251
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Lambers H, Ahmedi I, Berkowitz O, Dunne C, Finnegan PM, Hardy GESJ, Jost R, Laliberté E, Pearse SJ, Teste FP. Phosphorus nutrition of phosphorus-sensitive Australian native plants: threats to plant communities in a global biodiversity hotspot. CONSERVATION PHYSIOLOGY 2013; 1:cot010. [PMID: 27293594 PMCID: PMC4732436 DOI: 10.1093/conphys/cot010] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 04/05/2013] [Accepted: 04/17/2013] [Indexed: 05/03/2023]
Abstract
South-western Australia harbours a global biodiversity hotspot on the world's most phosphorus (P)-impoverished soils. The greatest biodiversity occurs on the most severely nutrient-impoverished soils, where non-mycorrhizal species are a prominent component of the flora. Mycorrhizal species dominate where soils contain slightly more phosphorus. In addition to habitat loss and dryland salinity, a major threat to plant biodiversity in this region is eutrophication due to enrichment with P. Many plant species in the south-western Australian biodiversity hotspot are extremely sensitive to P, due to a low capability to down-regulate their phosphate-uptake capacity. Species from the most P-impoverished soils are also very poor competitors at higher P availability, giving way to more competitive species when soil P concentrations are increased. Sources of increased soil P concentrations include increased fire frequency, run-off from agricultural land, and urban activities. Another P source is the P-fertilizing effect of spraying natural environments on a landscape scale with phosphite to reduce the impacts of the introduced plant pathogen Phytophthora cinnamomi, which itself is a serious threat to biodiversity. We argue that alternatives to phosphite for P. cinnamomi management are needed urgently, and propose a strategy to work towards such alternatives, based on a sound understanding of the physiological and molecular mechanisms of the action of phosphite in plants that are susceptible to P. cinnamomi. The threats we describe for the south-western Australian biodiversity hotspot are likely to be very similar for other P-impoverished environments, including the fynbos in South Africa and the cerrado in Brazil.
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Affiliation(s)
- Hans Lambers
- School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Idriss Ahmedi
- School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
- Centre for Phytophthora Science and Management, School of Biological Sciences and Biotechnology, Murdoch University, Murdoch, WA 6150, Australia
| | - Oliver Berkowitz
- School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
- Centre for Phytophthora Science and Management, School of Biological Sciences and Biotechnology, Murdoch University, Murdoch, WA 6150, Australia
| | - Chris Dunne
- School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
- Science Division, Department of Environment and Conservation, Locked Bag 104, Bentley Delivery Centre, WA 6983, Australia
| | - Patrick M. Finnegan
- School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Giles E. St J. Hardy
- Centre for Phytophthora Science and Management, School of Biological Sciences and Biotechnology, Murdoch University, Murdoch, WA 6150, Australia
| | - Ricarda Jost
- School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Etienne Laliberté
- School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Stuart J. Pearse
- School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
- Astron Environmental Services, 129 Royal Street, East Perth, WA 6004, Australia
| | - François P. Teste
- School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
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252
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Mediation of seed provisioning in the transmission of environmental maternal effects in Maritime pine (Pinus pinaster Aiton). Heredity (Edinb) 2013; 111:248-55. [PMID: 23652562 DOI: 10.1038/hdy.2013.44] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Revised: 04/04/2013] [Accepted: 04/05/2013] [Indexed: 11/08/2022] Open
Abstract
Although maternal environmental effects are increasingly recognized as an important source of phenotypic variation with relevant impacts in evolutionary processes, their relevance in long-lived plants such as pine trees is largely unknown. Here, we used a powerful sample size and a strong quantitative genetic approach to analyse the sources of variation of early seedling performance and to identify seed mass (SM)-dependent and -independent maternal environmental effects in Maritime pine. We measured SM of 8924 individual seeds collected from 10 genotypes clonally replicated in two environments of contrasting quality (favourable and stressful), and we measured seedling growth rate and biomass allocation to roots and shoots. SM was extremely variable (up to 14-fold) and strongly determined by the maternal environment and the genotype of the mother tree. The favourable maternal environment led to larger cones, larger seeds and reduced SM variability. The maternal environment also determined the offspring phenotype, with seedlings coming from the favourable environment being 35% larger and with greater root/shoot ratio. Transgenerational plasticity appears, thus, to be a relevant source of phenotypic variation in the early performance of this pine species. Seed provisioning explained most of the effect of the maternal environment on seedling total biomass. Environmental maternal effects on seedling biomass allocation were, however, determined through SM-independent mechanisms, suggesting that other epigenetic regulation channels may be involved.
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253
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Chen X, Zhou DX. Rice epigenomics and epigenetics: challenges and opportunities. CURRENT OPINION IN PLANT BIOLOGY 2013; 16:164-9. [PMID: 23562565 DOI: 10.1016/j.pbi.2013.03.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Revised: 02/16/2013] [Accepted: 03/14/2013] [Indexed: 05/23/2023]
Abstract
During recent years rice genome-wide epigenomic information such as DNA methylation and histone modifications, which are important for genome activity has been accumulated. The function of a number of rice epigenetic regulators has been studied, many of which are found to be involved in a diverse range of developmental and stress-responsive pathways. Analysis of epigenetic variations among different rice varieties indicates that epigenetic modification may lead to inheritable phenotypic variation. Characterizing phenotypic consequences of rice epigenomic variations and the underlining chromatin mechanism and identifying epialleles related to important agronomic traits may provide novel strategies to enhance agronomically favorable traits and grain productivity in rice.
