Project description:As a matter of fact, honeybees are vital for the pollination of more than 80 crops of agricultural interest. However, population decline has become an important global issue causing significant concerns among agricultural experts and the broader public. For this, parasites are known to be the major culprits responsible for the losses of millions of honeybee colonies so far. Among these parasites, Varroa destructor has been identified as a major cause for global losses in Western honeybee (Apis mellifera) colonies. Hygienic behavior (HB), on the other hand, is a collective response by adult honeybees to defend against parasites and diseases that is known to involve in resistance towards Varroosis. Even with the efforts made to elucidate the molecular mechanism underlying HB, it is still not understood. In our study, we have studied the proteomic correlates to HB using a honeybee line (selected for Varroa-specific HB for over a decade in Germany). We sampled individual worker bees from this line that showed HB after closer infrared video observations and compared the proteomes of their mushroom bodies and antennae with those of workers that came from the same set of colonies but didn't show the behaviour. Furthermore, we compared the pupal hemolymph for worker bees of the selected HB line and a control line using state-of-the art techniques of proteomics. We identified a total of 8609 proteins (covered >55% of the honeybee proteome) from these three honeybee tissues. This is the most comprehensive proteomic study of the honeybee HB to date, and the first to focus on individual bees expressing Varroa-specific HB. These results have significantly advanced our knowledge on the biology underlining HB to a new level. The uniquely found functional classes and pathways by the proteins identified in each tissue suggest that hygienic bees have shaped distinct proteome settings to underpin the HB. Moreover, during analysis of pupal hemolymph proteome, the HB-line has adapted a unique strategy to boost an individual and social immunity and drove pupal organogenesis via energy metabolism and protein biosynthesis. Moreover, in the mushroom bodies of different HB phenotypic worker bees, the hygienic bees have enhanced their neuronal sensitivity to promote the execution of HB by activation of synaptic vesicles and calcium channel activities. Moreover, in the antennae of two HB phenotypic worker bees, the hygienic bees have demonstrated strengthening of their sensitivity associated with olfactory senses and signal transmissions, which is important to input a strong signal to the mushroom bodies and initiate HB. In conclusion, our novel findings have significantly extended our understandings of the molecular mechanisms that underline the HB to combat Varroa infestation. Furthermore, we identified a wide array of novel markers that are useful for accelerating marker associated selection of HB to aid in the natural resistance to a parasite blamed for a global decline in honeybee health.
Project description:We characterized and compared hemolymph proteome of Royal Jelly bees (RJbs), a stock selected for increasing RJ output from Italian bees (ITbs) and ITbs across the larval and adult ages. Unprecedented depth of proteome was attained by identifying 3394 hemolymph proteins in both bee lines. The proteome supports the general function of hemolymph to drive development and immunity across different phases in both bees. However, age-specific proteome settings have adapted to prime the distinct physiology for larvae and adult bees. In larvae, proteome are thought to drive the temporal immunity, rapid organogenesis, and reorganization of larval structures. In adults, proteome play key roles to prompt tissues development and immune defense in NEBs, glands maturity in NBs and carbohydrate energy production in FBs. Comparing the proteome between the same aged larval and adult samples, RJbs and ITbs have tailored distinct hemolymph proteome programs to drive their physiology. Particularly, in day 4 larvae and NBs, a large number of highly abundant proteins enriched in protein synthesis and energy metabolism in RJbs relative to ITbs imply that RJb larvae and NBs have reprogrammed their proteome to initiate different developmental trajectory and high RJ secretion in response to the enhanced RJ production by selection. Our hitherto depth of proteome coverage gains novel sight on molecular details in driving hemolymph function and high RJ production by RJbs.
Project description:In this project, proteomic approaches were used to detect statistically significant changes in the honeybee proteome and to explore the mechanistic basis for the HG regulation that accompanies the seasonal changes.
