CHANGES IN PROTEIN SYNTHESIS AND IN SUPEROXIDE DISMUTASE ACTIVITY IN PHASEOLUS BEAN PLANTS UNDER OZONE STRESS

R. Bernardi, C. Nali, R. Gargiulo, C. Pugliesi, G. Lorenzini, M. Durante

Abstract


Protein synthesis and the activity of superoxide dismutases (SODs) were analyzed in bean plants (Phaseolus vulgaris L.) cv. ‘Groffy’ exposed to acute and chronic ozone (O3) fumigation. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) patterns of total soluble leaf proteins revealed the accumulation of a newly synthesised 33 kDa polypeptide following acute (150 nl l-1) and chronic (50 nl l-1 and 100 nl l-1) treatments and the disappearance of a 36 kDa polypeptide after three hours of recovery from the acute treatment. The control plants showed four distinct SOD isoforms with a relative mobility (Rf) of 0.45 (MnSOD), 0.59 (Cu/ZnSOD), 0.80 (Cu/ZnSOD), and 0.85 (unidentified). Acute O3 fumigation induced a rise of MnSOD activity while the levels of both Cu/ZnSOD isoenzymes remained almost unaltered. However, the activity of the more anodic Cu/ZnSOD isoform increased remarkably after three hours of recovery in clean air. Two additional SOD isoenzymes (Rf = 0.63 and 0.68), induced by chronic fumigation, reached highest values in plants treated with 100 nl l-1 of O3 for seven days. Under chronic conditions, MnSOD activity levels remained unaltered or fell with respect to control plants. By contrast, a rise of the activities of both Cu/ZnSOD isoforms was observed after fumigation protracted for two or four days. Nevertheless, after seven days of treatment, levels of both Cu/ZnSOD isoenzymes and of the more anodic (Rf = 0.85) SOD isoform decreased. Changes in the levels of distinct components of the SOD system depending on the level of O3 fumigation imposed suggest a specific function for each isoform in protecting plant cells from oxidative stress.

Keywords


air pollution; antioxidant systems; electrophoresis; oxidative stress; Phaseolus vulgaris

Full Text:

PDF


DOI: http://dx.doi.org/10.4454/jpp.v83i2.1117

Refbacks

  • There are currently no refbacks.


EDIZIONI ETS, Pisa, Italy