Molecular characterization of nitrogen-fixing bacteria isolated from brazilian agricultural plants at São Paulo state

Reinhardt, Érica Lui; Ramos, Patricia; Manfio, Gilson Paulo; Barbosa, Heloíza Ramos; Pavan, C.; Moreira-Filho, Carlos Alberto

doi:10.1590/s1517-83822008000300002

Cited by 50 publications

(27 citation statements)

References 34 publications

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“…were isolated on liquid media, providing N 2 in the gas phase only. For all genera, this capability has already been described in other studies (5,10,38), whereas the autotrophic capabilities of Paenibacillus and Arsenicicoccus have not been reported yet. Members of these two genera have been isolated from samples collected in Friedrichshafen and at ESTEC (Paenibacillus ginsengisoli and Arsenicicoccus bolidensis) on media selective for autotrophic microorganisms.…”

Section: Discussionmentioning

confidence: 66%

Cultivation of Anaerobic and Facultatively Anaerobic Bacteria from Spacecraft-Associated Clean Rooms

Stieglmeier

Wirth²,

Kminek

et al. 2009

Appl Environ Microbiol

100

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In the course of this biodiversity study, the cultivable microbial community of European spacecraft-associated clean rooms and the Herschel Space Observatory located therein were analyzed during routine assembly operations. Here, we focused on microorganisms capable of growing without oxygen. Anaerobes play a significant role in planetary protection considerations since extraterrestrial environments like Mars probably do not provide enough oxygen for fully aerobic microbial growth. A broad assortment of anaerobic media was used in our cultivation strategies, which focused on microorganisms with special metabolic skills. The majority of the isolated strains grew on anaerobic, complex, nutrient-rich media. Autotrophic microorganisms or microbes capable of fixing nitrogen were also cultivated. A broad range of facultatively anaerobic bacteria was detected during this study and also, for the first time, some strictly anaerobic bacteria (Clostridium and Propionibacterium) were isolated from spacecraft-associated clean rooms. The multiassay cultivation approach was the basis for the detection of several bacteria that had not been cultivated from these special environments before and also led to the discovery of two novel microbial species of Pseudomonas and Paenibacillus.The major issue of planetary protection is to prevent the contamination of extraterrestrial environments by terrestrial biomolecules and life forms. Furthermore, reverse contamination of Earth by extraterrestrial material is also a fundamental concern (1). In order not to affect or even to confound future life detection missions on celestial bodies, which are of interest for their chemical and biological evolution, spacecraft are constructed in so-called clean rooms and are subject to severe cleaning processes and microbiological controls before launch (9). Therefore, these clean rooms are considered extreme environments for microorganisms (47).Detailed planetary protection protocols for missions to Mars were designed for the Viking missions, which were launched in 1975, and about 7,000 samples were taken from the two Viking spacecraft during prelaunch activities in order to determine the cultivable microbial load (37). Besides human-associated bacteria (pathogens and opportunistic pathogens), which were predominant among the microbes detected in these samples, aerobic spore-forming microorganisms (Bacillus) were found frequently on spacecraft and within the facilities.Spores are the resting states of bacteria and are often highly resistant to heat, desiccation, and other abiotic stresses. These multiresistance properties of such spore-forming microorganisms make them perfect candidates for surviving a space flight, and thus, the main focus of attention has been on them. Furthermore, only the detection of aerobic spore-forming bacteria is currently included in space agencies' planetary protection protocols for the quantitative determination of microbial burden on spacecraft.

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Section: Discussionmentioning

confidence: 66%

Cultivation of Anaerobic and Facultatively Anaerobic Bacteria from Spacecraft-Associated Clean Rooms

Stieglmeier

Wirth²,

Kminek

et al. 2009

Appl Environ Microbiol

100

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“…Some of the pesticides have direct effect on soil microbiological aspects, environmental pollution and health hazards (Martin et al, 2011). These pesticides may cause everlasting changes in the soil microflora (Aleem et al, 2003), adverse effect on soil fertility and crop productivity, inhibition of nitrogen (N2) fixing bacteria, (Sachin, 2009), interference with ammonification (Reinhardt et al, 2008). Several toxic and carcinogenic pesticides have banned in many of the countries including India.…”

