scholarly journals Co-inoculation With Tropical Strains of Azospirillum and Bacillus Is More Efficient Than Single Inoculation for Improving Plant Growth and Nutrient Uptake in Maize.

Author(s):  
Vitoria Palhares Ribeiro ◽  
Eliane Aparecida Gomes ◽  
Sylvia Morais de Sousa ◽  
Ubiraci Gomes de Paula Lana ◽  
Antonio Marcos Coelho ◽  
...  

Abstract Usage of Bacillus and Azospirillum as new eco-friendly microbial consortium inoculants is a strategy to increase plant growth and crop yield by improving nutrient availability in agricultural systems. In this study, we designed a multispecies inoculum containing B. thuringiensis (strain B116), B. subtillis (strain B2084) and Azospirillum brasilense (strains A1626 and A2142) to investigate their individual or co-inoculated ability to solubilize and mineralize phosphate, produce indole acetic acid (IAA) and their effect on maize growth promotion in hydroponics and in a non-sterile soil. All strains showed significant IAA production, P mineralization (sodium phytate) and Ca-P, Fe-P (tricalcium phosphate and iron phosphate, respectively) solubilization. In hydroponics, co-inoculation with A1626 x A2142, B2084 x A2142, B2084 x A1626 resulted in higher root total length, total surface area, and surface area of roots with diameter between 0 and 1 mm than other treatments with single inoculant, except B2084. In a greenhouse experiment, maize inoculated with the two Azospirillum strains exhibited enhanced shoot dry weight, shoot P and K content, root dry weight, root N and K content and acid and alkaline phosphatase activities than the other treatments. There was a significant correlation between soil P and P shoot, alkaline phosphatase and P shoot and between acid phosphatase and root dry weight. It may be concluded that co-inoculations are most effective than single inoculants strains, mainly between two selected Azospirillum strains. Thus, they could have synergistic interactions during maize growth, and be useful in the formulation of inoculants to improve the cropping systems sustainable.

HortScience ◽  
1996 ◽  
Vol 31 (3) ◽  
pp. 453-457
Author(s):  
Venu G. Oddiraju ◽  
Caula A. Beyl ◽  
Philip A. Barker

Seedlings and microcuttings taken from two western black cherry (Prunus serotina var. virens Ehrh.) trees, one with profuse roots and one with scant roots, were grown in either normal or compacted soil to determine if the variation in the growth of fine and coarse roots under conditions of compaction could be attributed to genetic factors or method of propagation. An image processing system [Image Capture and Analysis System (ICAS)] was used to classify and measure the roots. There was a significant reduction in the surface area of fine roots, total surface area, and root dry weight after 12 weeks of compaction, but the effect on coarse roots was nonsignificant. Initial differences in the larger surface area of coarse roots of seedlings vs. for those of microcuttings disappeared over the course of the experiment. However, the surface areas of fine roots and the total surface area were significantly larger and root dry weight was higher for seedlings than for microcuttings, even at the end of the 12-week treatment period. The surface areas of fine and coarse roots, total surface area, and dry weight of roots were similar at the end of the experiment, regardless of genotype.


2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Geetha Rajendran ◽  
Maheshwari H. Patel ◽  
Sanket J. Joshi

One of the ways to increase the competitive survivability of rhizobial biofertilizers and thus achieve better plant growth under such conditions is by modifying the rhizospheric environment or community by addition of nonrhizobial nodule-associated bacteria (NAB) that cause better nodulation and plant growth when coinoculated with rhizobia. A study was performed to investigate the most commonly associated nodule-associated bacteria and the rhizospheric microorganisms associated with theFenugreek(Trigonella foenum-graecum) plant. Isolation of nonrhizobial isolates from root nodules ofFenugreekwas carried out along with the rhizospheric isolates. About 64.7% isolates obtained fromFenugreeknodules were gram-negative coccobacilli, 29.41% were gram-positive bacilli, and all rhizospheric isolates except one were gram-positive bacilli. All the isolates were characterized for their plant growth promoting (PGP) activities. Two of the NAB isolates M2N2c and B1N2b (Exiguobacterium sp.) showed maximum positive PGP features. Those NAB isolates when coinoculated with rhizobial strain—S. meliloti, showed plant growth promotion with respect to increase in plant’s root and shoot length, chlorophyll content, nodulation efficiency, and nodule dry weight.


