Otpornost autohtonih sojeva Bradyrhizobium japonicum na stres izazvan nedostatkom vlage

master's thesis

• Title (english): Resistance of indigenous Bradyrhizobium japonicum strains to water stress deficiency
• Author: Ana Puljko
• Mentor: Sanja Sikora (mentor)
• Committee member: Sanja Sikora (predsjednik povjerenstva)
• Committee member: Mihaela Blažinkov (član povjerenstva)
• Committee member: Snježana Kereša (član povjerenstva)
• Granter: University of Zagreb; Faculty of Agriculture; (Department of Microbiology); Zagreb
• Defense date and country: 2018-09-21, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Agronomy

Abstract

Biološka fiksacija dušika uvelike ovisi o uvjetima tla, a nedostatak vode uzrokuje porast koncentracije soli i povišenje osmotskog tlaka u tlu što negativno utječe na simbiozni odnos biljaka i bakterija te na samu fiksaciju dušika. U ovom diplomskom radu 15 autohtonih sojeva Bradyhrizobium japonicum izoliranih iz pet različitih područja Republike Hrvatske podvrgnuto je ispitivanjima u uvjetima in vitro suše i pri povišenom sadržaju soli. Izvršena je identifikacija sojeva ERIC-PCR metodom radi utvrđivanja genetske varijabilnosti autohtonih bakterija. Uvjeti in vitro nedostatka vode su se utvrđivali pomoću polietilen glikola (PEG) 6000 gdje je pri 15 % PEG 6000 autohtoni soj izoliran iz područja istočne Slavonije B. japonicum IS1 je tolerantan na nedostatak vode. Najmanje je otporan autohtoni soj B. japonicum ZS4, izoliran iz zapadne Slavonije. Pri koncentraciji PEG 6000 od 30 %, autohtoni soj istočne Slavonije, B. japonicum IS2 izrazito je otporan na osmotski stres, a najmanje tolerantan na nedostatak vode je soj B. japonicum IS4, izoliran s područja istočne Slavonije. Kod svih ispitivanih sojeva uočen je dobar rast pri koncentraciji od 1 % NaCl. Umjeren rast je utvrđen kod autohtonog soja iz područja Koprivnice i kod referentnog soja B. japonicum 344, dok dva soja zapadne Slavonije nisu tolerantna na 2 % NaCl. Dva autohtona soja Baranje, jedan soj Istre, tri soja istočne Slavonije i jedan soj iz Koprivnice su otporni na salinitet od 3 % NaCl. Autohtoni soj Baranje, Istre i dva iz istočne Slavonije su toleratni na izrazito visoke koncentracije od 4 % NaCl. Prema rezultatima ERIC-PCR metode utvrđeno je da genetska sličnost nije uvjetovana mjestu izolacije. Svi sojevi su podjeljeni u dvije glavne grupe s niskom relativnom sličnošću. Najveća genetska sličnost bila je utvrđena kod sojeva izoliranih iz područja Baranje, istočne Slavonije, Koprivnice i zapadne Slavonije.

Abstract (english)

Biological nitrogen fixation is largely dependant on soil conditions. Lack of water causes increased salt concentration and elevated osmotic pressure in the soil, which negatively affect the symbiotic relationship between plant and bacteria, and nitrogen fixation itself. In this master thesis, fifteen indigenous strains Bradyrhizobium japonicum isolated from five different regions of the Republic of Croatia were subjected to in vitro investigations in drought conditions and with increased concentrations of NaCl. Identification of strains was carried out with ERIC-PCR method in order to determine genetic variability of indigenous bacteria. Conditions of in vitro water deficiency were determined with polyethilene glycol (PEG) 6000. At 15 % of PEG 6000 indigenous strain isolated from east Slavonia region, B. japonicum IS1 is tolerant to the lack of water. Least resistant strain is B. japonicum ZS4, isolated from west Slavonia. At the concentraction of 30 % PEG 6000, indigenous strain from eastern Slavonia, B. japonicum IS2, is distincively resistant to osmotic pressure and least tolerant is strain B. japonicum IS4, from eastern Slavonia. In all tested strains, good growth is observed at the concentration of 1 % NaCl. Moderate growth is noticed in the indigenous strain from Koprivnica region and in the referent strain B. japonicum 344, whilst two strain from western Slavonia are intolerant at 2 % NaCl. Two indigenous strains of Baranja region, one from Istria, three from eastern Slavonia and one from Koprivnica region are resistant on the salinity of 3 % NaCl. Indigenous strans from Baranja region, Istria and two from eastern Slavonia are very tolerant on the high concentration of 4 % NaCl. According to results from ERIC-PCR method genetic similarity is not conditioned with location of the isolation. All strains are divided into two main groups with low relative similarity. The greatest genetic similarity were observed with strains that were isolated from Baranja region, easter Slavonia, Koprivnica and western Slavonia.

• Keywords: Glycine max (L.) Merrill; kvržične bakterije; fiksacija dušika; in vitro suša; salinitet; ERIC-PCR
• Keywords (english): Glycine max (L.) Merrill; root colonizing bacteria; nitrogen fixation; in vitro drought; salinity; ERIC-PCR
• Language: croatian
• URN:NBN: urn:nbn:hr:204:321300
• Study programme: Title: Agroecology; Study programme type: university; Study level: graduate; Academic / professional title: magistar/ magistra inženjer/inženjerka agroekologija (magistar/ magistra inženjer/inženjerka agroekologija)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2018-09-26 12:47:19