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Dang X, Hu C, Shen D, Chen Z, Hu S. A novel electrochemical method for determination of cis-jasmone based on enhancement effect of cetyltrimethylammonium bromide. J Electroanal Chem (Lausanne) 2011. [DOI: 10.1016/j.jelechem.2011.03.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Hoffmann M, Hentrich M, Pollmann S. Auxin-oxylipin crosstalk: relationship of antagonists. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2011; 53:429-45. [PMID: 21658177 DOI: 10.1111/j.1744-7909.2011.01053.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Stephan Pollmann (Corresponding author) Phytohormones regulate a wide array of developmental processes throughout the life cycle of plants. Herein, the various plant hormones may interact additively, synergistically, or antagonistically. By their cooperation they create a delicate regulatory network whose net output largely depends on the action of specific phytohormone combinations rather than on the independent activities of separate hormones. While most classical studies of plant hormonal control have focused mainly on the action of single hormones or on the synergistic interaction of hormones in regulating various developmental processes, recent work is beginning to shed light on the crosstalk of nominally antagonistic plant hormones, such as gibberellins and auxins with oxylipins or abscisic acid. In this review, we summarize our current understanding of how two of the first sight antagonistic plant hormones, i.e. auxins and oxylipins, interact in controlling plant responses and development.
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Affiliation(s)
- Maik Hoffmann
- Centro de Biotecnología y Genómica de Plantas (U.P.M. - I.N.I.A.) Parque Científico y Tecnológico de la U.P.M., Campus de Montegancedo, Crta., Pozuelo de Alarcón, Madrid, Spain
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Singh AK, Fu DQ, El-Habbak M, Navarre D, Ghabrial S, Kachroo A. Silencing genes encoding omega-3 fatty acid desaturase alters seed size and accumulation of Bean pod mottle virus in soybean. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2011; 24:506-15. [PMID: 21117867 DOI: 10.1094/mpmi-09-10-0201] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Omega-3 fatty acid desaturase (FAD3)-catalyzed conversion of linoleic acid to linolenic acid (18:3) is an important step for the biosynthesis of fatty acids as well as the phytohormone jasmonic acid (JA) in plants. We report that silencing three microsomal isoforms of GmFAD3 enhanced the accumulation of Bean pod mottle virus (BPMV) in soybean. The GmFAD3-silenced plants also accumulated higher levels of JA, even though they contained slightly reduced levels of 18:3. Consequently, the GmFAD3-silenced plants expressed JA-responsive pathogenesis-related genes constitutively and exhibited enhanced susceptibility to virulent Pseudomonas syringae. Increased accumulation of BPMV in GmFAD3-silenced plants was likely associated with their JA levels, because exogenous JA application also increased BPMV accumulation. The JA-derived increase in BPMV levels was likely not due to repression of salicylic acid (SA)-derived signaling because the GmFAD3-silenced plants were enhanced in SA-dependent defenses. Furthermore, neither exogenous SA application nor silencing the SA-synthesizing phenylalanine ammonia lyase gene altered BPMV levels in soybean. In addition to the altered defense responses, the GmFAD3-silenced plants also produced significantly larger and heavier seed. Our results indicate that loss of GmFAD3 enhances JA accumulation and, thereby, susceptibility to BPMV in soybean.
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Affiliation(s)
- Ajay Kumar Singh
- Department of Plant Pathology, University of Kentucky, Lexington, USA
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Wei J, Kang L. Roles of (Z)-3-hexenol in plant-insect interactions. PLANT SIGNALING & BEHAVIOR 2011; 6:369-71. [PMID: 21346418 PMCID: PMC3142417 DOI: 10.4161/psb.6.3.14452] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Accepted: 12/10/2010] [Indexed: 05/18/2023]
Abstract
Green leaf C6-volatiles are among the most important herbivore-induced plant volatiles (HIPVs). They play important roles in mediating the behavior of herbivores and their natural enemies, and in triggering the plant-plant communication to prevent further attacks. Recently, wound-induced ubiquitous (Z)-3-hexenol, a C6-alcohol synthesized in the lipoxygenase/HPL pathway, was proved to be the most important infochemical for the herbivore repellence/attraction and natural enemy attraction in tritrophic interactions, as well as for the induction of gene expression in neighboring unattacked plants. In spite of the conflict functions of (Z)-3-hexenol in direct and indirect plant defenses, its positive roles in the indirect defense and the priming effect are consistent. Therefore, this compound can be used to develop novel insect pest control strategies.
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Affiliation(s)
- Jianing Wei
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, P R China
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Abstract
Phospholipase A(1) (PLA(1)) is an enzyme that hydrolyzes phospholipids and produces 2-acyl-lysophospholipids and fatty acids. This lipolytic activity is conserved in a wide range of organisms but is carried out by a diverse set of PLA(1) enzymes. Where their function is known, PLA(1)s have been shown to act as digestive enzymes, possess central roles in membrane maintenance and remodeling, or regulate important cellular mechanisms by the production of various lysophospholipid mediators, such as lysophosphatidylserine and lysophosphatidic acid, which in turn have multiple biological functions.
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Affiliation(s)
- Gregory S. Richmond
- Agilent Technologies, Molecular Separations, Santa Clara, CA 95051, USA; E-Mail:
| | - Terry K. Smith
- Centre for Biomolecular Sciences, The North Haugh, The University, St. Andrews, KY16 9ST, Scotland, UK
- To whom correspondence should be addressed; E-Mail: ; Tel.: +44-1334-463412; Fax: +44-1334-462595
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Wei J, Wang L, Zhao J, Li C, Ge F, Kang L. Ecological trade-offs between jasmonic acid-dependent direct and indirect plant defences in tritrophic interactions. THE NEW PHYTOLOGIST 2011; 189:557-67. [PMID: 21039561 PMCID: PMC3039750 DOI: 10.1111/j.1469-8137.2010.03491.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Accepted: 08/24/2010] [Indexed: 05/21/2023]
Abstract
Recent studies on plants genetically modified in jasmonic acid (JA) signalling support the hypothesis that the jasmonate family of oxylipins plays an important role in mediating direct and indirect plant defences. However, the interaction of two modes of defence in tritrophic systems is largely unknown. In this study, we examined the preference and performance of a herbivorous leafminer (Liriomyza huidobrensis) and its parasitic wasp (Opius dissitus) on three tomato genotypes: a wild-type (WT) plant, a JA biosynthesis (spr2) mutant, and a JA-overexpression 35S::prosys plant. Their proteinase inhibitor production and volatile emission were used as direct and indirect defence factors to evaluate the responses of leafminers and parasitoids. Here, we show that although spr2 mutant plants are compromised in direct defence against the larval leafminers and in attracting parasitoids, they are less attractive to adult flies compared with WT plants. Moreover, in comparison to other genotypes, the 35S::prosys plant displays greater direct and constitutive indirect defences, but reduced success of parasitism by parasitoids. Taken together, these results suggest that there are distinguished ecological trade-offs between JA-dependent direct and indirect defences in genetically modified plants whose fitness should be assessed in tritrophic systems and under natural conditions.
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Affiliation(s)
- Jianing Wei
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of SciencesBeijing 100080, China
| | - Lizhong Wang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of SciencesBeijing 100080, China
| | - Jiuhai Zhao
- State Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology of the Chinese Academy of SciencesBeijing 100101, China
| | - Chuanyou Li
- State Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology of the Chinese Academy of SciencesBeijing 100101, China
| | - Feng Ge
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of SciencesBeijing 100080, China
| | - Le Kang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of SciencesBeijing 100080, China
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Lagarde M. Oxygenated metabolites of polyunsaturated fatty acids: Formation and function in blood and vascular cells. EUR J LIPID SCI TECH 2010. [DOI: 10.1002/ejlt.201000045] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Liu F, Jiang H, Ye S, Chen WP, Liang W, Xu Y, Sun B, Sun J, Wang Q, Cohen JD, Li C. The Arabidopsis P450 protein CYP82C2 modulates jasmonate-induced root growth inhibition, defense gene expression and indole glucosinolate biosynthesis. Cell Res 2010; 20:539-52. [PMID: 20354503 DOI: 10.1038/cr.2010.36] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Jasmonic acid (JA) is a fatty acid-derived signaling molecule that regulates a broad range of plant defense responses against herbivores and some microbial pathogens. Molecular genetic studies have established that JA also performs a critical role in several aspects of plant development. Here, we describe the characterization of the Arabidopsis mutant jasmonic acid-hypersensitive1-1 (jah1-1), which is defective in several aspects of JA responses. Although the mutant exhibits increased sensitivity to JA in root growth inhibition, it shows decreased expression of JA-inducible defense genes and reduced resistance to the necrotrophic fungus Botrytis cinerea . Gene cloning studies indicate that these defects are caused by a mutation in the cytochrome P450 protein CYP82C2. We provide evidence showing that the compromised resistance of the jah1-1 mutant to B . cinerea is accompanied by decreased expression of JA-induced defense genes and reduced accumulation of JA-induced indole glucosinolates (IGs). Conversely, the enhanced resistance to B. cinerea in CYP82C2-overexpressing plants is accompanied by increased expression of JA-induced defense genes and elevated levels of JA-induced IGs. We demonstrate that CYP82C2 affects JA-induced accumulation of the IG biosynthetic precursor tryptophan (Trp), but not the JA-induced IAA or pathogen-induced camalexin. Together, our results support a hypothesis that CYP82C2 may act in the metabolism of Trp-derived secondary metabolites under conditions in which JA levels are elevated. The jah1-1 mutant should thus be important in future studies toward understanding the mechanisms underlying the complexity of JA-mediated differential responses, which are important for plants to adapt their growth to the ever-changing environments.
