**About the Editors**

**Stefan Timm** has conducted seminal research on the identification of unknown components of plant photorespiration, including the genetic establishment of a cytosolic bypass, and how photorespiration is imbedded within the central plant carbon metabolism. During recent years, his research has mainly focused on the regulatory impact of photorespiratory metabolites on photosynthetic carbon assimilation, particularly the Calvin Benson cycle. Moreover, he was involved in pioneering the concept that increases the activities of specific photorespiratory enzymes, retrieving the potential to enhance the flux through photorespiration, thereby stimulating photosynthesis and growth. The effects of altered metabolite levels on transcriptional and post-translational regulation are also included in his interests.

**St ´ephanie Arrivault**'s research is mainly focused on the elucidation of carbon fluxes in C<sup>3</sup> and C<sup>4</sup> photosynthesis by the use of dynamic <sup>13</sup>CO<sup>2</sup> labelling coupled with LC-MS/MS quantification.
