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.

Arbuscular Mycorrhizal Fungi Improve the Antioxidative Response and the Seed Production of Suaedoideae Species Suaeda physophora Pall Under Salt Stress

“…Several studies found that there is a strong correlation between the enzymatic antioxidant defence system and the salt tolerance of plants (Misra et al, 2006;Tunc-Ozdemir et al, 2009). The present study found that the POD and SOD activities increased with an increase in the salt concentration.…”

The endoplasmic reticulum-associated degradation is necessary for plant salt tolerance

“…This result indicates that HRD3A is at least important for removing the source of ROS production in plant cells, and perhaps this is the reason why the hrd3a plants showed arrested growth and died more quickly under the salt treatment condition. The chemical paraquat, an inducer of oxidative stress, can induce cell death in both plants and animals [40,41]. To determine whether paraquat can be more harmful to hrd3a mutant plants, hrd3a-1, hrd3a-2, and WT seeds were plated and grown on MS medium containing 0.2 µM paraquat.…”

Nitric oxide ameliorates stress responses in plants

“…As a signaling molecule, NO is believed to be one of the first antioxidants during early evolution which can up-regulate antioxidants (Beligni and Lamattina 2002) and indirectly mediate H 2 O 2 level in the cascade of events leading to alterations of antioxidant gene expression (Leshem 1996). A great variety of abiotic stresses including drought, salinity, ultraviolet light, air pollutants and heavy metals cause damage to plants, either directly or indirectly through reactive oxygen species (ROS) formation (Tunc-Ozdemir et al 2009), such as superoxide anion (O 2 -) and hydroxyl (OH) radicals, hydrogen peroxide (H 2 O 2 ), and singlet oxygen ( 1 O 2 ). Two mechanisms are proposed by which NO might abate oxidative stress.…”