Hornworts Endosymbiosis in diatoms Rhopalodia gibba, a diatom alga, is a eukaryote with cyanobacterial N-fixing endosymbiont organelles. The spheroid bodies reside in the cytoplasm of the diatoms and are inseparable from their hosts.
Twenty four isolates were evaluated for colony and cellular morphology, pigment production and metabolic activities. Cluster analysis showed three main groups based on DNA fingerprints.
Comparison between ribotypes generated by isolates and in silico restriction of 16S rDNA partial sequences with same restriction enzymes was done with Gen Workbench v. Isolate C5T from tomato Lycopersicon esculentum grown soils presented the same in silico restriction patterns with A.
Isolate C5CO from cauliflower Brassica oleracea var. In this work we demonstrated the utility of molecular techniques and bioinformatics tools as a support to conventional techniques in characterization of the genus Azotobacter from vegetable-grown soils.
Azotobacter are heterotrophic and aerobic bacteria and their main property is the ability to fix nitrogen non-symbiotically, with a genomic content of G-C of 63— Their agronomic importance is due to the capability of synthesizing antibiotics, plant growth promotion substances 21242530vitamins, exopolysaccharides and pigment production 828besides their antagonist effect against pathogens They also have the ability to solubilize phosphates in aquaculture systems, vermicompost production and potato Solanum tuberosum grown soils 912 In Colombia, it has been used as bacterial inoculants in the culture of Dendranthema grandiflora, Stevia rebaudiana, vegetables and cotton 611 Characterization of Azotobacter species becomes difficult due to the morphological similarity that exists with other FNFB like Derxia, Azomonas and Beijerinckia, in addition to its interspecific biochemical ambiguity.
For that reason, in the last years authors like Aquilanti et al. This interest is focused towards the validation of fast and reliable molecular methodologies for quality control on agricultural biofertilizers.
In this context, amplified ribosomal DNA restriction analysis ARDRA was evaluated for the characterization of Azotobacter isolated from organic vegetable-grown soils, with the purpose of generating a molecular approach to this genus in Colombian agro-ecosystems.
Five random samples each of g were withdrawn from 10—15 cm depth and sieved through a 4. Soil pH was measured according to Van Lierop 38analyzing samples fully suspended in distilled water 1: The primary isolation was made using the grain soil technique Figure 1A according to the methodology previously described by Aquilanti et al.
Pigment production was observed by growing the cultures in Ashby agar with 0. Biochemical identification was carried out in triplicate using different sources of carbon:Biological nitrogen fixation (BNF) is the process whereby atmospheric nitrogen is reduced to ammonia in the presence of nitrogenize.
Nitrogenize is a biological catalyst found naturally only in certain microorganisms such as the symbiotic Rhizobium and Frankia, or the free-living Azospirillum and Azotobacter and BGA.
Over the last several decades, there have been a large number of studies done on the genetics, biochemistry, physiology, ecology, and agronomics of the bacteria forming nitrogen-fixing symbioses with legumes.
These bacteria, collectively referred to as the rhizobia, are taxonomically and. Nitrogen fixation. Nitrogen fixation is the process through which select heterotrophic and phototrophic microorganisms covert N2 gas to either ammonium or organic nitrogen (Jaffe, ).
Isolation of nitrogen-fixing bacteria. Plants were surface sterilized with 70% ethanol ( to 1 min) and 1 to 2% NaOCl ( to 15 min) according to the age of the plant and the type of plant tissue, washed with sterilized water, and macerated with a mortar, a pestle, and sterilized quartz sand.
Biological nitrogen fixation plays an important role in the nitrogen balance of agricultural ecosystems and provides an essential part of nitrogen nutrition for . Nitrogen fixation is carried out naturally in the soil by a wide range of nitrogen fixing Bacteria and Archaea, including Azotobacter.
Some nitrogen-fixing bacteria have symbiotic relationships with some plant groups, especially legumes.