201
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Schlink K. Down-regulation of defense genes and resource allocation into infected roots as factors for compatibility between Fagus sylvatica and Phytophthora citricola. Funct Integr Genomics 2009; 10:253-64. [PMID: 19813036 DOI: 10.1007/s10142-009-0143-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2009] [Revised: 08/29/2009] [Accepted: 09/13/2009] [Indexed: 12/30/2022]
Abstract
Phytophthora citricola is a wide spread and highly aggressive pathogen of Fagus sylvatica. The hemibiotrophic oomycete infects the roots and establishes a compatible interaction with F. sylvatica. To investigate the transcriptional changes associated with P. citricola infection, 68 custom oligo-microarray measurements were conducted. Hierarchical as well as non-hierarchical clustering was carried out to analyze the expression profiles. Experimental setup includes a time scale covering the biotrophic and necrotrophic stages of interaction as well as comparative analyses of the local and systemic responses. The local reaction of F. sylvatica is characterized by a striking lack of defense gene induction leading to the conclusion that P. citricola escapes the main recognition systems and/or suppresses the host's response. The analysis of the systemic reaction revealed a massive shift in gene expression patterns during the biotrophic phase that is interpreted as evidence of resource allocation into the roots to support the increased sink caused by pathogen growth. Defense genes known to be responsive to salicylic acid (effective against biotrophs), jasmonic acid, and ethylene (effective against necrotrophs and herbivores) are represented on the arrays. All significant changes in gene expression measured for salicylic acid responsive genes were down-regulations in roots and leaves while some jasmonic acid responsive genes showed a very late up-regulation only in leaves, probably caused by the desiccation shortly before plant death. Together, these expression changes could explain the success of the pathogen.
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Affiliation(s)
- Katja Schlink
- Forest Genetics, Center of Life and Food Sciences Weihenstephan, Technische Universität München, Hans-Carl-von-Carlowitz-Platz 2, 85354, Freising, Germany.
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202
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Fonseca S, Chico JM, Solano R. The jasmonate pathway: the ligand, the receptor and the core signalling module. CURRENT OPINION IN PLANT BIOLOGY 2009; 12:539-47. [PMID: 19716757 DOI: 10.1016/j.pbi.2009.07.013] [Citation(s) in RCA: 204] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Revised: 06/16/2009] [Accepted: 07/28/2009] [Indexed: 05/20/2023]
Abstract
Jasmonates regulate specific developmental processes and plant adaptation to environment by controlling responses to external biotic or abiotic stimuli. The core events of jasmonate signalling are now defined. After hormone perception by SCF(COI1), JAZ (JAsmonate ZIM domain) repressors are targeted for proteasome degradation, releasing MYC2 and de-repressing transcriptional activation. JAZs are homomeric and heteromeric proteins and have been instrumental in recent advances in the field, such as the identification of COI1 as a critical component of the jasmonate receptor and the discovery of the bioactive jasmonate in Arabidopsis, (+)-7-iso-JA-Ile. Small changes in jasmonate structure result in hormone inactivation and might be the key to switching-off signalling for specific responses to stimulus and for long-distance signalling events.
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Affiliation(s)
- Sandra Fonseca
- Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología-CSIC, Campus Universidad Autónoma, 28049 Madrid, Spain
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203
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Kaur N, Reumann S, Hu J. Peroxisome biogenesis and function. THE ARABIDOPSIS BOOK 2009; 7:e0123. [PMID: 22303249 PMCID: PMC3243405 DOI: 10.1199/tab.0123] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Peroxisomes are small and single membrane-delimited organelles that execute numerous metabolic reactions and have pivotal roles in plant growth and development. In recent years, forward and reverse genetic studies along with biochemical and cell biological analyses in Arabidopsis have enabled researchers to identify many peroxisome proteins and elucidate their functions. This review focuses on the advances in our understanding of peroxisome biogenesis and metabolism, and further explores the contribution of large-scale analysis, such as in sillco predictions and proteomics, in augmenting our knowledge of peroxisome function In Arabidopsis.
