scholarly journals Transgenically Enhanced Expression of Indole-3-Acetic Acid Confers Hypervirulence to Plant Pathogens

2002 ◽  
Vol 92 (6) ◽  
pp. 590-596 ◽  
Author(s):  
Barry A. Cohen ◽  
Ziva Amsellem ◽  
Rudy Maor ◽  
Amir Sharon ◽  
Jonathan Gressel
Keyword(s):  
Acetic Acid ◽  
Plant Pathogens ◽  
Low Doses ◽  
Wild Type ◽  
Tomato Plants ◽  
Pathogen Virulence ◽  
Enhanced Expression ◽  
Auxin Herbicides ◽  
Dichlorophenoxy Acetic Acid ◽  
Indole 3 Acetic Acid

Fusarium oxysporum and F. arthrosporioides, pathogenic on Orobanche aegyptiaca, were transformed with two genes of the indole-3-acetamide (IAM) pathway leading to indole-3-acetic acid (IAA) to attempt to enhance virulence. Transgenic F. oxysporum lines containing both the tryptophan-2-monooxyngenase (iaaM) and indole-3-acetamide hydrolase (iaaH) genes produced significantly more IAA than the wild type. IAM accumulated in culture extracts of F. oxysporum containing iaaM alone. F. arthrosporioides containing only iaaM accumulated IAM and an unidentified indole. Some transformants of F. oxysporum expressing only the iaaM gene also produced more IAA than the wild type. Sub-threshold levels (that barely infect Orobanche) of transgenic F. oxysporum expressing both genes and of F. arthrosporioides expressing iaaM were more effective in suppressing the number and size of Orobanche shoots than the wild type on tomato plants grown in soil mixed with Orobanche seed. Stimulating an auxin imbalance enhanced pathogen virulence by affecting the host in a manner similar to low doses of auxin herbicides such as 2,4-dichlorophenoxy acetic acid.

Movement of Several Herbicides Through Excised Plant Tissue

Weed Science ◽  
1970 ◽  
Vol 18 (1) ◽  
pp. 64-68 ◽  
Author(s):  
T. D. Taylor ◽  
G. F. Warren
Keyword(s):  
Acetic Acid ◽  
Phaseolus Vulgaris ◽  
Plant Tissue ◽  
The Other ◽  
Tissue Orientation ◽  
Chemical Retention ◽  
Dichlorophenoxy Acetic Acid ◽  
Indole 3 Acetic Acid

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.

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 Improvement of Phosphate Solubilization and Medicago Plant Yield by an Indole-3-Acetic Acid-Overproducing Strain of Sinorhizobium meliloti

2010 ◽  
Vol 76 (14) ◽  
pp. 4626-4632 ◽  
Author(s):  
Carmen Bianco ◽  
Roberto Defez
Keyword(s):  
Acetic Acid ◽  
Plant Growth ◽  
Type Strain ◽  
Sinorhizobium Meliloti ◽  
Wild Type Strain ◽  
Dry Weight ◽  
Limiting Factors ◽  
Wild Type ◽  
System A ◽  
Indole 3 Acetic Acid

ABSTRACT Nitrogen (N) and phosphorus (P) are the most limiting factors for plant growth. Some microorganisms improve the uptake and availability of N and P, minimizing chemical fertilizer dependence. It has been published that the RD64 strain, a Sinorhizobium meliloti 1021 strain engineered to overproduce indole-3-acetic acid (IAA), showed improved nitrogen fixation ability compared to the wild-type 1021 strain. Here, we present data showing that RD64 is also highly effective in mobilizing P from insoluble sources, such as phosphate rock (PR). Under P-limiting conditions, the higher level of P-mobilizing activity of RD64 than of the 1021 wild-type strain is connected with the upregulation of genes coding for the high-affinity P transport system, the induction of acid phosphatase activity, and the increased secretion into the growth medium of malic, succinic, and fumaric acids. Medicago truncatula plants nodulated by RD64 (Mt-RD64), when grown under P-deficient conditions, released larger amounts of another P-solubilizing organic acid, 2-hydroxyglutaric acid, than plants nodulated by the wild-type strain (Mt-1021). It has already been shown that Mt-RD64 plants exhibited higher levels of dry-weight production than Mt-1021 plants. Here, we also report that P-starved Mt-RD64 plants show significant increases in both shoot and root fresh weights when compared to P-starved Mt-1021 plants. We discuss how, in a Rhizobium-legume model system, a balanced interplay of different factors linked to bacterial IAA overproduction rather than IAA production per se stimulates plant growth under stressful environmental conditions and, in particular, under P starvation.

scholarly journals Chlorinated Auxins—How Does Arabidopsis Thaliana Deal with Them?

