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Staiger D, Korneli C, Lummer M, Navarro L. Emerging role for RNA-based regulation in plant immunity. THE NEW PHYTOLOGIST 2013; 197:394-404. [PMID: 23163405 DOI: 10.1111/nph.12022] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2012] [Accepted: 10/02/2012] [Indexed: 05/20/2023]
Abstract
Infection by phytopathogenic bacteria triggers massive changes in plant gene expression, which are thought to be mostly a result of transcriptional reprogramming. However, evidence is accumulating that plants additionally use post-transcriptional regulation of immune-responsive mRNAs as a strategic weapon to shape the defense-related transcriptome. Cellular RNA-binding proteins regulate RNA stability, splicing or mRNA export of immune-response transcripts. In particular, mutants defective in alternative splicing of resistance genes exhibit compromised disease resistance. Furthermore, detection of bacterial pathogens induces the differential expression of small non-coding RNAs including microRNAs that impact the host defense transcriptome. Phytopathogenic bacteria in turn have evolved effector proteins to inhibit biogenesis and/or activity of cellular microRNAs. Whereas RNA silencing has long been known as an antiviral defense response, recent findings also reveal a major role of this process in antibacterial defense. Here we review the function of RNA-binding proteins and small RNA-directed post-transcriptional regulation in antibacterial defense. We mainly focus on studies that used the model system Arabidopsis thaliana and also discuss selected examples from other plants.
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Affiliation(s)
- Dorothee Staiger
- Molecular Cell Physiology, Bielefeld University, D-33615, Bielefeld, Germany
- Institute for Genome Research and Systems Biology, CeBiTec, Bielefeld University, D-33615, Bielefeld, Germany
| | - Christin Korneli
- Molecular Cell Physiology, Bielefeld University, D-33615, Bielefeld, Germany
- Institute for Genome Research and Systems Biology, CeBiTec, Bielefeld University, D-33615, Bielefeld, Germany
| | - Martina Lummer
- Molecular Cell Physiology, Bielefeld University, D-33615, Bielefeld, Germany
- Institute for Genome Research and Systems Biology, CeBiTec, Bielefeld University, D-33615, Bielefeld, Germany
| | - Lionel Navarro
- Institut de Biologie de L'Ecole Normale Supérieure (IBENS), 46 Rue d'Ulm, 75230, Paris Cedex 05, France
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2
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Woloshen V, Huang S, Li X. RNA-Binding Proteins in Plant Immunity. J Pathog 2011; 2011:278697. [PMID: 22567326 PMCID: PMC3335643 DOI: 10.4061/2011/278697] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 05/17/2011] [Accepted: 06/03/2011] [Indexed: 11/24/2022] Open
Abstract
Plant defence responses against pathogen infection are crucial to plant survival. The high degree of regulation of plant immunity occurs both transcriptionally and posttranscriptionally. Once transcribed, target gene RNA must be processed prior to translation. This includes polyadenylation, 5′capping, editing, splicing, and mRNA export. RNA-binding proteins (RBPs) have been implicated at each level of RNA processing. Previous research has primarily focused on structural RNA-binding proteins of yeast and mammals; however, more recent work has characterized a number of plant RBPs and revealed their roles in plant immune responses. This paper provides an update on the known functions of RBPs in plant immune response regulation. Future in-depth analysis of RBPs and other related players will unveil the sophisticated regulatory mechanisms of RNA processing during plant immune responses.
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Affiliation(s)
- Virginia Woloshen
- Michael Smith Laboratories, University of British Columbia, Vancouver, Canada V6T 1Z4
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3
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Bozkurt TO, McGrann GRD, MacCormack R, Boyd LA, Akkaya MS. Cellular and transcriptional responses of wheat during compatible and incompatible race-specific interactions with Puccinia striiformis f. sp. tritici. MOLECULAR PLANT PATHOLOGY 2010; 11:625-40. [PMID: 20696001 PMCID: PMC6640440 DOI: 10.1111/j.1364-3703.2010.00633.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The initial stages of Puccinia striiformis f. sp. tritici (the causal agent of yellow rust in wheat) infection triggered a hypersensitive cell death (HCD) response in both compatible and Yr1-mediated incompatible interactions, although the response was earlier and more extensive in the incompatible interaction. Later stages of fungal development were only associated with an HCD response in the incompatible interaction, the HCD response being effectively suppressed in the compatible interaction. Cell autofluorescence was seen in mesophyll cells in direct contact with fungal infection hyphae (primary HCD) and in adjacent mesophyll cells (secondary HCD), indicating the activation of cell-to-cell signalling. Microarray analysis identified a number of defence-related transcripts implicated in Yr1-mediated resistance, including classical pathogenesis-related (PR) transcripts and genes involved in plant cell defence responses, such as the oxidative burst and cell wall fortification. A quantitative reverse transcriptase-polymerase chain reaction time course analysis identified a number of defence-related genes, including PR2, PR4, PR9, PR10 and WIR1 transcripts, associated with the latter stages of Yr1-mediated resistance. A meta-analysis comparison of the Yr1-regulated transcriptome with the resistance transcriptomes of the race-specific resistance gene Yr5 and the race-nonspecific adult plant resistance gene Yr39 indicated limited transcript commonality. Common transcripts were largely confined to classic PR and defence-related genes.
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Affiliation(s)
- Tolga O Bozkurt
- Middle East Technical University, Department of Chemistry, Biochemistry and Biotechnology Programs, Ankara, Turkey
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4
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Liu C, Mehdy MC. A nonclassical arabinogalactan protein gene highly expressed in vascular tissues, AGP31, is transcriptionally repressed by methyl jasmonic acid in Arabidopsis. PLANT PHYSIOLOGY 2007; 145:863-74. [PMID: 17885091 PMCID: PMC2048811 DOI: 10.1104/pp.107.102657] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2007] [Accepted: 09/10/2007] [Indexed: 05/17/2023]
Abstract
In response to wounding and pathogens, jasmonate (JA) serves as a signal molecule for both induction and repression of gene expression. To examine defense-regulated gene repression in Arabidopsis (Arabidopsis thaliana), we have identified a nonclassical arabinogalactan protein (AGP) gene, AGP31, and show that its mRNA decreased to about 30% of its original level within 8 h in response to methyl JA (MeJA) treatment of whole 7-d-old seedlings. Wounding and abscisic acid treatment had similar effects. MeJA suppression primarily depends on the action of the JA-signaling protein, COI1, as shown by much lower MeJA suppression in coi1-1 mutant plants. The main mechanism of mRNA suppression by MeJA is repression of transcription, as shown by nuclear run-on experiments. The AGP31 protein shares features with several known and putative nonclassical AGPs from other species: a putative signal peptide, a histidine-rich region near the N terminus followed by a repetitive proline-rich domain, and a cysteine-rich C-terminal PAC (for proline-rich protein and AGP, containing cysteine) domain. Positive Yariv reagent interaction demonstrated that the protein is an AGP. Monosaccharide analysis of purified AGP31 indicated it is a galactose-rich AGP. Expression of an AGP31-enhanced green fluorescent protein fusion protein in transgenic cells revealed that the AGP31 protein was localized to the cell wall. AGP31 promoter-beta-glucuronidase reporter gene analysis showed expression in the vascular bundle throughout the plant, except in the flower. In the flower, beta-glucuronidase staining occurred throughout the pistil, except in the stigma. The strong preferential expression in vascular tissues suggests that AGP31 may be involved in vascular tissue function during both the defense response and development.
