Investigation of Arsenic-Resistant, Arsenite-Oxidizing Bacteria for Plant Growth Promoting Traits Isolated From Arsenic Contaminated Soils

Abstract The menace of arsenic (As) pollution being severe warrants opting for low cost microbial remediation strategies. The present study of identifying suitable bacterial strains led to isolation of eleven As-tolerant strains from the As contaminated rhizosphere soils of West Bengal, India. They were found to oxidize/reduce 55%-31.6% of 5 mM As(III) and 73%-37.6% of 5 mM As(V) within 12 hrs. The four isolates (BcAl-1, JN 73, LAR-2 and AR-30) had high level of As(III) oxidase activity along with higher level of As(V) and As(III) resistance. The presence of aoxB gene was observed in these four As(III) oxidizing isolates. Evaluation of plant growth promoting characteristics revealed that BcAl-1 (Burkholderia cepacia), JN73 (Burkholderia metallica), AR-30 (Burkholderia cenocepacia) and LAR-2 (Burkholderia sp) had enormous plant growth-promoting characteristics (PGP), including ability to solubilize phosphate, siderophore production, indole acetic acid like molecules production, ACC deaminase production and nodule formation under As stressed condition. BcAl-1 and JN73 emerged as the most promising traits in As removal as well as plant growth promotion.

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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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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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Root-specific camalexin biosynthesis controls the plant growth-promoting effects of multiple bacterial strains

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1818604116 ◽

2019 ◽

Vol 116 (31) ◽

pp. 15735-15744 ◽

Cited By ~ 25

Author(s):

Anna Koprivova ◽

Stefan Schuck ◽

Richard P. Jacoby ◽

Irene Klinkhammer ◽

Bastian Welter ◽

...

Keyword(s):

Plant Growth ◽

Growth Promotion ◽

Bacterial Strains ◽

Natural Ecosystems ◽

Promoting Effect ◽

Gene Encoding ◽

A Genome ◽

Sulfatase Activity ◽

Plant Growth Promoting ◽

Growth Promoting

Plants in their natural ecosystems interact with numerous microorganisms, but how they influence their microbiota is still elusive. We observed that sulfatase activity in soil, which can be used as a measure of rhizosphere microbial activity, is differently affected by Arabidopsis accessions. Following a genome-wide association analysis of the variation in sulfatase activity we identified a candidate gene encoding an uncharacterized cytochrome P450, CYP71A27. Loss of this gene resulted in 2 different and independent microbiota-specific phenotypes: A lower sulfatase activity in the rhizosphere and a loss of plant growth-promoting effect by Pseudomonas sp. CH267. On the other hand, tolerance to leaf pathogens was not affected, which agreed with prevalent expression of CYP71A27 in the root vasculature. The phenotypes of cyp71A27 mutant were similar to those of cyp71A12 and cyp71A13, known mutants in synthesis of camalexin, a sulfur-containing indolic defense compound. Indeed, the cyp71A27 mutant accumulated less camalexin in the roots upon elicitation with silver nitrate or flagellin. Importantly, addition of camalexin complemented both the sulfatase activity and the loss of plant growth promotion by Pseudomonas sp. CH267. Two alleles of CYP71A27 were identified among Arabidopsis accessions, differing by a substitution of Glu373 by Gln, which correlated with the ability to induce camalexin synthesis and to gain fresh weight in response to Pseudomonas sp. CH267. Thus, CYP71A27 is an additional component in the camalexin synthesis pathway, contributing specifically to the control of plant microbe interactions in the root.

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Isolation and Molecular Characterization of a Model Antagonistic Pseudomonas aeruginosa Divulging In Vitro Plant Growth Promoting Characteristics

BioMed Research International ◽

10.1155/2018/6147380 ◽

2018 ◽

Vol 2018 ◽

pp. 1-7 ◽

Cited By ~ 9

Author(s):

Bushra Uzair ◽

Rehana Kausar ◽

Syeda Asma Bano ◽

Sammer Fatima ◽

Malik Badshah ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Plant Growth ◽

Growth Promotion ◽

Gene Bank ◽

Accession Number ◽

Bacterial Strains ◽

Rhizopus Microsporus ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Gene Bank Accession

