Phytostabilization of Polluted Military Soil Supported by Bioaugmentation with PGP-Trace Element Tolerant Bacteria Isolated from Helianthus petiolaris

Lead (Pb) and cadmium (Cd) are major environmental pollutants, and the accumulation of these elements in soils and plants is of great concern in agricultural production due to their toxic effects on crop growth. Also, these elements can enter into the food chain and severely affect human and animal health. Bioaugmentation with plant growth-promoting bacteria (PGPB) can contribute to an environmentally friendly and effective remediation approach by improving plant survival and promoting element phytostabilization or extraction under such harsh conditions. We isolated and characterised Pb and Cd-tolerant root-associated bacteria from Helianthus petiolaris growing on a Pb/Cd polluted soil in order to compose inoculants that can promote plant growth and also ameliorate the phytostabilization or phytoextraction efficiency. One hundred and five trace element-tolerant rhizospheric and endophytic bacterial strains belonging to eight different genera were isolated from the aromatic plant species Helianthus petiolaris. Most of the strains showed multiple PGP-capabilities, ability to immobilise trace elements on their cell wall, and promotion of seed germination. Bacillus paramycoides ST9, Bacillus wiedmannii ST29, Bacillus proteolyticus ST89, Brevibacterium frigoritolerans ST30, Cellulosimicrobium cellulans ST54 and Methylobacterium sp. ST85 were selected to perform bioaugmentation assays in greenhouse microcosms. After 2 months, seedlings of sunflower (H. annuus) grown on polluted soil and inoculated with B. proteolyticus ST89 produced 40% more biomass compared to the non-inoculated control plants and accumulated 20 % less Pb and 40% less Cd in the aboveground plant parts. In contrast, B. paramycoides ST9 increased the bioaccumulation factor (BAF) of Pb three times and of Cd six times without inhibiting plant growth. Our results indicate that, depending on the strain, bioaugmentation with specific beneficial bacteria can improve plant growth and either reduce trace element mobility or enhance plant trace element uptake.

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Role of Two Plant Growth-Promoting Bacteria in Remediating Cadmium-Contaminated Soil Combined with Miscanthus floridulus (Lab.)

Plants ◽

10.3390/plants10050912 ◽

2021 ◽

Vol 10 (5) ◽

pp. 912

Author(s):

Shuming Liu ◽

Hongmei Liu ◽

Rui Chen ◽

Yong Ma ◽

Bo Yang ◽

...

Keyword(s):

Plant Growth ◽

Contaminated Soils ◽

Translocation Factor ◽

Plant Growth Promoting Bacteria ◽

Bacterial Strains ◽

Pgp Traits ◽

Cd Tolerance ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Cd Translocation

Miscanthus spp. are energy plants and excellent candidates for phytoremediation approaches of metal(loid)s-contaminated soils, especially when combined with plant growth-promoting bacteria. Forty-one bacterial strains were isolated from the rhizosphere soils and roots tissue of five dominant plants (Artemisia argyi Levl., Gladiolus gandavensis Vaniot Houtt, Boehmeria nivea L., Veronica didyma Tenore, and Miscanthus floridulus Lab.) colonizing a cadmium (Cd)-contaminated mining area (Huayuan, Hunan, China). We subsequently tested their plant growth-promoting (PGP) traits (e.g., production of indole-3-acetic acid, siderophore, and 1-aminocyclopropane-1-carboxylate deaminase) and Cd tolerance. Among bacteria, two strains, Klebsiella michiganensis TS8 and Lelliottia jeotgali MR2, presented higher Cd tolerance and showed the best results regarding in vitro growth-promoting traits. In the subsequent pot experiments using soil spiked with 10 mg Cd·kg−1, we investigated the effects of TS8 and MR2 strains on soil Cd phytoremediation when combined with M. floridulus (Lab.). After sixty days of planting M. floridulus (Lab.), we found that TS8 increased plant height by 39.9%, dry weight of leaves by 99.1%, and the total Cd in the rhizosphere soil was reduced by 49.2%. Although MR2 had no significant effects on the efficiency of phytoremediation, it significantly enhanced the Cd translocation from the root to the aboveground tissues (translocation factor > 1). The combination of K. michiganensis TS8 and M. floridulus (Lab.) may be an effective method to remediate Cd-contaminated soils, while the inoculation of L. jeotgali MR2 may be used to enhance the phytoextraction potential of M. floridulus.

