Screening of Azotobacter isolates for PGP properties and antifungal activity

?mong 50 bacterial isolates obtained from maize rhizospher?, 13 isolates belonged to the genus Azotobacter. Isolates were biochemically characterized and estimated for pH and halo tolerance ability and antibiotic resistance. According to characterization, the six representative isolates were selected and further screened in vitro for plant growth promoting properties: production of indole-3-acetic acid (IAA), siderophores, hydrogen cyanide (HCN), exopolysaccharides, phosphate solubilization and antifungal activity (vs. Helminthosporium sp., Macrophomina sp., Fusarium sp.). Beside HCN production, PGP properties were detected for all isolates except Azt7. All isolates produced IAA in the medium without L-tryptophan and the amount of produced IAA increased with concentration of precursor in medium. The highest amount of IAA was produced by isolates Azt4 (37.69 and 45.86 ?g ml-1) and Azt5 (29.44 and 50.38 ?g ml-1) in the medium with addition of L-tryptophan (2.5 and 5 mM). The isolates showed the highest antifungal activity against Helminthosporium sp. and the smallest antagonistic effect on Macrophomina sp. Radial Growth Inhibition (RGI) obtained by the confrontation of isolates with tested phytopathogenic fungi, ranged from 10 to 48%.

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In vitro antagonistic potential, plant growth-promoting activity and indole-3-acetic acid producing trait of bacterial isolates from spent mushroom substrate of Agaricus bisporus

Journal of Agricultural and Marine Sciences [JAMS] ◽

10.24200/jams.vol25iss2pp22-29 ◽

2020 ◽

Vol 25 (2) ◽

pp. 22

Author(s):

Rethinasamy Velazhahan ◽

Shima Nasser Hamed Al-Mamari ◽

Abdullah Mohammed Al-Sadi ◽

Issa Hashil Al-Mahmooli ◽

S. P. Sathish Babu

Keyword(s):

Plant Growth ◽

Agaricus Bisporus ◽

Growth Promotion ◽

Inhibition Zone ◽

Bacterial Isolates ◽

Plant Growth Promoting ◽

Antagonistic Potential ◽

Growth Promoting ◽

Indole 3 Acetic Acid

Spent mushroom substrate (SMS) is widely used as fertilizer and to control plant diseases. The microorganisms surviving in SMS play a crucial role in plant growth promotion and biocontrol properties of SMS. In this study, an effort was made to isolate and characterize the bacterial species present in the SMS of Agaricus bisporus and to study their antagonistic potential, plant growth-promoting ability and indole-3-acetic acid (IAA) producing trait. Six different bacterial isolates exhibiting morphological variabilities were obtained from the SMS by serial dilution technique. On the basis of 16S rRNA gene sequences, these isolates were identified as Staphylococcus epidermidis (Sh1 and Sh3), S. aureus (Sh2), Bacillus albus (Sh4), Delftia lacustris (Sh6) and Comamonas aquatica (Sh7). These bacterial strains were assayed for their antagonism against Pythium aphanidermatum, a phytopathogenic oomycete. The results of in vitro dual culture assay revealed that all the 6 bacterial isolates showed low levels of suppression of P. aphanidermatum and recorded less than 5 mm inhibition zone. Among the bacterial isolates, S. epidermidis Sh3 recorded the maximum inhibition zone of 4.2 mm. Plant growth promotion test using roll paper towel method revealed that C. aquatica Sh7, B. albus Sh4, D. lacustris Sh6 and S. epidermidis Sh3 caused a significant increase in seedling vigour of cucumber compared to control. The seeds treated with the bacterial isolate C. aquatica Sh7 showed the maximum seedling vigor. Assessment of in vitro production of IAA by the bacterial isolates revealed that the bacterial isolates highly varied (ranging from 0.28 to 9.25 mg L-1) in their potential for production of IAA. The maximum amount of IAA was produced by C. aquatica Sh7 (9.25 mg L-1), while the minimum was produced by S. epidermidis Sh1 (0.28 mg L-1).