2020 ◽  
Vol 21 (7) ◽  
pp. 2567 ◽  
Author(s):  
Antje Walter ◽  
Lorenzo Caputi ◽  
Sarah O’Connor ◽  
Karl-Heinz van Pée ◽  
Jutta Ludwig-Müller
Keyword(s):  
Arabidopsis Thaliana ◽  
Acetic Acid ◽  
Model Organism ◽  
Wild Type ◽  
In Planta ◽  
Bacteria And Fungi ◽  
Tryptophan Derivatives ◽  
Indole 3 Acetic Acid ◽  
Iaa Conjugates

Plant hormones have various functions in plants and play crucial roles in all developmental and differentiation stages. Auxins constitute one of the most important groups with the major representative indole-3-acetic acid (IAA). A halogenated derivate of IAA, 4-chloro-indole-3-acetic acid (4-Cl-IAA), has previously been identified in Pisum sativum and other legumes. While the enzymes responsible for the halogenation of compounds in bacteria and fungi are well studied, the metabolic pathways leading to the production of 4-Cl-IAA in plants, especially the halogenating reaction, are still unknown. Therefore, bacterial flavin-dependent tryptophan-halogenase genes were transformed into the model organism Arabidopsis thaliana. The type of chlorinated indole derivatives that could be expected was determined by incubating wild type A. thaliana with different Cl-tryptophan derivatives. We showed that, in addition to chlorinated IAA, chlorinated IAA conjugates were synthesized. Concomitantly, we found that an auxin conjugate synthetase (GH3.3 protein) from A. thaliana was able to convert chlorinated IAAs to amino acid conjugates in vitro. In addition, we showed that the production of halogenated tryptophan (Trp), indole-3-acetonitrile (IAN) and IAA is possible in transgenic A. thaliana in planta with the help of the bacterial halogenating enzymes. Furthermore, it was investigated if there is an effect (i) of exogenously applied Cl-IAA and Cl-Trp and (ii) of endogenously chlorinated substances on the growth phenotype of the plants.

The Effect of Metabolic Inhibitors on Herbicide Movement in Plants

Weed Science ◽  
1970 ◽  
Vol 18 (1) ◽  
pp. 68-74 ◽  
Author(s):  
T. D. Taylor ◽  
G. F. Warren
Keyword(s):  
Acetic Acid ◽  
Phaseolus Vulgaris ◽  
Cucumis Sativus ◽  
Metabolic Inhibitors ◽  
Stems And Leaves ◽  
Whole Plants ◽  
Dichlorophenoxy Acetic Acid ◽  
Indole 3 Acetic Acid

Pretreatment of bean (Phaseolus vulgarisL.) petiole sections with one of several metabolic inhibitors greatly stimulated the movement of 3-amino-2,5-dichlorobenzoic acid (amiben) and (2,4-dichlorophenoxy)acetic acid (2,4-D). However, the movement of 3-amino-s-triazole (amitrole), 3-(3,4-dichlorophenyl)-1-methylurea (linuron), and isopropylm-chlorocarbanilate (chlorpropham) was stimulated only slightly or not at all. The basipetal movement of indole-3-acetic acid (IAA) was inhibited by concentrations of 2-sec-butyl-4,6-dinitrophenol (dinoseb) which stimulated respiration (5 × 10−7M to 5 × 10−8M). Acropetal movement was stimulated by dinoseb concentrations greater than 10−5M. Translocation of root-applied amiben and 2,4-D to the stems and leaves of whole plants of bean, squash (Curcurbita pepoL.), and cucumber (Cucumis sativusL.) was stimulated by dinoseb root applications only at concentrations which were highly injurious to the plants. Amiben, 2,4-D, and their metabolites were extracted from dinosebtreated and untreated tissues. The stem exudate from cucumber plants fed amiben and 2,4-D via the roots contained primarily the parent compounds, which indicates that the parent compounds are the primary components translocated through the xylem.

