Plastid Alternative Oxidase (PTOX) Promotes Oxidative Stress When Overexpressed in Tobacco

• DOI: 10.1074/jbc.m109.021667
• Publication Date: 2009-09-10T00:12:51Z
• Authors: Eiri Heyno; Christine M. Gross; Constance Laureau; Marcel Culcasi; Sylvia Pietri; Anja Krieger-Liszkay
• Keywords: Photoinhibition; Wild type; Alternative oxidase

Photoinhibition and production of reactive oxygen species were studied in tobacco plants overexpressing the plastid terminal oxidase (PTOX). In high light, these was more susceptible to photoinhibition than wild-type plants. Also oxygen-evolving activity isolated thylakoid membranes from PTOX-overexpressing strongly inhibited light thylakoids contrast low PTOX overexpressor, protected against while wild type they significantly damaged. The superoxide hydroxyl radicals shown by EPR spin-trapping techniques different samples. Superoxide radical stimulated overexpressor. Two-thirds maintained presence DNP-INT, an inhibitor cytochrome b(6)f complex. No increase SOD content observed overexpressor compared with type. We propose that is produced a side reaction can only act as safety valve under stress conditions when generated detoxified efficient antioxidant system.