T<scp>HE</scp> L<scp>IPOXYGENASE</scp> P<scp>ATHWAY</scp>

Feußner, Ivo; Wasternack, Claus

doi:10.1146/annurev.arplant.53.100301.135248

Cited by 1,286 publications

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“…SvWound2 codes for a putative lipoxygenase; these enzymes catalyse the hydroperoxidation of polyunsaturated fatty acids, the initial step in the biosynthesis of many signalling compounds in plants, including jasmonic acid (Feussner and Wasternack 2002). The second wound-related gene (SvWound3) encodes for a putative serine carboxypeptidase.…”

Section: Discussionmentioning

confidence: 99%

Gene expression in mycorrhizal orchid protocorms suggests a friendly plant–fungus relationship

Perotto

Rodda

Benetti

et al. 2014

Planta

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Main conclusionOrchid mycorrhiza has been often interpreted as an antagonistic relationship. Our data on mycorrhizal protocorms do not support this view as plant defence genes were not induced, whereas some nodulinlike genes were significantly up-regulated.Orchids fully depend on symbiotic interactions with specific soil fungi for seed germination and early development. Germinated seeds give rise to a protocorm, a heterotrophic organ that acquires nutrients, including organic carbon, from the mycorrhizal partner. It has long been debated if this interaction is mutualistic or antagonistic. To investigate the molecular bases of the orchid response to mycorrhizal invasion, we developed a symbiotic in vitro system between Serapias vomeracea, a Mediterranean green meadow orchid, and the rhizoctonia-like fungus Tulasnella calospora. 454 pyrosequencing was used to generate an inventory of plant and fungal genes expressed in mycorrhizal protocorms, and plant genes could be reliably identified with a customized bioinformatic pipeline. A small panel of plant genes was selected and expression was assessed by real-time quantitative PCR in mycorrhizal and non-mycorrhizal protocorm tissues. Among these genes were some markers of mutualistic (e.g. nodulins) as well as antagonistic (e.g. pathogenesis-related and wound/stress-induced) genes. None of the pathogenesis or wound/stress-related genes were significantly up-regulated in mycorrhizal tissues, suggesting that fungal colonization does not trigger strong plant defence responses. In addition, the highest expression fold change in mycorrhizal tissues was found for a nodulin-like gene similar to the plastocyanin domaincontaining ENOD55. Another nodulin-like gene significantly more expressed in the symbiotic tissues of mycorrhizal protocorms was similar to a sugar transporter of the SWEET family. Two genes coding for mannose-binding lectins were significantly up-regulated in the presence of the mycorrhizal fungus, but their role in the symbiosis is unclear.

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Section: Discussionmentioning

confidence: 99%

Gene expression in mycorrhizal orchid protocorms suggests a friendly plant–fungus relationship

Perotto

Rodda

Benetti

et al. 2014

Planta

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“…HPOs are key intermediates in the LOX pathway; they can be converted enzymatically to a variety of compounds called oxylipins. At least seven enzymatic pathways use HPOs as substrates: hydroperoxide lyase that cleaves HPO into aldehydes and oxo-acids, allene oxide synthase that forms precursors of a-and g-ketols and jasmonic acid, peroxygenase that causes epoxidation and reduction of HPO, epoxy alcohol synthase that transforms HPO into epoxy hydroxy fatty acids, the reductase pathway that reduces HPO into hydroxyderivatives, divinyl ether synthase (DES) that produces divinyl ethers, and finally, LOX that acts on HPO to give keto derivatives [2].…”

Section: Introductionmentioning

confidence: 99%

Lipid and oxylipin profiles during aging and sprout development in potato tubers (Solanum tuberosum L.)

Fauconnier

2003

Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biolog

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Potato tubers (Solanum tuberosum L. cv Bintje) were stored at 20 jC for 210 days without desprouting to study the lipoxygenase pathway during aging. After 15 days of storage, potato tubers sprouted, while after 45 -60 days, apical dominance was lost and multiple sprouts developed. Analysis of the fatty acid hydroperoxides (HPOs) revealed that 9-S-hydroperoxide of linoleic acid (9-HPOD) was the main oxylipin formed. Between 45 and 60 days of storage, increases in the levels of 9-HPOD and colneleic acid were observed. Analysis of phospholipids and galactolipids by electrospray ionisation tandem mass spectrometry (ESI-MS/MS) showed that a decrease in the levels of phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylinositol (PI), digalactosyldiacylglycerol (DGDG), and monogalactosyldiacylglycerol (MGDG) occurred between 0 and 45 days of aging. The decrease in the amount of linoleic acid in complex lipids correlates well with the amount of 9-HPOD and colneleic acid produced. D

