Uloga sekoiridoidnih glukozida i beta-glukozidaze u odbrambenom odgovoru kičice (Centaurium erythraea Rafn) na stres povređivanjem
The role of secoiridoid glucosides and beta-glucosidase in common centaury (Centaurium erythraea Rafn) defense response to wounding
Abstract:
Centaurium erythraea Rafn (centaury) is a rich source of pharmaceutically active specialized metabolites including phenolic acids, flavonoids and especially secoiridoids. Secoiridoid glucosides are monoterpenoids based on a cyclopentan-C-pyran skeleton with the β-D glucose linked at C1 position. These compounds are subjected to hydrolysis catalyzed by enzymes β-glucosidases, and resulting aglycones could be subsequently directed towards different metabolic pathways in plants. Coordinated metabolic processes, such as biosynthesis and catabolism of secoiridoid glucosides, ensure constitutive presence of these bitter taste compounds in plant tissue, which play a decisive role in the defense against pathogens and herbivores. Pronounced accumulation of secoiridoids in centaury leaves observed during the response of plants to mechanical wounding was preceeded by the strong induction of the majority of biosynthetic genes as well as by the down-regulation of β-glucosidase, which catalyses the first step of secoiridoid glucosides catabolism. The expression of secoiridoids biosynthetic genes during response to wounding appears to be coordinately up-regulated and controlled at the transcriptional level, through the jasmonate signalling pathway. Two centaury β-glucosidases (CeBGLU1 and CeBGLU2), showing high substrate specificity for secoiridoid glucosides, were identified. Hydrolytic function of the two enzymes was confirmed by heterologous expression of candidate genes in the host organism (Escherichia coli), purification of recombinant proteins, and in vitro enzymatic assays. The results of the doctoral dissertation provide the basis for the further application of metabolic
Keywords:
Centaurium erythraea; Secoiridoid glucosides; β-glucosidase; Mechanical wounding; Gene expression; Functional characterization of genesSource:
University of Belgrade, Faculty of Biology, 2020, 1-133Funding / projects:
- Physiological, chemical and molecular analysis of the diversity of selected rare and endangered plant species and application of biotechnology for ex situ conservation and production of biologically active compounds (RS-MESTD-Basic Research (BR or ON)-173024)