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The Effects of Plant Growth-Promoting Bacteria with Biostimulant Features on the Growth of a Local Onion Cultivar and a Commercial Zucchini Variety

Agronomy ◽

10.3390/agronomy11050888 ◽

2021 ◽

Vol 11 (5) ◽

pp. 888

Author(s):

Giorgia Novello ◽

Patrizia Cesaro ◽

Elisa Bona ◽

Nadia Massa ◽

Fabio Gosetti ◽

...

Keyword(s):

Plant Growth ◽

Growth Promotion ◽

Global Market ◽

Plant Growth Promoting Bacteria ◽

Bacterial Strains ◽

Mineral Concentration ◽

Positive Effects ◽

Plant Growth Promoting ◽

Onion Cultivar ◽

Growth Promoting

The reduction of chemical inputs due to fertilizer and pesticide applications is a target shared both by farmers and consumers in order to minimize the side effects for human and environmental health. Among the possible strategies, the use of biostimulants has become increasingly important as demonstrated by the fast growth of their global market and by the increased rate of registration of new products. In this work, we assessed the effects of five bacterial strains (Pseudomonas fluorescens Pf4, P. putida S1Pf1, P. protegens Pf7, P. migulae 8R6, and Pseudomonas sp. 5Vm1K), which were chosen according to their previously reported plant growth promotion traits and their positive effects on fruit/seed nutrient contents, on a local onion cultivar and on zucchini. The possible variations induced by the inoculation with the bacterial strains on the onion nutritional components were also evaluated. Inoculation resulted in significant growth stimulation and improvement of the mineral concentration of the onion bulb, induced particularly by 5Vm1K and S1Pf1, and in different effects on the flowering of the zucchini plants according to the bacterial strain. The present study provides new information regarding the activity of the five plant growth-promoting bacteria (PGPB) strains on onion and zucchini, two plant species rarely considered by the scientific literature despite their economic relevance.

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Growth response of wheat cultivars to bacterial inoculation in calcareous soil

Plant Soil and Environment ◽

10.17221/75/2010-pse ◽

2010 ◽

Vol 56 (No. 12) ◽

pp. 570-573 ◽

Cited By ~ 14

Author(s):

D. Egamberdieva

Keyword(s):

Plant Growth ◽

Calcareous Soil ◽

Dry Weight ◽

Plant Growth Promoting Bacteria ◽

Wheat Cultivars ◽

Bacterial Strains ◽

Bacterial Inoculation ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Selection Of

In this study the plant growth-promoting bacteria were analysed for their growth-stimulating effects on two wheat cultivars. The investigations were carried out in pot experiments using calcareous soil. The results showed that bacterial strains Pseudomonas spp. NUU1 and P. fluorescens NUU2 were able to colonize the rhizosphere of both wheat cultivars. Their plant growth-stimulating abilities were affected by wheat cultivars. The bacterial strains Pseudomonas sp. NUU1 and P. fluorescens NUU2 significantly stimulated the shoot and root length and dry weight of wheat cv. Turon, whereas cv. Residence was less affected by bacterial inoculation. The results of our study suggest that inoculation of wheat with Pseudomonas strains can improve plant growth in calcareous soil and it depends upon wheat cultivars. Prior to a selection of good bacterial inoculants, it is recommended to select cultivars that benefit from association with these bacteria.

