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Dong J, Chen Y, Xie Y, Cao M, Fu S, Wu J. The Identification of Viral Pathogens in a Physostegia virginiana Plant Using High-Throughput RNA Sequencing. Viruses 2023; 15:1972. [PMID: 37766378 PMCID: PMC10534606 DOI: 10.3390/v15091972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 09/18/2023] [Accepted: 09/20/2023] [Indexed: 09/29/2023] Open
Abstract
Physostegia virginiana is an important ornamental and cut-flower plant in China. Its commonly used method of clonal propagation leads to virus accumulation in this plant. However, which viruses can infect the Physostegia virginiana plant remains to be illuminated. In this work, five viral pathogens in a Physostegia virginiana plant with virus-like symptoms of yellow, shriveled, and curled leaves were identified using RNA-seq, bioinformatics, and molecular biological techniques. These techniques allowed us to identify five viruses comprising one known alfalfa mosaic virus (AMV) and four novel viruses. The novel viruses include a virus belonging to the genus Fabavirus, temporarily named Physostegia virginiana crinkle-associated virus 1 (PVCaV1); two viruses belonging to the genus Caulimovirus, temporarily named Physostegia virginiana caulimovirus 1 and 2 (PVCV1 and PVCV2); and a virus belonging to the genus Fijivirus, temporarily named Physostegia virginiana fijivirus (PVFV). The genome sequences of PVCaV1, PVCV1, and PVCV2, and the partial genome sequence of PVFV were identified. Genome organizations and genetic evolutionary relationships of all four novel viruses were analyzed. PVCaV1 has a relatively close evolutionary relationship with five analyzed fabiviruses. PVCV1 and PVCV2 have separately a closest evolutionary relationship with lamium leaf distortion-associated virus (LLDAV) and figwort mosaic virus (FMV), and PVFV has a close evolutionary relationship with the five analyzed fijiviruses. Additionally, PVCaV1 can infect Nicotiana benthamiana plants via friction inoculation. The findings enrich our understanding of Physostegia virginiana viruses and contribute to the prevention and control of Physostegia virginiana viral diseases.
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Affiliation(s)
- Jinxi Dong
- Hainan Institute, Zhejiang University, Sanya 572025, China; (J.D.); (Y.C.)
- State Key Laboratory of Rice Biology, Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China;
| | - Yuanling Chen
- Hainan Institute, Zhejiang University, Sanya 572025, China; (J.D.); (Y.C.)
- State Key Laboratory of Rice Biology, Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China;
| | - Yi Xie
- State Key Laboratory of Rice Biology, Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China;
| | - Mengji Cao
- National Citrus Engineering and Technology Research Center, Citrus Research Institute, Southwest University, Chongqing 400712, China
| | - Shuai Fu
- Research Center for Biological Computation, Zhejiang Lab, Hangzhou 311100, China
| | - Jianxiang Wu
- Hainan Institute, Zhejiang University, Sanya 572025, China; (J.D.); (Y.C.)
- State Key Laboratory of Rice Biology, Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China;
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2
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Pino LE, Lima JE, Vicente MH, de Sá AFL, Pérez-Alfocea F, Albacete A, Costa JL, Werner T, Schmülling T, Freschi L, Figueira A, Zsögön A, Peres LEP. Increased branching independent of strigolactone in cytokinin oxidase 2-overexpressing tomato is mediated by reduced auxin transport. MOLECULAR HORTICULTURE 2022; 2:12. [PMID: 37789497 PMCID: PMC10514996 DOI: 10.1186/s43897-022-00032-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 04/11/2022] [Indexed: 10/05/2023]
Abstract
Tomato production is influenced by shoot branching, which is controlled by different hormones. Here we produced tomato plants overexpressing the cytokinin-deactivating gene CYTOKININ OXYDASE 2 (CKX2). CKX2-overexpressing (CKX2-OE) plants showed an excessive growth of axillary shoots, the opposite phenotype expected for plants with reduced cytokinin content, as evidenced by LC-MS analysis and ARR5-GUS staining. The TCP transcription factor SlBRC1b was downregulated in the axillary buds of CKX2-OE and its excessive branching was dependent on a functional version of the GRAS-family gene LATERAL SUPPRESSOR (LS). Grafting experiments indicated that increased branching in CKX2-OE plants is unlikely to be mediated by root-derived signals. Crossing CKX2-OE plants with transgenic antisense plants for the strigolactone biosynthesis gene CAROTENOID CLEAVAGE DIOXYGENASE (CCD7-AS) produced an additive phenotype, indicating independent effects of cytokinin and strigolactones on increased branching. On the other hand, CKX2-OE plants showed reduced polar auxin transport and their bud outgrowth was reduced when combined with auxin mutants. Accordingly, CKX2-OE basal buds did not respond to auxin applied in the decapitated apex. Our results suggest that tomato shoot branching depends on a fine-tuning of different hormonal balances and that perturbations in the auxin status could compensate for the reduced cytokinin levels in CKX2-OE plants.
