151
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Zulak KG, Bohlmann J. Terpenoid biosynthesis and specialized vascular cells of conifer defense. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2010; 52:315-23. [PMID: 20074143 DOI: 10.1111/j.1744-7909.2010.00912.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Defense-related terpenoid biosynthesis in conifers is a dynamic process closely associated with specialized anatomical structures that allows conifers to cope with attack from many potential pests and pathogens. The constitutive and inducible terpenoid defense of conifers involves several hundred different monoterpenes, sesquiterpenes and diterpenes. Changing arrays of these many compounds are formed from the general isoprenoid pathway by activities of large gene families for two classes of enzymes, the terpene synthases and the cytochrome P450-dependent monooxygenases of the CYP720B group. Extensive studies have been conducted on the genomics, proteomics and molecular biochemical characterization of these enzymes. Many of the conifer terpene synthases are multi-product enzymes, and the P450 enzymes of the CYP720B group are promiscuous in catalyzing multiple oxidations, along homologous series of diterpenoids, from a broad spectrum of substrates. The terpene synthases and CYP720B genes respond to authentic or simulated insect attack with increased transcript levels, protein abundance and enzyme activity. The constitutive and induced oleoresin terpenoids for conifer defense accumulate in preformed cortical resin ducts and in xylem trauma-associated resin ducts. Formation of these resin ducts de novo in the cambium zone and developing xylem, following insect attack or treatment of trees with methyl jasmonate, is a unique feature of the induced defense of long-lived conifer trees.
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Affiliation(s)
- Katherine G Zulak
- Michael Smith Laboratories, University of British Columbia, Vancouver BC V6T 1Z4, Canada
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152
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Cutler SR, Rodriguez PL, Finkelstein RR, Abrams SR. Abscisic acid: emergence of a core signaling network. ANNUAL REVIEW OF PLANT BIOLOGY 2010; 61:651-79. [PMID: 20192755 DOI: 10.1146/annurev-arplant-042809-112122] [Citation(s) in RCA: 1756] [Impact Index Per Article: 125.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Abscisic acid (ABA) regulates numerous developmental processes and adaptive stress responses in plants. Many ABA signaling components have been identified, but their interconnections and a consensus on the structure of the ABA signaling network have eluded researchers. Recently, several advances have led to the identification of ABA receptors and their three-dimensional structures, and an understanding of how key regulatory phosphatase and kinase activities are controlled by ABA. A new model for ABA action has been proposed and validated, in which the soluble PYR/PYL/RCAR receptors function at the apex of a negative regulatory pathway to directly regulate PP2C phosphatases, which in turn directly regulate SnRK2 kinases. This model unifies many previously defined signaling components and highlights the importance of future work focused on defining the direct targets of SnRK2s and PP2Cs, dissecting the mechanisms of hormone interactions (i.e., cross talk) and defining connections between this new negative regulatory pathway and other factors implicated in ABA signaling.
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Affiliation(s)
- Sean R Cutler
- Department of Botany and Plant Sciences, University of California, Riverside, California 92521, USA.
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153
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Collinge DB, Jørgensen HJL, Lund OS, Lyngkjaer MF. Engineering pathogen resistance in crop plants: current trends and future prospects. ANNUAL REVIEW OF PHYTOPATHOLOGY 2010; 48:269-91. [PMID: 20687833 DOI: 10.1146/annurev-phyto-073009-114430] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Transgenic crops are now grown commercially in 25 countries worldwide. Although pathogens represent major constraints for the growth of many crops, only a tiny proportion of these transgenic crops carry disease resistance traits. Nevertheless, transgenic disease-resistant plants represent approximately 10% of the total number of approved field trials in North America, a proportion that has remained constant for 15 years. In this review, we explore the socioeconomic and biological reasons for the paradox that although technically useful solutions now exist for providing transgenic disease resistance, very few new crops have been introduced to the global market. For bacteria and fungi, the majority of transgenic crops in trials express antimicrobial proteins. For viruses, three-quarters of the transgenics express coat protein (CP) genes. There is a notable trend toward more biologically sophisticated solutions involving components of signal transduction pathways regulating plant defenses. For viruses, RNA interference is increasingly being used.