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Affiliation(s)
- Chenggang Liu
- Section of Molecular, Cell, and Developmental Biology, University of Texas, Austin, Texas 78712, USA
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5
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Yakir E, Hilman D, Hassidim M, Green RM. CIRCADIAN CLOCK ASSOCIATED1 transcript stability and the entrainment of the circadian clock in Arabidopsis. PLANT PHYSIOLOGY 2007; 145:925-32. [PMID: 17873091 PMCID: PMC2048808 DOI: 10.1104/pp.107.103812] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The circadian clock is an endogenous mechanism that generates rhythms with an approximately 24-h period and enables plants to predict and adapt to daily and seasonal changes in their environment. These rhythms are generated by molecular oscillators that in Arabidopsis (Arabidopsis thaliana) have been shown to consist of interlocking feedback loops involving a number of elements. An important characteristic of circadian oscillators is that they can be entrained by daily environmental changes in light and temperature. Previous work has shown that one possible entrainment point for the Arabidopsis oscillator is the light-mediated regulation of expression of one of the oscillator genes, CIRCADIAN CLOCK ASSOCIATED1 (CCA1). In this article, we have used transgenic plants with constitutive CCA1 expression to show that light also regulates CCA1 transcript stability. Our experiments show that CCA1 messenger RNA is relatively stable in the dark and in far-red light but has a short half-life in red and blue light. Furthermore, using transgenic plants expressing chimeric CCA1 constructs, we demonstrate that the instability determinants in CCA1 transcripts are probably located in the coding region. We suggest that the combination of light regulation of CCA1 transcription and CCA1 messenger RNA degradation is important for ensuring that the Arabidopsis circadian oscillator is accurately entrained by environmental changes.
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Affiliation(s)
- Esther Yakir
- Department of Plant and Environmental Sciences, Institute for Life Sciences, Hebrew University, Givat Ram, Jerusalem 91904, Israel
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6
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Suzuki K, Nishiuchi T, Nakayama Y, Ito M, Shinshi H. Elicitor-induced down-regulation of cell cycle-related genes in tobacco cells. PLANT, CELL & ENVIRONMENT 2006; 29:183-91. [PMID: 17080634 DOI: 10.1111/j.1365-3040.2005.01411.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The fungal elicitors, a xylanase from Trichoderma viride and an extract from the cell wall of Phytophthora infestans, are shown to cause a rapid reduction of the mRNA levels of various cell cycle-related genes, including MAP kinase genes and cyclin genes, in cultured tobacco cells (Nicotiana tabacum cv. Xanthi, line XD6S). Pharmacological analyses suggest that the elicitor-induced decrease in Bi-type cyclin (Nicta;CycB1;3) and A1-type cyclin (Nicta;CycA1;1) mRNAs may be due to transcriptional repression, and that in D3-type cyclin (Nicta;CycD3;2) mRNA due to destabilization of the mRNA molecule itself. The activity of protein kinases is required for both the activation of defence genes and the repression of cyclin genes. The transcriptional activity of the promoter of the B1-class cyclin gene decreases upon elicitor treatment. The transactivation activity of NtmybA2, a tobacco Myb transcription activator for the M phase-specific cis-acting elements in the promoter of the B-type cyclin gene, is inhibited by elicitor treatment. In addition, the mRNA levels of NtmybA2 and two other related genes, NtmybA1 and NtmybB, decrease in response to the elicitor. Finally, we discuss a negative cross-talk between signal transduction pathways for growth and defence responses, which might be important for adaptation to environmental stress by potential pathogens.
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Affiliation(s)
- Kaoru Suzuki
- Molecular and Cellular Breeding Research Group, Institute for Biological Resources and Functions, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 6, 1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan.
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7
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Ebel C, Gómez LG, Schmit AC, Neuhaus-Url G, Boller T. Differential mRNA degradation of two beta-tubulin isoforms correlates with cytosolic Ca2+ changes in glucan-elicited soybean cells. PLANT PHYSIOLOGY 2001; 126:87-96. [PMID: 11351073 PMCID: PMC102284 DOI: 10.1104/pp.126.1.87] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2001] [Accepted: 01/18/2001] [Indexed: 05/23/2023]
Abstract
Transgenic soybean (Glycine max) culture cells expressing apoaequorin, a Ca2+ indicator, were exposed to glucan fragments derived from Phytophthora sojae or to chitin oligomers. The effects of these elicitors on cytosolic Ca2+ concentrations and on mRNA levels of two beta-tubulin isoforms, tubB1 and tubB2, were investigated. The glucan elicitors, to which the cells are known to react with a biphasic cytosolic Ca2+ increase, induced a down-regulation of the tubB1 mRNA levels while the tubB2 mRNA level remained constant. The decrease of tubB1 mRNA level was observed after 1 hour of glucan treatment. In contrast, chitin oligomers, known to provoke a monophasic Ca2+ increase of short duration, did not affect the tubB1 mRNA level. Pre-incubation with 10 mM 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid, an extracellular Ca2+ chelator, blocked the cytosolic Ca2+ increase as well as the decrease of tubB1 mRNA levels induced by glucan elicitors. Likewise, pre-incubation with 1 mM neomycin, which reduced only the second glucan-induced Ca2+ peak, blocked the decrease of tubB1 mRNA level. Experiments with cordycepin, a transcription inhibitor, indicated that glucan fragments induced the degradation of tubB1 mRNA. In conclusion, the glucan-induced cytosolic Ca2+ changes are correlated with a strong increase in tubB1 mRNA degradation.
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Affiliation(s)
- C Ebel
- Friedrich Miescher-Institut, P.O. Box 2543, CH-4002 Basel, Switzerland.