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Affiliation(s)
- Lilian Ellen Pino
- Laboratory of Plant Breeding, Centro de Energia Nuclear na Agricultura, University of Sao Paulo, São Paulo, Brazil
- Laboratory of Hormonal Control of Plant Development, Department of Biological Sciences, Escola Superior de Agricultura 'Luiz de Queiroz'University of Sao Paulo, Piracicaba, Brazil
| | - Joni E Lima
- Botany Department, ICB, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Mateus H Vicente
- Laboratory of Hormonal Control of Plant Development, Department of Biological Sciences, Escola Superior de Agricultura 'Luiz de Queiroz'University of Sao Paulo, Piracicaba, Brazil
| | - Ariadne F L de Sá
- Laboratory of Hormonal Control of Plant Development, Department of Biological Sciences, Escola Superior de Agricultura 'Luiz de Queiroz'University of Sao Paulo, Piracicaba, Brazil
| | | | - Alfonso Albacete
- Department of Plant Nutrition, CEBAS-CSIC, Campus Univ. Espinardo, Murcia, Spain
| | - Juliana L Costa
- Laboratory of Plant Breeding, Centro de Energia Nuclear na Agricultura, University of Sao Paulo, São Paulo, Brazil
| | - Tomáš Werner
- Institute of Biology/Applied Genetics, Freie Universität Berlin, Berlin, Germany
- Institute of Biology, University of Graz, Schubertstraße 51, 8010, Graz, Austria
| | - Thomas Schmülling
- Institute of Biology/Applied Genetics, Freie Universität Berlin, Berlin, Germany
| | - Luciano Freschi
- Biosciences Institute, University of Sao Paulo, São Paulo, Brazil
| | - Antonio Figueira
- Laboratory of Plant Breeding, Centro de Energia Nuclear na Agricultura, University of Sao Paulo, São Paulo, Brazil
| | - Agustin Zsögön
- Plant Sciences Department, Federal University of Viçosa, Viçosa, Brazil
| | - Lázaro E P Peres
- Laboratory of Hormonal Control of Plant Development, Department of Biological Sciences, Escola Superior de Agricultura 'Luiz de Queiroz'University of Sao Paulo, Piracicaba, Brazil.
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3
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Complete genome sequence of pueraria virus A, a new member of the genus Caulimovirus. Arch Virol 2022; 167:1481-1485. [PMID: 35451686 DOI: 10.1007/s00705-022-05431-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 02/22/2022] [Indexed: 11/02/2022]
Abstract
The complete genome sequence of a new caulimovirus in Pueraria montana was determined using high-throughput sequencing. The 7,572 nucleotide genome of pueraria virus A (PVA) contains genes that encode a movement protein, an aphid transmission factor, a virion-associated protein, a coat protein, a protease + reverse transcriptase + ribonuclease H, and a transactivator/viroplasmin protein, as well as two intergenic regions, which are all common features of members of the genus Caulimovirus. A sequence alignment revealed that the complete genome of PVA shares 66.82% nucleotide sequence identity with strawberry vein banding virus (GenBank accession no. KX249738.1). The results of phylogenetic analysis and the observation that the nucleotide sequence of the polymerase coding region differed by more than 20% indicated that PVA is a member of a new species the genus Caulimovirus, family Caulimoviridae.
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4
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Alotaibi SS. Developing specific leaf promoters tools for genetic use in transgenic plants towards food security. Saudi J Biol Sci 2021; 28:5187-5192. [PMID: 34466096 PMCID: PMC8380998 DOI: 10.1016/j.sjbs.2021.05.046] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 05/16/2021] [Accepted: 05/18/2021] [Indexed: 11/28/2022] Open
Abstract
Significant yields enrichments are necessitated for meeting the rapid global growth population together with the expected demanding for food, particularly major crops. Photosynthesis improvement is an unexploited opportunity in research on improving crop yields. However, the lack of sufficient molecular promoters tools leads to the need to explore and analyze native leaf-specified promoters for manipulating photosynthesis activities in plants. Two B. distachyon promoters, sedoheptulose-1, 7-bisphosphatase (SBPase) and fructose-1, 6-bisphosphate aldolase (FBPA), were isolated and cloned into an expression vector upstream of the eYFP reporter gene. The results demonstrate that both promoters actively function in N. benthamiana leaves in both agro-transiently assays, successfully regulating expression specifically to leaf-tissues. Exploring these active promoters could potentially provide new well genetic tools for any transgene expression in plants or leaves to genetically manipulate photosynthesis for yield improvement.
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Affiliation(s)
- Saqer S Alotaibi
- Biotechnology Department, College of Science, Taif University, P.O. BOX 11099, Taif 21944, Saudi Arabia
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5
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López-Calcagno PE, Brown KL, Simkin AJ, Fisk SJ, Vialet-Chabrand S, Lawson T, Raines CA. Stimulating photosynthetic processes increases productivity and water-use efficiency in the field. NATURE PLANTS 2020; 6:1054-1063. [PMID: 32782406 DOI: 10.1038/s41477-020-0740-1] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 07/08/2020] [Indexed: 05/20/2023]
Abstract
Previous studies have demonstrated that the independent stimulation of either electron transport or RuBP regeneration can increase the rate of photosynthetic carbon assimilation and plant biomass. In this paper, we present evidence that a multigene approach to simultaneously manipulate these two processes provides a further stimulation of photosynthesis. We report on the introduction of the cyanobacterial bifunctional enzyme fructose-1,6-bisphosphatase/sedoheptulose-1,7-bisphosphatase or the overexpression of the plant enzyme sedoheptulose-1,7-bisphosphatase, together with the expression of the red algal protein cytochrome c6, and show that a further increase in biomass accumulation under both glasshouse and field conditions can be achieved. Furthermore, we provide evidence that the stimulation of both electron transport and RuBP regeneration can lead to enhanced intrinsic water-use efficiency under field conditions.
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Affiliation(s)
| | - Kenny L Brown
- School of Life Sciences, University of Essex, Colchester, UK
| | - Andrew J Simkin
- School of Life Sciences, University of Essex, Colchester, UK
- Genetics, Genomics and Breeding, NIAB EMR, East Malling, UK
| | - Stuart J Fisk
- School of Life Sciences, University of Essex, Colchester, UK
| | | | - Tracy Lawson
- School of Life Sciences, University of Essex, Colchester, UK
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6
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Shrestha A, Khan A, Dey N. Identification of Novel Pararetroviral Promoters for Designing Efficient Plant Gene Expression Systems. Methods Mol Biol 2019; 1991:207-222. [PMID: 31041775 DOI: 10.1007/978-1-4939-9458-8_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2023]
Abstract
Plant-infecting viruses, particularly the Pararetroviruses, have been used for many years as versatile genetic resources to design efficient plant expression vectors. The Pararetroviruses (members of the Caulimoviridae) typically contain two transcriptional promoters (the sub-genomic transcript promoter and the full-length transcript promoter) and 6-7 overlapping open reading frames (ORFs) with a genome size of 7-9 kB. Their promoter elements have been extensively exploited during the last two decades to construct effective gene expression systems. At the same time, the caulimoviral promoters have also been genetically manipulated with different molecular approaches to develop synthetic "chimeras" exhibiting precise functionality. Native and "tailor-made" synthetic promoters of Pararetroviruses are particularly attractive for formulating unique gene expression cassettes that perform extremely well in gene-stacking and gene-pyramiding in plant cells. In this chapter, we will mainly discuss important protocols associated with identifying novel/unique pararetroviral promoters that have optimal lengths with appropriate activities for developing efficient plant gene expression systems.
