Transcriptomic analysis of the red seaweed Laurencia dendroidea (Florideophyceae, Rhodophyta) and its microbiome

Abstract

BackgroundSeaweeds of the Laurencia genus have a broad geographic distribution and are largely recognized as important sources of secondary metabolites, mainly halogenated compounds exhibiting diverse potential pharmacological activities and relevant ecological role as anti-epibiosis. Host-microbe interaction is a driving force for co-evolution in the marine environment, but molecular studies of seaweed-associated microbial communities are still rare. Despite the large amount of research describing the chemical compositions of Laurencia species, the genetic knowledge regarding this genus is currently restricted to taxonomic markers and general genome features. In this work we analyze the transcriptomic profile of L. dendroidea J. Agardh, unveil the genes involved on the biosynthesis of terpenoid compounds in this seaweed and explore the interactions between this host and its associated microbiome.ResultsA total of 6 transcriptomes were obtained from specimens of L. dendroidea sampled in three different coastal locations of the Rio de Janeiro state. Functional annotations revealed predominantly basic cellular metabolic pathways. Bacteria was the dominant active group in the microbiome of L. dendroidea, standing out nitrogen fixing Cyanobacteria and aerobic heterotrophic Proteobacteria. The analysis of the relative contribution of each domain highlighted bacterial features related to glycolysis, lipid and polysaccharide breakdown, and also recognition of seaweed surface and establishment of biofilm. Eukaryotic transcripts, on the other hand, were associated with photosynthesis, synthesis of carbohydrate reserves, and defense mechanisms, including the biosynthesis of terpenoids through the mevalonate-independent pathway.ConclusionsThis work describes the first transcriptomic profile of the red seaweed L. dendroidea, increasing the knowledge about ESTs from the Florideophyceae algal class. Our data suggest an important role for L. dendroidea in the primary production of the holobiont and the role of Bacteria as consumers of organic matter and possibly also as nitrogen source. Furthermore, this seaweed expressed sequences related to terpene biosynthesis, including the complete mevalonate-independent pathway, which offers new possibilities for biotechnological applications using secondary metabolites from L. dendroidea.

The Laurencia Paradox: An Endless Source of Chemodiversity

“…Despite the high number of research studies describing the chemical composition of Laurencia species, the genetic knowledge regarding this genus is currently restricted to taxonomic markers and general genome features. In recent work, de Oliveira and co-workers analyzed the transcriptomic profile of Laurencia dendroidea, aiming to unveil the genes involved in the biosynthesis of terpenoid compounds in this seaweed and the interactions between this host and its associated microbiome, and showed bacteria to be the dominant active group in its microbiome [53].…”

Herbivore-induced defence response in the brown seaweedFucus vesiculosus(Phaeophyceae): temporal pattern and gene expression

“…Several genomic studies have provided insight into internal regulative processes in seaweeds, but these investigations were mainly focused on genes involved in carbohydrate synthesis (e.g. Zhou & Ragan, 1995), resistance to toxic metals (Owen et al, 2012) or epiphytes (Weinberger et al, 2011a) and acclimation to abiotic stresses (Dittami et al, 2009;Pearson et al, 2010;Heinrich et al, 2012b) (but see Cosse et al, 2009;de Oliveira et al, 2012). In contrast, cellular processes underlying the induction of anti-herbivory defences have been studied in detail for vascular plants.…”

Progress in the Chemistry of Organic Natural Products 102

“…Mild treatment of the ingenol 20-esters [71] can, however, lead to the generation of 5-esters, at least with saturated acyl groups [53]. 3.1.6), and represent therefore essentially extraction and/or fractionation artefacts.…”

“…In recent work, de Oliveira and co-workers analyzed the transcriptomic profile of Laurencia dendroidea, aiming to unveil the genes involved in the biosynthesis of terpenoid compounds in this seaweed and the interactions between this host and its associated microbiome, and showed bacteria to be the dominant active group in its microbiome [53]. Nonetheless, molecular studies of seaweed-associated microbial communities are still rare.…”