scholarly journals Hypaphorine from the Ectomycorrhizal Fungus Pisolithus tinctorius Counteracts Activities of Indole-3-Acetic Acid and Ethylene but Not Synthetic Auxins in Eucalypt Seedlings

2000 ◽  
Vol 13 (2) ◽  
pp. 151-158 ◽  
Author(s):  
Franck Anicet Ditengou ◽  
Frédéric Lapeyrie
Keyword(s):  
Acetic Acid ◽  
Root Colonization ◽  
Signal Transduction Pathway ◽  
Ectomycorrhizal Fungus ◽  
Pisolithus Tinctorius ◽  
Naphthaleneacetic Acid ◽  
Auxin Synthesis ◽  
Microbe Interactions ◽  
Dichlorophenoxy Acetic Acid ◽  
Indole 3 Acetic Acid

Very little is known about the molecules regulating the interaction between plants and ectomycorrhizal fungi during root colonization. The role of fungal auxin in ectomycorrhiza has repeatedly been suggested and questioned, suggesting that, if fungal auxin controls some steps of colonized root development, its activity might be tightly controlled in time and in space by plant and/or fungal regulatory mechanisms. We demonstrate that fungal hypaphorine, the betaine of tryptophan, counteracts the activity of indole-3-acetic acid (IAA) on eucalypt tap root elongation but does not affect the activity of the IAA analogs 2,4-D ((2,4-dichlorophenoxy)acetic acid) or NAA (1-naphthaleneacetic acid). These data suggest that IAA and hypaphorine interact during the very early steps of the IAA perception or signal transduction pathway. Furthermore, while seedling treatment with 1-amincocyclopro-pane-1-carboxylic acid (ACC), the precursor of ethylene, results in formation of a hypocotyl apical hook, hypaphorine application as well as root colonization by Pisolithus tinctorius, a hypaphorine-accumulating ectomycorrhizal fungus, stimulated hook opening. Hypaphorine counteraction with ACC is likely a consequence of hypaphorine interaction with IAA. In most plant-microbe interactions studied, the interactions result in increased auxin synthesis or auxin accumulation in plant tissues. The P. tinctorius / eucalypt interaction is intriguing because in this interaction the microbe down-regulates the auxin activity in the host plant. Hypaphorine might be the first specific IAA antagonist identified.

scholarly journals Foliar Thidiazuron Promotes the Growth of Axillary Buds in Strawberry

Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 594
Author(s):  
Yali Li ◽  
Jiangtao Hu ◽  
Jie Xiao ◽  
Ge Guo ◽  
Byoung Ryong Jeong
Keyword(s):  
Soluble Sugar ◽  
Signal Transduction Pathway ◽  
Axillary Buds ◽  
Axillary Bud ◽  
Naphthaleneacetic Acid ◽  
Auxin Synthesis ◽  
Bud Growth ◽  
Axillary Bud Growth ◽  
Soluble Sugar And Starch ◽  
Indole 3 Acetic Acid

Strawberry (Fragaria × ananassa Duch.) can be easily propagated with daughter plants or through crown division, which are developed from the axillary bud at the axils of leaves. This study was conducted to investigate the effects of different cytokinins, auxins, and their combinations on the axillary bud growth in strawberry. Four cytokinins (6-benzyladenine, kinetin, zeatin, and thidiazuron (TDZ)) and three auxins (indole-3-acetic acid, indole-3-butyric acid, and naphthaleneacetic acid) at a concentration of 50 mg·L−1 were sprayed on the leaves three times in 10-day intervals. The expression levels of cytokinin, auxin, and meristem-related genes in the crowns were also investigated. The results showed that TDZ was the most effective hormone for the axillary bud growth, and also promoted plant growth. However, chlorophyll, soluble sugar, and starch contents in the leaves were lower after TDZ. TDZ activated the cytokinin signal transduction pathway, while repressing the auxin synthesis genes. Several meristem-related transcription factors were upregulated, which might be essential for the growth of the axillary buds. These results suggested that TDZ can improve the cultivation of strawberry, while further research is needed to explain the effect on phytochemistry.

Plant Regeneration from Excised Cotyledons of Mature Strawberry Achenes

HortScience ◽  
1990 ◽  
Vol 25 (5) ◽  
pp. 569-571 ◽  
Author(s):  
A. Raymond Miller ◽  
Craig K. Chandler
Keyword(s):  
Acetic Acid ◽  
Plant Regeneration ◽  
Multiple Shoot ◽  
Naphthaleneacetic Acid ◽  
Developmental Studies ◽  
Shoot Buds ◽  
Cotyledon Explants ◽  
Multiple Shoot Buds ◽  
Rapid Regeneration ◽  
Dichlorophenoxy Acetic Acid