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Screening for Potential Plant Growth-Promoting Rhizobacteria (PGPR) Associated with Five Musa spp. Cultivars in SOCCSKSARGEN, Philippines

Journal of Engineering Environment and Agriculture Research ◽

10.34002/jeear.v1i0.17 ◽

2018 ◽

Vol 1 ◽

pp. 5

Author(s):

Giuseppe Haydn Lacorte ◽

Remedios S. Flamiano ◽

Malona V. Alinsug ◽

Paolo M. Tagaloguin

Keyword(s):

Microbial Population ◽

Phosphate Solubilization ◽

Plant Growth Promoting Rhizobacteria ◽

Bacterial Isolates ◽

Iaa Production ◽

Phosphate Solubilizers ◽

Rhizospheric Bacteria ◽

Nitrogen Fixers ◽

Plant Growth Promoting ◽

Growth Promoting

Rhizospheric bacteria (PGPR) associated with 5 banana cultivars planted in SOCCSKSARGEN were studied. Microbial population in newly established and old plantation was compared. Bacteria were purified and their beneficial characteristics were determined. This study was able to collect one hundred twenty (120) bacterial isolates, 20 (17%) of which were nitrogen-fixers, nineteen (19/20) were phosphate solubilizers and seventeen (17/20) were IAA producers. From this study, five bacterial isolates coded PE05, RS10, PE11, PE13, and PE18 were found positive for nitrogen fixation, phosphate solubilization and IAA production which may be further evaluated for their potential application in the formulation of biofertilizers for banana cultivation. Read full article here.

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Mechanism of phosphate solubilization and antifungal activity of Streptomyces spp. isolated from wheat roots and rhizosphere and their application in improving plant growth

Microbiology ◽

10.1099/mic.0.074146-0 ◽

2014 ◽

Vol 160 (4) ◽

pp. 778-788 ◽

Cited By ~ 107

Author(s):

Rahul Jog ◽

Maharshi Pandya ◽

G. Nareshkumar ◽

Shalini Rajkumar

Keyword(s):

Gene Expression ◽

Antifungal Activity ◽

Plant Growth ◽

Potential Field ◽

Phosphate Solubilization ◽

Isocitrate Lyase ◽

Malate Synthase ◽

Plant Growth Promoting Activities ◽

Plant Growth Promoting ◽

Growth Promoting

The application of plant-growth-promoting rhizobacteria (PGPR) at field scale has been hindered by an inadequate understanding of the mechanisms that enhance plant growth, rhizosphere incompetence and the inability of bacterial strains to thrive in different soil types and environmental conditions. Actinobacteria with their sporulation, nutrient cycling, root colonization, bio-control and other plant-growth-promoting activities could be potential field bio-inoculants. We report the isolation of five rhizospheric and two root endophytic actinobacteria from Triticum aestivum (wheat) plants. The cultures exhibited plant-growth-promoting activities, namely phosphate solubilization (1916 mg l−1), phytase (0.68 U ml−1), chitinase (6.2 U ml−1), indole-3-acetic acid (136.5 mg l−1) and siderophore (47.4 mg l−1) production, as well as utilizing all the rhizospheric sugars under test. Malate (50–55 mmol l−1) was estimated in the culture supernatant of the highest phosphate solublizer, Streptomyces mhcr0816. The mechanism of malate overproduction was studied by gene expression and assays of key glyoxalate cycle enzymes – isocitrate dehydrogenase (IDH), isocitrate lyase (ICL) and malate synthase (MS). The significant increase in gene expression (ICL fourfold, MS sixfold) and enzyme activity (ICL fourfold, MS tenfold) of ICL and MS during stationary phase resulted in malate production as indicated by lowered pH (2.9) and HPLC analysis (retention time 13.1 min). Similarly, the secondary metabolites for chitinase-independent biocontrol activity of Streptomyces mhcr0817, as identified by GC-MS and 1H-NMR spectra, were isoforms of pyrrole derivatives. The inoculation of actinobacterial isolate mhce0811 in T. aestivum (wheat) significantly improved plant growth, biomass (33 %) and mineral (Fe, Mn, P) content in non-axenic conditions. Thus the actinobacterial isolates reported here were efficient PGPR possessing significant antifungal activity and may have potential field applications.