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Two bacterial strains isolated from a Zn-polluted soil enhance plant growth and mycorrhizal efficiency under Zn-toxicity

Chemosphere ◽

10.1016/j.chemosphere.2005.06.053 ◽

2006 ◽

Vol 62 (9) ◽

pp. 1523-1533 ◽

Cited By ~ 131

Author(s):

A. Vivas ◽

B. Biró ◽

J.M. Ruíz-Lozano ◽

J.M. Barea ◽

R. Azcón

Keyword(s):

Plant Growth ◽

Polluted Soil ◽

Bacterial Strains ◽

Zn Toxicity

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Micro-remediation of chromium contaminated soils

PeerJ ◽

10.7717/peerj.6076 ◽

2018 ◽

Vol 6 ◽

pp. e6076 ◽

Cited By ~ 7

Author(s):

Hadia -e- Fatima ◽

Ambreen Ahmed

Keyword(s):

Plant Growth ◽

Contaminated Soils ◽

Crop Production ◽

Lens Culinaris ◽

Production Plant ◽

Plant Growth Promoting Bacteria ◽

Bacterial Strains ◽

Soil Release ◽

Plant Growth Promoting ◽

Growth Promoting

Bacteria are tiny organisms which are ubiquitously found in the environment. These microscopic living bodies are responsible for the flow of nutrients in biogeochemical cycles and fertility imparted to the soil. Release of excessive chromium in agricultural soils due to rapid growth of industries may result in minimizing the fertility of soil in future, which will lead to reduction in crop production. Plant growth promoting bacteria (PGPB) are beneficial to the environment, some of which can tolerate chromium and protect plants against heavy metal stress. The current study aims to identify such chromium-tolerant auxin-producing rhizobacteria and to investigate their inoculation effects on the growth characteristics of Lens culinaris in chromium polluted soils by using two different chromium salts i.e., K2Cr2O7 and K2CrO4 in varying concentrations (0, 50, 100, 200, 400 and 500 µgml−1). The results revealed that Bacillus species are efficient in significantly reducing the deleterious effects of Cr. These effective bacterial strains were able to stimulate the growth of metal effected plants of Lens culinaris which were grown in chromium contaminated environment. Therefore, these plant growth promoting rhizobacteria PGPRs, having both auxin production potential and chromium-resistance ability, are considered as efficient micro-factories against chromium pollution.

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Plant growth promotion of barley (Hordeum vulgare L.) by potassium solubilizing bacteria with multifarious plant growth promoting attributes

Plant Science Today ◽

10.14719/pst.1377 ◽

2021 ◽

Vol 8 (sp1) ◽

pp. 17-24

Author(s):

Tanvir Kaur ◽

Rubee Devi ◽

Divjot Kour ◽

Ashok Yadav ◽

Ajar Nath Yadav

Keyword(s):

Plant Growth ◽

Environmental Sustainability ◽

Growth Promotion ◽

Growth Parameters ◽

Sugar Content ◽

Plant Growth Promoting Bacteria ◽

Bacterial Strains ◽

Hordeum Vulgare L ◽

Plant Growth Promoting ◽

Growth Promoting

Potassium (K) is the foremost macronutrients for growth of plant, soil health and fertility. The huge application of NPK chemical fertilizers negatively impacts the economy and is a threat to environmental sustainability. The rapid depletion of K mineral in soil is due to the application of agrochemicals agricultural fields for the production of crops in India. In present investigation, K-solubilizing microbes (KSM) were isolated and enumerated from cereal crops growing in Sirmour Himachal Pradesh. A total 125 bacteria were isolated and screened for K- solubilization on Aleksandrov agar plates and found that 31 bacterial strains exhibited K-solubilization. These 31 K-solubilizing strains of bacteria were additionally screened for other plant growth promoting (PGP) potential including solubilization of minerals, production of siderophores, ammonia, hydrogen cyanide and indole acetic acids. The performance of an efficient K-solubilizer was evaluated for plant growth promoting ability in pot assay under in vitro conditions. The strain EU-LWNA-25 positively influenced shoot length, fresh weight, carotenoids and total sugar content than the full dose, half dose and control. The strain enhancing physiological and growth parameters was identified by BLASTn analysis as Pseudomonas gessardii EU-LWNA-25. K-solubilizing plant growth promoting bacteria could be suitable bioinoculants for Rabi seasonal crops and overcomes the challenges of sustainable agriculture in K-deficient soil.

