Potential for Plant Growth Promotion of Rhizobacteria Associated withSalicorniaGrowing in Tunisian Hypersaline Soils

Soil salinity and drought are among the environmental stresses that most severely affect plant growth and production around the world. In this study the rhizospheres ofSalicorniaplants and bulk soils were collected fromSebkhetandChotthypersaline ecosystems in Tunisia. Depiction of bacterial microbiome composition by Denaturing Gradient Gel Electrophoresis unveiled the occurrence of a high bacterial diversity associated withSalicorniaroot system. A large collection of 475 halophilic and halotolerant bacteria was established fromSalicorniarhizosphere and the surrounding bulk soil, and the bacteria were characterized for the resistance to temperature, osmotic and saline stresses, and plant growth promotion (PGP) features. TwentyHalomonasstrains showed resistance to a wide set of abiotic stresses and were able to perform different PGP activitiesin vitroat 5% NaCl, including ammonia and indole-3-acetic acid production, phosphate solubilisation, and potential nitrogen fixation. By using agfp-labelled strain it was possible to demonstrate thatHalomonasis capable of successfully colonisingSalicorniaroots in the laboratory conditions. Our results indicated that the culturable halophilic/halotolerant bacteria inhabiting salty and arid ecosystems have a potential to contribute to promoting plant growth under the harsh salinity and drought conditions. These halophilic/halotolerant strains could be exploited in biofertilizer formulates to sustain crop production in degraded and arid lands.

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The Root Microbiome of Salicornia ramosissima as a Seedbank for Plant-Growth Promoting Halotolerant Bacteria

Applied Sciences ◽

10.3390/app11052233 ◽

2021 ◽

Vol 11 (5) ◽

pp. 2233

Author(s):

Maria J. Ferreira ◽

Angela Cunha ◽

Sandro Figueiredo ◽

Pedro Faustino ◽

Carla Patinha ◽

...

Keyword(s):

Plant Growth ◽

Plant Growth Promotion ◽

Growth Promotion ◽

Cultivated Plants ◽

Plant Growth Promoting Bacteria ◽

Crop Cultivation ◽

Halotolerant Bacteria ◽

Salicornia Ramosissima ◽

Plant Growth Promoting ◽

Growth Promoting

Root−associated microbial communities play important roles in the process of adaptation of plant hosts to environment stressors, and in this perspective, the microbiome of halophytes represents a valuable model for understanding the contribution of microorganisms to plant tolerance to salt. Although considered as the most promising halophyte candidate to crop cultivation, Salicornia ramosissima is one of the least-studied species in terms of microbiome composition and the effect of sediment properties on the diversity of plant-growth promoting bacteria associated with the roots. In this work, we aimed at isolating and characterizing halotolerant bacteria associated with the rhizosphere and root tissues of S. ramosissima, envisaging their application in saline agriculture. Endophytic and rhizosphere bacteria were isolated from wild and crop cultivated plants, growing in different estuarine conditions. Isolates were identified based on 16S rRNA sequences and screened for plant-growth promotion traits. The subsets of isolates from different sampling sites were very different in terms of composition but consistent in terms of the plant-growth promoting traits represented. Bacillus was the most represented genus and expressed the wider range of extracellular enzymatic activities. Halotolerant strains of Salinicola, Pseudomonas, Oceanobacillus, Halomonas, Providencia, Bacillus, Psychrobacter and Brevibacterium also exhibited several plant-growth promotion traits (e.g., 3-indole acetic acid (IAA), 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase, siderophores, phosphate solubilization). Considering the taxonomic diversity and the plant-growth promotion potential of the isolates, the collection represents a valuable resource that can be used to optimize the crop cultivation of Salicornia under different environmental conditions and for the attenuation of salt stress in non-halophytes, considering the global threat of arable soil salinization.

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EFFICACY OF RHIZOBACTERIA ON PLANT GROWTH PROMOTION AND DISEASE SUPPRESSION IN VITRO

Acta Horticulturae ◽

10.17660/actahortic.2012.961.69 ◽

2012 ◽

pp. 525-532 ◽

Cited By ~ 1

Author(s):

S. Velivelli ◽

E. O'Herlihy ◽

B. Janczura ◽

B. Doyle Prestwich ◽

J. Ghyselinck ◽

...

