TERMIN ENTFÄLLT! (Prof. Ivo Feussner, Universität Göttingen)

Plants employ a multitude of phytohormones to regulate all aspects of their physiology ranging from their development to specific, environment-dependent responses to threats and other cues. The integration of all these signals is governed by different regulatory networks. A key mechanism for the signal integration among different phytohormones is the rapid activation or inactivation of a bioactive phytohormone through its conjugation to amino acids. These reactions are catalyzed by the GRETCHEN HAGEN 3 (GH3) group of enzymes that are found across the green lineage. Arabidopsis thaliana harbors 19 GH3 enzymes, some of which are involved in the metabolism of three key phytohormones: jasmonates, auxin and salicylic acid. However, a number of GH3 enzymes grouping in a Brassicales-specific phylogenetic clade lack functional annotation. This makes the GH3 enzyme family a promising target for the discovery of novel physiological functions through their activity on phytohormones. Furthermore we analyze their functions during evolution by analyzing these enzyme in bryophytes.