Biochemical basis of endogenous bioluminescent springtail Lobella sauteri (Collembola).

Bioluminescence plays important roles among animals in both intra- and inter-species communication. A variety of bioluminescent organisms inhabit soil environments, even in areas where light penetration is minimal. However, due to the lack of a model system to study underground bioluminescence, the biology and molecular mechanisms underlying this phenomenon remain largely unknown. Springtails (Collembola) are representative soil animals, and we recently identified Lobella sauteri (Neanuridae) as a bioluminescent species. L. sauteri can be maintained over multiple generations under laboratory conditions on a single food source, the plasmodium Fuligo septica, with a generation time of approximately 3 months. Bioluminescence was observed in all developmental stages of L. sauteri in laboratory-raised populations. The light emission exhibited periodic changes and increased before ecdysis, coinciding with the whitening of its tubercles. The bioluminescent reaction in vitro requires a small molecular (luciferin) fraction, an enzyme (luciferase) fraction, adenosine triphosphate (ATP), and Mg2+. Comparative transcriptomic and biochemical analyses suggest that L. sauteri employs a novel endogenous bioluminescent molecular mechanism. We propose that L. sauteri provides a valuable research opportunity for investigating novel bioluminescence systems and underground light-based communication.