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Affiliation(s)
- David B Collinge
- Department of Plant Biology and Biotechnology, Faculty of Life Sciences, University of Copenhagen, Denmark.
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154
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Peng H, Cheng HY, Yu XW, Shi QH, Zhang H, Li JG, Ma H. Characterization of a chickpea (Cicer arietinum L.) NAC family gene, CarNAC5, which is both developmentally- and stress-regulated. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2009; 47:1037-45. [PMID: 19800808 DOI: 10.1016/j.plaphy.2009.09.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2009] [Revised: 07/21/2009] [Accepted: 09/06/2009] [Indexed: 05/09/2023]
Abstract
It has been documented that the plant-specific NAC (for NAM, ATAF1,2 and CUC2) transcription factors play an important role in plant development and stress responses. In this study, a chickpea NAC gene CarNAC5 (for Cicer arietinum L. NAC gene 5) was isolated from a cDNA library from chickpea leaves treated by polyethylene glycol (PEG). CarNAC5, as a single/low copy gene, contained three exons and two introns within genomic DNA sequence and encoded a polypeptide with 291 amino acids. CarNAC5 protein had a conserved NAC domain in the N-terminus and showed high similarity to other NACs, especially ATAF subgroup members. The CarNAC5:GFP fusion protein was localized in the nucleus of onion epidermal cells. Furthermore, CarNAC5 protein activated the reporter genes LacZ and HIS3 in yeast. The transactivation activity was mapped to the C-terminal region. The transcripts of CarNAC5 appeared in many chickpea tissues including seedling leaves, stems, roots, flowers, seeds and pods, but mostly accumulated in flowers. Meanwhile, CarNAC5 was strongly expressed during seed maturation and in embryos of the early germinating seeds. It was also significantly induced by drought, heat, wounding, salicylic acid (SA), and indole-3-acetic acid (IAA) treatments. Our results suggest that CarNAC5 encodes a novel NAC-domain protein and acts as a transcriptional activator involved in plant developmental regulation and various stress responses.
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Affiliation(s)
- Hui Peng
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, National Center for Soybean Improvement, Nanjing Agricultural University, Nanjing 210095, China
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155
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Wang X, Basnayake BMVS, Zhang H, Li G, Li W, Virk N, Mengiste T, Song F. The Arabidopsis ATAF1, a NAC transcription factor, is a negative regulator of defense responses against necrotrophic fungal and bacterial pathogens. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2009; 22:1227-38. [PMID: 19737096 DOI: 10.1094/mpmi-22-10-1227] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Transcription factors of the NAC family are known to be involved in various growth or developmental processes and in regulation of response to environmental stresses. In the present study, we report that Arabidopsis ATAF1 is a negative regulator of defense responses against both necrotrophic fungal and bacterial pathogens. Expression of ATAF1 was downregulated after infection with Botrytis cinerea or Pseudomonas syringae pv. tomato or after treatment with salicylic acid (SA), jasmonic acid, and 1-amino cyclopropane-1-carboxylic acid (the precursor of ethylene biosynthesis). Transgenic plants that overexpress the ATAF1 gene (ATAF1-OE) showed increased susceptibility while expression of an ATAF1 chimeric repressor construct (ATAF1-SRDX) exhibited enhanced resistance to P. syringae pv. tomato DC3000, B. cinerea, and Alternaria brassicicola. The ataf1 mutant plants showed no significant resistance against the pathogens tested. After inoculation with B. cinerea or P. syringae pv. tomato DC3000, expressions of defense-related genes PR-1, PR-5. and PDF1.2 were upregulated in the ATAF1-SRDX plants but attenuated or unchanged in the ATAF1-OE plants. In ATAF1-OE plants, SA-induced expression of pathogenesis-related genes and disease resistance against P. syringae pv. tomato DC3000 was partially suppressed. Increased levels of reactive oxygen species (i.e., H(2)O(2) and superoxide anion) accumulated only in the ATAF1-OE but not in the ATAF1-SRDX plants after Botrytis spp. infection. Our studies provide direct genetic evidence for the role of ATAF1 as a negative regulator of defense response against different type of pathogens.