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8
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Ortega JL, Temple SJ, Sengupta-Gopalan C. Constitutive overexpression of cytosolic glutamine synthetase (GS1) gene in transgenic alfalfa demonstrates that GS1 may be regulated at the level of RNA stability and protein turnover. PLANT PHYSIOLOGY 2001; 126:109-21. [PMID: 11351075 PMCID: PMC102286 DOI: 10.1104/pp.126.1.109] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2000] [Revised: 01/08/2001] [Accepted: 01/30/2001] [Indexed: 05/18/2023]
Abstract
Glutamine synthetase (GS) catalyzes the ATP-dependent condensation of NH4+ with glutanate to yield glutamine. Gene constructs consisting of the cauliflower mosaic virus (CaMV) 35S promoter driving a cytosolic isoform of GS (GS1) gene have been introduced into alfalfa (Medicago sativa). Although transcripts for the transgene were shown to accumulate to high levels in the leaves, they were undetectable in the nodules. However, significant amounts of beta-glucuronidase activity could be detected in nodules of plants containing the CaMV 35S promoter-beta-glucuronidase gene construct, suggesting that the transcript for the GS1 transgene is not stable in the root nodules. Leaves of alfalfa plants with the CaMV 35S promoter-GS1 gene showed high levels of accumulation of the transcript for the transgene when grown under low-nitrogen conditions and showed a significant drop in the level of GS1 transcripts when fed with high levels of NO3-. However, no increase in GS activity or polypeptide level was detected in the leaves of transgenic plants. The results suggest that GS1 is regulated at the level of RNA stability and protein turnover.
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Affiliation(s)
- J L Ortega
- Agronomy and Horticulture Department, New Mexico State University, Las Cruces, New Mexico 88003, USA
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9
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Johnson MA, Perez-Amador MA, Lidder P, Green PJ. Mutants of Arabidopsis defective in a sequence-specific mRNA degradation pathway. Proc Natl Acad Sci U S A 2000; 97:13991-6. [PMID: 11087822 PMCID: PMC17688 DOI: 10.1073/pnas.240354097] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
One of the ways a cell can rapidly and tightly regulate gene expression is to target specific mRNAs for rapid decay. A number of mRNA instability sequences that mediate rapid mRNA decay have been identified, particularly from multicellular eukaryotes, but pinpointing the cellular components that play critical roles in sequence-specific decay in vivo has been more difficult. In contrast, general pathways of mRNA degradation in yeast have been well established through the analysis of mutants affecting the general mRNA decay machinery. Strategies to isolate mutants in sequence-specific mRNA decay pathways, although extremely limited so far, have the potential to be just as powerful. In the study reported here, a selection in transgenic plants allowed the isolation of rare mutants of Arabidopsis thaliana that elevate the abundance of mRNAs that contain the plant mRNA instability sequence called DST (downstream element). This instability sequence is highly conserved in unstable small auxin up RNA (SAUR) transcripts. Genetic analysis of two dst mutants isolated via this selection showed that they are incompletely dominant and represent two independent loci. In addition to affecting DST-containing transgene mRNAs, mutations at both loci increased the abundance of the endogenous DST-containing SAUR-AC1 mRNA, but not controls lacking DST sequences. That these phenotypes are caused by deficiencies in DST-mediated mRNA decay was supported by mRNA stability measurements in transgenic plants. Isolation of the dst mutants provides a means to study sequence-specific mRNA degradation in vivo and establishes a method to isolate similar mutants from other organisms.
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Affiliation(s)
- M A Johnson
- Department of Energy Plant Research Laboratory, Program in Cellular and Molecular Biology, and Department of Biochemistry, Michigan State University, Plant Biology Building, East Lansing, MI 48824-1312, USA
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10
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Lapopin L, Gianinazzi-Pearson V, Franken P. Comparative differential RNA display analysis of arbuscular mycorrhiza in Pisum sativum wild type and a mutant defective in late stage development. PLANT MOLECULAR BIOLOGY 1999; 41:669-77. [PMID: 10645726 DOI: 10.1023/a:1006387523343] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In order to analyse gene expression associated with the late stages of arbuscular mycorrhizal development between Pisum sativum and Glomus mosseae, comparative differential RNA display was carried out using wild-type P. sativum and a mutant, RisNod24, where the fungal partner is not able to form functional arbuscules. Comparison of RNA accumulation patterns between controls, G. mosseae-colonized mutant and wild-type roots resulted in the identification of four differentially occurring cDNA fragments. One of the corresponding genes was from the fungus and three of plant origin. One plant gene, Psam4 (P. sativum arbuscular mycorrhiza-regulated), was analysed in more detail. Sequencing of a cDNA clone showed that Psam4 encodes a proline-rich protein. Northern blot analysis and quantitative RT-PCR revealed a higher basal level of Psam4 RNA accumulation in the mutant compared to the wild type. In both pea genotypes, RNA accumulation was reduced after inoculation with mycorrhiza- or nodule-forming symbiotic microorganisms, but enhanced after infection with a root pathogenic fungus.
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MESH Headings
- Base Sequence
- Blotting, Northern
- Blotting, Southern
- Cloning, Molecular
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- DNA, Fungal/analysis
- DNA, Plant/analysis
- Fungi/genetics
- Fungi/growth & development
- Gene Expression Regulation, Fungal
- Gene Expression Regulation, Plant
- Molecular Sequence Data
- Mutation
- Pisum sativum/genetics
- Pisum sativum/growth & development
- Pisum sativum/microbiology
- Plant Proteins/genetics
- Plant Roots/genetics
- RNA, Fungal/genetics
- RNA, Fungal/isolation & purification
- RNA, Fungal/metabolism
- RNA, Plant/genetics
- RNA, Plant/isolation & purification
- RNA, Plant/metabolism
- Sequence Analysis, DNA
- Symbiosis/genetics
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Affiliation(s)
- L Lapopin
- Max-Planck-Institut für terrestrische Mikrobiologie, and Laboratorium für Mikrobiologie des Fachbereichs Biologie der Philipps-Universität, Marburg, Germany
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11
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Harrak H, Chamberland H, Plante M, Bellemare G, Lafontaine JG, Tabaeizadeh Z. A proline-, threonine-, and glycine-rich protein down-regulated by drought is localized in the cell wall of xylem elements. PLANT PHYSIOLOGY 1999; 121:557-64. [PMID: 10517847 PMCID: PMC59418 DOI: 10.1104/pp.121.2.557] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
A cDNA clone encoding a proline-, threonine-, and glycine-rich protein (PTGRP) was isolated from a wild tomato species (Lycopersicon chilense) (L.X. Yu, H. Chamberland, J.G. Lafontain, Z. Tabaeizadeh [1996] Genome 39: 1185-1193). Northern-blot analysis and in situ hybridization studies revealed that PTGRP is down-regulated by drought stress. The level of the mRNA in leaves and stems of 8-d drought-stressed plants decreased 5- to 10-fold compared with that in regularly watered plants. The mRNA re-accumulated when drought-stressed plants were rewatered. Antibodies raised against a glutathione S-transferase/PTGRP fusion protein were used to elucidate the subcellular localization of the protein by immunogold labeling. In regularly watered L. chilense plants, PTGRP protein was found to be localized in xylem pit membranes and disintegrated primary walls. Examination of sections from drought-stressed plants revealed a significant decrease in the levels of labeling. In these samples, only a few scattered gold particles were detected in the same areas. In the leaf tissues of plants that had been rewatered for 3 d following an 8-d drought stress, the labeling pattern was similar to that of the regularly watered plants. To our knowledge, PTGRP is the first drought-regulated protein that has been precisely localized in the cell wall.