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Affiliation(s)
- Fang Liu
- State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing 100101, China
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Santner A, Estelle M. The ubiquitin-proteasome system regulates plant hormone signaling. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 61:1029-40. [PMID: 20409276 PMCID: PMC3066055 DOI: 10.1111/j.1365-313x.2010.04112.x] [Citation(s) in RCA: 264] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Plants utilize the ubiquitin-proteasome system (UPS) to modulate nearly every aspect of growth and development. Ubiquitin is covalently attached to target proteins through the action of three enzymes known as E1, E2, and E3. The ultimate outcome of this post-translational modification depends on the nature of the ubiquitin linkage and the extent of polyubiquitination. In most cases, ubiquitination results in degradation of the target protein in the 26S proteasome. During the last 10 years it has become clear that the UPS plays a prominent regulatory role in hormone biology. E3 ubiquitin ligases in particular actively participate in hormone perception, de-repression of hormone signaling pathways, degradation of hormone specific transcription factors, and regulation of hormone biosynthesis. It is certain that additional functions will be discovered as more of the nearly 1200 potential E3s in plants are elucidated.
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Affiliation(s)
- Aaron Santner
- Molecular Kinetics, Inc., 6201 La Pas Trail, Suite 160, Indianapolis, IN 46268, USA
| | - Mark Estelle
- University of California San Diego, Section of Cell and Developmental Biology, 9500 Gilman Drive, La Jolla, CA 9209, USA
- For correspondence (fax +858 534 7108; )
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Glauser G, Boccard J, Rudaz S, Wolfender JL. Mass spectrometry-based metabolomics oriented by correlation analysis for wound-induced molecule discovery: identification of a novel jasmonate glucoside. PHYTOCHEMICAL ANALYSIS : PCA 2010; 21:95-101. [PMID: 19743069 DOI: 10.1002/pca.1155] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
INTRODUCTION Jasmonates are members of the oxylipin family involved in various plant regulatory processes, particularly in the response to biotic and abiotic stresses. They are present in very low amounts in wounded plants, which complicates their detection within complex plant extracts. Therefore, advanced analytical methods are needed for the profiling and characterisation of novel jasmonate derivatives. OBJECTIVE To use metabolomics to search for original wound-induced metabolites belonging to the jasmonate family. METHODOLOGY Numerous Arabidopsis specimens harvested at various time points after wounding were analysed by ultra-high pressure liquid chromatography coupled to time-of-flight mass spectrometry (UHPLC/TOFMS). A correlation analysis based on kinetic profile similarities with known jasmonates was applied to find wound-induced molecules having a potential role in defence signalling. Their characterisation was performed by tandem mass spectrometry and capillary nuclear magnetic resonance spectroscopy. RESULTS The statistical data treatment highlighted several previously reported jasmonates as well as a new glucoside derivative of the jasmonate 3-oxo-2-(2Z-pentenyl) cyclopentane-1-butyric acid (OPC-4). The monitoring of its kinetics in response to wounding revealed a delayed accumulation compared to the profile of OPC-4. This suggests an inactivation or elimination of OPC-4 through the formation of a polar glucosylated metabolite. CONCLUSION The metabolomic approach developed has proved useful in the discovery of original jasmonates synthesised in response to plant wounding.
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Affiliation(s)
- Gaetan Glauser
- School of Pharmaceutical Sciences, EPGL, University of Geneva, University of Lausanne, 30, quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
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Fang Y, Xie K, Hou X, Hu H, Xiong L. Systematic analysis of GT factor family of rice reveals a novel subfamily involved in stress responses. Mol Genet Genomics 2009; 283:157-69. [PMID: 20039179 DOI: 10.1007/s00438-009-0507-x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2009] [Accepted: 12/11/2009] [Indexed: 01/25/2023]
Abstract
GT factors constitute a plant-specific transcription factor family with a conserved trihelix DNA-binding domain. In this study, comprehensive sequence analysis suggested that 26 putative GT factors exist in rice. Phylogenetic analysis revealed three distinctive subfamilies (GTalpha, GTbeta, and GTgamma) of plant GT factors and each subfamily has a unique composition of predicted motifs. We characterized the OsGTgamma-1 gene, a typical member of the GTgamma subfamily in rice. This gene encodes a protein containing a conserved trihelix domain, and the OsGTgamma-1:GFP fusion protein was targeted to nuclei of rice cells. The transcript level of OsGTgamma-1 was strongly induced by salt stress and slightly induced by drought and cold stresses and abscisic acid treatment. Two other members of the GTgamma subfamily, OsGTgamma-2 and OsGTgamma-3, were also induced by most of the abiotic stresses. These results suggested that the genes of the GTgamma subfamily in rice may be involved in stress responses. A homozygous mutant osgtgamma-1 (with T-DNA inserted in the promoter region of OsGTgamma-1) showed more sensitive to salt stress than wild-type rice. Overexpression of OsGTgamma-1 in rice enhanced salt tolerance at the seedling stage. This evidence suggests that the OsGTgamma subfamily may participate in the regulation of stress tolerance in rice.
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Affiliation(s)
- Yujie Fang
- National Key Laboratory of Crop Genetic Improvement, National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, 430070, Wuhan, China
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63
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Fattorini L, Falasca G, Kevers C, Rocca LM, Zadra C, Altamura MM. Adventitious rooting is enhanced by methyl jasmonate in tobacco thin cell layers. PLANTA 2009; 231:155-68. [PMID: 19885676 DOI: 10.1007/s00425-009-1035-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2009] [Accepted: 10/01/2009] [Indexed: 05/04/2023]
Abstract
Adventitious roots (ARs) are induced by auxins. Jasmonic acid (JA) and methyl jasmonate (MeJA) are also plant growth regulators with many effects on development, but their role on ARs needs investigation. To this aim, we analyzed AR formation in tobacco thin cell layers (TCLs) cultured with 0.01-10 microM MeJA, either under root-inductive conditions, i.e., on medium containing 10 microM indole-3-butyric acid (IBA) and 0.1 microM kinetin, or without hormones. The explants were excised from the cultivars Samsun, Xanthii and Petite Havana, and from genotypes with altered AR-forming ability in response to auxin, namely the non-rooting rac mutant and the over-rooting Agrobacterium rhizogenes rolB transgenic line. Results show that NtRNR1 (G1/S) and Ntcyc29 (G2/M) gene activity, cell proliferation and meristemoid formation were stimulated in hormone-cultured TCLs by submicromolar MeJA concentrations. The meristemoids developed either into ARs and xylogenic nodules, or into xylogenic nodules only (rac TCLs). MeJA-induced meristemoid over-production characterized rolB TCLs. No rooting or xylogenesis occurred under hormone-free conditions, independently of MeJA and genotype. Endogenous JA progressively (days 1-4) increased in hormone-cultured TCLs in the absence of MeJA. JA levels were enhanced by 0.1 microM MeJA, on both days 1 and 4. Endogenous IBA was the only auxin detected, both in the free form and as IBA-glucose. Free IBA increased up to day 2, remaining constant thereafter (day 4). Its level was enhanced by 0.1 microM MeJA only on day 1, while IBA conjugation was not affected by MeJA. Taken together, these results show that an interplay between jasmonates and auxins regulates AR formation and xylogenesis in tobacco TCLs.
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Affiliation(s)
- Laura Fattorini
- Dipartimento di Biologia Vegetale, Sapienza Università di Roma, P.le A. Moro 5, 00185, Rome, Italy
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Brioudes F, Joly C, Szécsi J, Varaud E, Leroux J, Bellvert F, Bertrand C, Bendahmane M. Jasmonate controls late development stages of petal growth in Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2009; 60:1070-80. [PMID: 19765234 DOI: 10.1111/j.1365-313x.2009.04023.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
In Arabidopsis, four homeotic gene classes, A, B, C and E, are required for the patterning of floral organs. However, very little is known about how the activity of these master genes is translated into regulatory processes leading to specific growth patterns and the formation of organs with specific shapes and sizes. Previously we showed that the transcript variant BPEp encodes a bHLH transcription factor that is involved in limiting petal size by controlling post-mitotic cell expansion. Here we show that the phytohormone jasmonate is required for control of BPEp expression. Expression of BPEp was negatively regulated in opr3 mutant flowers that are deficient in jasmonate synthesis. Moreover, the expression of BPEp was restored in opr3 flowers following exogenous jasmonate treatments. Expression of the second transcript variant BPEub, which originates from the same gene as BPEp via an alternative splicing event, was not affected, indicating that BPEp accumulation triggered by jasmonate occurs at the post-transcriptional level. Consistent with these data, opr3 exhibited an increase in petal size as a result of increased cell size, as well as a modified vein pattern, phenotypes that are similar to those of the bpe-1 mutant. Furthermore, exogenous treatments with jasmonate rescued petal phenotypes associated with loss of function of OPR3. Our data demonstrate that jasmonate signaling downstream of OPR3 is involved in the control of cell expansion and in limiting petal size, and that BPEp is a downstream target that functions as a component mediating jasmonate signaling during petal growth.
