Impact of cyclopentenone-oxylipins on the proteome of Arabidopsis thaliana.

Both enzymatically and non-enzymatically generated oxylipins fulfill signalling functions in plant responses to biotic and oxidative stress on the cellular level. We studied the impact of two different exogenously applied cyclopentenone-oxylipins on the proteome of Arabidopsis thaliana leaves: the enzymatically formed 12-oxo-phytodienoic-acid, a member of the jasmonate family of mediators, and A(1)-phytoprostane generated by a free-radical mechanism upon biotic and oxidative stress. Infiltration of leaves with these oxylipins led to induction of classical stress proteins like chaperones as well as enzymes connected to the cellular redox and detoxification systems.

General detoxification and stress responses are mediated by oxidized lipids through TGA transcription factors in Arabidopsis.

12-oxo-phytodienoic acid and several phytoprostanes are cyclopentenone oxylipins that are formed via the enzymatic jasmonate pathway and a nonenzymatic, free radical-catalyzed pathway, respectively. Both types of cyclopentenone oxylipins induce the expression of genes related to detoxification, stress responses, and secondary metabolism, a profile clearly distinct from that of the cyclopentanone jasmonic acid. Microarray analyses revealed that 60% of the induction by phytoprostanes and 30% of the induction by 12-oxo-phytodienoic acid was dependent on the TGA transcription factors TGA2, TGA5, and TGA6.

Modified nicotine metabolism in transgenic tobacco plants expressing the human cytochrome P450 2A6 cDNA.

In this study, the human cytochrome P450 (CYP) 2A6 was used in order to modify the alkaloid production of tobacco plants. The cDNA for human CYP2A6 was placed under the control of the constitutive 35S promoter and transferred into Nicotiana tabacum via Agrobacterium-mediated transformation. Transgenic plants showed formation of the recombinant CYP2A6 enzyme but no obvious phenotypic changes.