College of Education for Pure Science

Master Thesis Viva in College of Education for Pure Science entitled “Isolation and Characterization of Local Isolates of Rhizobial Bacteria and Study Their Antimicrobial Activity”The College of Education for Pure Science, University of Mosul, has done the Master Thesis Viva entitled ” Isolation and Characterization of Local Isolates of Rhizobial Bacteria and Study Their Antimicrobial Activity “,On Thursday, June 16, 2022, the College staff including the respected Dean of the College, Assistant Professor Dr. Qais Ismail Ibrahim, the Honorable Scientific Associate and Administrative Associate, the Honorable Head of the Department of Biology, and a number of the college’s teachers were attended the viva. This study, presented by the master student Omar Hammad Jumaah in the Department of Biology, a 42 different rhizobial isolates were obtained and purified from a nitrogen fixer plants were collected from root nodules plants of different culturals and areas in Nineveh, Al- Anbar and Baghdad Governorates and from Duhok-Kurdistsn/Iraq. Rhizobial isolates OJ27, OJ29 which isolated from Bauhinia purpuria L., a genera and species are still unkown and were not mentioned in literatures up to date. For a first time in the world (up to our knowledge), isolation of rhizobial isolates OJ30 from Catalpa speciose L. Biochemical tests revealed that ability of all isolates of motility and growing on RMM, whereas isolates were variant in their ability to liquefy gelatin. All the isolates were able to utilize citrate as a sole carbon source, with the exception of R. grahamii OJ26, OJ35 which were isolated from Leucaena leucocephala L. and Bauhinia purpuria L., respectively. Most of the isolates showed a positive result for TSI test. Sugar alcohol mannitol were preferred by all the rhizobial isolates as a sole carbon source. Most of the isolates tolerated NaCl up to 6.0% concentration, with the exception of the isolates Mesorhizobium loti OJ33 which were sensitive to this concentration. There were variations in sensitivity and resistance to studied antibiotics, All the isolates showed sensitivity to Ciprofloxacin 10 µg/ml. There was variation in resistance against heavy metals. Most of the isolates showed a clear resistance to Pb (CH3COO)2 (100 µg/ml). All the isolates showed a positive result for production of cell surface molecules and the maximum EPS production average were 280 mg/ml by the isolate R. leguminosarum bv. viciae OJ4. Antimicrobial activity study revealed that a maximum mean inhibition zone was 16.6 mm when a filtrate culture OJ31 rhizobial isolated from root nodules of Parkinsonia aculata L. against Candida albicans AS43. A maximum mean inhibition zone value was 13.3 mm when a filtrate culture of OJ6 applied against a pathogenic fungi Aspergillus niger BI1. Results of aligment of DNA sequencing of polymerase chain reaction (PCR) products of the partial sequence of the gene 16S rRNA of the four selected rhizobial strains under study with standard strains recorded in the Gene Bank reaveled that Unknown Query_12861 isolate corresponded 98.55% with Rhizobium nepotum 39/7 NR 117203.1, whereas Unknown Query_22767 isolate were corresponded 98.12% with Rhizobium leguminosarum bv. viciae USDA 2370 NR_118339.1. Regarding Unknown Query_70219 isolate were 98.42% correspond with Rhizobium glycinendophyticum NR_165782.1. The percentage of corresponding of Lel Query_16169 were 97.89% with Rhizobium leguminosarum strain LMG 14904. The Viva committee was chaired by Asst. Prof. Dr. Najdat Bahjat Mahde/ University of Kerkuk/College of Education for Pure Sciences and the membership of Asst. Prof. Dr. Nada Fadil Abdul-Majeed/ University of Ninevah/College of Medicine, Dr. Hassan Faisal Hussain/ University of Mosul/College of Education for Pure Sciences and under the supervision and membership of both Asst. Prof. Dr. Raad Hassani Sultan Allawy / Mosul University/College of Education for Pure Sciences and Asst. Prof. Dr. Mahde Saleh Assafi/University of Duhok/ College of Science.