Rapid establishment of clonal isolates of freshwater autotrophic picoplankton by single-cell and single-colony sorting

Abstract

We describe single-cell and single-colony sorting protocols which allowed for rapid establishment of a diverse culture collection of clonal autotrophic picoplankton (APP) isolates originating from oligotrophic and oligo-mesotrophic subalpine lakes. Overall sort recoveries, expressed as the percentage of sorted microwells exhibiting APP growth, ranged from 5% to 17% depending on the type of APP, but the growth success varied greatly (from 0% to 68%) depending on the origin of the sorted sample. We applied two direct sequencing and two denaturing gradient gel electrophoresis (DGGE) protocols to identify and characterize the genetic purity of 21 of our picocyanobacteria cultures, namely, direct..