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Affiliation(s)
- Ankita Shrestha
- Division of Plant and Microbial Biotechnology, Institute of Life Sciences, Government of India, Bhubaneswar, Odisha, India
| | - Ahamed Khan
- Division of Plant and Microbial Biotechnology, Institute of Life Sciences, Government of India, Bhubaneswar, Odisha, India
| | - Nrisingha Dey
- Division of Plant and Microbial Biotechnology, Institute of Life Sciences, Government of India, Bhubaneswar, Odisha, India.
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7
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Ranu RS, Gowda S, Scholthof H, Wu FC, Shepherd RJ. In vitro translation of the full-length RNA transcript of figwort mosaic virus (Caulimovirus). Gene Expr 2018; 5:143-53. [PMID: 8882638 PMCID: PMC6138018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The circular DNA genome of FMV consists of seven tandemly arranged genes placed successively on a full-length RNA transcript that spans the entire circular viral genome. This transcript is a tentative mRNA for at least five of the six major conserved genes of this virus (genes I-V) that are positioned on this transcript. The sixth major gene (gene VI) is expressed as a separate monocistronic transcript. A long 5'-nontranslated leader (598 nucleotides), a small nonconserved gene (VII), and a short intergenic region (57 nucleotides) precede the five major conserved genes (I through V) on the full-length transcript. A reporter gene (CAT), as a separate cistron or fused in-frame, to viral cistrons in various downstream positions in cloned versions of the viral genome was used in a transcription vector to generate artificial full-length transcripts of FMV. When these mRNAs were translated in vitro (rabbit reticulocyte lysate system), the reporter gene was translated efficiently in all positions. Translation of internal native viral gene positioned on the full-length transcript of FMV was also determined (the gene VI product). These observations suggest that the full-length FMV transcript functions as a polycistronic mRNA in plants. Results are best explained on the basis of translational coupling/relay race model.
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Affiliation(s)
- R S Ranu
- Department of Plant Pathology and Weed Science, Colorado State University, Fort Collins 80523, USA
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8
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Garbowicz K, Liu Z, Alseekh S, Tieman D, Taylor M, Kuhalskaya A, Ofner I, Zamir D, Klee HJ, Fernie AR, Brotman Y. Quantitative Trait Loci Analysis Identifies a Prominent Gene Involved in the Production of Fatty Acid-Derived Flavor Volatiles in Tomato. MOLECULAR PLANT 2018; 11:1147-1165. [PMID: 29960108 DOI: 10.1016/j.molp.2018.06.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 06/12/2018] [Accepted: 06/13/2018] [Indexed: 06/08/2023]
Abstract
To gain insight into the genetic regulation of lipid metabolism in tomato, we conducted metabolic trait loci (mQTL) analysis following the lipidomic profiling of fruit pericarp and leaf tissue of the Solanum pennellii introgression lines (IL). To enhance mapping resolution for selected fruit-specific mQTL, we profiled the lipids in a subset of independently derived S. pennellii backcross inbred lines, as well as in a near-isogenic sub-IL population. We identified a putative lecithin:cholesterol acyltransferase that controls the levels of several lipids, and two members of the class III lipase family, LIP1 and LIP2, that were associated with decreased levels of diacylglycerols (DAGs) and triacylglycerols (TAGs). Lipases of this class cleave fatty acids from the glycerol backbone of acylglycerols. The released fatty acids serve as precursors of flavor volatiles. We show that LIP1 expression correlates with fatty acid-derived volatile levels. We further confirm the function of LIP1 in TAG and DAG breakdown and volatile synthesis using transgenic plants. Taken together, our study extensively characterized the genetic architecture of lipophilic compounds in tomato and demonstrated at molecular level that release of free fatty acids from the glycerol backbone can have a major impact on downstream volatile synthesis.
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Affiliation(s)
- Karolina Garbowicz
- Max-Planck-Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | - Zhongyuan Liu
- Horticultural Sciences, Plant Innovation Center, University of Florida, Gainesville, FL, USA
| | - Saleh Alseekh
- Max-Planck-Institute of Molecular Plant Physiology, Potsdam-Golm, Germany; Center of Plant System Biology and Biotechnology, 4000 Plovdiv, Bulgaria
| | - Denise Tieman
- Horticultural Sciences, Plant Innovation Center, University of Florida, Gainesville, FL, USA
| | - Mark Taylor
- Horticultural Sciences, Plant Innovation Center, University of Florida, Gainesville, FL, USA
| | | | - Itai Ofner
- Robert H. Smith Institute of Plant Sciences and Genetics, Faculty of Agriculture, Hebrew University of Jerusalem, Rehovot 7610001, Israel
| | - Dani Zamir
- Robert H. Smith Institute of Plant Sciences and Genetics, Faculty of Agriculture, Hebrew University of Jerusalem, Rehovot 7610001, Israel
| | - Harry J Klee
- Horticultural Sciences, Plant Innovation Center, University of Florida, Gainesville, FL, USA
| | - Alisdair R Fernie
- Max-Planck-Institute of Molecular Plant Physiology, Potsdam-Golm, Germany; Center of Plant System Biology and Biotechnology, 4000 Plovdiv, Bulgaria
| | - Yariv Brotman
- Department of Life Sciences, Ben-Gurion University of the Negev, Beersheba, Israel.
