Hall Lauren A, Scott Katherine D, Webster Nicole, Kerkhof Lee J, Häggblom Max M
Department of Biochemistry and Microbiology, Rutgers, the State University of New Jersey, New Brunswick, NJ 09801, United States.
Australian Institute of Marine Science, Townsville, QLD 4810, Australia.
ISME J. 2025 Jan 2;19(1). doi: 10.1093/ismejo/wraf113.
Marine sponge holobionts are important contributors to numerous biogeochemical cycles, including the natural organohalogen cycle. Sponges produce diverse brominated secondary metabolites, which select for a population of anaerobic debrominating bacteria within the sponge body. Sponge microbiomes can be host-specific, but the selection and host-specificity of debrominating bacteria are unknown currently. In this study, we used nanopore long-read sequencing of nearly full-length ribosomal RNA operons to evaluate host-specificity of the Great Barrier Reef sponge microbiomes at the strain level and to determine if host specificity extends to sponge-associated dehalogenating bacteria. Reductive debromination activity was observed in anaerobic enrichment cultures established from all Great Barrier Reef sponges. Even though other bacterial symbionts of interest, including Nitrospira spp. and Ca. Synechococcus spp. demonstrated strong host-specificity, Desulfoluna spp., a key sponge-associated dehalogenating bacterium showed no evidence of host-specificity. This suggests different modes of transmission and/or retention of different members of the sponge microbiome residing within the same host species. These findings expand our understanding of how sponge microbiomes are assembled and the relationship between the host and individual bacterial strains.
海洋海绵共生体对包括天然有机卤素循环在内的众多生物地球化学循环都有重要贡献。海绵产生多种含溴次生代谢产物，这些产物会在海绵体内筛选出一群厌氧脱溴细菌。海绵微生物群可能具有宿主特异性，但目前脱溴细菌的选择及其宿主特异性尚不清楚。在本研究中，我们使用了近乎全长核糖体RNA操纵子的纳米孔长读长测序技术，在菌株水平上评估大堡礁海绵微生物群的宿主特异性，并确定宿主特异性是否扩展到与海绵相关的脱卤细菌。在从所有大堡礁海绵建立的厌氧富集培养物中都观察到了还原脱溴活性。尽管其他感兴趣的细菌共生体，包括硝化螺旋菌属和聚球藻属表现出很强的宿主特异性，但作为关键的与海绵相关的脱卤细菌的脱硫月球菌属却没有表现出宿主特异性的证据。这表明同一宿主物种内海绵微生物群不同成员的传播和/或留存方式不同。这些发现扩展了我们对海绵微生物群如何组装以及宿主与单个细菌菌株之间关系的理解。
