The Secondary Metabolism Potential Of Sponge Microbiome And Effects Of Warming And Acidification On The Microbiota

Sponges are well known to be hosts for a complex microbiota community.They are not only among the richest known sources of marine natural products,but also important members of coral reefs.Through shotgun metagenomic sequencing and analysis,we studied the secondary metabolic potential of the microbiota of sponge Theonella swinhoei from the South China Sea.We found that the abundant bacterial phyla in T.swinhoei metagenome were Proteobacteria(30.5%),Actinobacteria(6.2%),Poribacteria(3.6%),Firmicutes(3.5%),Chloroflexi(2.6%)and Cyanobacteria(2.1%).The abundances of Candidatus Entotheonella sp.TSY1 and Candidatus Entotheonella sp.TSY2 in T.swinhoei were higher than those in other habitats.The metagenomic read fractions of polyketide synthase modules and related proteins(COG3321)and non-ribosomal peptide synthetase modules and related proteins(COG1020)in this sponge microbiota were higher than those from other sponges.Besides Candidatus Entotheonella,secondary metabolite biosynthesis gene clusters of the sponge microbiota were associated with unknown bacteria and putative cyanobacteria.The results showed that the microbiota in sponge T.swinhoei from the South China Sea had great secondary metabolic potential,and provided evidence for microbial origin of sponge-derived compounds,which laid a basis for further utilization of T.swinhoei symbiotic microbes in the production of marine natural products.The effect of global climate change on ocean ecosystems and sessile,reef-building animals,such as sponges and corals,is of increasing concern.But fewer studies about the effect of environmental stressors on sponge microbiota have been reported.We used the sponge Spheciospongia sp.widely distributed in South China Sea as a model to explore the sponge microbiota community changes in response to ocean acidification and elevated seawater temperature,as well as its recovery potential after removing the stressors.The results showed that seawater warming alone,as well as combined seawater warming and acidification had significant effects on the community structure of sponge microbiota,particulatly seawater warming alone had the most influence.Ocean acidification alone had no significant effects on the microbial community structure.After removing the acidification and temperature stresses,microbial community of sponge treated by elevated seawater temperature alone or combined elevated seawater temperature and ocean acidification could not be recovered to the level of control.