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Affiliation(s)
- Xiao'e Wang
- State Key Laboratory for Rice Biology, Institute of Biotechnology, Zhejiang University-Huajiachi Campus, Hangzhou, Zhejiang 310029, People's Republic of China
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156
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Abstract
NAC family genes encode plant-specific transcription factors involved in diverse biological processes. In this study, the Arabidopsis NAC gene ATAF1 was found to be induced by drought, high-salinity, abscisic acid (ABA), methyl jasmonate, mechanical wounding, and Botrytis cinerea infection. Significant induction of ATAF1 was found in an ABA-deficient mutant aba2 subjected to drought or high salinity, revealing an ABA-independent mechanism of expression. Arabidopsis ATAF1-overexpression lines displayed many altered phenotypes, including dwarfism and short primary roots. Furthermore, in vivo experiments indicate that ATAF1 is a bona fide regulator modulating plant responses to many abiotic stresses and necrotrophic-pathogen infection. Overexpression of ATAF1 in Arabidopsis increased plant sensitivity to ABA, salt, and oxidative stresses. Especially, ATAF1 overexpression plants, but not mutant lines, showed remarkably enhanced plant tolerance to drought. Additionally, ATAF1 overexpression enhanced plant susceptibility to the necrotrophic pathogen B. cinerea, but did not alter disease symptoms caused by avirulent or virulent strains of P. syringae pv tomato DC3000. Transgenic plants overexpressing ATAF1 were hypersensitive to oxidative stress, suggesting that reactive oxygen intermediates may be related to ATAF1-mediated signaling in response to both pathogen and abiotic stresses.
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157
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Li DM, Staehelin C, Zhang YS, Peng SL. Identification of genes differentially expressed in Mikania micrantha during Cuscuta campestris infection by suppression subtractive hybridization. JOURNAL OF PLANT PHYSIOLOGY 2009; 166:1423-35. [PMID: 19328592 DOI: 10.1016/j.jplph.2009.02.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2008] [Revised: 02/06/2009] [Accepted: 02/07/2009] [Indexed: 05/07/2023]
Abstract
The influence of Cuscuta campestris on its host Mikania micrantha has been studied with respect to biomass accumulation, physiology and ecology. Molecular events of this parasitic plant-plant interaction are poorly understood, however. In this study, we identified novel genes from M. micrantha induced by C. campestris infection. Genes expressed upon parasitization by C. campestris at early post-penetration stages were investigated by construction and characterization of subtracted cDNA libraries from shoots and stems of M. micrantha. Three hundred and three presumably up-regulated expressed sequence tags (ESTs) were identified and classified in functional categories, such as "metabolism", "cell defence and stress", "transcription factor", "signal transduction", "transportation" and "photosynthesis". In shoots and stems of infected M. micrantha, genes associated with defence responses and cell wall modifications were induced, confirming similar data from other parasitic plant-plant interactions. However, gene expression profiles in infected shoots and stems were found to be different. Compared to infected shoots, more genes induced in response to biotic and abiotic stress factors were identified in infected stems. Furthermore, database comparisons revealed a notable number of M. micrantha ESTs that matched genes with unknown function. Expression analysis by quantitative real-time RT-PCR of 21 genes (from different functional categories) showed significantly increased levels for 13 transcripts in response to C. campestris infection. In conclusion, this study provides an overview of genes from parasitized M. micrantha at early post-penetration stages. The acquired data form the basis for a molecular understanding of host reactions in response to parasitic plants.
