Establishment and transcriptomic characterization of cell lines and sublines from the small hive beetle, Aethina tumida (Coleoptera: Nitidulidae)

Authors: Goodman, Cynthia; Corcoran, Jacob; Saathoff, Stephen - Steve; Ringbauer, Joseph - Joe; GUO, YA - University Of Florida; Stamps, Marilise; BONNING, BRYONY - University Of Florida; Stanley, David

Submitted to: Society for In Vitro Biology Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 4/1/2021
Publication Date: 5/6/2021
Citation: Goodman, C.L., Corcoran, J., Saathoff, S.G., Ringbauer Jr, J.A., Guo, Y., Stamps, M.M., Bonning, B., Stanley, D.W. 2021. Establishment and transcriptomic characterization of cell lines and sublines from the small hive beetle, Aethina tumida (Coleoptera: Nitidulidae). Society for In Vitro Biology Proceedings. 57:41–47. https://doi.org/10.1007/s11626-021-00566-6.
DOI: https://doi.org/10.1007/s11626-021-00566-6

Interpretive Summary: Small hive beetle (SHB) adults deposit their eggs in honey bee colonies and the larvae feed on honey, pollen and honey bee larvae. These beetles have become one of the serious challenges to the health and sustainability of honey bee colonies, which contribute over $20 billion per year in pollination services to high-value crops, such as almonds, apples, melons and broccoli. Industrial and academic research to control SHB damage is aimed at developing novel SHB-specific insecticides. The research process involves directly testing hundreds of thousands of known and novel chemicals for their ability to kill SHBs while not harming honey bees or other beneficial insects, such as predatory insects used in biological control of pest insects. The classical testing methods involves exposing a pest insect, such as SHBs, to a chemical and recording the resulting death rates. This was a very expensive process that required rearing and maintaining large populations of target pest insects. Modern testing methods rely on establishing insect cell lines and testing the effects of potential insecticides on the cells. We are working to establish SHB cell lines as tools for rapidly and less costly testing the influence of many chemicals on the cell lines. So far, we have established two continuously replicating SHB cell lines, one from SHB eggs and a second line from a combination of eggs and new larvae. We also created 20 permanent sub-cultures, which we preserved in a deep-frozen system, from which they can be revived. These SHB cell lines are now available to researchers on request.

Technical Abstract: The small hive beetle (SHB), Aethina tumida, originated in sub-Saharan Africa and now has a world-wide distribution. Adult SHBs deposit their eggs in honey bee colonies and the larvae feed on honey, pollen and honey bee larvae. Over time this negatively impacts honey bee populations, which translates into a major economic impact on agriculture. A number of measures have been implemented to control SHBs, including the use of biological agents. Current efforts focus on developing novel, SHB-specific insecticides, which could be enhanced with tools to screen candidate compounds against cell lines derived from SHB tissues. Here we report on two continuously replicating SHB cell lines: BCIRL-AtuE-1127-SGS from eggs and BCIRL-AtuNE-1129-SGS from eggs and neonate larvae. Each line consists of a variety of cell morphotypes, including firmly attached asymmetrical cells and loosely-attached spherical cells. Numerous sublines were produced by limiting dilution to isolate different cell morphotypes; 20 sublines were selected and cryopreserved. Of these, 3 were selected from the AtuNE-1129 parental line and 6 from the AtuE-1127 line for further molecular and genetic characterization. DNA barcoding confirmed that the sublines were derived from SHB tissues. Growth curves indicated their doubling times ranged from 29.2 h to 68.4 h. Gene expression profiles were evaluated in three sublines via RNA-Seq. The transcriptomic libraries and gene expression profiles will aid in the identification of potential insecticidal targets present in the cell lines. Here we present a small subset of genes expressed in these cell lines that could support insecticide development programs, including: various members of ABC transporter families A-G; calcium transporters, such as plasma membrane and endoplasmic reticulum calcium ATPases; and GPCRs with neurophysiological functions, such as octopamine and pyrokinin receptors.