Section: Introductionmentioning

confidence: 99%

Impact of Pesticides on PGPR Activity of Azotobacter sp. Isolated from Pesticide Flooded Paddy Soils

Chennappa¹,

Adkar-Purushothama²,

Naik³

et al. 2014

GJAS

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Azotobacter strains were isolated from paddy soils by serial dilution agar plate method.The colonies were glistening; smooth, slimy, brown to black in morphology on Jenson's N-free agar plates and the cells were Gram-negative bacteria. Biochemically, they were positive for indole production, citrate, catalase and Voges Proskauer test. Further, Nif gene sequence results revealed the presence of seven Azotobacter species. The effect of 1, 3 and 5% pesticides concentration viz., pendimethalin, chloropyrifos, glyphosate and phorate on nitrogen fixation, indole acetic acid, gibberllic acid, phosphate solubilization and bioassay of Azotobacter sp. were studied. Among all the species, GVT-1 strain was found to fix nitrogen at a maximum of 30µgN2 ml -1 day -1 , produced highest quantity gibberllic acid (10µg25ml -1 ) and able to solubilize the phosphate at the rate of 9.8cm by forming the halo zone which was supplemented with 5% phorate. Similarly, GVT-1 strain produced a highest amount of indole acetic acid (31.8µgml -1 ) in 5% pendimethalin. Further bioassay activities of GVT-1 strain found efficient in increasing the root, shoot length and vigor of the plant. From these results it is clear that the Azotobacter sp. not only produces plant growth promoting substances but is also resistant to different pesticides and is not affected by the bacterial activity.

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“…The structural gene nifH, as an important nif gene, is involved in the formation of the Fe-protein complex [9]. Nitrogenfixing bacteria can now be identified on the basis of the presence in their genome of nif DNA through PCR or sequencing techniques [10,11]. Due to the key role played by the nitrogen-fixing microorganisms in the agricultural soil and the importance of the metal zinc as an essential micronutrient in biological cycles along with its toxic effect on the environment, this study aimed at investigating the degree of sensitivity to different concentrations of zinc, in the form of ZnSO 4 , of nitrogen fixing microorganisms isolated from the rhizosphere of asparagus plants in a laboratory environment.…”

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confidence: 99%

Identification of ten N2-fixing bacteria using 16S rRNA and their response to various zinc concentrations

Dadook¹,

Mehrabian²,

Irian³

2013

International Journal of Cellular and Molecular Biotechnology

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Zinc is presently being used as a micronutrient essential for plant growth in agriculture in the form of zinc sulphate in fertilizers. Considering the importance of nitrogen-fixing microorganisms in soil fertility and plant growth, and the toxic effects of zinc, this study aimed at isolating nitrogen-fixing microorganisms from the asparagus rhizosphere arable soil and examining the sensitivity of the isolated strains to different zinc concentrations. The asparagus rhizosphere soil was cultivated in a nitrogen-free environment at 30 °C for 48 hours. Strains were identified by both biochemical and molecular methods. The presence of the nitrogenase enzyme system was confirmed by testing for the presence of the nifH gene through PCR analysis. The minimum inhibitory concentration (MIC) and optimal zinc concentration for the growth of each strain were also determined. A total of 10 different bacterial species were identified in three different soil samples. The presence of the nifH gene was confirmed in seven different strains. MIC and the average optimal zinc concentration for bacterial growth were 130.7 ppm and 13 ppm, respectively. The asparagus rhizosphere soil contains different species of nitrogen stabilizing microorganisms. An optimal zinc concentration in soil of 20 ppm is suggested.

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Molecular characterization of nitrogen-fixing bacteria isolated from brazilian agricultural plants at São Paulo state

Cited by 50 publications

References 34 publications

Cultivation of Anaerobic and Facultatively Anaerobic Bacteria from Spacecraft-Associated Clean Rooms

Cultivation of Anaerobic and Facultatively Anaerobic Bacteria from Spacecraft-Associated Clean Rooms

Impact of Pesticides on PGPR Activity of Azotobacter sp. Isolated from Pesticide Flooded Paddy Soils

Identification of ten N2-fixing bacteria using 16S rRNA and their response to various zinc concentrations

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