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9
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Alotaibi SS, Sparks CA, Parry MAJ, Simkin AJ, Raines CA. Identification of Leaf Promoters for Use in Transgenic Wheat. PLANTS 2018; 7:plants7020027. [PMID: 29597282 PMCID: PMC6027260 DOI: 10.3390/plants7020027] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Revised: 03/06/2018] [Accepted: 03/23/2018] [Indexed: 12/26/2022]
Abstract
Wheat yields have plateaued in recent years and given the growing global population there is a pressing need to develop higher yielding varieties to meet future demand. Genetic manipulation of photosynthesis in elite wheat varieties offers the opportunity to significantly increase yields. However, the absence of a well-defined molecular tool-box of promoters to manipulate leaf processes in wheat hinders advancements in this area. Two promoters, one driving the expression of sedoheptulose-1,7-bisphosphatase (SBPase) and the other fructose-1,6-bisphosphate aldolase (FBPA) from Brachypodium distachyon were identified and cloned into a vector in front of the GUS reporter gene. Both promoters were shown to be functionally active in wheat in both transient assays and in stably transformed wheat plants. Analysis of the stable transformants of wheat (cv. Cadenza) showed that both promoters controlled gus expression throughout leaf development as well as in other green tissues. The availability of these promoters provides new tools for the expression of genes in transgenic wheat leaves and also paves the way for multigene manipulation of photosynthesis to improve yields.
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Affiliation(s)
- Saqer S Alotaibi
- School of Biological Sciences, Wivenhoe Park, University of Essex, Colchester CO4 3SQ, UK.
- Biotechnology Department, Biological Sciences College, Taif University, At Taif 26571, Saudi Arabia.
| | - Caroline A Sparks
- Rothamsted Research, West Common, Harpenden, Hertfordshire AL5 2JQ, UK.
| | - Martin A J Parry
- Rothamsted Research, West Common, Harpenden, Hertfordshire AL5 2JQ, UK.
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK.
| | - Andrew J Simkin
- School of Biological Sciences, Wivenhoe Park, University of Essex, Colchester CO4 3SQ, UK.
- Genetics, Genomics and Breeding, NIAB EMR, New Road, East Malling ME19 6BJ, UK.
| | - Christine A Raines
- School of Biological Sciences, Wivenhoe Park, University of Essex, Colchester CO4 3SQ, UK.
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10
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Geldreich A, Haas G, Kubina J, Bouton C, Tanguy M, Erhardt M, Keller M, Ryabova L, Dimitrova M. Formation of large viroplasms and virulence of Cauliflower mosaic virus in turnip plants depend on the N-terminal EKI sequence of viral protein TAV. PLoS One 2017; 12:e0189062. [PMID: 29253877 PMCID: PMC5734791 DOI: 10.1371/journal.pone.0189062] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 11/17/2017] [Indexed: 12/11/2022] Open
Abstract
Cauliflower mosaic virus (CaMV) TAV protein (TransActivator/Viroplasmin) plays a pivotal role during the infection cycle since it activates translation reinitiation of viral polycistronic RNAs and suppresses RNA silencing. It is also the major component of cytoplasmic electron-dense inclusion bodies (EDIBs) called viroplasms that are particularly evident in cells infected by the virulent CaMV Cabb B-JI isolate. These EDIBs are considered as virion factories, vehicles for CaMV intracellular movement and reservoirs for CaMV transmission by aphids. In this study, focused on different TAV mutants in vivo, we demonstrate that three physically separated domains collectively participate to the formation of large EDIBs: the N-terminal EKI motif, a sequence of the MAV domain involved in translation reinitiation and a C-terminal region encompassing the zinc finger. Surprisingly, EKI mutant TAVm3, corresponding to a substitution of the EKI motif at amino acids 11-13 by three alanines (AAA), which completely abolished the formation of large viroplasms, was not lethal for CaMV but highly reduced its virulence without affecting the rate of systemic infection. Expression of TAVm3 in a viral context led to formation of small irregularly shaped inclusion bodies, mild symptoms and low levels of viral DNA and particles accumulation, despite the production of significant amounts of mature capsid proteins. Unexpectedly, for CaMV-TAVm3 the formation of viral P2-containing electron-light inclusion body (ELIB), which is essential for CaMV aphid transmission, was also altered, thus suggesting an indirect role of the EKI tripeptide in CaMV plant-to-plant propagation. This important functional contribution of the EKI motif in CaMV biology can explain the strict conservation of this motif in the TAV sequences of all CaMV isolates.
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Affiliation(s)
- Angèle Geldreich
- Institut de Biologie Moléculaire des Plantes, CNRS UPR2357, Université de Strasbourg, Strasbourg, France
| | - Gabrielle Haas
- Institut de Biologie Moléculaire des Plantes, CNRS UPR2357, Université de Strasbourg, Strasbourg, France
| | - Julie Kubina
- Institut de Biologie Moléculaire des Plantes, CNRS UPR2357, Université de Strasbourg, Strasbourg, France
| | - Clément Bouton
- Institut de Biologie Moléculaire des Plantes, CNRS UPR2357, Université de Strasbourg, Strasbourg, France
| | - Mélanie Tanguy
- Institut de Biologie Moléculaire des Plantes, CNRS UPR2357, Université de Strasbourg, Strasbourg, France
| | - Mathieu Erhardt
- Institut de Biologie Moléculaire des Plantes, CNRS UPR2357, Université de Strasbourg, Strasbourg, France
| | - Mario Keller
- Institut de Biologie Moléculaire des Plantes, CNRS UPR2357, Université de Strasbourg, Strasbourg, France
| | - Lyubov Ryabova
- Institut de Biologie Moléculaire des Plantes, CNRS UPR2357, Université de Strasbourg, Strasbourg, France
| | - Maria Dimitrova
- Institut de Biologie Moléculaire des Plantes, CNRS UPR2357, Université de Strasbourg, Strasbourg, France
- * E-mail:
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11
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Exposito-Rodriguez M, Laissue PP, López-Calcagno PE, Mullineaux PM, Raines CA, Simkin AJ. Development of pGEMINI, a Plant Gateway Destination Vector Allowing the Simultaneous Integration of Two cDNA via a Single LR-Clonase Reaction. PLANTS 2017; 6:plants6040055. [PMID: 29137147 PMCID: PMC5750631 DOI: 10.3390/plants6040055] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 11/06/2017] [Accepted: 11/10/2017] [Indexed: 01/11/2023]
Abstract
Gateway technology has been used to facilitate the generation of a large number of constructs for the modification of plants for research purposes. However, many of the currently available vectors only allow the integration of a single cDNA of interest into an expression clone. The ability to over-express multiple genes in combination is essential for the study of plant development where several transcripts have a role to play in one or more metabolic processes. The tools to carry out such studies are limited, and in many cases rely on the incorporation of cDNA into expression systems via conventional cloning, which can be both time consuming and laborious. To our knowledge, this study reports on the first development of a vector allowing the simultaneous integration of two independent cDNAs via a single LR-clonase reaction. This vector “pGEMINI” represents a powerful molecular tool offering the ability to study the role of multi-cDNA constructs on plant development, and opens up the process of gene stacking and the study of gene combinations through transient or stable transformation procedures.
