scholarly journals Effects of plant growth-promoting rhizobacteria on co-inoculation with Bradyrhizobium in soybean crop: a meta-analysis of studies from 1987 to 2018

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e7905 ◽  
Author(s):  
Douglas M. Zeffa ◽  
Lucas H. Fantin ◽  
Alessandra Koltun ◽  
André L.M. de Oliveira ◽  
Maria P.B.A. Nunes ◽  
...  
Keyword(s):  
Plant Growth ◽  
Grain Yield ◽  
Root Biomass ◽  
Meta Analysis ◽  
Plant Growth Promoting Rhizobacteria ◽  
Shoot Biomass ◽  
Experimental Conditions ◽  
Nodule Biomass ◽  
Plant Growth Promoting ◽  
Growth Promoting

Background The co-inoculation of soybean with Bradyrhizobium and other plant growth-promoting rhizobacteria (PGPR) is considered a promising technology. However, there has been little quantitative analysis of the effects of this technique on yield variables. In this context, the present study aiming to provide a quantification of the effects of the co-inoculation of Bradyrhizobium and PGPR on the soybean crop using a meta-analysis approach. Methods A total of 42 published articles were examined, all of which considered the effects of co-inoculation of PGPR and Bradyrhizobium on the number of nodules, nodule biomass, root biomass, shoot biomass, shoot nitrogen content, and grain yield of soybean. We also determined whether the genus of the PGPR used as co-inoculant, as well as the experimental conditions, altered the effect size of the PGPR. Results The co-inoculation technology resulted in a significant increase in nodule number (11.40%), nodule biomass (6.47%), root biomass (12.84%), and shoot biomass (6.53%). Despite these positive results, no significant increase was observed in shoot nitrogen content and grain yield. The response of the co-inoculation varied according to the PGPR genus used as co-inoculant, as well as with the experimental conditions. In general, the genera Azospirillum, Bacillus, and Pseudomonas were more effective than Serratia. Overall, the observed increments were more pronounced under pot than that of field conditions. Collectively, this study summarize that co-inoculation improves plant development and increases nodulation, which may be important in overcoming nutritional limitations and potential stresses during the plant growth cycle, even though significant increases in grain yield have not been evidenced by this data meta-analysis.

scholarly journals Morphological and Metabolite Responses of Potatoes under Various Phosphorus Levels and Their Amelioration by Plant Growth-Promoting Rhizobacteria

2021 ◽  
Vol 22 (10) ◽  
pp. 5162
Author(s):  
Leangsrun Chea ◽  
Birgit Pfeiffer ◽  
Dominik Schneider ◽  
Rolf Daniel ◽  
Elke Pawelzik ◽  
...  
Keyword(s):  
Amino Acids ◽  
Plant Growth ◽  
Plant Growth Promoting Rhizobacteria ◽  
Shoot Biomass ◽  
Root Surface Area ◽  
Limiting Factor ◽  
P Availability ◽  
P Deficiency ◽  
Plant Growth Promoting ◽  
Growth Promoting

Low phosphorus (P) availability is a major limiting factor for potatoes. P fertilizer is applied to enhance P availability; however, it may become toxic when plants accumulate at high concentrations. Therefore, it is necessary to gain more knowledge of the morphological and biochemical processes associated with P deficiency and toxicity for potatoes, as well as to explore an alternative approach to ameliorate the P deficiency condition. A comprehensive study was conducted (I) to assess plant morphology, mineral allocation, and metabolites of potatoes in response to P deficiency and toxicity; and (II) to evaluate the potency of plant growth-promoting rhizobacteria (PGPR) in improving plant biomass, P uptake, and metabolites at low P levels. The results revealed a reduction in plant height and biomass 60–80% under P deficiency compared to P optimum. P deficiency and toxicity conditions also altered the mineral concentration and allocation in plants due to nutrient imbalance. The stress induced by both P deficiency and toxicity was evident from an accumulation of proline and total free amino acids in young leaves and roots. Furthermore, root metabolite profiling revealed that P deficiency reduced sugars by 50–80% and organic acids by 20–90%, but increased amino acids by 1.5–14.8 times. However, the effect of P toxicity on metabolic changes in roots was less pronounced. Under P deficiency, PGPR significantly improved the root and shoot biomass, total root length, and root surface area by 32–45%. This finding suggests the potency of PGPR inoculation to increase potato plant tolerance under P deficiency.

Plant growth promoting rhizobacteria are more effective under drought: a meta-analysis

2017 ◽  
Vol 416 (1-2) ◽  
pp. 309-323 ◽  
Author(s):  
Rachel L. Rubin ◽  
Kees Jan van Groenigen ◽  
Bruce A. Hungate
Keyword(s):  
Plant Growth ◽  
Meta Analysis ◽  
Plant Growth Promoting Rhizobacteria ◽  
Plant Growth Promoting ◽  
Growth Promoting

The growth-promoting effects of a bacterial endophyte on lodgepole pine are partially inhibited by the presence of other rhizobacteria

1998 ◽  
Vol 44 (10) ◽  
pp. 980-988 ◽  
Author(s):  
Elizabeth Bent ◽  
Christopher P Chanway
Keyword(s):  
Plant Growth ◽  
Growth Promotion ◽  
Lodgepole Pine ◽  
Primary Root ◽  
Biomass Accumulation ◽  
Plant Growth Promoting Rhizobacteria ◽  
Shoot Biomass ◽  
Bacillus Polymyxa ◽  
Plant Growth Promoting ◽  
Growth Promoting

