Ecology and molecular regulation of defensive symbiosis in Lagriinae beetles

Darkling beetles of the subfamily Lagriinae are polyphagous insects with a wide distribution in the tropics and temperate regions. Early morphological descriptions highlighted the presence of specialized organs associated to the reproductive system of females as well as in the dorsal region of larvae, which were believed to harbor symbiotic microorganisms. We identified these bacteria as Burkholderia gladioli (β-Proteobacteria) and confirmed their vertical transmission route from the female reproductive tract via the egg surface into the larval organs. Manipulative experiments suggest a protective role of the bacteria on the egg surface, highlighting the potential of symbiotic microbes to protect immature life stages of their hosts against antagonists. We are currently investigating the chemical and genetic basis of the symbionts’ protective activity as well as the role of the host plant for horizontal transmission of the bacteria.

Laura Flórez, Martin Kaltenpoth, Rebekka Janke, Ramya Ganesan

The pictures show different life stages of Lagria villosa beetles (by Rebekka Janke), and Fluorescence in situ hybridization of Burkholderia bacterial symbionts in female L. villosa accessory glands (by Paul Gaube / Laura Flórez).

Selected publications:

Flórez, L. V., Scherlach K., Miller, I. J., Rodrigues, A., Kwan, J. C., Hertweck, C., Kaltenpoth, M. (2018). An antifungal polyketide associated to horizontally acquired genes supports symbiont-mediated defense in Lagria villosa beetles. Nature Communications. 9, 2478.

Dose, B., Niehs, S. P., Scherlach, K., Flórez, L. V., Kaltenpoth, M., & Hertweck, C. (2018). Unexpected Bacterial Origin of the Antibiotic Icosalide: Two-Tailed Depsipeptide Assembly in Multifarious Burkholderia Symbionts. ACS Chemical Biology. 13(9), 2414–2420.

Gaube, P., Kaltenpoth, M. and Flórez, L. V. (2017). Infection of soybean plants with the insect bacterial symbiont Burkholderia gladioli and evaluation of plant fitness. Bio-protocol 7(24): e2663.

Flórez, L. V. and Kaltenpoth, M. (2017). Symbiont dynamics and strain diversity in the defensive mutualism between Lagria beetles and Burkholderia. Environ Microbiol. 19, 3674-3688.

Flórez, L. V., Scherlach, K., Gaube, P., Ross, C., Sitte, E., Hermes, C., Rodrigues, A., Hertweck, C. & Kaltenpoth, M. (2017). Antibiotic-producing symbionts dynamically transition between plant pathogenicity and insect defensive mutualism. Nature Communications, 8: 15172.