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Affiliation(s)
| | - Philippe P Laissue
- School of Biological Sciences, Wivenhoe Park, University of Essex, Colchester CO4 3SQ, UK.
| | | | - Philip M Mullineaux
- School of Biological Sciences, Wivenhoe Park, University of Essex, Colchester CO4 3SQ, UK.
| | - Christine A Raines
- School of Biological Sciences, Wivenhoe Park, University of Essex, Colchester CO4 3SQ, UK.
| | - Andrew J Simkin
- Genetics, Genomics and Breeding, NIAB EMR, New Road, East Malling, Kent ME19 6BJ, UK.
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12
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Complete genome sequence of a putative new caulimovirus which exists as endogenous pararetroviral sequences in Angelica dahurica. Arch Virol 2017; 162:3837-3842. [PMID: 28812199 DOI: 10.1007/s00705-017-3517-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 07/09/2017] [Indexed: 10/19/2022]
Abstract
A virus isolate designated Angelica bushy stunt virus (AnBSV), provisionally representing a new species in the genus Caulimovirus, was discovered in the medicinal plant Angelica dahurica. The complete 8,300-nt genomic DNA of AnBSV had seven putative open reading frames containing conserved domains/motifs, which are typical features of caulimoviruses, and showed the greatest nucleotide sequence identity (74% identity and 27% query coverage) to a lamium leaf distortion virus isolate. Interestingly, the new caulimovirus exists as endogenous pararetroviral sequences in the host plant and is considered to have multiple defective plant genome-integrated copies that may lead to the generation of subgenomic DNA species.
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13
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Moreira F, Carneiro J, Pereira F. A proposal for standardization of transgenic reference sequences used in food forensics. Forensic Sci Int Genet 2017; 29:e26-e28. [PMID: 28506735 DOI: 10.1016/j.fsigen.2017.04.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 04/30/2017] [Indexed: 10/19/2022]
Affiliation(s)
- Filipa Moreira
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), University of Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208, Matosinhos, Portugal.
| | - João Carneiro
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), University of Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208, Matosinhos, Portugal.
| | - Filipe Pereira
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), University of Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208, Matosinhos, Portugal.
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14
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Vilperte V, Agapito-Tenfen SZ, Wikmark OG, Nodari RO. Levels of DNA methylation and transcript accumulation in leaves of transgenic maize varieties. ENVIRONMENTAL SCIENCES EUROPE 2016; 28:29. [PMID: 27942424 PMCID: PMC5120055 DOI: 10.1186/s12302-016-0097-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 11/15/2016] [Indexed: 05/26/2023]
Abstract
BACKGROUND Prior to their release in the environment, transgenic crops are examined for their health and environmental safety. In addition, transgene expression needs to be consistent in order to express the introduced trait (e.g. insecticidal and/or herbicide tolerance). Moreover, data on expression levels for GM events are usually required for approval, but these are rarely disclosed or they are considered insufficient. On the other hand, biosafety regulators do not consider epigenetic regulation (e.g. DNA methylation, ncRNAs and histone modifications), which are broadly known to affect gene expression, within their risk assessment analyses. Here we report the results of a DNA methylation (bisulfite sequencing) and transgene transcript accumulation (RT-qPCR) analysis of four Bt-expressing single transgenic maize hybrids, under different genetic backgrounds, and a stacked transgenic hybrid expressing both insecticidal and herbicide tolerance traits. RESULTS Our results showed differences in cytosine methylation levels in the FMV promoter and cry2Ab2 transgene of the four Bt-expressing hybrid varieties. The comparison between single and stacked hybrids under the same genetic background showed differences in the 35S promoter sequence. The results of transgene transcript accumulation levels showed differences in both cry1A.105 and cry2Ab2 transgenes among the four Bt-expressing hybrid varieties. The comparison between single and stacked hybrids showed difference for the cry2Ab2 transgene only. CONCLUSIONS Overall, our results show differences in DNA methylation patterns in all varieties, as well as in transgene transcript accumulation levels. Although the detection of changes in DNA methylation and transgenic accumulation levels does not present a safety issue per se, it demonstrates the need for additional studies that focus on detecting possible safety implications of such changes.
