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Comparative analysis of peroxiredoxin activation in the brown macroalgae Scytosiphon gracilis and Lessonia nigrescens (Phaeophyceae) under copper stress
Author(s) -
Lovazzano Carlos,
Serrano Carolina,
Correa Juan A.,
ContrerasPorcia Loretto
Publication year - 2013
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/ppl.12047
Subject(s) - peroxiredoxin , copper , biology , catalase , peroxidase , botany , reactive oxygen species , oxidative stress , superoxide dismutase , western blot , biochemistry , microbiology and biotechnology , enzyme , chemistry , organic chemistry , gene
Among thiol‐dependent peroxidases ( TDPs ) peroxiredoxins ( PRXs ) standout, since they are enzymes capable of reducing hydrogen peroxide, alkylhydroperoxides and peroxynitrite, and have been detected in a proteomic study of the copper‐tolerant species Scytosiphon gracilis . In order to determine the importance of these enzymes in copper‐stress tolerance, TDP activity and type II peroxiredoxin ( II PRX ) protein expression were compared between the opportunistic S. gracilis and the brown kelp Lessonia nigrescens , a species absent from copper‐impacted sites due to insufficient copper‐tolerance mechanisms. Individuals of both species were cultured with increasing copper concentrations (0–300 µg l −1 Cu) for 96 h and TDP activity and lipoperoxides ( LPXs ) were determined together with II PRX expression by immunofluorescence and Western blot analysis. The results showed that TDP activity was higher in S. gracilis than L. nigrescens in all copper concentrations, independent of the reducing agent used (dithiothreitol, thioredoxin or glutaredoxin). This activity was copper inhibited in L. nigrescens at lower copper concentrations (20 µg l −1 Cu) compared to S. gracilis (100 µg l −1 Cu). The loss of activity coincided in both species with an increase in LPX , which suggests that TDP may control LPX production. Moreover, II PRX protein levels increased under copper stress only in S. gracilis . These results suggest that in S. gracilis TDP , particularly type II peroxiredoxin ( II PRX) , acts as an active antioxidant barrier attenuating the LPX levels generated by copper, which is not the case in L. nigrescens . Thus, from an ecological point of view these results help explaining the inability of L. nigrescens to flourish in copper‐enriched environments.