A novel Amazonian reef biome was discovered, encompassing large rhodolith and sponge beds under low light, low oxygen, and high POC.

Herein we report the isolation and spectroscopic identification of fistularin-3 (1), 11-hydroxyaerothionin (2), and verongidoic acid (3), as well as the UPLC-HRMS detection of aerothionin (4), homopurpuroceratic acid B (5), purealidin L (6), and aplysinamisine II (7), from cultures of the marine bacterium Pseudovibrio denitrificans Ab134, isolated from tissues of the marine sponge Arenosclera brasiliensis. These results unambiguously demonstrate for the first time that bromotyrosine-derived alkaloids that were previously isolated only from Verongida sponges can be biosynthesized by a marine bacterium.

Marine sponge holobionts harbor complex microbial communities whose members may be the true producers of secondary metabolites accumulated by sponges. Bromopyrrole alkaloids constitute a typical class of secondary metabolites isolated from sponges that very often display biological activities. Bromine incorporation into secondary metabolites can be catalyzed by either halogenases or haloperoxidases. The diversity of the metagenomes of sponge holobiont species containing bromopyrrole alkaloids (Agelas spp. and Tedania brasiliensis) as well as holobionts devoid of bromopyrrole alkaloids spanning in a vast biogeographic region (approx. Seven thousand km) was studied. The origin and specificity of the detected halogenases was also investigated. The holobionts Agelas spp. and T. brasiliensis did not share microbial halogenases, suggesting a species-specific pattern. Bacteria of diverse phylogenetic origins encoding halogenase genes were found to be more abundant in bromopyrrole-containing sponges. The sponge holobionts (e.g., Agelas spp.) with the greatest number of sequences related to clustered, interspaced, short, palindromic repeats (CRISPRs) exhibited the fewest phage halogenases, suggesting a possible mechanism of protection from phage infection by the sponge host. This study highlights the potential of phages to transport halogenases horizontally across host sponges, particularly in more permissive holobiont hosts, such as Tedania spp.

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