Vitamin E (Tocopherol) and phytyl esters in plants

Research Activities
Prof. Dr. Peter Dörmann

Tocopherol (vitamin E) is a lipid antioxidant involved in scavenging reactive oxygen species in plants and animals. A tocopherol-deficient mutant identified in our laboratory, vitamin E deficient mutant 1 (vte1), is defective in tocopherol cyclase and thus completely devoid of tocopherol (Porfirova et al., 2002). Tocopherol deficiency causes increased oxidative stress in thylakoid membranes. Reduction in tocopherol can be compensated for by zeaxanthin, a carotenoid with antioxidative activity involved in the protection of the photosynthetic complexes against high light, substantiating the adaptive role of antioxidants in biological tissues (Havaux et al., 2005).

Fatty acid phytyl esters represent a compound class in plants related to tocopherol as these two substances contain phytol, a long chain alcohol derived from chlorophyll (Ischebeck et al., 2006). Fatty acid phytyl esters only accumulate during stress and senescence in plants and transiently store fatty acids and phytol derived from galactolipid and chlorophyll degradation, respectively (Lippold et al., 2012). We study the relationship between chlorophyll degradation and the synthesis of tocopherol fatty acid synthesis.


Figure 2: Pathway for tocopherol synthesis in chloroplasts of plants.

Figure 3: Senescence is delayed in the pes1pes2 double mutant deficient in phytyl ester synthesis. Detached leaves of wild type and the pes1pes2 mutant were incubated in darkness for the time indicated.