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Influence of bacterial strains isolated from lead-polluted soil and their interactions with arbuscular mycorrhizae on the growth of Trifolium pratense L. under lead toxicity

Canadian Journal of Microbiology ◽

10.1139/w03-073 ◽

2003 ◽

Vol 49 (10) ◽

pp. 577-588 ◽

Cited By ~ 80

Author(s):

A Vivas ◽

R Azcón ◽

B Biró ◽

J M Barea ◽

J M Ruiz-Lozano

Keyword(s):

Plant Growth ◽

Mycorrhizal Fungi ◽

Trifolium Pratense ◽

Arbuscular Mycorrhizal ◽

Polluted Soil ◽

Bacterial Strains ◽

Spiked Soil ◽

Plant Growth Promoting ◽

Trifolium Pratense L ◽

Growth Promoting

We isolated two bacterial strains from an experimentally lead (Pb)-polluted soil in Hungary, 10 years after soil contamination. These strains represented the two most abundant cultivable bacterial groups in such soil, and we tested their influence on Trifolium pratense L. growth and on the functioning of native mycorrhizal fungi under Pb toxicity in a second Pb-spiked soil. Our results showed that bacterial strain A enhanced plant growth, nitrogen and phosphorus accumulations, nodule formation, and mycorrhizal infection, demonstrating its plant-growth-promoting activity. In addition, strain A decreased the amount of Pb absorbed by plants, when expressed on a root weight basis, because of increased root biomass due to the production of indoleacetic acid. The positive effect of strain A was not only evident after a single inoculation but also in dual inoculation with arbuscular mycorrhizal fungi. Strain A also exhibited higher tolerance than strain B when cultivated under increasing Pb levels in the spiked soil. Molecular identification unambiguously placed strain A within the genus Brevibacillus. We showed that it is important to select the most tolerant and efficient bacterial strain for co-inoculation with arbuscular mycorrhizal fungi to promote effective symbiosis and thus stimulate plant growth under adverse environmental conditions, such as heavy-metal contamination.Key words: arbuscular mycorrhizal symbiosis, Pb-polluted soil, plant-growth-promoting bacteria.

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Long-term effect of inoculating lodgepole pine seedlings with plant growth-promoting bacteria originating from disturbed gravel mining ecosystem

Canadian Journal of Forest Research ◽

10.1139/cjfr-2020-0333 ◽

2020 ◽

Author(s):

Kiran Preet Padda ◽

Akshit Puri ◽

Christopher Chanway

Keyword(s):

Plant Growth ◽

Lodgepole Pine ◽

Tree Regeneration ◽

Lytic Enzyme ◽

Plant Growth Promoting Bacteria ◽

Bacterial Strains ◽

Acetic Acid Production ◽

Gravel Mining ◽

Pine Seedlings ◽

Pine Trees

Gravel mining is prevalent in forest landscapes of Canada, typically resulting in complete loss of vegetation and topsoil. Despite such extreme disturbance, lodgepole pine (Pinus contorta var. latifolia) trees are thriving at unreclaimed gravel pits located in central-interior British Columbia, possibly due, at least in part, to the association of pine trees with their endophytic bacteria. Testing this possibility, several bacterial strains were previously isolated from pine trees growing at these pits, of which 14 were identified as effective nitrogen-fixers. In this study, we evaluated the inoculation effect of these 14 strains on lodgepole pine growth under nitrogen-poor conditions. Each strain colonized the rhizosphere and internal tissues of pine seedlings and significantly enhanced their length (24–65%) and biomass (100–300%), 18 months after sowing and inoculation. Notably, three Pseudomonas strains increased pine seedling length by 1.6-fold and biomass by 4-fold. Most strains also demonstrated substantial potential to promote plant growth via phosphorus solubilization, siderophore production, 1-aminocyclopropane-1-carboxylic acid deaminase activity, indole-3-acetic acid production, lytic enzyme activity and catalase activity. Our results suggest that such effective bacteria could be sustaining pine growth on bare gravel, indicating a possible ecological association that may explain natural tree regeneration in such a disturbed ecosystem.