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Affiliation(s)
- Xiangsong Chen
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, 430070 Wuhan, China
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254
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Mandadi KK, Scholthof KBG. Plant immune responses against viruses: how does a virus cause disease? THE PLANT CELL 2013; 25:1489-505. [PMID: 23709626 PMCID: PMC3694688 DOI: 10.1105/tpc.113.111658] [Citation(s) in RCA: 230] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Plants respond to pathogens using elaborate networks of genetic interactions. Recently, significant progress has been made in understanding RNA silencing and how viruses counter this apparently ubiquitous antiviral defense. In addition, plants also induce hypersensitive and systemic acquired resistance responses, which together limit the virus to infected cells and impart resistance to the noninfected tissues. Molecular processes such as the ubiquitin proteasome system and DNA methylation are also critical to antiviral defenses. Here, we provide a summary and update of advances in plant antiviral immune responses, beyond RNA silencing mechanisms-advances that went relatively unnoticed in the realm of RNA silencing and nonviral immune responses. We also document the rise of Brachypodium and Setaria species as model grasses to study antiviral responses in Poaceae, aspects that have been relatively understudied, despite grasses being the primary source of our calories, as well as animal feed, forage, recreation, and biofuel needs in the 21st century. Finally, we outline critical gaps, future prospects, and considerations central to studying plant antiviral immunity. To promote an integrated model of plant immunity, we discuss analogous viral and nonviral immune concepts and propose working definitions of viral effectors, effector-triggered immunity, and viral pathogen-triggered immunity.
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255
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Jablonka E. Epigenetic inheritance and plasticity: The responsive germline. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2013; 111:99-107. [DOI: 10.1016/j.pbiomolbio.2012.08.014] [Citation(s) in RCA: 155] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2012] [Revised: 08/24/2012] [Accepted: 08/28/2012] [Indexed: 02/03/2023]
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256
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Walters DR, Ratsep J, Havis ND. Controlling crop diseases using induced resistance: challenges for the future. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:1263-80. [PMID: 23386685 DOI: 10.1093/jxb/ert026] [Citation(s) in RCA: 249] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
A number of different types of induced resistance have been defined based on differences in signalling pathways and spectra of effectiveness, including systemic acquired resistance and induced systemic resistance. Such resistance can be induced in plants by application of a variety of biotic and abiotic agents. The resulting resistance tends to be broad-spectrum and can be long-lasting, but is rarely complete, with most inducing agents reducing disease by between 20 and 85%. Since induced resistance is a host response, its expression under field conditions is likely to be influenced by a number of factors, including the environment, genotype, crop nutrition and the extent to which plants are already induced. Although research in this area has increased over the last few years, our understanding of the impact of these influences on the expression of induced resistance is still poor. There have also been a number of studies in recent years aimed at understanding of how best to use induced resistance in practical crop protection. However, such studies are relatively rare and further research geared towards incorporating induced resistance into disease management programmes, if appropriate, is required.
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Affiliation(s)
- Dale R Walters
- Crop & Soil Systems Research Group, SRUC, West Mains Road, Edinburgh EH9 3JG, UK.
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257
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Ballaré CL, Gross KL, Monson RK. Zooming in on plant interactions. Oecologia 2013; 171:601-3. [DOI: 10.1007/s00442-013-2621-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 02/05/2013] [Indexed: 02/01/2023]
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258
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Perkins LE, Cribb BW, Brewer PB, Hanan J, Grant M, de Torres M, Zalucki MP. Generalist insects behave in a jasmonate-dependent manner on their host plants, leaving induced areas quickly and staying longer on distant parts. Proc Biol Sci 2013; 280:20122646. [PMID: 23390101 DOI: 10.1098/rspb.2012.2646] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Plants are sessile, so have evolved sensitive ways to detect attacking herbivores and sophisticated strategies to effectively defend themselves. Insect herbivory induces synthesis of the phytohormone jasmonic acid which activates downstream metabolic pathways for various chemical defences such as toxins and digestion inhibitors. Insects are also sophisticated animals, and many have coevolved physiological adaptations that negate this induced plant defence. Insect behaviour has rarely been studied in the context of induced plant defence, although behavioural adaptation to induced plant chemistry may allow insects to bypass the host's defence system. By visualizing jasmonate-responsive gene expression within whole plants, we uncovered spatial and temporal limits to the systemic spread of plant chemical defence following herbivory. By carefully tracking insect movement, we found induced changes in plant chemistry were detected by generalist Helicoverpa armigera insects which then modified their behaviour in response, moving away from induced parts and staying longer on uninduced parts of the same plant. This study reveals that there are plant-wide signals rapidly generated following herbivory that allow insects to detect the heterogeneity of plant chemical defences. Some insects use these signals to move around the plant, avoiding localized sites of induction and staying ahead of induced toxic metabolites.
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Affiliation(s)
- Lynda E Perkins
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia.
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259
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Migicovsky Z, Kovalchuk I. Changes to DNA methylation and homologous recombination frequency in the progeny of stressed plants. Biochem Cell Biol 2013; 91:1-5. [PMID: 23442135 DOI: 10.1139/bcb-2012-0046] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Plants undergo changes in response to biotic and abiotic stresses that help them adjust and survive. Some of these changes may even be passed on to progeny and eventually lead to adaptive evolution. Transgenerational changes in response to stress include alterations in DNA methylation and changes in homologous recombination frequency (HRF). The progeny of plants that were stressed often show elevated HRF as well as genomic hypermethylation, although specific loci that are beneficial in times of stress may be hypomethylated. One of the possible mechanisms responsible for passing the memory to the progeny involves small interfering RNAs; Dicer-like proteins, DCL2 and DCL3, are in part required for this process. However, while epigenetic modifications are often present in the untreated progeny of stressed plants, they are not usually sustained for multiple unexposed generations. Still, transgenerational inheritance of such changes has already begun to provide evidence for an important role of epigenetics in enhancing stress resistance.
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Affiliation(s)
- Zoë Migicovsky
- University of Lethbridge, Department of Biological Sciences, Lethbridge, AB T1K 3M4, Canada
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260
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Fu ZQ, Dong X. Systemic acquired resistance: turning local infection into global defense. ANNUAL REVIEW OF PLANT BIOLOGY 2013; 64:839-63. [PMID: 23373699 DOI: 10.1146/annurev-arplant-042811-105606] [Citation(s) in RCA: 796] [Impact Index Per Article: 72.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Systemic acquired resistance (SAR) is an induced immune mechanism in plants. Unlike vertebrate adaptive immunity, SAR is broad spectrum, with no specificity to the initial infection. An avirulent pathogen causing local programmed cell death can induce SAR through generation of mobile signals, accumulation of the defense hormone salicylic acid, and secretion of the antimicrobial PR (pathogenesis-related) proteins. Consequently, the rest of the plant is protected from secondary infection for a period of weeks to months. SAR can even be passed on to progeny through epigenetic regulation. The Arabidopsis NPR1 (nonexpresser of PR genes 1) protein is a master regulator of SAR. Recent study has shown that salicylic acid directly binds to the NPR1 adaptor proteins NPR3 and NPR4, regulates their interactions with NPR1, and controls NPR1 protein stability. However, how NPR1 interacts with TGA transcription factors to activate defense gene expression is still not well understood. In addition, redox regulators, the mediator complex, WRKY transcription factors, endoplasmic reticulum-resident proteins, and DNA repair proteins play critical roles in SAR.
