Transformation of Madagascar periwinkle (Catharanthus roseus) for studying infection with ʼCandidatus Phytoplasma solaniʼ and enzymatic activities in infected plantsAnžič, Barbara (Avtor) Dermastia, Marina (Mentor) Roitsch, Thomas (Komentor) phytoplasmas‘Candidatus Phytoplasma solani'bois noirVitis viniferaCatharanthus roseusNicotiana benthamianaplant transformationenzymatic activityeffector proteins'Candidatus Phytoplasma solani' is an intracellular plant pathogenic bacterium that lives in phloem tissues and is transmitted from plant to plant by insects through ingestion of the infected phloem sap. This phytoplasma can cause various diseases of important crop plants, presumably through effectors. Previous studies have indicated that phytoplasma infections affect the metabolism of host plant carbohydrates and phenolic compounds, which can be associated with reactive oxygen species and antioxidant enzymes. As it is still not possible to routinely cultivate phytoplasmas under in-vitro conditions, we use phytoplasma-infected Catharanthus roseus as the model plant for this research. In this thesis, we attempted to establish a protocol for stable transformation of C. roseus, and tried to transform this with constructs of six effectors of ‘Ca. P. solani’, which were discovered through bioinformatics tools. In the second part of this thesis, the activities of the key enzymes involved in carbohydrate and antioxidant metabolism were assayed in: (i) grapevine leaf samples from a vineyard naturally infected with ‘Ca. P. solani’; (ii) leaf samples of greenhouse grown C. roseus infected with two different strains of ‘Ca. P. solani’; and (iii) leaf samples of Nicotiana benthamiana after transient transformation with the ‘Ca. P. solani’ effector constructs. The results confirm our hypothesis that infection with ‘Ca. P. solani’ significantly affects carbohydrate metabolism. However, the influence of infection was less obvious for antioxidant metabolism. [B. Anžič]20192019-10-06 07:45:03Magistrsko delo/naloga111641sl