Airborne transmission of the rhizosphere bacteriumAzospirillum

Bashan, Yoav

doi:10.1007/bf02540228

Cited by 18 publications

(7 citation statements)

References 25 publications

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“…Enterobacter strains from potato tubers were all Gramnegative, oxidase negative, motile via flagella, and were able to fix nitrogen (Pishchik et al 1998). Azospirillum had previously been isolated from the roots of various plants including cereals, legumes, vegetables, and flowering plants (Döbereiner and Day 1976;Tyler et al 1979;Wong et al 1980;Bally et al 1983;Ladha et al 1987;Cavalcante and Döbereiner 1988;De Coninck et al 1988;Bashan 1991). In this study, A. brasilense was found to be the dominant species of Azospirillum on plant roots, and the possible variations might be due to selectivity of the host plant (Baldani and Döbereiner 1980).…”

Section: Resultsmentioning

confidence: 60%

Wheat root colonization and nitrogenase activity byAzospirillumisolates from crop plants in Korea

Kim¹,

Kecskés²,

Deaker³

et al. 2005

Can. J. Microbiol.

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Nitrogen-fixing bacteria were isolated from the rhizosphere of different crops of Korea. A total of 16 isolates were selected and characterized. Thirteen of the isolates produced characteristics similar to those of the reference strains of Azospirillum, and the remaining 3 isolates were found to be Enterobacter spp. The isolates could be categorized into 3 groups based on their ARDRA patterns, and the first 2 groups comprised Azospirillum brasilense and Azospirillum lipoferum. The acetylene reduction activity (ARA) of these isolates was determined for free cultures and in association with wheat roots. There was no correlation between pure culture and plant-associated nitrogenase activity of the different strains. The isolates that showed higher nitrogenase activities in association with wheat roots in each group were selected and sequenced. Isolates of Azospirillum brasilense CW301, Azospirillum brasilense CW903, and Azospirillum lipoferum CW1503 were selected to study colonization in association with wheat roots. We observed higher expression of beta-galactosidase activity in A. brasilense strains than in A. lipoferum strains, which could be attributed to their higher population in association with wheat roots. All strains tested colonized and exhibited the strongest beta-galactosidase activity at the sites of lateral roots emergence.

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Section: Resultsmentioning

confidence: 60%

Wheat root colonization and nitrogenase activity byAzospirillumisolates from crop plants in Korea

Kim¹,

Kecskés²,

Deaker³

et al. 2005

Can. J. Microbiol.

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“…Since Azospirillum strains were isolated from diverse geographical regions from tropical to temperate zones (6), temperature alone is unlikely to be the major limiting factor on the proliferation of native strains. Furthermore, as A. brasilense is apparently a nonspecific bacterium capable of colonizing numerous plant species (9), the growth of a particular plant species is probably not a requirement for survival.…”

Section: Discussionmentioning

confidence: 99%

Survival of Azospirillum brasilense in the Bulk Soil and Rhizosphere of 23 Soil Types

Bashan¹,

Puente²,

Rodríguez-Mendoza³

et al. 1995

Appl Environ Microbiol

158

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The survival of Azospirillum brasilense Cd and Sp-245 in the rhizosphere of wheat and tomato plants and in 23 types of plant-free sterilized soils obtained from a wide range of environments in Israel and Mexico was evaluated. Large numbers of A. brasilense cells were detected in all the rhizospheres tested, regardless of soil type, bacterial strain, the origin of the soil, or the amount of rainfall each soil type received prior to sampling. Survival of A. brasilense in soils without plants differed from that in the rhizosphere and was mainly related to the geographical origin of the soil. In Israeli soils from arid, semiarid, or mountain regions, viability of A. brasilense rapidly declined or populations completely disappeared below detectable levels within 35 days after inoculation. In contrast, populations in the arid soils of Baja California Sur, Mexico, remained stable or even increased during the 45-day period after inoculation. In soils from Central Mexico, viability slowly decreased with time. In all soils, percentages of clay, nitrogen, organic matter, and water-holding capacity were positively correlated with bacterial viability. High percentages of CaCO 3 and fine or rough sand had a highly negative effect on viability. The percentage of silt, pH, the percentage of phosphorus or potassium, electrical conductivity, and C/N ratio had no apparent effect on bacterial viability in the soil. Fifteen days after removal of inoculated plants, the remaining bacterial population in the three soil types tested began to decline sharply, reaching undetectable levels 90 days after inoculation. After plant removal, percolating the soils with water almost eliminated the A. brasilense population. Viability of A. brasilense in two artificial soils containing the same major soil components as the natural soils from Israel did was almost identical to that in the natural soils. We conclude that A. brasilense is a rhizosphere colonizer which survives poorly in most soils for prolonged periods of time; that outside the rhizosphere, seven abiotic parameters control the survival of this bacterium in the soil; and that disturbance of the soil (percolation with water or plant removal) directly and rapidly affects the population levels. Azospirillum species survive for prolonged periods of time in the rhizosphere of numerous plant species (13). Colonization of roots is nonspecific, and bacteria migrate between different plant species (7, 9, 18). However, conflicting evidence has been reported for survival of Azospirillum spp. in the soil outside the rhizosphere. Azospirillum spp. occur in most soils of tropical (3, 22, 23, 48, 51) and some soils of temperate (26) regions, indicating a high survivability outside the rhizosphere. In contrast, in studies done mainly in temperate and semiarid zones (1, 4, 15, 21, 52, 53), but also in tropical regions (41), it was found that introduced Azospirillum spp. survived poorly in these soils and hardly lasted from one season to the next (27). In Israeli soils, Azospirillum spp. adsorbed firmly ...

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“…Azospirillum has been previously isolated in various temperate zones (Bashan 1991a;De Coninck et al 1988). Recently, it was isolated from 10 graminoid root species and adjacent soil collected from tundra and semidesert sites in the Canadian High Arctic (Nosko et al 1994).…”

Section: New Host Plants For Isolation and For Inoculation Of The Bacmentioning

confidence: 99%

“…Apparently, contamination from Azospirilluminoculated plants may occur via airborne bacteria. The existence of an airborne phase in a rhizosphere bacterium like Azospirillum presents a risk of uncontrolled airborne contamination from inoculated rhizobacteria (Bashan 1991a) and should not be ignored.…”

Section: Airborne Transmissionmentioning

confidence: 99%

Azospirillum– plant relationships: environmental and physiological advances (1990–1996)

Bashan¹,

Holguín²

1997

Can. J. Microbiol.

Self Cite

547

268

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This review presents a critical and comprehensive analysis of the developments in environmental and physiological studies related to Azospirillum interactions with plants based on information published between 1990 and 1996. It was designed as an update of a previous review with a similar scope. Apart from an update, this review emphasizes the central issues of Azospirillum research today, such as coinoculation with other microorganisms and hormonal studies, shows the less researched areas, and proposes possible avenues for the exploitation of this bacterium in areas other than agriculture.Key words: Azospirillum, bacterial inoculation, plant–bacteria interaction, plant growth promoting rhizobacteria, rhizosphere bacteria.

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Airborne transmission of the rhizosphere bacteriumAzospirillum

Cited by 18 publications

References 25 publications

Wheat root colonization and nitrogenase activity byAzospirillumisolates from crop plants in Korea

Wheat root colonization and nitrogenase activity byAzospirillumisolates from crop plants in Korea

Survival of Azospirillum brasilense in the Bulk Soil and Rhizosphere of 23 Soil Types

Azospirillum– plant relationships: environmental and physiological advances (1990–1996)

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