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Affiliation(s)
- H Harrak
- Department of Biological Sciences, University of Quebec, P.O. Box 8888, Station Centre Ville, Montreal, Quebec, Canada H3C 3P8
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12
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Johnson RR, Chaverra ME, Cranston HJ, Pleban T, Dyer WE. Degradation of oat mRNAs during seed development. PLANT MOLECULAR BIOLOGY 1999; 39:823-833. [PMID: 10350095 DOI: 10.1023/a:1006179315016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The genes AV1, AV10, and Z1 encode proteins that accumulate during oat seed development. In developing endosperm of Avena sativa (cultivated oat), AV1, AV10 and Z1 mRNAs reach maximal levels midway through seed development but fall to very low levels in mature seeds. Similarly, mRNAs for these proteins peak during endosperm development of Avena fatua (wild oat) and are later degraded. However, during late maturation of A. fatua seeds, populations of mRNA fragments shorter than the intact transcripts accumulate as the full-length transcripts decline in abundance. The smaller RNA molecules, which are apparently long-lived decay intermediates, are derived randomly from the entire transcripts and are most likely not generated by cleavage at precisely defined sites. Other A. fatua endosperm mRNAs that are degraded during late seed development, such as those for ADP glucose pyrophosphorylase and starch synthase, do not produce detectable decay intermediates. Decay intermediates of AV1 and Z1 mRNAs persist at high levels during late seed development of two other undomesticated oat species, Avena strigosa and Avena barbata. The persistence of decay intermediates for these endosperm mRNAs in wild grass species may represent a model system for studying RNA decay process in plant tissues.
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Affiliation(s)
- R R Johnson
- Department of Biology, Colby College, Waterville, ME 04901-8857, USA
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13
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Petracek ME, Dickey LF, Nguyen TT, Gatz C, Sowinski DA, Allen GC, Thompson WF. Ferredoxin-1 mRNA is destabilized by changes in photosynthetic electron transport. Proc Natl Acad Sci U S A 1998; 95:9009-13. [PMID: 9671795 PMCID: PMC21193 DOI: 10.1073/pnas.95.15.9009] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/1998] [Indexed: 02/08/2023] Open
Abstract
In transgenic tobacco, pea Ferredoxin-1 (Fed-1) mRNA accumulates rapidly in response to photosynthesis even when the transgene is driven by a constitutive promoter. To investigate the role of photosynthesis on Fed-1 mRNA stability, we used the tetracycline repressible Top10 promoter system to specifically shut off transcription of the Fed-1 transgene. The Fed-1 mRNA has a half-life of approximately 2.4 hr in the light and a half-life of only 1.2 hr in the dark or in the presence of the photosynthetic electron transport inhibitor 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU). These data indicate that cessation of photosynthesis, either by darkness or DCMU results in a destabilization of the Fed-1 mRNA. Furthermore, the Fed-1 mRNA half-life is reduced immediately upon transfer to darkness, suggesting that Fed-1 mRNA destabilization is a primary response to photosynthesis rather than a secondary response to long-term dark adaptation. Finally, the two different methods for efficient tetracycline delivery reported here generally should be useful for half-life measurements of other mRNAs in whole plants.
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Affiliation(s)
- M E Petracek
- Department of Botany, North Carolina State University, Raleigh, NC 27695, USA.
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14
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Zhang S, Klessig DF. The tobacco wounding-activated mitogen-activated protein kinase is encoded by SIPK. Proc Natl Acad Sci U S A 1998; 95:7225-30. [PMID: 9618567 PMCID: PMC22786 DOI: 10.1073/pnas.95.12.7225] [Citation(s) in RCA: 166] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
It has been demonstrated that both salicylic acid and fungal elicitors activate a 48-kDa mitogen-activated protein kinase termed salicylic acid-induced protein kinase (SIPK) in tobacco suspension cells. Here, we show that infiltration of these agents into tobacco leaves also activates SIPK. Of particular interest, infiltration of water alone activated a kinase of the same size, possibly because of wounding and/or osmotic stresses. The kinetics of kinase activation, however, differ for these different treatments. Various mechanical stresses, including cutting and wounding by abrasion, also activated a 48-kDa kinase. By using an immune-complex kinase assay with antibodies specific for SIPK or wounding-induced protein kinase, we demonstrate that this wounding-activated 48-kDa kinase is SIPK, rather than wounding-induced protein kinase, as reported [Seo, S., Okamoto, M., Seto, H., Ishizuka, K., Sano, H. & Ohashi, Y. (1995) Science 270, 1988-1992]. Activation of SIPK after wounding was associated with tyrosine phosphorylation but not with increases in SIPK mRNA or protein levels. Thus, the same mitogen-activated protein kinase, SIPK, appears to facilitate signaling for two distinct pathways that lead to disease resistance responses and wounding responses.
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Affiliation(s)
- S Zhang
- Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers, State University of New Jersey, Piscataway, NJ 08854-8020, USA
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15
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Zhang S, Du H, Klessig DF. Activation of the tobacco SIP kinase by both a cell wall-derived carbohydrate elicitor and purified proteinaceous elicitins from Phytophthora spp. THE PLANT CELL 1998. [PMID: 9501116 DOI: 10.2307/3870600] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Two purified proteinaceous fungal elicitors, parasiticein (an alpha elicitin) and cryptogein (a beta elicitin), as well as a fungal cell wall-derived carbohydrate elicitor all rapidly activated a 48-kD kinase in tobacco suspension cells. The maximum activation of this kinase paralleled or preceded medium alkalization and activation of the defense gene phenylalanine ammonia-lyase (PAL). In addition, the two elicitins, which also induced hypersensitive cell death, activated a 44- and a 40-kD kinase with delayed kinetics. By contrast, the cell wall-derived elicitor only weakly activated the 44-kD kinase and failed to activate the 40-kD kinase. The size and substrate preference of the 48-kD kinase are reminiscent of the recently purified and cloned salicylic acid-induced protein (SIP) kinase, which is a member of the mitogen-activated protein kinase family. Antibodies raised against a peptide corresponding to the unique N terminus of SIP kinase immunoreacted with the 48-kD kinase activated by all three elicitors from Phytophthora spp. In addition, the cell wall elicitor and the salicylic acid-activated 48-kD kinase copurified through several chromatography steps and comigrated on two-dimensional gels. Based on these results, all three fungal elicitors appear to activate the SIP kinase. In addition, inhibition of SIP kinase activation by kinase inhibitors correlated with the suppression of cell wall elicitor-induced medium alkalization and PAL gene activation, suggesting a regulatory function for the SIP kinase in these defense responses.