2021 ◽  
Vol 51 (3) ◽  
Author(s):  
Claudyanne do Nascimento Costa ◽  
Jadson Emanuel Lopes Antunes ◽  
João Pedro Alves de Aquino ◽  
Ingrid Sthephanie da Costa Silva ◽  
Angela Celis de Almeida Lopes ◽  
...  

ABSTRACT: This study evaluated the activity of rhizobia isolates inoculated in large (18 mm) and small (11 mm) seeds on lima bean growth, nodulation and N fixation. Selected rhizobia isolates were compared with a reference strain CIAT899 and two controls without inoculation. Large seeds contributed for highest plant growth, nodulation and N fixation than small seeds. The isolates UFPI-59, UFPI-18 and UFPI-38 promoted the highest values of shoot and root dry weight, respectively. The isolates UFPI-32 promoted the highest values of nodule number, while UFPI-59 promoted the highest values of nodule dry weight. The isolates UFPI-38 and UFPI-59 promoted the highest accumulation of N. This study showed that seed size really influences lima bean growth, nodulation and BNF. Considering rhizobia isolates, UFPI-59, UFPI-38, and UFPI-18 contributed for plant growth, promoted better nodulation and effectiveness on biological N fixation.


2017 ◽  
Vol 66 (1) ◽  
pp. 57-65 ◽  
Author(s):  
Jian Zhang ◽  
Peng Cheng Wang ◽  
Ling Fang ◽  
Qi-An Zhang ◽  
Cong Sheng Yan ◽  
...  

Phosphorus is a major essential macronutrient for plant growth, and most of the phosphorus in soil remains in insoluble form. Highly efficient phosphate-solubilizing bacteria can be used to increase phosphorus in the plant rhizosphere. In this study, 13 isolates were obtained from waste mushroom residues, which were composed of cotton seed hulls, corn cob, biogas residues, and wood flour. NBRIP solid medium was used for isolation according to the dissolved phosphorus halo. Eight isolates produced indole acetic acid (61.5%), and six isolates produced siderophores (46.2%). Three highest phosphate-dissolving bacterial isolates, namely, M01, M04, and M11, were evaluated for their beneficial effects on the early growth of tomato plants (Solanum lycopersicum L. Wanza 15). Strains M01, M04, and M11 significantly increased the shoot dry weight by 30.5%, 32.6%, and 26.2%, and root dry weight by 27.1%, 33.1%, and 25.6%, respectively. Based on 16S rRNA gene sequence comparisons and phylogenetic positions, strains M01 and M04 belonged to the genus Acinetobacter, and strain M11 belonged to the genus Ochrobactrum. The findings suggest that waste mushroom residues are a potential resource of plant growth-promoting bacteria exhibiting satisfactory phosphate-solubilizing for sustainable agriculture.


2020 ◽  
Vol 8 (4) ◽  
pp. 496
Author(s):  
Dilfuza Egamberdieva ◽  
Vyacheslav Shurigin ◽  
Burak Alaylar ◽  
Hua Ma ◽  
Marina E. H. Müller ◽  
...  

The effects of biochar on plant growth vary depending on the applied biochar type, study site environmental conditions, microbial species, and plant–microbial interactions. The objectives of the present study were therefore to assess 1) the response of growth parameters of lupin and root disease incidence to the application of three biochar types in a loamy sandy soil, and 2) the role of endophytic bacteria in biological control of root rot disease incidence in lupin after the amendment of soil with different biochar types. As biochar types we tested (i) hydrochar (HTC) from maize silage, (ii) pyrolysis char from maize (MBC), and (iii) pyrolysis char from wood (WBC) at three different concentrations (1%, 2%, and 3% of char as soil amendments). There were no significant effects in lupin shoot and root growth in soils amended with WBC at any of the concentrations. MBC did not affect plant growth except for root dry weight at 2% MBC. HTC char at 2% concentration, significantly increased the root dry weight of lupin by 54–75%, and shoot dry weight by 21–25%. Lupin plants grown in soil amended with 2% and 3% WBC and MBC chars showed 40–50% and 10–20% disease symptoms, respectively. Plants grown in soil without biochar and with HTC char were healthy, and no disease incidence occurred. Pseudomonas putida L2 and Stenotrophomonas pavanii L8 isolates demonstrated a disease reduction compared to un-inoculated plants under MBC and WBC amended soil that was infested with Fusarium solani.


2019 ◽  
Vol 95 (9) ◽  
Author(s):  
Namis Eltlbany ◽  
Mohamed Baklawa ◽  
Guo-Chun Ding ◽  
Dinah Nassal ◽  
Nino Weber ◽  
...  