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Affiliation(s)
- Zheng Qing Fu
- Howard Hughes Medical Institute-Gordon and Betty Moore Foundation and Department of Biology, Duke University, Durham, NC 27708, USA
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261
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Shah J, Zeier J. Long-distance communication and signal amplification in systemic acquired resistance. FRONTIERS IN PLANT SCIENCE 2013; 4:30. [PMID: 23440336 PMCID: PMC3579191 DOI: 10.3389/fpls.2013.00030] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 02/06/2013] [Indexed: 05/18/2023]
Abstract
Systemic acquired resistance (SAR) is an inducible defense mechanism in plants that confers enhanced resistance against a variety of pathogens. SAR is activated in the uninfected systemic (distal) organs in response to a prior (primary) infection elsewhere in the plant. SAR is associated with the activation of salicylic acid (SA) signaling and the priming of defense responses for robust activation in response to subsequent infections. The activation of SAR requires communication by the primary infected tissues with the distal organs. The vasculature functions as a conduit for the translocation of factors that facilitate long-distance intra-plant communication. In recent years, several metabolites putatively involved in long-distance signaling have been identified. These include the methyl ester of SA (MeSA), the abietane diterpenoid dehydroabietinal (DA), the dicarboxylic acid azelaic acid (AzA), and a glycerol-3-phosphate (G3P)-dependent factor. Long-distance signaling by some of these metabolites also requires the lipid-transfer protein DIR1 (DEFECTIVE IN INDUCED RESISTANCE 1). The relative contribution of these factors in long-distance signaling is likely influenced by environmental conditions, for example light. In the systemic leaves, the AGD2-LIKE DEFENSE RESPONSE PROTEIN1 (ALD1)-dependent production of the lysine catabolite pipecolic acid (Pip), FLAVIN-DEPENDENT MONOOXYGENASE1 (FMO1) signaling, as well as SA synthesis and downstream signaling are required for the activation of SAR. This review summarizes the involvement and interaction between long-distance SAR signals and details the recently discovered role of Pip in defense amplification and priming that allows plants to acquire immunity at the systemic level. Recent advances in SA signaling and perception are also highlighted.
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Affiliation(s)
- Jyoti Shah
- Department of Biological Sciences, University of North TexasDenton, TX, USA
- *Correspondence: Jyoti Shah, Department of Biological Sciences, University of North Texas, Life Sciences Building-B, Room # 418, 1155 Union Circle #305220, Denton, TX 76203, USA. e-mail:
| | - Jürgen Zeier
- Department of Biology, Heinrich-Heine-UniversityDüsseldorf, Germany
- Jürgen Zeier, Department of Biology, Heinrich-Heine-University, 40225 Düsseldorf, Germany. e-mail:
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262
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Shah J, Zeier J. Long-distance communication and signal amplification in systemic acquired resistance. FRONTIERS IN PLANT SCIENCE 2013. [PMID: 23440336 DOI: 10.3390/fpls.2013.00030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Systemic acquired resistance (SAR) is an inducible defense mechanism in plants that confers enhanced resistance against a variety of pathogens. SAR is activated in the uninfected systemic (distal) organs in response to a prior (primary) infection elsewhere in the plant. SAR is associated with the activation of salicylic acid (SA) signaling and the priming of defense responses for robust activation in response to subsequent infections. The activation of SAR requires communication by the primary infected tissues with the distal organs. The vasculature functions as a conduit for the translocation of factors that facilitate long-distance intra-plant communication. In recent years, several metabolites putatively involved in long-distance signaling have been identified. These include the methyl ester of SA (MeSA), the abietane diterpenoid dehydroabietinal (DA), the dicarboxylic acid azelaic acid (AzA), and a glycerol-3-phosphate (G3P)-dependent factor. Long-distance signaling by some of these metabolites also requires the lipid-transfer protein DIR1 (DEFECTIVE IN INDUCED RESISTANCE 1). The relative contribution of these factors in long-distance signaling is likely influenced by environmental conditions, for example light. In the systemic leaves, the AGD2-LIKE DEFENSE RESPONSE PROTEIN1 (ALD1)-dependent production of the lysine catabolite pipecolic acid (Pip), FLAVIN-DEPENDENT MONOOXYGENASE1 (FMO1) signaling, as well as SA synthesis and downstream signaling are required for the activation of SAR. This review summarizes the involvement and interaction between long-distance SAR signals and details the recently discovered role of Pip in defense amplification and priming that allows plants to acquire immunity at the systemic level. Recent advances in SA signaling and perception are also highlighted.
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Affiliation(s)
- Jyoti Shah
- Department of Biological Sciences, University of North Texas Denton, TX, USA
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263
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Sharma A. Transgenerational epigenetic inheritance: focus on soma to germline information transfer. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2012; 113:439-46. [PMID: 23257323 DOI: 10.1016/j.pbiomolbio.2012.12.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 11/30/2012] [Accepted: 12/06/2012] [Indexed: 01/29/2023]
Abstract
In trangenerational epigenetic inheritance, phenotypic information not encoded in DNA sequence is transmitted across generations. In germline-dependent mode, memory of environmental exposure in parental generation is transmitted through gametes, leading to appearance of phenotypes in the unexposed future generations. The memory is considered to be encoded in epigenetic factors like DNA methylation, histone modifications and regulatory RNAs. Environmental exposure may cause epigenetic modifications in the germline either directly or indirectly through primarily affecting the soma. The latter possibility is most intriguing because it contradicts the established dogma that hereditary information flows only from germline to soma, not in reverse. As such, identification of the factor(s) mediating soma to germline information transfer in transgenerational epigenetic inheritance would be pathbreaking. Regulatory RNAs and hormone have previously been implicated or proposed to play a role in soma to germline communication in epigenetic inheritance. This review examines the recent examples of gametogenic transgenerational inheritance in plants and animals in order to assess if evidence of regulatory RNAs and hormones as mediators of information transfer is supported. Overall, direct evidence for both mobile regulatory RNAs and hormones is found to exist in plants. In animals, although involvement of mobile RNAs seems imminent, direct evidence of RNA-mediated soma to germline information transfer in transgenerational epigenetic inheritance is yet to be obtained. Direct evidence is also lacking for hormones in animals. However, detailed examination of recently reported examples of transgenerational inheritance reveals circumstantial evidence supporting a role of hormones in information transmission.
