engleski

Molecular mechanisms of transport and biological functions of phenolic derivatives in Arabidopsis thaliana (L.) Heynh

Phenolic derivatives have many important roles in plants, yet mechanisms of their transport and all biological activities are still not elucidated. In scope of this dissertation, the transport abilities and certain biological activities of two types of phenolic derivatives (selected flavonoids and salicylic acid) were investigated. For research purposes, spectrophotometric methods were used, fluorescence microscopy, gass chromatography coupled with mass spectrometry, high performance liquid chromatography, and quantitative real time polymerase chain reaction. It was found that the complexation of quercetin with europium improves the long distance transport ability of quercetin. The involvement of this complex in certain aspects of Arabidopsis pathological states was further tested. Satellite-associated Cucumber mosaic virus (CMVsat) double stranded RNAs were found to specifically interact with this complex by degrading it into free quercetin. It was observed that the complex could moderate symptom development in Plasmodiophora brassicae-infected Arabidopsis. Another flavonoid, kaempferol, was shown to be involved in Arabidopsis thaliana-CMVsat interaction. Intriguing, in scope of this dissertation it was found that some compounds from flavonoid biosynthetic pathway are needed for CMVsat accumulation in Arabidopsis. Regarding salicylic acid, it was found that in Arabidopsis infected with P. brassicae it is synthesized from chorismate, and long distance transported in methylated form (as methyl-salicylate). The quantitative PCR analysis revealed that the expression of gene for isochorismate synthase and the expression of gene for salicylic acid methyltransferase were induced upon infection with P. brassicae. In Arabidopsis infected with CMVsat, salicylic acid is also transported as methyl-salicylate, but the transport rate and accumulation of salicylic acid are quite different than in Arabidopsis infected with P. brassicae.

phenolic derivatives; flavonoids; salicylic acid; Arabidopsis thaliana; Plasmodiophora brassicae; satellite-associated Cucumber mosaic virus

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