The use of microbial technologies in agriculture is currently expanding quite rapidly with the identification of new bacterial strains, which are more effective in promoting plant growth. In the present study 18 strains of Pseudomonas were isolated from soil sample of Balochistan coastline. Among isolated Pseudomonas strains four designated as SP19, SP22, PS24, and SP25 exhibited biocontrol activities against phytopathogenic fungi, that is, Rhizopus microsporus, Fusarium oxysporum, Aspergillus niger, Alternaria alternata, and Penicillium digitatum; PS24 identified as Pseudomonas aeruginosa by 16srRNA gene bank accession number EU081518 was selected on the basis of its antifungal activity to explore its potential as plant growth promotion. PS24 showed multiple plant growth promoting attributes such as phosphate solubilization activity, indole acetic acid (IAA), siderophore, and HCN production. In order to determine the basis for antifungal properties, antibiotics were extracted from King B broth of PS24 and analyzed by TLC. Pyrrolnitrin antibiotic was detected in the culture of strain PS24. PS24 exhibited antifungal activities found to be positive for hydrogen cyanide synthase Hcn BC gene. Sequencing of gene of Hcn BC gene of strain PS24 revealed 99% homology with the Pseudomonas aeruginosa strain PA01. The sequence of PS24 had been submitted in gene bank accession number KR605499. Ps. aeruginosa PS24 with its multifunctional biocontrol possessions can be used to bioprotect the crop plants from phytopathogens.

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Isolation, Characterization, and Evaluation of Native Rhizobacterial Consortia Developed From the Rhizosphere of Rice Grown in Organic State Sikkim, India, and Their Effect on Plant Growth

Frontiers in Microbiology ◽

10.3389/fmicb.2021.713660 ◽

2021 ◽

Vol 12 ◽

Author(s):

Mingma Thundu Sherpa ◽

Laxuman Sharma ◽

Niladri Bag ◽

Sayak Das

Keyword(s):

Plant Growth ◽

Plant Pathogens ◽

Burkholderia Cenocepacia ◽

Growth And Yield ◽

Root Weight ◽

Bacterial Strains ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Large Cardamom

Eight rhizospheric bacteria were isolated from the organic paddy fields of Sikkim, India, and identified as Pseudomonas kribbensis KSB, Burkholderia cenocepacia SRD, Kosakonia oryzendophytica YMA7, Pseudomonas rhodesiae SRB, Bacillus sp. ARA, Paenibacillus polymyxa COW3, Bacillus aryabhattai PSB2, and Bacillus megaterium PSB1. They showed plant growth-promoting attributes in rice and have bio-control potential against phytopathogen Colletotrichum gloeosporioides of large cardamom (Amomum subulatum). Burkholderia cenocepacia SRD showed production of indole acetic acid and ammonia and solubilization of phosphate and potassium and also possessed nitrogen fixation potential. It showed antagonistic activity against two other plant pathogens of large cardamom, viz., Curvularia eragrostidis and Pestalotiopsis sp., under in vitro conditions. The liquid bacterial consortium was prepared using the bacterial strains SRB, PSB1, and COW3 (Consortia-1); PSB2, SRD, and COW3 (Consortia-2); and COW3, KSB, and YMA7 (Consortia-3) to increase the growth and yield of rice plants under organic farming conditions. Greenhouse and field studies showed that the Consortia-3 had the highest plant growth-promoting activity. Consortia-3 demonstrated better agronomic performance in terms of root length (9.5 cm),number of leaflets per plant (5.3), grains per panicle (110.6), test grain weight (27.4 g), dry root weight per plant (0.73 g), and total dry biomass per plant (8.26 g).

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Biocontrol of Macrophomina phaseolina (Tassi) Goid causing charcoal rot disease in Lycopersicon esculentum L. by using multi species bacterial consortia

Environment Conservation Journal ◽

10.36953/ecj.2021.22351 ◽

2021 ◽

Vol 22 (3) ◽

pp. 441-449

Author(s):

Pradeep Kumar ◽

Sandeep Kumar ◽

R.C. Dubey

Keyword(s):

Lycopersicon Esculentum ◽

Plant Growth ◽

Growth Promotion ◽

Macrophomina Phaseolina ◽

Growth And Yield ◽

Pseudomonas Sp ◽

Bacillus Sp ◽

Bacterial Strains ◽

Plant Growth Promoting ◽

Growth Promoting

Plant growth-promoting bacterial strains (LEP1-LEP31) were isolated from rhizosphere of Lycopersicon esculentum L. (Tomato) and screened for their plant growth promoting (PGP) activities. On the basis of morphological, physiological, biochemical, carbon source utilization and molecular characterization, these strains were identified as Pseudomonas sp., Azotobacter sp. and Bacillus sp. For antagonistic activities all the strains were subject to the chitinase activities by the development of clear halo around the inoculated bacterial spots when loaded on chitin (0.2%) supplemented mediumBased on pot and field trial results of individual strains and consortium application, it may be concluded that all the three strains i.e. Pseudomonas sp. LEP17, Azotobacter sp. strain LEP21 and Bacillus sp. strain LEP25 showed plant growth promoting effects. The growth promotion provided by these strains was apparently related to improve shoot and root development, which resulted in better nutrient uptake capability and suppression of plant pathogen. All these three strains were superior in this regard because they provided the best and most consistent effects on growth and yield of L. esculentum. All these strains Pseudomonas sp. LEP17, Azotobacter sp. strain LEP21, Bacillus sp. strain LEP25 and their consortium seems to be suitable for use as a plant growth promoting and improvement of growth and yield

