Origins and metabolism of formate in higher plants

Formate, a simple one-carbon compound, is readily metabolized in plant tiss ues. In greening potato tubers, similar to some procaryotes, formate is dir ectly synthesized via a ferredoxin-dependent fixation of CO2, serving as th e main precursor for carbon skeletons in biosynthetic pathways. In other pl ant species and tissues, formate appears as a side-product of photorespirat ion and of fermentation pathways, but possibly also as a product of direct CO2 reduction in chloroplasts. Formate metabolism is closely related to ser ine synthesis and to all subsequent reactions originating from serine. Form ate may have a role in biosynthesis of numerous compounds, in energetic met abolism and in si,signal transduction pathways related to stress response. This review summarizes the current state of formate research, physiological /biochemical and molecular aspects. (C) Elsevier, Paris.