Premium
Sulfite oxidase controls sulfur metabolism under SO 2 exposure in Arabidopsis thaliana
Author(s) -
RANDEWIG DÖRTE,
HAMISCH DOMENICA,
HERSCHBACH CORNELIA,
EIBLMEIER MONIKA,
GEHL CHRISTIAN,
JURGELEIT JENS,
SKERRA JESSICA,
MENDEL RALF R.,
RENNENBERG HEINZ,
HÄNSCH ROBERT
Publication year - 2012
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.2011.02420.x
Subject(s) - sulfite , sulfur metabolism , sulfite reductase , sulfur , chemistry , sulfite oxidase , metabolism , sulfate , biochemistry , arabidopsis thaliana , sulfur dioxide , detoxification (alternative medicine) , cysteine , glutathione , mutant , reductase , inorganic chemistry , enzyme , organic chemistry , gene , pathology , medicine , alternative medicine
In the present study, the significance of sulfite oxidase (SO) for sulfite detoxification and sulfur assimilation was investigated. In response to sulfur dioxide (SO 2 ) exposure, a remarkable expansion of sulfate and a significant increase of GSH pool were observed in wild‐type and SO‐overexpressing Arabidopsis . These metabolic changes were connected with a negative feedback inhibition of adenosine 5′‐phosphosulfate reductase (APR), but no alterations in gas exchange parameters or visible symptoms of injury. However, Arabidopsis SO‐KO mutants were consistently negatively affected upon 600 nL L −1 SO 2 exposure for 60 h and showed phenotypical symptoms of injury with small necrotic spots on the leaves. The mean was reduced by about 60% over the fumigation period, accompanied by a reduction of net CO 2 assimilation and SO 2 uptake of about 50 and 35%. Moreover, sulfur metabolism was completely distorted. Whereas sulfate pool was kept constant, thiol‐levels strongly increased. This demonstrates that SO should be the only protagonist for back‐oxidizing and detoxification of sulfite. Based on these results, it is suggested that co‐regulation of SO and APR controls sulfate assimilation pathway and stabilizes sulfite distribution into organic sulfur compounds. In conclusion, a sulfate–sulfite cycle driven by APR and SO can be postulated for fine‐tuning of sulfur distribution that is additionally used for sulfite detoxification, when plants are exposed to atmospheric SO 2 .