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Affiliation(s)
| | - Sigrun Reumann
- Centre for Organelle Research, Faculty of Science and Technology, University of Stavanger, N-4036 Stavanger, Norway
| | - Jianping Hu
- MSU-DOE Plant Research Laboratory and
- Plant Biology Department, Michigan State University, East Lansing, MI 48824
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204
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Chung HS, Niu Y, Browse J, Howe GA. Top hits in contemporary JAZ: an update on jasmonate signaling. PHYTOCHEMISTRY 2009; 70:1547-59. [PMID: 19800644 PMCID: PMC3271379 DOI: 10.1016/j.phytochem.2009.08.022] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Revised: 08/06/2009] [Accepted: 08/24/2009] [Indexed: 05/19/2023]
Abstract
The phytohormone jasmonate (JA) regulates a wide range of growth, developmental, and defense-related processes during the plant life cycle. Identification of the JAZ family of proteins that repress JA responses has facilitated rapid progress in understanding how this lipid-derived hormone controls gene expression. Recent analysis of JAZ proteins has provided insight into the nature of the JA receptor, the chemical specificity of signal perception, and cross-talk between JA and other hormone response pathways. Functional diversification of JAZ proteins by alternative splicing, together with the ability of JAZ proteins to homo- and heterodimerize, provide mechanisms to enhance combinatorial diversity and versatility in gene regulation by JA.
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Affiliation(s)
- Hoo Sun Chung
- DOE Plant Research Laboratory, Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824-1312
| | - Yajie Niu
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340
| | - John Browse
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340
| | - Gregg A. Howe
- DOE Plant Research Laboratory, Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824-1312
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205
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Koo AJ, Howe GA. The wound hormone jasmonate. PHYTOCHEMISTRY 2009; 70:1571-80. [PMID: 19695649 PMCID: PMC2784233 DOI: 10.1016/j.phytochem.2009.07.018] [Citation(s) in RCA: 235] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Revised: 07/13/2009] [Accepted: 07/14/2009] [Indexed: 05/17/2023]
Abstract
Plant tissues are highly vulnerable to injury by herbivores, pathogens, mechanical stress, and other environmental insults. Optimal plant fitness in the face of these threats relies on complex signal transduction networks that link damage-associated signals to appropriate changes in metabolism, growth, and development. Many of these wound-induced adaptive responses are triggered by de novo synthesis of the plant hormone jasmonate (JA). Recent studies provide evidence that JA mediates systemic wound responses through distinct cell autonomous and non-autonomous pathways. In both pathways, bioactive JAs are recognized by an F-box protein-based receptor system that couples hormone binding to ubiquitin-dependent degradation of transcriptional repressor proteins. These results provide a framework for understanding how plants recognize and respond to tissue injury.
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Affiliation(s)
- Abraham J.K. Koo
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824
| | - Gregg A. Howe
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
- Corresponding author: Tel.: 1-517-355-5159; Fax: 1-517-353-9168. E-mail address:
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206
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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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207
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Chini A, Boter M, Solano R. Plant oxylipins: COI1/JAZs/MYC2 as the core jasmonic acid-signalling module. FEBS J 2009; 276:4682-92. [PMID: 19663905 DOI: 10.1111/j.1742-4658.2009.07194.x] [Citation(s) in RCA: 140] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Jasmonic acid (JA) and its derivates, collectively known as jasmonates (JAs), are essential signalling molecules that coordinate the plant response to biotic and abiotic challenges, in addition to several developmental processes. The COI1 F-box and additional SCF modulators have long been known to have a crucial role in the JA-signalling pathway. Downstream JA-dependent transcriptional re-programming is regulated by a cascade of transcription factors and MYC2 plays a major role. Recently, JAZ family proteins have been identified as COI1 targets and repressors of MYC2, defining the 'missing link' in JA signalling. JA-Ile has been proposed to be the active form of the hormone, and COI1 is an essential component of the receptor complex. These recent discoveries have defined the core JA-signalling pathway as the module COI1/JAZs/MYC2.
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Affiliation(s)
- Andrea Chini
- Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología-CSIC, Madrid, Spain
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208
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de Torres Zabala M, Bennett MH, Truman WH, Grant MR. Antagonism between salicylic and abscisic acid reflects early host-pathogen conflict and moulds plant defence responses. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2009; 59:375-86. [PMID: 19392690 DOI: 10.1111/j.1365-313x.2009.03875.x] [Citation(s) in RCA: 189] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The importance of phytohormone balance is increasingly recognized as central to the outcome of plant-pathogen interactions. Recently it has been demonstrated that abscisic acid signalling pathways are utilized by the bacterial phytopathogen Pseudomonas syringae to promote pathogenesis. In this study, we examined the dynamics, inter-relationship and impact of three key acidic phytohormones, salicylic acid, abscisic acid and jasmonic acid, and the bacterial virulence factor, coronatine, during progression of P. syringae infection of Arabidopsis thaliana. We show that levels of SA and ABA, but not JA, appear to play important early roles in determining the outcome of the infection process. SA is required in order to mount a full innate immune responses, while bacterial effectors act rapidly to activate ABA biosynthesis. ABA suppresses inducible innate immune responses by down-regulating SA biosynthesis and SA-mediated defences. Mutant analyses indicated that endogenous ABA levels represent an important reservoir that is necessary for effector suppression of plant-inducible innate defence responses and SA synthesis prior to subsequent pathogen-induced increases in ABA. Enhanced susceptibility due to loss of SA-mediated basal resistance is epistatically dominant over acquired resistance due to ABA deficiency, although ABA also contributes to symptom development. We conclude that pathogen-modulated ABA signalling rapidly antagonizes SA-mediated defences. We predict that hormonal perturbations, either induced or as a result of environmental stress, have a marked impact on pathological outcomes, and we provide a mechanistic basis for understanding priming events in plant defence.
