Carbon dioxide induces minor antioxidant responses in Eucalyptus urophylla chloroplasts

Abstract

Minor effect on the chloroplast antioxidant proteins was detected in Eucalyptus urophylla cultivated in high-CO2 atmosphere. Global climate change can significantly alter plant cell metabolism. A higher atmospheric CO2 scenario may be beneficial for C3 plants through the stimulation of photosynthesis. This predicted increase in the rate of carbon assimilation may also increase the expression of enzymes involved in the antioxidant cellular defense. Here, we studied the responses of the chloroplastic antioxidant system of Eucalyptus urophylla plants cultivated in a high-CO2 condition. Plants exposed to a high concentration (980 ppm) of CO2 showed an increase in the H2O2 concentration and MDA content in relation to those cultivated at 410 and 680 ppm. With the discovery proteomics approach used herein, we identified 19 chloroplastic antioxidant proteoforms and pinpointed differentially regulated isoforms of an ascorbate peroxidase and a superoxidase dismutase upon cultivation in a high-CO2 atmosphere. Our data indicate that the CO2 stimulus induces only minor changes in the antioxidant metabolism of E. urophylla chloroplasts.