scholarly journals Dynamic regulation of auxin oxidase and conjugating enzymes AtDAO1 and GH3 modulates auxin homeostasis

2016 ◽  
Vol 113 (39) ◽  
pp. 11022-11027 ◽  
Author(s):  
Nathan Mellor ◽  
Leah R. Band ◽  
Aleš Pěnčík ◽  
Ondřej Novák ◽  
Afaf Rashed ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Plant Growth ◽  
Growth And Development ◽  
Extended Model ◽  
Plant Growth And Development ◽  
Dynamic Regulation ◽  
Auxin Homeostasis ◽  
High Auxin ◽  
Root Tissues ◽  
Indole 3 Acetic Acid

The hormone auxin is a key regulator of plant growth and development, and great progress has been made understanding auxin transport and signaling. Here, we show that auxin metabolism and homeostasis are also regulated in a complex manner. The principal auxin degradation pathways in Arabidopsis include oxidation by Arabidopsis thaliana gene DIOXYGENASE FOR AUXIN OXIDATION 1/2 (AtDAO1/2) and conjugation by Gretchen Hagen3s (GH3s). Metabolic profiling of dao1-1 root tissues revealed a 50% decrease in the oxidation product 2-oxoindole-3-acetic acid (oxIAA) and increases in the conjugated forms indole-3-acetic acid aspartic acid (IAA-Asp) and indole-3-acetic acid glutamic acid (IAA-Glu) of 438- and 240-fold, respectively, whereas auxin remains close to the WT. By fitting parameter values to a mathematical model of these metabolic pathways, we show that, in addition to reduced oxidation, both auxin biosynthesis and conjugation are increased in dao1-1. Transcripts of AtDAO1 and GH3 genes increase in response to auxin over different timescales and concentration ranges. Including this regulation of AtDAO1 and GH3 in an extended model reveals that auxin oxidation is more important for auxin homoeostasis at lower hormone concentrations, whereas auxin conjugation is most significant at high auxin levels. Finally, embedding our homeostasis model in a multicellular simulation to assess the spatial effect of the dao1-1 mutant shows that auxin increases in outer root tissues in agreement with the dao1-1 mutant root hair phenotype. We conclude that auxin homeostasis is dependent on AtDAO1, acting in concert with GH3, to maintain auxin at optimal levels for plant growth and development.

scholarly journals Redefining the roles of UDP-glycosyltransferases in auxin metabolism and homeostasis during plant development

2021 ◽  
Author(s):  
Eduardo Mateo-Bonmatí ◽  
Rubén Casanova-Sáez ◽  
Jan Šimura ◽  
Karin Ljung
Keyword(s):  
Acetic Acid ◽  
Plant Growth ◽  
Plant Development ◽  
Plant Growth Regulator ◽  
Growth And Development ◽  
Plant Tissues ◽  
Plant Growth And Development ◽  
Concentration Gradients ◽  
Indole 3 Acetic Acid ◽  
Reversible Nature

ABSTRACTThe levels of the important plant growth regulator indole-3-acetic acid (IAA) are tightly controlled within plant tissues to spatiotemporally orchestrate concentration gradients that drive plant growth and development. Metabolic inactivation of bioactive IAA is known to participate in the modulation of IAA maxima and minima. IAA can be irreversibly inactivated by oxidation and conjugation to Aspartate and Glutamate. Usually overlooked because its reversible nature, the most abundant inactive IAA form is the IAA-glucose (IAA-glc) conjugate. Glycosylation of IAA is reported to be carried out by the UDP-glycosyltransferase 84B1 (UGT84B1), while UGT74D1 has been implicated in the glycosylation of the irreversibly formed IAA catabolite oxIAA. Here we demonstrate that both UGT84B1 and UGT74D1 modulate IAA levels throughout plant development by dual IAA and oxIAA glycosylation. Moreover, we identify a novel UGT subfamily whose members modulate IAA homeostasis during skotomorphogenesis by redundantly mediating the glycosylation of oxIAA.