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209
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Mach J. The jasmonate receptor: protein modeling and photoaffinity labeling reveal that the CORONATINE INSENSITIVE1 protein binds jasmonoyl-isoleucine and coronatine. THE PLANT CELL 2009; 21:2192. [PMID: 19717614 PMCID: PMC2751951 DOI: 10.1105/tpc.109.210811] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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210
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Hughes RK, De Domenico S, Santino A. Plant cytochrome CYP74 family: biochemical features, endocellular localisation, activation mechanism in plant defence and improvements for industrial applications. Chembiochem 2009; 10:1122-33. [PMID: 19322850 DOI: 10.1002/cbic.200800633] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Not just another P450: Shown here is a model of the overall structure of CYP74C3 with the putative membrane-binding region that is required for enzyme activation. Members of the CYP74 family of cytochrome P450 enzymes are specialised in the metabolism of hydroperoxides and play an important role in oxylipin metabolism, which is one of the main defence mechanisms employed by plants. In order to respond to their rapidly changing environments, plants have evolved complex signalling pathways, which enable tight control over stress responses. Recent work has shed new light on one of these pathways that involves the different classes of plant oxylipins that are produced through the CYP74 pathway. These phytochemicals play an important role in plant defence, and can act as direct antimicrobials or as signalling molecules that inducing the expression of defence genes. The fine-tuning regulation of defence responses, which depends on the precise cross-talk among different signalling pathways, has important consequences for plant fitness and is a new, challenging area of research. In this review we focus on new data relating to the physiological significance of different phyto-oxylipins and related enzymes. Moreover, recent advances in the biotechnological production of oxylipins are also discussed.
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Affiliation(s)
- Richard K Hughes
- John Innes Centre, Norwich Research Park, Norwich, Norfolk NR4 7UH, UK.
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211
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Chini A, Fonseca S, Chico JM, Fernández-Calvo P, Solano R. The ZIM domain mediates homo- and heteromeric interactions between Arabidopsis JAZ proteins. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2009; 59:77-87. [PMID: 19309455 DOI: 10.1111/j.1365-313x.2009.03852.x] [Citation(s) in RCA: 200] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Discovery of the jasmonate ZIM-domain (JAZ) repressors defined the core jasmonate (JA) signalling module as COI1-JAZ-MYC2, and allowed a full view of the JA signalling pathway from hormone perception to transcriptional reprogramming. JAZ proteins are repressors of MYC2 and targets of SCF(COI1), which is the likely jasmonate receptor. Upon hormone perception, JAZ repressors are degraded by the proteasome releasing MYC2 and allowing the activation of JA responses. All members of the JAZ family share two conserved domains, the Jas motif, required for JAZ interactions with MYC2 and COI1, and the ZIM domain, the function of which is so far unknown. Here, we show that the ZIM domain acts as a protein-protein interaction domain mediating homo- and heteromeric interactions between JAZ proteins. These JAZ-JAZ interactions are independent of the presence of the hormone. The observation that only a few members of the JAZ family form homo- and heteromers may suggest the relevance of these proteins in the regulation of JA signalling. Interestingly, the JAZ3DeltaJas protein interacts with several JAZ proteins, providing new clues to understanding the dominant JA insensitivity promoted by truncated JAZDeltaJas proteins. We also provide evidence that the Jas motif mediates the hormone-dependent interaction between Arabidopsis JAZ3 and COI1, and further confirm that the Jas motif is required and sufficient for Arabidopsis JAZ3-MYC2 interaction. Finally, we show that interaction with MYC2 is a common feature of the JAZ family, as most JAZ proteins can bind MYC2 in pull-down and yeast two-hybrid assays.
