title: Thiamin confers enhanced tolerance to oxidative stress in Arabidopsis.
abstract: Thiamin and thiamin pyrophosphate (TPP) are well known for their important roles in human nutrition and enzyme catalysis. In this work, we present new evidence for an additional role of these compounds in the protection of cells against oxidative damage. Arabidopsis (Arabidopsis thaliana) plants subjected to abiotic stress conditions, such as high light, cold, osmotic, salinity, and oxidative treatments, accumulated thiamin and TPP. Moreover, the accumulation of these compounds in plants subjected to oxidative stress was accompanied by enhanced expression of transcripts encoding thiamin biosynthetic enzymes. When supplemented with exogenous thiamin, wild-type plants displayed enhanced tolerance to oxidative stress induced by paraquat. Thiamin application was also found to protect the reactive oxygen species-sensitive ascorbate peroxidase1 mutant from oxidative stress. Thiamin-induced tolerance to oxidative stress was accompanied by decreased production of reactive oxygen species in plants, as evidenced from decreased protein carbonylation and hydrogen peroxide accumulation. Because thiamin could protect the salicylic acid induction-deficient1 mutant against oxidative stress, thiamin-induced oxidative protection is likely independent of salicylic acid signaling or accumulation. Taken together, our studies suggest that thiamin and TPP function as important stress-response molecules that alleviate oxidative stress during different abiotic stress conditions.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada 89557, USA.
authors.forename: Meral
authors.initials: M
authors.lastname: Tunc-Ozdemir
authors.forename: Gad
authors.initials: G
authors.lastname: Miller
authors.forename: Luhua
authors.initials: L
authors.lastname: Song
authors.forename: James
authors.initials: J
authors.lastname: Kim
authors.forename: Ahmet
authors.initials: A
authors.lastname: Sodek
authors.forename: Shai
authors.initials: S
authors.lastname: Koussevitzky
authors.forename: Amarendra Narayan
authors.initials: AN
authors.lastname: Misra
authors.forename: Ron
authors.initials: R
authors.lastname: Mittler
authors.forename: David
authors.initials: D
authors.lastname: Shintani
mesh_terms: D017360:Arabidopsis / Q000187:drug effects* / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000502:physiology; D009154:Mutation; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000502:physiology*; D017382:Reactive Oxygen Species; D020156:Salicylic Acid / Q000378:metabolism; D036226:Seedlings / Q000502:physiology; D013831:Thiamine / Q000494:pharmacology*
chemical_list: D029681:Arabidopsis Proteins; D017382:Reactive Oxygen Species; D020156:Salicylic Acid; D013831:Thiamine