ABSTRACT Soil microbial communities interact with roots, affecting plant growth and nutrient acquisition. In the present study, we aimed to decipher the effects of the inoculants Trichoderma harzianum T-22, Pseudomonas sp. DSMZ 13134, Bacillus amyloliquefaciens FZB42 or Pseudomonas sp. RU47 on the rhizosphere microbial community and their beneficial effects on tomato plants grown in moderately low phosphorous soil under greenhouse conditions. We analyzed the plant mass, inoculant colony forming units and rhizosphere communities on 15, 22, 29 and 43 days after sowing. Selective plating showed that the bacterial inoculants had a good rhizocompetence and accelerated shoot and root growth and nutrient accumulation. 16S rRNA gene fingerprints indicated changes in the rhizosphere bacterial community composition. Amplicon sequencing revealed that rhizosphere bacterial communities from plants treated with bacterial inoculants were more similar to each other and distinct from those of the control and the Trichoderma inoculated plants at harvest time, and numerous dynamic taxa were identified. In conclusion, likely both, inoculants and the rhizosphere microbiome shifts, stimulated early plant growth mainly by improved spatial acquisition of available nutrients via root growth promotion. At harvest, all tomato plants were P-deficient, suggesting a limited contribution of inoculants and the microbiome shifts to the solubilization of sparingly soluble soil P.


mSphere ◽  
2020 ◽  
Vol 5 (4) ◽  
Author(s):  
Dario X. Ramirez-Villacis ◽  
Omri M. Finkel ◽  
Isai Salas-González ◽  
Connor R. Fitzpatrick ◽  
Jeffery L. Dangl ◽  
...  

ABSTRACT Glyphosate is a commonly used herbicide with a broad action spectrum. However, at sublethal doses, glyphosate can induce plant growth, a phenomenon known as hormesis. Most glyphosate hormesis studies have been performed under microbe-free or reduced-microbial-diversity conditions; only a few were performed in open systems or agricultural fields, which include a higher diversity of soil microorganisms. Here, we investigated how microbes affect the hormesis induced by low doses of glyphosate. To this end, we used Arabidopsis thaliana and a well-characterized synthetic bacterial community of 185 strains (SynCom) that mimics the root-associated microbiome of Arabidopsis. We found that a dose of 3.6 × 10−6 g acid equivalent/liter (low dose of glyphosate, or LDG) produced an ∼14% increase in the shoot dry weight (i.e., hormesis) of uninoculated plants. Unexpectedly, in plants inoculated with the SynCom, LDG reduced shoot dry weight by ∼17%. We found that LDG enriched two Firmicutes and two Burkholderia strains in the roots. These specific strains are known to act as root growth inhibitors (RGI) in monoassociation assays. We tested the link between RGI and shoot dry weight reduction in LDG by assembling a new synthetic community lacking RGI strains. Dropping RGI strains out of the community restored growth induction by LDG. Finally, we showed that individual RGI strains from a few specific phyla were sufficient to switch the response to LDG from growth promotion to growth inhibition. Our results indicate that glyphosate hormesis was completely dependent on the root microbiome composition, specifically on the presence of root growth inhibitor strains. IMPORTANCE Since the introduction of glyphosate-resistant crops, glyphosate has become the most common and widely used herbicide around the world. Due to its intensive use and ability to bind to soil particles, it can be found at low concentrations in the environment. The effect of these remnants of glyphosate in plants has not been broadly studied; however, glyphosate 1,000 to 100,000 times less concentrated than the recommended field dose promoted growth in several species in laboratory and greenhouse experiments. However, this effect is rarely observed in agricultural fields, where complex communities of microbes have a central role in the way plants respond to external cues. Our study reveals how root-associated bacteria modulate the responses of Arabidopsis to low doses of glyphosate, shifting between growth promotion and growth inhibition.