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Affiliation(s)
- Abhay Sharma
- CSIR-Institute of Genomics and Integrative Biology, Council of Scientific and Industrial Research, Delhi University Campus, Mall Road, Delhi 110007, India.
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264
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Dorantes-Acosta AE, Sánchez-Hernández CV, Arteaga-Vázquez MA. Biotic stress in plants: life lessons from your parents and grandparents. Front Genet 2012; 3:256. [PMID: 23230448 PMCID: PMC3515780 DOI: 10.3389/fgene.2012.00256] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Accepted: 10/31/2012] [Indexed: 12/27/2022] Open
Affiliation(s)
- A E Dorantes-Acosta
- Laboratorio de Epigenética y Biología del Desarrollo, Instituto de Biotecnología y Ecología Aplicada(INBIOTECA), Universidad Veracruzana. Xalapa, Veracruz. México
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265
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Mirouze M. The Small RNA-Based Odyssey of Epigenetic Information in Plants: From Cells to Species. DNA Cell Biol 2012; 31:1650-6. [DOI: 10.1089/dna.2012.1681] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Marie Mirouze
- Institut de Recherche pour le Développement, UMR232, ERL5300 IRD UM2 CNRS, Montpellier, France
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266
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Gutzat R, Mittelsten Scheid O. Epigenetic responses to stress: triple defense? CURRENT OPINION IN PLANT BIOLOGY 2012; 15:568-73. [PMID: 22960026 PMCID: PMC3508409 DOI: 10.1016/j.pbi.2012.08.007] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Accepted: 08/16/2012] [Indexed: 05/19/2023]
Abstract
Stressful conditions for plants can originate from numerous physical, chemical and biological factors, and plants have developed a plethora of survival strategies including developmental and morphological adaptations, specific signaling and defense pathways as well as innate and acquired immunity. While it has become clear in recent years that many stress responses involve epigenetic components, we are far from understanding the mechanisms and molecular interactions. Extending our knowledge is fundamental, not least for plant breeding and conservation biology. This review will highlight recent insights into epigenetic stress responses at the level of signaling, chromatin modification, and potentially heritable consequences.
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267
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Abstract
The biological and medical importance of epigenetics is nowtaken for granted, but the significance of one aspect of it—epigenetic inheritance—is less widely recognized. New datasuggest that not only is it ubiquitous, but both the generationand the transmission of epigenetic variations may be affectedby developmental conditions. Population studies, formalmodels, and research on genomic and ecological stressesall suggest that epigenetic inheritance is important in bothmicro-and macroevolutionary change.
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268
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Tian D, Tooker J, Peiffer M, Chung SH, Felton GW. Role of trichomes in defense against herbivores: comparison of herbivore response to woolly and hairless trichome mutants in tomato (Solanum lycopersicum). PLANTA 2012; 236:1053-66. [PMID: 22552638 DOI: 10.1007/s00425-012-1651-9] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Accepted: 04/08/2012] [Indexed: 05/18/2023]
Abstract
Trichomes contribute to plant resistance against herbivory by physical and chemical deterrents. To better understand their role in plant defense, we systemically studied trichome morphology, chemical composition and the response of the insect herbivores Helicoverpa zea and Leptinotarsa decemlineata (Colorado potato beetle = CPB) on the tomato hairless (hl), hairy (woolly) mutants and wild-type Rutgers (RU) and Alisa Craig (AC) plants. Hairless mutants showed reduced number of twisted glandular trichomes (types I, IV, VI and VII) on leaf and stem compared to wild-type Rutgers (RU), while woolly mutants showed high density of non-glandular trichomes (types II, III and V) but only on the leaf. In both mutants, trichome numbers were increased by methyl jasmonate (MeJA), but the types of trichomes present were not affected by MeJA treatment. Glandular trichomes contained high levels of monoterpenes and sesquiterpenes. A similar pattern of transcript accumulation was observed for monoterpene MTS1 (=TPS5) and sesquiterpene synthase SST1 (=TPS9) genes in trichomes. While high density of non-glandular trichome on leaves negatively influenced CPB feeding behavior and growth, it stimulated H. zea growth. High glandular trichome density impaired H. zea growth, but had no effect on CPB. Quantitative real-time polymerase chain reaction (qRT-PCR) showed that glandular trichomes highly express protein inhibitors (PIN2), polyphenol oxidase (PPOF) and hydroperoxide lyase (HPL) when compared to non-glandular trichomes. The SlCycB2 gene, which participates in woolly trichome formation, was highly expressed in the woolly mutant trichomes. PIN2 in trichomes was highly induced by insect feeding in both mutant and wild-type plants. Thus, both the densities of trichomes and the chemical defenses residing in the trichomes are inducible.
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Affiliation(s)
- Donglan Tian
- Department of Entomology, Center for Chemical Ecology, Penn State University, University Park, PA 16802, USA
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269
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Transgenerational defense induction and epigenetic inheritance in plants. Trends Ecol Evol 2012; 27:618-26. [PMID: 22940222 DOI: 10.1016/j.tree.2012.07.011] [Citation(s) in RCA: 220] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Revised: 07/12/2012] [Accepted: 07/15/2012] [Indexed: 11/23/2022]
Abstract
Rapidly accumulating evidence shows that herbivore and pathogen attack of plants can generate particular defense phenotypes across generations. What was once thought to be an oddity of plant defense induction now appears to be a taxonomically widespread phenomenon with strong potential to impact the ecology and evolution of species interactions. DNA methylation, histone modifications, and small RNAs each contribute to transgenerational defense initiation; examples in several species demonstrate that this induction can last for multiple generations. Priming of the offspring generation for more rapid induction following subsequent attack has also been reported. The extent to which transgenerational induction is predictable, detectable in nature, and subject to manipulation will determine the ability of researchers to decipher its role in plant-herbivore and plant-pathogen interactions.