scholarly journals The rolB-Like Part of the Agrobacterium rhizogenes orf8 Gene Inhibits Sucrose Export in Tobacco

2002 ◽  
Vol 15 (9) ◽  
pp. 956-962 ◽  
Author(s):  
Marie Umber ◽  
Lars Voll ◽  
Andreas Weber ◽  
Pierre Michler ◽  
Léon Otten
Keyword(s):  
Acetic Acid ◽  
Agrobacterium Rhizogenes ◽  
Mode Of Action ◽  
Sucrose Transporter ◽  
Naphthalene Acetic Acid ◽  
Wild Type ◽  
Sucrose Transport ◽  
Tobacco Plants ◽  
Indole 3 Acetic Acid ◽  
Lines Of Evidence

Many Agrobacterium T-DNA genes belong to the highly diverse rolB family. The mode of action of most of these genes is still unknown. rolB-like sequences also are present at the 5′ ends of the T-DNA-located iaaM genes and the iaaM homolog orf8, whereas iaaM genes from Pseudomonas and Erwinia spp. lack such sequences. iaaMgenes encode tryptophan monooxygenases; these enzymes convert tryptophan into indole-3-acetamide, a precursor of indole-3-acetic acid. Tobacco plants expressing the rolB-like part of the A4 orf8 gene (2×35S-A4-Norf8 plants) accumulate glucose, fructose, sucrose, and starch and resemble sucrose transporter (NtSUT1) antisense plants. Different lines of evidence indicate that 2×35S-A4-Norf8 plants export less sucrose from source leaves. Glucose, fructose, sucrose, and starch accumulate in source leaves during sink-source transition, whereas sink tissues like petioles and midveins contain lower levels than normal. Petiole exudation experiments demonstrate a significant decrease in export of label after 14C-sucrose infiltration and after 14CO2 labeling. Grafting of stunted homozygous 2×35S-A4-Norf8 plants onto wild-type rootstocks restores growth, indicating that unloading is not affected. Growth of 2×35S-A4-Norf8 seedlings is inhibited on naphthalene acetic acid-containing media, suggesting a link between sucrose transport and auxin sensitivity.

scholarly journals Global Effect of Indole-3-Acetic Acid Biosynthesis on Multiple Virulence Factors of Erwinia chrysanthemi 3937

2006 ◽  
Vol 73 (4) ◽  
pp. 1079-1088 ◽  
Author(s):  
Shihui Yang ◽  
Qiu Zhang ◽  
Jianhua Guo ◽  
Amy O. Charkowski ◽  
Bernard R. Glick ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Posttranscriptional Regulation ◽  
Fluorescent Protein ◽  
Pectate Lyase ◽  
Erwinia Chrysanthemi ◽  
Wild Type ◽  
T3ss Effector ◽  
Green Fluorescent ◽  
Indole 3 Acetic Acid ◽  
Promoter Activity Assay

ABSTRACT Production of the plant hormone indole-3-acetic acid (IAA) is widespread among plant-associated microorganisms. The non-gall-forming phytopathogen Erwinia chrysanthemi 3937 (strain Ech3937) possesses iaaM (ASAP16562) and iaaH (ASAP16563) gene homologues. In this work, the null knockout iaaM mutant strain Ech138 was constructed. The IAA production by Ech138 was reduced in M9 minimal medium supplemented with l-tryptophan. Compared with wild-type Ech3937, Ech138 exhibited reduced ability to produce local maceration, but its multiplication in Saintpaulia ionantha was unaffected. The pectate lyase production of Ech138 was diminished. Compared with wild-type Ech3937, the expression levels of an oligogalacturonate lyase gene, ogl, and three endopectate lyase genes, pelD, pelI, and pelL, were reduced in Ech138 as determined by a green fluorescent protein-based fluorescence-activated cell sorting promoter activity assay. In addition, the transcription of type III secretion system (T3SS) genes, dspE (a putative T3SS effector) and hrpN (T3SS harpin), was found to be diminished in the iaaM mutant Ech138. Compared with Ech3937, reduced expression of hrpL (a T3SS alternative sigma factor) and gacA but increased expression of rsmA in Ech138 was also observed, suggesting that the regulation of T3SS and pectate lyase genes by IAA biosynthesis might be partially due to the posttranscriptional regulation of the Gac-Rsm regulatory pathway.

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