Table_1_Shotgun Metagenomics Reveals the Benthic Microbial Community Response to Plastic and Bioplastic in a Coastal Marine Environment.DOCX

Plastic is incredibly abundant in marine environments but little is known about its effects on benthic microbiota and biogeochemical cycling. This study reports the shotgun metagenomic sequencing of biofilms fouling plastic and bioplastic microcosms staged at the sediment–water interface of a coastal lagoon. Community composition analysis revealed that plastic biofilms were indistinguishable in comparison to a ceramic biofilm control. By contrast, bioplastic biofilms were distinct and dominated by sulfate-reducing microorganisms (SRM). Analysis of bioplastic gene pools revealed the enrichment of esterases, depolymerases, adenylyl sulfate reductases (aprBA), and dissimilatory sulfite reductases (dsrAB). The nearly 20-fold enrichment of a phylogenetically diverse polyhydroxybutyrate (PHB) depolymerase suggests this gene was distributed across a mixed microbial assemblage. The metagenomic reconstruction of genomes identified novel species of Desulfovibrio, Desulfobacteraceae, and Desulfobulbaceae among the abundant SRM, and these genomes contained genes integral to both bioplastic degradation and sulfate reduction. Findings indicate that bioplastic promoted a rapid and significant shift in benthic microbial diversity and gene pools, selecting for microbes that participate in bioplastic degradation and sulfate reduction. If plastic pollution is traded for bioplastic pollution and sedimentary inputs are large, the microbial response could unintentionally affect benthic biogeochemical activities through the stimulation of sulfate reducers.

塑料在海洋环境中丰度极高，但目前人们对其对底栖微生物群（benthic microbiota）与生物地球化学循环（biogeochemical cycling）的影响仍知之甚少。本研究对置于沿海泻湖（coastal lagoon）沉积物-水界面（sediment-water interface）的塑料与生物塑料（bioplastic）微宇宙体系（microcosms）表面附着的生物膜（biofilms）开展了鸟枪宏基因组测序（shotgun metagenomic sequencing）。群落组成分析结果显示，塑料表面生物膜与陶瓷生物膜对照组无显著差异。与之相反，生物塑料表面生物膜则呈现出显著分化，且以硫酸盐还原微生物（sulfate-reducing microorganisms, SRM）为优势类群。对生物塑料基因库的分析显示，酯酶（esterases）、解聚酶（depolymerases）、腺苷酰硫酸还原酶（adenylyl sulfate reductases, aprBA）以及异化型亚硫酸盐还原酶（dissimilatory sulfite reductases, dsrAB）均发生富集。一株系统发育多样的聚羟基丁酸酯（polyhydroxybutyrate, PHB）解聚酶的富集倍数近乎达到20倍，这表明该基因广泛分布于混合微生物群落中。通过宏基因组基因组重建，在优势硫酸盐还原微生物类群中鉴定出了脱硫弧菌属（Desulfovibrio）、脱硫杆菌科（Desulfobacteraceae）以及脱硫囊菌科（Desulfobulbaceae）的新物种，且这些基因组包含了与生物塑料降解和硫酸盐还原均密切相关的核心基因。研究结果表明，生物塑料可快速且显著地改变底栖微生物多样性与基因库，筛选出参与生物塑料降解与硫酸盐还原的微生物类群。若以生物塑料污染替代塑料污染，且沉积物输入规模较大，则微生物的响应可能会通过刺激硫酸盐还原菌，无意中对底栖生物地球化学活动产生不利影响。