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Affiliation(s)
- Dong-Mei Li
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
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158
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Pinheiro GL, Marques CS, Costa MDBL, Reis PAB, Alves MS, Carvalho CM, Fietto LG, Fontes EPB. Complete inventory of soybean NAC transcription factors: sequence conservation and expression analysis uncover their distinct roles in stress response. Gene 2009; 444:10-23. [PMID: 19497355 DOI: 10.1016/j.gene.2009.05.012] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Revised: 05/26/2009] [Accepted: 05/27/2009] [Indexed: 10/20/2022]
Abstract
We performed an inventory of soybean NAC transcription factors, in which 101 NAC domain-containing proteins were annotated into 15 different subgroups, showing a clear relationship between structure and function. The six previously described GmNAC proteins (GmNAC1 to GmNAC6) were located in the nucleus and a transactivation assay in yeast confirmed that GmNAC2, GmNAC3, GmNAC4 and GmNAC5 function as transactivators. We also analyzed the expression of the six NAC genes in response to a variety of stress conditions. GmNAC2, GmNAC3 and GmNAC4 were strongly induced by osmotic stress. GmNAC3 and GmNAC4 were also induced by ABA, JA and salinity but differed in their response to cold. Consistent with an involvement in cell death programs, the transient expression of GmNAC1, GmNAC5 and GmNAC6 in tobacco leaves resulted in cell death and enhanced expression of senescence markers. Our results indicate that the described soybean NACs are functionally non-redundant transcription factors involved in response to abiotic stresses and in cell death events in soybean.
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Affiliation(s)
- Guilherme L Pinheiro
- Departamento de Bioquímica e Biologia Molecular, Laboratório de Biologia Molecular de Plantas, BIOAGRO, Universidade Federal de Viçosa, 36570.000, Viçosa, Minas Gerais, Brazil
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159
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Cloning and characterization of a novel NAC family gene CarNAC1 from chickpea (Cicer arietinum L.). Mol Biotechnol 2009; 44:30-40. [PMID: 19669952 DOI: 10.1007/s12033-009-9202-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2009] [Accepted: 07/28/2009] [Indexed: 10/20/2022]
Abstract
The plant-specific NAC (for NAM, ATAF1,2 and CUC2) proteins have been found to play important roles in plant development and stress responses. In this study, a NAC gene CarNAC1 (for Cicer arietinum L. NAC gene 1) was isolated from a cDNA library constructed with chickpea seedling leaves treated by polyethylene glycol. CarNAC1 encoded a putative protein with 239 amino acids and contained 3 exons and 2 introns within genomic DNA sequence. CarNAC1 had a conserved NAC domain in the N-terminus and the CarNAC1:GFP (green fluorescent protein) fusion protein was localized in the nucleus of onion epidermal cells. Additionally, CarNAC1 exhibited the trans-activation activity which was mapped to the C-terminus. The CarNAC1 transcript was detected in many chickpea organs including seedling leaves, stems, roots, flowers, and young pods, but less accumulated in young seeds. CarNAC1 was induced by leaf age and showed changes in expression during seed development and germination. Furthermore, the expression of CarNAC1 was strongly induced by drought, salt, cold, wounding, H(2)O(2), ethephon, salicylic acid, indole-3-acetic acid, and gibberellin. Our results suggest that CarNAC1 encodes a novel NAC-domain protein and may be a transcriptional activator involved in plant development and various stress responses.