Keyword(s):

Plant Growth ◽

Plant Growth Promotion ◽

Growth Promotion ◽

Disease Suppression

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Exploitation of endophytic Pseudomonas sp. for plant growth promotion and colonization in rice

Journal of Applied and Natural Science ◽

10.31018/jans.v9i3.1359 ◽

2017 ◽

Vol 9 (3) ◽

pp. 1310-1316

Author(s):

Gurjot Kaur ◽

Poonam Sharma ◽

Deepika Chhabra ◽

Kailash Chand ◽

Gurjit Singh Mangat

Keyword(s):

Plant Growth ◽

Plant Growth Promotion ◽

Growth Promotion ◽

Acc Deaminase ◽

Pseudomonas Sp ◽

Bacterial Isolates ◽

Pgp Traits ◽

P Solubilization ◽

Fluorescent Pigment

The present investigation was carried out to exploit bacterial endophytes associated with root and leaf tissue of rice plant for plant growth promotion (PGP) and colonization study in vitro. Total 10 endophytic bacterial isolates (Pseudomonas sp.) were evaluate for PGP traits like P solubilization, production of Indole acetic acid (IAA), siderophore, ACC deaminase, protease, cellulase, fluorescent pigment, urease and denitrification activity. Out of 10 endophytic bacteria 30 %, 60 %, 20 %, 70 %, 10 % and 10 % were positive for siderophore, protease, cellulase, fluorescent pigment, urease and denitrification respectively. Maximum IAA production was recorded with isolate LRBLE7 (18.8 μgml-1) followed by LRBRE4 (16.0 μgml-1) and maximum P-solubilization was recorded with isolate LRBRE4 (5.8 mg 100 ml-1) followed by LRBLE7 (4.4 mg 100 ml-1). ACC deaminase production was recorded with isolate LRBLE6 (O.D=0.352 nm) followed by LRBRE5 (O.D=0.324nm). Three potential isolates (LRBRE4, LRBRE6 and LRBLE7) were selected on the basis of multiple PGP traits and were subjected to colonization study of rice seedling in vitro. Potential bacterial isolates can be exploited for improving growth and productivity in rice under sustainable management system.

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Combined effects of rhizo-competitive rhizosphere and non-rhizosphere Bacillus in plant growth promotion and yield improvement of Eleusine coracana (Ragi)

Canadian Journal of Microbiology ◽

10.1139/cjm-2019-0103 ◽

2020 ◽

Vol 66 (2) ◽

pp. 111-124 ◽

Cited By ~ 1

Author(s):

Shrivardhan Dheeman ◽

Nitin Baliyan ◽

Ramesh Chandra Dubey ◽

Dinesh Kumar Maheshwari ◽

Sandeep Kumar ◽

...

Keyword(s):

Plant Growth ◽

Plant Growth Promotion ◽

Crop Production ◽

Growth Promotion ◽

Soil Analysis ◽

Crop Protection ◽

Sclerotium Rolfsii ◽

Eleusine Coracana ◽

Soil Reclamation ◽

Yield Improvement

This study emphasizes the beneficial role of rhizo-competitive Bacillus spp. isolated from rhizospheric and non-rhizospheric soil in plant growth promotion and yield improvement via nitrogen fixation and biocontrol of Sclerotium rolfsii causing foot rot disease in Eleusine coracana (Ragi). The selection of potent rhizobacteria was based on plant-growth-promoting attributes using Venn set diagram and Bonitur scale. Bacillus pumilus MSTA8 and Bacillus amyloliquefaciens MSTD26 were selected because they were effective in root colonization, rhizosphere competence, and biofilm formation using root exudates of E. coracana L. rich with carbohydrates, proteins, and amino acids. The relative chemotaxis index of the isolates expressed the invasive behavior of the rhizosphere. During pot and field trials, the consortium of the rhizobacteria in a vermiculite carrier increased the grain yield by 37.87%, with a significant harvest index of 16.45. Soil analysis after the field trial revealed soil reclamation potentials to manage soil nutrition and fertility. Both indexes ensured crop protection and production in eco-safe ways and herald commercialization of Bacillus bio-inoculant for improvement in crop production and disease management of E. coracana.

