Category Archives: Bees

PeerJ pre-print on sacbrood virus

We have recently submitted a paper to PeerJ on gene expression changes resulting from deformed wing virus and sacbrood virus infection. A pre-print of this manuscript can be viewed on the PeerJ website.

Manuscript authors and title

Ryabov EV, Fannon JM, Moore JD, Wood GR, Evans DJ. (2015Evolutionarily related Sacbrood virus and Deformed wing virus evoke different transcriptional responses in the honeybee which may facilitate horizontal or vertical transmission of these virusesPeerJ PrePrints 3:e1749

Abstract

Sacbrood virus (SBV) and deformed wing virus (DWV) are evolutionarily related positive-strand RNA viruses, members of the Iflavirus group, which infect the honeybee Apis mellifera, but have strikingly different levels of virulence when transmitted orally. Honeybee larvae orally infected with SBV usually accumulate high levels of the virus, which halts larval development and causes insect death. In contrast, oral DWV infection at the larval stage usually causes asymptomatic infection with low levels of the virus, although high doses of ingested DWV could lead to DWV replicating to high levels. We investigated effects of DWV and SBV infection on the transcriptome of honeybee larvae and pupae using global RNA-Seq and real-time PCR analysis. This showed that high levels of SBV replication resulted in down-regulation of the genes involved in cuticle and muscle development, together with changes in expression of putative immune-related genes. In particular, honeybee larvae with high levels of SBV replication, with and without high levels of DWV replication, showed concerted up-regulated expression of antimicrobial peptides (AMPs), and down-regulated expression of the prophenoloxidase activating enzyme (PPAE) together with up-regulation of the expression of a putative serpin, which could lead to the suppression of the melanisation pathway. The effects of high SBV levels on expression of these immune genes were unlikely to be a consequence of SBV-induced developmental changes, because similar effects were observed in the honeybee pupae infected by injection. We suggest that the effects of SBV infection on the honeybee immunity could be an adaptation to horizontal transmission of the virus. Up-regulation of the expression of AMP genes in the SBV-infected brood may contribute to protection of the SBV virus particles in dead larvae from bacterial degradation. Suppression of the melanisation may also reduce the loss of infectivity of SBV in the larvae. Therefore it is possible that activation of AMP expression and suppression of melanisation could increase ability of SBV to be transmitted horizontally via cannibalization route. We observed no changes of AMPs and the melanisation pathway genes expression in the orally infected larvae with high levels of DWV replication alone. In the injected pupae, high levels of DWV alone did not alter expression of the tested melanisation pathway genes, but resulted in up-regulation of the AMPs, which could be contributed to the effect of DWV on the regulation of AMP expression in response to wounding. We suggest that the effects of single DWV infection on the expression of these immune-related genes could reflect evolutionary adaptations of DWV to vertical transmission. Up-regulation of AMPs is costly and suppression of melanisation may increase susceptibility to infections, therefore these changes may have negative impact on honeybee survival and, consequently, of the survival of DWV.

Somerset BKA lecture day

DWV symptoms

DWV symptoms

I’m delighted to be sharing the programme with Michael Palmer and Celia Davies at the Somerset BKA lecture day this Saturday (21st February ’15). I’ll be adding a small bit of science to the day and no doubt benefiting significantly from their wealth of beekeeping expertise. It should be a very enjoyable event.

Update – it was a very enjoyable event.  Aside from a few audio problems with a misbehaving microphone a packed hall enjoyed two talks by Celia Davies on Summer and Winter Bees and A World of Scents and a further two from Michael Palmer on the Sustainable Apiary and Queen rearing. If you’ve not heard Michael talk about the importance of overwintering nucs for sustainable beekeeping then you should either try and catch him on his current UK tour or watch him deliver the talk at the National Honey Show on YouTube. I think I’ve heard the talk three times now and have learnt something new every time. All the talks – including our contribution on the science of Varroa and deformed wing virus – generated lots of questions and discussions. With thanks to Sharon Blake for the invitation and organisation of the day.

Honey gifts

The University of Warwick is 50 years old in 2015. As part of the 50th anniversary celebrations attendees at the launch event were given “goody bags” containing, amongst other things, a small jar of honey from hives kept on campus or in the neighbouring farmland. Each carried a small tag advertising the honeybee research conducted in our lab …

CABK Stratford Conference

Falcon Hotel Stratford

Falcon Hotel Stratford

I’m delighted to be speaking at the  CABK Stratford Conference (the Central Association of BeekeepersBringing Science to the Beekeeper) on Saturday and Sunday 22/23 November 2014. I’ll be discussing the identification of a virulent strain of deformed wing virus, characteristics of its transmission and potential ways it might be controlled in the future. The CABK website doesn’t yet appear to list other speakers, but the provisional programme I’ve seen lists Alison Haughton from Rothamsted, Ben Jones from FERA, Jochen Plugfelder from Bern and Bob Smith from Kent.

There should be ample time for discussions so please introduce yourself if you want to chat.

New BBSRC grant

We’re delighted to have been awarded a new BBSRC grant for studies of “The biology and pathogenesis of Deformed Wing Virus, the major virus pathogen of honeybees“. These studies will help us understand the enhanced virulence of particular strains of DWV and to determine how effective antiviral therapies may be developed.

Hives and himalayan balsam

Hives and himalayan balsam