Biokemijski i molekularni odgovori uročnjaka (Arabidopsis thaliana) na kratkotrajni toplinski šok

master's thesis

• Title (english): Biochemical and molecular responses of thale cress (Arabidopsis thaliana) to short-term heat shock
• Author: Davor Merkaš
• Mentor: Željka Vidaković-Cifrek (mentor)
• Mentor: Sandra Vitko (komentor)
• Committee member: Željka Vidaković-Cifrek (predsjednik povjerenstva)
• Committee member: Biljana Balen (član povjerenstva)
• Committee member: Josip Skejo (član povjerenstva)
• Committee member: Tomislav Ivanković (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2025-02-04, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology

Abstract

Toplinski stres smatra se jednim od glavnih abiotičkih faktora koji negativno utječu na rast i razvoj biljaka. Cilj ovog rada bio je istražiti biokemijski i molekularni odgovor klijanaca uročnjaka (Arabidopsis thaliana) na toplinski šok određivanjem sadržaja H2O2, stupnja lipidne peroksidacije, fotosintetske učinkovitosti, količine enzima RuBisCO, indukcije proteina toplinskog šoka HSP90 i ekspresije nekoliko gena uključenih u odgovor na toplinski stres. Uzorci su analizirani odmah nakon izlaganja klijanaca temperaturi od 45 °C u trajanju 45 minuta te nakon oporavka u ukupnom trajanju 11 sati i 15 minuta. Rezultati su pokazali da neposredno nakon tretmana, a niti nakon oporavka, nije došlo do značajnog porasta količine H2O2 i stupnja lipidne peroksidacije, tj. na temelju spomenutih parametara nije potvrđen oksidacijski stres. Fotosintetska učinkovitost bila je smanjena, uz povećano rasipanje energije, što sugerira oštećenje fotosustava II (PSII). Primijenjeni tretman nije djelovao na količinu enzima RuBisCO. Potvrđena je indukcija proteina HSP90 te pojačana ekspresija gena HSFA3 i DREB2A. Dobiveni rezultati potvrđuju da su klijanci uročnjaka pokazali biokemijske i molekularne promjene nakon izlaganja toplinskom šoku, pružajući osnovu za daljnje istraživanje koje bi se temeljilo na uzorkovanju u više vremenskih točaka nakon tretmana te mjerenju aktivnosti antioksidacijskih enzima i količine neenzimskih antioksidansa.

Abstract (english)

Heat stress is considered one of the most important abiotic factors that affect plant growth and development. The aim of this work was to investigate the biochemical and molecular responses of the Arabidopsis thaliana seedlings to heat shock by determining the content of H2O2, the level of lipid peroxidation, the photosynthetic efficiency, the amount of the enzyme RuBisCO, the induction of heat shock proteins HSP90 and the expression of several genes involved in the response to heat stress. Samples were analyzed immediately after a 45-minute heat treatment at 45 °C and after a recovery period of 11 hours and 15 minutes. The results showed no significant increase in the amount of H2O2 and lipid peroxidation, i.e. oxidative stress was not confirmed by the mentioned parameters. Photosynthetic efficiency was reduced, with increased energy dissipation, indicating damage of photosystem II (PSII). The amount of RuBisCO enzyme was not changed. Induction of HSP90 proteins and increased expression of HSFA3 and DREB2A genes were confirmed. The results obtained show biochemical and molecular changes in A.thaliana seedlings after heat shock exposure and provide a basis for further research based on sampling at multiple time points and measuring the activity of antioxidant enzymes and the content of non-enzymatic antioxidants.

• Keywords: DREB2A; fotosintetska učinkovitost; HSFA3; HSP90; lipidna peroksidacija; oksidacijski stres
• Keywords (english): DREB2A; HSFA3; HSP90; lipid peroxidation; oxidative stress; photosynthetic efficiency
• Language: croatian
• URN:NBN: urn:nbn:hr:217:951908
• Project: Number: IP-2022-10-7874; Title: Alternativno prekrajanje gena BPM2 kao mehanizam uspostave funkcionalne raznolikosti porodice proteina MATH-BTB u uročnjaku Arabidopsis thaliana; Title: Alternative splicing of BPM2 as a mechanism for establishing a functional diversity of MATH-BTB protein family in Arabidopsis thaliana; Acronym: SpliceFun; Leader: Nataša Bauer; Jurisdiction: Croatia; Funder: Hrvatska zaklada za znanost; Funding stream: Research Projects
• Study programme: Title: Experimental Biology-University graduate programme; Study programme type: university; Study level: graduate; Academic / professional title: sveučilišni/a magistar/magistra eksperimentalne biologije (sveučilišni/a magistar/magistra eksperimentalne biologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2025-02-27 12:08:00