fmicb-12-700637 July 21, 2021 Time: 17:27 # 1 ORIGINAL RESEARCH published: 27 July 2021 doi: 10.3389/fmicb.2021.700637 Cultivation of Dominant Freshwater Bacterioplankton Lineages Using a High-Throughput Dilution-to-Extinction Culturing Approach Over a 1-Year Period Suhyun Kim1, Md. Rashedul Islam2, Ilnam Kang3* and Jang-Cheon Cho1* 1 Department of Biological Sciences and Bioengineering, Inha University, Incheon, South Korea, 2 Bacteriophage Biology Laboratory, Guelph Research and Development Centre, Agriculture and Agri-Food Canada, Guelph, ON, Canada, 3 Department of Biological Sciences, Center for Molecular and Cell Biology, Inha University, Incheon, South Korea Although many culture-independent molecular analyses have elucidated a great diversity of freshwater bacterioplankton, the ecophysiological characteristics of several abundant Edited by: freshwater bacterial groups are largely unknown due to the scarcity of cultured Bin-Bin Xie, representatives. Therefore, a high-throughput dilution-to-extinction culturing (HTC) Shandong University, China approach was implemented herein to enable the culture of these bacterioplankton Reviewed by: Annette Bollmann, lineages using water samples collected at various seasons and depths from Lake Miami University, United States Soyang, an oligotrophic reservoir located in South Korea. Some predominant freshwater Sarahi L. Garcia, Stockholm University, Sweden bacteria have been isolated from Lake Soyang via HTC (e.g., the acI lineage); however, *Correspondence: large-scale HTC studies encompassing different seasons and water depths have not Ilnam Kang been documented yet. In this HTC approach, bacterial growth was detected in 14% of
[email protected] 5,376 inoculated wells. Further, phylogenetic analyses of 16S rRNA genes from a total Jang-Cheon Cho
[email protected] of 605 putatively axenic bacterial cultures indicated that the HTC isolates were largely composed of Actinobacteria, Bacteroidetes, Alphaproteobacteria, Betaproteobacteria, Specialty section: Gammaproteobacteria, and Verrucomicrobia.