Single-cell mass spectrometry reveals the importance of genetic diversity and plasticity for phenotypic variation in nitrogen-limited Chlamydomonas

Abstract

Phenotypic variation is vital for microbial populations to survive environmental perturbations. Both genetic and non-genetic factors contribute to an organism's phenotypic variation and therefore its fitness. To investigate the correlation between genetic diversity and phenotypic variation, we applied our recently developed mass spectrometry method that allows for the simultaneous measurement of more than 25 different lipids and pigments with high throughput in the unicellular microalga Chlamydomonas reinhardtii. We monitored the impact of nitrogen limitation on a genetically diverse wild-type strain CC-1690 and two isoclonal isolates from CC-1690 named ANC3 and ANC5. Measuring molecular composition of thousands of single cells at different time points of the experiment allowed us to capture a dynamic picture of the phenotypic composition and adaptation of the populations over time. Although the genetically diverse population maintained phenotypic variation over the whole time course of the experiment, the isoclonal cultures showed higher synchronicity in their phenotypic response. Furthermore, the genetically diverse population showed equal or greater phenotypic variation over the whole time range in multidimensional trait space compared with isoclonal populations. However, along individual trait axes non-genetic variance was higher in isoclonal populations.

The emergence of metabolic heterogeneity and diverse growth responses in isogenic bacterial cells

“…Population diversification is an important mechanism for populations to adapt to fluctuating environments [2,3]; with diversity, there will likely be some individuals that are well suited for a given environment. Previous studies characterized how genetic composition in a population changes slowly through mutations and becomes diverse in environments where nutrients are limited and fluctuate [4][5][6][7][8][9][10][11]. In recent years, it became clear that a genetically identical population can also diversify phenotypically [12][13][14][15][16][17][18][19][20][21][22][23].…”

Identification to species level of live single microalgal cells from plankton samples with matrix-free laser/desorption ionization mass spectrometry

“…The present approach that monitors the metabolome has the potential to generate data about the physiological state of the single cells and thus about the metabolic heterogeneity of a plankton population. The discrimination of nutrient-depleted or aged cells could already be explained with single-cell metabolic profiling (Baumeister et al 2019;Krismer et al 2017). In future studies, a broader set of spectra that also takes into account the cells´ physiological condition could be implemented so that not only the cells identity but also its health status is revealed.…”

Single‐Cell Mass Spectrometry Approaches to Explore Cellular Heterogeneity

“…Microarrays for MS (MAMS), comprised of arrays of hydrophilic micro-wells patterned on ao mniphobic surface,s hows promise for the rapid analysis of up to 169 cells. [74,79] More recently,t his technique was combined with fluidic force microscopy (FluidFM) for the nondestructive and quantitative sampling of cell contents followed by MALDI-MS analysis (Figure 1). This technique was also applied for the analysis of thousands of Chlamydomonas reinhardtii cells.…”

“…This technique was also applied for the analysis of thousands of Chlamydomonas reinhardtii cells. [74,79] More recently,t his technique was combined with fluidic force microscopy (FluidFM) for the nondestructive and quantitative sampling of cell contents followed by MALDI-MS analysis (Figure 1). [80] Ac antilever probe,d riven by an atomic force microscope,w as used to gently extract 1t o3 pL of the cytoplasm from HeLa cells and dispense it onto the MAMS substrate for MALDI-MS analysis.A nother cell-trapping method, based on am icro-well patterned microfluidic chip, was introduced for the high-throughput analysis of phospholipids in single A549 cells by MALDI-MS imaging.…”