Studies on the role of indole-3-acetic acid and cytokinins in the formation of knots on olive and oleander plants by Pseudomonas syringae pv. savastanoi

1985 ◽  
Vol 26 (3) ◽  
pp. 309-320 ◽  
Author(s):  
G. Surico ◽  
N.S. Iacobellis ◽  
A. Sisto
Keyword(s):  
Acetic Acid ◽  
Pseudomonas Syringae ◽  
Indole 3 Acetic Acid

scholarly journals Indole-3-Acetaldehyde Dehydrogenase-dependent Auxin Synthesis Contributes to Virulence ofPseudomonas syringaeStrain DC3000

2017 ◽  
Author(s):  
Sheri A. McClerklin ◽  
Soon Goo Lee ◽  
Ron Nwumeh ◽  
Joseph M. Jez ◽  
Barbara N. Kunkel
Keyword(s):  
Acetic Acid ◽  
Pseudomonas Syringae ◽  
Virulence Factors ◽  
Plant Hormone ◽  
Disease Development ◽  
Hormone Signaling ◽  
Host Defenses ◽  
Acetaldehyde Dehydrogenase ◽  
Indole 3 Acetic Acid

AbstractThe bacterial pathogenPseudomonas syringaemodulates plant hormone signaling to promote infection and disease development.P. syringaeuses several strategies to manipulate auxin physiology inArabidopsis thalianato promote pathogenesis, including synthesis of indole-3-acetic acid (IAA), the predominant form of auxin in plants, and production of virulence factors that alter auxin responses in the host; however, the role of pathogen-derived auxin inP. syringaepathogenesis is not well understood. Here we demonstrate thatP. syringaestrain DC3000 produces IAA via a previously uncharacterized pathway and identify a novel indole-3-acetaldehyde dehydrogenase, AldA, that functions in IAA biosynthesis by catalyzing the NAD-dependent formation of IAA from indole-3-acetaldehyde (IAAld). Biochemical analysis and solving of the 1.9 Å resolution x-ray crystal structure reveal key features of AldA for IAA synthesis, including the molecular basis of substrate specificity. Disruption ofaldAand a close homolog,aldB, lead to reduced IAA production in culture and reduced virulence onA. thaliana.We use these mutants to explore the mechanism by which pathogen-derived auxin contributes to virulence and show that IAA produced by DC3000 suppresses salicylic acid-mediated defenses inA. thaliana.Thus, auxin is a DC3000 virulence factor that promotes pathogenicity by suppressing host defenses.Author SummaryPathogens have evolved multiple strategies for suppressing host defenses and modulating host physiology to promote colonization and disease development. For example, the plant pathogenPseudomonas syringaeuses several strategies to the manipulate hormone signaling of its hosts, including production of virulence factors that alter hormone responses in and synthesis of plant hormones or hormone mimics. Synthesis of indole-3-acetic acid (IAA), a common form of the plant hormone auxin, by many plant pathogens has been implicated in virulence. However, the role of pathogen-derived IAA during pathogenesis by leaf spotting pathogens such asP. syringaestrain DC3000 is not well understood. Here, we demonstrate thatP. syringaestrain DC3000 uses a previously uncharacterized biochemical pathway to synthesize IAA, catalyzed by a novel aldehyde dehydrogenase, AldA, and carry out biochemical and structural studies of the AldA protein to investigate AldA activity and substrate specificity. We also generate analdAmutant disrupted in IAA synthesis to show that IAA is a DC3000 virulence factor that promotes pathogenesis by suppressing host defense responses.

Role of Indole-3-Acetic Acid in NAFLD Amelioration After Sleeve Gastrectomy

2021 ◽  
Author(s):  
Yu Wang ◽  
Geng Wang ◽  
Jie Bai ◽  
Ning Zhao ◽  
Qingbo Wang ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Sleeve Gastrectomy ◽  
Indole 3 Acetic Acid

scholarly journals Role of Growth Regulators on In Vitro Callus Induction and Direct Regeneration in Physalis minima Linn

2015 ◽  
Vol 44 ◽  
pp. 38-44 ◽  
Author(s):  
H. Sandhya ◽  
Rao Srinath
Keyword(s):  
Acetic Acid ◽  
Growth Regulators ◽  
Callus Induction ◽  
Basal Medium ◽  
Direct Regeneration ◽  
Naphthalene Acetic Acid ◽  
Stem Explants ◽  
Dichlorophenoxy Acetic Acid ◽  
Indole 3 Acetic Acid

Suitable protocol for induction of callus and regeneration was developed from different explants viz., node, stem and leaves in Physalis minima. MS basal medium supplemented with various concentrations (1.0-4.0mg/l) of auxins like 2,4-Dichlorophenoxy acetic acid (2,4-D), α-naphthalene acetic acid (NAA) and Indole-3-acetic acid (IAA) and cytokinins (0.5-1.5mg/l) like BAP or Kn were used. All the three explants responded for induction of callus, however stem explants were found superior, followed by node and leaf. Callus induction was observed in all the auxins and combination of growth regulators used with varied mass (2010±1.10) and highest percentage of callus induction was observed from stem at 2.0mg/l 2,4-D (90%) followed by NAA (70%) and IAA (50%). Organogenesis was induced when nodal explants were transferred on MS medium supplemented with 2,4-D and Kn at various concentrations, maximum being on 2.0mg/l 2,4-D + 1.0mg/l Kn (90%). Regenerated shoots were elongated on 0.5mg/l GA3. The shoots were subsequently rooted on MS + 1.0mg/l IBA (95%) medium. Rooted shoots were hardened and acclimatized, later they were transferred to polycups containing soil, cocopeat and sand in the ratio 1:2:1.Keywords:Physalis minima, Node, Stem, Leaf, callus and growth regulators.