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Affiliation(s)
- Andrea Chini
- Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología-CSIC, Campus Universidad Autónoma, 28049 Madrid, Spain
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212
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Staswick PE. The tryptophan conjugates of jasmonic and indole-3-acetic acids are endogenous auxin inhibitors. PLANT PHYSIOLOGY 2009; 4:757-9. [PMID: 19458116 PMCID: PMC2705031 DOI: 10.1104/pp.109.138529] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Most conjugates of plant hormones are inactive, and some function to reduce the active hormone pool. This study characterized the activity of the tryptophan (Trp) conjugate of jasmonic acid (JA-Trp) in Arabidopsis (Arabidopsis thaliana). Unexpectedly, JA-Trp caused agravitropic root growth in seedlings, unlike JA or nine other JA-amino acid conjugates. The response was dose dependent from 1 to 100 microm, was independent of the COI1 jasmonate signaling locus, and unlike the jasmonate signal JA-isoleucine, JA-Trp minimally inhibited root growth. The Trp conjugate with indole-3-acetic acid (IAA-Trp) produced a similar response, while Trp alone and conjugates with benzoic and cinnamic acids did not. JA-Trp and IAA-Trp at 25 microm nearly eliminated seedling root inhibition caused by 2 microm IAA. The TIR1 auxin receptor is required for activity because roots of tir1-1 grew only approximately 60% of wild-type length on IAA plus JA-Trp, even though tir1-1 is auxin resistant. However, neither JA-Trp nor IAA-Trp interfered with IAA-dependent interaction between TIR1 and Aux/IAA7 in cell-free assays. Trp conjugates inhibited IAA-stimulated lateral root production and DR5-beta-glucuronidase gene expression. JA-deficient mutants were hypersensitive to IAA and a Trp-overaccumulating mutant was less sensitive, suggesting endogenous conjugates affect auxin sensitivity. Conjugates were present at 5.8 pmol g(-1) fresh weight or less in roots, seedlings, leaves, and flowers, and the values increased approximately 10-fold in roots incubated in 25 microm Trp and IAA or JA at 2 microm. These results show that JA-Trp and IAA-Trp constitute a previously unrecognized mechanism to regulate auxin action.
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Affiliation(s)
- Paul E Staswick
- Department of Agronomy and Horticulture, University of Nebraska, Lincoln, Nebraska 68583-0915, USA.
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213
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Wasternack C, Hause B. Emerging complexity: jasmonate-induced volatiles affect parasitoid choice. JOURNAL OF EXPERIMENTAL BOTANY 2009; 60:2451-2453. [PMID: 19498010 DOI: 10.1093/jxb/erp197] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Affiliation(s)
- Claus Wasternack
- Leibniz Institute of Plant Biochemistry, Weinberg 3, D-06120 Halle/Saale, Germany
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214
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Thatcher LF, Manners JM, Kazan K. Fusarium oxysporum hijacks COI1-mediated jasmonate signaling to promote disease development in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2009; 58:927-39. [PMID: 19220788 DOI: 10.1111/j.1365-313x.2009.03831.x] [Citation(s) in RCA: 181] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Although defense responses mediated by the plant oxylipin jasmonic acid (JA) are often necessary for resistance against pathogens with necrotrophic lifestyles, in this report we demonstrate that jasmonate signaling mediated through COI1 in Arabidopsis thaliana is responsible for susceptibility to wilt disease caused by the root-infecting fungal pathogen Fusarium oxysporum. Despite compromised JA-dependent defense responses, the JA perception mutant coronatine insensitive 1 (coi1), but not JA biosynthesis mutants, exhibited a high level of resistance to wilt disease caused by F. oxysporum. This response was independent from salicylic acid-dependent defenses, as coi1/NahG plants showed similar disease resistance to coi1 plants. Inoculation of reciprocal grafts made between coi1 and wild-type plants revealed that coi1-mediated resistance occurred primarily through the coi1 rootstock tissues. Furthermore, microscopy and quantification of fungal DNA during infection indicated that coi1-mediated resistance was not associated with reduced fungal penetration and colonization until a late stage of infection, when leaf necrosis was highly developed in wild-type plants. In contrast to wild-type leaves, coi1 leaves showed no necrosis following the application of F. oxysporum culture filtrate, and showed reduced expression of senescence-associated genes during disease development, suggesting that coi1 resistance is most likely achieved through the inhibition of F. oxysporum-incited lesion development and plant senescence. Together, our results indicate that F. oxysporum hijacks non-defensive aspects of the JA-signaling pathway to cause wilt-disease symptoms that lead to plant death in Arabidopsis.
