Profiles of Antioxidant Isoenzymes in the Pathosystem Scenedesmus–phlyctidium after Treatment with Plant Growth Regulators

The present study was undertaken to investigate the possibilities of some plant growth regulators – abscisic acid, fluridone, methyl jasmonate, salicylic acid and the cytokinin 4-PU-30 to participate in the disease tolerance induction in the unicellular green alga Scenedesmus incrassatulus invaded with the unicellular fungal parasite Phlyctidium scenedesmi. We established that protein profiles in host cells changed drastically after the parasite invasion. Pretreatment of algal cells with PGR (4-PU-30 and MeJA) depressed the depletion of soluble proteins in Scenedesmus cells caused by Phlyctidium invasion. The presence of SA and MeJA in the cultivation medium caused a significant enhancement of the amount of the fastest moving thermostable protein band. In ABA-, fluridoneand 4-PU-30-pretreated invaded algal cells significant activation of peroxidase which plays an important role in resistance induction was observed. SA stopped catalase enhancement in the invaded cells. Parasite invasion was connected with both qualitative and quantitative changes in the spectrum of SOD. The data obtained support the suggestion that ABA, MeJA, 4-PU-30 and SA are involved in plant-pathogen interactions and acquisition of pathogen tolerance.