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160
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Tran LSP, Quach TN, Guttikonda SK, Aldrich DL, Kumar R, Neelakandan A, Valliyodan B, Nguyen HT. Molecular characterization of stress-inducible GmNAC genes in soybean. Mol Genet Genomics 2009; 281:647-64. [PMID: 19277718 DOI: 10.1007/s00438-009-0436-8] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2008] [Accepted: 02/18/2009] [Indexed: 10/21/2022]
Abstract
Drought is detrimental to plant growth and development, and often results in significant losses to the yields of economically important crops such as soybeans (Glycine max L.). NAC transcription factors (TFs), which consist of a large family of plant-specific TFs, have been reported to enhance drought tolerance in a number of plants. In this study, 31 unigenes that contain the complete open reading frames encoding GmNAC proteins were identified and cloned from soybean. Analysis of C-terminal regulatory domain using yeast one-hybrid system indicated that among 31 GmNAC proteins, 28 have transcriptional activation activity. Expression analysis of these GmNAC genes showed that they are differentially expressed in different organs, suggesting that they have diverse functions during plant growth and development. To search for the drought-inducible GmNAC genes, we prescreened and re-confirmed by quantitative real-time PCR analysis that nine GmNAC genes are induced by dehydration stress with differential induction levels in both shoot and root. The expression profiles of these nine GmNAC genes were also examined under other stresses such as high salinity, cold and with abscisic acid hormone treatments. Phylogenetic analysis of the GmNAC proteins with previously reported drought-inducible NAC proteins of Arabidopsis and rice revealed that the nine drought-inducible GmNAC proteins belong to the "stress-inducible" NAC group. The results of this systematic analysis of the GmNAC family will provide novel tools and resources for the development of improved drought tolerant transgenic soybean cultivars.
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Affiliation(s)
- Lam-Son Phan Tran
- Division of Plant Sciences, National Center for Soybean Biotechnology, University of Missouri, Columbia, MO 65211, USA.
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161
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Wang B, Sang Y, Song J, Gao XQ, Zhang X. Expression of a rice OsARGOS gene in Arabidopsis promotes cell division and expansion and increases organ size. J Genet Genomics 2009; 36:31-40. [PMID: 19161943 DOI: 10.1016/s1673-8527(09)60004-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Revised: 11/02/2008] [Accepted: 11/18/2008] [Indexed: 12/27/2022]
Abstract
The ARGOS gene in Arabidopsis plays a key role in controlling plant organ size. To determine the function of it's ortholog in rice, a putative ARGOS orthologous gene from rice tissues was isolated and designated as OsARGOS. This gene has only one copy in the rice genome. OsARGOS transcripts were detected in most of rice tissues, particularly in the young tissues, and its expression was induced in rice seedlings by the application of either auxin or cytokinin. Arabidopsis plants expressing OsARGOS led to larger organs, such as leaves and siliques, compared with wild-type plants. Interestingly, the root growth was also enhanced in these transgenic Arabidopsis plants. Therefore, the biomass of the transgenic plants was significantly increased. Further analysis revealed that, different from the ARGOS and ARGOS-LIKE genes in Arabidopsis, the OsARGOS gene enlarged organ by an increase in both cell number and cell size. In addition, the transcript levels of several organ size-associated genes regulating either cell division or cell growth were upregulated in the transgenic Arabidopsis plants. We also transferred the OsARGOS gene to rice, but the transgenic plants did not show any changes in organ size compared with the control plants. It is likely that the function of OsARGOS in organ size control depends on other size regulators in rice. The expression of OsARGOS in Arabidopsis may activate the signaling pathways that control cell proliferation and cell expansion during the course of plant growth and development. Since the expression of OsARGOS causes organ enlargement, the potential application of this gene through genetic engineering may significantly improve the production of biomass in agricultural practice.
