Hu Guangzhao, Zhong Maosheng, Zhang Changhao, Lai Hongfu, Breyer Eva, Fang Jiasong, Yu Xi
Shanghai Engineering Research Center of Hadal Science and Technology, College of Oceanography and Ecological Science, Shanghai Ocean University, Shanghai, China.
Appl Environ Microbiol. 2025 Aug 12:e0092125. doi: 10.1128/aem.00921-25.
The hadal zone, one of Earth's most extreme ecosystems, harbors diverse and unique microbial communities adapted to its harsh environmental conditions, including high hydrostatic pressure (HHP) and low temperatures. Within these communities, deep-sea fungi play a critical role in geochemical cycling and marine ecosystem functioning; however, research on their cultivable strains and adaptation mechanism remains scarce. In this study, the piezo-tolerant fungus DM1, isolated from the Mariana Trench sediments (10,898 m), was selected as a representative strain. A comprehensive genome analysis using high-throughput sequencing revealed a genome size of 34.5 Mb, with 12,241 predicted genes. Functional annotations across multiple databases identified a substantial number of pathways associated with environmental adaptations, including extensive carbohydrate, amino acid, sulfur, and nitrogen metabolic pathways. Among them, the HOG (high-osmolarity glycerol) signal pathway, which responds to external stimuli, was indicated to play a crucial role. To study the HOG signal pathways in more detail, we developed a knockout technique for and constructed a mutant strain (Δ). The Δ strain displayed notable differences in colony phenotype, spore production, secondary metabolites, and oxidative stress tolerance compared to the wild type. Furthermore, the gene was found to regulate reactive oxygen species (ROS) and ATP levels in response to osmotic pressure and HHP, suggesting a role of in the fungal adaptation to this extreme environment. Our study serves as an ideal candidate for exploring gene functions in extreme microorganisms and carries significant implications for understanding the adaptive mechanisms of hadal microorganisms.
Research on the genomes and gene functions of hadal zone fungi is crucial for understanding life's adaptation to extreme environments. However, current studies on constructing genetic operation systems for marine-derived filamentous fungi are scarce, and research on HHP environments in related fields is virtually non-existent. Our study highlights the critical role of the HOG-mediated pathway in regulating stress responses and metabolic processes in extremophiles, a regulatory mechanism that had not been previously investigated under HHP conditions. Notably, the whole-genome annotation of the hadal fungus DM1 advances our understanding of the life processes of hadal fungi. The development of gene knockout technology, combined with insights into stress adaptation and metabolic regulation in strain DM1, provides a strong foundation for future research and biotechnological applications.
超深渊带是地球上最极端的生态系统之一，拥有适应其恶劣环境条件（包括高静水压力（HHP）和低温）的多样且独特的微生物群落。在这些群落中，深海真菌在地球化学循环和海洋生态系统功能中发挥着关键作用；然而，关于其可培养菌株及其适应机制的研究仍然匮乏。在本研究中，从马里亚纳海沟沉积物（10898米）中分离出的耐压真菌DM1被选为代表性菌株。使用高通量测序进行的全面基因组分析显示，其基因组大小为34.5兆碱基，预测基因有12241个。通过多个数据库进行的功能注释确定了大量与环境适应相关的途径，包括广泛的碳水化合物、氨基酸、硫和氮代谢途径。其中，响应外部刺激的高渗甘油（HOG）信号通路被表明发挥着关键作用。为了更详细地研究HOG信号通路，我们开发了针对[具体基因名称未给出]的基因敲除技术，并构建了一个[具体基因名称未给出]突变菌株（Δ[具体基因名称未给出]）。与野生型相比，Δ[具体基因名称未给出]菌株在菌落表型、孢子产生、次级代谢产物和氧化应激耐受性方面表现出显著差异。此外，发现[具体基因名称未给出]基因可响应渗透压和高静水压力调节活性氧（ROS）和ATP水平，表明[具体基因名称未给出]在真菌适应这种极端环境中发挥作用。我们的研究是探索极端微生物基因功能的理想候选对象，对理解超深渊微生物的适应机制具有重要意义。
对超深渊带真菌的基因组和基因功能进行研究对于理解生命对极端环境的适应至关重要。然而，目前关于构建海洋来源丝状真菌遗传操作系统的研究匮乏，相关领域中关于高静水压力环境的研究几乎不存在。我们的研究突出了HOG介导的途径在调节嗜极端微生物应激反应和代谢过程中的关键作用，这是一种此前在高静水压力条件下未被研究过的调节机制。值得注意的是，超深渊真菌DM1的全基因组注释增进了我们对超深渊真菌生命过程的理解。基因敲除技术的开发，结合对DM1菌株应激适应和代谢调节的深入了解，为未来的研究和生物技术应用提供了坚实基础。
