During his career at the PGEC, Sakis made major discoveries in the molecular mechanisms of hormone action. For example, he cloned the gene for ACC synthase. ACC catalyzes the first step in ethylene biosynthesis, and he used it to regulate ripening in tomato. In his most recent paper, a tour-de-force typical of Sakis' s work, he extensively characterized the ACC synthase family in Arabidopsis. He also showed that the hormone auxin rapidly stimulates transcription of certain genes, setting the stage for the explosion of research on auxin signaling, in his lab and in others. He had the vision, with Ron Davis and Joe Ecker, to organize a multinational group to sequence the genome of Arabidopsis thaliana, and specifically carried out a detailed analysis of Chromosome 1.