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Affiliation(s)
- S Zhang
- Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, 190 Frelinghuysen Road, Piscataway, New Jersey 08854-8020, USA
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16
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Zhang S, Du H, Klessig DF. Activation of the tobacco SIP kinase by both a cell wall-derived carbohydrate elicitor and purified proteinaceous elicitins from Phytophthora spp. THE PLANT CELL 1998; 10:435-50. [PMID: 9501116 PMCID: PMC144006 DOI: 10.1105/tpc.10.3.435] [Citation(s) in RCA: 125] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Two purified proteinaceous fungal elicitors, parasiticein (an alpha elicitin) and cryptogein (a beta elicitin), as well as a fungal cell wall-derived carbohydrate elicitor all rapidly activated a 48-kD kinase in tobacco suspension cells. The maximum activation of this kinase paralleled or preceded medium alkalization and activation of the defense gene phenylalanine ammonia-lyase (PAL). In addition, the two elicitins, which also induced hypersensitive cell death, activated a 44- and a 40-kD kinase with delayed kinetics. By contrast, the cell wall-derived elicitor only weakly activated the 44-kD kinase and failed to activate the 40-kD kinase. The size and substrate preference of the 48-kD kinase are reminiscent of the recently purified and cloned salicylic acid-induced protein (SIP) kinase, which is a member of the mitogen-activated protein kinase family. Antibodies raised against a peptide corresponding to the unique N terminus of SIP kinase immunoreacted with the 48-kD kinase activated by all three elicitors from Phytophthora spp. In addition, the cell wall elicitor and the salicylic acid-activated 48-kD kinase copurified through several chromatography steps and comigrated on two-dimensional gels. Based on these results, all three fungal elicitors appear to activate the SIP kinase. In addition, inhibition of SIP kinase activation by kinase inhibitors correlated with the suppression of cell wall elicitor-induced medium alkalization and PAL gene activation, suggesting a regulatory function for the SIP kinase in these defense responses.
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Affiliation(s)
- S Zhang
- Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, 190 Frelinghuysen Road, Piscataway, New Jersey 08854-8020, USA
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17
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Cerutti H, Johnson AM, Gillham NW, Boynton JE. A eubacterial gene conferring spectinomycin resistance on Chlamydomonas reinhardtii: integration into the nuclear genome and gene expression. Genetics 1997; 145:97-110. [PMID: 9017393 PMCID: PMC1207788 DOI: 10.1093/genetics/145.1.97] [Citation(s) in RCA: 99] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
We have constructed a dominant selectable marker for nuclear transformation of C. reinhardtii, composed of the coding sequence of the eubacterial aadA gene (conferring spectinomycin resistance) fused to the 5' and 3' untranslated regions of the endogenous RbcS2 gene. Spectinomycin-resistant transformants isolated by direct selection (1) contain the chimeric gene(s) stably integrated into the nuclear genome, (2) show cosegregation of the resistance phenotype with the introduced DNA, and (3) synthesize the expected mRNA and protein. Small linearized plasmids appeared to be inserted into the nuclear genome preferentially through their ends, with relatively few large deletions and/or rearrangements. Multiple copy transformants often integrated concatemers of transforming DNA. Our detailed analysis of the complex integration patterns of plasmid DNA in C. reinhardtii nuclear transformants should be useful for improving the technique of insertional mutagenesis. We also found that the spectinomycin-resistance phenotype was unstable in about half of the transformants. When maintained under nonselective conditions, neither the aadA mRNA nor the AadA protein were detected in these subclones. Moreover, since the integrated transforming DNA was not altered or lost expression of the RbcS2::aadA::RbcS2 gene(s) appears to be repressed. Measurements of transcriptional activity, mRNA accumulation, and mRNA stability suggest that expression of this chimeric gene(s) may also be affected by rapid RNA degradation, presumably due to defects in mRNA processing and, or nuclear export. Thus, both gene silencing and transcript instability, rather than biased codon usage, may explain the difficulties encountered in the expression of foreign genes in the nuclear genome of Chlamydomonas.
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Affiliation(s)
- H Cerutti
- Department of Botany, Duke University, Durham, North Carolina 27708, USA
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18
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Peng HM, Dreyer DA, VandenBosch KA, Cook D. Gene structure and differential regulation of the Rhizobium-induced peroxidase gene rip1. PLANT PHYSIOLOGY 1996; 112:1437-46. [PMID: 8972593 PMCID: PMC158075 DOI: 10.1104/pp.112.4.1437] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Primary expression of the Rhizobium meliloti-induced peroxidase gene rip1 occurs prior to nodule morphogenesis, specifically at the site of impending rhizobial infection (D. Cook, D. Dreyer, D. Bonnet, M. Howell, E. Nony, K. VandenBosch [1995] Plant Cell 7: 43-55). We examined the distribution and structure of rip1 transcript throughout nodule development. We determined that expression of rip1 in root tips is correlated with the competence of this zone for symbiotic association, whereas after rhizobial infection rip1 transcript is specifically associated with the zone of nodule development, including nascent nodule primordia. rip1 transcripts are characterized by multiple polyadenylation sites distributed within 200 to 400 bp of the translation stop site, and a single major transcription initiation site in close proximity to the rip1 open reading frame. Thus, rip1 expression is likely to be mediated through effects on a single transcription unit. Immediately 5' of the rip1 transcription unit DNA sequence analysis identified a 377-bp DNA element containing extensive repeat structure that is widely distributed in the Medicago truncatula genome.
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Affiliation(s)
- H M Peng
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station 77843, USA
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19
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Abstract
The degradation rates of different mRNAs in higher plants can vary over a broad range and are regulated by a variety of endogenous and exogenous stimuli. During the past several years, efforts to better understand the control of mRNA stability in plants have increased considerably and this has led to improved methodologies and important mechanistic insights. In this review, we highlight some of the most interesting examples of plant transcripts that are controlled at the level of mRNA decay and discuss what has been learned from their study. Experiments that implicate or demonstrate the involvement of particular cis- and trans-acting factors in mRNA decay pathways are a major focus, as are those experiments that have led to mechanistic models. Emphasis is also placed on studies that address the relationship between translation and mRNA stability. Our current knowledge indicates that some of the determinants and pathways for mRNA decay may differ in plants compared to other eukaryotes, whereas others appear to be similar. This knowledge, coupled with the availability of biochemical, molecular and genetic approaches to elucidate plant mRNA decay mechanisms, should continue to lead to findings of novel and general significance.