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Isolation and characterization of plant growth-promoting endophytic bacteria of wild legumes growing on sandy soils of Binh Thuan province, Vietnam

World Journal of Advanced Research and Reviews ◽

10.30574/wjarr.2021.10.3.0274 ◽

2021 ◽

Vol 10 (3) ◽

pp. 246-254

Author(s):

Dang Thi Ngoc Thanh ◽

Pham Thi Thu Ly ◽

Pham Thi Nga ◽

Pham Van Ngot

Keyword(s):

Nitrogen Fixation ◽

Plant Growth ◽

Endophytic Bacteria ◽

Phosphate Solubilization ◽

Sandy Soils ◽

Legume Species ◽

Bacterial Isolates ◽

Isolation And Characterization ◽

Plant Growth Promoting ◽

Growth Promoting

The roots of two legume species (Tephrosia purpurea and Tephrosia villosa) that grew wild on dry sandy soils of Binh Thuan province were sources for isolating plant growth-promoting endophytic bacteria. Semi-solid LGI medium was used for the isolation of nitrogen-fixing bacteria from root extracts. All bacterial isolates isolates were evaluated for their ability to solubilize calcium orthophosphate on solid NBRIP medium and their ability to produce IAA in Burk's liquid medium supplemented with 100 mg/L tryptophan. The possibilities of nitrogen fixation, phosphate solubilization and IAA synthesis were all quantitative examined by colorimetric method. Twenty-two bacterial isolates of T. purpurea and 18 isolates of T. villosa were capable of nitrogen fixation in the range of 1.94 to 2.81 mg/L NH4+, whereas only 18 isolates of T. purpurea and 16 isolates of T. villosa showed phosphate solubilization in the range of 12.30 – 48.90 mg/L P2O5, and IAA production in the range of 0.38 – 12.72 mg/L. Sixteen outstanding bacterial isolates of the two legume species were identified by MALDI-TOF technique. The results showed that 13 isolates had high similarity with five bacterial genera including Klebsiella, Cronobacter, Enterobacter, Burkholderia, and Bacillus with score values in the range of 2.070 – 2.411.

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Plant growth-promoting activity in bean plants of endophytic bacteria isolated from Echeveria laui

Acta Brasiliensis ◽

10.22571/2526-4338496 ◽

2021 ◽

Vol 5 (2) ◽

pp. 65

Author(s):

Anderson Emmer ◽

João Arthur Dos Santos Oliveira ◽

Andressa Domingos Polli ◽

Julio Cesar Polonio ◽

Leonardo Hamamura Alves ◽

...

Keyword(s):

Plant Growth ◽

Endophytic Bacteria ◽

Arid Environment ◽

Bacterial Isolates ◽

Phaseolus Vulgaris L ◽

Bean Plants ◽

Plant Growth Promoting ◽

Plant Growth Promoting Activity ◽

Growth Promoting

Echeveria laui (Crassulaceae) is commonly commercialized due to its drought-tolerance capacity and to its rosette-shaped aesthetics. Since endophytes associated with plants from a dry or arid environment have scarcely been analyzed as yet, current research comprises the isolation of leaf endophytic bacteria from E. laui (one five-year-old and one two-year-old plants) investigating plant growth-promoting endophytic bacteria which may solubilize phosphate, fix nitrogen, produce exopolysaccharides/IAA and antagonize phytopathogens. Isolation by the maceration methodology provided a colonization rate of 1.98 x109 CFU g-1 for the two-year-old plant and 1.14 x 1010 CFU g-1 for the five-year-old one. All 40 isolates evaluated showed in vitro plant growth-promoting agent’s abilities, with emphasis on EG04, ELG18, and ELP06. The capacity of the three best bacterial isolates were evaluated under greenhouse conditions in common and black bean (Phaseolus vulgaris L.) plants. Based on the sequencing of the 16S rRNA region and phylogenetic analysis, the three endophytes were identified as Pantoea sp. (ELG04 and ELG18) and Erwinia sp. (ELP06). Under greenhouse conditions, statistically significant differences were found among the plants treated with the three endophytes when compared to control plants for fresh and dry shoot, root biomass and length.

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Evaluation of diverse range microbes for their plant growth promoting abilities and their pesticide compatibility

Environment Conservation Journal ◽

10.36953/ecj.2021.22306 ◽

2021 ◽

pp. 47-58

Author(s):

Tulja Sanam ◽

S. Triveni ◽

J. Satyanaryana ◽

Sridhar Goud Nerella ◽

K. Damodara Chari ◽

...