A protocol was developed for excising and culturing cotyledon explants from mature achenes of strawberry (Fragaria × ananassa Duch.). Cotyledon explants formed callus with multiple shoot buds on agar-solidified Murashige and Skoog media containing several combinations of hormones (1 μm 2,4-D; 10 μm 2,4-D; 1 μm BA + 1 μm 2,4-D; 1 μm BA + 10 μm 2,4-D; 5 μm BA; 5 μm BA + 1 μm 2,4-D; 5 μm BA + 10 μ m 2,4-D; 5 μ m BA + 5 μm NAA; 5 μ m BA + 15 μ m NAA). After three subcultures, only tissues maintained on the medium containing 5 μm BA + 5 μm NAA continued to form shoots. Tissues transferred to other media eventually died (1 μm 2,4-D; 1 μ m BA + 10 μ m 2,4-D; 5 μ m BA; 5 μ m BA + 1 μ m 2,4-D), became unorganized (1 μm BA + 1 μm 2,4-D; 5 μm BA + 10 μm 2,4-D; 5 μm BA + 15 μm NAA), or formed roots (10 μm 2,4-D). Whole plantlets were produced by transferring callus with buds to medium lacking hormones. The rapid regeneration of clonal plantlets from cotyledon explants may be useful for reducing variability in future developmental studies. Chemical names used: N-(phenylmethyl)-1H-purin-6-amine (BA); (2,4-dichlorophenoxy) acetic acid (2,4-D); and 1-naphthaleneacetic acid (NAA).

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.

Effect of auxin and phenobarbital on the ultrastructure and digitoxin content in Digitalis purpurea tissue culture

1996 ◽  
Vol 74 (3) ◽  
pp. 378-382 ◽  
Author(s):  
Mercedes Bonfill ◽  
Javier Palazón ◽  
Rosa M. Cusidó ◽  
M. Teresa Piñol ◽  
Carmen Morales
Keyword(s):  
Acetic Acid ◽  
Volume Fraction ◽  
Volume Ratio ◽  
Naphthaleneacetic Acid ◽  
Acetic Acid Medium ◽  
Digitalis Purpurea ◽  
Murashige Skoog ◽  
Mitochondrial Volume ◽  
Callus Tissues ◽  
Indole 3 Acetic Acid

Callus derived from Digitalis purpurea hypocotils were grown during a 6-week period on solid Murashige–Skoog medium supplemented with 1 mg/L 6-benzylaminopurine, 0.01 mg/L gibberellic acid and 0.1 mg/L indole-3-acetic acid or α-naphthaleneacetic acid, with or without phenobarbital (40 mg/L). The presence of phenobarbital in the culture medium caused a reduction of the vacuole/cytoplasm ratio. At the same time, the chloroplastic volume fraction decreased in callus tissue cells grown in media supplemented with phenobarbital, while the mitochondrial volume ratio increased. Digitoxin content was enhanced in callus tissues, especially in those grown on indole-3-acetic acid medium supplemented with phenobarbital. The relationship between ultrastructure of D. purpurea callus and digitoxin content is discussed. Keywords: Digitalis purpurea tissue cultures, digitoxin, phenobarbital, mitochondria, chloroplast.

The Route, Control and Compartmentation of Auxin Synthesis

1993 ◽  
Vol 20 (5) ◽  
pp. 527 ◽  
Author(s):  
HM Nonhebel ◽  
TP Cooney ◽  
R Simpson
Keyword(s):  
Amino Acids ◽  
Acetic Acid ◽  
Recent Work ◽  
Aspartate Aminotransferase ◽  
Acid Synthesis ◽  
Pea Seedlings ◽  
Auxin Synthesis ◽  
Aromatic Aminotransferase ◽  
Work Supports ◽  
Indole 3 Acetic Acid

The study of indole-3-acetic acid synthesis has undergone something of a revival recently in an attempt to understand the control of IAA levels. Results are, however, contradictory with three separate hypotheses emerging. Our own work supports older evidence for L-tryptophan as the IAA precursor and appears to simplify the metabolism of tryptophan to IAA. Work comparing incorporation of 2H from 2H2O into IAA, tryptophan, tryptamine and indole-3-pyruvate in tomato shoots showed that the indole-3-pyruvate became labelled at a rate compatible with it being the sole intermediate between tryptophan and indole-3-acetaldehyde. Results also showed that tryptamine was not involved in IAA synthesis although it was present. Indole-3-acetaldoxime was not detected in tomato shoots. An aromatic aminotransferase able to catalyse the synthesis of indole-3-pyruvate has been purified from mung beans. This enzyme was separated from aspartate aminotransferase and is fairly specific for aromatic L-amino acids. Other work, however, has implicated D-tryptophan as a more direct precursor than the L-enantiomer. A D-tryptophan aminotransferase has been isolated from dark grown pea seedlings. Finally, other recent work has indicated the existence of an alternative biosynthetic route to IAA which does not involve tryptophan. These results are reviewed in this paper and the apparent contradictions between them discussed.

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