Persistence in soil of the plant growth promoting rhizobacterium Pseudomonas putida GR12-2 and genetically manipulated derived strains

1995 ◽  
Vol 41 (6) ◽  
pp. 445-451 ◽  
Author(s):  
Weizhen Tang ◽  
J. J. Pasternak ◽  
Bernard R. Glick

Transformation of the plant growth promoting rhizobacterium Pseudomonas putida GR12-2 with broad-host-range vectors can affect the growth of the bacterium, its ability to promote root elongation of canola seedlings under gnotobiotic conditions, and its persistence in soil. Plasmid transformants, and a transposon-mutagenized derivative of P. putida GR12-2, fell into two classes with respect to these three attributes: strains that were clearly diminished in these capabilities and strains that behaved like the nontransformed wild type. These differences can be accounted for by the imposition of a metabolic load that is created by some types of genetic modification that results in a physiological impairment of the modified bacterium and decreases its ability to function as a plant growth promoting rhizobacterium.Key words: plant growth promoting rhizobacteria, PGPR, bacterial fertilizer, soil bacteria, soil persistence, microcosm.

1994 ◽  
Vol 40 (11) ◽  
pp. 911-915 ◽  
Author(s):  
Bernard R. Glick ◽  
Christian B. Jacobson ◽  
Melinda M. K. Schwarze ◽  
J. J. Pasternak

The plant growth promoting rhizobacterium Pseudomonas putida GR12-2 was mutagenized with nitrosoguanidine and three separate mutants that were unable to utilize 1-aminocyclopropane-1-carboxylic acid (ACC) as a sole nitrogen source were selected. These mutants are devoid of the ACC deaminase activity that is present in wild-type P. putida GR12-2 cells. Only wild-type cells, but not any of the ACC deaminase mutants, promoted root elongation of developing canola seedlings under gnotobiotic conditions. These results are interpreted in terms of a model in which P. putida GR12-2 promotes root elongation by binding to germinating seeds and sequesters and hydrolyzes some of the unbound ACC, thereby lowering the level of ACC and hence the endogenous ethylene concentration, allowing the roots to grow longer.Key words: 1-aminocyclopropane-1-carboxylate, ACC, plant growth promoting rhizobacteria, PGPR, ACC deaminase, bacterial fertilizer.


1991 ◽  
Vol 37 (10) ◽  
pp. 796-799 ◽  
Author(s):  
Yuwen Hong ◽  
J. J. Pasternak ◽  
Bernard R. Glick

Pseudomonas putida GR12-2, a plant growth promoting rhizobacterium, was transformed with the broad host range plasmid pGSS15. The presence of the plasmid caused (i) a decrease in cell generation times, (ii) an altered pattern of cell proteins, (iii) an inhibition of the enhancement of canola root elongation, (iv) impairment of nitrogen fixation, and (v) a decrease in siderophore production. Strains that were cured of pGSS15, on the other hand, re-established growth rates, levels of siderophore production, and canola root elongation capabilities equivalent to nontransformed P. putida GR12-2. Thus, the transforming plasmid imposes a metabolic load on the recipient bacteria that impacts on a number of different energy-dependent processes. Key words: plant growth promoting rhizobacteria, nitrogen fixation, Pseudomonas, transformation, metabolic load.


1995 ◽  
Vol 41 (9) ◽  
pp. 776-784 ◽  
Author(s):  
Xiuying Sun ◽  
Marilyn Griffith ◽  
J. J. Pasternak ◽  
Bernard R. Glick

The plant growth promoting rhizobacterium Pseudomonas putida GR12-2 was originally isolated from the rhizosphere of plants growing in the Canadian High Arctic. Here we report that this bacterium was able to grow and promote root elongation of both spring and winter canola at 5 °C, a temperature at which only a relatively small number of bacteria are able to proliferate and function. In addition, the bacterium survived exposure to freezing temperatures, i.e., −20 and −50 °C. In an effort to determine the mechanistic basis for this behaviour, it was discovered that following growth at 5 °C, P. putida GR12-2 synthesized and secreted to the growth medium a protein with antifreeze activity. Analysis of the spent growth medium, following concentration by ultrafiltration, by SDS-polyacrylamide gel electrophoresis revealed the presence of one major protein with a molecular mass of approximately 32–34 kDa and a number of minor proteins. However, at this point it is not known which of these proteins contains the antifreeze activity.Key words: plant growth promoting rhizobacteria, PGPR, bacterial fertilizer, soil bacteria, antifreeze protein.


