Sabine Zachgo, Botany, University of Osnabrück, Germany
Annelie Carlsbecker, Physiological Botany / Organismal Biology, UU
Lecture hall A281, BioCentre, Ultuna
14:00 - 15:00
Comparative analysis of ROXYs, land-plant specific glutaredoxins, in Arabidopsis and the liverwort Marchantia

Glutaredoxins (GRXs) are ubiquitous oxidoreductase enzymes, which catalyze the reversible reduction of disulfide bonds in their target proteins. Three major classes of GRX genes exist and CPYC, CGFS classes are present in all pro- and eukaryote species, whereas CC-type class GRXs are land-plant specific. Until recently, GRXs were known to be mainly involved in oxidative stress responses. Analysis of the Arabidopsis thaliana CC-type GRXs ROXY1 and ROXY2 revealed a novel GRX function, namely a participation in petal and anther development. The TGA transcription factor PERIANTHIA (PAN) was identified as a ROXY1 interaction partner and also controls petal development. PAN protein binding to cis-regulatory target motifs was analyzed by redox-EMSAs and implications from these data will be discussed. Whereas sizes of the CPYC and CGFS classes remained rather similar throughout land plant evolution, exclusively the CC-type GRX class expanded strongly. Gene duplications facilitate sub- and neofunctionalization processes and this might have contributed to the sequestration of land plant-specific CC-type GRXs into novel functions during angiosperm evolution. However, given the large ROXY and TGA gene family sizes in angiosperms, redundancy effects often hamper their functional analyses. The novel basal land plant model system Marchantia polymorpha, a liverwort, comprises most of the angiosperm gene families with lower gene numbers and its advantages to unravel ancestral gene functions will be presented.