Table_2_Carapace microbiota in American lobsters (Homarus americanus) associated with epizootic shell disease and the green gland.XLSX

Epizootic Shell Disease (ESD) has posed a great threat, both ecologically and economically, to the American lobster population of Long Island Sound since its emergence in the late 1990s. Because of the polymicrobial nature of carapace infections, causative agents for ESD remain unclear. In this study, we aimed to identify carapace microbiota associated with ESD and its potential impact on the microbiota of internal organs (green gland, hepatopancreas, intestine, and testis) using high-throughput 16S rRNA gene sequencing. We found that lobsters with ESD harbored specific carapace microbiota characterized by high abundance of Aquimarina, which was significantly different from healthy lobsters. PICRUSt analysis showed that metabolic pathways such as amino acid metabolism were enriched in the carapace microbiota of lobsters with ESD. Aquimarina, Halocynthiibacter, and Tenacibaculum were identified as core carapace bacteria associated with ESD. Particularly, Aquimarina and Halocynthiibacter were detected in the green gland, hepatopancreas, and testis of lobsters with ESD, but were absent from all internal organs tested in healthy lobsters. Hierarchical clustering analysis revealed that the carapace microbiota of lobsters with ESD was closely related to the green gland microbiota, whereas the carapace microbiota of healthy lobsters was more similar to the testis microbiota. Taken together, our findings suggest that ESD is associated with alterations in the structure and function of carapace microbiota, which may facilitate the invasion of bacteria into the green gland.

流行性贝壳病（Epizootic Shell Disease, ESD）自20世纪90年代末出现以来，已对长岛湾的美洲龙虾种群造成了生态与经济双重威胁。由于甲壳感染具有多微生物特性，ESD的致病因子仍不明确。本研究采用高通量16S rRNA基因测序技术，旨在鉴定与ESD相关的甲壳微生物群，并探究其对龙虾内脏器官（绿腺、肝胰腺、肠道和睾丸）微生物群的潜在影响。研究发现，患ESD的龙虾携带以海生单胞菌属（Aquimarina）高丰度为特征的特异性甲壳微生物群，该群落与健康龙虾存在显著差异。PICRUSt分析显示，患ESD的龙虾甲壳微生物群中富集了氨基酸代谢等代谢通路。海生单胞菌属（Aquimarina）、海鞘杆菌属（Halocynthiibacter）和屈挠杆菌属（Tenacibaculum）被鉴定为与ESD相关的核心甲壳菌群。尤为值得注意的是，海生单胞菌属（Aquimarina）和海鞘杆菌属（Halocynthiibacter）在患ESD龙虾的绿腺、肝胰腺和睾丸中均有检出，而健康龙虾的所有受试内脏器官中均未发现此类菌群。层次聚类分析结果显示，患ESD龙虾的甲壳微生物群与绿腺微生物群亲缘关系较近，而健康龙虾的甲壳微生物群则与睾丸微生物群更为相似。综上，本研究结果表明，ESD与甲壳微生物群的结构和功能改变密切相关，该改变可能促进细菌侵入绿腺。