Manohar Cathrine Sumathi, Menezes Larissa Danielle, Ramasamy Kesava Priyan, Meena Ram M
Biological Oceanography Division, CSIR - National Institute of Oceanography, Dona Paula, Goa 403 004, India.
Can J Microbiol. 2015 Mar;61(3):217-26. doi: 10.1139/cjm-2014-0507. Epub 2014 Dec 12.
Reports on the active role of fungi as denitrifiers in terrestrial ecosystems have stimulated an interest in the study of the role of fungi in oxygen-deficient marine systems. In this study, the culturable diversity of fungi was investigated from 4 stations within the permanent, oceanic, oxygen minimum zone of the Arabian Sea. The isolated cultures grouped within the 2 major fungal phyla Ascomycota and Basidiomycota; diversity estimates in the stations sampled indicated that the diversity of the oxygen-depleted environments is less than that of mangrove regions and deep-sea habitats. Phylogenetic analyses of 18S rRNA sequences revealed a few divergent isolates that clustered with environmental sequences previously obtained by others. This is significant, as these isolates represent phylotypes that so far were known only from metagenomic studies and are of phylogenetic importance. Nitrate reduction activity, the first step in the denitrification process, was recorded for isolates under simulated anoxic, deep-sea conditions showing ecological significance of fungi in the oxygen-depleted habitats. This report increases our understanding of fungal diversity in unique, poorly studied habitats and underlines the importance of fungi in the oxygen-depleted environments.
关于真菌在陆地生态系统中作为反硝化菌的积极作用的报告激发了人们对研究真菌在缺氧海洋系统中作用的兴趣。在本研究中，从阿拉伯海永久性大洋氧含量最低区域内的4个站点调查了可培养真菌的多样性。分离培养物归入子囊菌门和担子菌门这两个主要真菌门；所采样站点的多样性估计表明，缺氧环境的多样性低于红树林区域和深海栖息地。对18S rRNA序列的系统发育分析揭示了一些与其他人先前获得的环境序列聚类的不同分离株。这很重要，因为这些分离株代表了迄今为止仅从宏基因组研究中已知的系统发育型，具有系统发育重要性。在模拟缺氧深海条件下，记录到分离株的硝酸盐还原活性，这是反硝化过程的第一步，表明真菌在缺氧栖息地具有生态意义。本报告增进了我们对独特且研究较少的栖息地中真菌多样性的理解，并强调了真菌在缺氧环境中的重要性。
