Diterpenes are major defensive small molecules that enable soft corals to survive without a tough exterior skeleton, and, until now, their biosynthetic origin has remained intractable. Furthermore, biomedical application of these molecules has been hampered by lack of supply. Here, we identify and characterize coral-encoded terpene cyclase genes that produce the eunicellane precursor of eleutherobin and cembrene, representative precursors for the >2,500 terpenes found in octocorals. Related genes are found in all sequenced octocorals and form their own clade, indicating a potential ancient origin concomitant with the split between the hard and soft corals. Eleutherobin biosynthetic genes are colocalized in a single chromosomal region. This demonstrates that, like plants and microbes, animals also harbor defensive biosynthetic gene clusters, supporting a recombinational model to explain why specialized or defensive metabolites are adjacently encoded in the genome.

二萜是主要的防御性小分子，使软珊瑚能够在没有坚硬的外部骨骼的情况下生存，并且直到现在，它们的生物合成起源仍然难以解决。此外，这些分子的生物医学应用因供应不足而受到阻碍。在这里，我们鉴定并描述了珊瑚编码的萜烯环化酶基因，这些基因产生了五加酚和松柏烯的链霉烷前体，这是在八珊瑚中发现的 > 2,500 种萜烯的代表性前体。在所有已测序的八珊瑚中都发现了相关基因，并形成了它们自己的进化枝，这表明伴随硬珊瑚和软珊瑚分裂的潜在古代起源。刺五加素生物合成基因共定位于单个染色体区域。这表明，与植物和微生物一样，动物也具有防御性生物合成基因簇，