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Affiliation(s)
- Florian Brioudes
- Reproduction et Développement des Plantes, Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique-Université Lyon 1-ENSL, IFR128 BioSciences, Ecole Normale Supérieure, 46 allée d'Italie, 69364 Lyon Cedex 07, France
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Bannenberg G, Martínez M, Rodríguez MJ, López MA, Ponce de León I, Hamberg M, Castresana C. Functional analysis of alpha-DOX2, an active alpha-dioxygenase critical for normal development in tomato plants. PLANT PHYSIOLOGY 2009; 151:1421-32. [PMID: 19759339 PMCID: PMC2773050 DOI: 10.1104/pp.109.145094] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2009] [Accepted: 09/14/2009] [Indexed: 05/20/2023]
Abstract
Plant alpha-dioxygenases initiate the synthesis of oxylipins by catalyzing the incorporation of molecular oxygen at the alpha-methylene carbon atom of fatty acids. Previously, alpha-DOX1 has been shown to display alpha-dioxygenase activity and to be implicated in plant defense. In this study, we investigated the function of a second alpha-dioxygenase isoform, alpha-DOX2, in tomato (Solanum lycopersicum) and Arabidopsis (Arabidopsis thaliana). Recombinant Slalpha-DOX2 and Atalpha-DOX2 proteins catalyzed the conversion of a wide range of fatty acids into 2(R)-hydroperoxy derivatives. Expression of Slalpha-DOX2 and Atalpha-DOX2 was found in seedlings and increased during senescence induced by detachment of leaves. In contrast, microbial infection, earlier known to increase the expression of alpha-DOX1, did not alter the expression of Slalpha-DOX2 or Atalpha-DOX2. The tomato mutant divaricata, characterized by early dwarfing and anthocyanin accumulation, carries a mutation at the Slalpha-DOX2 locus and was chosen for functional studies of alpha-DOX2. Transcriptional changes in such mutants showed the up-regulation of genes playing roles in lipid and phenylpropanoid metabolism, the latter being in consonance with the anthocyanin accumulation. Transgenic expression of Atalpha-DOX2 and Slalpha-DOX2 in divaricata partially complemented the compromised phenotype in mature plants and fully complemented it in seedlings, thus indicating the functional exchangeability between alpha-DOX2 from tomato and Arabidopsis. However, deletion of Atalpha-DOX2 in Arabidopsis plants did not provoke any visible phenotypic alteration indicating that the relative importance of alpha-DOX2 in plant physiology is species specific.
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Sears DD, Miles PD, Chapman J, Ofrecio JM, Almazan F, Thapar D, Miller YI. 12/15-lipoxygenase is required for the early onset of high fat diet-induced adipose tissue inflammation and insulin resistance in mice. PLoS One 2009; 4:e7250. [PMID: 19787041 PMCID: PMC2746280 DOI: 10.1371/journal.pone.0007250] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2009] [Accepted: 08/03/2009] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Recent understanding that insulin resistance is an inflammatory condition necessitates searching for genes that regulate inflammation in insulin sensitive tissues. 12/15-lipoxygenase (12/15LO) regulates the expression of proinflammatory cytokines and chemokines and is implicated in the early development of diet-induced atherosclerosis. Thus, we tested the hypothesis that 12/15LO is involved in the onset of high fat diet (HFD)-induced insulin resistance. METHODOLOGY/PRINCIPAL FINDINGS Cells over-expressing 12/15LO secreted two potent chemokines, MCP-1 and osteopontin, implicated in the development of insulin resistance. We assessed adipose tissue inflammation and whole body insulin resistance in wild type (WT) and 12/15LO knockout (KO) mice after 2-4 weeks on HFD. In adipose tissue from WT mice, HFD resulted in recruitment of CD11b(+), F4/80(+) macrophages and elevated protein levels of the inflammatory markers IL-1beta, IL-6, IL-10, IL-12, IFNgamma, Cxcl1 and TNFalpha. Remarkably, adipose tissue from HFD-fed 12/15LO KO mice was not infiltrated by macrophages and did not display any increase in the inflammatory markers compared to adipose tissue from normal chow-fed mice. WT mice developed severe whole body (hepatic and skeletal muscle) insulin resistance after HFD, as measured by hyperinsulinemic euglycemic clamp. In contrast, 12/15LO KO mice exhibited no HFD-induced change in insulin-stimulated glucose disposal rate or hepatic glucose output during clamp studies. Insulin-stimulated Akt phosphorylation in muscle tissue from HFD-fed mice was significantly greater in 12/15LO KO mice than in WT mice. CONCLUSIONS These results demonstrate that 12/15LO mediates early stages of adipose tissue inflammation and whole body insulin resistance induced by high fat feeding.
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Affiliation(s)
- Dorothy D Sears
- Division of Endocrinology and Metabolism, Department of Medicine, University of California San Diego, La Jolla, California, United States of America.
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Göbel C, Feussner I. Methods for the analysis of oxylipins in plants. PHYTOCHEMISTRY 2009; 70:1485-503. [PMID: 19735927 DOI: 10.1016/j.phytochem.2009.07.040] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2009] [Revised: 07/14/2009] [Accepted: 07/16/2009] [Indexed: 05/08/2023]
Abstract
Plant oxylipins comprise a highly diverse and complex class of molecules that are derived from lipid oxidation. The initial oxidation of unsaturated fatty acids may either occur by enzymatic or chemical reactions. A large variety of oxylipin classes are generated by an array of alternative reactions further converting hydroperoxy fatty acids. The structural diversity of oxylipins is further increased by their occurrence either as free fatty acid derivatives or as esters in complex lipids. Lipid peroxidation is common to all biological systems, appearing in developmentally regulated processes and as a response to environmental changes. The oxylipins formed may perform various biological roles; some of them have signaling functions. In order to elucidate the roles of oxylipins in a given biological context, comprehensive analytical assays are available for determining the oxylipin profiles of plant tissues. This review summarizes indirect methods to estimate the general peroxidation state of a sample and more sophisticated techniques for the identification, structure determination and quantification of oxylipins.
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Affiliation(s)
- Cornelia Göbel
- Georg-August-University, Albrecht-von-Haller-Institute for Plant Science, Department of Plant Biochemistry, D-37077 Göttingen, Germany
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Browse J. The power of mutants for investigating jasmonate biosynthesis and signaling. PHYTOCHEMISTRY 2009; 70:1539-46. [PMID: 19740496 DOI: 10.1016/j.phytochem.2009.08.004] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2009] [Revised: 08/04/2009] [Accepted: 08/05/2009] [Indexed: 05/18/2023]
Abstract
Mutant analysis includes approaches that range from traditional screening of mutant populations (forward genetics), to identifying mutations in known genes (reverse genetics), to examining the effects of site-specific mutations that encode modified proteins. All these methodologies have been applied to study jasmonate synthesis and signaling, and their use has led to important discoveries. The fad3 fad7 fad8 mutant of Arabidopsis, and other mutants defective in jasmonate synthesis, revealed the roles of jasmonate in flower development and plant defense against necrotrophic fungal pathogens. The coi1 mutant identified the F-box protein that is now known to be the receptor for jasmonoyl-isoleucine, the active form of jasmonate hormone. Investigations of how JASMONATE-ZIM DOMAIN (JAZ) proteins bind to COI1 and facilitate jasmonate perception have relied on the jai3 mutant, on JAZDeltaJas constructs, and on site-specific mutations in the Jas and ZIM domains of these proteins.
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Affiliation(s)
- John Browse
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340, USA.
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69
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Schaller A, Stintzi A. Enzymes in jasmonate biosynthesis - structure, function, regulation. PHYTOCHEMISTRY 2009; 70:1532-8. [PMID: 19703696 DOI: 10.1016/j.phytochem.2009.07.032] [Citation(s) in RCA: 250] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2009] [Revised: 07/27/2009] [Accepted: 07/28/2009] [Indexed: 05/20/2023]
Abstract
Jasmonates are a growing class of lipid-derived signaling molecules with diverse functions ranging from the initiation of biotic and abiotic stress responses to the regulation of plant growth and development. Jasmonate biosynthesis originates from polyunsaturated fatty acids in chloroplast membranes. In a first lipoxygenase-catalyzed reaction molecular oxygen is introduced to yield their 13-hydroperoxy derivatives. These fatty acid hydroperoxides are converted by allene oxide synthase and allene oxide cyclase to 12-oxophytodienoic acid (OPDA) and dinor-OPDA, i.e. the first cyclic intermediates of the pathway. In the subsequent step, the characteristic cyclopentanone ring structure of jasmonates is established by OPDA reductase. Until recently, jasmonic acid has been viewed as the end product of the pathway and as the bioactive hormone. It becomes increasingly clear, however, that biological activity extends to and may even differ between the various jasmonic acid metabolites and conjugates as well as its biosynthetic precursors. It has also become clear that oxygenated fatty acids give rise to a vast variety of bioactive compounds including but not limited to jasmonates. Recent insights into the structure, function, and regulation of the enzymes involved in jasmonate biosynthesis help to explain how this variety is generated while specificity is maintained.
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Affiliation(s)
- Andreas Schaller
- Institute of Plant Physiology and Biotechnology, University of Hohenheim, D-70599 Stuttgart, Germany.
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70
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Koo AJK, Gao X, Jones AD, Howe GA. A rapid wound signal activates the systemic synthesis of bioactive jasmonates in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2009; 59:974-86. [PMID: 19473329 DOI: 10.1111/j.1365-313x.2009.03924.x] [Citation(s) in RCA: 269] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Jasmonic acid (JA) and its biologically active derivatives (bioactive JAs) perform a critical role in regulating plant responses to wound stress. The perception of bioactive JAs by the F-box protein COI1 triggers the SCF(COI1)/ubiquitin-dependent degradation of JASMONATE ZIM-DOMAIN (JAZ) proteins that repress the expression of JA-response genes. JA is required for many wound-inducible systemic defense responses, but little is known about the role of the hormone in long-distance signal relay between damaged and undamaged leaves. Here, we show that the wounding of Arabidopsis thaliana leaves results in the rapid (<5 min) accumulation of jasmonoyl-l-isoleucine (JA-Ile), the bioactive form of JA, in leaves distal to the wound site. The rapid systemic increase in JA-Ile preceded the onset of early transcriptional responses, and was associated with JAZ degradation. Wound-induced systemic production of JA-Ile required the JA biosynthetic enzyme 12-oxo-phytodienoic acid (OPDA) reductase 3 (OPR3) in undamaged responding leaves, but not in wounded leaves, and was largely dependent on the JA-conjugating enzyme JAR1. Interestingly, the wound-induced synthesis of JA/JA-Ile in systemic leaves was correlated with a rapid decline in OPDA levels. These results are consistent with a model in which a rapidly transmitted wound signal triggers the systemic synthesis of JA, which, upon conversion to JA-Ile, activates the expression of early response genes by the SCF(COI1)/JAZ pathway.