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Plant growth promotion in cereal and leguminous agricultural important plants: From microorganism capacities to crop production

Microbiological Research ◽

10.1016/j.micres.2013.09.011 ◽

2014 ◽

Vol 169 (5-6) ◽

pp. 325-336 ◽

Cited By ~ 231

Author(s):

F. Pérez-Montaño ◽

C. Alías-Villegas ◽

R.A. Bellogín ◽

P. del Cerro ◽

M.R. Espuny ◽

...

Keyword(s):

Plant Growth ◽

Plant Growth Promotion ◽

Crop Production ◽

Growth Promotion

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Isolation, Biochemical and Genomic Characterization of Glyphosate Tolerant Bacteria to Perform Microbe-Assisted Phytoremediation

Frontiers in Microbiology ◽

10.3389/fmicb.2020.598507 ◽

2021 ◽

Vol 11 ◽

Author(s):

Francisco Massot ◽

Panagiotis Gkorezis ◽

Jonathan Van Hamme ◽

Damian Marino ◽

Bojana Spirovic Trifunovic ◽

...

Keyword(s):

Plant Growth ◽

Plant Growth Promotion ◽

Large Scale ◽

Agricultural Soils ◽

Growth Promotion ◽

Sole Source ◽

Bacterial Strains ◽

Positive Effects ◽

Assisted Phytoremediation

The large-scale use of the herbicide glyphosate leads to growing ecotoxicological and human health concerns. Microbe-assisted phytoremediation arises as a good option to remove, contain, or degrade glyphosate from soils and waterbodies, and thus avoid further spreading to non-target areas. To achieve this, availability of plant-colonizing, glyphosate-tolerant and -degrading strains is required and at the same time, it must be linked to plant-microorganism interaction studies focusing on a substantive ability to colonize the roots and degrade or transform the herbicide. In this work, we isolated bacteria from a chronically glyphosate-exposed site in Argentina, evaluated their glyphosate tolerance using the minimum inhibitory concentration assay, their in vitro degradation potential, their plant growth-promotion traits, and performed whole genome sequencing to gain insight into the application of a phytoremediation strategy to remediate glyphosate contaminated agronomic soils. Twenty-four soil and root-associated bacterial strains were isolated. Sixteen could grow using glyphosate as the sole source of phosphorous. As shown in MIC assay, some strains tolerated up to 10000 mg kg–1 of glyphosate. Most of them also demonstrated a diverse spectrum of in vitro plant growth-promotion traits, confirmed in their genome sequences. Two representative isolates were studied for their root colonization. An isolate of Ochrobactrum haematophilum exhibited different colonization patterns in the rhizoplane compared to an isolate of Rhizobium sp. Both strains were able to metabolize almost 50% of the original glyphosate concentration of 50 mg l–1 in 9 days. In a microcosms experiment with Lotus corniculatus L, O. haematophilum performed better than Rhizobium, with 97% of glyphosate transformed after 20 days. The results suggest that L. corniculatus in combination with to O. haematophilum can be adopted for phytoremediation of glyphosate on agricultural soils. An effective strategy is presented of linking the experimental data from the isolation of tolerant bacteria with performing plant-bacteria interaction tests to demonstrate positive effects on the removal of glyphosate from soils.

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Effects of Halophyte Root Exudates and Their Components on Chemotaxis, Biofilm Formation and Colonization of the Halophilic Bacterium Halomonas Anticariensis FP35T

Microorganisms ◽

10.3390/microorganisms8040575 ◽

2020 ◽

Vol 8 (4) ◽

pp. 575

Author(s):

Inmaculada Sampedro ◽

Daniel Pérez-Mendoza ◽

Laura Toral ◽

Esther Palacios ◽

César Arriagada ◽

...