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Affiliation(s)
- M L Abler
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing 48824-1312, USA
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20
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Ni W, Sewalt VJH, Korth KL, Blount JW, Ballance GM, Dixon RA. Stress Responses in Alfalfa (XXI. Activation of Caffeic Acid 3-O-Methyltransferase and Caffeoyl Coenzyme A 3-O-Methyltransferase Genes Does Not Contribute to Changes in Metabolite Accumulation in Elicitor-Treated Cell-Suspension Cultures). PLANT PHYSIOLOGY 1996; 112:717-726. [PMID: 12226420 PMCID: PMC157996 DOI: 10.1104/pp.112.2.717] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Transcription of genes encoding L-phenylalanine ammonia-lyase (PAL), the first enzyme of the phenylpropanoid pathway, and caffeic acid 3-O-methyltransferase (COMT) and caffeoyl CoA 3-O-methyltransferase (CCOMT), enzymes involved in the synthesis of lignin and wall-esterified phenolic compounds, was strongly activated in elicitor-treated cell-suspension cultures of alfalfa (Medicago sativa L.). However, consequent changes in the extractable activities of COMT and CCOMT were small to nonexistent compared with a 15- to 16-fold increase in PAL activity. Only low levels of COMT and CCOMT transcripts were reflected in the total and polysomal RNA fractions compared with PAL transcripts. Elicited cell cultures did not accumulate lignin or the products of COMT and CCOMT in the soluble and wall-esterified phenolic fractions. In one alfalfa cell line in which elicitation resulted in very high PAL activity and increased deposition of methoxyl groups in the insoluble wall fraction, there was still no change in COMT and CCOMT activities. Overall, these results indicate that the initial gene transcription events in elicited cells may be less selective than the subsequent metabolic changes, highlighting the importance of posttranscriptional events in the control of phenylpropanoid biosynthesis.
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Affiliation(s)
- W. Ni
- Plant Biology Division, Samuel Roberts Noble Foundation, P.O. Box 2180, Ardmore, Oklahoma 73402
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21
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Silver DL, Pinaev A, Chen R, De Bruijn FJ. Posttranscriptional Regulation of the Sesbania rostrata Early Nodulin Gene SrEnod2 by Cytokinin. PLANT PHYSIOLOGY 1996; 112:559-567. [PMID: 12226409 PMCID: PMC157978 DOI: 10.1104/pp.112.2.559] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The mRNA from the Sesbania rostrata early nodulin gene SrEnod2 accumulates in response to cytokinin application. Nuclear run-on assays using isolated root nuclei have shown that this accumulation occurs posttranscriptionally, and northern blot analysis of nuclear and total RNA levels revealed that it occurs primarily in the cytoplasm and not in the nucleus. After cytokinin enhancement of SrEnod2 mRNA accumulation and the subsequent removal of cytokinin, the levels of SrEnod2 mRNA did not return to basal levels, but oscillated over a 36-h time course. Application of the translational inhibitor cycloheximide was found to inhibit the enhancement of SrEnod2 mRNA accumulation by cytokinin and to cause its rapid decay. Okadaic acid and staurosporine, inhibitors of protein phosphatases and kinases, respectively, also inhibited cytokinin enhancement of SrEnod2 mRNA accumulation. In addition, okadaic acid was found to cause a decrease in SrEnod2 mRNA levels. These results provide evidence for a posttranscriptional mechanism of cytokinin enhancement of SrEnod2 mRNA accumulation, which appears to require concurrent protein synthesis, to involve protein phosphatases and kinases, and to occur primarily in the cytoplasm of the plant cell.
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Affiliation(s)
- D. L. Silver
- Michigan State University-Department of Energy Plant Research Laboratory (D.L.S., A.P., R.C., F.J.d.B.), Genetics Program (D.L.S., F.J.d.B.), Department of Biochemistry (R.C.), and Department of Microbiology (F.J.d.B.), Michigan State University, East Lansing, Michigan 48824
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22
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Walter MH, Liu JW, Wünn J, Hess D. Bean ribonuclease-like pathogenesis-related protein genes (Ypr10) display complex patterns of developmental, dark-induced and exogenous-stimulus-dependent expression. EUROPEAN JOURNAL OF BIOCHEMISTRY 1996; 239:281-93. [PMID: 8706731 DOI: 10.1111/j.1432-1033.1996.0281u.x] [Citation(s) in RCA: 102] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The intracellular pathogenesis-related (PR) proteins of common bean (Phaseolus vulgaris L.) are encoded by a highly polymorphic family of at least 20 genes. One member, the Ypr10*c gene, has been isolated and characterised. The deduced amino acid sequence of the encoded protein, PR-10, exhibits similarities to tree-pollen allergens, to food allergens from celery and apple and to ginseng ribonuclease peptide sequences. We show by RNA blot analysis that the Ypr10 gene family, including Ypr10*c, is strongly expressed in bean roots. In leaves Ypr10 transcript levels are low in young and mature stages but are elevated during senescence and in diseased states. Dark treatment of leaves causes strong induction of Ypr10 transcripts, which is reversible by light, and diurnal rhythms of transcript accumulation during the night are observed. Ypr10 genes are responsive to external stimuli related to pathogen-defence such as glutathione or salicylic acid. Transcriptional activity of a Ypr10*c promoter-beta-glucuronidase fusion gene in transgenic tobacco was observed in roots, in developing xylem and phloem of stems, and in the blade of senescent leaves, with highest levels at the onset of senescence. The most striking characteristic of developmental expression was the specific localisation of beta-glucuronidase activity in the transmitting tract of styles in flowers at anthesis. Feeding of various pathogen-related and stress-related stimuli to young tobacco leaves led to accumulation of GUS activity in leaf blades. We identify considerable spatio-temporal similarities between reported expression patterns of Ypr10 genes and ribonuclease genes, which, together with the significant sequence similarity to the ginseng ribonuclease, support the hypothesis of a ribonuclease function for PR-10 proteins and allow the prediction of possible biological roles.