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Affiliation(s)
- Abraham J K Koo
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
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71
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Davis SJ. Integrating hormones into the floral-transition pathway of Arabidopsis thaliana. PLANT, CELL & ENVIRONMENT 2009; 32:1201-10. [PMID: 19302104 DOI: 10.1111/j.1365-3040.2009.01968.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The transition from vegetative to reproductive growth is a major phase change in angiosperms. In annual plants such as Arabidopsis thaliana (Arabidopsis), this change is irreversible, and as such, the regulation of its timing must be tightly controlled. Plant hormone (phytohormone) signalling is known to regulate suites of morphogenic processes in Arabidopsis a role in flowering-time control is starting to emerge as one key-controlling step. This review focuses on experimental evidence in the Arabidopsis that both classical and newly described phytohormones serve within the signal network leading to a reproductive phase transition, as both positive and repressive elements, depending on the phytohormone and growth conditions. Examples of genetic and pharmacological experiments that implicate phytohormones as components of the floral-timing syndrome will be described. I hope that this review will serve as a primer for future research on the mechanisms of action for each respective phytohormone on the floral transition in Arabidopsis, and lead to further experimentation on the crosstalk that likely bridges between them.
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Affiliation(s)
- Seth J Davis
- Max Planck Institute for Plant Breeding Research, Carl von Linne Weg 10, Cologne D-50829, Germany.
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72
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Böttcher C, Pollmann S. Plant oxylipins: plant responses to 12-oxo-phytodienoic acid are governed by its specific structural and functional properties. FEBS J 2009; 276:4693-704. [PMID: 19663904 DOI: 10.1111/j.1742-4658.2009.07195.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
One of the most challenging questions in modern plant science is how plants regulate their morphological and developmental adaptation in response to changes in their biotic and abiotic environment. A comprehensive elucidation of the underlying mechanisms will help shed light on the extremely efficient strategies of plants in terms of survival and propagation. In recent years, a number of environmental stress conditions have been described as being mediated by signaling molecules of the oxylipin family. In this context, jasmonic acid, its biosynthetic precursor, 12-oxo-phytodienoic acid (OPDA), and also reactive electrophilic species such as phytoprostanes play pivotal roles. Although our understanding of jasmonic acid-dependent processes and jasmonic acid signal-transduction cascades has made considerable progress in recent years, knowledge of the regulation and mode of action of OPDA-dependent plant responses is just emerging. This minireview focuses on recent work concerned with the elucidation of OPDA-specific processes in plants. In this context, aspects such as the differential recruitment of OPDA, either by de novo biosynthesis or by release from cyclo-oxylipin-galactolipids, and the conjugation of free OPDA are discussed.
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73
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Sun J, Xu Y, Ye S, Jiang H, Chen Q, Liu F, Zhou W, Chen R, Li X, Tietz O, Wu X, Cohen JD, Palme K, Li C. Arabidopsis ASA1Is Important for Jasmonate-Mediated Regulation of Auxin Biosynthesis and Transport during Lateral Root Formation. THE PLANT CELL 2009; 21:1495-511. [PMID: 19435934 PMCID: PMC2700526 DOI: 10.1105/tpc.108.064303] [Citation(s) in RCA: 223] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
AbstractPlant roots show an impressive degree of plasticity in adapting their branching patterns to ever-changing growth conditions. An important mechanism underlying this adaptation ability is the interaction between hormonal and developmental signals. Here, we analyze the interaction of jasmonate with auxin to regulate lateral root (LR) formation through characterization of an Arabidopsis thaliana mutant, jasmonate-induced defective lateral root1 (jdl1/asa1-1). We demonstrate that, whereas exogenous jasmonate promotes LR formation in wild-type plants, it represses LR formation in jdl1/asa1-1. JDL1 encodes the auxin biosynthetic gene ANTHRANILATE SYNTHASE α1 (ASA1), which is required for jasmonate-induced auxin biosynthesis. Jasmonate elevates local auxin accumulation in the basal meristem of wild-type roots but reduces local auxin accumulation in the basal meristem of mutant roots, suggesting that, in addition to activating ASA1-dependent auxin biosynthesis, jasmonate also affects auxin transport. Indeed, jasmonate modifies the expression of auxin transport genes in an ASA1-dependent manner. We further provide evidence showing that the action mechanism of jasmonate to regulate LR formation through ASA1 differs from that of ethylene. Our results highlight the importance of ASA1 in jasmonate-induced auxin biosynthesis and reveal a role for jasmonate in the attenuation of auxin transport in the root and the fine-tuning of local auxin distribution in the root basal meristem.
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Affiliation(s)
- Jiaqiang Sun
- State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- Chinese-German Joint Group for Plant Hormone Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yingxiu Xu
- State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- Graduate School of Chinese Academy of Sciences, Beijing, 100039, China
| | - Songqing Ye
- Department of Horticultural Science, Microbial and Plant Genomics Institute, University of Minnesota, St. Paul, Minnesota 55108
| | - Hongling Jiang
- State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Qian Chen
- State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- Chinese-German Joint Group for Plant Hormone Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- Graduate School of Chinese Academy of Sciences, Beijing, 100039, China
| | - Fang Liu
- State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- Chinese-German Joint Group for Plant Hormone Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- Graduate School of Chinese Academy of Sciences, Beijing, 100039, China
| | - Wenkun Zhou
- State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- Graduate School of Chinese Academy of Sciences, Beijing, 100039, China
| | - Rong Chen
- State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- Chinese-German Joint Group for Plant Hormone Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- Graduate School of Chinese Academy of Sciences, Beijing, 100039, China
| | - Xugang Li
- Chinese-German Joint Group for Plant Hormone Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- Institute for Biology II/Botany and Freiburg Institute of Advanced Sciences, Faculty of Biology, University of Freiburg, D-79104 Freiburg, Germany
| | - Olaf Tietz
- Chinese-German Joint Group for Plant Hormone Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- Institute for Biology II/Botany and Freiburg Institute of Advanced Sciences, Faculty of Biology, University of Freiburg, D-79104 Freiburg, Germany
| | - Xiaoyan Wu
- State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Jerry D. Cohen
- Department of Horticultural Science, Microbial and Plant Genomics Institute, University of Minnesota, St. Paul, Minnesota 55108
| | - Klaus Palme
- Chinese-German Joint Group for Plant Hormone Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- Institute for Biology II/Botany and Freiburg Institute of Advanced Sciences, Faculty of Biology, University of Freiburg, D-79104 Freiburg, Germany
| | - Chuanyou Li
- State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- Chinese-German Joint Group for Plant Hormone Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
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Abstract
Plant growth and development is regulated by a structurally unrelated collection of small molecules called plant hormones. During the last 15 years the number of known plant hormones has grown from five to at least ten. Furthermore, many of the proteins involved in plant hormone signalling pathways have been identified, including receptors for many of the major hormones. Strikingly, the ubiquitin-proteasome pathway plays a central part in most hormone-signalling pathways. In addition, recent studies confirm that hormone signalling is integrated at several levels during plant growth and development.
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75
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Mosblech A, Feussner I, Heilmann I. Oxylipins: structurally diverse metabolites from fatty acid oxidation. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2009; 47:511-7. [PMID: 19167233 DOI: 10.1016/j.plaphy.2008.12.011] [Citation(s) in RCA: 262] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2008] [Revised: 11/13/2008] [Accepted: 12/08/2008] [Indexed: 05/19/2023]
Abstract
Oxylipins are lipophilic signaling molecules derived from the oxidation of polyunsaturated fatty acids. Initial fatty acid oxidation occurs mainly by the enzymatic or chemical formation of fatty acid hydroperoxides. An array of alternative reactions further converting fatty acid hydroperoxides gives rise to a multitude of oxylipin classes, many with reported signaling functions in plants. Oxylipins include the phytohormone, jasmonic acid, and a number of other molecules including hydroxy-, oxo- or keto-fatty acids or volatile aldehydes that may perform various biological roles as second messengers, messengers in inter-organismic signaling, or even as bactericidal agents. The structural diversity of oxylipins is further increased by esterification of the compounds in plastidial glycolipids, for instance the Arabidopsides, or by conjugation of oxylipins to amino acids or other metabolites. The enzymes involved in oxylipin metabolism are diverse and comprise a multitude of examples with interesting and unusual catalytic properties. In addition, the interplay of different subcellular compartments during oxylipin biosynthesis suggests complex mechanisms of regulation that are not well understood. This review aims at giving an overview of plant oxylipins and the multitude of enzymes responsible for their biosynthesis.
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Affiliation(s)
- Alina Mosblech
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, Göttingen, Germany
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76
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Chung HS, Howe GA. A critical role for the TIFY motif in repression of jasmonate signaling by a stabilized splice variant of the JASMONATE ZIM-domain protein JAZ10 in Arabidopsis. THE PLANT CELL 2009; 21:131-45. [PMID: 19151223 PMCID: PMC2648087 DOI: 10.1105/tpc.108.064097] [Citation(s) in RCA: 293] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2008] [Revised: 12/22/2008] [Accepted: 01/02/2009] [Indexed: 05/17/2023]
Abstract
JASMONATE ZIM-domain (JAZ) proteins act as repressors of jasmonate (JA) signaling. Perception of bioactive JAs by the F-box protein CORONATINE INSENSITIVE1 (COI1) causes degradation of JAZs via the ubiquitin-proteasome pathway, which in turn activates the expression of genes involved in plant growth, development, and defense. JAZ proteins contain two highly conserved sequence regions: the Jas domain that interacts with COI1 to destabilize the repressor and the ZIM domain of unknown function. Here, we show that the conserved TIFY motif (TIFF/YXG) within the ZIM domain mediates homo- and heteromeric interactions between most Arabidopsis thaliana JAZs. We have also identified an alternatively spliced form (JAZ10.4) of JAZ10 that lacks the Jas domain and, as a consequence, is highly resistant to JA-induced degradation. Strong JA-insensitive phenotypes conferred by overexpression of JAZ10.4 were suppressed by mutations in the TIFY motif that block JAZ10.4-JAZ interactions. We conclude that JAZ10.4 functions to attenuate signal output in the presence of JA and further suggest that the dominant-negative action of this splice variant involves protein-protein interaction through the ZIM/TIFY domain. The ability of JAZ10.4 to interact with MYC2 is consistent with a model in which a JAZ10.4-containing protein complex directly represses the activity of transcription factors that promote expression of JA response genes.