Project description:The genome of the western honey bee (Apis mellifera) harbours ten different major royal jelly protein genes (mrjp1-10) which originate from a single-copy precursor via gene duplication. The evolutionary fate of duplicated genes is eventually determined over time as to result in loss due to pseudogenization, or in preservation due to neo- or sub-functionalization. Both fates were already observed in the mrjp gene cluster, as only mrjp1 - 9 are expressed, whereas mrjp10 was pseudogenized and represents an incomplete gene copy. In contrast, MRJP1 underwent neofunctionalization and developed an essential function within the food jelly of queen larvae, to guaranty the survival of the whole colony. We here show combining quantitative real time PCR with quantitative mass spectrometry that expression of most mrjps (mrjp1-5 and 7) shows an age dependent pattern in worker hypopharyngeal glands as well as in brains. Expression increases after hatching until the nurse bee period and is followed by a decrease in older workers that forage for different plant products. Mrjp6 expression deviates considerably from the expression profiles of the other mrjps and transcript abundance does not correlate with protein amount. Thus, either mrjp6 does fulfil a total different function or it might be on its way to pseudogenization. Furthermore, a tissue-specific function of the proteins MRJP8 and 9 in the hypopharyngeal glands and the brain can be excluded, suggesting a more general physiological than a nutritive function for both gene products.
Project description:Experiment was designed to study the effect of Deformed wing virus (DWV) and the mite Varroa destructor on global gene expression using microarray transcriptional profiling in developing worker honeybee (Apis mellifera). Newly hatched bee larvae (day 3 of bee development) were transferred from a Varroa-free colony with low DWV levels to a Varroa-infested colony with high levels of DWV in bees and Varroa mites. All transferred larvae were receiving the DWV strains present in this Varroa-infested colony with the food delivered by the nurse bees until their capping (day 8). About half of these larvae were capped with Varroa mite and were subjected to the mite piercing and feeding on their haemolymph during pupal development until sampling at purple eye stage (day 14). Exposure to the mite piercing and feeding resulted in about 1000-fold increase of the DWV levels in the majority of the mite-exposed pupae compared to the control pupae and the pupae not exposed to Varroa mites.
Project description:This experiment examines differences in gene expression between wildtype and an experimental strain (anarchistic) of worker honey bees (Apis mellifera). Mature wildtype and anarchistic workers tend to have non-active and active ovaries, respectively. Thus young workers from these strains are expected to show differential expression at loci involved in the regulation of worker reproduction, which occurs via arrhenotokous parthenogenesis.
Project description:This experiment examines differences in gene expression between wildtype and an experimental strain (anarchistic) of worker honey bees (Apis mellifera). Mature wildtype and anarchistic workers tend to have non-active and active ovaries, respectively. Thus young workers from these strains are expected to show differential expression at loci involved in the regulation of worker reproduction, which occurs via arrhenotokous parthenogenesis.
Project description:Transcriptome sequencing has become the main methodology for analyzing the relationship between genes and characteristics of interests, particularly those associated with diseases and economic traits. Because of its functional superiority, commercial royal jelly (RJ) and its production are major areas of focus in the field of apiculture. Multiple lines of evidence have demonstrated that many factors affect RJ output by activating or inhibiting various target genes and signaling pathways to augment their efficient replication. The coding sequences made available by the Honey Bee Genome Sequencing Consortium have permitted a pathway-based approach for investigating the development of the hypopharyngeal glands (HGs). In the present study, 3573941, 3562730, 3551541, 3524453, and 3615558 clean reads were obtained from the HGs of five full-sister honey bee samples using Solexa RNA sequencing technology. These reads were then assembled into 18378, 17785, 17065, 17105, and 17995 unigenes, respectively, and aligned to the DFCI Honey Bee Gene Index database. The differentially expressed genes (DEGs) data were also correlated with detailed morphological data for HGs acini. The results identify areas that warrant further study, including those that can be used to improve honey bee breeding techniques and help ensure stable yields of RJ with high quality traits. The 5 samples at given time (d3, d6, d9, d12, d16 after adult worker bees emergence from the comb) are in the critical stage of the RJ secretion and HGs developments indicated (triggered) the further caste differentiation (worker bees and queen) and task switch (nurse bees and foragers). 30 pooled heads of each samples were
Project description:Effect of genotype (wildtype vs. anarchist) on gene expression in developing (four-day-old) honeybee worker abdomens. Goal of experiment is to identify genes associated with ovary activation during worker development. These genes are hypothesised to be candidates for the regulation of worker sterility.