Multigenska karakterizacija izolata bakterije 'Candidatus Phytoplasma asteris' iz uljane repice (Brassica napus ssp. oleifera (DC.) Metzg.)

master's thesis

• Title (english): Multigene characterization of ''Candidatus Phytoplasma asteris' isolate from oilseed rape (Brassica napus ssp. oleifera (DC.) Metzg.)
• Author: Biljana Glumac
• Mentor: Martina Šeruga Musić (mentor)
• Committee member: Martina Šeruga Musić (predsjednik povjerenstva)
• Committee member: Vesna Petrović-Peroković (član povjerenstva)
• Committee member: Ines Radanović (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2019, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology

Abstract

Fitoplazme (rod 'Candidatus Phytoplasma') su bakterije bez stanične stijenke koje parazitiraju u floemu biljaka i stanicama kukaca te ih nije moguće uzgajati u čistoj kulturi in vitro. Fitoplazme imaju iznimno reducirane genome (680 - 1600 kb) i nedostaju im mnogi esencijalni geni za različite metaboličke putove. U svom životnom ciklusu obavezno izmjenjuju dva domaćina – biljku i kukca koji je ujedno i vektor. Dok kod kukaca najčešće ne izazivaju nikakve smetnje, njihov učinak na biljke je često vrlo štetan. U biljkama se zadržavaju unutar floema što im osigurava unos potrebnih metabolita za preživljavanje i umnažanje. Bolesti proliferacije uljane repice često se povezuju se s infekcijom unutarstaničnim fitogenim bakterijama roda 'Candidatus Phytoplasma'. Budući da ove bakterije nije moguće uzgojiti u čistoj kulturi in vitro, dokaz prisutnosti bazira se isključivo na molekularnim metodama. Stoga je cilj ovog diplomskog rada bila identifikacija te multigenskaa tipizacija izolata fitoplazme 'Ca. P. asteris' dobivenih iz simptomatičnih uzoraka uljane repice prikupljenih u Zagrebu na eksperimentalnom zemjištu Agronomskog fakulteta. Zarazu fitoplazmatskom vrstom 'Ca. P. asteris' dokazala sam PCR/RFLP analizom gena za 16S rRNA, a filogenetska analiza fitoplazmatskog gena za 16S rDNA iz izolata simptomatične uljane repice potvrdila je rezultate PCR/RFLP klasifikacije te pripadnost vrsti 'Ca. P. asteris' kao i u prethodno identificiranim fitoplazmama na istom domaćinu. Analiza još tri genska lokusa izvan 16S rRNA gena nije samo potvrdila pripadnost podskupini I-B ribosomske skupine Aster Yellows i vrsti 'Ca. P. asteris', nego je po prvi puta pružila i detaljnu molekularnu karakterizaciju nekog izolata fitoplazme iz uljane repice.

Abstract (english)

Phytoplasmas (genus 'Candidatus Phytoplasma') are bacterial pathogens that cause numerous diseases in plants. Because of their small size and lack of a cell wall they are affiliated to the class Mollicutes. Phytoplasmas have extremely reduced genomes (680 - 1600 kb) and lack many essential genes for different metabolic pathways. Life cycle of phytoplasma involves two hosts – plants and insects. Although in insects they usually do not cause negative effects, their effect on plants is often harmful. In the infected plants phytoplasmas retain within phloem which ensures them to get required metabolites for growth and multiplication. Rapeseed proliferation diseases are often associated with infection with the intracellular phytopathogenic bacteria of the genus 'Candidatus Phytoplasma'. Since these bacteria cannot be grown in pure in vitro culture, detection and diagnosis are based mainly on molecular methods.Therefore, the aim of this study was the identification and multigene typing of 'Ca. P. asteris' phytoplasma obtained from symptomatic oilseed rape samples collected in Zagreb on the experimental plot of the Faculty of Agriculture. The infection with the ‘Ca. P. asteris' phytoplasma species was detected by PCR/RFLP gene analysis of 16S rRNA. Phylogenetic analysis of the phytoplasma 16S rDNA gene from isolates of symptomatic oilseed rape confirmed the results of PCR/RFLP classification and affiliation to the 'Ca. P. asteris' species, as in the previously identified phytoplasma isolates from the same host. The analysis of three more genetic loci outside the 16S didn't only confirm belonging to the subgroup I-B of the Aster Yellows group and 'Ca. P. asteris' species, but also provided detailed molecular characterization of an oilseed rape phytoplasma isolate for the first time.

• Keywords: fitoplazma; uljana repica; 16S rRNA; filogenetska analiza
• Keywords (english): physoplasm; rapeseed; 16S rRNA; phylogenetic analysis
• Language: croatian
• URN:NBN: urn:nbn:hr:217:945079
• Study programme: Title: Biology and Chemistry; Study programme type: university; Study level: graduate; Academic / professional title: profesor biologije i kemije (profesor biologije i kemije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2019-11-29 10:20:16