Antagonistic Activity of Indigenous Rhizobacteria through Biosynthesis of Indole-3-Acetic Acid (IAA), Hydrogen Cyanide (HCN), and Siderophores

This study aimed to isolate indigenous Antagonistic Bacteria (AB) against common soil-borne phytopathogens, including Rhizoctonia solani, Phythium sp., Fusarium oxysporum. Biosynthesis of Indole-3-Acetic Acid (IAA), generation of Hydrogen Cyanide (HCN), and siderophores production were assessed for their involvement in the antagonistic activities. Rhizospheric soil of bean roots, sunflowers, wheat, rice, and humic and semi flooded soils were used to isolate twenty-one bacterial strains for phytopathogenic antagonism. It was found that nine isolates have potential antagonistic activity against three common soilborne pathogens. Antifungal productivity for IAA, HCN, and siderophores was screened on the isolates while nine ABs were identified. To choose statistically significant isolate for the formulation, the principal component analysis was performed with five variables (IAA production, siderophores production index, antagonistic activities against three phytopathogens). Among the nine isolates, the isolate Pseudomonas alicaligenes shew a positive correlation with all variables. In particular, the strain demonstrated to be an antagonistic strain against the fungal pathogens and a strong producer of siderophores, HCN and IAA, We prepared the biocontrol agents with rice flour, glutinous rice flour, Monosodium Glutamate and Chitosan that were found to maintain the up to three months for convenience of field applications.

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Effects of Co-Inoculation of Indole-3-Acetic Acid-Producing and -Degrading Bacterial Endophytes on Plant Growth

Horticulturae ◽

10.3390/horticulturae5010017 ◽

2019 ◽

Vol 5 (1) ◽

pp. 17 ◽

Cited By ~ 4

Author(s):

Sabitri Adhikari Dhungana ◽

Kazuhito Itoh

Keyword(s):

Acetic Acid ◽

Plant Growth ◽

Liquid Medium ◽

Bacterial Production ◽

Root Weight ◽

Bacterial Endophytes ◽

Bacterial Strains ◽

Plant Parts ◽

Degrading Bacteria ◽

Indole 3 Acetic Acid

Bacterial production of indole-3-acetic acid (IAA) and its effects on plant growth have been frequently studied but there have been few studies on the ecology of IAA-degrading bacteria. In this study, among eight endophytic bacterial strains previously isolated from the same sweet potato sample including two IAA producers, Klebsiella sp. Sal 1 and Enterobacter sp. Sal 3, all of the strains showed IAA-degrading ability to some extent. Herbaspirillum sp. Sal 6 had the highest activity for IAA and tryptophan. When the IAA producers and the degrader were co-cultured in tryptophan-amended N+MR liquid medium, the concentrations of IAA decreased. Inoculation with Klebsiella sp. Sal 1, the highest IAA producer among the test strains, increased fresh root weight of tomato and radish, but the effect decreased by co-inoculation with IAA-degrading Herbaspirillum sp. Sal 6. Since both strains colonized plant parts at high populations, it was likely that the IAA degrader decreased IAA levels in the plants by degrading IAA and/or its precursor tryptophan. When IAA-producing biofertilizers are used, interactions with IAA degraders in plants should be considered.

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Isolation and Biochemical Characterization of Indole-3-Acetic Acid (IAA) Produced in Pseudomonas Sp. Isolated from Rhizospheric Soil

International Journal for Research in Applied Sciences and Biotechnology ◽

10.31033/ijrasb.8.4.1 ◽

2021 ◽

Vol 8 (4) ◽

Author(s):

Utkalendu Suvendusekhar Samantaray ◽

Swapnarani Sethi

Keyword(s):

