Mechanisms of the Selenium Tolerance of theArabidopsis thalianaKnockout Mutant of Sulfate Transporter SULTR1;2

Abstract

We investigated the mechanism of selenium (Se) tolerance using an Arabidopsis thaliana knockout mutant of a sulfate transporter, sultr1;2. Se stress inhibited plant growth, decreased chlorophyll contents, and increased protein oxidation and lipid peroxidation in the wild type, whereas the sultr1;2 mutation mitigated damage of these forms, indicating that sultr1;2 is more tolerant of Se than the wild type is. The accumulation of symplastic Se was suppressed in sultr1;2 as compared to the wild type, and the chemical speciation of Se in the mutant was different from that in the wild type. Regardless of Se stress, the activities of ascorbate peroxidase, catalase, and peroxidase in the mutant were higher than in the wild type, while the activity of superoxide dismutase in the mutant was the same as in the wild type. These results suggest that the sultr1;2 mutation confers Se tolerance on Arabidopsis by decreasing symplastic Se and maintaining antioxidant enzyme activities.

Enhanced Iron and Selenium Uptake in Plants by Volatile Emissions of Bacillus amyloliquefaciens (BF06)

“…The low-affinity sulfate transporters AtSULTR2;1 and AtSULTR2;2 have also been found to catalyze Se uptake into the stele cells, and the activity of AtSULTR2;1 can be positively regulated by the AtSULTR3;5 that does not directly catalyze Se transport [72]. Additionally, increased Se availability can induce the expression of SULTR2;1 and SULTR2;2 in Arabidopsis [60,73,74]. Intriguingly, the transcription levels of SULRT2 are greater in the roots of Se hyperaccumulator species than non-Se hyperaccumulator species, indicating that high-level expression of SULRT2 contributed to the increased Se flux from roots to shoots in the hyperaccumulator species [75].…”

Nitro-oxidative stress contributes to selenite toxicity in pea (Pisum sativum L)

“…At the whole plant level, the characteristic symptoms of Se toxicity are, necrosis, withering and drying of leaves chlorosis (Mengel and Kirkby 1987), reduced photosynthetic activity and premature death (Tripathi and Misra 1974); however the toxic levels of Se for plants vary between species (Kaur et al 2014). Moreover, excess of selenium reduces shoot biomass by decreasing fresh weight, hypocotyl length and cotyledon diameter of Arabidopsis (Grant et al 2011;Ohno et al 2012;Lehotai et al 2011) and also affects the root system through the inhibition of primary root elongation (Grant et al 2011;Lehotai et al 2012). At cellular level, toxicity is partly caused by the alteration of protein synthesis, structure and function, as a result of the incorporation of Se in the amino acids, cysteine and methionine.…”

Influence of selenite and selenate on growth, leaf physiology and antioxidant defense system in wheat (Triticum aestivum L.)

“…In the present study, low levels of lipid peroxidation (LPO) in Se‐treated plants might be due to the activation of MDA degradation system due to lowered symplastic Se . The increased H 2 O 2 accumulation in Se treated plants may be due to non‐significant changes in GR and low APX activities during later stages of development.…”

“…54 In the present study, low levels of lipid peroxidation (LPO) in Se-treated plants might be due to the activation of MDA degradation system due to lowered symplastic Se. 55 The increased H 2 O 2 accumulation in Se treated plants may be due to non-significant changes in GR and low APX activities during later stages of development. Previous researchers 39,56 have reported positive correlation between Se contents in different plants species and increased activities of SOD, CAT and glutathione peroxidase enzymes.…”