An evolutionarily significant unicellular strategy in response to starvation stress in Dictyostelium social amoebae [v1; ref status: indexed, http://f1000r.es/3hg]

F1000Research

Clément Nizak¹  Minus van Baalen²  Darja Dubravcic² 

[1] Laboratory of Biochemistry, UMR 8231 ESPCI ParisTech/CNRS, PSL Research University, Paris, France;Laboratory of Ecology and Evolution, CNRS UMR7625, Ecole Normale Supérieure, Université Pierre et Marie Curie, Paris Universitas, CNRS, Paris, France;

关键词: Environmental Microbiology;    Microbial Evolution & Genomics;    Microbial Growth & Development;   

DOI  :  10.12688/f1000research.4218.1

来源: DOAJ

【 摘 要 】

The social amoeba Dictyostelium discoideum is widely studied for its multicellular development program as a response to starvation and constitutes a model of choice in microbial cooperation studies. Aggregates of up to 106 cells form fruiting bodies containing two cell types: (i) dormant spores (~80%) that can persist for months in the absence of nutrients, and (ii) dead stalk cells (~20%) that promote the dispersion of the spores towards nutrient-rich areas. It is often overlooked that not all cells aggregate upon starvation. Using a new quantitative approach based on time-lapse fluorescence microscopy and a low ratio of reporting cells, we have quantified this fraction of non-aggregating cells. In realistic starvation conditions, up to 15% of cells do not aggregate, which makes this third cell fate a significant component of the population-level response of social amoebae to starvation. Non-aggregating cells have an advantage over cells in aggregates since they resume growth earlier upon arrival of new nutrients, but have a shorter lifespan under prolonged starvation. We find that phenotypic heterogeneities linked to cell nutritional state bias the representation of cells in the aggregating vs. non-aggregating fractions, and thus regulate population partitioning. Next, we report that the fraction of non-aggregating cells depends on genetic factors that regulate the timing of starvation, signal sensing efficiency and aggregation efficiency. In addition, interactions between clones in mixtures of non-isogenic cells affect the partitioning of each clone into both fractions. We further test the evolutionary significance of the non-aggregating cell fraction. The partitioning of cells into aggregating and non-aggregating fractions is optimal in fluctuating environments with an unpredictable duration of starvation periods. D. discoideum thus constitutes a model system lying at the intersection of microbial cooperation and bet hedging, defining a new frontier in microbiology and evolution studies

【 授权许可】

Unknown