Plant metabolism and growth are influenced by many environmental parameters, e.g. light intensity, temperature and the availability of water and minerals. Under unfavourable conditions, cytotoxic amounts of reactive oxygen species can be formed inside cells. Chloroplasts are especially prone to formation of reactive oxygen species. A network of low molecular weight antioxidants and antioxidant enzymes protects them against photooxidative stress.
Since all enzymes involved in antioxidant protection are nuclear encoded, regulation of the chloroplast antioxidant system depends on chloroplast-to-nucleus signalling and regulation of nuclear gene expression. Gene expression studies demonstrated that plastid antioxidant protection responds to environmetal and developmental signals. However, the signalling mechanisms are still widely unknown. To understand how plants cope with unfavourable variations in the environment and protect themselves efficiently against photooxidative damage, our research projects focusses on the following topics:
- Which signals coordinate expression of antioxidant enzymes in the nucleus?
- How are plastid signals transmitted to the nucleus?
- Which transcription factors control gene expression? What are their target elements?
- What are the differences in the response systems of ecotypes and species, which adapted to different habitats?
For a quick overview, we recommend the following review articles:
Baier M, Pitsch NT, Mellenthin M, Guo W (2010) Regulation of genes encoding chloroplast antioxidant enzymes in comparison to regulation of the extra-plastidic antioxidant defense system. In: Ascorbate-glutathione pathway and stress tolerance in plants. Anjum NA, Chan M-T, Umar S (eds) Springer (in press)
Baier M, Dietz K-J (2005) Chloroplasts as source and target of cellular redox regulation: A discussion of chloroplast-to-nucleus signals in context of plant physiology and evolution. J. Exp. Bot. 56, 1449 - 1462
Baier M, Dietz K-J (1998) The costs and benefits of oxygen for photosynthesizing plant cells. Prog. Bot. 60, 282 - 314