A mutation in the indole-3-acetic acid biosynthesis pathway of Pseudomonas syringae pv. syringae affects growth in Phaseolus vulgaris and syringomycin production.

Uptake and movement of various herbicides and auxins by bean (Phaseolus vulgarisL.) petiole sections were studied. Isopropylm-chlorocarbanilate (chlorpropham) was the most mobile of the compunds studied, followed in order of decreasing mobility by: indole-3-acetic acid (IAA), 3-amino-s-triazole (amitrole), (2,4-dichlorophenoxy)acetic acid (2,4-D), 3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea (linuron), and 3-amino-2,5-dichlorobenzoic acid (amiben). Amiben immobilization may have been due to glucoside formation in the tissues. IAA was rapidly transported through basipetally but not acropetally oriented tissue. Tissue orientation had little effect on the movement of the other compounds. Mobility of the compounds studied, in general, appears to be a function of the amount of uncomplexed parent chemical. Retention is likely the result of conjugation with products in the cells or of physical binding in the cells.

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Characterization of the indole-3-acetic acid (IAA) biosynthetic pathway in an epiphytic strain of Erwinia herbicola and IAA production in vitro

Canadian Journal of Microbiology ◽

10.1139/m96-079 ◽

1996 ◽

Vol 42 (6) ◽

pp. 586-592 ◽

Cited By ~ 35

Author(s):

M. Brandi ◽

E. M. Clark ◽

S. E. Lindow

Keyword(s):

Acetic Acid ◽

Pseudomonas Syringae ◽

Pyruvic Acid ◽

Enzyme Assays ◽

Erwinia Herbicola ◽

Iaa Production ◽

Acid Pathway ◽

Culture Supernatants ◽

Indole 3 Acetic Acid

An epiphytic strain of Erwinia herbicola (strain 299R) synthesized indole-3-acetic acid (IAA) from indole-3-pyruvic acid and indole-3-acetaldehyde, but not from indole-3-acetamide and other intermediates of various IAA biosynthetic pathways in enzyme assays. TLC, HPLC, and GC–MS analyses revealed the presence of indole-3-pyruvic acid, indole-3-ethanol, and IAA in culture supernatants of strain 299R. Indole-3-acetaldehyde was detected in enzyme assays. Furthermore, strain 299R genomic DNA shared no homology with the iaaM and iaaH genes from Pseudomonas syringae pv. savastanoi, even in Southern hybridizations performed under low-stringency conditions. These observations strongly suggest that unlike gall-forming bacteria which can synthesize IAA by indole-3-acetamide, the indole-3-pyruvic acid pathway is the primary route for IAA biosynthesis in this plant-associated strain. IAA synthesis in tryptophan-supplemented cultures of strain 299R was over 10-fold higher under nitrogen-limiting conditions, indicating a possible role for IAA production by bacterial epiphytes in the acquisition of nutrients during growth in their natural habitat.Key words: indole-3-acetic acid, Erwinia, tryptophan, indole-3-pyruvic acid, nitrogen.

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Identification of IAA-regulated genes in Pseudomonas syringae pv. tomato strain DC3000

Journal of Bacteriology ◽

10.1128/jb.00380-21 ◽

2021 ◽

Author(s):

Arnaud-Thierry Djami-Tchatchou ◽

Zipeng Alex Li ◽

Paul Stodghill ◽

Melanie J. Filiatrault ◽

Barbara N. Kunkel

Keyword(s):

Gene Expression ◽

Arabidopsis Thaliana ◽

Acetic Acid ◽

Stress Response ◽

Pseudomonas Syringae ◽

Plant Pathogen ◽

Type Iii Secretion ◽

Plant Hormone ◽

Indole 3 Acetic Acid ◽

Exogenous Iaa

The auxin indole-3-acetic acid (IAA) is a plant hormone that not only regulates plant growth and development but also plays important roles in plant-microbe interactions. We previously reported that IAA alters expression of several virulence-related genes in the plant pathogen Pseudomonas syringae pv. tomato strain DC3000 ( Pto DC3000). To learn more about the impact of IAA on regulation of Pto DC3000 gene expression we performed a global transcriptomic analysis of bacteria grown in culture, in the presence or absence of exogenous IAA. We observed that IAA repressed expression of genes involved in the Type III secretion (T3S) system and motility and promoted expression of several known and putative transcriptional regulators. Several of these regulators are orthologs of factors known to regulate stress responses and accordingly expression of several stress response-related genes was also upregulated by IAA. Similar trends in expression for several genes were also observed by RT-qPCR. Using an Arabidopsis thaliana auxin receptor mutant that accumulates elevated auxin, we found that many of the P. syringae genes regulated by IAA in vitro were also regulated by auxin in planta . Collectively the data indicate that IAA modulates many aspects of Pto DC3000 biology, presumably to promote both virulence and survival under stressful conditions, including those encountered in or on plant leaves. IMPORTANCE Indole-3-acetic acid (IAA), a form of the plant hormone auxin, is used by many plant-associated bacteria as a cue to sense the plant environment. Previously, we showed that IAA can promote disease in interactions between the plant pathogen Pseudomonas syringae strain Pto DC000 and one of its hosts, Arabidopsis thaliana . However, the mechanisms by which IAA impacts the biology of Pto DC3000 and promotes disease are not well understood. Here we demonstrate that IAA is a signal molecule that regulates gene expression in Pto DC3000. The presence of exogenous IAA affects expression of over 700 genes in the bacteria, including genes involved in Type III secretion and genes involved in stress response. This work offers insight into the roles of auxin promoting pathogenesis.

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Influence of phenyl tryptophyl ether on adventitious root development in bean cuttings

Canadian Journal of Botany ◽

10.1139/b83-166 ◽

1983 ◽

Vol 61 (5) ◽

pp. 1548-1549 ◽

Cited By ~ 1

Author(s):

Bruce E. Haissig

Keyword(s):

Acetic Acid ◽

Phaseolus Vulgaris ◽

Root Development ◽

Adventitious Root ◽

Adventitious Root Development ◽

Indole 3 Acetic Acid

Rooting trials with bean (Phaseolus vulgaris cv. Top Crop L.) tested the effects of phenyl tryptophyl ether (PTRE) in comparison with tryptophol (TR, indole-3-ethanol), indole-3-acetic acid (IAA), and no treatment. PTRE was synthesized from tryptophol and phenol. Results indicated that IAA treatment enhanced primordium development significantly more than any other treatment that was tested. Effects of TR and PTRE treatment on primordium development were about equal. Results suggested that PTRE is not an auxin or is only a weak auxin in comparison with IAA.

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