Keeping it in the family: Coevolution of latrunculid sponges and their dominant bacterial symbionts

Abstract

The Latrunculiidae are a family of cold water sponges known for their production of bioactive pyrroloiminoquinone alkaloids. Previously it was shown that the bacterial community associated with a Tsitsikamma sponge species comprises unusual bacterial taxa and is dominated by a novel Betaproteobacterium. Here, we have characterized the bacterial communities associated with six latrunculid species representing three genera (Tsitsikamma, Cyclacanthia, and Latrunculia) as well as a Mycale species, collected from Algoa Bay on the South African southeast coast. The bacterial communities of all seven sponge species were dominated by a single Betaproteobacterium operational taxonomic unit (OTU 0.03), while a second OTU 0.03 was dominant in the Mycale sp. The Betaproteobacteria OTUs from the different latrunculid sponges are closely related and their phylogenetic relationship follows that of their hosts. We propose that the latrunculid Betaproteobacteria OTUs are members of a specialized group of sponge symbionts that may have coevolved with their hosts. A single dominant Spirochaetae OTU 0.03 was present in the Tsitsikamma and Cyclacanthia sponge species, but absent from the Latrunculia and Mycale sponges. This study sheds new light on the interactions between latrunculid sponges and their bacterial communities and may point to the potential involvement of dominant symbionts in the biosynthesis of the bioactive secondary metabolites.

Characterization of the Gut Microbiota of the Antarctic Heart Urchin (Spatangoida) Abatus agassizii

“…The gut tissue of A. agassizii was dominated by Spirochaetia, mostly represented by the genus Spirochaeta which was prevalent in all of the samples and accounted for as much as 80% relative abundance of the class. Spirochaetes are motile freeliving, facultative/obligate anaerobes (Leschine et al, 2006), associated with numerous marine invertebrates, among others, corals (Lawler et al, 2016;Van De Water et al, 2016), sponges (Matcher et al, 2017;Kellogg, 2019), sea stars (Jackson et al, 2018), and at the body surface of the regular sea urchin species Tripneustes gratilla (<15% relative abundance) (Brink et al, 2019). Such a prevalence inside the gut of a sea urchin has never been described and suggests a specific interaction between Spirochaeta and the Abatus host.…”

A Place to Call Home: An Analysis of the Bacterial Communities in Two Tethya rubra Samaai and Gibbons 2005 Populations in Algoa Bay, South Africa

“…In a previous study we found no evidence of seasonal variation in the bacterial communities associated with Tsitsikamma favus sponges collected from Evans Peak [27]. Furthermore, a statistical analysis of the bacterial communities from four seawater samples collected at Evans Peak between August 2014 and June 2016 showed that there was no significant difference ( p = 0.71) between them (S.H.…”

The colourful chemistry of South African latrunculid sponges

“…In an effort to unequivocally establish the biosynthetic origin of the tsitsikammamines, a detailed community structure analysis of the symbiotic bacteria found in T. favus sponges collected from Algoa Bay is currently underway at Rhodes University. 9,33 The microbial community analyses are coupled to a metagenomic search for microbial biosynthetic gene clusters that might ultimately be responsible for the biosynthesis of the tsitsikammamines. The structural novelty and bioactivity of the tsitsikammamines has attracted interest from synthetic chemists and tsitsikammamine A was first synthesised by Delfourne and co-workers.…”