Abstract :
[en] Natural variation among individuals and populations exist in all species, playing key roles in response to environmental stress and adaptation. This natural variation can be exploited to identify genetic variants affecting important biological processes or controlling traits of economical interest in sectors such as agriculture and healthcare.
Micro- and macro-nutrients have a wide range of functions in photosynthetic organisms and mineral nutrition plays thus a sizable role in biomass production. To maintain nutrient concentrations inside the cell within physiological limits and prevent the detrimental effects of deficiency or excess, complex homeostatic networks have evolved in photosynthetic cells. Chlamydomonas is an eukaryotic photosynthetic model for studying such mechanisms.
In this work, twenty-four Chlamydomonas strains, comprising field isolates and laboratory strains, are used to examine intraspecific differences in nutrient homeostasis. Mixotrophy (TAP medium) isused as full nutrition control, and 10 deprivation conditions were tested: autotrophy (TMP medium, -acetate), macronutrient deprivation (-Ca, -Mg, -N, -P, -S), and micronutrient deprivation (-Cu, -Fe, -Mn, -Zn). Growth and the ionome are quantified upon 96h culture in deprivation media.
Growth differences among strains are observable, but relatively limited, whereas important variation in cellular nutrient accumulation is observed. Interestingly, similar growth is accompanied by highly divergent ionome among a number of strains, pointing towards different deprivation management strategies. Further characterization of this variation photosynthesis efficiency measurements will be presented.