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Affiliation(s)
- Louise F Thatcher
- CSIRO Plant Industry, Queensland Bioscience Precinct, St. Lucia, QLD 4067, Australia
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215
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Ballaré CL. Illuminated behaviour: phytochrome as a key regulator of light foraging and plant anti-herbivore defence. PLANT, CELL & ENVIRONMENT 2009; 32:713-25. [PMID: 19220784 DOI: 10.1111/j.1365-3040.2009.01958.x] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
In many ecological scenarios, the success of an individual plant is defined by the behavioural decisions that it makes when confronted with the risks of competition with other plants, and biomass losses to insect herbivores. These decisions involve expression of shade avoidance responses and induced chemical defences. Because these responses are costly, they frequently engender resource allocation dilemmas. In this review, I discuss the mechanisms that trigger adaptive responses to competitors and herbivores, highlighting the role of phytochromes as central organizers of the overall resource allocation strategy of plants. Phytochromes sense the reduction in the red to far-red (R : FR) ratio of sunlight caused by the proximity of other plants. Shade-intolerant plants respond to low R : FR ratios with shade avoidance behaviours and reduced investment in defence. Pfr depletion leads to increased stability of growth-promoting phytochrome-interacting factors (PIFs), and results in the production of auxins and gibberellins, degradation of DELLA proteins, which are repressors of PIFs, and reduced sensitivity to jasmonates. Thus, phytochrome appears to fulfil its organizational role by regulating the relative strength of the signalling circuits controlled by growth-related and defence-related hormones. I point out cases of signalling redundancy and discuss the significance of recent work on hormone signalling for our understanding of the mechanisms that control adaptive plant behaviour.
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Affiliation(s)
- Carlos L Ballaré
- IFEVA, Consejo Nacional de Investigaciones Científicas y Técnicas, and Universidad de Buenos Aires, Avenida San Martín 4453, C1417DSE Buenos Aires, Argentina.
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216
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Vandenborre G, Miersch O, Hause B, Smagghe G, Wasternack C, Van Damme EJM. Spodoptera littoralis-induced lectin expression in tobacco. PLANT & CELL PHYSIOLOGY 2009; 50:1142-55. [PMID: 19416954 DOI: 10.1093/pcp/pcp065] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The induced defense response in plants towards herbivores is mainly regulated by jasmonates and leads to the accumulation of so-called jasmonate-induced proteins. Recently, a jasmonate (JA) inducible lectin called Nicotiana tabacum agglutinin or NICTABA was discovered in tobacco (N. tabacum cv Samsun) leaves. Tobacco plants also accumulate the lectin after insect attack by caterpillars. To study the functional role of NICTABA, the accumulation of the JA precursor 12-oxophytodienoic acid (OPDA), JA as well as different JA metabolites were analyzed in tobacco leaves after herbivory by larvae of the cotton leafworm (Spodoptera littoralis) and correlated with NICTABA accumulation. It was shown that OPDA, JA as well as its methyl ester can trigger NICTABA accumulation. However, hydroxylation of JA and its subsequent sulfation and glucosylation results in inactive compounds that have lost the capacity to induce NICTABA gene expression. The expression profile of NICTABA after caterpillar feeding was recorded in local as well as in systemic leaves, and compared to the expression of several genes encoding defense proteins, and genes encoding a tobacco systemin and the allene oxide cyclase, an enzyme in JA biosynthesis. Furthermore, the accumulation of NICTABA was quantified after S. littoralis herbivory and immunofluorescence microscopy was used to study the localization of NICTABA in the tobacco leaf.
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Affiliation(s)
- Gianni Vandenborre
- Laboratory of Biochemistry and Glycobiology, Department of Molecular Biotechnology, Ghent University, Coupure Links 653, Ghent, Belgium
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217
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Mansfeld J. Plant phospholipases A2: perspectives on biotechnological applications. Biotechnol Lett 2009; 31:1373-80. [DOI: 10.1007/s10529-009-0034-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2009] [Revised: 04/30/2009] [Accepted: 05/06/2009] [Indexed: 01/21/2023]
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218
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Abstract
Plants induce long-lasting systemic immunity after local pathogen attack by emitting resistance-priming signals from infection sites. A number of plant molecules have been proposed as mobile factors for this response, but many do not fully satisfy criteria for timing and action in systemic immunity. Azelaic acid has been identified as a pathogen-induced metabolite in Arabidopsis vascular sap that has several properties of a long-distance resistance-priming signal.
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Affiliation(s)
- Jane E Parker
- Department of Plant-Microbe Interactions, Max Planck Institute for Plant Breeding Research, Carl-von-Linné Weg 10, 50829 Cologne, Germany.