Keyword(s):

Plant Growth ◽

Plant Growth Promoting Rhizobacteria ◽

Atomic Absorption Spectrophotometry ◽

In Vitro Assays ◽

Bacterial Isolates ◽

Diverse Range ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Bacillus Isolate

Plant growth-promoting rhizobacteria (PGPR) contribute to an increase in crop yield through an environmentally friendly method, therefore eight rhizospheric bacteria, two of each genera Bacillus, Pseudomonas, Azotobacter and Azospirillum were examined for their efficacy to solubilize mineral nutrients using atomic absorption spectrophotometry and a flame photometer. Their potency to produce phytohormones, synthesis biocontrol components and their compatibility with pesticides using in vitro assays was studied. All of the chosen bacterial isolates proved positive for the above-mentioned Plant Growth Promoting traits. Among the eight bacterial isolates Pseudomonas isolate P69 showed the highest phosphorous solubilization efficiency of 190.91 % and another isolate P48 produced a maximum of 27.63µg mL-1 of gibberellic acid, Bacillus isolate B120 could solubilize maximum amount of ZnO and ZnCO3 accounting for 21.3ppm and 25.9ppm, respectively, not merely in terms of solubilization when compared to the other isolates, B120 produced the highest levels of HCN (77.33 ppm TCC) and siderophores (48.87psu). On day 9 after inoculation, Azotobacter isolate AZB17 performed effectively in potassium solubilization of 6.25g mL-1 with a pH drop to 3.83. The Azospirillum isolate ASP25 outperformed all other isolates in terms of IAA production (22.64g mL-1) and Bacillus isolate B365 was found to be more compatible with eight different pesticides used in the field at varying concentrations. All of these factors point to the possibility of using these bacterial isolates B120, P48, P69, AZB17, and ASP25 as biofertilizers in sustainable agriculture.

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A Survey of Methylobacterium Species and Strains Reveals Widespread Production and Varying Profiles of Cytokinin Phytohormones

10.21203/rs.3.rs-1034994/v1 ◽

2021 ◽

Author(s):

Daniel Palberg ◽

Anna Kisiała ◽

Gabriel Lemes Jorge ◽

R. J. Neil Emery

Keyword(s):

High Performance ◽

Active Form ◽

Plant Growth Promoting Bacteria ◽

Liquid Chromatography Tandem Mass ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Selection For ◽

Indole 3 Acetic Acid

Abstract BackgroundSymbiotic Methylobacterium strains comprise a significant part of plant microbiomes. Their presence enhances plant productivity and stress resistance, prompting classification of these strains as plant growth-promoting bacteria (PGPB). Methylobacteria can synthesize unusually high levels of plant hormones, called cytokinins (CKs), including the most active form, trans-Zeatin (tZ). ResultsThis study provides a comprehensive inventory of 46 representatives of Methylobacterium genus with respect to phytohormone production in vitro, including 16 CK forms, abscisic acid (ABA) and indole-3-acetic acid (IAA). High performance-liquid chromatography - tandem mass spectrometry (HPLC-MS/MS) analyses revealed varying abilities of Methylobacterium strains to secrete phytohormones that ranged from 5.09 to 191.47 pmol mL-1 for total CKs, and 0.46 to 82.16 pmol mL-1 for tZ. Results indicate that reduced methanol availability, the sole carbon source for bacteria in the medium, stimulates CK secretion by Methylobacterium. Additionally, select strains were able to transform L-tryptophan into IAA while no ABA production was detected.ConclusionsTo better understand features of CKs in plants, this study uncovers CK profiles of Methylobacterium that are instrumental in microbe selection for effective biofertilizer formulations.

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Effect of Pseudomonas aeruginosa ZGKD2 on the Growth of Amorpha fruticosa L in Coal Gangue

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.807-809.2023 ◽

2013 ◽

Vol 807-809 ◽

pp. 2023-2026

Author(s):

Yu Xiu Zhang ◽

Pei Li Shi ◽

Qian Zhang

Keyword(s):

Pseudomonas Aeruginosa ◽

Acetic Acid ◽

Plant Growth ◽

Root Length ◽

Phosphate Solubilization ◽

Fresh Weight ◽

Amorpha Fruticosa ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Indole 3 Acetic Acid

The cadmium-resistant Pseudomonas aeruginosa strain ZGKD2 was isolated from gangue pile of coal area. Production of siderophores, indole-3-acetic acid (IAA) and the solubilization of phosphate were observed in the strain. Two types of siderophores were identified by UV spectrophotometer. The highest production of IAA and phosphate solubilization were 2.0 ug/mL and 7.2 ug/mL. The root length, plant height and fresh weight of Amorpha fruticosa L in the substrates of Coal gannue and losses were promoted after inoculation with ZGKD2. These data indicated that Pseudomonas aeruginosa strain ZGKD2 was a plant growth-promoting bacterial (PGPB).