To test the hypothesis that rhizobacteria naturally present in soils may interfere with the extent of root colonization and plant growth promotion by plant growth-promoting rhizobacteria (PGPR), we studied two lodgepole pine PGPR (Bacillus polymyxa strains L6 and Pw-2) when inoculated singly and when coinoculated with a non-PGPR competitor (Curtobacterium flaccumfaciens PF322). Bacillus polymyxa Pw-2 and Curtobacterium flaccumfaciens PF322 were consistently found as endophytes, while Bacillus polymyxa L6 was never found within the root interior. Strains Pw-2 and L6 differed in the rate and type of growth promotion. Strain Pw-2 increased root growth (branching and elongation) and shoot biomass accumulation 6 and 9 weeks, respectively, after inoculation, while strain L6 increased primary root elongation and root biomass accumulation after 12 weeks. Seedlings coinoculated with Pw-2 and PF322 had decreased shoot biomass and primary root lengths when compared with seedlings inoculated only with Pw-2. This effect was not linked to a decrease in the population size of Pw-2 in the rhizosphere or in the root interior of coinoculated treatments. In contrast, strain L6-mediated growth promotion was not impaired by coinoculation with PF322. Strain L6 did interfere to some degree with the growth-promoting capability of strain Pw-2. These results indicate that endophytic PGPR may be less adapted to microbial competition than external root-colonizing PGPR, and that the efficacy of endophytic PGPR may be reduced by the presence of other bacteria on external or internal root tissues.Key words: PGPR, endophytes, colonization, coinoculation, competition.

Growth of lentil (Lens culinaris Medikus) as influenced by phosphorus, Rhizobium and plant growth promoting rhizobacteria

2016 ◽  
Author(s):  
Guriqbal Singh ◽  
Narinder Singh ◽  
Veena Khanna
Keyword(s):  
Plant Growth ◽  
Grain Yield ◽  
Plant Height ◽  
Dry Matter ◽  
Block Design ◽  
Plant Growth Promoting Rhizobacteria ◽  
Dry Matter Accumulation ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Phosphorus Application

The experiment was conducted to study the effect of four levels of phosphorus (0, 20, 30 and 40 kg P2O5 ha-1) and four biofertilizer treatments [uninoculated control, Rhizobium, plant growth promoting rhizobacteria (PGPR) and Rhizobium + PGPR] on growth and grain yield of lentil. The experiment was conducted in factorial randomized complete block design (RCBD) with three replications. The periodic data recorded at 30, 60, 90, 120 days after sowing (DAS) and at harvest showed that the highest growth in various parameters i.e. plant height, branches plant-1 and shoot dry matter accumulation was recorded with application of 40 kg P2O5 ha-1, however, it was at par with 30 P2O5 ha-1. Among the biofertilizers, Rhizobium + PGPR treatment gave maximum values of growth parameters like plant height, branches plant-1 and shoot dry matter accumulation at all the stages. At 30-60 DAS, the maximum crop growth rate (CGR) was recorded with the application of 40 kg P2O5 ha-1 (71.3 kg ha-1 day-1) and co-inoculation of Rhizobium and PGPR (72.0 kg ha-1 day-1). Application of 40 P2O5 ha-1 and use of coinoculation (Rhizobium + PGPR) provided the highest grain yields. The study highlights the importance of phosphorus application and biofertilizers inoculation for improving the growth and grain yield of lentil.

Plant growth promoting rhizobacteria for winter wheat

1990 ◽  
Vol 36 (4) ◽  
pp. 265-272 ◽  
Author(s):  
J. Renato de Freitas ◽  
James J. Germida
Keyword(s):  
Plant Growth ◽  
Winter Wheat ◽  
Seedling Emergence ◽  
Leptosphaeria Maculans ◽  
Plant Growth Promoting Rhizobacteria ◽  
Shoot Biomass ◽  
Pseudomonas Cepacia ◽  
Plant Growth Promoting ◽  
Growth Promoting

The association of winter wheat (Triticum aestivum L. cv. Norstar) with root-colonizing bacteria (rhizobacteria) was studied in potted soil experiments in the growth chamber. Thirty-six known bacteria, some of which have been reported to stimulate plant growth, and 75 isolates obtained from the rhizosphere of winter wheat were tested for their effects on plant growth and development in two different soils. Two known bacteria and 12 isolates stimulated growth of winter wheat. Of these, the most effective were nine isolates that significantly (P < 0.01) increased plant height, root and shoot biomass, and number of tillers. The plant growth promoting effects of isolates were different in the two soils. Three of these strains were tentatively classified as Pseudomonas aeruginosa, and two each as Pseudomonas cepacia, Pseudomonas fluorescens, and Pseudomonas putida. Some isolates induced significant increases in seedling emergence rates and (or) demonstrated antagonism in vitro against Rhizoctonia solani and Leptosphaeria maculans. These results demonstrate the potential use of plant growth promoting rhizobacteria as inoculants for winter wheat. Key words: pseudomonads, plant growth promoting rhizobacteria, winter wheat, rhizosphere, bacterial inoculants.

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