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219
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Pieterse CMJ, Leon-Reyes A, Van der Ent S, Van Wees SCM. Networking by small-molecule hormones in plant immunity. Nat Chem Biol 2009; 5:308-16. [PMID: 19377457 DOI: 10.1038/nchembio.164] [Citation(s) in RCA: 1235] [Impact Index Per Article: 82.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Plants live in complex environments in which they intimately interact with a broad range of microbial pathogens with different lifestyles and infection strategies. The evolutionary arms race between plants and their attackers provided plants with a highly sophisticated defense system that, like the animal innate immune system, recognizes pathogen molecules and responds by activating specific defenses that are directed against the invader. Recent advances in plant immunity research have provided exciting new insights into the underlying defense signaling network. Diverse small-molecule hormones play pivotal roles in the regulation of this network. Their signaling pathways cross-communicate in an antagonistic or synergistic manner, providing the plant with a powerful capacity to finely regulate its immune response. Pathogens, on the other hand, can manipulate the plant's defense signaling network for their own benefit by affecting phytohormone homeostasis to antagonize the host immune response.
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Affiliation(s)
- Corné M J Pieterse
- Plant-Microbe Interactions, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands.
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220
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Schlink K. Identification and characterization of differentially expressed genes from Fagus sylvatica roots after infection with Phytophthora citricola. PLANT CELL REPORTS 2009; 28:873-882. [PMID: 19290528 DOI: 10.1007/s00299-009-0694-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2009] [Accepted: 03/01/2009] [Indexed: 05/27/2023]
Abstract
Phytophthora species are major plant pathogens infecting herbaceous and woody plants including European beech, the dominant or co-dominant tree in temperate Europe and an economically important species. For the analysis of the interaction of Phytophthora citricola with Fagus sylvatica suppression subtractive hybridization was used to isolate transcripts induced during infection and 1,149 sequences were generated. Hybridizations with driver and tester populations demonstrated differential expression in infected roots as compared to controls and verify efficient enrichment of these cDNAs during subtraction. Up regulation of selected genes during pathogenesis demonstrated using RT-PCR is consistent with these results. Pathogenesis-related proteins formed the largest group among functionally categorized transcripts. Cell wall proteins and protein kinases were also frequently found. Several transcription factors were isolated that are reactive to pathogens or wounding in other plants. The library contained a number of jasmonic acid, salicylic acid and ethylene responsive genes as well as genes directly involved in signaling pathways. Besides a mechanistic interconnection among signaling pathways another factor explaining the activation of different pathways could be the hemibiotrophic life style of Phytophthora triggering different signals in both stages.
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Affiliation(s)
- Katja Schlink
- Forest Genetics, Center of Life and Food Sciences Weihenstephan, Technische Universität München, Freising, Germany.
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221
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Pan X, Wang X. Profiling of plant hormones by mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci 2009; 877:2806-13. [PMID: 19427277 DOI: 10.1016/j.jchromb.2009.04.024] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2009] [Revised: 04/13/2009] [Accepted: 04/15/2009] [Indexed: 11/28/2022]
Abstract
Plant hormones regulate various aspects of plant growth and development, and different hormones may interact additively, synergistically, or antagonistically. Mass spectrometry has become a powerful tool for quantitative profiling of multiple classes of plant hormones because of its high sensitivity and selectivity. The capacity to simultaneously quantify multiple classes of phytohormones will facilitate the study of hormone function and cross-talk.
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Affiliation(s)
- Xiangqing Pan
- Department of Biology, University of Missouri, St. Louis, MO 63121, United States.
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222
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Somers DE, Fujiwara S. Thinking outside the F-box: novel ligands for novel receptors. TRENDS IN PLANT SCIENCE 2009; 14:206-13. [PMID: 19285909 DOI: 10.1016/j.tplants.2009.01.003] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2008] [Revised: 01/19/2009] [Accepted: 01/22/2009] [Indexed: 05/21/2023]
Abstract
The importance of regulated proteolysis in the physiology and development of plants is highlighted by the large number of genes dedicated to proteasome-dependent protein degradation. Within the SCF class of E3 ubiquitin ligases are more than 700 F-box proteins that act as recognition modules to specifically target their dedicated substrates for ubiquitylation. This review focuses on very recent studies indicating that some F-box proteins function as phytohormone or light receptors, which directly perceive signals and facilitate specific target-protein degradation to regulate downstream pathways. If this new connection between ligand-regulated proteolysis and signaling proves to be more extensive, an entirely new way of understanding the control of signal transduction is in the offing.
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Affiliation(s)
- David E Somers
- Department of Plant Cellular and Molecular Biology, The Ohio State University, 054 Rightmire Hall, 1060 Carmack Road, Columbus, OH 43210, USA.