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Affiliation(s)
- Bao Wang
- Shandong Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China
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162
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Zheng X, Chen B, Lu G, Han B. Overexpression of a NAC transcription factor enhances rice drought and salt tolerance. Biochem Biophys Res Commun 2009; 379:985-9. [PMID: 19135985 DOI: 10.1016/j.bbrc.2008.12.163] [Citation(s) in RCA: 213] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2008] [Accepted: 12/31/2008] [Indexed: 10/21/2022]
Abstract
The plant-specific NAC (NAM, ATAF1/2, CUC2) transcription factors play diverse roles in plant development and stress responses. In this study, a rice NAC gene, ONAC045, was functionally characterized, especially with regard to its role in abiotic stress resistance. Expression analysis revealed that ONAC045 was induced by drought, high salt, and low temperature stresses, and abscisic acid (ABA) treatment in leaves and roots. Transcriptional activation assay in yeast indicated that ONAC045 functioned as a transcriptional activator. Transient expression of GFP-ONAC045 in onion epidermal cells revealed that ONAC045 protein was localized in the nucleus. Transgenic rice plants overexpressing ONAC045 showed enhanced tolerance to drought and salt treatments. Two stress-responsive genes were upregulated in transgenic rice. Together, these results suggest that ONAC045 encodes a novel stress-responsive NAC transcription factor and is potential useful for engineering drought and salt tolerant rice.
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Affiliation(s)
- Xingnan Zheng
- National Center for Gene Research & Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 500 Caobao Road, Shanghai 200233, China
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163
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Jensen MK, Hagedorn PH, de Torres-Zabala M, Grant MR, Rung JH, Collinge DB, Lyngkjaer MF. Transcriptional regulation by an NAC (NAM-ATAF1,2-CUC2) transcription factor attenuates ABA signalling for efficient basal defence towards Blumeria graminis f. sp. hordei in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2008; 56:867-80. [PMID: 18694460 DOI: 10.1111/j.1365-313x.2008.03646.x] [Citation(s) in RCA: 144] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
ATAF1 is a member of a largely uncharacterized plant-specific gene family encoding NAC transcription factors, and is induced in response to various abiotic and biotic stimuli in Arabidopsis thaliana. Previously, we showed that a mutant allele of ATAF1 compromises penetration resistance in Arabidopsis with respect to the non-host biotrophic pathogen Blumeria graminis f. sp. hordei (Bgh). In this study, we have used genome-wide transcript profiling to characterize signalling perturbations in ataf1 plants following Bgh inoculation. Comparative transcriptomic analyses identified an over-representation of abscisic acid (ABA)-responsive genes, including the ABA biosynthesis gene AAO3, which is significantly induced in ataf1 plants compared to wild-type plants following inoculation with Bgh. Additionally, we show that Bgh inoculation results in decreased endogenous ABA levels in an ATAF1-dependent manner, and that the ABA biosynthetic mutant aao3 showed increased penetration resistance to Bgh compared to wild-type plants. Furthermore, we show that ataf1 plants show ABA-hyposensitive phenotypes during seedling development and germination. Our data support a negative correlation between ABA levels and penetration resistance, and identify ATAF1 as a new stimuli-dependent attenuator of ABA signalling for the mediation of efficient penetration resistance in Arabidopsis upon Bgh attack.
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Affiliation(s)
- Michael K Jensen
- Department of Plant Biology, Faculty of Life Sciences, University of Copenhagen, DK-1871 Frederiksberg C, Denmark
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164
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Chang WC, Wang YK, Liu PF, Tsai YF, Kong LR, Lin CK, Yang CH, Pan RL. Regulation of Ku gene promoters in Arabidopsis by hormones and stress. FUNCTIONAL PLANT BIOLOGY : FPB 2008; 35:265-280. [PMID: 32688782 DOI: 10.1071/fp07249] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2007] [Accepted: 04/29/2008] [Indexed: 06/11/2023]
Abstract
The Ku70/Ku80 heterodimer plays a crucial role in non-homologous end-joining during DNA repair, and is also involved in multiple cellular processes such as telomere maintenance, transcription, and apoptosis. In this study, we investigate the regulation of AtKu genes in higher plants. Promoters of the AtKu70 and AtKu80 were isolated from Arabidopsis and their activities characterised using GUS reporter constructs. AtKu promoter activities were relatively higher in hypocotyls and cotyledons upon germination and in stigma and siliques as well at their early developing stages. Furthermore, AtKu promoter activities could be enhanced by gibberellic acid, auxins, and jasmonic acid, but repressed by abscisic acid, salicylic acid, heat, drought and cold, respectively. Deletion analysis demonstrates minimal lengths of ~400 bp and 600 bp upstream of transcription start site for functional promoters of AtKu70 and AtKu80, respectively. Taken together, expressions of Ku genes are regulated both by developmental programs as well as by plant hormones and environmental stresses.