2011 ◽  
Vol 356 (1-2) ◽  
pp. 217-230 ◽  
Author(s):  
Nele Weyens ◽  
Jana Boulet ◽  
Dirk Adriaensen ◽  
Jean-Pierre Timmermans ◽  
Els Prinsen ◽  
...  

2020 ◽  
Vol 19 (6) ◽  
pp. 15-29
Author(s):  
Yagmur Yilmaz ◽  
Ceknas Erdinc ◽  
Ahmet Akkopru ◽  
Selma Kipcak

Salt stress affects many aspects of plant metabolism and as a result, growth and yield are reduced. The aim in this study was to determine the effects of plant growth promoting rhizobacteria (PGPR) on tomato plants under salt stress. With this aim, the Interland F1 cv. and bacterial isolates of Bacillus thuringiensis CA41/1, Pseudomonas putida 18/1K, Pseudomonas putida S5/4ep, and Pseudomonas putida 30 were used. Salt application was completed in two different doses of 25 and 50 mM NaCl when seedlings reached the stage of 3 true leaves. At the end of the study, in addition to seedling development criteria, some nutrient element contents and rates (K, Ca, Na, K/Na and Ca/Na), superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) enzyme activities, malondialdehyde (MDA) and photosynthetic pigment contents were determined. In the stress environment, PGPR inoculation increased K content by up to 10%, while apart from isolate P. putida no.30, the other isolates lowered Na content by up to 18%. Additionally, 18/1K and S5/4ep isolates were identified to reduce membrane injury index by up to 97%. It was identified that CA41/1, 18/1K and S5/4ep isolates were more effective against salt stress, especially. In general, the plant tolerance levels induced by the bacteria were identified to increase with the increase in salt stress.


2002 ◽  
Vol 48 (3) ◽  
pp. 189-199 ◽  
Author(s):  
Andrei A Belimov ◽  
Vera I Safronova ◽  
Tetsuro Mimura

Responses of rape (Brassica napus var. oleifera L.) to inoculation with plant growth promoting rhizobacteria, Pseudomonas putida Am2, Pseudomonas putida Bm3, Alcaligenes xylosoxidans Cm4, and Pseudomonas sp. Dp2, containing 1-aminocyclopropane-1-carboxylate (ACC) deaminase were studied using growth pouch and soil cultures. In growth pouch culture, the bacteria significantly increased root elongation of phosphorus-sufficient seedlings, whereas root elongation of phosphorus-deficient seedlings was not affected or was even inhibited by the bacteria. Bacterial stimulation of root elongation of phosphorus-sufficient seedlings was eliminated in the presence of a high ammonia concentration (1 mM) in the nutrient solution. Bacterial effects on root elongation of potassium-deficient and potassium-sufficient seedlings were similar. The bacteria also decreased inorganic phosphate content in shoots of potassium- and phosphorus-sufficient seedlings, reduced ethylene production by phosphorus-sufficient seedlings, and inhibited development of root hairs. The effects of treatment with Ag+, a chemical inhibitor of plant ethylene production, on root elongation, ethylene evolution, and root hair formation were similar to bacterial treatments. The number of bacteria on the roots of phosphorus-deficient seedlings was not limited by phosphorus deficiency. In pot experiments with soil culture, inoculation of seeds with bacteria and treatment with aminoethoxyvinylglycine, an inhibitor of ethylene biosynthesis in plants, increased root and (or) shoot biomass of rape plants. Stimulation of plant growth caused by the bacteria was often associated with a decrease in the content of nutrients, such as P, K, S, Mo, and Ba, in shoots, depending on the strain used. The results obtained show that the growth-promoting effects of ACC-utilizing rhizobacteria depend significantly on the nutrient status of the plant.Key words: 1-aminocyclopropane-1-carboxylate deaminase, Brassica napus, PGPR, phosphorus uptake, plant-bacteria interaction, ethylene, Pseudomonas.


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