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223
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Moreno JE, Tao Y, Chory J, Ballaré CL. Ecological modulation of plant defense via phytochrome control of jasmonate sensitivity. Proc Natl Acad Sci U S A 2009; 106:4935-40. [PMID: 19251652 PMCID: PMC2660767 DOI: 10.1073/pnas.0900701106] [Citation(s) in RCA: 203] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2008] [Indexed: 11/18/2022] Open
Abstract
For plants, the tradeoff between resource investment in defense and increased growth to out-compete neighbors creates an allocation dilemma. How plants resolve this dilemma, at the mechanistic level, is unclear. We found that Arabidopsis plants produced an attenuated defense phenotype under conditions of crowding and when exposed to far-red (FR) radiation, a light signal that plants use to detect the proximity of neighbors via the photoreceptor phytochrome. This phenotype was detectable through standard bioassays that measured the growth of Spodoptera frugiperda caterpillars. Two possible explanations for the effect of FR are: (i) a simple by-product of the diversion of resources to competition, and (ii) a specific effect of phytochrome on defense signaling. The first possibility was ruled out by the fact that the auxin-deficient sav3 mutant, which fails to induce growth responses to FR, still responded to FR with an attenuated defense phenotype. In support of the second hypothesis, we found that phytochrome inactivation by FR caused a strong reduction of plant sensitivity to jasmonates, which are key regulators of plant immunity. The effects of FR on jasmonate sensitivity were restricted to certain elements of the pathway. Supporting the idea that the FR effects on jasmonate signaling are functionally significant, we found that FR failed to increase tissue quality in jar1, a mutant impaired in jasmonate response. We conclude that the plant modulates its investment in defense as a function of the perceived risk of competition, and that this modulation is effected by phytochrome via selective desensitization to jasmonates.
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Affiliation(s)
- Javier E. Moreno
- Ifeva, Consejo Nacional de Investigaciones Científicas y Técnicas, and Universidad de Buenos Aires, Avenida San Martín 4453 C1417DSE Buenos Aires, Argentina; and
| | - Yi Tao
- The Howard Hughes Medical Institute, and Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037
| | - Joanne Chory
- The Howard Hughes Medical Institute, and Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037
| | - Carlos L. Ballaré
- Ifeva, Consejo Nacional de Investigaciones Científicas y Técnicas, and Universidad de Buenos Aires, Avenida San Martín 4453 C1417DSE Buenos Aires, Argentina; and
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224
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Abstract
Ethylene regulates several aspects of plant development, such as fruit ripening. In this issue of Genes & Development, Qiao and colleagues (pp. 512-521) report that the stability of the ethylene signaling protein EIN2 is modulated by two F-box proteins ETP1/2, reminiscent of the finding that another regulator of ethylene response, EIN3, is also targeted by the F-box proteins EBF1/2. ETP1/2 and EBF1/2 show distinct phylogenetic patterns, suggesting that they have different evolutionary constraints.
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Affiliation(s)
- Xuelu Wang
- State Key Laboratory of Genetic Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200433, China
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225
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Acharya BR, Assmann SM. Hormone interactions in stomatal function. PLANT MOLECULAR BIOLOGY 2009; 69:451-62. [PMID: 19031047 DOI: 10.1007/s11103-008-9427-0] [Citation(s) in RCA: 249] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2008] [Accepted: 10/27/2008] [Indexed: 05/20/2023]
Abstract
Research in recent years on the biology of guard cells has shown that these specialized cells integrate both extra- and intra-cellular signals in the control of stomatal apertures. Among the phytohormones, abscisic acid (ABA) is one of the key players regulating stomatal function. In addition, auxin, cytokinin, ethylene, brassinosteroids, jasmonates, and salicylic acid also contribute to stomatal aperture regulation. The interaction of multiple hormones can serve to determine the size of stomatal apertures in a condition-specific manner. Here, we discuss the roles of different phytohormones and the effects of their interactions on guard cell physiology and function.
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Affiliation(s)
- Biswa R Acharya
- Biology Department, Pennsylvania State University, 208 Mueller Laboratory, University Park, PA 16802, USA
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226
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Abstract
Ubiquitin-dependent protein degradation has emerged as a major pathway regulating eukaryotic biology. By employing a variety of ubiquitin ligases to target specific cellular proteins, the ubiquitin-proteasome system controls physiological processes in a highly regulated fashion. Recent studies on a plant hormone auxin have unveiled a novel paradigm of signal transduction in which ubiquitin ligases function as hormone receptors. Perceived by the F-box protein subunit of the SCF(TIR1) ubiquitin ligase, auxin directly promotes the recruitment of a family of transcriptional repressors for ubiquitination, thereby activating extensive transcriptional programs. Structural studies have revealed that auxin functions through a "molecular glue" mechanism to enhance protein-protein interactions with the assistance of another small molecule cofactor, inositol hexakisphosphate. Given the extensive repertoire of similar ubiquitin ligases in eukaryotic cells, this novel and widely adopted hormone-signaling mechanism in plants may also exist in other organisms.