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Evaluation of Antifusarium and Auxin Production of Trichoderma virens InaCC F1030 Isolated from Rhizosphere of Banana

Journal of Microbial Systematics and Biotechnology ◽

10.37604/jmsb.v2i1.39 ◽

2020 ◽

Vol 2 (1) ◽

pp. 31-39

Author(s):

Toga Pangihotan Napitupulu

Keyword(s):

Culture Collection ◽

Trichoderma Virens ◽

Plant Host ◽

Trichoderma Species ◽

Auxin Production ◽

Volatile Organic ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Indole 3 Acetic Acid

Banana rhizosphere harbors a unique diversity of microbes including fungi that play critical roles in the growth of the plant host as well as might be important for biologically controlling the fungal soil-borne pathogens particularly Fusarium oxysporum f.sp. cubense (Foc), the causing agent of devastating Panama wilt. Among other fungi, we have succeeded to isolate a Trichoderma species from rhizosphere of healthy banana. Molecular identification revealed the isolate as Trichoderma virens InaCC F1030 (being collection of Indonesian Culture Collection or InaCC). Therefore, the aim of this study was to investigate the biological control of our isolate against Foc as well as plant growth promoting ability through its ability to produce auxin (indole-3-acetic acid/IAA). Two approaches were employed to evaluate the antagonism of our isolate against Foc, through direct confrontation test and volatile organic compounds (VOCs) producing. We found that our isolate was considered as antagonistic to the Foc, but not highly antagonistic according to direct confrontation assay. It was also revealed that our isolate produces the VOCs that inhibited around 50% of the mycelial growth of the test pathogen after six to seven days of exposure. Our isolate was able to produce the IAA in axenic submerged fermentation condition particularly in the presence of the precursor L-tryptophan. IAA production ability as well as the mycelial biomass of fungus were increased approximately 17% and 120% respectively as the effect of supplementation of 0.1% of L-tryptophan. These in vitro bioassays lead us to conclude that somehow our isolate T. virens InaCC F1030 has potency to be utilized as biocontrol and biofertilizer agent.

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Identification of antagonistic Streptomyces strains isolated from Algerian Saharan soils and their plant growth promoting properties

Biodiversitas Journal of Biological Diversity ◽

10.13057/biodiv/d211212 ◽

2020 ◽

Vol 21 (12) ◽

Author(s):

Lamia AOUAR ◽

INAS BOUKELLOUL ◽

ABDERRAHMANE BENADJILA

Keyword(s):

Plant Growth ◽

Phytopathogenic Fungi ◽

Growth Promoter ◽

Bioactive Substances ◽

Plant Growth Promoting ◽

Streptomyces Scabiei ◽

Growth Promoting ◽

Antagonistic Streptomyces

Abstract. Aouar L, Boukelloul I, Benadjila A. 2020. Identification of antagonistic Streptomyces strains isolated from Algerian Saharan soils and their plant growth promoting properties. Biodiversitas 21: 5672-5683. To produce new bioactive substances of agricultural interest, extreme ecosystems can be a source of unexplored microorganisms. Accordingly, in this study, twenty-two actinobacteria strains were obtained from rhizospheric arid soils of palm groves collected from Biskra and El Oued in the Algerian Sahara. All isolates were examined for the in vitro antifungal potential towards phytopathogenic fungi: Aspergillus flavus, Verticillium dahlia, Rhizoctonia solani, Botrytis cinerea and Fusarium oxysporum as well as for their antibacterial property toward phytopathogenic bacteria: Streptomyces scabiei, Pectobacterium carotovorum and Agrobacterium tumefaciens. The three isolates (13%) that inhibited at least five pathogens were then selected, identified and assessed for their attributes to produce indole-3-acetic acid (IAA) and siderophores, to solubilize phosphate, and to antagonize Streptomyces scabiei in vivo. According to phylogenetic analysis performed with 16S rDNA sequence, chemotaxonomy and phenotypic characteristics, the strain SO1, which inhibited all tested pathogens, was assigned to Streptomyces flaveus. While, strains SO2 and SB1 were affiliated to Streptomyces enissocaesilis and Streptomyces albidoflavus, respectively. All strains produced IAA but only SO1 and SB1 were able to elaborate siderophores catecholate-type. Two strains SO1 and SO2 exhibited a capacity to solubilize phosphate and SO1 was able to suppress the pathogenic effect of Streptomyces scabiei on radish seedlings. The findings indicate that SO1 strain may reveal the potential for use as a biocontrol agent and plant growth promoter.

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