, but did correlate with the date of sampling. In general, pathogen prevalence (i.e., the number of specific pathogens harbored within a colony) was lower early in the year (January-March) and was greater in the summer, with peak prevalence occurring in June. Pathogen abundance in individual honey bee colonies varied throughout the year and was strongly associated with the sampling date, and was influenced by beekeeping operation, colony health, and mite infestation level. Together, data from this and other observational cohort studies that monitor individual honey bee colonies and precisely account for sampling date (i.e., day of year) will lead to a better understanding of the influence of pathogens on colony mortality and the effects of other factors on these associations.
Honey Bee and Bumble Bee Antiviral Defense
(2018-08) McMenamin, Alexander J.; Daughenbaugh, Katie F.; Parekh, Fenali; Pizzorno, Marie C.; Flenniken, Michelle L.
Bees are important plant pollinators in both natural and agricultural ecosystems. Managed and wild bees have experienced high average annual colony losses, population declines, and local extinctions in many geographic regions. Multiple factors, including virus infections, impact bee health and longevity. The majority of bee-infecting viruses are positive-sense single-stranded RNA viruses. Bee-infecting viruses often cause asymptomatic infections but may also cause paralysis, deformity or death. The severity of infection is governed by bee host immune responses and influenced by additional biotic and abiotic factors. Herein, we highlight studies that have contributed to the current understanding of antiviral defense in bees, including the Western honey bee (Apis mellifera), the Eastern honey bee (Apis cerana) and bumble bee species (Bombus spp.). Bee antiviral defense mechanisms include RNA interference (RNAi), endocytosis, melanization, encapsulation, autophagy and conserved immune pathways including Jak/STAT (Janus kinase/signal transducer and activator of transcription), JNK (c-Jun N-terminal kinase), MAPK (mitogen-activated protein kinases) and the NF-ÎºB mediated Toll and Imd (immune deficiency) pathways. Studies in Dipteran insects, including the model organism Drosophila melanogaster and pathogen-transmitting mosquitos, provide the framework for understanding bee antiviral defense. However, there are notable differences such as the more prominent role of a non-sequence specific, dsRNA-triggered, virus limiting response in honey bees and bumble bees. This virus-limiting response in bees is akin to pathways in a range of organisms including other invertebrates (i.e., oysters, shrimp and sand flies), as well as the mammalian interferon response. Current and future research aimed at elucidating bee antiviral defense mechanisms may lead to development of strategies that mitigate bee losses, while expanding our understanding of insect antiviral defense and the potential evolutionary relationship between sociality and immune function.
Honey Bee Infecting “Plant Virus” with Implications on Honey Bee Colony Health
(2014-02) Flenniken, Michelle L.
Honey bees are eusocial insects that are commercially managed to provide pollination services for agricultural crops. Recent increased losses of honey bee colonies (averaging 32% annually since 2006) are associated with the incidence and abundance of pathogens. In their study in mBio, J. L. Li et al. [mBio 5(1):e00898-13, 2014, doi:10.1128/mBio.00898-13] share their discovery that a plant virus, tobacco ring spot virus (TRSV), replicates in honey bees and that the prevalence of this virus was high in weak colonies. Their findings increase our understanding of the role of viruses in honey bee colony losses and underscore the importance of surveying for new and/or emerging viruses in honey bees. Furthermore, their findings will pique the interest of virologists and biologists across all disciplines. The discovery that a plant virus (TRSV) replicates, spreads, and negatively affects the health of an insect host will lead to additional studies on the mechanisms of host-specific adaptation and the role of cross-kingdom infections in the transmission of this virus.
Honey bee infecting Lake Sinai viruses
(2015-06) Daughenbaugh, Katie F.; Martin, Madison; Brutscher, Laura M.; Cavigli, Ian; Garcia, Emma; Lavin, Matthew; Flenniken, Michelle L.
Honey bees are critical pollinators of important agricultural crops. Recently, high annual losses of honey bee colonies have prompted further investigation of honey bee infecting viruses. To better characterize the recently discovered and very prevalent Lake Sinai virus (LSV) group, we sequenced currently circulating LSVs, performed phylogenetic analysis, and obtained images of LSV2. Sequence analysis resulted in extension of the LSV1 and LSV2 genomes, the first detection of LSV4 in the US, and the discovery of LSV6 and LSV7. We detected LSV1 and LSV2 in the Varroa destructor mite, and determined that a large proportion of LSV2 is found in the honey bee gut, suggesting that vector-mediated, food-associated, and/or fecal-oral routes may be important for LSV dissemination. Pathogen-specific quantitative PCR data, obtained from samples collected during a small-scale monitoring project, revealed that LSV2, LSV1, Black queen cell virus (BQCV), and Nosema ceranae were more abundant in weak colonies than strong colonies within this sample cohort. Together, these results enhance our current understanding of LSVs and illustrate the importance of future studies aimed at investigating the role of LSVs and other pathogens on honey bee health at both the individual and colony levels.
Investigating Virus–Host Interactions in Cultured Primary Honey Bee Cells
(MDPI AG, 2021-07) McMenamin, Alexander J.; Parekh, Fenali; Lawrence, Verena; Flenniken, Michelle L.