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Affiliation(s)
- M H Walter
- Universität Hohenheim, Institut für Pflanzenphysiologie, Stuttgart, Germany
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23
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Sharma P, Lönneborg A. Isolation and characterization of a cDNA encoding a plant defensin-like protein from roots of Norway spruce. PLANT MOLECULAR BIOLOGY 1996; 31:707-12. [PMID: 8790304 DOI: 10.1007/bf00042244] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
We are studying the interaction between the roots of Norway spruce seedlings (Picea abies L. Karst) and a highly pathogenic isolate of Pythium dimorphum. Here, we report the isolation of a cDNA from spruce roots encoding a protein with high sequence similarity to plant defensins, designated as SPI1 (Spruce Pathogen Induced No.1). The transcript hybridizing to the SPII cDNA probe is highly induced in uninfected roots when the seedlings are transferred from solid to liquid incubating malt medium (hypoxic conditions). However, when the seedlings are transferred from solid to liquid malt media containing a saturating amount of P. dimorphum hyphae, the amount of transcript is unchanged the first day after infection, but then decreases on day 1, and is no longer detectable 2 days after infection. Since plant defensins may play a role in plant defence, their negative regulation upon infection might reflect a strategy employed by this pathogenic fungus to evade the effect of toxic gene products.
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Affiliation(s)
- P Sharma
- Norwegian Forest Research Institute, As, Norway
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24
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Li B, Foley ME. Transcriptional and Posttranscriptional Regulation of Dormancy-Associated Gene Expression by Afterripening in Wild Oat. PLANT PHYSIOLOGY 1996; 110:1267-1273. [PMID: 12226258 PMCID: PMC160920 DOI: 10.1104/pp.110.4.1267] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
To investigate whether the afterripening-induced changes in gene expression are at the transcriptional or posttranscriptional level in wild oat (Avena fatua) seeds, we chose four dormancy-associated genes to estimate their relative transcription activities and the stability of their corresponding transcripts in afterripened and dormant embryos. The transcription activities for those genes were 1.5 to 7 times higher in dormant embryos than in afterripened embryos 24 h after incubation, as determined by nuclear run-on assays. The half-lives of the transcripts in afterripened and dormant embryos were estimated by the use of actinomycin D. The application of actinomycin D resulted in the stabilization of the transcripts. Nevertheless, the results indicated that the half-lives of the transcripts were much greater in dormant embryos than in afterripened embryos. Considering the great differences in the steady-state levels and the half-lives of the mRNAs, and the relatively small differences in transcription activities of the genes between afterripened and dormant embryos, we conclude that afterripening regulates the expression of dormancy-associated genes in excised embryos mainly at the posttranscriptional level and that transcriptional control plays a minor role.
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Affiliation(s)
- Bailin. Li
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907-1155
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25
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Gil P, Green PJ. Multiple regions of the Arabidopsis SAUR-AC1 gene control transcript abundance: the 3' untranslated region functions as an mRNA instability determinant. EMBO J 1996; 15:1678-86. [PMID: 8612592 PMCID: PMC450079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The small-auxin-up-RNA (SAUR) transcripts are rapidly induced by auxin and are among the most short-lived mRNAs in higher plants. In this study, we investigate the regulation of SAUR-AC1, a well characterized SAUR gene of Arabidopsis. Be examining the expression of chimeric genes in transgenic tobacco, we demonstrate that the promoter region of SAUR-AC1 mediates auxin induction. Sequences downstream of the promoter region were found to limit mRNA accumulation in a manner that was independent of auxin treatment. Both the coding region and the 3' untranslated region (UTR) of SAUR-AC1 independently contribute to this limitation. Effects on mRNA stability were assayed using chimeric genes under the control of the tetracycline-repressible Top10 promoter. mRNA half-life analysis following tetracycline treatment showed that the SAUR-AC1 coding region does not contain elements that decrease mRNA stability. In contrast, the 3' UTR was found to act as a potent mRNA instability determinant. This finding and the general utility of the Top10 system should provide the means to elucidate mRNA decay pathways that are potentially novel and specific for certain unstable transcripts.
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MESH Headings
- Arabidopsis/genetics
- Arabidopsis/metabolism
- Arabidopsis Proteins
- Drug Stability
- Gene Expression Regulation, Plant/drug effects
- Genes, Plant
- Genes, Reporter
- Indoleacetic Acids/pharmacology
- Plant Proteins/genetics
- Plants, Genetically Modified
- Plants, Toxic
- Promoter Regions, Genetic
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Plant/genetics
- RNA, Plant/metabolism
- Nicotiana/genetics
- Nicotiana/metabolism
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Affiliation(s)
- P Gil
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing 48824-1312, USA
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26
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Wu G, Shortt BJ, Lawrence EB, Levine EB, Fitzsimmons KC, Shah DM. Disease resistance conferred by expression of a gene encoding H2O2-generating glucose oxidase in transgenic potato plants. THE PLANT CELL 1995; 7:1357-68. [PMID: 8589621 PMCID: PMC160957 DOI: 10.1105/tpc.7.9.1357] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Plant defense responses to pathogen infection involve the production of active oxygen species, including hydrogen peroxide (H2O2). We obtained transgenic potato plants expressing a fungal gene encoding glucose oxidase, which generates H2O2 when glucose is oxidized. H2O2 levels were elevated in both leaf and tuber tissues of these plants. Transgenic potato tubers exhibited strong resistance to a bacterial soft rot disease caused by Erwinia carotovora subsp carotovora, and disease resistance was sustained under both aerobic and anaerobic conditions of bacterial infection. This resistance to soft rot was apparently mediated by elevated levels of H2O2, because the resistance could be counteracted by exogenously added H2O2-degrading catalase. The transgenic plants with increased levels of H2O2 also exhibited enhanced resistance to potato late blight caused by Phytophthora infestans. The development of lesions resulting from infection by P. infestans was significantly delayed in leaves of these plants. Thus, the expression of an active oxygen species-generating enzyme in transgenic plants represents a novel approach for engineering broad-spectrum disease resistance in plants.
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Affiliation(s)
- G Wu
- Monsanto Company, St. Louis, Missouri 63198, USA
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27
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Sessa G, Yang XQ, Raz V, Eyal Y, Fluhr R. Dark induction and subcellular localization of the pathogenesis-related PRB-1b protein. PLANT MOLECULAR BIOLOGY 1995; 28:537-47. [PMID: 7632922 DOI: 10.1007/bf00020400] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The PRB-1b gene codes for a basic-type pathogenesis-related protein of the PR-1 family of tobacco. PRB-1b mRNA accumulation is induced in response to biotic and abiotic elicitors, such as TMV, ethylene, salicylic acid, alpha-amino butyric acid and darkness. In order to determine the location of elements that control dark-regulated PRB-1b gene expression, we tested promoter, transcribed regions and 3'-downstream regions of the gene for their ability to respond to dark induction in transgenic tobacco plants. An ethylene-inducible promoter region of 863 bp was not able to confer dark induction to a beta-glucuronidase reporter gene, while a construct containing the transcribed region of the gene and 3'-downstream sequences, driven by the cauliflower mosaic virus 35S promoter, was correctly dark-regulated. The results indicate that dark-induction of the PRB-1b gene can be controlled by 3'-downstream elements at the transcriptional level or by transcribed sequences at the post-transcriptional level. A circadian clock regulation of the PRB-1b gene was excluded, as fluctuations of PRB-1b transcript levels were not observed in plants placed in constant light or darkness. Subcellular localization of the PRB-1b protein was also determined, in tobacco protoplasts preparations and in cell cultures. The PRB-1b polypeptide was predominantly detected in protoplast vacuoles and was not secreted to the media in cell cultures. These results support an intracellular localization for the PRB-1b protein, as reported for other basic-type components of the pathogenesis-related proteins family.
