Molecular Mechanism of the Two-Component Suicidal Weapon of Neocapritermes taracua Old Workers

0459003 - ÚOCHB 2017 RIV US eng J - Journal Article
Bourguignon, T. - Šobotník, J. - Brabcová, Jana - Sillam-Dusses, D. - Buček, Aleš - Krasulová, Jana - Vytisková, B. - Demianova, Z. - Mareš, Michael - Roisin, Y. - Vogel, H.
Molecular Mechanism of the Two-Component Suicidal Weapon of Neocapritermes taracua Old Workers.
Molecular Biology and Evolution. Roč. 33, č. 3 (2016), s. 809-819. ISSN 0737-4038. E-ISSN 1537-1719
R&D Projects: GA MŠMT LO1302
Institutional support: RVO:61388963
Keywords : altruism * colony defense * termite * Isoptera * laccase
Subject RIV: CE - Biochemistry
Impact factor: 6.202, year: 2016

In termites, as in many social insects, some individuals specialize in colony defense, developing diverse weaponry. As workers of the termite Neocapritermes taracua (Termitidae: Termitinae) age, their efficiency to perform general tasks decreases, while they accumulate defensive secretions and increase their readiness to fight. This defensive mechanism involves self-sacrifice through body rupture during which an enzyme, stored as blue crystals in dorsal pouches, converts precursors produced by the labial glands into highly toxic compounds. Here, we identify both components of this activated defense system and describe the molecular basis responsible for the toxicity of N. taracua worker autothysis. The blue crystals are formed almost exclusively by a specific protein named BP76. By matching N. taracua transcriptome databases with amino acid sequences, we identified BP76 to be a laccase. Following autothysis, the series of hydroquinone precursors produced by labial glands get mixed with BP76, resulting in the conversion of relatively harmless hydroquinones into toxic benzoquinone analogues. Neocapritermes taracua workers therefore rely on a two-component activated defense system, consisting of two separately stored secretions that can react only after suicidal body rupture, which produces a sticky and toxic cocktail harmful to opponents.
Permanent Link: http://hdl.handle.net/11104/0259200