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- Title
Functional interplay between glutathione and hydrogen sulfide in regulation of thiol cascade during arsenate tolerance of common bean ( Phaseolus vulgaris L.) genotypes.
- Authors
Talukdar, Dibyendu
- Abstract
Changes in expressions of up- and downstream thiol cascade were studied in leaves of Phaseolus vulgaris L. cv. VL-63 and its mutant, pvsod1 (deficient in superoxide dismutase activity) under 50 μM sodium arsenate (As), As + l-buthionine-sulfoximine (BSO) and As + BSO + Sodium hydrosulfide (NaHS)-treatments for 10 days. Main objective was to investigate the functional relationship between hydrogen sulfide (HS) and glutathione (GSH) in regulation of sulfate transporters and cysteine metabolisms as up-stream thiol components and GSH, phytochelatins (PCs) and antioxidant defense response as downstream cascade under As-exposure. As treatment alone initiated coordinated inductions of sulfate transport, biosynthesis of cysteine, GSH, and PCs, and GSH-mediated antioxidant defense in the pvsod1 mutant. At As + BSO, GSH synthesis was blocked, resulting in significantly low GSH redox pool and steep decline in GSH-dependent antioxidant capacity of both the genotypes. However, unlike VL-63, cysteine-degradation pathway was induced in pvsod1 mutant, resulting in significant accumulation of endogenous HS. The HS-surge in the pvsod1 mutant stimulated ascorbate-dependent antioxidant defense and catalases and regulated O-acetylserine (thiol)lyase activity, preventing overaccumulation of HO and free cysteine, respectively. No As-induced oxidative stress symptom was observed in the mutant. This trend was maintained at As + BSO + NaHS treatment, also. In contrast, failure to induce entire cascade from sulfate transport to downstream antioxidant defense led to onset of As-induced oxidative damage in VL-63 plant. Results revealed dual roles of HS as (a) stimulator of GSH-independent antioxidant defense and (b) regulator of cysteine homeostasis through its metabolic diversion during As-exposure and blockage of GSH biosynthesis.
- Publication
3 Biotech, 2015, Vol 5, Issue 5, p819
- ISSN
2190-572X
- Publication type
Article
- DOI
10.1007/s13205-015-0285-6