scholarly journals Effects of Variations in Hormonal Treatments Upon In vitro Regeneration Potential in Embryo Explants of Arenga pinnata

2021 ◽  
Vol 17 (5) ◽  
pp. 495-503
Author(s):  
Shamsiah Abdullah ◽  
Siti Nurain Roslan
Keyword(s):  
Acetic Acid ◽  
In Vitro Regeneration ◽  
Hormonal Treatment ◽  
Height Increment ◽  
Regeneration Potential ◽  
In Vitro Method ◽  
Indole 3 Acetic Acid ◽  
Hormonal Treatments

One of the challenges related to propagation of Arenga pinnata is its lengthy period of seed dormancy. In this study, in vitro regeneration was carried out to determine the effect of hormonal treatment on the embryo explant of Arenga pinnata. Embryos were surface sterilized and cultured into different media supplemented with various hormones concentrations and combinations. Each treatment contained of Kinetin (KN) hormone (1.0, 2.0, and 3.0 mg/l) and in combination with indole-3-acetic acid (IAA) of 0.1, 0.2, 0.3 mg/l. The height of plumule and length of radical was observed and recorded. Treatment 8 (3 mg/ml KN + 0.1 mg/ml IAA) showed 59.09% in plumule height increment while treatment 4 (1 mg/ml KN + 0.3 mg/ml IAA) showed the highest radical increments with 93.62%. The knowledge gained in this study consequently helps us to better understand the role of KN and IAA in the in vitro regeneration protocol. Since in vitro method able to produce higher number of in vitro seedlings at one time, it is important to establish the in vitro regeneration protocol for this plant.

scholarly journals The Role of Indole-3-Acetic Acid and Acid Invertase in the Development of Melon (Cucumis melo L. cv. Prince) Fruit

1997 ◽  
Vol 65 (4) ◽  
pp. 723-729 ◽  
Author(s):  
Tae-Ho Lee ◽  
Tohru Kato ◽  
Yoshinori Kanayama ◽  
Hajime Ohno ◽  
Kiyotoshi Takeno ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Cucumis Melo ◽  
Acid Invertase ◽  
Cucumis Melo L ◽  
Indole 3 Acetic Acid

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

1996 ◽  
Vol 42 (6) ◽  
pp. 586-592 ◽  
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.

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

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.

The Role of Horseradish Peroxidase in Indole-3-acetic Acid Oxidation*

Biochemistry ◽  
1965 ◽  
Vol 4 (12) ◽  
pp. 2754-2763 ◽  
Author(s):  
L. Raymond Fox ◽  
William K. Purves ◽  
Henry I. Nakada
Keyword(s):  
Acetic Acid ◽  
Horseradish Peroxidase ◽  
Acid Oxidation ◽  
Indole 3 Acetic Acid

scholarly journals iac Gene Expression in the Indole-3-Acetic Acid-Degrading Soil Bacterium Enterobacter soli LF7

2018 ◽  
Vol 84 (19) ◽  
Author(s):  
Isaac V. Greenhut ◽  
Beryl L. Slezak ◽  
Johan H. J. Leveau
Keyword(s):  
Gene Expression ◽  
Acetic Acid ◽  
Promoter Region ◽  
Deletion Mutant ◽  
Plant Hormone ◽  
Major Facilitator Superfamily ◽  
Soil Bacterium ◽  
Content Type ◽  
Indole 3 Acetic Acid

ABSTRACT We show for soil bacterium Enterobacter soli LF7 that the possession of an indole-3-acetic acid catabolic (iac) gene cluster is causatively linked to the ability to utilize the plant hormone indole-3-acetic acid (IAA) as a carbon and energy source. Genome-wide transcriptional profiling by mRNA sequencing revealed that these iac genes, chromosomally arranged as iacHABICDEFG and coding for the transformation of IAA to catechol, were the most highly induced (>29-fold) among the relatively few (<1%) differentially expressed genes in response to IAA. Also highly induced and immediately downstream of the iac cluster were genes for a major facilitator superfamily protein (mfs) and enzymes of the β-ketoadipate pathway (pcaIJD-catBCA), which channels catechol into central metabolism. This entire iacHABICDEFG-mfs-pcaIJD-catBCA gene set was constitutively expressed in an iacR deletion mutant, confirming the role of iacR, annotated as coding for a MarR-type regulator and located upstream of iacH, as a repressor of iac gene expression. In E. soli LF7 carrying the DNA region upstream of iacH fused to a promoterless gfp gene, green fluorescence accumulated in response to IAA at concentrations as low as 1.6 μM. The iacH promoter region also responded to chlorinated IAA, but not other aromatics tested, indicating a narrow substrate specificity. In an iacR deletion mutant, gfp expression from the iacH promoter region was constitutive, consistent with the predicted role of iacR as a repressor. A deletion analysis revealed putative −35/−10 promoter sequences upstream of iacH, as well as a possible binding site for the IacR repressor. IMPORTANCE Bacterial iac genes code for the enzymatic conversion of the plant hormone indole-3-acetic acid (IAA) to catechol. Here, we demonstrate that the iac genes of soil bacterium Enterobacter soli LF7 enable growth on IAA by coarrangement and coexpression with a set of pca and cat genes that code for complete conversion of catechol to central metabolites. This work contributes in a number of novel and significant ways to our understanding of iac gene biology in bacteria from (non-)plant environments. More specifically, we show that LF7's response to IAA involves derepression of the MarR-type transcriptional regulator IacR, which is quite fast (less than 25 min upon IAA exposure), highly specific (only in response to IAA and chlorinated IAA, and with few genes other than iac, cat, and pca induced), relatively sensitive (low micromolar range), and seemingly tailored to exploit IAA as a source of carbon and energy.

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