Poster: Lipids & related molecules

Abs # 311: Genome Wide RNA Expression and Metabolic Analysis of high light adaptation in wild type, tocopherol minus (vte1), and complemented (pvte-vte1) mutants of Arabidopsis thaliana

Presenter:	Coughlan, Sean , sean_coughlan@agilent.com
Authors	Coughlan, Sean  (A)   Bergmuller, Eveline  (B)   Kanwischer, Marion  (B)   Kopka, Joachim  (B)   Doerman, Peter  (B)   Cahoon, Edgar B (C)
Affiliations:	(A): Agilent Technologies (B): Max-Planck-Institute of Molecular Plant Physiology (C): USDA/ARS Unit at the Donald Danforth Plant Science Center

The vitamin E family of prenyllipid antioxidants (tocopherols and tocotrienols) occur only in photosynthetic organisms and are thought to play a role in protection against oxidative stress. The elucidation of the biosynthetic pathway of alpha tocopherol biosynthesis using Arabidopsis thaliana reverse genetics, has also given us a number of defined tocopherol minus Arabidopsis mutants, which are ideal tools to study the biological role of tocopherols in the prevention of photo-oxidative damage. The recently identified vte1 mutant of Arabidopsis , which is deficient in tocopherol cyclase enzymatic activity, displays an apparently normal phenotype under standard growth conditions. We have utilized genome wide RNA expression analysis and comprehensive metabolic profiling of leaf samples from both wild type and vte1 mutant and vte1 mutant plants transformed with a 35S vte1 over-expression contruct (complement) Arabidopsis plants grown under both standard (90mE/m2/s) and high light (900mE/m2/s) conditions. We have compared the gene expression data obtained to that of the hpt mutant of arabidopsis which is lacking the homogentisate phytyltransferase enzyme, and is also tocopherol minus with an apparently normal phenotype under standard growth conditions. Gene Expression results showed large changes in expression profiles between plants grown under normal light and high light. In contrast, only small changes in gene expression were seen between the wild type and vte1 plants. The metabolic profiling data conformed these conclusions, again showing only small differences between the mutant and wild type plants grown under normal growth conditions, and showing much more dramatic differences in metabolites beween plants grown under normal and high light conditions.