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Affiliation(s)
- Hoo Sun Chung
- Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
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77
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Browse J. Jasmonate passes muster: a receptor and targets for the defense hormone. ANNUAL REVIEW OF PLANT BIOLOGY 2009; 60:183-205. [PMID: 19025383 DOI: 10.1146/annurev.arplant.043008.092007] [Citation(s) in RCA: 593] [Impact Index Per Article: 39.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The oxylipin jasmonate (JA) regulates many aspects of growth, development, and environmental responses in plants, particularly defense responses against herbivores and necrotrophic pathogens. Mutants of Arabidopsis helped researchers define the biochemical pathway for synthesis of jasmonoyl-isoleucine (JA-Ile), the active form of JA hormone, and demonstrated that JA is required for plant survival of insect and pathogen attacks and for plant fertility. Transcriptional profiling led to the discovery of the JASMONATE ZIM-DOMAIN (JAZ) proteins, which are repressors of JA signaling. JA-Ile relieves repression by promoting binding of the JAZ proteins to the F-box protein CORONATINE INSENSITIVE1 (COI1) and their subsequent degradation by the ubiquitination/26S-proteasome pathway. Although we now have a much better understanding of the molecular mechanism of JA action, many questions remain. Experimental answers to these questions will expand our knowledge of oxylipin signaling in plants and animals and will also provide new tools for efforts to improve crop protection and reproductive performance.
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Affiliation(s)
- John Browse
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340, USA.
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78
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Dueckershoff K, Mueller S, Mueller MJ, Reinders J. Impact of cyclopentenone-oxylipins on the proteome of Arabidopsis thaliana. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2008; 1784:1975-85. [DOI: 10.1016/j.bbapap.2008.09.003] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2008] [Revised: 07/28/2008] [Accepted: 09/08/2008] [Indexed: 01/02/2023]
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79
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Nandakumar M, Tan MW. Gamma-linolenic and stearidonic acids are required for basal immunity in Caenorhabditis elegans through their effects on p38 MAP kinase activity. PLoS Genet 2008; 4:e1000273. [PMID: 19023415 PMCID: PMC2581601 DOI: 10.1371/journal.pgen.1000273] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2008] [Accepted: 10/20/2008] [Indexed: 12/31/2022] Open
Abstract
Polyunsaturated fatty acids (PUFAs) form a class of essential micronutrients that play a vital role in development, cardiovascular health, and immunity. The influence of lipids on the immune response is both complex and diverse, with multiple studies pointing to the beneficial effects of long-chain fatty acids in immunity. However, the mechanisms through which PUFAs modulate innate immunity and the effects of PUFA deficiencies on innate immune functions remain to be clarified. Using the Caenorhabditis elegans-Pseudomonas aeruginosa host-pathogen system, we present genetic evidence that a Delta6-desaturase FAT-3, through its two 18-carbon products--gamma-linolenic acid (GLA, 18:3n6) and stearidonic acid (SDA, 18:4n3), but not the 20-carbon PUFAs arachidonic acid (AA, 20:4n6) and eicosapentaenoic acid (EPA, 20:5n3)--is required for basal innate immunity in vivo. Deficiencies in GLA and SDA result in increased susceptibility to bacterial infection, which is associated with reduced basal expression of a number of immune-specific genes--including spp-1, lys-7, and lys-2--that encode antimicrobial peptides. GLA and SDA are required to maintain basal activity of the p38 MAP kinase pathway, which plays important roles in protecting metazoan animals from infections and oxidative stress. Transcriptional and functional analyses of fat-3-regulated genes revealed that fat-3 is required in the intestine to regulate the expression of infection- and stress-response genes, and that distinct sets of genes are specifically required for immune function and oxidative stress response. Our study thus uncovers a mechanism by which these 18-carbon PUFAs affect basal innate immune function and, consequently, the ability of an organism to defend itself against bacterial infections. The conservation of p38 MAP kinase signaling in both stress and immune responses further encourages exploring the function of GLA and SDA in humans.
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Affiliation(s)
- Madhumitha Nandakumar
- Department of Genetics, Stanford University School of Medicine, Stanford, California, United States of America
- Department Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, United States of America
- Program in Immunology, Stanford University School of Medicine, Stanford, California, United States of America
| | - Man-Wah Tan
- Department of Genetics, Stanford University School of Medicine, Stanford, California, United States of America
- Department Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, United States of America
- Program in Immunology, Stanford University School of Medicine, Stanford, California, United States of America
- * E-mail:
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80
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Bannenberg G, Martínez M, Hamberg M, Castresana C. Diversity of the enzymatic activity in the lipoxygenase gene family of Arabidopsis thaliana. Lipids 2008; 44:85-95. [PMID: 18949503 DOI: 10.1007/s11745-008-3245-7] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2008] [Accepted: 09/18/2008] [Indexed: 11/24/2022]
Abstract
Lipoxygenases (LOX) catalyze the oxygenation of polyunsaturated fatty acids, the first step in the biosynthesis of a large group of biologically active fatty acid metabolites collectively named oxylipins. In the present study we report the characterization of the enzymatic activity of the six lipoxygenases found in the genome of the model plant Arabidopsis thaliana. Recombinant expressed AtLOX-1 and AtLOX-5 had comparable oxygenase activity with either linoleic acid or linolenic acid. AtLOX-2, AtLOX-3, AtLOX-4 and AtLOX-6 displayed a selective oxygenation of linolenic acid. Analyses by high-performance liquid chromatography and gas chromatography-mass spectrometry demonstrated that AtLOX-1 and AtLOX-5 are 9S-lipoxygenases, and AtLOX-2, AtLOX-3, AtLOX-4 and AtLOX-6 are 13S-lipoxygenases. None of the enzymes had dual positional specificity. The determined activities correlated with that predicted by their phylogenetic relationship to other biochemically-characterized plant lipoxygenases.
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Affiliation(s)
- Gerard Bannenberg
- Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología, CSIC, Madrid, Spain.
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81
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Glauser G, Grata E, Rudaz S, Wolfender JL. High-resolution profiling of oxylipin-containing galactolipids in Arabidopsis extracts by ultra-performance liquid chromatography/time-of-flight mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2008; 22:3154-60. [PMID: 18798198 DOI: 10.1002/rcm.3716] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
A high-resolution ultra-performance liquid chromatography/time-of-flight mass spectrometry (UPLC/TOFMS) method using in-source collision-induced dissociation (CID) was developed for globally profiling oxylipin-containing galactolipids in Arabidopsis wounded leaves. MS and pseudo-MS/MS spectra were obtained during a single analytical run by switching a lens of the TOFMS transfer optics from low to high voltage. Numerous known galactolipids were observed, and four novel mono- or di-galactosyl monoacylglycerides (MGMGs or DGMGs) containing oxophytodienoic acid (OPDA) or dinor-oxophytodienoic acid (dn-OPDA), esterified respectively at the sn1 and the sn2 positions, were identified. Rapid microisolation of the galactolipids followed by alkaline and enzymatic hydrolyses enabled the release of the esterified oxylipins, which allowed for the unambiguous characterization of the oxylipin-containing monoacylglycerides. Their strong induction in response to wounding indicates that these compounds are probably lysogalactolipids formed from galactosyldiglycerides in the injured tissues.
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Affiliation(s)
- Gaetan Glauser
- Laboratory of Pharmacognosy and Phytochemistry, School of Pharmaceutical Sciences, EPGL, University of Geneva, University of Lausanne, 30 quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
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82
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Katsir L, Chung HS, Koo AJ, Howe GA. Jasmonate signaling: a conserved mechanism of hormone sensing. CURRENT OPINION IN PLANT BIOLOGY 2008; 11:428-35. [PMID: 18583180 PMCID: PMC2560989 DOI: 10.1016/j.pbi.2008.05.004] [Citation(s) in RCA: 227] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2008] [Revised: 05/12/2008] [Accepted: 05/16/2008] [Indexed: 05/20/2023]
Abstract
The lipid-derived hormone jasmonate (JA) regulates diverse aspects of plant immunity and development. Among the central components of the JA signaling cascade are the E3 ubiquitin ligase SCFCOI1 and Jasmonate ZIM-domain (JAZ) proteins that repress transcription of JA-responsive genes. Recent studies provide evidence that amino acid-conjugated forms of JA initiate signal transduction upon formation of a coronatine-insensitive1 (COI1)-JA-JAZ ternary complex in which JAZs are ubiquitinated and subsequently degraded. Coronatine, a virulence factor produced by the plant pathogen Pseudomonas syringae, is a potent agonist of this hormone receptor system. Coronatine-induced targeting of JAZs to COI1 obstructs host immune responses to P. syrinage, providing a striking example of how pathogens exploit hormone signaling pathways in the host to promote disease. These findings, together with homology between COI1 and the auxin receptor, TIR1, extend the paradigm of F-box proteins as intracellular sensors of small molecules, and suggest a common evolutionary origin of the auxin and JA response pathways.