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Affiliation(s)
- G Sessa
- Department of Plant Genetics, Weizmann Institute of Science, Rehovot, Israel
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28
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Taylor CB, Green PJ. Identification and characterization of genes with unstable transcripts (GUTs) in tobacco. PLANT MOLECULAR BIOLOGY 1995; 28:27-38. [PMID: 7787185 DOI: 10.1007/bf00042035] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Plants and other higher eukaryotes have the ability to recognize and target specific transcripts for rapid decay from among the majority of relatively stable mRNAs present within cells. However, little is known about the nature of unstable transcripts in plants, or the mechanisms that facilitate their rapid degradation. As a first step toward understanding how plants distinguish between unstable and stable transcripts, a novel differential screen was used to identify cDNAs for genes with unstable transcripts (GUTs), solely on the basis of the instability of their mRNAs. cDNA probes were prepared from tobacco cells that had been depleted of highly unstable mRNAs by treatment for 90 min with a transcriptional inhibitor, and from control, untreated cells. GUT clones were selected on the basis of weak hybridization to the former probe relative to the latter probe. Half-life measurements performed on the mRNAs hybridizing to eight GUT clones indicated that each was unstable, with a half-life on the order of about an hour or less. All eight of the cDNAs corresponded to new tobacco genes, and four showed sequence similarity with genes from other species, including the eukaryotic family of DNAJ homologs, a tomato wound-inducible protein, and histone H3. In addition to providing information about the types of transcripts that are inherently unstable in plants, the GUT clones should provide excellent tools for the identification of cis- and trans-acting determinants of mRNA instability.
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Affiliation(s)
- C B Taylor
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing 48824-1312, USA
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29
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Abrahams S, Hayes CM, Watson JM. Expression patterns of three genes in the stem of lucerne (Medicago sativa). PLANT MOLECULAR BIOLOGY 1995; 27:513-528. [PMID: 7894016 DOI: 10.1007/bf00019318] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We have identified three stem abundantly expressed genes in lucerne (alfalfa, Medicago sativa). A cDNA library, constructed from lucerne stem polyadenylated RNA, was screened by differential hybridization. From this screening, cDNA clones that correspond to genes which are preferentially, or specifically, expressed in the stem were isolated. MsaS1 encodes an unidentified protein, MsaS2 encodes an S-adenosyl-homocysteine hydrolase and MsaS3 encodes an extensin-like protein. Northern blot analysis of RNA isolated from individual stem internodes indicated that the three corresponding genes show differing developmental patterns of expression. The expression of MsaS1 was confined to the youngest stem tissue and may be regulated by sucrose. In stem tissue the level of RNA for the three genes decreased in response to wounding. Tissue print hybridization analysis was used to localize the expression of the genes to the xylem side of vascular bundles in lucerne stems.
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Affiliation(s)
- S Abrahams
- CSIRO Division of Plant Industry, Canberra, Australia
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30
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Deutch CE, Winicov I. Post-transcriptional regulation of a salt-inducible alfalfa gene encoding a putative chimeric proline-rich cell wall protein. PLANT MOLECULAR BIOLOGY 1995; 27:411-8. [PMID: 7888629 DOI: 10.1007/bf00020194] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
A cDNA previously shown to identify a salt-inducible root-specific transcript in Medicago sativa was used to screen an alfalfa library for the corresponding genomic sequence. One positive clone was recovered. The nucleotide sequence of a subclone contained a 329 bp 5' region upstream of the first ATG codon, a 1143 bp coding segment, and a 447 bp 3'-untranslated region interrupted by a single 475 bp intron. Translation of the coding segment, which was designated MsPRP2, suggested it encodes a chimeric 40,569 Da cell wall protein with an amino-terminal signal sequence, a repetitive proline-rich sequence, and a cysteine-rich carboxyl-terminal sequence homologous to nonspecific lipid transfer proteins. The 3'-untranslated region of MsPRP2 contained a sequence similar to one found to destabilize mRNAs transcribed from the elicitor-regulated proline-rich protein gene PvPRP1. Transcription run-on experiments using nuclei from salt-sensitive and salt-tolerant alfalfa callus suggested that the accumulation of MsPRP2 transcripts in salt-tolerant alfalfa cells grown in the presence of salt is due primarily to increased mRNA stability. The MsPRP2 gene thus may be a useful model for studying post-transcriptional salt-regulated expression of cell wall proteins.
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MESH Headings
- Amino Acid Sequence
- Base Sequence
- Cell Wall/chemistry
- Cloning, Molecular
- Gene Expression Regulation, Plant/drug effects
- Genes, Plant/genetics
- Medicago sativa/genetics
- Molecular Sequence Data
- Plant Proteins/chemistry
- Plant Proteins/genetics
- RNA, Messenger/biosynthesis
- RNA, Messenger/metabolism
- RNA, Plant/biosynthesis
- RNA, Plant/metabolism
- Sequence Alignment
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Sequence Homology, Nucleic Acid
- Sodium Chloride/pharmacology
- Transcription, Genetic
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Affiliation(s)
- C E Deutch
- Department of Biochemistry, University of Nevada, Reno 89557
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31
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Mehdy MC. Active Oxygen Species in Plant Defense against Pathogens. PLANT PHYSIOLOGY 1994; 105:467-472. [PMID: 12232215 PMCID: PMC159383 DOI: 10.1104/pp.105.2.467] [Citation(s) in RCA: 400] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Affiliation(s)
- M. C. Mehdy
- Department of Botany, University of Texas, Austin, Texas 78713
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32
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Sullivan ML, Green PJ. Post-transcriptional regulation of nuclear-encoded genes in higher plants: the roles of mRNA stability and translation. PLANT MOLECULAR BIOLOGY 1993; 23:1091-104. [PMID: 8292775 DOI: 10.1007/bf00042344] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Affiliation(s)
- M L Sullivan
- MSU-DOE Plant Research Laboratory, E. Lansing 48824-1312
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