Graduate School of Life and Environmental Sciences, University of Yamanashi.
Graduate School of Engineering, University of Yamanashi.
Microbes Environ. 2024;39(3). doi: 10.1264/jsme2.ME24019.
The "duckweed-microbes co-cultivation method" is a microbial isolation technique that effectively recovers diverse microbes, including rarely cultivated bacterial phyla, from environmental samples. In this method, aseptic duckweed and microbes collected from an environmental sample are co-cultivated for several days, and duckweed-associated microbes are then isolated from its roots using a conventional agar plate-based cultivation method. We herein propose several improvements to the method in order to specifically obtain members of the rarely cultivated bacterial phylum, Verrucomicrobiota. In systems using river water as the inoculum, the marked enrichment of Verrucomicrobiota was observed after 10 days of co-cultivation, particularly in the roots and co-cultivated media. We also successfully isolated 44 strains belonging to subdivisions 1, 3, and 4 of the phylum Verrucomicrobiota from these systems. This was achieved by changing the concentration of nitrogen in the co-cultivation medium, which is known to affect duckweed growth and/or metabolism, and by subjecting the fronds and co-cultivated media as well as the roots after co-cultivation to microbial isolation.
“浮萍-微生物共培养方法”是一种微生物分离技术，可从环境样本中有效回收包括罕见培养细菌门在内的多种微生物。在该方法中，无菌浮萍和从环境样本中收集的微生物进行数天的共培养，然后使用常规的琼脂平板培养方法从其根部分离浮萍相关微生物。为了专门获得罕见培养细菌门 Verrucomicrobiota 的成员，我们对该方法进行了几项改进。在以河水作为接种物的系统中，共培养 10 天后观察到 Verrucomicrobiota 的明显富集，特别是在根部和共培养介质中。我们还成功地从这些系统中分离出属于 Verrucomicrobiota 门的亚群 1、3 和 4 的 44 株菌株。通过改变共培养介质中氮的浓度来实现这一点，已知氮的浓度会影响浮萍的生长和/或代谢，并且通过对共培养后的叶片和共培养介质以及根部进行微生物分离来实现这一点。
