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.

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.

Loblolly pine seedling growth after inoculation with plant growth-promoting rhizobacteria and ozone exposure

2004 ◽  
Vol 34 (7) ◽  
pp. 1410-1416 ◽  
Author(s):  
B L Estes ◽  
S A Enebak ◽  
A H Chappelka
Keyword(s):  
Plant Growth ◽  
Loblolly Pine ◽  
Plant Growth Promoting Rhizobacteria ◽  
Field Trials ◽  
Root Surface ◽  
Ozone Exposure ◽  
Root Surface Area ◽  
Foliar Injury ◽  
Plant Growth Promoting ◽  
Growth Promoting

Plant growth-promoting rhizobacteria promote plant growth and induce biocontrol, but are affected by soil type, water stress, microbial competition, and environmental conditions. One unexplored factor is the interaction of rhizobacteria-inoculated plants exposed to ozone. Loblolly pine (Pinus taeda L.) seeds were inoculated with either Bacillus subtilis (Ehrenberg) Cohn or Paenibacillus macerans (Schardinger) Ash. In field trials, 4-week-old seedlings were exposed for 12 weeks to carbon-filtered (CF ≈ 12 ppb), 1× (≈46 ppb), or 2× (≈97 ppb) ozone for 12 h·d–1 in open-top chambers (OTC) in 1998 and 1999. In three greenhouse trials, 5-week-old seedlings were exposed to ozone at 0× (≈8 ppb), 1× (≈105 ppb), 2× (≈199 ppb), and 3× (≈298 ppb) for 4 h·d–1, 5 d·week–1 for 8 weeks in continuously stirred tank reactors (CSTR). In both the CSTRs and the OTCs, ozone-exposed seedlings exhibited 20%–50% less biomass and more foliar injury as compared with nonexposed seedlings. In CSTRs, at the 3× exposure, B. subtilis-inoculated seedlings had 12% less foliar injury than noninoculated seedlings. Foliar injury was 65% less for B. subtilis-treated seedlings in 1998, and root surface area, total root length, and root diameter was 25%–35% greater when seedlings were exposed to 2× ozone in the OTCs. This is the first report of rhizobacteria protecting seedlings against the negative effects of ozone exposure.

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.

Amino acids profiling in Datura stramonium and study of their variations after inoculation with plant growth promoting Rhizobacteria

Biologia ◽  
2019 ◽  
Vol 74 (10) ◽  
pp. 1373-1383
Author(s):  
Bilal Rahmoune ◽  
Izzeddine Zakarya Zerrouk ◽  
Saad Bouzaa ◽  
Abdelkader Morsli ◽  
Madjda Khelifi-Slaoui ◽  
...  
Keyword(s):  
Amino Acids ◽  
Plant Growth ◽  
Plant Growth Promoting Rhizobacteria ◽  
Datura Stramonium ◽  
Plant Growth Promoting ◽  
Growth Promoting

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 Water Stress Amelioration and Plant Growth Promotion in Capsicum Plants by Osmotic Stress Tolerant Bacteria

2019 ◽  
pp. 1-12 ◽  
Author(s):  
Shweta Gupta ◽  
Rajesh Kaushal ◽  
Gaurav Sood ◽  
Bhawna Dipta ◽  
Shruti Kirti ◽  
...  
Keyword(s):  
Water Stress ◽  
Plant Growth ◽  
Growth Promotion ◽  
Field Capacity ◽  
Plant Growth Promoting Rhizobacteria ◽  
In Vivo Studies ◽  
Shoot Biomass ◽  
Plant Growth Promoting ◽  
Growth Promoting

The present study was initiated with testing of fifteen previously isolated indigenous plant growth promoting rhizobacteria for drought tolerance. Among all, two best isolates Pseudomonas aeruginosa (JHA6) and Bacillus amyloliquefaciens (ROH14) were selected for in-vivo studies. A total of ten treatments comprising Plant growth promoting rhizobacteria (PGPR) (JHA6 and ROH14) inoculated plants held at 80%, 60% and 40% field capacity (FC) soil moisture level was laid down in Completely Randomized Design with three replications. Un-inoculated plants held at various stress levels and non-stressed conditions (100% FC) served as control. In general, both the bacteria could promote Capsicum growth in terms of increase in root and shoot biomass, height of plants, chlorophyll content as well as increase in nutrient content and uptake. Besides, the bacterial inoculated Capsicum plants could withstand water stress more efficiently as indicated by increases in leaf area, total soluble proteins and relative water content of treated water stressed plants in comparison to untreated stressed ones. Enhanced antioxidant responses were evident as elevated activities of enzymes such as superoxide dismutase, catalase and peroxidase was recorded. Therefore, the ability of Capsicum plants to tolerate water stress is enhanced by application of the isolated bacteria which also function as plant growth promoting rhizobacteria.

scholarly journals Identification of Chemotaxis Compounds in Root Exudates and Their Sensing Chemoreceptors in Plant-Growth-Promoting Rhizobacteria Bacillus amyloliquefaciens SQR9

2018 ◽  
Vol 31 (10) ◽  
pp. 995-1005 ◽  
Author(s):  
Haichao Feng ◽  
Nan Zhang ◽  
Wenbin Du ◽  
Huihui Zhang ◽  
Yunpeng Liu ◽  
...  
Keyword(s):  
Amino Acids ◽  
Plant Growth ◽  
Organic Acids ◽  
Root Exudates ◽  
Bacillus Amyloliquefaciens ◽  
Plant Growth Promoting Rhizobacteria ◽  
Titration Calorimetry ◽  
Chemotaxis Proteins ◽  
Plant Growth Promoting ◽  
Growth Promoting

Chemotaxis-mediated response to root exudates, initiated by sensing-specific ligands through methyl-accepting chemotaxis proteins (MCP), is very important for root colonization and beneficial functions of plant-growth-promoting rhizobacteria (PGPR). Systematic identification of chemoattractants in complex root exudates and their sensing chemoreceptors in PGPR is helpful for enhancing their recruitment and colonization. In this study, 39 chemoattractants and 5 chemorepellents, including amino acids, organic acids, and sugars, were identified from 98 tested components of root exudates for the well-studied PGPR strain Bacillus amyloliquefaciens SQR9. Interestingly, mutant stain SQR9Δ8mcp, with all eight putative chemoreceptors completely deleted, lost the chemotactic responses to those 44 compounds. Gene complementation, chemotaxis assay, and isothermal titration calorimetry analysis revealed that McpA was mainly responsible for sensing organic acids and amino acids, while McpC was mostly for amino acids. These two chemoreceptors may play important roles in the rhizosphere chemotaxis of SQR9. In contrast, the B. amyloliquefaciens-unique chemoreceptor McpR was specifically responsible for arginine, and residues Tyr-78, Thr-131, and Asp-162 were critical for arginine binding. This study not only deepened our insights into PGPR–root interaction but also provided useful information to enhance the rhizosphere chemotaxis mobility and colonization of PGPR, which will promote their application in agricultural production.

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