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Evaluation of the PGPR Capacity of Four Bacterial Strains and Their Mixtures, Tested on Lupinus albus var. Dorado Seedlings, for the Bioremediation of Mercury-Polluted Soils

Processes ◽

10.3390/pr9081293 ◽

2021 ◽

Vol 9 (8) ◽

pp. 1293

Author(s):

Daniel González ◽

Carlota Blanco ◽

Agustín Probanza ◽

Pedro A. Jiménez ◽

Marina Robas

Keyword(s):

Plant Growth ◽

Contaminated Soils ◽

Lupinus Albus ◽

Plant Growth Promoting Rhizobacteria ◽

Mining District ◽

Bacterial Strains ◽

Toxic Heavy Metals ◽

Plant Growth Promoting ◽

Growth Promoting ◽

High Concentrations

Soil contamination by mercury, which is one of the most toxic heavy metals due to its bioaccumulative capacity, poses a risk to the environment as well as health. The Almadén mining district in Ciudad Real, Spain is one of the most heavily-polluted sites in the world, making the soils unusable. Bioremediation, and more specifically phyto-rhizoremediation, based on the synergistic interaction established between plant and Plant Growth Promoting Rhizobacteria (PGPR), improves the plant's ability to grow, mobilize, accumulate, and extract contaminants from the soil. The objective of this study is to evaluate the plant growth-promoting ability of four PGPR strains (and mixtures), isolated from the bulk soil and rhizosphere of naturally grown plants in the Almadén mining district, when they are inoculated in emerged seeds of Lupinus albus, var. Dorado in the presence of high concentrations of mercury. After 20 days of incubation and subsequent harvesting of the seedlings, biometric measurements were carried out at the root and aerial levels. The results obtained show that the seeds treatment with PGPR strains improves plants biometry in the presence of mercury. Specifically, strain B2 (Pseudomonas baetica) and B1 (Pseudomonas moraviensis) were those that contributed the most to plant growth, both individually and as part of mixtures (CS5 and CS3). Thus, these are postulated to be good candidates for further in situ phyto-rhizoremediation tests of mercury-contaminated soils.

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Methylobacterium populiVP2: Plant Growth-Promoting Bacterium Isolated from a Highly Polluted Environment for Polycyclic Aromatic Hydrocarbon (PAH) Biodegradation

The Scientific World JOURNAL ◽

10.1155/2014/931793 ◽

2014 ◽

Vol 2014 ◽

pp. 1-11 ◽

Cited By ~ 28

Author(s):

Valeria Ventorino ◽

Filomena Sannino ◽

Alessandro Piccolo ◽

Valeria Cafaro ◽

Rita Carotenuto ◽

...

Keyword(s):

Plant Growth ◽

Plant Growth Promotion ◽

Contaminated Soils ◽

Environmental Remediation ◽

Growth Promotion ◽

Complex Mixture ◽

Simultaneous Occurrence ◽

Toxic Substances ◽

Plant Growth Promoting ◽

Growth Promoting

The use of microorganisms to accelerate the natural detoxification processes of toxic substances in the soil represents an alternative ecofriendly and low-cost method of environmental remediation compared to harmful incineration and chemical treatments. Fourteen strains able to grow on minimal selective medium with a complex mixture of different classes of xenobiotic compounds as the sole carbon source were isolated from the soil of the ex-industrial site ACNA (Aziende Chimiche Nazionali Associate) in Cengio (Savona, Italy). The best putative degrading isolate,Methylobacterium populiVP2, was identified using a polyphasic approach on the basis of its phenotypic, biochemical, and molecular characterisation. Moreover, this strain also showed multiple plant growth promotion activities: it was able to produce indole-3-acetic acid (IAA) and siderophores, solubilise phosphate, and produce a biofilm in the presence of phenanthrene and alleviate phenanthrene stress in tomato seeds. This is the first report on the simultaneous occurrence of the PAH-degrading ability byMethylobacterium populiand its multiple plant growth-promoting activities. Therefore, the selected indigenous strain, which is naturally present in highly contaminated soils, is good candidate for plant growth promotion and is capable of biodegrading xenobiotic organic compounds to remediate contaminated soil alone and/or soil associated with plants.

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