Osmotolerance of diazotrophic rhizosphere bacteria

Hartmann, Anton; Prabhu, S. R.; Galinski, Erwin A.

doi:10.1007/978-94-011-3486-6_28

Cited by 16 publications

(11 citation statements)

References 9 publications

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“…The similar behavior of strains Az39 and Az19 under mild stress conditions (tested with PEG) may be due to other mechanisms different to trehalose production, such as glutamate (Hartmann et al, 1991) and glycine betaine accumulation (Csonka, 1989) which can also act as osmoprotectants of the cell in situations of stress.…”

Section: Tolerance Of the Strains To Osmotic Stressmentioning

confidence: 97%

In vitro PGPR properties and osmotic tolerance of different Azospirillum native strains and their effects on growth of maize under drought stress

García¹,

Maroniche

Creus

et al. 2017

Microbiological Research

165

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Osmotic variations in the soil can affect bacterial growth diminishing the number of inoculated bacteria. In a scenario of water deficit having tolerant bacteria would be beneficial to achieve a better response of the plant to stress. Thus, selection of more resistant bacteria could be useful to design new inoculants to be used in arid zones. In this sense, a group of Azospirillum isolates deposited in INTA collection was characterized in order to select strains tolerant to osmotic stress. The results obtained demonstrated that Az19 strain has similar in vitro PGPR characteristics to Az39, the most used strain in Argentina for inoculants industries, with the advantage of a better tolerance to osmotic and salt stress. Inoculation of maize plants with this strain resulted in a better response against water deficit compared to Az39 strain, encouraging us to further study the behavior of this strain in greenhouse and field trials in view of developing new inoculants suitable for areas with water deficit.

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Section: Tolerance Of the Strains To Osmotic Stressmentioning

confidence: 97%

In vitro PGPR properties and osmotic tolerance of different Azospirillum native strains and their effects on growth of maize under drought stress

García¹,

Maroniche

Creus

et al. 2017

Microbiological Research

165

View full text Add to dashboard Cite

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“…An exoenzyme of similar characteristics was reported for Zymomonas mobilis (Preziosi et al 1990), a bacterium phylogenetically related to the family Acetobacteraceae. No saccharolytic activity was detected in crude extracts, and further studies are needed to clarify the mechanisms responsible for osmoprotection, since sucrose was found to be the compatible solute in Acetobacter diazotrophicus (Hartmann et al 1991).…”

Section: Extracellular Saccharolytic Activitymentioning

confidence: 97%

“…2. Uptake induction by osmotic stress was assayed on cells grown in the presence of polyethyleneglycol, since according to Hartmann et al (1991), the compatible solute accumulated in Acetobacter diazotrophicus is sucrose. The need for transport energyzation through glucose dehydrogenase (van Schie et al 1987) was tested by adding glucose to the incubation mixture.…”

Section: Sucrose Uptakementioning

confidence: 99%

Metabolic characterization ofAcetobacter diazotrophicus

Álvarez¹,

Martinez-Drets²

1995

Can. J. Microbiol.

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Carbon and nitrogen metabolism were investigated in Acetobacter diazotrophicus Pal 3, a N2-fixing bacterium able to grow at low pH and at high sugar concentration. Enzymatic, respiratory, and uptake studies were performed. The main active pathway for the catabolism of phosphorylated glucose was the pentose phosphate pathway. In addition, A. diazotrophicus directly oxidized glucose, gluconate, and ketogluconates through respiratory chain-linked enzymes. Soluble enzymes for the oxidation of glucose and gluconate were also found. Acetobacter diazotrophicus had a complete tricarboxylic acid cycle with a respiratory chain-linked malate dehydrogenase. The ability to grow on two- and three-carbon substrates would be explained by the presence of gluconeogenesis. Lack of bacterial growth on dicarboxylates was explained by the absence of a transport system. Ammonium assimilation proceeded mainly through glutamate dehydrogenase under ammonium excess but also through energy-demanding glutamine synthetase and glutamate synthase under N2-fixing conditions. Acetobacter diazotrophicus was not able to transport sucrose and its ability to grow on this disaccharide was explained by the presence of an extracellular enzyme with saccharolytic activity.Key words: Acetobacter diazotrophicus, carbon–nitrogen metabolism, extracellular saccharolytic activity, sucrose–succinate uptake.

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“…Comparisons of osmotolerance in diVerent species of Azospirillum revealed that it increased in the order A. amazonense, A. lipoferum, A. brasilense, A. irakense, A. halopraeferens (Hartmann and Zimmer 1994;Hartmann et al 1991). Isolation of diazotrophs from the rhizosphere and rhizoplane of the salt-tolerant Kallar grass grown in Pakistan revealed the presence of A. brasilense and A. halopraeferens (Reinhold et al 1987).…”

Section: Introductionmentioning

confidence: 95%

Identification of salt stress inducible genes that control cell envelope related functions in Azospirillum brasilense Sp7

2007

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Plant growth promoting rhizobacteria such as Azospirillum brasilense are agronomically important as they are frequently used for crop inoculation. But adverse factors such as increasing soil salinity limit their survival, multiplication and phytostimulatory effect. In order to understand the role of the genes involved in the adaptation of A. brasilense Sp7 to salt stress, a mutant library (6,800 mutants) was constructed after random integration of a mini-Transposon Tn5 derivative containing a promoterless gusA and oriV. The library was screened for salt stress inducible Gus activity on minimal malate agar medium containing NaCl and 5-bromo-4-chloro-3-indolyl-beta-D: -glucuronide. Salt stress responsiveness of the promoters was estimated by quantifying GusA activity in the presence and absence of NaCl stress using p-nitrophenyl-beta-D: -glucuronide as a substrate. In 11 mutants showing high levels of gusA expression in the presence of salt-stress, the partial nucleotide sequence of the DNA region flanking the site of Tn5 insertion was determined and analysed using the NCBI-BLAST programs. Similarity searches revealed that 10 out of the 11 genes sequenced showed notable similarity with genes involved in functions related to modulation in the composition of exopolysaccharides, capsular polysaccharides, lipopolysaccharides, peptidoglycan and lipid bilayer of the cell envelope. Induction of cell envelope related genes in response to salt stress and salt sensitive phenotype of several mutants in A. brasilense indicate a prominent role of cell envelope in salt-stress adaptation.

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Osmotolerance of diazotrophic rhizosphere bacteria

Cited by 16 publications

References 9 publications

In vitro PGPR properties and osmotic tolerance of different Azospirillum native strains and their effects on growth of maize under drought stress

In vitro PGPR properties and osmotic tolerance of different Azospirillum native strains and their effects on growth of maize under drought stress

Metabolic characterization ofAcetobacter diazotrophicus

Identification of salt stress inducible genes that control cell envelope related functions in Azospirillum brasilense Sp7

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