Honey bee (Apis mellifera) health is impacted by viral infections at the colony, individual bee, and cellular levels. To investigate honey bee antiviral defense mechanisms at the cellular level we further developed the use of cultured primary cells, derived from either larvae or pupae, and demonstrated that these cells could be infected with a panel of viruses, including common honey bee infecting viruses (i.e., sacbrood virus (SBV) and deformed wing virus (DWV)) and an insect model virus, Flock House virus (FHV). Virus abundances were quantified over the course of infection. The production of infectious virions in cultured honey bee pupal cells was demonstrated by determining that naïve cells became infected after the transfer of deformed wing virus or Flock House virus from infected cell cultures. Initial characterization of the honey bee antiviral immune responses at the cellular level indicated that there were virus-specific responses, which included increased expression of bee antiviral protein-1 (GenBank: MF116383) in SBV-infected pupal cells and increased expression of argonaute-2 and dicer-like in FHV-infected hemocytes and pupal cells. Additional studies are required to further elucidate virus-specific honey bee antiviral defense mechanisms. The continued use of cultured primary honey bee cells for studies that involve multiple viruses will address this knowledge gap.
Longitudinal monitoring of honey bee colonies reveals dynamic nature of virus abundance and indicates a negative impact of Lake Sinai virus 2 on colony health
(2020-09) Faurot-Daniels, Cayley; Glenny, William; Daughenbaugh, Katie F.; McMenamin, Alexander J.; Burkle, Laura A.; Flenniken, Michelle L.
Honey bees (Apis mellifera) are important pollinators of plants, including those that produce nut, fruit, and vegetable crops. Therefore, high annual losses of managed honey bee colonies in the United States and many other countries threaten global agriculture. Honey bee colony deaths have been associated with multiple abiotic and biotic factors, including pathogens, but the impact of virus infections on honey bee colony population size and survival are not well understood. To further investigate seasonal patterns of pathogen presence and abundance and the impact of viruses on honey bee colony health, commercially managed colonies involved in the 2016 California almond pollination event were monitored for one year. At each sample date, colony health and pathogen burden were assessed. Data from this 50-colony cohort study illustrate the dynamic nature of honey bee colony health and the temporal patterns of virus infection. Black queen cell virus, deformed wing virus, sacbrood virus, and the Lake Sinai viruses were the most readily detected viruses in honey bee samples obtained throughout the year. Analyses of virus prevalence and abundance revealed pathogen-specific trends including the overall increase in deformed wing virus abundance from summer to fall, while the levels of Lake Sinai virus 2 (LSV2) decreased over the same time period. Though virus prevalence and abundance varied in individual colonies, analyses of the overall trends reveal correlation with sample date. Total virus abundance increased from November 2015 (post-honey harvest) to the end of the almond pollination event in March 2016, which coincides with spring increase in colony population size. Peak total virus abundance occurred in late fall (August and October 2016), which correlated with the time period when the majority of colonies died. Honey bee colonies with larger populations harbored less LSV2 than weaker colonies with smaller populations, suggesting an inverse relationship between colony health and LSV2 abundance. Together, data from this and other longitudinal studies at the colony level are forming a better understanding of the impact of viruses on honey bee colony losses.
Longitudinal monitoring of honey bee colonies reveals dynamic nature of virus abundance and indicates a negative impact of Lake Sinai virus 2 on colony health
(Public Library of Science, 2020-09) Faurot-Daniels, Cayley; Glenny, William; Daughenbaugh, Katie F.; McMenamin, Alexander J.; Burkle, Laura A.; Flenniken, Michelle L.
Honey bees (Apis mellifera) are important pollinators of plants, including those that produce nut, fruit, and vegetable crops. Therefore, high annual losses of managed honey bee colonies in the United States and many other countries threaten global agriculture. Honey bee colony deaths have been associated with multiple abiotic and biotic factors, including pathogens, but the impact of virus infections on honey bee colony population size and survival are not well understood. To further investigate seasonal patterns of pathogen presence and abundance and the impact of viruses on honey bee colony health, commercially managed colonies involved in the 2016 California almond pollination event were monitored for one year. At each sample date, colony health and pathogen burden were assessed. Data from this 50-colony cohort study illustrate the dynamic nature of honey bee colony health and the temporal patterns of virus infection. Black queen cell virus, deformed wing virus, sacbrood virus, and the Lake Sinai viruses were the most readily detected viruses in honey bee samples obtained throughout the year. Analyses of virus prevalence and abundance revealed pathogen-specific trends including the overall increase in deformed wing virus abundance from summer to fall, while the levels of Lake Sinai virus 2 (LSV2) decreased over the same time period. Though virus prevalence and abundance varied in individual colonies, analyses of the overall trends reveal correlation with sample date. Total virus abundance increased from November 2015 (post-honey harvest) to the end of the almond pollination event in March 2016, which coincides with spring increase in colony population size. Peak total virus abundance occurred in late fall (August and October 2016), which correlated with the time period when the majority of colonies died. Honey bee colonies with larger populations harbored less LSV2 than weaker colonies with smaller populations, suggesting an inverse relationship between colony health and LSV2 abundance. Together, data from this and other longitudinal studies at the colony level are forming a better understanding of the impact of viruses on honey bee colony losses.
