Bhattacharya Dhruba, Jiya Namrata, Mondal Sangita, Acharya Agnita, Chatterjee Abhijit, Bakshi Utpal, Sharma Avinash, Ghosh Abhrajyoti
Department of Biological Sciences, Bose Institute, Kolkata, India.
BRIC-National Centre for Cell Science, Pune, India.
Microbiol Spectr. 2025 Aug 27:e0214925. doi: 10.1128/spectrum.02149-25.
Sponges serve as the natural cleaner in diverse aquatic ecosystems, harboring diverse microbial communities and forming a highly specialized holobiont. The present study provides the first insights into the bacterial communities associated with freshwater sponges of Sundarban, highlighting their distinct microbial community composition compared to the surrounding water using 16S rRNA gene-based metataxonomic analyses. The analysis encompassing six sponge species collected from Sagar Island and Ghoramara revealed distinct variations in microbial abundance and diversity compared to their ambient water, suggesting selective bacterial associations with the sponges. The sponge species displayed a varied abundance of bacterial taxa across different species and locations. Furthermore, significantly greater concentrations of potentially toxic elements (PTEs) were observed in sponges when compared with corresponding water samples, thereby suggesting the bioaccumulation capability of these sponges. Functional profiling of bacterial communities in sponge and water samples revealed enrichment of various metabolic pathways linked to metal ion transport and resistance, as well as antimicrobial resistance in the sponges, suggesting an adaptive response to environmental stressors. The abundance of diverse metal ion regulators and transporters underscores the ecologically significant function of sponge-associated bacterial communities in metal ion resistance, placing the sponges as promising bioindicators for monitoring polluted aquatic ecosystems.IMPORTANCEFreshwater sponges play an essential role as natural biofilters in aquatic ecosystems, effectively purifying water. These sponges harbor unique microbial communities, forming a holobiont that is key to their ecological function. This study offers new insights into the bacterial communities associated with freshwater sponges from the Sundarbans, a previously underexplored region. Using 16S rRNA gene-based metataxonomic analyses, we compared the bacterial diversity of six sponge species from Sagar Island and Ghoramara to that of surrounding water. Our results reveal distinct bacterial associations within sponges, different from the ambient water's microbial composition. Notably, sponge concentrations of potentially toxic elements (PTEs) were much higher than in the surrounding water, highlighting their bioaccumulation capacity. Functional profiling of sponge-associated bacteria revealed genes related to metal ion transport and antimicrobial resistance, suggesting adaptive responses to environmental stress. This research enhances our understanding of sponge microbiomes and their potential for bioremediation, particularly for removing heavy metals from polluted water.
海绵是多种水生生态系统中的天然清洁工，它们拥有多样的微生物群落，并形成了高度专业化的共生体。本研究首次深入探究了与孙德尔本斯淡水海绵相关的细菌群落，通过基于16S rRNA基因的宏分类分析，突出了它们与周围水体相比独特的微生物群落组成。对从萨加尔岛和戈勒马拉采集的六种海绵物种的分析表明，与周围水体相比，它们的微生物丰度和多样性存在明显差异，这表明海绵与细菌之间存在选择性关联。不同物种和地点的海绵物种显示出不同的细菌分类群丰度。此外，与相应水样相比，在海绵中观察到潜在有毒元素（PTEs）的浓度显著更高，从而表明这些海绵具有生物累积能力。对海绵和水样中细菌群落的功能分析表明，与金属离子运输和抗性以及海绵中的抗微生物抗性相关的各种代谢途径得到了富集，这表明对环境压力源的适应性反应。多种金属离子调节剂和转运蛋白的丰度强调了与海绵相关的细菌群落在金属离子抗性方面具有重要的生态功能，使海绵成为监测污染水生生态系统的有前途的生物指标。
重要性
淡水海绵在水生生态系统中作为天然生物过滤器发挥着重要作用，有效地净化水体。这些海绵拥有独特的微生物群落，形成了一个对其生态功能至关重要的共生体。本研究为来自孙德尔本斯（一个此前未被充分探索的地区）的淡水海绵相关细菌群落提供了新的见解。通过基于16S rRNA基因的宏分类分析，我们比较了来自萨加尔岛和戈勒马拉的六种海绵物种与周围水体的细菌多样性。我们的结果揭示了海绵内部独特的细菌关联，不同于周围水体的微生物组成。值得注意的是，海绵中潜在有毒元素（PTEs）的浓度远高于周围水体，突出了它们的生物累积能力。对与海绵相关细菌的功能分析揭示了与金属离子运输和抗微生物抗性相关的基因，表明对环境压力的适应性反应。这项研究增进了我们对海绵微生物群及其生物修复潜力的理解，特别是在从污染水体中去除重金属方面。