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Affiliation(s)
- Vinicius Vilperte
- Department of Crop Science, Federal University of Santa Catarina, Florianópolis, Santa Catarina Brazil
- GenØk - Centre for Biosafety, Tromsø, Norway
- Institute for Plant Genetics, Faculty of Natural Sciences, Leibniz University of Hannover, Hannover, Germany
| | | | - Odd-Gunnar Wikmark
- GenØk - Centre for Biosafety, Tromsø, Norway
- Unit for Environmental Science and Management, Potchefstroom Campus, North West University, Potchefstroom, South Africa
| | - Rubens Onofre Nodari
- Department of Crop Science, Federal University of Santa Catarina, Florianópolis, Santa Catarina Brazil
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15
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Lim S, Igori D, Zhao F, Yoo RH, An TJ, Lim HS, Lee SH, Moon JS. Complete genome sequence of a tentative new caulimovirus from the medicinal plant Atractylodes macrocephala. Arch Virol 2015; 160:3127-31. [DOI: 10.1007/s00705-015-2576-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 08/18/2015] [Indexed: 11/29/2022]
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16
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Simkin AJ, McAusland L, Headland LR, Lawson T, Raines CA. Multigene manipulation of photosynthetic carbon assimilation increases CO2 fixation and biomass yield in tobacco. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:4075-90. [PMID: 25956882 PMCID: PMC4473996 DOI: 10.1093/jxb/erv204] [Citation(s) in RCA: 137] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Over the next 40 years it has been estimated that a 50% increase in the yield of grain crops such as wheat and rice will be required to meet the food and fuel demands of the increasing world population. Transgenic tobacco plants have been generated with altered combinations of sedoheptulose-1,7-bisphosphatase, fructose-1,6-bisphosphate aldolase, and the cyanobacterial putative-inorganic carbon transporter B, ictB, of which have all been identified as targets to improve photosynthesis based on empirical studies. It is shown here that increasing the levels of the three proteins individually significantly increases the rate of photosynthetic carbon assimilation, leaf area, and biomass yield. Furthermore, the daily integrated measurements of photosynthesis showed that mature plants fixed between 12-19% more CO2 than the equivalent wild-type plants. Further enhancement of photosynthesis and yield was observed when sedoheptulose-1,7-bisphosphatase, fructose-1,6-bisphosphate aldolase, and ictB were over-expressed together in the same plant. These results demonstrate the potential for the manipulation of photosynthesis, using multigene-stacking approaches, to increase crop yields.
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Affiliation(s)
- Andrew J Simkin
- School of Biological Sciences, Wivenhoe Park, University of Essex, Colchester CO4 3SQ, UK
| | - Lorna McAusland
- School of Biological Sciences, Wivenhoe Park, University of Essex, Colchester CO4 3SQ, UK
| | - Lauren R Headland
- School of Biological Sciences, Wivenhoe Park, University of Essex, Colchester CO4 3SQ, UK
| | - Tracy Lawson
- School of Biological Sciences, Wivenhoe Park, University of Essex, Colchester CO4 3SQ, UK
| | - Christine A Raines
- School of Biological Sciences, Wivenhoe Park, University of Essex, Colchester CO4 3SQ, UK
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17
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Villacreses J, Rojas-Herrera M, Sánchez C, Hewstone N, Undurraga SF, Alzate JF, Manque P, Maracaja-Coutinho V, Polanco V. Deep sequencing reveals the complete genome and evidence for transcriptional activity of the first virus-like sequences identified in Aristotelia chilensis (Maqui Berry). Viruses 2015; 7:1685-99. [PMID: 25855242 PMCID: PMC4411674 DOI: 10.3390/v7041685] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 03/12/2015] [Accepted: 03/25/2015] [Indexed: 01/01/2023] Open
Abstract
Here, we report the genome sequence and evidence for transcriptional activity of a virus-like element in the native Chilean berry tree Aristotelia chilensis. We propose to name the endogenous sequence as Aristotelia chilensis Virus 1 (AcV1). High-throughput sequencing of the genome of this tree uncovered an endogenous viral element, with a size of 7122 bp, corresponding to the complete genome of AcV1. Its sequence contains three open reading frames (ORFs): ORFs 1 and 2 shares 66%–73% amino acid similarity with members of the Caulimoviridae virus family, especially the Petunia vein clearing virus (PVCV), Petuvirus genus. ORF1 encodes a movement protein (MP); ORF2 a Reverse Transcriptase (RT) and a Ribonuclease H (RNase H) domain; and ORF3 showed no amino acid sequence similarity with any other known virus proteins. Analogous to other known endogenous pararetrovirus sequences (EPRVs), AcV1 is integrated in the genome of Maqui Berry and showed low viral transcriptional activity, which was detected by deep sequencing technology (DNA and RNA-seq). Phylogenetic analysis of AcV1 and other pararetroviruses revealed a closer resemblance with Petuvirus. Overall, our data suggests that AcV1 could be a new member of Caulimoviridae family, genus Petuvirus, and the first evidence of this kind of virus in a fruit plant.
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Affiliation(s)
- Javier Villacreses
- Centro de Genómica y Bioinformática, Facultad de Ciencias, Universidad Mayor, Santiago 8580000, Chile.
| | - Marcelo Rojas-Herrera
- Centro de Genómica y Bioinformática, Facultad de Ciencias, Universidad Mayor, Santiago 8580000, Chile.
| | - Carolina Sánchez
- Centro de Genómica y Bioinformática, Facultad de Ciencias, Universidad Mayor, Santiago 8580000, Chile.
| | | | - Soledad F Undurraga
- Centro de Genómica y Bioinformática, Facultad de Ciencias, Universidad Mayor, Santiago 8580000, Chile.
| | - Juan F Alzate
- Centro Nacional de Secuenciación Genómica, Universidad de Antioquia, Medellín, Colombia.
| | - Patricio Manque
- Centro de Genómica y Bioinformática, Facultad de Ciencias, Universidad Mayor, Santiago 8580000, Chile.
| | | | - Victor Polanco
- Centro de Genómica y Bioinformática, Facultad de Ciencias, Universidad Mayor, Santiago 8580000, Chile.
