The interplay between photorespiration and iron deficiency : a preliminary investigation

Iron (Fe) is an essential element for living organisms being a cofactor of many metabolic processes. The most noticeable effect of Fe deficiency in leaves is a marked chlorosis caused by a lack in chlorophyll biosynthesis which results in reduction of photosynthesis and induction of oxidative stress. Photorespiration can be considered as a cycle which helps to defend plants from those impairments. Metabolic characterization of Cucumis sativus L. plants grown at different Fe concentration was performed to investigate the interplay among Fe deficiency and photorespiration. In vivo analysis of photosynthetic and chlorophyll fluorescence parameters suggest limitations in photosynthesis and induction of other energy dissipation processes. The activity of Fe-dependent enzymes involved in photorespiration was lower in Fe-deprived plants. Purification of the peroxisomal fraction to carry out Western Blot analysis of enzymes belonging to photorespiration was undertaken. Our data suggest that the imbalance induced by Fe deficiency may be balanced by increased rate of photorespiration. Future perspective will be the purification and characterization of Fe-deficient chloroplasts and mitochondria.