Melanoma and Lymphocyte Cell Specific Targeting Incorporated into a Heat Shock Protein Cage Architecture
(2006) Flenniken, Michelle L.; Willits, Deborah A.; Harmsen, Ann L.; Liepold, Lars O.; Harmsen, Allen G.; Young, Mark J.; Douglas, Trevor
Protein cages, including viral capsids, ferritins, and heat shock proteins (Hsps), can serve as nanocontainers for biomedical applications. They are genetically and chemically malleable platforms, with potential as therapeutic and imaging agent delivery systems. Here, both genetic and chemical strategies were used to impart cell-specific targeting to the Hsp cage from Methanococcus jannaschii. A tumor vasculature targeting peptide was incorporated onto the exterior surface of the Hsp cage. This protein cage bound to αvβ3 integrin-expressing cells. Cellular tropism was also imparted by conjugating anti-CD4 antibodies to the exterior of Hsp cages. These Ab-Hsp cage conjugates specifically bound to CD4+ cells. Protein cages have the potential to simultaneously incorporate multiple functionalities, including cell-specific targeting, imaging, and therapeutic agent delivery. We demonstrate the simultaneous incorporation of two functionalities, imaging and cell-specific targeting, onto the Hsp protein cage.
Microbe manufacturers of semiconductors
(2004-11) Flenniken, Michelle L.; Allen, Mark; Douglas, Trevor
Synthesis of cadmium sulfide (CdS) semiconductor nanoparticles within a prokaryotic organism is reported for the first time by Sweeney et al. [1]. This paper demonstrates the utility of microorganisms to perform chemistries outside the scope of their “normal” metabolism and offers an environmentally benign synthesis of CdS nanoparticles.
Non-specific dsRNA-Mediated Innate Immune Response in the Honey Bee
(2013-10) Flenniken, Michelle L.; Andino, Raul
Honey bees are essential pollinators of numerous agricultural crops. Since 2006, honey bee populations have suffered considerable annual losses that are partially attributed to Colony Collapse Disorder (CCD). CCD is an unexplained phenomenon that correlates with elevated incidence of pathogens, including RNA viruses. Honey bees are eusocial insects that live in colonies of genetically related individuals that work in concert to gather and store nutrients. Their social organization provides numerous benefits, but also facilitates pathogen transmission between individuals. To investigate honey bee antiviral defense mechanisms, we developed an RNA virus infection model and discovered that administration of dsRNA, regardless of sequence, reduced virus infection. Our results suggest that dsRNA, a viral pathogen associated molecular pattern (PAMP), triggers an antiviral response that controls virus infection in honey bees.
Pathogen prevalence and abundance in honey bee colonies involved in almond pollination
(2016-03) Cavigli, Ian; Daughenbaugh, Katie F.; Martin, Madison; Lerch, Michael D.; Banner, Katharine M.; Garcia, Emma; Brutscher, Laura M.; Flenniken, Michelle L.
Honey bees are important pollinators of agricultural crops. Since 2006, US beekeepers have experienced high annual honey bee colony losses, which may be attributed to multiple abiotic and biotic factors, including pathogens. However, the relative importance of these factors has not been fully elucidated. To identify the most prevalent pathogens and investigate the relationship between colony strength and health, we assessed pathogen occurrence, prevalence, and abundance in Western US honey bee colonies involved in almond pollination. The most prevalent pathogens were Black queen cell virus (BQCV), Lake Sinai virus 2 (LSV2), Sacbrood virus (SBV), Nosema ceranae, and trypanosomatids. Our results indicated that pathogen prevalence and abundance were associated with both sampling date and beekeeping operation, that prevalence was highest in honey bee samples obtained immediately after almond pollination, and that weak colonies had a greater mean pathogen prevalence than strong colonies.
Potato Cultivar and Seed Type Affect the Development of Systemic Potato virus Infection
(2018-04) Boyd, Elisa K.; Carpenter, Eileen; Ross, Brian T.; Zidack, Nina; Flenniken, Michelle L.
Potato virus Y (PVY) infection is one of the greatest challenges to seed potato production in the United States. To determine how cultivar and seed type affect the development of systemic PVY infection, Russet Burbank and Russet Norkotah Colorado 3 cultivars were grown from two types of pre-nuclear seed (i.e., plantlets and minitubers) and Generation 3 (G3) tubers and challenged with PVY strain Wilga (PVYN-Wi). Systemic PVY infection was measured by assaying spread of virus from the inoculation site to upper non-inoculated leaves. The Burbank cultivar had a lower incidence of systemic PVY infection compared to the incidence of systemic PVY that developed in the Colorado 3 cultivar. Furthermore, Burbank plants grown from G3 tubers had a lower incidence of systemic PVY infection, as compared to Burbank plants grown from plantlets. Together our results indicate that both cultivar and seed type affect the development of systemic PVYN-Wi infections post-inoculation.