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83
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Glauser G, Grata E, Dubugnon L, Rudaz S, Farmer EE, Wolfender JL. Spatial and temporal dynamics of jasmonate synthesis and accumulation in Arabidopsis in response to wounding. J Biol Chem 2008; 283:16400-7. [PMID: 18400744 DOI: 10.1074/jbc.m801760200] [Citation(s) in RCA: 220] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
A new metabolite profiling approach combined with an ultrarapid sample preparation procedure was used to study the temporal and spatial dynamics of the wound-induced accumulation of jasmonic acid (JA) and its oxygenated derivatives in Arabidopsis thaliana. In addition to well known jasmonates, including hydroxyjasmonates (HOJAs), jasmonoyl-isoleucine (JA-Ile), and its 12-hydroxy derivative (12-HOJA-Ile), a new wound-induced dicarboxyjasmonate, 12-carboxyjasmonoyl-l-isoleucine (12-HOOCJA-Ile) was discovered. HOJAs and 12-HOOCJA-Ile were enriched in the midveins of wounded leaves, strongly differentiating them from the other jasmonate metabolites studied. The polarity of these oxylipins at physiological pH correlated with their appearance in midveins. When the time points of accumulation of different jasmonates were determined, JA levels were found to increase within 2-5 min of wounding. Remarkably, these changes occurred throughout the plant and were not restricted to wounded leaves. The speed of the stimulus leading to JA accumulation in leaves distal to a wound is at least 3 cm/min. The data give new insights into the spatial and temporal accumulation of jasmonates and have implications in the understanding of long-distance wound signaling in plants.
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Affiliation(s)
- Gaetan Glauser
- Laboratory of Pharmacognosy and Phytochemistry, School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, 30, Quai Ernest-Ansermet, CH-1211 Geneva 4
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84
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Przybyla D, Göbel C, Imboden A, Hamberg M, Feussner I, Apel K. Enzymatic, but not non-enzymatic, 1O2-mediated peroxidation of polyunsaturated fatty acids forms part of the EXECUTER1-dependent stress response program in the flu mutant of Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2008; 54:236-48. [PMID: 18182022 DOI: 10.1111/j.1365-313x.2008.03409.x] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The conditional flu mutant of Arabidopsis accumulates excess amounts of protochlorophyllide within plastid membranes in the dark and generates singlet oxygen upon light exposure. By varying the length of the dark period, the level of the photosensitizer protochlorophyllide may be modulated, and conditions have been established that either endorse the cytotoxicity of (1)O(2) or reveal its signaling role. Two criteria have been used to distinguish between these two modes of activity of (1)O(2): the impact of the EXECUTER1 mutation and the prevalence of either non-enzymatic or enzymatic lipid peroxidation. During illumination of etiolated flu seedlings, toxic effects of (1)O(2) prevail and non-enzymatic lipid peroxidation proceeds rapidly. In contrast, in light-grown flu plants that were subjected to an 8 h dark/light shift, lipid peroxidation occurred almost exclusively enzymatically. The resulting oxidation product, 13-hydroperoxy octadecatrienoic acid (13-HPOT), serves as a substrate for synthesis of 12-oxo phytodienoic acid (OPDA) and jasmonic acid (JA), both of which are known to control various metabolic and developmental processes in plants. Inactivation of the EXECUTER1 protein abrogates not only (1)O(2)-mediated cell death and growth inhibition of flu plants, but also enzymatic lipid peroxidation. However, inactivation of jasmonate biosynthesis in the aos/flu double mutant does not affect (1)O(2)-mediated growth inhibition and cell death. Hence, JA and OPDA do not act as second messengers during (1)O(2) signaling, but form an integral part of a stress-related signaling cascade activated by (1)O(2) that encompasses several signaling pathways known to be activated by abiotic and biotic stressors.
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Affiliation(s)
- Dominika Przybyla
- Swiss Federal Institute of Technology (ETH), Institute of Plant Sciences, Universitätsstrasse 2, CH-8092 Zürich, Switzerland
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85
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Kazan K, Manners JM. Jasmonate signaling: toward an integrated view. PLANT PHYSIOLOGY 2008; 146:1459-68. [PMID: 18390489 PMCID: PMC2287326 DOI: 10.1104/pp.107.115717] [Citation(s) in RCA: 257] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2007] [Accepted: 02/04/2008] [Indexed: 05/18/2023]
Affiliation(s)
- Kemal Kazan
- Commonwealth Scientific and Industrial Research Organization Plant Industry, Queensland Bioscience Precinct, St. Lucia, Queensland 4067, Australia.
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86
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Opitz S, Kunert G, Gershenzon J. Increased terpenoid accumulation in cotton (Gossypium hirsutum) foliage is a general wound response. J Chem Ecol 2008; 34:508-22. [PMID: 18386096 PMCID: PMC2292484 DOI: 10.1007/s10886-008-9453-z] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Revised: 02/08/2008] [Accepted: 02/19/2008] [Indexed: 11/23/2022]
Abstract
The subepidermal pigment glands of cotton accumulate a variety of terpenoid products, including monoterpenes, sesquiterpenes, and terpenoid aldehydes that can act as feeding deterrents against a number of insect herbivore species. We compared the effect of herbivory by Spodoptera littoralis caterpillars, mechanical damage by a fabric pattern wheel, and the application of jasmonic acid on levels of the major representatives of the three structural classes of terpenoids in the leaf foliage of 4-week-old Gossypium hirsutum plants. Terpenoid levels increased successively from control to mechanical damage, herbivory, and jasmonic acid treatments, with E-beta-ocimene and heliocide H1 and H4 showing the highest increases, up to 15-fold. Herbivory or mechanical damage to older leaves led to terpenoid increases in younger leaves. Leaf-by-leaf analysis of terpenes and gland density revealed that higher levels of terpenoids were achieved by two mechanisms: (1) increased filling of existing glands with terpenoids and (2) the production of additional glands, which were found to be dependent on damage intensity. As the relative response of individual terpenoids did not differ substantially among herbivore, mechanical damage, and jasmonic acid treatments, the induction of terpenoids in cotton foliage appears to represent a non-specific wound response mediated by jasmonic acid.
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Affiliation(s)
- Stefan Opitz
- Department of Biochemistry, Max Planck Institute for Chemical Ecology, Hans-Knöll-Strasse 8, 07745 Jena, Germany.
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87
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Balaji V, Mayrose M, Sherf O, Jacob-Hirsch J, Eichenlaub R, Iraki N, Manulis-Sasson S, Rechavi G, Barash I, Sessa G. Tomato transcriptional changes in response to Clavibacter michiganensis subsp. michiganensis reveal a role for ethylene in disease development. PLANT PHYSIOLOGY 2008; 146:1797-809. [PMID: 18245454 PMCID: PMC2287351 DOI: 10.1104/pp.107.115188] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Clavibacter michiganensis subsp. michiganensis (Cmm) is a gram-positive actinomycete, causing bacterial wilt and canker disease in tomato (Solanum lycopersicum). Host responses to gram-positive bacteria and molecular mechanisms associated with the development of disease symptoms caused by Cmm in tomato are largely unexplored. To investigate plant responses activated during this compatible interaction, we used microarray analysis to monitor changes in host gene expression during disease development. This analysis was performed at 4 d postinoculation, when bacteria were actively multiplying and no wilt symptoms were yet visible; and at 8 d postinoculation, when bacterial growth approached saturation and typical wilt symptoms were observed. Of the 9,254 tomato genes represented on the array, 122 were differentially expressed in Cmm-infected plants, compared with mock-inoculated plants. Functional classification of Cmm-responsive genes revealed that Cmm activated typical basal defense responses in the host, including induction of defense-related genes, production and scavenging of free oxygen radicals, enhanced protein turnover, and hormone synthesis. Cmm infection also induced a subset of host genes involved in ethylene biosynthesis and response. After inoculation with Cmm, Never ripe (Nr) mutant plants, impaired in ethylene perception, and transgenic plants with reduced ethylene synthesis showed significant delay in the appearance of wilt symptoms, compared with wild-type plants. The retarded wilting in Nr plants was a specific effect of ethylene insensitivity, and was not due to altered expression of defense-related genes, reduced bacterial populations, or decreased ethylene synthesis. Taken together, our results indicate that host-derived ethylene plays an important role in regulation of the tomato susceptible response to Cmm.
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Affiliation(s)
- Vasudevan Balaji
- Department of Plant Sciences, Tel Aviv University, Tel Aviv 69978, Israel
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88
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Chung HS, Koo AJK, Gao X, Jayanty S, Thines B, Jones AD, Howe GA. Regulation and function of Arabidopsis JASMONATE ZIM-domain genes in response to wounding and herbivory. PLANT PHYSIOLOGY 2008; 146:952-64. [PMID: 18223147 PMCID: PMC2259048 DOI: 10.1104/pp.107.115691] [Citation(s) in RCA: 319] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2007] [Accepted: 01/21/2008] [Indexed: 05/18/2023]
Abstract
Jasmonate (JA) and its amino acid conjugate, jasmonoyl-isoleucine (JA-Ile), play important roles in regulating plant defense responses to insect herbivores. Recent studies indicate that JA-Ile promotes the degradation of JASMONATE ZIM-domain (JAZ) transcriptional repressors through the activity of the E(3) ubiquitin-ligase SCF(COI1). Here, we investigated the regulation and function of JAZ genes during the interaction of Arabidopsis (Arabidopsis thaliana) with the generalist herbivore Spodoptera exigua. Most members of the JAZ gene family were highly expressed in response to S. exigua feeding and mechanical wounding. JAZ transcript levels increased within 5 min of mechanical tissue damage, coincident with a large (approximately 25-fold) rise in JA and JA-Ile levels. Wound-induced expression of JAZ and other CORONATINE-INSENSITIVE1 (COI1)-dependent genes was not impaired in the jar1-1 mutant that is partially deficient in the conversion of JA to JA-Ile. Experiments performed with the protein synthesis inhibitor cycloheximide provided evidence that JAZs, MYC2, and genes encoding several JA biosynthetic enzymes are primary response genes whose expression is derepressed upon COI1-dependent turnover of a labile repressor protein(s). We also show that overexpression of a modified form of JAZ1 (JAZ1Delta3A) that is stable in the presence of JA compromises host resistance to feeding by S. exigua larvae. These findings establish a role for JAZ proteins in the regulation of plant anti-insect defense, and support the hypothesis that JA-Ile and perhaps other JA derivatives activate COI1-dependent wound responses in Arabidopsis. Our results also indicate that the timing of JA-induced transcription in response to wounding is more rapid than previously realized.
