The mangrove flora consists of three separate regions in Myanmar: the Rakhine mangroves, Irrawaddy mangroves, and Taninthayi mangroves. Mangrove communities are recognized as highly productive ecosystems that provide large quantities of organic matter to adjacent costal water. Mangroves provide a unique ecological niche for different microbes, which play various roles in nutrient recycling as well as in various environmental activities. The highly productive and diverse microbial community living associated with mangrove ecosystems continuously transforms nutrients from dead mangrove material into sources of nitrogen, phosphorous and other nutrients. Those can be used by the plants and in turn plant-root exudates serve as a food source for the microbes. The major aim of this research work is to create the deactivated gene by antibiotic mutation for studying the interaction of nitrogen-fixation and alginate producing activity of Azotobacter vineladii isolate from mangrove rhizospheric soil.
A nitrogen fixation bacterium Azotobacter vinelandii was isolated from the mangrove rhizosphere soil of Irrawaddy Region, Myanmar. Screening and quantitative determination of the nitrogen fixation activity and alginate producing activity of the isolated strain was studied. The algD and algU gene fragments of Azotobacter vinelandii were isolated by using designated primers. A deletion was engineered in the cloned algD and algU genes by digestion with suitable restriction endonucleases and Kanamycin resistance gene cartridge was inserted. The mutation was subsequently transferred to the host bacteria, Azotobacter vinelandii by biparental mating using pEX18 vector and E.coli ST18 under pressure of kanamycin selection. Two mutant strains were developed and confirmed by PCR. It was observed that the resultant two mutant strains lost of their nitrogen fixation activity due to lost of their alginate producing activity.