Author(s):  
Rajiv Pathak ◽  
Vipassana Paudel ◽  
Anupama Shrestha ◽  
Janardan Lamichhane ◽  
Dhurva. P. Gauchan

Phosphorous (P) is an essential macronutrient and most soils contain high levels of P. However, its availability to plant is limited by rapid immobilization of phosphorous compounds to insoluble forms and hence plant available forms of P in soils are found in low amounts. Phosphate solubilizing bacteria provide an eco-friendly alternative to convert insoluble phosphates into plant available forms. In the present study, three phosphate solubilizing bacterial isolates (PB-1, PB-4 and VC-01) with visually significant phosphate solubilizing abilities were isolated from tomato rhizosphere soil. In-vitro study in pikovskaya’s agar revealed that isolate PB-1 had the highest phosphate solubilizing ability with a phosphate solubilizing index of 2.08±0.07 followed by isolate VC-01 (1.31±0.09) and PB-4 (1.24±0.08). Isolates were used as bacterial inoculum to assess their ability to promote tomato (Lycopersicon esculentum var. Srijana) seedling and plant growth in in-vitro and greenhouse experiment respectively. Isolate PB-4 showed best growth promotion in seedling assay whereas isolate PB-1 and VC-01 also promoted seedling growth compared to control. In greenhouse experiment however, isolates VC-01 and PB-1 significantly enhanced all parameters (shoot length, root length, shoot and root dry weight) compared to uninoculated control whereas isolate PB-4 had a positive effect on all parameters except root length.Kathmandu University Journal of Science, Engineering and TechnologyVol. 13, No. 2, 2017, page: 61-70


Plants ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 120 ◽  
Author(s):  
Mohammad K. Hassan ◽  
John A. McInroy ◽  
Jarrod Jones ◽  
Deepak Shantharaj ◽  
Mark R. Liles ◽  
...  

Plant growth-promoting rhizobacteria (PGPR) are increasingly used in crops worldwide. While selected PGPR strains can reproducibly promote plant growth under controlled greenhouse conditions, their efficacy in the field is often more variable. Our overall aim was to determine if pectin or orange peel (OP) amendments to Bacillus velezensis (Bv) PGPR strains could increase soybean growth and nodulation by Bradyrhizobium japonicum in greenhouse and field experiments to reduce variability. The treatments included untreated soybean seeds planted in field soil that contained Bv PGPR strains and non-inoculated controls with and without 0.1% (w/v) pectin or (1 or 10 mg/200 μL) orange peel (OP) amendment. In greenhouse and field tests, 35 and 55 days after planting (DAP), the plants were removed from pots, washed, and analyzed for treatment effects. In greenhouse trials, the rhizobial inoculant was not added with Bv strains and pectin or OP amendment, but in the field trial, a commercial B. japonicum inoculant was used with Bv strains and pectin amendment. In the greenhouse tests, soybean seeds inoculated with Bv AP193 and pectin had significantly increased soybean shoot length, dry weight, and nodulation by indigenous Bradyrhizobium compared to AP193 without pectin. In the field trial, pectin with Bv AP193 significantly increased the shoot length, dry weight, and nodulation of a commercial Bradyrhizobium japonicum compared to Bv AP193 without pectin. In greenhouse tests, OP amendment with AP193 at 10 mg significantly increased the dry weight of shoots and roots compared to AP193 without OP amendment. The results demonstrate that pectin-rich amendments can enhance Bv-mediated soybean growth promotion and nodulation by indigenous and inoculated B. japonicum.


2013 ◽  
Vol 59 (8) ◽  
pp. 534-539 ◽  
Author(s):  
Subramaniam Gopalakrishnan ◽  
Srinivas Vadlamudi ◽  
Shravya Apparla ◽  
Prakash Bandikinda ◽  
Rajendran Vijayabharathi ◽  
...  

Five strains of Streptomyces (CAI-17, CAI-68, CAI-78, KAI-26, and KAI-27) were previously reported to have potential for charcoal rot control and plant growth promotion (PGP) in sorghum. In this study, those 5 Streptomyces strains were characterized for their enzymatic activities and evaluated for their PGP capabilities on rice. All the Streptomyces strains were able to produce lipase and β-1,3-glucanase; grew in NaCl (up to 8%), at pH 5–13, and at temperatures 20–40 °C; and were resistant to ampicillin, sensitive to nalidixic acid, and highly sensitive to chloramphenicol, kanamycin, streptomycin, and tetracycline. They were highly tolerant to the fungicide bavistin but were highly sensitive to benlate, benomyl, and radonil. When evaluated on rice in the field, Streptomyces significantly enhanced tiller and panicle numbers, stover and grain yields, dry matter, root length, volume and dry weight, compared with the control. In the rhizosphere at harvest, microbial biomass carbon and nitrogen, dehydrogenase activity, total nitrogen, available phosphorus, and % organic carbon were also found significantly higher in Streptomyces-treated plots than in the control plots. This study further confirms that the selected Streptomyces have PGP activities.


Sign in / Sign up

Export Citation Format

Share Document