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Affiliation(s)
- Hoo Sun Chung
- Department of Energy Plant Research Laboratory , Michigan State University, East Lansing, MI 48824, USA
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89
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Browse J, Howe GA. New weapons and a rapid response against insect attack. PLANT PHYSIOLOGY 2008; 146:832-8. [PMID: 18316637 PMCID: PMC2259070 DOI: 10.1104/pp.107.115683] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2007] [Accepted: 01/08/2008] [Indexed: 05/18/2023]
Affiliation(s)
- John Browse
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340, USA
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90
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Staswick PE. JAZing up jasmonate signaling. TRENDS IN PLANT SCIENCE 2008; 13:66-71. [PMID: 18261950 DOI: 10.1016/j.tplants.2007.11.011] [Citation(s) in RCA: 182] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2007] [Revised: 11/15/2007] [Accepted: 11/19/2007] [Indexed: 05/21/2023]
Abstract
Recent discoveries show that jasmonate ZIM-domain (JAZ) transcriptional repressors are key regulators of jasmonate hormonal response. Jasmonate promotes interaction between JAZ proteins and the SCF(COI1) ubiquitin ligase, leading to JAZ degradation via the 26S proteasome in Arabidopsis thaliana. Elimination of JAZ repressors then frees the MYC2 transcription factor to stimulate jasmonate-dependent gene expression. Although jasmonic acid and methyl jasmonate were thought to be key regulators of jasmonate responses, they were ineffective in promoting SCF(COI1)-JAZ interaction and it is the isoleucine conjugate of jasmonic acid that acts in this signal transduction pathway. The discovery of JAZ transcriptional regulators greatly advances our understanding of how jasmonate signaling regulates plant growth and response to the environment.
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Affiliation(s)
- Paul E Staswick
- Department of Agronomy and Horticulture, University of Nebraska, Lincoln, NE 68585, USA
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91
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Molecular cloning and expression profiling of the first specific jasmonate biosynthetic pathway gene allene oxide synthase from Lonicera japonica. Mol Biol Rep 2008; 36:487-93. [PMID: 18167030 DOI: 10.1007/s11033-007-9205-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2007] [Accepted: 12/19/2007] [Indexed: 10/22/2022]
Abstract
In jasmonate biosynthetic pathway, allene oxide synthase (AOS, EC 4.2.1.92), which is a cytochrome P450 (CYP74A), catalyzes the first committed step. We herein cloned a novel cDNA from Lonicera japonica Thunb., named LjAOS (GenBank accession: DQ303120), which was homologous to other AOSs. Southern blot analysis revealed that it was a multi-copy gene. Real-time quantitative PCR analysis showed that LjAOS mRNA accumulated most abundantly in alabastrums, in which the content of chlorogenic acid (CA, the major important active ingredient indicator) was previously proven to be the highest.
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92
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Stone SL, Callis J. Ubiquitin ligases mediate growth and development by promoting protein death. CURRENT OPINION IN PLANT BIOLOGY 2007; 10:624-32. [PMID: 17851112 DOI: 10.1016/j.pbi.2007.07.010] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2007] [Revised: 07/17/2007] [Accepted: 07/26/2007] [Indexed: 05/17/2023]
Abstract
The ubiquitin proteasome system (UPS) allows plants to effectively and efficiently alter their proteome so as to ensure developmental plasticity and environmental adaptation. Recent work has demonstrated that the UPS is an integral part of multiple hormone-signaling pathways, which modulate cell growth and differentiation. In response to variation in hormone levels, the UPS regulates the abundance of signaling factors, mainly hormone-responsive transcription factors, which mediate cellular responses. Recent exciting studies have shown that hormones directly or indirectly modulate substrate ubiquitination by regulating E3-substrate interaction. Other avenues of regulation include regulating E3 mRNA abundance.
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Affiliation(s)
- Sophia L Stone
- Department of Biology, Dalhousie University, 1355 Oxford St., Halifax, NS B3H 4J1, Canada
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93
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Vanderbeld B, Snedden WA. Developmental and stimulus-induced expression patterns of Arabidopsis calmodulin-like genes CML37, CML38 and CML39. PLANT MOLECULAR BIOLOGY 2007; 64:683-97. [PMID: 17579812 DOI: 10.1007/s11103-007-9189-0] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2007] [Accepted: 05/13/2007] [Indexed: 05/15/2023]
Abstract
Various aspects of plant development and stress physiology are mediated by Ca(2+) signaling. Ca(2+) sensors, such as calmodulin, detect these signals and direct downstream signaling pathways by binding and activating diverse targets. Plants possess many unique, putative Ca(2+) sensors, including a large family (50 in Arabidopsis) of calmodulin-like proteins termed CMLs. Some of these CMLs have been implicated in Ca(2+)-based stress response but most remain unstudied. We generated transgenic plants expressing CML::GUS reporter genes for members of a subfamily of CMLs (CML37, CML38 and CML39) which allowed us to investigate their expression patterns in detail. We found that CML::GUS genes displayed unique tissue, cell-type, and temporal patterns of expression throughout normal development, particularly in the flower, and in response to a variety of stimuli, including biotic and abiotic stress, hormone and chemical treatments. Our findings are supported by semiquantitative reverse-transcription PCR as well as analyses of microarray databases. Analysis of purified, recombinant CMLs demonstrated their ability to bind Ca(2+) in vitro. Collectively, our data suggest that these CMLs likely play important roles as sensors in Ca(2+)-mediated developmental and stress response pathways and provide a framework of spatial and temporal expression to direct future studies aimed at elucidating their physiological roles.
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Affiliation(s)
- Barbara Vanderbeld
- Department of Biology, Queen's University, Kingston, ON, Canada, K7L 3N6
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94
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Yan Y, Stolz S, Chételat A, Reymond P, Pagni M, Dubugnon L, Farmer EE. A downstream mediator in the growth repression limb of the jasmonate pathway. THE PLANT CELL 2007; 19:2470-83. [PMID: 17675405 PMCID: PMC2002611 DOI: 10.1105/tpc.107.050708] [Citation(s) in RCA: 514] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Wounding plant tissues initiates large-scale changes in transcription coupled to growth arrest, allowing resource diversion for defense. These processes are mediated in large part by the potent lipid regulator jasmonic acid (JA). Genes selected from a list of wound-inducible transcripts regulated by the jasmonate pathway were overexpressed in Arabidopsis thaliana, and the transgenic plants were then assayed for sensitivity to methyl jasmonate (MeJA). When grown in the presence of MeJA, the roots of plants overexpressing a gene of unknown function were longer than those of wild-type plants. When transcript levels for this gene, which we named JASMONATE-ASSOCIATED1 (JAS1), were reduced by RNA interference, the plants showed increased sensitivity to MeJA and growth was inhibited. These gain- and loss-of-function assays suggest that this gene acts as a repressor of JA-inhibited growth. An alternative transcript from the gene encoding a second protein isoform with a longer C terminus failed to repress jasmonate sensitivity. This identified a conserved C-terminal sequence in JAS1 and related genes, all of which also contain Zim motifs and many of which are jasmonate-regulated. Both forms of JAS1 were found to localize to the nucleus in transient expression assays. Physiological tests of growth responses after wounding were consistent with the fact that JAS1 is a repressor of JA-regulated growth retardation.
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Affiliation(s)
- Yuanxin Yan
- Department of Plant Molecular Biology, University of Lausane, Biophore, CH-1015 Lausane, Switzerland
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95
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Broekgaarden C, Poelman EH, Steenhuis G, Voorrips RE, Dicke M, Vosman B. Genotypic variation in genome-wide transcription profiles induced by insect feeding: Brassica oleracea--Pieris rapae interactions. BMC Genomics 2007; 8:239. [PMID: 17640338 PMCID: PMC1940009 DOI: 10.1186/1471-2164-8-239] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2007] [Accepted: 07/17/2007] [Indexed: 11/12/2022] Open
Abstract
Background Transcriptional profiling after herbivore attack reveals, at the molecular level, how plants respond to this type of biotic stress. Comparing herbivore-induced transcriptional responses of plants with different phenotypes provides insight into plant defense mechanisms. Here, we compare the global gene expression patterns induced by Pieris rapae caterpillar attack in two white cabbage (Brassica oleracea var. capitata) cultivars. The two cultivars are shown to differ in their level of direct defense against caterpillar feeding. Because Brassica full genome microarrays are not yet available, 70-mer oligonucleotide microarrays based on the Arabidopsis thaliana genome were used for this non-model plant. Results The transcriptional responses of the two cultivars differed in timing as characterized by changes in their expression pattern after 24, 48 and 72 hours of caterpillar feeding. In addition, they also differed qualitatively. Surprisingly, of all genes induced at any time point, only one third was induced in both cultivars. Analyses of transcriptional responses after jasmonate treatment revealed that the difference in timing did not hold for the response to this phytohormone. Additionally, comparisons between Pieris rapae- and jasmonate-induced transcriptional responses showed that Pieris rapae induced more jasmonate-independent than jasmonate-dependent genes. Conclusion The present study clearly shows that global transcriptional responses in two cultivars of the same plant species in response to insect feeding can differ dramatically. Several of these differences involve genes that are known to have an impact on Pieris rapae performance and probably underlie different mechanisms of direct defense, present in the cultivars.
