engleski

Response of Kalanchoe daigremontiana to wounding and infection with Agrobacterium tumefaciens

Background and Purpose: Transformation of plant tissue with Agrobacterium tumefaciens includes wounding of plant and subsequent infection by bacteria. Polyphenol oxidase activity and oxidative stress parameters – the content of H2O2, as well as activity and isoenzymes of antioxidative enzymes catalase, pyrogallol and guaiacol peroxidase were investigated as markers of plant response to wounding and infection. Materials and Methods: Five tissue types – healthy tissue, wounded tissue, tissue in immediate proximity of the wound, tumour tissue and tissue next to the tumourwere collected on 7th, 14th and 21st day afterwounding or infection. Activities of antioxidative enzymes were evaluated spectrophotometrically. Isoenzymes were separated electrophoretically in native conditions. H2O2 content was estimated by measuring the titanium hydro- -peroxide complex. Results and Conclusion: All measured parameters were remarkably different in tumour in comparison to healthy tissue. Activities of peroxidases were significantly increased, accompanied with induction of new isoenzymes. After two weeks of the experiment catalase activity was also significantly increased in tumour tissue as well as in tissue next to the wound. H2O2 content was lower in tumour after three weeks. Aside from tumour tissue, polyphenol oxidase activity was significantly increased in tissue next to the tumour. Remarkably increased peroxidase and polyphenol oxidase activity in tumour tissue, additional isoenzymes of peroxidases as well as decreased H2O2 content, indicated changes in tissue organisation and induction of defence mechanisms against pathogen, in which these two groups of enzymes are involved.Wounded tissue, as well as tissue next to the wound or infection, did not show significant variation from healthy tissue.

Kalanchoe daigremontiana; Agrobacterium tumefaciens infection; antioxidative enzymes; H2O2 content

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