Host and Environmental Specificity in Bacterial Communities Associated to Two Highly Invasive Marine Species (Genus Asparagopsis)

Abstract

As habitats change due to global and local pressures, population resilience, and adaptive processes depend not only on their gene pools but also on their associated bacteria communities. The hologenome can play a determinant role in adaptive evolution of higher organisms that rely on their bacterial associates for vital processes. In this study, we focus on the associated bacteria of the two most invasive seaweeds in southwest Iberia (coastal mainland) and nearby offshore Atlantic islands, Asparagopsis taxiformis and Asparagopsis armata. Bacterial communities were characterized using 16S rRNA barcoding through 454 next generation sequencing and exploratory shotgun metagenomics to provide functional insights and a backbone for future functional studies. The bacterial community composition was clearly different between the two species A. taxiformis and A. armata and between continental and island habitats. The latter was mainly due to higher abundances of Acidimicrobiales, Sphingomonadales, Xanthomonadales, Myxococcales, and Alteromonadales on the continent. Metabolic assignments for these groups contained a higher number of reads in functions related to oxidative stress and resistance to toxic compounds, more precisely heavy metals. These results are in agreement with their usual association with hydrocarbon degradation and heavy-metals detoxification. In contrast, A. taxiformis from islands contained more bacteria related to oligotrophic environments which might putatively play a role in mineralization of dissolved organic matter. The higher number of functional assignments found in the metagenomes of A. taxiformis collected from Cape Verde Islands suggest a higher contribution of bacteria to compensate nutrient limitation in oligotrophic environments. Our results show that Asparagopsis-associated bacterial communities have host-specificity and are modulated by environmental conditions. Whether this environmental effect reflects the host's selective requirements or the locally available bacteria remains to be addressed. However, the known functional capacities of these bacterial communities indicate their potential for eco-physiological functions that could be valuable for the host fitness.

High temporal variability in airborne bacterial diversity and abundance inside single‐family residences

“…Statistical analyses were conducted in R, unless otherwise indicated. In accordance with some previous studies (e.g.,) rarefied OTU tables were square‐root‐transformed, and Bray–Curtis dissimilarity matrices were generated for sample comparisons. We used permutational MANOVA (PERMANOVA) as implemented in PRIMER v6 to test for significant differences in bacterial community composition between groups of samples (e.g., within vs. between homes, in indoor vs. outdoor air, and for categorical home characteristics).…”

Climate Change Impacts on Seagrass Meadows and Macroalgal Forests: An Integrative Perspective on Acclimation and Adaptation Potential

“…However, bacterial communities associated to marine macrophytes are not fixed and can change temporally and spatially across seasons, lifespan, life stages and tissue types by biotic and abiotic factors (Staufenberger et al, 2008;Aires et al, 2016;Mancuso et al, 2016). While bacterial communities of some macroalgae appear species-or even lineage-specific Vieira et al, 2016), this is yet unclear for kelps and seagrasses due to the low number of studies with inter-species comparisons.…”

“…Marine macrophytes associate with bacterial communities that differ strongly from those of their surrounding seawater, sediment or substrate Aires et al, 2016;Cúcio et al, 2016). However, bacterial communities associated to marine macrophytes are not fixed and can change temporally and spatially across seasons, lifespan, life stages and tissue types by biotic and abiotic factors (Staufenberger et al, 2008;Aires et al, 2016;Mancuso et al, 2016).…”

Identification of Asparagopsis armata‐associated bacteria and characterization of their bioactive potential

“…The second most frequent family observed in our study Staphylococcaceae (23.8%) was not detected in the study of Aires and coworkers, in which the most frequent bacteria belong to the Saprospiraceae family (between 36% and 47% depending on the location) that was not detected by us. Despite the different methods used, the differences observed reinforce the role of geographical localization and environmental conditions in the bacteria community diversity associated to algae (Aires et al., ).…”

“…In fact, Vibrio species are widely common in aquatic environments, especially in coastal waters, which may justify their high occurrence in aquatic samples. However, different results were obtained in a study of the bacterial communities associated with A. armata in three locations in the southwest coast of Portugal, using a metagenomic approach (Aires, Serrão, & Engelen, ) in which considering the samples identified to the family level less than 1% belongs to the Vibrionaceae family. The second most frequent family observed in our study Staphylococcaceae (23.8%) was not detected in the study of Aires and coworkers, in which the most frequent bacteria belong to the Saprospiraceae family (between 36% and 47% depending on the location) that was not detected by us.…”