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Affiliation(s)
- Wen-Chi Chang
- Institute of Bioinformatics and Structural Biology, College of Life Sciences, National Tsing Hua University, Hsin-Chu 30013, Taiwan
| | - Yung-Kai Wang
- Institute of Bioinformatics and Structural Biology, College of Life Sciences, National Tsing Hua University, Hsin-Chu 30013, Taiwan
| | - Pei-Feng Liu
- Institute of Bioinformatics and Structural Biology, College of Life Sciences, National Tsing Hua University, Hsin-Chu 30013, Taiwan
| | - Yu-Fang Tsai
- Institute of Bioinformatics and Structural Biology, College of Life Sciences, National Tsing Hua University, Hsin-Chu 30013, Taiwan
| | - Lih-Ren Kong
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 40227, Taiwan
| | - Chi-Kai Lin
- Institute of Bioinformatics and Structural Biology, College of Life Sciences, National Tsing Hua University, Hsin-Chu 30013, Taiwan
| | - Chang-Hsien Yang
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 40227, Taiwan
| | - Rong-Long Pan
- Institute of Bioinformatics and Structural Biology, College of Life Sciences, National Tsing Hua University, Hsin-Chu 30013, Taiwan
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165
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Ogo Y, Kobayashi T, Nakanishi Itai R, Nakanishi H, Kakei Y, Takahashi M, Toki S, Mori S, Nishizawa NK. A novel NAC transcription factor, IDEF2, that recognizes the iron deficiency-responsive element 2 regulates the genes involved in iron homeostasis in plants. J Biol Chem 2008; 283:13407-17. [PMID: 18308732 DOI: 10.1074/jbc.m708732200] [Citation(s) in RCA: 139] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Iron is essential for most living organisms, and thus iron deficiency poses a major abiotic stress in crop production. Plants induce iron utilization systems under conditions of low iron availability, but the molecular mechanisms of gene regulation under iron deficiency remain largely unknown. We identified a novel transcription factor of rice and barley, IDEF2, which specifically binds to the iron deficiency-responsive cis-acting element 2 (IDE2) by yeast one-hybrid screening. IDEF2 belongs to an uncharacterized branch of the NAC transcription factor family and exhibits novel properties of sequence recognition. An electrophoretic mobility shift assay and cyclic amplification and selection of targets experiment revealed that IDEF2 predominantly recognized CA(A/C)G(T/C)(T/C/A)(T/C/A) within IDE2 as the core-binding site. IDEF2 transcripts are constitutively present in rice roots and leaves. Repression of the function of IDEF2 by the RNA interference (RNAi) technique and chimeric repressor gene-silencing technology (CRES-T) caused aberrant iron homeostasis in rice. Several genes up-regulated by iron deficiency, including the Fe(II)-nicotianamine transporter gene OsYSL2, were less induced by iron deficiency in the RNAi rice of IDEF2, suggesting that IDEF2 is involved in the regulation of these genes. Many genes with repressed expression in IDEF2 RNAi rice possessed the IDEF2-binding core sites in their promoters, and the flanking sequences were also highly homologous to IDE2. IDEF2 bound to OsYSL2 promoter region containing the binding core site, suggesting direct regulation of OsYSL2 expression. These results reveal novel cis-element/trans-factor interactions functionally associated with iron homeostasis.