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270
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Verhoeven KJF, van Gurp TP. Transgenerational effects of stress exposure on offspring phenotypes in apomictic dandelion. PLoS One 2012; 7:e38605. [PMID: 22723869 PMCID: PMC3377677 DOI: 10.1371/journal.pone.0038605] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Accepted: 05/11/2012] [Indexed: 01/16/2023] Open
Abstract
Heritable epigenetic modulation of gene expression is a candidate mechanism to explain parental environmental effects on offspring phenotypes, but current evidence for environment-induced epigenetic changes that persist in offspring generations is scarce. In apomictic dandelions, exposure to various stresses was previously shown to heritably alter DNA methylation patterns. In this study we explore whether these induced changes are accompanied by heritable effects on offspring phenotypes. We observed effects of parental jasmonic acid treatment on offspring specific leaf area and on offspring interaction with a generalist herbivore; and of parental nutrient stress on offspring root-shoot biomass ratio, tissue P-content and leaf morphology. Some of the effects appeared to enhance offspring ability to cope with the same stresses that their parents experienced. Effects differed between apomictic genotypes and were not always consistently observed between different experiments, especially in the case of parental nutrient stress. While this context-dependency of the effects remains to be further clarified, the total set of results provides evidence for the existence of transgenerational effects in apomictic dandelions. Zebularine treatment affected the within-generation response to nutrient stress, pointing at a role of DNA methylation in phenotypic plasticity to nutrient environments. This study shows that stress exposure in apomictic dandelions can cause transgenerational phenotypic effects, in addition to previously demonstrated transgenerational DNA methylation effects.
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Affiliation(s)
- Koen J F Verhoeven
- Department of Terrestrial Ecology, Netherlands Institute of Ecology, Wageningen, The Netherlands.
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271
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Walters DR, Paterson L. Parents lend a helping hand to their offspring in plant defence. Biol Lett 2012; 8:871-3. [PMID: 22696290 DOI: 10.1098/rsbl.2012.0416] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Plants under attack by pathogens and pests can mount a range of inducible defences, encompassing both chemical and structural changes. Although few reports exist, it appears that plants responding to pathogen or herbivore attack, or chemical defence elicitors, may produce progeny that are better able to defend themselves against attack, compared with progeny from unthreatened or untreated plants. To date, all research on transgenerational effects of biotic stress has been conducted on dicotyledenous plants. We examined the possibility that resistance induced by application of chemical defence elicitors to the monocot plant barley, could be passed on to the progeny. Plants were treated with acibenzolar-S-methyl (ASM) or saccharin, and grain harvested at maturity. Germination was unaffected in seed collected from plants treated with saccharin, while germination was reduced significantly in seed collected from ASM-treated plants. The subsequent growth of the seedlings was not significantly different in any of the treatments. However, plants from parents treated with both ASM or saccharin exhibited significantly enhanced resistance to infection by Rhynchosporium commune, despite not being treated with elicitor themselves. These data hint at the possibility of producing disease-resistant plants by exposing parent plants to chemical elicitors.
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Affiliation(s)
- Dale R Walters
- Crop and Soil Systems Research Group, Scottish Agricultural College, King's Buildings, West Mains Road, Edinburgh EH9 3JG, UK.
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272
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Luna E, Ton J. The epigenetic machinery controlling transgenerational systemic acquired resistance. PLANT SIGNALING & BEHAVIOR 2012; 7:615-8. [PMID: 22580690 PMCID: PMC3442853 DOI: 10.4161/psb.20155] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Progeny from diseased Arabidopsis shows enhanced resistance, which is associated with priming of defense genes. This transgenerational systemic acquired resistance (SAR) is effective against biotrophic pathogens, such as the downy mildew pathogen Hyaloperonospora arabidopsidis. In this study, we have examined mutants in RNA-directed DNA methylation (RdDM) for transgenerational SAR. Our analysis suggests that transgenerational SAR is regulated by the RdDM pathway and transmitted by hypomethylation at CpNpG sites.
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Affiliation(s)
- Estrella Luna
- The University of Sheffield, Department of Animal and Plant Sciences, UK
- The Lancaster Environmental Centre, Lancaster University, UK
| | - Jurriaan Ton
- The University of Sheffield, Department of Animal and Plant Sciences, UK
- Correspondence to: Jurriaan Ton,
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273
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Jung SC, Martinez-Medina A, Lopez-Raez JA, Pozo MJ. Mycorrhiza-induced resistance and priming of plant defenses. J Chem Ecol 2012. [PMID: 22623151 DOI: 10.1007/s10886‐012‐0134‐6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Symbioses between plants and beneficial soil microorganisms like arbuscular-mycorrhizal fungi (AMF) are known to promote plant growth and help plants to cope with biotic and abiotic stresses. Profound physiological changes take place in the host plant upon root colonization by AMF affecting the interactions with a wide range of organisms below- and above-ground. Protective effects of the symbiosis against pathogens, pests, and parasitic plants have been described for many plant species, including agriculturally important crop varieties. Besides mechanisms such as improved plant nutrition and competition, experimental evidence supports a major role of plant defenses in the observed protection. During mycorrhiza establishment, modulation of plant defense responses occurs thus achieving a functional symbiosis. As a consequence of this modulation, a mild, but effective activation of the plant immune responses seems to occur, not only locally but also systemically. This activation leads to a primed state of the plant that allows a more efficient activation of defense mechanisms in response to attack by potential enemies. Here, we give an overview of the impact on interactions between mycorrhizal plants and pathogens, herbivores, and parasitic plants, and we summarize the current knowledge of the underlying mechanisms. We focus on the priming of jasmonate-regulated plant defense mechanisms that play a central role in the induction of resistance by arbuscular mycorrhizas.
