|CHAIMANEE, VEERANAN - Maejo University|
|CHANTAWANNAKUL, PANUWAN - Chiang Mai University|
|Chen, Yanping - Judy|
Submitted to: Apidologie
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/26/2013
Publication Date: 7/1/2014
Citation: Chaimanee, V., Chantawannakul, P., Chen, Y., Evans, J.D., Pettis, J.S. 2014. Effects of host age on susceptibility to infection and immune-gene expression in honey bee queens (Apis mellifera) inoculated with Nosema ceranae. Apidologie. 45(4): 451-463.
Interpretive Summary: Nosema ceranae is a gut parasite that can infect all members of a honey bee colony. In this study newly emerged adult queen honey bees of varying ages (1 day, 6 day and 12 day old) were infected with N. ceranae. Younger queens were found to be more likely to become infected than the older queens. This study also looks at the effects of N. ceranae on immune-gene expression queens of different ages and shows that antimicrobial peptide genes (apidaecin, eater and vitellognin) expression is different among queens of different ages. This clearly shows that immune response to N. ceranae change as a queen ages and this may lead to a better understanding of honey bee queens’ abilities to resist infection of this gut parasite. This information is useful for beekeepers who rear queens and may help maintain healthy queens in honey bee colonies.
Technical Abstract: Nosema ceranae is a microsporidium parasite infecting honey bees worldwide. All colony members including workers, drones and queens can become infected. In this study, we inoculated queens of age 1, 6 and 12 days post adult emergence, with N. ceranae spores of different doses and allowed them to age an additional 12 days. The results indicated that younger queens were indeed more susceptible to N. ceranae inoculation than older queens. Moreover, this is the first report of the effects of N. ceranae inoculation on immune-gene expression in queens of different ages. Our results demonstrated that the expression of the antimicrobial peptide genes apidaecin, eater, and vitellogenin in the gut and the remaining abdomen were different among queens of different ages when inoculated with N. ceranae. All three ages of queens inoculated by N. ceranae showed up-regulation of apidaecin in gut tissue 6 days after inoculation, but only in queens aged 1 day post-emergence were the differences significant. However, transcript levels of eater were increased in all three ages of queens when sampled on day 12, and significant differences were obtained in queens inoculated at 6 and 12 days post emergence. We clearly show that immune responses to N. ceranae changes as queen age and this knowledge may provide clues for understanding the ability of queens to resist infection by this gut parasite.