scholarly journals STRAIN ENTEROBACTER SP. UOM-3 IS ABLE TO SYNCHRONOUS DESTRUCTION OF HALOGEN-CONTAINING HERBICIDES AND SYNTHESIS OF INDOL-3-ACETIC ACID

ÈKOBIOTEH ◽  
2020 ◽  
Vol 3 (4) ◽  
pp. 716-721
Author(s):  
S.N. Starikov ◽  
◽  
S.P. Chetverikov ◽  
Keyword(s):  
Acetic Acid ◽  
Plant Growth ◽  
Growth And Development ◽  
Maximum Concentration ◽  
Culture Medium ◽  
Plant Growth And Development ◽  
Biological Product ◽  
Stimulate Plant Growth ◽  
Indole 3 Acetic Acid

We studied the Enterobacter sp. UOM-3 oil destructor strain that was isolated and identified earlier. During the study, it was shown that these bacteria are able to synthesize indole-3-acetic acid (IAA) when growing in culture medium with the halogen-containing herbicides Octapon and Florax: the destruction of 2,4-D on the 4th day of cultivation reached 79% and 68%, respectively, the maximum concentration of IAA during the experiment was 485 ng / ml and 270 ng / ml. The strain can be applied as part of a biological product to remediate the environment and to stimulate plant growth and development.

scholarly journals GH3 Auxin-Amido Synthetases Alter the Ratio of Indole-3-Acetic Acid and Phenylacetic Acid in Arabidopsis

2019 ◽  
Vol 61 (3) ◽  
pp. 596-605 ◽  
Author(s):  
Yuki Aoi ◽  
Keita Tanaka ◽  
Sam David Cook ◽  
Ken-Ichiro Hayashi ◽  
Hiroyuki Kasahara
Keyword(s):  
Acetic Acid ◽  
Plant Growth ◽  
Growth And Development ◽  
Phenylacetic Acid ◽  
Wild Type ◽  
Plant Growth And Development ◽  
Polar Movement ◽  
Wide Range ◽  
Metabolite Quantification ◽  
Indole 3 Acetic Acid

Abstract Auxin is the first discovered plant hormone and is essential for many aspects of plant growth and development. Indole-3-acetic acid (IAA) is the main auxin and plays pivotal roles in intercellular communication through polar auxin transport. Phenylacetic acid (PAA) is another natural auxin that does not show polar movement. Although a wide range of species have been shown to produce PAA, its biosynthesis, inactivation and physiological significance in plants are largely unknown. In this study, we demonstrate that overexpression of the CYP79A2 gene, which is involved in benzylglucosinolate synthesis, remarkably increased the levels of PAA and enhanced lateral root formation in Arabidopsis. This coincided with a significant reduction in the levels of IAA. The results from auxin metabolite quantification suggest that the PAA-dependent induction of GRETCHEN HAGEN 3 (GH3) genes, which encode auxin-amido synthetases, promote the inactivation of IAA. Similarly, an increase in IAA synthesis, via the indole-3-acetaldoxime pathway, significantly reduced the levels of PAA. The same adjustment of IAA and PAA levels was also observed by applying each auxin to wild-type plants. These results show that GH3 auxin-amido synthetases can alter the ratio of IAA and PAA in plant growth and development.

scholarly journals Isolation, Morphological and Biochemical Characterization of Rhizobacteria from Arsenic Contaminated Paddy Soils in Bangladesh: An In vitro Study

2021 ◽  
pp. 41-55
Author(s):  
M. M. Hossain ◽  
G. K. M. M. Rahman ◽  
M. A. M. Akanda ◽  
A. R. M. Solaiman ◽  
M. T. Islam ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Plant Growth ◽  
Growth And Development ◽  
Phosphate Solubilization ◽  
Cellulose Degradation ◽  
Paddy Soils ◽  
Growth Enhancement ◽  
Bacterial Isolates ◽  
Plant Growth And Development ◽  
Iaa Production

