Protein glutathionylation protects wheat (Triticum aestivum Var. Sonalika) against Fusarium induced oxidative stress.

Fusarium induced oxidative stress could be recovered by reversible protein oxidative modification through the process of glutathionylation in co-stressed (low-dose (50 μM) Cd ²⁺ pre-treatment followed by Fusarium inoculation) wheat seedlings. Co-stressed seedlings showed low disease severity index as compared to Fusarium infected seedlings. A reduced level of hydrogen peroxide (H ₂ O ₂ ) and carbonyl contents due to irreversible protein oxidation were observed in co-stressed seedlings as compared to Fusarium infected seedlings. Further, a comparative biochemical assay showed an enhanced glutathione content in co-stressed tissues as compared to Fusarium infected tissues. In an investigation, reduced glutathione pre-coated agarose gel beads were used to pull down proteins having affinity with GSH. Fructose-1, 6-bisphosphate aldolase and 3-Phosphoglycerate kinase were observed to be co-existed in co-stressed seedlings when analysed by LC-MS/MS after being processed through protein-pull assay. Co-stressed tissues showed an enhanced free protein thiol content as compared to Fusarium infected tissues. The ratio of free thiol to thiol disulfides was also observed to be increased in co-stressed tissues as compared to Fusarium infected tissues. In contrast, the quantitative assay by Ellman's reagent and qualitative analysis by diagonal gel electrophoresis showed enhanced protein thiol disulfides in Fusarium infected tissues as compared to co-stressed tissues. Further, glutaredoxin, responsible for the reverse reduction of proteins was observed to be enhanced in co-stressed tissues as compared to Fusarium infected tissues. Thus, a low dose Cd ²⁺ triggered glutathionylation is suggestive of offering tolerance against Fusarium induced oxidative stress and protects target proteins from irreversible modification and permanent damage in wheat.
(Copyright © 2016 Elsevier Masson SAS. All rights reserved.)