Microbial Richness of Marine Biofilms Revealed by Sequencing Full-Length 16S rRNA Genes

Abstract

Marine biofilms are a collective of microbes that can grow on many different surfaces immersed in marine environments. Estimating the microbial richness and specificity of a marine biofilm community is a challenging task due to the high complexity in comparison with seawater. Here, we compared the resolution of full-length 16S rRNA gene sequencing technique of a PacBio platform for microbe identification in marine biofilms with the results of partial 16S rRNA gene sequencing of traditional Illumina PE250 platform. At the same time, the microbial richness, diver-sity, and composition of adjacent seawater communities in the same batch of samples were ana-lyzed. Both techniques revealed higher species richness, as reflected by the Chao1 index, in the bio-films than that in the seawater communities. Moreover, compared with Illumina sequencing, PacBio sequencing detected more specific species for biofilms and less specific species for seawater. Mem-bers of Vibrio, Arcobacter, Photobacterium, Pseudoalteromonas, and Thalassomonas were significantly en-riched in the biofilms, which is consistent with the previous understanding of species adapted to a surface-associated lifestyle and validates the taxonomic analyses in the current study. To conclude, the full-length sequencing of 16S rRNA genes has probably a stronger ability to analyze more complex microbial communities, such as marine biofilms, the species richness of which has probably been under-estimated in previous studies.