Soil-plant–microbes relations within the plant rhizosphere are the determinants of plant and soil health, which is important for soil ecological environment for plant-microbe interactions. Plant growth-promoting rhizobacteria (PGPR) are considered to encourage plant growth and development directly or indirectly in soil. PGPR can demonstrate a diversity of characteristics responsible .for influencing plant growth and development. During this study, Twenty four different bacterial isolates were isolated, and detailed morphological, biochemical, and physiological characterizations of those isolates were accomplished. This experiment was performed with the 24 bacterial isolates to see their gram stain test, KOH test, catalase activity, cellulose degradation capability, in dole acetic acid (IAA) production, and phosphate solubilization activities, and also tested for growth within the different arsenic and salt stress conditions and 37°C temperature. Results revealed that among the rhizobacterial isolates, fifteen bacterial isolates were negative and nine was positive in gram reaction, while some were showed high IAA production ability, phosphate solubility capability, and cellulose degradation capacity within the culture media. The isolates were isolated from paddy soils and a few were characterized by a yellow color, flat elevation, and gram-positive, while some were characterized because of the yellowish color with round colony shape, raised elevation, gram-negative, and every one the isolates were positive in catalase production capacity and phosphate solubilization activity which is able to increase the available phosphorus within the soil for plants and also produced indole acetic acid that may use as a hormone to be used in growth enhancement of plants. Hence, these isolates need to be tested further for their effect on arsenic dynamics at the plant rhizosphere, selection of suitable plant species for the bacterial association, bacterial effect on arsenic uptake by plants, and potentials for field applications for sustainable agriculture.

Mechanisms of ethylene biosynthesis and response in plants

2015 ◽  
Vol 58 ◽  
pp. 61-70 ◽  
Author(s):  
Paul B. Larsen
Keyword(s):  
Plant Growth ◽  
Growth And Development ◽  
Ethylene Biosynthesis ◽  
Unsaturated Hydrocarbon ◽  
Flower Senescence ◽  
Detailed Knowledge ◽  
Plant Growth And Development ◽  
Step Process ◽  
Ethylene Response ◽  
Ethylene Signalling

Ethylene is the simplest unsaturated hydrocarbon, yet it has profound effects on plant growth and development, including many agriculturally important phenomena. Analysis of the mechanisms underlying ethylene biosynthesis and signalling have resulted in the elucidation of multistep mechanisms which at first glance appear simple, but in fact represent several levels of control to tightly regulate the level of production and response. Ethylene biosynthesis represents a two-step process that is regulated at both the transcriptional and post-translational levels, thus enabling plants to control the amount of ethylene produced with regard to promotion of responses such as climacteric flower senescence and fruit ripening. Ethylene production subsequently results in activation of the ethylene response, as ethylene accumulation will trigger the ethylene signalling pathway to activate ethylene-dependent transcription for promotion of the response and for resetting the pathway. A more detailed knowledge of the mechanisms underlying biosynthesis and the ethylene response will ultimately enable new approaches to be developed for control of the initiation and progression of ethylene-dependent developmental processes, many of which are of horticultural significance.

Response of Poinsettia Growth and Development to Ratio of Radiant to Thermal Energy

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 508e-508
Author(s):  
Bin Liu ◽  
Royal D. Heins
Keyword(s):  
Plant Growth ◽  
Thermal Energy ◽  
Growth And Development ◽  
Model Simulation ◽  
Interactive Effect ◽  
Dry Weight ◽  
Plant Spacing ◽  
Plant Growth And Development ◽  
Daily Light Integral ◽  
Highly Correlated

A concept of ratio of radiant to thermal energy (RRT) has been developed to deal with the interactive effect of light and temperature on plant growth and development. This study further confirms that RRT is a useful parameter for plant growth, development, and quality control. Based on greenhouse experiments conducted with 27 treatment combinations of temperature, light, and plant spacing, a model for poinsettia plant growth and development was constructed using the computer program STELLA II. Results from the model simulation with different levels of daily light integral, temperature, and plant spacing showed that the RRT significantly affects leaf unfolding rate when RRT is lower than 0.025 mol/degree-day per plant. Plant dry weight is highly correlated with RRT; it increases linearly as RRT increases.

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