Acetic Acid ◽

Indole Acetic Acid ◽

Biochemical Characterization ◽

Stem Elongation ◽

Lateral Roots ◽

Rhizospheric Soil ◽

Bacterial Strains ◽

Physiological Processes ◽

Crucial Component ◽

Indole 3 Acetic Acid

A phytohormone is a molecule that controls the development of plants. Auxin and cytokines, which may be acquired as synthetic compounds or produced by microorganisms, which promote plant growth, are employed to enhance crop yield. Indole-3-Acetic Acid (IAA) is a key phytohormone that controls a number of physiological processes in plants. Indole-3-acetic acid (IAA), the most prevalent endogenous auxin, is involved in stem elongation and root formation. Auxin levels are usually higher in the rhizosphere. The possibility of rhizosphere bacteria to encourage direct plant development has been recognised as a crucial component of auxin (IAA) production. They promote the growth of lateral roots, which increases the surface area available for nutrition absorption and enhances nutrient and water absorption from the soil. The objective of this research is to isolate, characterise, and identify bacteria that produce indole acetic acid in rhizospheric soil. Bacterial colonies were isolated using the serial dillution technique on nutrient agar medium from rhizospheric soil samples of a rice crop. Five rhizospheric bacterial isolates (RIPB-1 to RIPB-30) were identified as effective Indole acetic acid makers after qualitative screening. The quantity of Indole acetic acid produced by five bacterial strains was tested for up to 120 hours. The amount of Indole acetic acid they could generate ranged from 1 to 11.2 g/ml. The bacterial strain RIPB-20 (11.2 g/ml) generated the highest Indole acetic acid after 72 hours of incubation, followed by RIPB-14. Based on morphological, physiological, and biochemical features, the bacterial isolate RIPB-20 was tentatively identified as Bacillus sp. Finally, the finding shows that the bacteria, which have capacity to produce Indole acetic acid, are good biofertilizer inoculants for growth of plant.

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The differential effects of indole-3-acetic acid and its metabolites on the development of Puccinia graminis f. sp. tritici in vitro

Canadian Journal of Botany ◽

10.1139/b79-217 ◽

1979 ◽

Vol 57 (17) ◽

pp. 1765-1768

Author(s):

Hans J. Grambow ◽

Marie Th. Tücks

Keyword(s):

Acetic Acid ◽

Mycelial Growth ◽

Rust Fungus ◽

Axenic Culture ◽

Antagonistic Activity ◽

Puccinia Graminis ◽

A Minor ◽

Indole 3 Acetic Acid

3,3′-Bisindolylmethane (BIM), and to a minor degree, 3-methyleneoxindole (MeOx) stimulated mycelial growth in axenic culture of the rust fungus Puccinia graminis f. sp. tritici, race 32, and transition from germ tube to mycelial growth. The effect of BIM was clearly antagonized by indole-3-acetic acid (IAA) and by indole-3-aldehyde (IAld). On the contrary, indole-3-carboxylic acid (ICarb) had a very low antagonistic activity. These results led us to the hypothesis that the balance of the steady-state concentrations of IAA and the various IAA metabolites may be critically involved in the control of the development of the rust fungus in vivo.

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Targeted engineering of Azospirillum brasilense SM with indole acetamide pathway for indoleacetic acid over-expression

Canadian Journal of Microbiology ◽

10.1139/w06-071 ◽

2006 ◽

Vol 52 (11) ◽

pp. 1078-1084 ◽

Cited By ~ 23

Author(s):

Mandira Malhotra ◽

Sheela Srivastava

Keyword(s):

Acetic Acid ◽

Metabolic Engineering ◽

Azospirillum Brasilense ◽

Constitutive Expression ◽

Biomass Productivity ◽

Dry Weight ◽

Molecular Evidence ◽

Bacterial Strains ◽

Indole 3 Acetic Acid ◽

Iaa Biosynthesis

Rhizospheric bacterial strains are known to produce indole-3-acetic acid (IAA) through different pathways, and such IAA may be beneficial to plants at low concentrations. IAA biosynthesis by a natural isolate of Azospirillum brasilense SM was studied and observed to be tryptophan-inducible and -dependent in nature. While our work demonstrated the operation of the indole pyruvic acid pathway, the biochemical and molecular evidence for the genes of the indole acetamide (IAM) pathway were lacking in A. brasilense SM. This led us to use the IAM pathway genes as targets for metabolic engineering, with the aim of providing an additional pathway of IAA biosynthesis and improving IAA levels in A. brasilense SM. The introduction of the heterologous IAM pathway, consisting of the iaaM and iaaH genes, not only increased the IAA levels by threefold but also allowed constitutive expression of the same genes along with efficient utilization of IAM as a substrate. Such an engineered strain showed a superior effect on the lateral branching of sorghum roots as well as the dry weight of the plants when compared with the wild-type strain. Such an improved bioinoculant could be demonstrated to enhance root proliferation and biomass productivity of treated plants compared with the parental strain.Key words: indole-3-acetic acid, tryptophan, indole-3-acetamide, iaaM-iaaH, metabolic engineering.

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