Steven Graham Ball, an agricultural engineer, holds a Doctor-Engineer thesis awarded by the Faculty of Agricultural Sciences of the State in Gembloux (Belgium) in 1984. This research was conducted at NIH (Bethesda – Md) under the supervision of R. B. Wickner and focused on the study of the molecular genetics of a mycovirus living in symbiosis within yeast. Appointed as a professor in France in 1987 (CNU section 65: microbiology/cell biology), he conducted his entire research career within the CNRS/University of Lille UMR of Structural and Functional Glycobiology. Since 1986, he has focused his interest on the function and evolution of reserve polysaccharide metabolism, first in yeast and very quickly thereafter in the model green unicellular alga Chlamydomonas reinhardtii. The team led by Steven Ball is internationally recognized for having highlighted the major functions distinguishing starch granule formation in plants relative to the pre-existing eukaryotic glycogen metabolism. More recently, Steven Ball proposed the precise role played by Chlamydia-type intracellular pathogens in the establishment of symbiotic carbon flux during plastidial endosymbiosis. By analogy with the plastid, he currently proposes for mitochondria that biotic interactions of the same type governed the metabolic integration of this organelle. He served as an editor for Plant Physiology and coordinated the publication of a special issue of this journal dedicated to microalgal genomics. He has been a member on several occasions of evaluation bodies at CNRS (CoNRS Integrative Plant Biology section) and at FNRS (Belgium) (Plant Biology commission). He supervised 18 theses and was an invited speaker at conferences or seminars on more than 100 occasions, including 3 times in a plenary session of a Gordon Conference.

> steven.ball@univ-lille.fr