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Affiliation(s)
- Sabine C Jung
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín (EEZ), CSIC, Prof. Albareda 1, 18008, Granada, Spain
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274
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Jung SC, Martinez-Medina A, Lopez-Raez JA, Pozo MJ. Mycorrhiza-induced resistance and priming of plant defenses. J Chem Ecol 2012; 38:651-64. [PMID: 22623151 DOI: 10.1007/s10886-012-0134-6] [Citation(s) in RCA: 398] [Impact Index Per Article: 33.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Revised: 04/27/2012] [Accepted: 05/01/2012] [Indexed: 11/25/2022]
Abstract
Symbioses between plants and beneficial soil microorganisms like arbuscular-mycorrhizal fungi (AMF) are known to promote plant growth and help plants to cope with biotic and abiotic stresses. Profound physiological changes take place in the host plant upon root colonization by AMF affecting the interactions with a wide range of organisms below- and above-ground. Protective effects of the symbiosis against pathogens, pests, and parasitic plants have been described for many plant species, including agriculturally important crop varieties. Besides mechanisms such as improved plant nutrition and competition, experimental evidence supports a major role of plant defenses in the observed protection. During mycorrhiza establishment, modulation of plant defense responses occurs thus achieving a functional symbiosis. As a consequence of this modulation, a mild, but effective activation of the plant immune responses seems to occur, not only locally but also systemically. This activation leads to a primed state of the plant that allows a more efficient activation of defense mechanisms in response to attack by potential enemies. Here, we give an overview of the impact on interactions between mycorrhizal plants and pathogens, herbivores, and parasitic plants, and we summarize the current knowledge of the underlying mechanisms. We focus on the priming of jasmonate-regulated plant defense mechanisms that play a central role in the induction of resistance by arbuscular mycorrhizas.
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Affiliation(s)
- Sabine C Jung
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín (EEZ), CSIC, Prof. Albareda 1, 18008, Granada, Spain
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275
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Pecinka A, Mittelsten Scheid O. Stress-induced chromatin changes: a critical view on their heritability. PLANT & CELL PHYSIOLOGY 2012; 53:801-8. [PMID: 22457398 PMCID: PMC3345370 DOI: 10.1093/pcp/pcs044] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Accepted: 03/17/2012] [Indexed: 05/19/2023]
Abstract
The investigation of stress responses has been a focus of plant research, breeding and biotechnology for a long time. Insight into stress perception, signaling and genetic determinants of resistance has recently been complemented by growing evidence for substantial stress-induced changes at the chromatin level. These affect specific sequences or occur genome-wide and are often correlated with transcriptional regulation. The majority of these changes only occur during stress exposure, and both expression and chromatin states typically revert to the pre-stress state shortly thereafter. Other changes result in the maintenance of new chromatin states and modified gene expression for a longer time after stress exposure, preparing an individual for developmental decisions or more effective defence. Beyond this, there are claims for stress-induced heritable chromatin modifications that are transmitted to progeny, thereby improving their characteristics. These effects resemble the concept of Lamarckian inheritance of acquired characters and represent a challenge to the uniqueness of DNA sequence-based inheritance. However, with the growing insight into epigenetic regulation and transmission of chromatin states, it is worth investigating these phenomena carefully. While genetic changes (mainly transposon mobility) in response to stress-induced interference with chromatin are well documented and heritable, in our view there is no unambiguous evidence for transmission of exclusively chromatin-controlled stress effects to progeny. We propose a set of criteria that should be applied to substantiate the data for stress-induced, chromatin-encoded new traits. Well-controlled stress treatments, thorough phenotyping and application of refined genome-wide epigenetic analysis tools should be helpful in moving from interesting observations towards robust evidence.
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Affiliation(s)
- Ales Pecinka
- Max Planck Institute for Plant Breeding Research, Cologne, Germany.
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276
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Tian D, Peiffer M, Shoemaker E, Tooker J, Haubruge E, Francis F, Luthe DS, Felton GW. Salivary glucose oxidase from caterpillars mediates the induction of rapid and delayed-induced defenses in the tomato plant. PLoS One 2012; 7:e36168. [PMID: 22558369 PMCID: PMC3340365 DOI: 10.1371/journal.pone.0036168] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Accepted: 04/02/2012] [Indexed: 01/09/2023] Open
Abstract
Caterpillars produce oral secretions that may serve as cues to elicit plant defenses, but in other cases these secretions have been shown to suppress plant defenses. Ongoing work in our laboratory has focused on the salivary secretions of the tomato fruitworm, Helicoverpa zea. In previous studies we have shown that saliva and its principal component glucose oxidase acts as an effector by suppressing defenses in tobacco. In this current study, we report that saliva elicits a burst of jasmonic acid (JA) and the induction of late responding defense genes such as proteinase inhibitor 2 (Pin2). Transcripts encoding early response genes associated with the JA pathway were not affected by saliva. We also observed a delayed response to saliva with increased densities of Type VI glandular trichomes in newly emerged leaves. Proteomic analysis of saliva revealed glucose oxidase (GOX) was the most abundant protein identified and we confirmed that it plays a primary role in the induction of defenses in tomato. These results suggest that the recognition of GOX in tomato may represent a case for effector-triggered immunity. Examination of saliva from other caterpillar species indicates that saliva from the noctuids Spodoptera exigua and Heliothis virescens also induced Pin2 transcripts.