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“…Allene oxide synthase activity in plants is carried out by cytochrome P450 enzymes in the CYP74 group of atypical P450s (2). Enzymes in this family catalyze isomerizations of fatty acid hydroperoxides without requiring reductants or molecular oxygen (2,9).…”

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confidence: 99%

Role of Radical Formation at Tyrosine 193 in the Allene Oxide Synthase Domain of a Lipoxygenase−AOS Fusion Protein from Coral

Katsir

Seavy

et al. 2003

Biochemistry

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Coral allene oxide synthase (cAOS), a fusion protein with 8R-lipoxygenase in Plexaura homomalla, is a hemoprotein with sequence similarity to catalases. cAOS reacts rapidly with the oxidant peracetic acid to form heme compound I and intermediate II. Concomitantly, an electron paramagnetic resonance (EPR) signal with tyrosyl radical-like features, centered at a g-value of 2.004-2.005, is formed. The radical is identified as tyrosyl by changes in EPR spectra when deuterated tyrosine is incorporated in cAOS. The radical location in cAOS is determined by mutagenesis of Y193 and Y209. Upon oxidation, native cAOS and mutant Y209F exhibit the same radical spectrum, but no significant tyrosine radical forms in mutant Y193H, implicating Y193 as the radical site in native cAOS. Estimates of the side chain torsion angles for the radical at Y193, based on the β-proton isotropic EPR hyperfine splitting, A iso , are θ 1 = 21 to 30° and θ 2 = −99 to −90°. The results show that cAOS can cleave nonsubstrate hydroperoxides by a heterolytic path, although a homolytic course is likely taken in converting the normal substrate, 8R-hydroperoxyeicosatetraenoic acid (8R-HpETE), to product. Coral AOS achieves specificity for the allene oxide formed by selection of the homolytic pathway normally, while it inactivates by the heterolytic path with nonoptimal substrates. Accordingly, with the nonoptimal substrate, 13R-hydroperoxyoctadecadienoic acid (13R-HpODE), mutant Y193H is inactivated after turning over significantly fewer substrate molecules than required to inactivate native cAOS or the Y209F mutant because it cannot absorb oxidizing equivalents by forming a radical at Y193. Polyunsaturated fatty acids (PUFAs) 1 are rapidly converted to cell signaling molecules in multistep syntheses involving an initial lipoxygenase or prostaglandin synthase step, followed by further enzymatic conversions (1-3). These multistep syntheses are regulated by localization of the enzymes in subcellular compartments and by protein-protein associations. Examples include synthesis of leukotriene C 4 at the nuclear envelope of leukocytes (4) and synthesis of jasmonic acid by steps which are thought to begin in chloroplasts and to be completed in peroxisomes of green plant cells (5). A fusion protein identified in the coral Plexaura homomalla represents a third mode of regulation, in which an N-terminal catalaselike domain is fused to an 8R-lipoxygenase domain (6). The N-terminal domain (44 kDa) has allene oxide synthase (cAOS) activity with the 8R-hydroperoxide of arachidonic acid (8R- † This research was supported by National Institutes of Health Grant GM36232 (to B.J.G.).* To whom correspondence should be addressed. Phone: (850) 644-8547. Fax: (850) 644-8547. E-mail: gaffney@bio.fsu.edu.. ‡ These authors contributed equally.1 Abbreviations: cAOS, coral allene oxide synthase; BLC, bovine liver catalase; BSA, bovine serum albumin; CYP, cytochrome P450; DES, divinyl ether synthase; EPR, electron paramagnetic resonance; 8R-HpETE, 8R-hydroperoxy-9E,11Z-ei...

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THE LIPOXYGENASE PATHWAY

Cited by 1,286 publications

References 132 publications

Gene expression in mycorrhizal orchid protocorms suggests a friendly plant–fungus relationship

Gene expression in mycorrhizal orchid protocorms suggests a friendly plant–fungus relationship

Lipid and oxylipin profiles during aging and sprout development in potato tubers (Solanum tuberosum L.)

Role of Radical Formation at Tyrosine 193 in the Allene Oxide Synthase Domain of a Lipoxygenase−AOS Fusion Protein from Coral

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