Phenotypic plasticity in freshwater picocyanobacteria

作者：Huber Paula; Diovisalvi Nadia; Ferraro Marcela; Metz Sebastian; Lagomarsino Leonardo; Eugenia Llames Maria; Royo Llonch Marta; Bustingorry Jose; Escaray Roberto; Acinas Silvia G; Gasol Josep M; Unrein Fernando

来源：Environmental Microbiology, 2017, 19(3): 1120-1133.

DOI：10.1111/1462-2920.13638

<jats:title>Summary</jats:title><jats:p>Picocyanobacteria can occur as single‐cell (Pcy) or as colonies (CPcy). Published evidence suggests that some Pcy strains have the capability to aggregate under certain culture conditions, however this has not been demonstrated to occur in natural environments. We investigated whether the Pcy and CPcy belong to the same species (i.e. phylotype), and the factors that determine their morphological and genetic variability in a hypertrophic shallow lake dominated by picocyanobacteria. Six main different morphologies and &gt;30 phylotypes were observed. All sequences retrieved belonged to the ‘<jats:italic>Anathece + Cyanobium</jats:italic>’ clade (Synechococcales) that are known to have the capability of aggregation/disaggregation. The temporal variation of picocyanobacteria morphotype composition was weakly correlated with the DGGE temporal pattern, and could be explained by the composition of the zooplankton assemblage. Laboratory experiments confirmed that the small cladoceran <jats:italic>Bosmina</jats:italic> favoured the dominance of CPcy, i.e. <jats:italic>Cyanodictyon</jats:italic> doubled the size of the colonies when present, most likely through the aggregation of single‐cell picocyanobacteria into colonies. Flow cytometry cell sorting and 16S rRNA + ITS sequencing of the Pcy and CPcy cytometrically‐defined populations revealed that some phylotypes could be found in both sorted populations, suggesting phenotypic plasticity in which various Synechococcales phylotypes could be found <jats:italic>in situ</jats:italic> either as single‐cells or as colonies.</jats:p>

• 出版日期2017-3