Keyword(s):

Plant Growth ◽

Root Exudates ◽

Plant Growth Promotion ◽

Biofilm Formation ◽

Crop Production ◽

Positive Impact ◽

Growth Promotion ◽

Halophilic Bacteria ◽

Plant Growth Promoting Bacteria ◽

Positive Effects

Increase in soil salinity poses an enormous problem for agriculture and highlights the need for sustainable crop production solutions. Plant growth-promoting bacteria can be used to boost the growth of halophytes in saline soils. Salicornia is considered to be a promising salt-accumulating halophyte for capturing large amounts of carbon from the atmosphere. In addition, colonization and chemotaxis could play an important role in Salicornia-microbe interactions. In this study, the role of chemotaxis in the colonization of the halophilic siredophore-producing bacteria, Halomonas anticariensis FP35T, on Salicornia hispanica plants was investigated. The chemotactic response of FP35T to Salicornia root exudates showed optimum dependence at a salt concentration of 5 % NaCl (w/v). Oleanolic acid, the predominant compound in the exudates detected by HPLC and identified by UPLC-HRMS Q-TOF, acts as a chemoattractant. In vitro experiments demonstrated the enhanced positive effects of wild-type H. anticariensis strain FP35T on root length, shoot length, germination and the vigour index of S. hispanica. Furthermore, these positive effects partially depend on an active chemotaxis system, as the chemotaxis mutant H. anticariensis FP35 ΔcheA showed reduced plant growth promotion for all the parameters tested. Overall, our results suggest that chemotaxis responses to root exudates play an important role in interactions between Salicornia and halophilic bacteria, enhance their colonization and boost plant growth promotion. Preliminary results also indicate that root exudates have a positive impact on H. anticariensis FP35T biofilm formation under saline conditions, an effect which totally depends on the presence of the cheA gene.

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Isolation, Characterization, and Use for Plant Growth Promotion Under Salt Stress, of ACC Deaminase-Producing Halotolerant Bacteria Derived from Coastal Soil

Journal of Microbiology and Biotechnology ◽

10.4014/jmb.1007.07011 ◽

2010 ◽

Vol 20 (11) ◽

pp. 1577-1584 ◽

Cited By ~ 201

Author(s):

M. A. Siddikee

Keyword(s):

Salt Stress ◽

Plant Growth ◽

Plant Growth Promotion ◽

Growth Promotion ◽

Acc Deaminase ◽

Halotolerant Bacteria

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Isolation, selection, and characterization of beneficial rhizobacteria from pea, lentil, and chickpea grown in western Canada

Canadian Journal of Microbiology ◽

10.1139/w08-008 ◽

2008 ◽

Vol 54 (4) ◽

pp. 248-258 ◽

Cited By ~ 72

Author(s):

Russell K. Hynes ◽

Grant C.Y. Leung ◽

Danielle L.M. Hirkala ◽

Louise M. Nelson

Keyword(s):

Plant Growth ◽

Plant Growth Promotion ◽

Fungal Pathogens ◽

Crop Production ◽

Growth Promotion ◽

Profile Analysis ◽

Acc Deaminase ◽

Plant Growth Promoting ◽

Growth Promoting

The use of beneficial soil microorganisms as agricultural inputs for improved crop production requires selection of rhizosphere-competent microorganisms with plant growth-promoting attributes. A collection of 563 bacteria originating from the roots of pea, lentil, and chickpea grown in Saskatchewan was screened for several plant growth-promoting traits, for suppression of legume fungal pathogens, and for plant growth promotion. Siderophore production was detected in 427 isolates (76%), amino-cyclopropane-1-carboxylic acid (ACC) deaminase activity in 29 isolates (5%), and indole production in 38 isolates (7%). Twenty-six isolates (5%) suppressed the growth of Pythium sp. strain p88-p3, 40 isolates (7%) suppressed the growth of Fusarium avenaceum , and 53 isolates (9%) suppressed the growth of Rhizoctonia solani CKP7. Seventeen isolates (3%) promoted canola root elongation in a growth pouch assay, and of these, 4 isolates promoted the growth of lentil and one isolate promoted the growth of pea. Fatty acid profile analysis and 16S rRNA sequencing of smaller subsets of the isolates that were positive for the plant growth-promotion traits tested showed that 39%–42% were members of the Pseudomonadaceae and 36%–42% of the Enterobacteriaceae families. Several of these isolates may have potential for development as biofertilizers or biopesticides for western Canadian legume crops.

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