Karakterizacija fenilpropanoidnog biosintetskog puta u mutantima lana metodom metabolomičkog pristupa

master's thesis

• Title (english): Characterization of flax mutants for the phenylpropanoid biosynthetic pathway using a metabolomic approach
• Author: Daniel Valić
• Mentor: Vladimir Mrša (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Chemistry and Biochemistry); (Laboratory for Biochemistry); Zagreb
• Defense date and country: 2015-07-02, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Fenilpropanoidni biosintetski put je jedan od najvažinijih biosintetskih puteva sekundarnih metabolita u biljaka. Iako su istraživani već mnogo godina, uloga fenilpropanoidnih spojeva u biljaka još uvijek nije u potpunosti razjašnjena. Lignani su jedni od najinteresantnijih spojeva fenilpropanoidnog biosintetskog puta jer pokazuju antioksidativna, bakteriostatska i fitoestrogenska svojstva, kao i svojstva prevencije hormonski-ovisnih malignih oboljenja. U ovom istraživanju korišteni su mutanti lana s karakteristikom utišane ekspresije gena za enzim pinoresinol-lariciresinol reduktazu 1 (PLR 1) mehanizmom RNA interferencije. PLR 1 je enzim odgovoran za akumulaciju (+)-sekoisolariciresinol diglukozida ((+)-SDG), glavnog lignana u lanu. Korištene analitičke metode su NMR i LC-MS. Linije PLR 1 mutanata pokazale su značajnu razliku u sastavu 19 metabolita. Gubitak funkcije PLR 1 enzima dovodi do velikih promjena u sekundarnom metabolizmu (lignanima, fenolnim kiselinama i cijanogenim glikozidima) kao i u primarnom metabolizmu (aminokiselinama i šećeru rafinozi). Kao posljedica, primijećen je značajan pad sposobnosti akumulacije (+)-SDG,
umjesto kojeg su se u makromolekulu lignana ugradili glukozilirani oblici lariciresinola i pinoresinola. Metabolički fluks lignana u analiziranim mutantima preusmjeren je prema enzimu PLR 2.

Abstract (english)

The phenylpropanoid biosynthetic pathway represents one of the most important secondary metabolite biosynthetic pathways in plants. Although being investigated for many years, the role and regulation of many phenylpropanoids in planta remains unknown. This is notably the case with lignans, whose beneficial health effects are recognized in terms of antioxidant, bacteriostatic, phytoestrogenic and cancer chemoprotective effects. In order to get a better insight into the biosynthesis of phenylpropanoids, RNAi mediated pinoresinol-lariciresinol reductase 1 (PLR 1) mutants were characterized using a metabolomic approach. PLR 1 is the enzyme responsible for the biosynthesis of the main lignan in flax (+)-secoisolariciresinol diglucoside ((+)-SDG). The used analytical techniques were NMR and LC-MS. The mutant lines have shown a significantly different composition regarding 19 metabolites. It has been observed that the loss of PLR 1 function significantly affected the content of secondary metabolites (lignans, phenolic acids and cyanogenic glycosides) but primary metabolites as well (amino acids and raffinose). A drastic decrease in the (+)-SDG content was observed as well as an increase in the contents of glucosilated forms of lariciresinol and pinoresinol. The PLR 1 mutants showed the loss of ability to accumulate the lignan (+)-SDG instead of which they incorporate the glucosilated forms of lariciresinol and pinoresinol in the lignan macromolecule. The observed effects may correspond to a redirection of lignan flux via PLR 2, an enzyme already characterized in flax seed, and/or support the hypothesis of the presence of PLR 3, on which some indications have recently been reported.

• Keywords: metabolomika; fenilpropanoidni put; lignani; SDG; Linum usitatissimum
• Keywords (english): metabolomics; phenylpropanoid pathway; lignans; SDG; Linum usitatissimum
• Language: english
• URN:NBN: urn:nbn:hr:159:018580
• Study programme: Title: Molecular Biotechnology; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka molekularne biotehnologije (magistar/magistra inženjer/inženjerka molekularne biotehnologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2017-05-02 12:29:51