A microbial factory for defensive kahalalides in a tripartite marine symbiosis. Author Jindong Zan, Zhiyuan Li, Ma Tianero, Jeanette Davis, Russell Hill, Mohamed Donia Publication Year 2019 Type Journal Article Abstract Chemical defense against predators is widespread in natural ecosystems. Occasionally, taxonomically distant organisms share the same defense chemical. Here, we describe an unusual tripartite marine symbiosis, in which an intracellular bacterial symbiont (" Endobryopsis kahalalidefaciens") uses a diverse array of biosynthetic enzymes to convert simple substrates into a library of complex molecules (the kahalalides) for chemical defense of the host, the alga sp., against predation. The kahalalides are subsequently hijacked by a third partner, the herbivorous mollusk , and employed similarly for defense. " E. kahalalidefaciens" has lost many essential traits for free living and acts as a factory for kahalalide production. This interaction between a bacterium, an alga, and an animal highlights the importance of chemical defense in the evolution of complex symbioses. Keywords Animals, Biological Evolution, Glycosides, Symbiosis, Chlorophyta, Flavobacteriaceae, Gastropoda, Predatory Behavior, Triterpenes Journal Science Volume 364 Issue 6445 Date Published 2019 Jun 14 ISSN Number 1095-9203 DOI 10.1126/science.aaw6732 Alternate Journal Science PMID 31196985 PubMedGoogle ScholarBibTeXEndNote X3 XML