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Affiliation(s)
- Yuko Ogo
- Graduate School of Agricultural and Life Sciences, the University of Tokyo, 1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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Gómez-Porras JL, Riaño-Pachón DM, Dreyer I, Mayer JE, Mueller-Roeber B. Genome-wide analysis of ABA-responsive elements ABRE and CE3 reveals divergent patterns in Arabidopsis and rice. BMC Genomics 2007; 8:260. [PMID: 17672917 PMCID: PMC2000901 DOI: 10.1186/1471-2164-8-260] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2007] [Accepted: 08/01/2007] [Indexed: 11/16/2022] Open
Abstract
Background In plants, complex regulatory mechanisms are at the core of physiological and developmental processes. The phytohormone abscisic acid (ABA) is involved in the regulation of various such processes, including stomatal closure, seed and bud dormancy, and physiological responses to cold, drought and salinity stress. The underlying tissue or plant-wide control circuits often include combinatorial gene regulatory mechanisms and networks that we are only beginning to unravel with the help of new molecular tools. The increasing availability of genomic sequences and gene expression data enables us to dissect ABA regulatory mechanisms at the individual gene expression level. In this paper we used an in-silico-based approach directed towards genome-wide prediction and identification of specific features of ABA-responsive elements. In particular we analysed the genome-wide occurrence and positional arrangements of two well-described ABA-responsive cis-regulatory elements (CREs), ABRE and CE3, in thale cress (Arabidopsis thaliana) and rice (Oryza sativa). Results Our results show that Arabidopsis and rice use the ABA-responsive elements ABRE and CE3 distinctively. Earlier reports for various monocots have identified CE3 as a coupling element (CE) associated with ABRE. Surprisingly, we found that while ABRE is equally abundant in both species, CE3 is practically absent in Arabidopsis. ABRE-ABRE pairs are common in both genomes, suggesting that these can form functional ABA-responsive complexes (ABRCs) in Arabidopsis and rice. Furthermore, we detected distinct combinations, orientation patterns and DNA strand preferences of ABRE and CE3 motifs in rice gene promoters. Conclusion Our computational analyses revealed distinct recruitment patterns of ABA-responsive CREs in upstream sequences of Arabidopsis and rice. The apparent absence of CE3s in Arabidopsis suggests that another CE pairs with ABRE to establish a functional ABRC capable of interacting with transcription factors. Further studies will be needed to test whether the observed differences are extrapolatable to monocots and dicots in general, and to understand how they contribute to the fine-tuning of the hormonal response. The outcome of our investigation can now be used to direct future experimentation designed to further dissect the ABA-dependent regulatory networks.
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Affiliation(s)
- Judith L Gómez-Porras
- University of Potsdam, Institute of Biochemistry and Biology, Karl-Liebknecht-Str. 24-25, Haus 20, D-14476 Potsdam-Golm, Germany
- Cooperative Research Group of the Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
- University of Bielefeld, Institute of Molecular Cell Physiology, Department of Biology, Universitätsstr. 25, D-33501 Germany
| | - Diego Mauricio Riaño-Pachón
- University of Potsdam, Institute of Biochemistry and Biology, Karl-Liebknecht-Str. 24-25, Haus 20, D-14476 Potsdam-Golm, Germany
- Cooperative Research Group of the Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Ingo Dreyer
- University of Potsdam, Institute of Biochemistry and Biology, Karl-Liebknecht-Str. 24-25, Haus 20, D-14476 Potsdam-Golm, Germany
- Cooperative Research Group of the Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Jorge E Mayer
- Center for Applied Biosciences, University of Freiburg, Stefan-Meier-Str. 8, D-79104 Freiburg, Germany
| | - Bernd Mueller-Roeber
- University of Potsdam, Institute of Biochemistry and Biology, Karl-Liebknecht-Str. 24-25, Haus 20, D-14476 Potsdam-Golm, Germany
- Cooperative Research Group of the Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
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