diplomsko delo
Kaja Adamek (Author), Jana Murovec (Mentor)

Abstract

Klasičnemu žlahtnjenju za pridobivanje rastlin z novimi lastnostmi se je pridružila genska tehnologija, ki omogoča hiter vnos in izražanje točno določenih genov iz kateregakoli organizma v rastlinah. Trenutno ima največ transgenih rastlin vnesen genski material, ki omogoča odpornost na herbicide. V zadnjih letih se za razvoj rastlin, odpornih na herbicide, uporablja tudi tehnologija CRISPR/Cas9. Sistem CRISPR/Cas9 izvira iz naravnega imunskega sistema bakterije Streptococcus pyogenes, ki služi kot obramba pred virusi. Ko virus okuži bakterijo, vanjo izloči DNA, ki se vstavi v lokus CRISPR. Po transkripciji se na ponavljajoče predele CRISPR RNA vežeta tracrRNA in protein Cas9, kar je znak za endonukleazo Cas9, da razreže RNA na krajše segmente, ki služijo bakteriji kot spomin na pretekle okužbe z virusom, kar omogoča hitrejši odziv ob ponovni okužbi. Za namene preurejanja genomov raziskovalci izkoriščajo sistem CRISPR/Cas9 tako, da umetno pripravijo vodilno RNA, ki se prilega specifičnemu zaporedju DNA. Nukleaza Cas9 tvori kompleks z vodilno RNA, ki usmerja nukleazo do željenega zaporedja. S to tehnologijo so bili spremenjeni številni geni za odpornost na herbicide, med drugimi gen ALS, geni za ACCazo, EPSPS, GS in PSII. Zaradi naraščanja števila na herbicide odpornih plevelov pridelovalci množično potrebujejo nove rastline z odpornostjo na herbicide. Ta naloga bi bila težko izvedljiva v doglednem času, če bi uporabiljali klasično žlahtnenje, saj bi zaradi velikosti rastlinskih genomov (in pogosto poliploidiji) verjetnost želene klasične mutacije zelo nizka. V svoji diplomski nalogi bom opisala molekularne osnove odpornosti na herbicide in kratko povzela dosedanje gensko spremenjene rastline z odpornostjo na herbicide. Nato se bom osredotočila na mehanizem preurejanja genomov s CRISPR/Cas9.

Keywords

tehnologija DNA;odpornost na herbicide;CRISPR/Cas9;mehanizmi urejanja baz;

Data

Language: Slovenian
Year of publishing:
Typology: 2.11 - Undergraduate Thesis
Organization: UL BF - Biotechnical Faculty
Publisher: [K. Adamek]
UDC: 606:631.528:602.6:633/634(043.2)
COBISS: 68226563 Link will open in a new window
Views: 283
Downloads: 47
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Other data

Secondary language: English
Secondary title: Development of herbicide resistant plants with genome editing
Secondary abstract: Classic breeding of plants allows the creation of new varieties with altered characteristics. Gene technology has the same goal but allows fast insertion and expression of particular genes from any organism in plants. Currently, most transgene plants carry genes for herbicide resistance. In the past few years, CRISPR/Cas9 technology has also been used for development of herbicide-resistant plants. CRISPR/Cas9 originates from the natural immune system of the bacteria Streptococcus pyogenes. This bacteria uses this immune system as a defence against viruses. When a virion infects a bacterium, it releases it's DNA, which inserts into the bacterial CRISPR locus. After transcription, tracrRNA and nuclease Cas9 bind to the repeating segments of the CRISPR RNA. This is a signal for the Cas9 endonuclease to cut the RNA into shorter fragments, which then serve as bacterial memory of virus infection and allow a faster response against a new viral infection. In research, CRISPR/Cas9 is used to edit genomes. This is achieved by artificial synthesis of the guiding RNA that binds to a specific DNA sequence. Cas9 forms a complex with the guiding RNA, which guides the nuclease to the targeted sequence. This technology has already allowed the altering of numerous genes which encode for herbicide resistance. Among these genes are ALS, and genes for ACCase, EPSPS, GS, PSII. Due to the increasing nuber of herbicide-resistant weeds, farmers are in need of new plants with resistance against herbicides. This task would be difficult to achieve quickly with the use of classical breeding techniques due to large genomes and polyploidy of plants. Polyploidy results in each mutation contributing to a relatively low resistance. In my dissertation, I will decribe the molecular basics of herbicide resistance and summarise herbicide resistant plants that have been created to this day. Finally, I will focus on the mechanisms of CRISPR/Cas9.
Secondary keywords: DNA technology;herbicide resistance;base editing;
Type (COBISS): Bachelor thesis/paper
Study programme: 0
Thesis comment: Univ. v Ljubljani, Biotehniška fak., Študij biotehnologije
Pages: VIII, 21 str.
ID: 13069928