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Affiliation(s)
- Donglan Tian
- Department of Entomology, Center for Chemical Ecology, Penn State University, University Park, Pennsylvania, United States of America
| | - Michelle Peiffer
- Department of Entomology, Center for Chemical Ecology, Penn State University, University Park, Pennsylvania, United States of America
| | - Erica Shoemaker
- Department of Entomology, Center for Chemical Ecology, Penn State University, University Park, Pennsylvania, United States of America
| | - John Tooker
- Department of Entomology, Center for Chemical Ecology, Penn State University, University Park, Pennsylvania, United States of America
| | - Eric Haubruge
- Functional and Evolutionary Entomology, Gembloux Agro-Bio Tech, University of Liege, Liege, Belgium
| | - Frederic Francis
- Functional and Evolutionary Entomology, Gembloux Agro-Bio Tech, University of Liege, Liege, Belgium
| | - Dawn S. Luthe
- Department of Entomology, Center for Chemical Ecology, Penn State University, University Park, Pennsylvania, United States of America
- Department of Crop and Soil Science, Center for Chemical Ecology, Penn State University, University Park, Pennsylvania, United States of America
| | - Gary W. Felton
- Department of Entomology, Center for Chemical Ecology, Penn State University, University Park, Pennsylvania, United States of America
- * E-mail:
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277
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Berr A, Ménard R, Heitz T, Shen WH. Chromatin modification and remodelling: a regulatory landscape for the control of Arabidopsis defence responses upon pathogen attack. Cell Microbiol 2012; 14:829-39. [DOI: 10.1111/j.1462-5822.2012.01785.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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278
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Rasmann S, De Vos M, Jander G. Ecological role of transgenerational resistance against biotic threats. PLANT SIGNALING & BEHAVIOR 2012; 7:447-9. [PMID: 22499174 PMCID: PMC3419029 DOI: 10.4161/psb.19525] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Plants in their natural environments are constantly subjected to biotic stress. In addition to possessing physical barriers and anti-nutritive toxins, plants can be primed to respond more efficiently against future attack via faster and stronger gene activation. Here we discuss recent findings showing that plants can pass signatures of attack to the next generation, thus rendering the progeny more resistant against insect and pathogen attack. A combination of phytohormone signaling, small RNA-mediated gene silencing and DNA methylation are involved in transgenerational induced resistance. Epiallelic variation against biotic threats should be under positive selection in populations of plants where the environment is predictable over time. Similarly, in very genetically homogenous populations, such as during range expansion, epigenome reorganization is a likely mechanism for faster plant adaptation to novel biotic attack. Further research is needed to understand the relative role of the genome vs. the epigenome for the evolution of increased plant resistance.
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Affiliation(s)
- Sergio Rasmann
- Ecology and Evolution, University of Lausanne, Lausanne, Switzerland.
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279
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Stevens MT, Gusse AC, Lindroth RL. Genotypic Differences and Prior Defoliation Affect Re-Growth and Phytochemistry after Coppicing in Populus tremuloides. J Chem Ecol 2012; 38:306-14. [DOI: 10.1007/s10886-012-0081-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Revised: 02/09/2012] [Accepted: 02/14/2012] [Indexed: 11/29/2022]
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280
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Slaughter A, Daniel X, Flors V, Luna E, Hohn B, Mauch-Mani B. Descendants of primed Arabidopsis plants exhibit resistance to biotic stress. PLANT PHYSIOLOGY 2012. [PMID: 22209872 DOI: 10.1104/pp.111.191593pp.111.191593] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
An attack of plants by pathogens or treatment with certain resistance-inducing compounds can lead to the establishment of a unique primed state of defense. Primed plants show enhanced defense reactions upon further challenge with biotic or abiotic stress. Here, we report that the primed state in Arabidopsis (Arabidopsis thaliana) is still functional in the next generation without additional treatment. We compared the reactions of Arabidopsis plants that had been either primed with β-amino-butyric acid (BABA) or with an avirulent isolate of the bacteria Pseudomonas syringae pv tomato (PstavrRpt2). The descendants of primed plants showed a faster and higher accumulation of transcripts of defense-related genes in the salicylic acid signaling pathway and enhanced disease resistance upon challenge inoculation with a virulent isolate of P. syringae. In addition, the progeny of primed plants was also more resistant against the oomycete pathogen Hyaloperonospora arabidopsidis. When transgenerationally primed plants were subjected to an additional priming treatment, their descendants displayed an even stronger primed phenotype, suggesting that plants can inherit a sensitization for the priming phenomenon. Interestingly, this primed to be primed phenotype was much reduced in the Arabidopsis β-amino-butyric acid priming mutant ibs1 (induced BABA sterility1). Our results demonstrate that the primed state of plants is transferred to their progeny and confers improved protection from pathogen attack as compared to the descendants of unprimed plants.
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Affiliation(s)
- Ana Slaughter
- Laboratoire de Biologie Moléculaire et Cellulaire, Institut de Biologie, Université de Neuchâtel, 2009 Neuchâtel, Switzerland
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281
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Luna E, Bruce TJ, Roberts MR, Flors V, Ton J. Next-generation systemic acquired resistance. PLANT PHYSIOLOGY 2012; 158:844-53. [PMID: 22147520 PMCID: PMC3271772 DOI: 10.1104/pp.111.187468] [Citation(s) in RCA: 387] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Accepted: 12/05/2011] [Indexed: 05/17/2023]
Abstract
Systemic acquired resistance (SAR) is a plant immune response to pathogen attack. Recent evidence suggests that plant immunity involves regulation by chromatin remodeling and DNA methylation. We investigated whether SAR can be inherited epigenetically following disease pressure by Pseudomonas syringae pv tomato DC3000 (PstDC3000). Compared to progeny from control-treated Arabidopsis (Arabidopsis thaliana; C(1)), progeny from PstDC3000-inoculated Arabidopsis (P(1)) were primed to activate salicylic acid (SA)-inducible defense genes and were more resistant to the (hemi)biotrophic pathogens Hyaloperonospora arabidopsidis and PstDC3000. This transgenerational SAR was sustained over one stress-free generation, indicating an epigenetic basis of the phenomenon. Furthermore, P(1) progeny displayed reduced responsiveness of jasmonic acid (JA)-inducible genes and enhanced susceptibility to the necrotrophic fungus Alternaria brassicicola. This shift in SA- and JA-dependent gene responsiveness was not associated with changes in corresponding hormone levels. Instead, chromatin immunoprecipitation analyses revealed that SA-inducible promoters of PATHOGENESIS-RELATED GENE1, WRKY6, and WRKY53 in P(1) plants are enriched with acetylated histone H3 at lysine 9, a chromatin mark associated with a permissive state of transcription. Conversely, the JA-inducible promoter of PLANT DEFENSIN1.2 showed increased H3 triple methylation at lysine 27, a mark related to repressed gene transcription. P(1) progeny from the defense regulatory mutant non expressor of PR1 (npr1)-1 failed to develop transgenerational defense phenotypes, demonstrating a critical role for NPR1 in expression of transgenerational SAR. Furthermore, the drm1drm2cmt3 mutant that is affected in non-CpG DNA methylation mimicked the transgenerational SAR phenotype. Since PstDC3000 induces DNA hypomethylation in Arabidopsis, our results suggest that transgenerational SAR is transmitted by hypomethylated genes that direct priming of SA-dependent defenses in the following generations.