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18
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Almeyda CV, Eid SG, Saar D, Samuitiene M, Pappu HR. Comparative analysis of endogenous plant pararetroviruses in cultivated and wild Dahlia spp. Virus Genes 2013; 48:140-52. [PMID: 24353027 DOI: 10.1007/s11262-013-0997-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 10/16/2013] [Indexed: 11/28/2022]
Abstract
Two distinct caulimoviruses, Dahlia mosaic virus (DMV) and Dahlia common mosaic virus, and an endogenous plant pararetroviral sequence (DvEPRS) were reported in Dahlia spp. DvEPRS, previously referred to as DMV-D10, was originally identified in the US from the cultivated Dahlia variabilis, and has also been found in New Zealand, Lithuania and Egypt, as well as in wild dahlia species growing in their natural habitats in Mexico. Sequence analysis of three new EPRSs from cultivated dahlias from Lithuania [D10-LT; 7,159 nucleotide level (nt)], New Zealand (D10-NZ, 7,156 nt), and the wild species, Dahlia rupicola, from Mexico (D10-DR, 7,133 nt) is reported in this study. The three EPRSs have the structure and organization typical of a caulimovirus species and showed identities among various open reading frames (ORFs) ranging between 71 and 97 % at the nt when compared to those or the known DvEPRS from the US. Examination of a dataset of seven full-length EPRSs obtained to date from cultivated and wild Dahlia spp. provided clues into genetic diversity of these EPRSs from diverse sources of dahlia. Phylogenetic analyses, mutation frequencies, potential recombination events, selection, and fitness were evaluated as evolutionary evidences for genetic variation. Assessment of all ORFs using phylogenomic and population genetics approaches suggests a wide genetic diversity of EPRSs occurring in dahlias. Phylogenetic analyses show that the EPRSs from various sources form one clade indicating a lack of clustering by geographical origin. Grouping of various EPRSs into two host taxa (cultivated vs. wild) shows little divergence with respect to their origin. Population genetic parameters demonstrate negative selection for all ORFs, with the reverse transcriptase region more variable than other ORFs. Recombination events were found which provide evolutionary evidence for genetic diversity among dahlia-associated EPRSs. This study contributes to an increased understanding of molecular population genetics and evolutionary pathways of these reverse transcribing viral elements.
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Affiliation(s)
- C V Almeyda
- Department of Plant Pathology, Washington State University, Pullman, WA, 99164, USA
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19
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Patro S, Maiti IB, Dey N. Development of an efficient bi-directional promoter with tripartite enhancer employing three viral promoters. J Biotechnol 2013; 163:311-7. [PMID: 23183382 DOI: 10.1016/j.jbiotec.2012.11.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Revised: 11/15/2012] [Accepted: 11/16/2012] [Indexed: 10/27/2022]
Abstract
We have developed a novel bi-directional promoter (FsFfCBD) by placing two heterogeneous core-promoters from the Figwort mosaic virus sub-genomic transcript promoter (FsCP, -69 to +31) and Cauliflower mosaic virus 35S promoter (CCP, -89 to +1) respectively on upstream (5') and downstream (3') ends of a tri-hybrid enhancer (FsEFfECE), in reverse orientation. The FsEFfECE domain encompasses three heterologous enhancer fragments from Figwort mosaic virus sub-genomic transcript promoter (FsE, 101 bp, -70 to -170), Figwort mosaic virus full-length transcript promoter (FfE, 196 bp, -249 to -54) and Cauliflower mosaic virus 35S promoter (CE, 254 bp, -343 to -90). The bi-directional nature of the FsFfCBD promoter (coupled to GFP and GUS) was established both in transient systems (onion epidermal cells and tobacco protoplasts) and transgenic plant (Nicotiana tabacum samsun NN) by monitoring the simultaneous expression of GFP and GUS employing fluorescence (for GFP) and biochemical (for GUS) based assays. In transgenic plants, the FsFfCBD promoter was found to be 6.8 and 2.5 times stronger than two parent promoters; Fs and FfC respectively. The bi-directional compound promoter FsFfCBD, composed of three heterologous enhancers with enhanced activity could become a valuable additional tool for efficient plant metabolic engineering and molecular pharming.
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Affiliation(s)
- Sunita Patro
- Division of Gene Function and Regulation, Institute of Life Sciences, Department of Biotechnology, Govt. of India, Nalco Square, Chandrasekherpur, Bhubaneswar 751 023, Odisha, India
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20
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Real-time PCR method for the detection of figwort mosaic virus (FMV) to complement the FMV 34S promoter-specific PCR assay used for screening of genetically modified plants. Eur Food Res Technol 2012. [DOI: 10.1007/s00217-012-1811-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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21
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Kumar D, Patro S, Ghosh J, Das A, Maiti IB, Dey N. Development of a salicylic acid inducible minimal sub-genomic transcript promoter from Figwort mosaic virus with enhanced root- and leaf-activity using TGACG motif rearrangement. Gene 2012; 503:36-47. [PMID: 22561698 DOI: 10.1016/j.gene.2012.04.053] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Revised: 04/14/2012] [Accepted: 04/18/2012] [Indexed: 11/24/2022]
Abstract
In Figwort mosaic virus sub-genomic transcript promoter (F-Sgt), function of the TGACG-regulatory motif, was investigated in the background of artificially designed promoter sequences. The 131bp (FS, -100 to +31) long F-Sgt promoter sequence containing one TGACG motif [FS-(TGACG)] was engineered to generate a set of three modified promoter constructs: [FS-(TGACG)(2), containing one additional TGACG motif at 7 nucleotides upstream of the original one], [FS-(TGACG)(3), containing two additional TGACG motifs at 7 nucleotides upstream and two nucleotides downstream of the original one] and [FS-(TGCTG)(mu), having a mutated TGACG motif]. EMSA and foot-printing analysis confirmed binding of tobacco nuclear factors with modified TGACG motif/s. The transcription-activation of the GUS gene by the TGACG motif/s in above promoter constructs was examined in transgenic tobacco and Arabidopsis plants and observed that the transcription activation was affected by the spacing/s and number/s of the TGACG motif/s. The FS-(TGACG)(2) promoter showed strongest root-activity compared to other modified and CaMV35S promoters. Also under salicylic acid (SA) stress, the leaf-activity of the said promoter was further enhanced. All above findings were confirmed by real-time and semi-qRT PCR analysis. Taken together, these results clearly demonstrated that the TGACG motif plays an important role in inducing the root-specific expression of the F-Sgt promoter. This study advocates the importance of genetic manipulation of functional cis-motif for amending the tissue specificity of a plant promoter. SA inducible FS-(TGACG)(2) promoter with enhanced activity could be a useful candidate promoter for developing plants with enhanced crop productivity.