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Plant growth-promoting bacteria that decrease heavy metal toxicity in plants

Canadian Journal of Microbiology ◽

10.1139/w99-143 ◽

2000 ◽

Vol 46 (3) ◽

pp. 237-245 ◽

Cited By ~ 507

Author(s):

Genrich I Burd ◽

D George Dixon ◽

Bernard R Glick

Keyword(s):

Heavy Metal ◽

Plant Growth ◽

Indian Mustard ◽

Dry Weight ◽

Plant Growth Promoting Bacteria ◽

Bacterial Strains ◽

Plant Growth Promoting ◽

High Concentrations ◽

Kluyvera Ascorbata ◽

Nickel Lead

Kluyvera ascorbata SUD165 and a siderophore-overproducing mutant of this bacterium, K. ascorbata SUD165/26, were used to inoculate tomato, canola, and Indian mustard seeds which were then grown in soil for 25-42 days in the presence of either nickel, lead, or zinc. The parameters that were monitored included plant wet and dry weight, protein and chlorophyll content in the plant leaves, and concentration of heavy metal in the plant roots and shoots. As indicated by a decrease in the measured values of these parameters, in all instances, plant growth was inhibited by the presence of the added metal. Both bacterial strains were effective, although not always to a statistically significant extent, at relieving a portion of the growth inhibition caused by the metals. In most cases, the siderophore overproducing mutant K. ascorbata 165/26 exerted a more pronounced effect on plant growth than did the wild-type bacterium K. ascorbata SUD165. The data suggest that the ability of these bacteria to protect plants against the inhibitory effects of high concentrations of nickel, lead, and zinc is related to the bacteria providing the plants with sufficient iron.Key words: phytoremediation, heavy metals, siderophores, Kluyvera ascorbata.

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Glyphosate Degradation by Two Plant Growth Promoting Bacteria (PGPB) Isolated from Rhizosphere of Maize

Microbiology Research Journal International ◽

10.9734/mrji/2018/v26i630081 ◽

2019 ◽

pp. 1-11 ◽

Cited By ~ 1

Author(s):

E. Ezaka ◽

A. K. Akintokun ◽

P. O. Akintokun ◽

L. B. Taiwo ◽

A. C. O. Uthman ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Plant Growth ◽

Bacillus Cereus ◽

Mixed Culture ◽

Degradation Products ◽

Polluted Soil ◽

Plant Growth Promoting Bacteria ◽

Plant Growth Promoting ◽

Growth Promoting ◽

And Control

This study was aimed at evaluating the possible utilization of glyphosate tolerant plant growth promoting bacteria (Pseudomonas aeruginosa and Bacillus cereus) for bioremediation of glyphosate polluted soil. The soil samples were spiked with 3.1 mg/ml, 7.2 mg/ml and 14.4 mg/ml of glyphosate and then inoculated with Pseudomonas aeruginosa and Bacillus cereus, level of glyphosate pollution before and after inoculation with the bacteria were determined using Gas Chromatography-Mass Spectroscopy (GC-MS) after extraction with acetonitrile. The bacteria showed significant ability to degrade glyphosate. Pseudomonas aeruginosa, Bacillus cereus, their mixed culture and control recorded percentage degradation of 76.11, 85.8, 75.8 and 49%, respectively at 3.1 mg/ml of glyphosate while At the concentration of 7.2 mg/ml, the percentage degradation by P. aeruginosa, Bacillus cereus, mixed culture of the isolates and control was 84.9, 72.7, 66.4% and 39.2%, respectively. The isolates also showed significant rate of degradation at the concentration of 14.4 mg/ml. The GC-MS results showed a significant variation in the degradation products obtained when compared with control. This study revealed that substantial amount of glyphosate was degraded by P. aeruginosa and Bacillus cereus. Hence, they may have great potential in bioremediation of glyphosate polluted soil.

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