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282
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Luna E, Bruce TJA, Roberts MR, Flors V, Ton J. Next-generation systemic acquired resistance. PLANT PHYSIOLOGY 2012; 158:844-853. [PMID: 22147520 DOI: 10.1104/pp.111.18746] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Systemic acquired resistance (SAR) is a plant immune response to pathogen attack. Recent evidence suggests that plant immunity involves regulation by chromatin remodeling and DNA methylation. We investigated whether SAR can be inherited epigenetically following disease pressure by Pseudomonas syringae pv tomato DC3000 (PstDC3000). Compared to progeny from control-treated Arabidopsis (Arabidopsis thaliana; C(1)), progeny from PstDC3000-inoculated Arabidopsis (P(1)) were primed to activate salicylic acid (SA)-inducible defense genes and were more resistant to the (hemi)biotrophic pathogens Hyaloperonospora arabidopsidis and PstDC3000. This transgenerational SAR was sustained over one stress-free generation, indicating an epigenetic basis of the phenomenon. Furthermore, P(1) progeny displayed reduced responsiveness of jasmonic acid (JA)-inducible genes and enhanced susceptibility to the necrotrophic fungus Alternaria brassicicola. This shift in SA- and JA-dependent gene responsiveness was not associated with changes in corresponding hormone levels. Instead, chromatin immunoprecipitation analyses revealed that SA-inducible promoters of PATHOGENESIS-RELATED GENE1, WRKY6, and WRKY53 in P(1) plants are enriched with acetylated histone H3 at lysine 9, a chromatin mark associated with a permissive state of transcription. Conversely, the JA-inducible promoter of PLANT DEFENSIN1.2 showed increased H3 triple methylation at lysine 27, a mark related to repressed gene transcription. P(1) progeny from the defense regulatory mutant non expressor of PR1 (npr1)-1 failed to develop transgenerational defense phenotypes, demonstrating a critical role for NPR1 in expression of transgenerational SAR. Furthermore, the drm1drm2cmt3 mutant that is affected in non-CpG DNA methylation mimicked the transgenerational SAR phenotype. Since PstDC3000 induces DNA hypomethylation in Arabidopsis, our results suggest that transgenerational SAR is transmitted by hypomethylated genes that direct priming of SA-dependent defenses in the following generations.
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Affiliation(s)
- Estrella Luna
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom
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283
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Slaughter A, Daniel X, Flors V, Luna E, Hohn B, Mauch-Mani B. Descendants of primed Arabidopsis plants exhibit resistance to biotic stress. PLANT PHYSIOLOGY 2012. [PMID: 22209872 DOI: 10.1104/ppp.111.191593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
An attack of plants by pathogens or treatment with certain resistance-inducing compounds can lead to the establishment of a unique primed state of defense. Primed plants show enhanced defense reactions upon further challenge with biotic or abiotic stress. Here, we report that the primed state in Arabidopsis (Arabidopsis thaliana) is still functional in the next generation without additional treatment. We compared the reactions of Arabidopsis plants that had been either primed with β-amino-butyric acid (BABA) or with an avirulent isolate of the bacteria Pseudomonas syringae pv tomato (PstavrRpt2). The descendants of primed plants showed a faster and higher accumulation of transcripts of defense-related genes in the salicylic acid signaling pathway and enhanced disease resistance upon challenge inoculation with a virulent isolate of P. syringae. In addition, the progeny of primed plants was also more resistant against the oomycete pathogen Hyaloperonospora arabidopsidis. When transgenerationally primed plants were subjected to an additional priming treatment, their descendants displayed an even stronger primed phenotype, suggesting that plants can inherit a sensitization for the priming phenomenon. Interestingly, this primed to be primed phenotype was much reduced in the Arabidopsis β-amino-butyric acid priming mutant ibs1 (induced BABA sterility1). Our results demonstrate that the primed state of plants is transferred to their progeny and confers improved protection from pathogen attack as compared to the descendants of unprimed plants.
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Affiliation(s)
- Ana Slaughter
- Laboratoire de Biologie Moléculaire et Cellulaire, Institut de Biologie, Université de Neuchâtel, 2009 Neuchâtel, Switzerland
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284
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Slaughter A, Daniel X, Flors V, Luna E, Hohn B, Mauch-Mani B. Descendants of primed Arabidopsis plants exhibit resistance to biotic stress. PLANT PHYSIOLOGY 2012; 158:835-43. [PMID: 22209872 PMCID: PMC3271771 DOI: 10.1104/pp.111.191593] [Citation(s) in RCA: 294] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Accepted: 12/22/2011] [Indexed: 05/17/2023]
Abstract
An attack of plants by pathogens or treatment with certain resistance-inducing compounds can lead to the establishment of a unique primed state of defense. Primed plants show enhanced defense reactions upon further challenge with biotic or abiotic stress. Here, we report that the primed state in Arabidopsis (Arabidopsis thaliana) is still functional in the next generation without additional treatment. We compared the reactions of Arabidopsis plants that had been either primed with β-amino-butyric acid (BABA) or with an avirulent isolate of the bacteria Pseudomonas syringae pv tomato (PstavrRpt2). The descendants of primed plants showed a faster and higher accumulation of transcripts of defense-related genes in the salicylic acid signaling pathway and enhanced disease resistance upon challenge inoculation with a virulent isolate of P. syringae. In addition, the progeny of primed plants was also more resistant against the oomycete pathogen Hyaloperonospora arabidopsidis. When transgenerationally primed plants were subjected to an additional priming treatment, their descendants displayed an even stronger primed phenotype, suggesting that plants can inherit a sensitization for the priming phenomenon. Interestingly, this primed to be primed phenotype was much reduced in the Arabidopsis β-amino-butyric acid priming mutant ibs1 (induced BABA sterility1). Our results demonstrate that the primed state of plants is transferred to their progeny and confers improved protection from pathogen attack as compared to the descendants of unprimed plants.
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