Specific Roles of α- and γ-Tocopherol in Abiotic Stress Responses of Transgenic Tobacco

摘要: Tocopherols are lipophilic antioxidants that synthesized exclusively in photosynthetic organisms. In most higher plants, α- and γ-tocopherol predominant with their ratio being under spatial temporal control. While α-tocopherol accumulates predominantly tissue, seeds rich γ-tocopherol. To date, little is known about the specific roles of different plant tissues. study impact tocopherol composition content on stress tolerance, transgenic tobacco (Nicotiana tabacum) plants constitutively silenced for homogentisate phytyltransferase (HPT) methyltransferase (γ-TMT) activity were created. Silencing HPT lead to an up 98% reduction total accumulation compared wild type. Knockdown γ-TMT resulted 95% leaves transgenics, which was almost quantitatively compensated by increase The response transgenics salt sorbitol methyl viologen treatments comparison type studied. Each condition imposes oxidative along additional challenges like perturbing ion homeostasis, desiccation, or disturbing photochemistry, respectively. Decreased increased sensitivity HPT:RNAi toward all tested conditions, whereas γ-TMT-silenced showed improved performance when challenged viologen. However, tolerance strongly decreased. Membrane damage reduced after viologen-mediated stress, as evident less lipid peroxidation and/or electrolyte leakage. Therefore, our results suggest vivo.