Abstract
Gut microbiota have important roles in the survival and adaptation of the host. Ophiuroids, as the worldwide dominant benthos, have ecological roles in benthic–pelagic coupling in the sea floor. However, little is known about the composition and diversity of their gut microbiota and its potential functions in benthic ecosystems. In present study, we preformed 16S rRNA sequencing and function analysis in four dominant species (Stegophiura sladeni, Ophiopholis mirabilis, Ophiura sarsii vadicola, and Ophiura kinbergi) with two feeding types (suspension feeding/herbivores and scavenger/carnivores) from the Yellow Sea, China. Results showed that 56 phyla and 569 genera of microbiota were identified among ophiuroid guts. Multivariate and diversity analyses showed that the ophiuroid gut microbiota were independent and have higher biodiversity to the sediment microbial in the Yellow Sea. Phyla Proteobacteria, Firmicutes, Tenericutes, and Bacteroidetes were the dominant bacteria, with more than 80% abundance among the four ophiuroid species. A comparison among the gut microbial compositions among four ophiuroids showed the similarity of two offshore carnivore ophiuroids (S. sladeni and O. sarsii vadicola) and variation in the dominant microbiota types of three nearshore ophiuroids (S. sladeni, O. mirabilis, and O. kinbergi). The functional analysis revealed the significant differences of the environment-related expression in S. sladeni gut microbiota between nearshore and offshore environments. The Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) functional annotation showed the significant divergence of metabolism pathways between two nearshore species, the herbivores O. mirabilis and carnivores S. sladeni, such as the Lipid metabolism, Carbohydrate metabolism, and Metabolism of cofactors and vitamins. The homolog search and phylogenetic analysis identified the first gut symbiotic Candidatus Hepatoplasma in S. sladeni with important roles for the nutrient metabolisms. Overall, our study reported the comprehensive data of ophiuroid gut microbiota, while the functional microbiome provides insight into the physiology and environmental adaptation in ophiuroids.
Highlights
Ophiuroidea, with 2,064 known species from 16 families, are the largest class of Echinodermata (Geraldi et al, 2017)
We focus on the gut microbiota communities of ophiuroids that lived in the Yellow Sea, a marginal sea between China and Korean Peninsula with hydrological phenomena and high biodiversity (Li, 2011)
We report the gut microbiota of four dominant ophiuroids in the Yellow Sea, and we enhance our understanding of diversity and association of host–microbiomes in the environmental adaptation of echinoderms
Summary
Ophiuroidea (brittle stars), with 2,064 known species from 16 families, are the largest class of Echinodermata (Geraldi et al, 2017). They play an important ecological role in food webs (Wu and Shin, 1997; Harris et al, 2009; Enoksen and Reiss, 2017) and nutrient recycling in the marine benthic ecosystems (Lebrato et al, 2010; Ravelo et al, 2015). Brittle stars from families Gorgonocephalidae and Amphiuridae are primarily suspension feeding on organic detritus, plankton, and bacteria (Iken et al, 2001). Scavenger ophiuroids, including Ophiopyrgidae and Ophiacanthidae, feed on dead organisms and small animals (usually dead), including crustaceans, mollusks, and worms (Adarsha et al, 2018). The assemblage of ophiuroid populations is a common phenomenon in different habitats (Murat et al, 2016), given that they could enhance the process of benthic–pelagic coupling in the sea floor (Geraldi et al, 2017)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