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Affiliation(s)
- Colette Broekgaarden
- Plant Research International B.V., Wageningen University and Research Centre, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
- Laboratory of Entomology, Wageningen University, P.O. Box 8031, 6700 EH Wageningen, The Netherlands
| | - Erik H Poelman
- Laboratory of Entomology, Wageningen University, P.O. Box 8031, 6700 EH Wageningen, The Netherlands
| | - Greet Steenhuis
- Plant Research International B.V., Wageningen University and Research Centre, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Roeland E Voorrips
- Plant Research International B.V., Wageningen University and Research Centre, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Marcel Dicke
- Laboratory of Entomology, Wageningen University, P.O. Box 8031, 6700 EH Wageningen, The Netherlands
| | - Ben Vosman
- Plant Research International B.V., Wageningen University and Research Centre, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
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96
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Zhai Q, Li CB, Zheng W, Wu X, Zhao J, Zhou G, Jiang H, Sun J, Lou Y, Li C. Phytochrome chromophore deficiency leads to overproduction of jasmonic acid and elevated expression of jasmonate-responsive genes in Arabidopsis. PLANT & CELL PHYSIOLOGY 2007; 48:1061-71. [PMID: 17567636 DOI: 10.1093/pcp/pcm076] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
An Arabidopsis mutant line named hy1-101 was isolated because it shows stunted root growth on medium containing low concentrations of jasmonic acid (JA). Subsequent investigation indicated that even in the absence of JA, hy1-101 plants exhibit shorter roots and express higher levels of a group of JA-inducible defense genes. Here, we show that the hy1-101 mutant has increased production of JA and its jasmonate-related phenotype is suppressed by the coi1-1 mutation that interrupts JA signaling. Gene cloning and genetic complementation analyses revealed that the hy1-101 mutant contains a mutation in the HY1 gene, which encodes a heme oxygenase essential for phytochrome chromophore biosynthesis. These results support a hypothesis that phytochrome chromophore deficiency leads to overproduction of JA and activates COI1-dependent JA responses. Indeed, we show that, like hy1-101, independent alleles of the phytochrome chromophore-deficient mutants, including hy1-100 and hy2 (CS68), also show elevated JA levels and constant expression of JA-inducible defense genes. We further provide evidence showing that, on the other hand, JA inhibits the expression of a group of light-inducible and photosynthesis-related genes. Together, these data imply that the JA-signaled defense pathway and phytochrome chromophore-mediated light signaling might have antagonistic effects on each other.
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Affiliation(s)
- Qingzhe Zhai
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, PR China
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97
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Huffaker A, Ryan CA. Endogenous peptide defense signals in Arabidopsis differentially amplify signaling for the innate immune response. Proc Natl Acad Sci U S A 2007; 104:10732-6. [PMID: 17566109 PMCID: PMC1965581 DOI: 10.1073/pnas.0703343104] [Citation(s) in RCA: 156] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
AtPep1, a 23-aa peptide encoded by Arabidopsis PROPEP1, a member of a small, six-member gene family, activates expression of the defense gene PDF1.2 (encoding defensin) and its own precursor gene, PROPEP1, through the jasmonate/ethylene signaling pathway, mediated by a cell-surface receptor, PEPR1. Overexpression of two family members, PROPEP1 and PROPEP2, enhances resistance of Arabidopsis plants against the pathogen Pythium irregulare, and PROPEP2 and PROPEP3 are expressed at highly elevated levels in Arabidopsis in response to pathogen infections and to several pathogen-associated molecules (general elicitors). Here, we report that PDF1.2, PR-1 (pathogenesis protein), and PROPEP genes were differentially expressed in the leaves of intact plants sprayed with methyl jasmonate and methyl salicylate and in excised leaves supplied through cut petioles with peptides derived from the C terminus of each of the encoded proteins. The expression of PDF1.2 and PR-1 elicited by the peptides was blocked in mutant plants deficient in the jasmonate/ethylene and salicylate pathways, and in wild-type plants by treatment with diphenylene iodonium chloride, an inhibitor of hydrogen peroxide production. PROPEP1, PROPEP 2, and PROPEP3 genes appear to have roles in a feedback loop that amplifies defense signaling pathways initiated by pathogens.
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Affiliation(s)
- Alisa Huffaker
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340
| | - Clarence A. Ryan
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340
- *To whom correspondence should be addressed. E-mail:
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98
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Delker C, Zolman BK, Miersch O, Wasternack C. Jasmonate biosynthesis in Arabidopsis thaliana requires peroxisomal beta-oxidation enzymes--additional proof by properties of pex6 and aim1. PHYTOCHEMISTRY 2007; 68:1642-50. [PMID: 17544464 DOI: 10.1016/j.phytochem.2007.04.024] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2007] [Revised: 04/17/2007] [Accepted: 04/17/2007] [Indexed: 05/15/2023]
Abstract
Jasmonic acid (JA) is an important regulator of plant development and stress responses. Several enzymes involved in the biosynthesis of JA from alpha-linolenic acid have been characterized. The final biosynthesis steps are the beta-oxidation of 12-oxo-phytoenoic acid. We analyzed JA biosynthesis in the Arabidopsis mutants pex6, affected in peroxisome biogenesis, and aim1, disrupted in fatty acid beta-oxidation. Upon wounding, these mutants exhibit reduced JA levels compared to wild type. pex6 accumulated the precursor OPDA. Feeding experiments with deuterated OPDA substantiate this accumulation pattern, suggesting the mutants are impaired in the beta-oxidation of JA biosynthesis at different steps. Decreased expression of JA-responsive genes, such as VSP1, VSP2, AtJRG21 and LOX2, following wounding in the mutants compared to the wild type reflects the reduced JA levels of the mutants. By use of these additional mutants in combination with feeding experiments, the necessity of functional peroxisomes for JA-biosynthesis is confirmed. Furthermore an essential function of one of the two multifunctional proteins of fatty acid beta-oxidation (AIM1) for wound-induced JA formation is demonstrated for the first time. These data confirm that JA biosynthesis occurs via peroxisomal fatty acid beta-oxidation machinery.
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Affiliation(s)
- Carolin Delker
- Leibniz Institute of Plant Biochemistry, Department of Natural Product Biotechnology, Weinberg 3, D-06120 Halle/S., Germany
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Jiang J, Li J, Xu Y, Han Y, Bai Y, Zhou G, Lou Y, Xu Z, Chong K. RNAi knockdown of Oryza sativa root meander curling gene led to altered root development and coiling which were mediated by jasmonic acid signalling in rice. PLANT, CELL & ENVIRONMENT 2007; 30:690-9. [PMID: 17470145 DOI: 10.1111/j.1365-3040.2007.01663.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Jasmonic acid (JA) is a well-known defence hormone, but its biological function and mechanism in rice root development are less understood. Here, we describe a JA-induced putative receptor-like protein (OsRLK, AAL87185) functioning in root development in rice. RNA in situ hybridization revealed that the gene was expressed largely in roots, and a fusion protein showed its localization on the plasma membrane. The primary roots in RNAi transgenic rice plants meandered and curled more easily than wild-type (WT) roots under JA treatment. Thus, this gene was renamed Oryza sativa root meander curling (OsRMC). The transgenic primary roots were shorter, the number of adventitious roots increased and the number of lateral roots decreased as compared to the WT. As well, the second sheath was reduced in length. Growth of both primary roots and second sheaths was sensitive to JA treatment. No significant change of JA level appeared in the roots between the transgenic rice line and WT. Expression of RSOsPR10, involved in the JA signalling pathway, was induced in transgenic rice. Western blotting revealed OsRMC induced by JA. Our results suggest that OsRMC of the DUF26 subfamily involved in JA signal transduction mediates root development and negatively regulates root curling in rice.
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Affiliation(s)
- Jiafu Jiang
- Research Center for Molecular Developmental Biology, Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, and Graduate School of the Chinese Academy of Sciences, Beijing, China
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Schilmiller AL, Koo AJK, Howe GA. Functional diversification of acyl-coenzyme A oxidases in jasmonic acid biosynthesis and action. PLANT PHYSIOLOGY 2007; 143:812-24. [PMID: 17172287 PMCID: PMC1803733 DOI: 10.1104/pp.106.092916] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The biosynthesis of jasmonic acid (JA) in plant peroxisomes requires the action of acyl-coenzyme A oxidase (ACX). Among the five expressed members (ACX1-5) of the ACX gene family in Arabidopsis (Arabidopsis thaliana), only ACX1 is known to serve a role in JA production. Here, we used transgenic promoter-reporter lines to show that ACX1 is highly expressed in mature and germinating pollen, stem epidermal cells, and other tissues in which jasmonate-signaled processes occur. Wound-induced JA accumulation was reduced in a mutant that is defective in ACX1 and was abolished in a mutant that is impaired in both ACX1 and its closely related paralog, ACX5. The severe JA deficiency in acx1/5 double mutants was accompanied by decreased resistance to the leaf-eating insect Trichoplusia ni. The double mutant also showed reduced pollen viability and fecundity. Treatment of acx1/5 plants with JA restored both protection against T. ni larvae and normal seed set. Unexpectedly, acx1/5 plants accumulated JA in response to infection by the necrotrophic fungal pathogen Alternaria brassicicola. In contrast to mutants that are impaired in jasmonate perception or early steps of the JA biosynthetic pathway, acx1/5 plants maintained resistance to A. brassicicola infection. These results indicate that ACX1/5-mediated JA synthesis is essential for resistance to chewing insects and male reproductive function and further suggest that other ACX isozymes contribute to JA production in response to A. brassicicola challenge. Thus, different types of biotic stress may induce JA synthesis via distinct enzymatic routes.
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Affiliation(s)
- Anthony L Schilmiller
- Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
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