Nakanishi Hiroaki, Seto Kensuke, Takeuchi Nozomu, Kagami Maiko
Graduate School of Environment and Information Sciences, Yokohama National University, Yokohama, Kanagawa, Japan.
Faculty of Environment and Information Sciences, Yokohama National University, Yokohama, Kanagawa, Japan.
Front Microbiol. 2023 Jun 20;14:1201230. doi: 10.3389/fmicb.2023.1201230. eCollection 2023.
Microbial communities are important components of glacier and snowpack ecosystems that influence biogeochemical cycles and snow/ice melt. Recent environmental DNA surveys have revealed that chytrids dominate the fungal communities in polar and alpine snowpacks. These could be parasitic chytrids that infect snow algae as observed microscopically. However, the diversity and phylogenetic position of parasitic chytrids has not been identified due to difficulties in establishing their culture and subsequent DNA sequencing. In this study, we aimed to identify the phylogenetic positions of chytrids infecting the snow algae, , bloomed on snowpacks in Japan.
By linking a microscopically picked single fungal sporangium on a snow algal cell to a subsequent sequence of ribosomal marker genes, we identified three novel lineages with distinct morphologies.
All the three lineages belonged to Mesochytriales, located within "Snow Clade 1", a novel clade consisting of uncultured chytrids from snow-covered environments worldwide. Additionally, putative resting spores of chytrids attached to snow algal cells were observed.
This suggests that chytrids may survive as resting stage in soil after snowmelt. Our study highlights the potential importance of parasitic chytrids that infect snow algal communities.
微生物群落是冰川和积雪生态系统的重要组成部分，影响着生物地球化学循环以及雪/冰融化。最近的环境DNA调查显示，壶菌在极地和高山积雪中的真菌群落中占主导地位。如显微镜观察所示，这些可能是感染雪藻的寄生壶菌。然而，由于难以建立其培养体系及后续的DNA测序，寄生壶菌的多样性和系统发育位置尚未确定。在本研究中，我们旨在确定感染在日本积雪上大量繁殖的雪藻的壶菌的系统发育位置。
通过将在雪藻细胞上显微镜下挑选的单个真菌孢子囊与随后的核糖体标记基因序列相联系，我们鉴定出了三个具有不同形态的新谱系。
所有这三个谱系都属于中壶菌目，位于“雪类群1”内，这是一个由来自世界各地积雪环境的未培养壶菌组成的新类群。此外，还观察到附着在雪藻细胞上的壶菌的假定休眠孢子。
这表明壶菌可能在融雪后以休眠阶段在土壤中存活。我们的研究突出了感染雪藻群落的寄生壶菌的潜在重要性。
