Role of Aminotransferase and Indole-3-Pyruvic Acid in the Synthesis of Indole-3-Acetic Acid in Pseudomonas Savastanoi

Kuo, Tsong‐Teh; Kosuge, Tsune

doi:10.2323/jgam.16.3_191

Cited by 19 publications

(9 citation statements)

References 3 publications

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“…This provides more support for the hypothesis (36) that plant growth-promoting bacteria, such as Azospirillum spp. (10) and E. cloacae (24), produce IAA via the indolepyruvic acid pathway, in contrast to plant pathogens, which seem to preferentially synthesize IAA via the indoleacetamide pathway (25,48). Indeed, rendering the ipdc gene inactive by insertional mutagenesis and thereby eliminating IAA production by this pathway significantly reduces the ability of P. putida GR12-2 to promote primary root growth in canola seedlings.…”

Section: Discussionmentioning

confidence: 99%

Role of Pseudomonas putida Indoleacetic Acid in Development of the Host Plant Root System

Patten

Glick

2002

Appl Environ Microbiol

1,598

835

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Many plant-associated bacteria synthesize the phytohormone indoleacetic acid (IAA). While IAA produced by phytopathogenic bacteria, mainly by the indoleacetamide pathway, has been implicated in the induction of plant tumors, it is not clear whether IAA synthesized by beneficial bacteria, usually via the indolepyruvic acid pathway, is involved in plant growth promotion. To determine whether bacterial IAA enhances root development in host plants, the ipdc gene that encodes indolepyruvate decarboxylase, a key enzyme in the indolepyruvic acid pathway, was isolated from the plant growth-promoting bacterium Pseudomonas putida GR12-2 and an IAA-deficient mutant constructed by insertional mutagenesis. The canola seedling primary roots from seeds treated with wild-type P. putida GR12-2 were on average 35 to 50% longer than the roots from seeds treated with the IAA-deficient mutant and the roots from uninoculated seeds. In addition, exposing mung bean cuttings to high levels of IAA by soaking them in a suspension of the wild-type strain stimulated the formation of many, very small, adventitious roots. Formation of fewer roots was stimulated by treatment with the IAA-deficient mutant. These results suggest that bacterial IAA plays a major role in the development of the host plant root system.

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Section: Discussionmentioning

confidence: 99%

Role of Pseudomonas putida Indoleacetic Acid in Development of the Host Plant Root System

Patten

Glick

2002

Appl Environ Microbiol

1,598

835

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“…Production of IAM, however, is often related to production of IAA since the gene controlling the synthesis of IAM (iaaM) is genetically linked to that encoding the conversion of IAM to IAA (iaaH) (2,12). On the contrary, it is likely that IPyA could be synthesized by various bacteria as the result of nonspecific transamination of tryptophan (5,10,15). Even bacteria producing low amounts of IPyA could therefore be misidentified as auxin producers.…”

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confidence: 99%

A critical examination of the specificity of the salkowski reagent for indolic compounds produced by phytopathogenic bacteria

Glickmann¹,

Dessaux²

1995

Appl Environ Microbiol

908

367

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We examined the sensitivity and the specificity of three versions of the Salkowski colorimetric technique. Two of these allowed the detection of indoleacetic acid (IAA) over a low range of concentrations (0.5 to 20 g/ml), while the third permitted the detection of IAA over a range of higher concentrations (5 to 200 g/ml). Overall, the three formulations reacted not only with auxin (IAA) but also with indolepyruvic acid and indoleacetamide. Therefore, these techniques appear to be specific for IAA, indolepyruvic acid, and indoleacetamide rather than for IAA alone.

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“…In Pseudomonas syringae subsp. savastanoi, the olive and oleander knot pathogen, the biosynthesis of IAA via indolepyruvic acid is of minor significance compared to the formation of IAA via indoleacetamide (Kuo & Kosuge, 1970). …”

Section: Introductionmentioning

confidence: 99%

Indole-3-acetic acid (IAA) synthesis in the biocontrol strain CHA0 of Pseudomonas fluorescens: role of tryptophan side chain oxidase

Oberhänsli¹,

Défago²,

Haas

1991

Journal of General Microbiology

133

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Pseuhmonusfiorescens strain CHAO is an effective biocontrol agent against soil-borne fungal plant pathogens. In this study, indole-3-acetic acid (IAA) biosynthesis in strain CHAO was investigated. Two key enzyme activities were found to be involved: tryptophan side chain oxidase (TSO) and tryptophan transaminase. TSO was induced in the stationary growth phase. By fractionation of a cell extract of strain CHAO on DEAE-Sepharose, two distinct peaks of constitutive tryptophan transaminase activity were detected. A pathway leading from tryptophan to IAA via indole-3-acetamide, which occurs in Pseuhmonas syringtze subsp. savustanoi, was not present in strain CHAO. IAA synthesis accounted for 6 1.5% of exogenous tryptophan consumed by resting cells of strain CHAO, indicating that the bulk of tryptophan was catabolized via yet another pathway involving anthranilic acid as an intermediate. Strain CHA750, a mutant lacking TSO activity, was obtained after Tn5 mutagenesis of strain CHAO. In liquid cultures (pH 6.8) supplemented with 10 mM-L-tryptophan, growing cells of strains CHAO and CHA750 synthesized the same amount of IAA, presumably using the tryptophan transaminase pathway. In contrast, resting cells of strain CHA750 produced five times less IAA in a buffer (pH6-0) containing 1 mM-L-tryptophan than did resting cells of the wild-type, illustrating the major contribution of TSO to IAA synthesis under these conditions. In artificial soils at pH -7 or pH -6, both strains had similar abilities to suppress take-all disease of wheat or black root.rot of tobacco. This suggests that TSO-dependent IAA synthesis is not essential for disease suppression.

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Role of Aminotransferase and Indole-3-Pyruvic Acid in the Synthesis of Indole-3-Acetic Acid in Pseudomonas Savastanoi

Cited by 19 publications

References 3 publications

Role of Pseudomonas putida Indoleacetic Acid in Development of the Host Plant Root System

Role of Pseudomonas putida Indoleacetic Acid in Development of the Host Plant Root System

A critical examination of the specificity of the salkowski reagent for indolic compounds produced by phytopathogenic bacteria

Indole-3-acetic acid (IAA) synthesis in the biocontrol strain CHA0 of Pseudomonas fluorescens: role of tryptophan side chain oxidase

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