scholarly journals Poplar Allene Oxide Synthase 1 Gene Promoter Drives Rapid and Localized Expression by Wounding

Author(s):  
Bin Lei ◽  
Christopher J. Frost ◽  
Tao Xu ◽  
Joshua R. Herr ◽  
John E. Carlson ◽  
...  

Promoters play critical roles in controlling the transcription of genes and are important as tools to drive heterologous expression for biotechnological applications. In addition to core transcription factor-binding motifs that assist in the binding of RNA polymerases, there are specific nucleotide sequences in a promoter region to allow regulation of gene expression. The allene oxide synthase (AOS) gene family are cytochrome P450s that are responsive to a variety of environmental stress, making them good candidates for the discovery of inducible promoters. Populus AOS homologs separate phylogenetically into two clades. Based on the 19 promoter motifs with significant abundance differences between the two clades, Clade I AOS genes are likely more responsive to hormones, salt, and pathogen, whereas clade II homologs are likely inducible by water stress. In this study, an upstream promoter from a Clade I poplar AOS encoding gene (AOS1) was cloned and used to drive the expression of a ß-glucuronidase (GUS) gene in Arabidopsis. AOS is an essential enzyme in the lipoxygenase pathway that is responsible for the production of many non-volatile oxylipins in plants, including the jasmonates, which are regulatory phytohormones coordinating a variety of biological and stress response functions. Consistent with AOS transcript expression patterns, we found that the poplar AOS1 promoter drives rapid and localized expression by wounding. The study provides insight on the responsive elements in the poplar AOS promoters, but more importantly identifies a strong wound-inducible and localized promoter for future applications.

2000 ◽  
Vol 352 (2) ◽  
pp. 501-509 ◽  
Author(s):  
Alexander N. GRECHKIN ◽  
Lucia S. MUKHTAROVA ◽  
Mats HAMBERG

The in vitro metabolism of [1-14C]linoleate, [1-14C]linolenate and their 9(S)-hydroperoxides was studied in cell-free preparations from tulip (Tulipa gesneriana) bulbs, leaves and flowers. Linoleate and its 9-hydroperoxide were converted by bulb and leaf preparations into three ketols: (12Z)-9-hydroxy-10-oxo-12-octadecadienoic acid (α-ketol), (11E)-10-oxo-13-hydroxy-11-octadecadienoic acid (γ-ketol) and a novel compound, (12Z)-10-oxo-11-hydroxy-12-octadecadienoic acid (10,11-ketol), in the approximate molar proportions of 10:3:1. The corresponding 15,16-dehydro α- and γ-ketols were the main metabolites of [1-14C]linolenate and its 9-hydroperoxide. Thus bulbs and leaves possessed 9-lipoxygenase and allene oxide synthase activities. Incubations with flower preparations gave α-ketol hydro(pero)xides as predominant metabolites. Bulb and leaf preparations possessed a novel enzyme activity, γ-ketol reductase, which reduces γ-ketol to 10-oxo-13-hydroxyoctadecanoic acid (dihydro-γ-ketol) in the presence of NADH. Exogenous linolenate 13(S)-hydroperoxide was converted mostly into chiral (9S,13S)-12-oxo-10-phytodienoate (99.5% optical purity) by bulb preparations, while [1-14C]linolenate was a precursor for ketols only. Thus tulip bulbs possess abundant allene oxide cyclase activity, the substrate for which is linolenate 13(S)-hydroperoxide, even though 13(S)-lipoxygenase products were not detectable in the bulbs. The majority of the cyclase activity was found in the microsomes (105g pellet). Cyclase activity was not found in the other tissues examined, but only in the bulbs. The ketol route of the lipoxygenase pathway, mediated by 9-lipoxygenase and allene oxide synthase activities, has not been detected previously in the vegetative organs of any plant species.


2000 ◽  
Vol 28 (6) ◽  
pp. 851-853 ◽  
Author(s):  
A. N. Grechkin ◽  
L. S. Mukhtarova ◽  
M. Hamberg

The metabolism in vitro of [1-14C]linoleate, [1-14C]linolenate and their 9(S)-hydroperoxides in tulip (Tulipa gesneriana) was found to be under the control of 9-lipoxygenase and allene oxide synthase, and directed towards α-ketol, γ-ketol and the novel compound (12Z)-10-oxo-11-hydroxy- 12-octadecadienoic acid (10,11-ketol). Potent activity of allene oxide cyclase (in bulbs) and a new enzyme, γ-ketol reductase (in bulbs and leaves), was detected. Metabolism in flowers is directed predominantly towards α-ketol hydroperoxide.