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Affiliation(s)
- Xu Tan
- Dept. of Pharmacology, Box 357280, Univ. of Washington, Seattle, WA 98195, USA
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227
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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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228
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Clarke SM, Cristescu SM, Miersch O, Harren FJM, Wasternack C, Mur LAJ. Jasmonates act with salicylic acid to confer basal thermotolerance in Arabidopsis thaliana. THE NEW PHYTOLOGIST 2009; 182:175-187. [PMID: 19140948 DOI: 10.1111/j.1469-8137.2008.02735.x] [Citation(s) in RCA: 190] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
* The cpr5-1 Arabidopsis thaliana mutant exhibits constitutive activation of salicylic acid (SA), jasmonic acid (JA) and ethylene (ET) signalling pathways and displays enhanced tolerance of heat stress (HS). * cpr5-1 crossed with jar1-1 (a JA-amino acid synthetase) was compromised in basal thermotolerance, as were the mutants opr3 (mutated in OPDA reductase3) and coi1-1 (affected in an E3 ubiquitin ligase F-box; a key JA-signalling component). In addition, heating wild-type Arabidopsis led to the accumulation of a range of jasmonates: JA, 12-oxophytodienoic acid (OPDA) and a JA-isoleucine (JA-Ile) conjugate. Exogenous application of methyl jasmonate protected wild-type Arabidopsis from HS. * Ethylene was rapidly produced during HS, with levels being modulated by both JA and SA. By contrast, the ethylene mutant ein2-1 conferred greater thermotolerance. * These data suggest that JA acts with SA, conferring basal thermotolerance while ET may act to promote cell death.
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Affiliation(s)
- Shannon M Clarke
- Biochemistry Department, University of Otago, PO Box 56, Dunedin, New Zealand
- Present address: AgResearch Limited, Invermay Agricultural Centre, Puddle Alley, Private Bag 50034, Mosgiel, New Zealand
| | - Simona M Cristescu
- Life Science Trace Gas Exchange Facility, Department of Molecular and Laser Physics, Radboud University, Heyendaalseweg 135, NL 6525 AJ Nijmegen. The Netherlands
| | - Otto Miersch
- Leibniz-Institute of Plant Biochemistry, Weinberg 3, D-06120 Halle/Saale, Germany
| | - Frans J M Harren
- Life Science Trace Gas Exchange Facility, Department of Molecular and Laser Physics, Radboud University, Heyendaalseweg 135, NL 6525 AJ Nijmegen. The Netherlands
| | - Claus Wasternack
- Leibniz-Institute of Plant Biochemistry, Weinberg 3, D-06120 Halle/Saale, Germany
| | - Luis A J Mur
- Institute of Biological Sciences, University of Aberystwyth, SY23 3DA, UK
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229
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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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230
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Abstract
Since the discovery of the phosphoinositide/phospholipase C (PI/PLC) system in animal systems, we know that phospholipids are much more then just structural components of biological membranes. In the beginning, this idea was fairly straightforward. Receptor stimulation activates PLC, which hydrolyses phosphatidylinositol4,5-bisphosphate [PtdIns(4,5)P2] into two second messengers: inositol 1,4,5-trisphosphate (InsP3) and diacylglycerol (DG). While InsP3 difuses into the cytosol and triggers the release of calcium from an internal store via ligand-gated calcium channels, DG remains in the membrane where it recruits and activates members of the PKC family. The increase in calcium, together with the change in phosphorylation status, (in)activates a variety of protein targets, leading to a massive reprogramming, allowing the cell to appropriately respond to the extracellular stimulus. Later, it became obvious that not just PLC, but a variety of other phospholipid-metabolizing enzymes were activated, including phospholipase A, phospholipase D, and PI 3-kinase. More recently, it has become apparent that PtdIns4P and PtdIns(4,5)P2 are not just signal precursors but can also function as signaling molecules themselves. While plants contain most of the components described above, and evidence for their role in cell signaling is progressively increasing, major differences between plants and the mammalian paradigms exist. Below, these are described "in a nutshell."
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Affiliation(s)
- Teun Munnik
- Section of Plant Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam, NL-1098SM, Amsterdam, The Netherlands.
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