Phytotoxicity of Indole-3-acetic Acid Produced by the Fungus,<i>Pythium aphanidermatum</i>

Shimada, Atsumi; Takeuchi, Sumiyo; Nakajima, Akira; Tanaka, Satoshi; Kawano, Tsuyoshi; Kimura, Yasuo

doi:10.1271/bbb.64.187

Cited by 24 publications

(19 citation statements)

References 4 publications

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“…The tryptamine pathway is common in the Pythium genus and has been found in P. oligandrum strains and in plant-pathogenic Pythium species. For instance, the pathogens P. dissotocum and P. ultimum produce indole-3-acetic acid and tryptophol from tryptophan (47,52). This study shows that under the same experimental conditions, P. oligandrum synthesized only tryptamine from a tryptophan precursor, with no other auxin metabolites detected.…”

Section: Discussionmentioning

confidence: 66%

Influence of Pythium oligandrum Biocontrol on Fungal and Oomycete Population Dynamics in the Rhizosphere

Vallance

Floch

Déniel

et al. 2009

Appl Environ Microbiol

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Fungal and oomycete populations and their dynamics were investigated following the introduction of the biocontrol agent Pythium oligandrum into the rhizosphere of tomato plants grown in soilless culture. Three strains of P. oligandrum were selected on the basis of their ability to form oospores (resting structures) and to produce tryptamine (an auxin-like compound) and oligandrin (a glycoprotein elicitor). Real-time PCR and plate counting demonstrated the persistence of large amounts of the antagonistic oomycete in the rhizosphere throughout the cropping season (April to September). Inter-simple-sequence-repeat analysis of the P. oligandrum strains collected from root samples at the end of the cropping season showed that among the three strains used for inoculation, the one producing the smallest amount of oospores was detected at 90%. Single-strand conformational polymorphism analysis revealed increases in the number of members and the complexity of the fungal community over time. There were no significant differences between the microbial ecosystems inoculated with P. oligandrum and those that were not treated, except for a reduction of Pythium dissotocum (ubiquitous tomato root minor pathogen) populations in inoculated systems during the last 3 months of culture. These findings raise interesting issues concerning the use of P. oligandrum strains producing elicitor and auxin molecules for plant protection and the development of biocontrol.

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Section: Discussionmentioning

confidence: 66%

Influence of Pythium oligandrum Biocontrol on Fungal and Oomycete Population Dynamics in the Rhizosphere

Vallance

Floch

Déniel

et al. 2009

Appl Environ Microbiol

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“…The genetic mechanism of auxin biosynthesis and regulation by Pseudomonas, Agrobacterium, Rhizobium, Bradyrhizobium, and Azospirillum are well studied (30). A pathogenic fungus of rice, Pythium aphanidermatum is known to produce and accumulate IAA in host plants, that is 200 times higher than that in normal plants, and causes serious leaf-bent symptom (31). Recent studies have confirmed that fungal IAA controls major anatomical features and gene expression in ectomycorrhiza such as that of pine (32,33), spruce (34) and Eucalyptus (35,36).…”

Section: Role Of Fungal Auxins and Related Compoundsmentioning

confidence: 99%

Fungal Auxin Antagonist Hypaphorine Competitively Inhibits Indole-3-acetic Acid-Dependent Superoxide Generation by Horseradish Peroxidase

Kawano

Hosoya

et al. 2001

Biochemical and Biophysical Research Communications

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“…Quantitative analysis of indole-3-acetic acid (IAA) in petunia corollas was carried out according to the modified method of Akiyama et al (1983), Shimada et al (2000) and Crozier et al (1980). The fresh corollas (0.3 g) were homogenized in 25 ml 80% acetone in water with a Polytron equipment (Kinematica) at the mediumspeed setting for 60 s, and the homogenate was centrifuged (4 ∞C, 2,000 ¥ g, 5 min).…”

Section: Iaa Content Of Corollasmentioning

confidence: 99%

Nitrogen Metabolism and Flower Symmetry of Petunia Corollas Treated with Glyphosate

Shimada

Kimura

2007

Zeitschrift Für Naturforschung C

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A change of flower shape was observed in petunia corollas treated with 0.5 mm glyphosate. Glyphosate changed the flower symmetry from the actinomorphic type to the zygomorphic type. Corollas treated with glyphosate showed an increased free amino acid content. Free amino acid profiles in petunia corollas revealed that glyphosate had no significant effect on aromatic amino acid levels but increased the level of proline. Soluble protein content in glyphosate-treated corollas did not cause any significant changes. The contents of soluble phenolics, lignin, and IAA in the corollas were not significantly affected by the glyphosate treatment. In contrast, glyphosate reduced the nitrate content and the RNA content of petunia corollas by 45% and 63% of the control, respectively. However, the DNA content in glyphosate-treated corollas was similar to that of the control.Low concentrations of glyphosate did not show any phytotoxic effects on the whole plants and any remarkable changes on aromatic amino acid metabolism and protein synthesis. However, glyphosate reduced the RNA content of petunia corollas and changed the flower symmetry from the actinomorphic type to the zygomorphic type. The results of nonprotein nitrogen metabolism in glyphosate-treated petunia corollas suggested that glyphosate application at low concentration may influence the regulation of flower symmetry through the change of RNA biosynthesis.

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Phytotoxicity of Indole-3-acetic Acid Produced by the Fungus,Pythium aphanidermatum

Cited by 24 publications

References 4 publications

Influence of Pythium oligandrum Biocontrol on Fungal and Oomycete Population Dynamics in the Rhizosphere

Influence of Pythium oligandrum Biocontrol on Fungal and Oomycete Population Dynamics in the Rhizosphere

Fungal Auxin Antagonist Hypaphorine Competitively Inhibits Indole-3-acetic Acid-Dependent Superoxide Generation by Horseradish Peroxidase

Nitrogen Metabolism and Flower Symmetry of Petunia Corollas Treated with Glyphosate

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