2016 ◽  
Vol 85 (1) ◽  
Author(s):  
Emilia Wilmowicz ◽  
Agata Kućko ◽  
Kamil Frankowski ◽  
Barbara Zabrocka-Nowakowska ◽  
Katarzyna Panek ◽  
...  

<em>Allene oxide synthase</em> (<em>AOS</em>) encodes the first enzyme in the lipoxygenase pathway, which is responsible for jasmonic acid (JA) formation. In this study we report the molecular cloning and characterization of <em>InAOS</em> from <em>Ipomoea nil</em>. The full-length gene is composed of 1662 bp and encodes for 519 amino acids. The predicted InAOS contains PLN02648 motif, which is evolutionarily conserved and characteristic for functional enzymatic proteins. We have shown that wounding led to a strong stimulation of the examined gene activity in cotyledons and an increase in JA level, which suggest that this compound may be a modulator of stress responses in <em>I. nil</em>.


2006 ◽  
Vol 281 (51) ◽  
pp. 38981-38988 ◽  
Author(s):  
Bénédicte Bakan ◽  
Mats Hamberg ◽  
Ludivine Perrocheau ◽  
Daniel Maume ◽  
Hélène Rogniaux ◽  
...  

2018 ◽  
Vol 19 (8) ◽  
pp. 2440 ◽  
Author(s):  
Qiyuan Peng ◽  
Ying Zhou ◽  
Yinyin Liao ◽  
Lanting Zeng ◽  
Xinlan Xu ◽  
...  

Jasmonic acid (JA) is reportedly involved in the interaction between insects and the vegetative parts of horticultural crops; less attention has, however, been paid to its involvement in the interaction between insects and the floral parts of horticultural crops. Previously, we investigated the allene oxide synthase 2 (AOS2) gene that was found to be the only JA synthesis gene upregulated in tea (Camellia sinensis) flowers exposed to insect (Thrips hawaiiensis (Morgan)) attacks. In our present study, transient expression analysis in Nicotiana benthamiana plants confirmed that CsAOS2 functioned in JA synthesis and was located in the chloroplast membrane. In contrast to tea leaves, the metabolite profiles of tea flowers were not significantly affected by 10 h JA (2.5 mM) treatment as determined using ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry, and gas chromatography-mass spectrometry. Moreover, JA treatment did not significantly influence ethylene formation in tea flowers. These results suggest that JA in tea flowers may have different functions from JA in tea leaves and other flowers.


2019 ◽  
Vol 70 (13) ◽  
pp. 3373-3378 ◽  
Author(s):  
Edward E Farmer ◽  
Alain Goossens

Plant Science ◽  
2005 ◽  
Vol 169 (1) ◽  
pp. 139-146 ◽  
Author(s):  
Meshack Afitlhile ◽  
Hirotada Fukushige ◽  
Charles McCraken ◽  
David Hildebrand

2019 ◽  
Vol 20 (12) ◽  
pp. 3064 ◽  
Author(s):  
Sachin Rustgi ◽  
Armin Springer ◽  
ChulHee Kang ◽  
Diter von Wettstein ◽  
Christiane Reinbothe ◽  
...  

The channeling of metabolites is an essential step of metabolic regulation in all living organisms. Multifunctional enzymes with defined domains for metabolite compartmentalization are rare, but in many cases, larger assemblies forming multimeric protein complexes operate in defined metabolic shunts. In Arabidopsis thaliana, a multimeric complex was discovered that contains a 13-lipoxygenase and allene oxide synthase (AOS) as well as allene oxide cyclase. All three plant enzymes are localized in chloroplasts, contributing to the biosynthesis of jasmonic acid (JA). JA and its derivatives act as ubiquitous plant defense regulators in responses to both biotic and abiotic stresses. AOS belongs to the superfamily of cytochrome P450 enzymes and is named CYP74A. Another CYP450 in chloroplasts, hydroperoxide lyase (HPL, CYP74B), competes with AOS for the common substrate. The products of the HPL reaction are green leaf volatiles that are involved in the deterrence of insect pests. Both enzymes represent non-canonical CYP450 family members, as they do not depend on O2 and NADPH-dependent CYP450 reductase activities. AOS and HPL activities are crucial for plants to respond to different biotic foes. In this mini-review, we aim to summarize how plants make use of the LOX2–AOS–AOC2 complex in chloroplasts to boost JA biosynthesis over volatile production and how this situation may change in plant communities during mass ingestion by insect pests.


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