Renberg L, Johansson AI, Shutova T, Stenlund H, Aksmann A, Raven JA, Gardeström P, Moritz T, Samuelsson G
A metabolomic approach to study major metabolite changes during acclimation to limiting CO2 in Chlamydomonas reinhardtii
Plant Physiology: 2010 154:187-196

Abstract
Using a gas chromatography-mass spectrometry-time of flighttechnique, we determined major metabolite changes during inductionof the carbon-concentrating mechanism in the unicellular greenalga Chlamydomonas reinhardtii. In total, 128 metabolites withsignificant differences between high- and low-CO2-grown cellswere detected, of which 82 were wholly or partially identified,including amino acids, lipids, and carbohydrates. In a 24-htime course experiment, we show that the amino acids serineand phenylalanine increase transiently while aspartate and glutamatedecrease after transfer to low CO2. The biggest differenceswere typically observed 3 h after transfer to low-CO2 conditions.Therefore, we made a careful metabolomic examination at the3-h time point, comparing low-CO2 treatment to high-CO2 control.Five metabolites involved in photorespiration, 11 amino acids,and one lipid were increased, while six amino acids and, interestingly,21 lipids were significantly lower. Our conclusion is that themetabolic pattern during early induction of the carbon-concentratingmechanism fit a model where photorespiration is increasing.

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