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Affiliation(s)
- Deepak Kumar
- Department of Gene Function and Regulation, Institute of Life Sciences, Government of India, Chandrasekherpur, Orissa, India.
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22
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Tieman D, Bliss P, McIntyre L, Blandon-Ubeda A, Bies D, Odabasi A, Rodríguez G, van der Knaap E, Taylor M, Goulet C, Mageroy M, Snyder D, Colquhoun T, Moskowitz H, Clark D, Sims C, Bartoshuk L, Klee H. The Chemical Interactions Underlying Tomato Flavor Preferences. Curr Biol 2012; 22:1035-9. [DOI: 10.1016/j.cub.2012.04.016] [Citation(s) in RCA: 189] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Revised: 04/11/2012] [Accepted: 04/11/2012] [Indexed: 10/28/2022]
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23
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Mageroy MH, Tieman DM, Floystad A, Taylor MG, Klee HJ. A Solanum lycopersicum catechol-O-methyltransferase involved in synthesis of the flavor molecule guaiacol. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 69:1043-51. [PMID: 22103597 DOI: 10.1111/j.1365-313x.2011.04854.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
O-methyltransferases (OMT) are important enzymes that are responsible for the synthesis of many small molecules, which include lignin monomers, flavonoids, alkaloids, and aroma compounds. One such compound is guaiacol, a small volatile molecule with a smoky aroma that contributes to tomato flavor. Little information is known about the pathway and regulation of synthesis of guaiacol. One possible route for synthesis is via catechol methylation. We identified a tomato O-methyltransferase (CTOMT1) with homology to a Nicotiana tabacum catechol OMT. CTOMT1 was cloned from Solanum lycopersicum cv. M82 and expressed in Escherichia coli. Recombinant CTOMT1 enzyme preferentially methylated catechol, producing guaiacol. To validate the in vivo function of CTOMT1, gene expression was either decreased or increased in transgenic S. lycopersicum plants. Knockdown of CTOMT1 resulted in significantly reduced fruit guaiacol emissions. CTOMT1 overexpression resulted in slightly increased fruit guaiacol emission, which suggested that catechol availability might limit guaiacol production. To test this hypothesis, wild type (WT) and CTOMT1 that overexpress tomato pericarp discs were supplied with exogenously applied catechol. Guaiacol production increased in both WT and transgenic fruit discs, although to a much greater extent in CTOMT1 overexpressing discs. Finally, we identified S. pennellii introgression lines with increased guaiacol content and higher expression of CTOMT1. These lines also showed a trend toward lower catechol levels. Taken together, we concluded that CTOMT1 is a catechol-O-methyltransferase that produces guaiacol in tomato fruit.
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Affiliation(s)
- Melissa H Mageroy
- Plant Molecular and Cellular Biology Program, University of Florida, Gainesville, FL 32611-0690, USA
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24
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Eid S, Almeyda CV, Saar DE, Druffel KL, Pappu HR. Genomic characterization of pararetroviral sequences in wild Dahlia spp. in natural habitats. Arch Virol 2011; 156:2079-84. [DOI: 10.1007/s00705-011-1076-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2011] [Accepted: 07/15/2011] [Indexed: 10/17/2022]
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25
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Cuellar WJ, De Souza J, Barrantes I, Fuentes S, Kreuze JF. Distinct cavemoviruses interact synergistically with sweet potato chlorotic stunt virus (genus Crinivirus) in cultivated sweet potato. J Gen Virol 2011; 92:1233-1243. [PMID: 21307225 DOI: 10.1099/vir.0.029975-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Two serologically unrelated sweet potato viruses causing symptoms of vein clearing in the indicator plant Ipomoea setosa were isolated and their genomes have been sequenced. They are associated with symptomless infections in sweet potato but distinct vein-clearing symptoms and higher virus titres were observed when these viruses co-infected with sweet potato chlorotic stunt virus (SPCSV), a virus that is distributed worldwide and is a mediator of severe virus diseases in this crop. Molecular characterization and phylogenetic analysis revealed an overall nucleotide identity of 47.6 % and an arrangement of the movement protein and coat protein domains characteristic of members of the genus Cavemovirus, in the family Caulimoviridae. We detected both cavemoviruses in cultivated sweet potato from East Africa, Central America and the Caribbean islands, but not in samples from South America. One of the viruses characterized showed a similar genome organization as, and formed a phylogenetic sublineage with, tobacco vein clearing virus (TVCV), giving further support to the previously suggested separation of TVCV, and related viral sequences, into a new caulimovirid genus. Given their geographical distribution and previous reports of similar but yet unidentified viruses, sweet potato cavemoviruses may co-occur with SPCSV more often than previously thought and they could therefore contribute to the extensive yield losses and cultivar decline caused by mixed viral infections in sweet potato.
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Affiliation(s)
- Wilmer J Cuellar
- Virology Laboratory, Crop Management & Production Systems Division, International Potato Center (CIP), Av. La Molina 1895, Lima 12, Peru
| | - Joao De Souza
- Virology Laboratory, Crop Management & Production Systems Division, International Potato Center (CIP), Av. La Molina 1895, Lima 12, Peru
| | - Israel Barrantes
- Magdeburg Centre for Systems Biology (MaCS), Otto von Guericke University, Sandtorstr. 1, D-39106 Magdeburg, Germany
| | - Segundo Fuentes
- Virology Laboratory, Crop Management & Production Systems Division, International Potato Center (CIP), Av. La Molina 1895, Lima 12, Peru
| | - Jan F Kreuze
- Applied Biotechnology Laboratory, Germplasm Enhancement & Crop Improvement Division, International Potato Center (CIP), Av. La Molina 1895, Lima 12, Peru
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26
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Akhtar TA, Orsomando G, Mehrshahi P, Lara-Núñez A, Bennett MJ, Gregory JF, Hanson AD. A central role for gamma-glutamyl hydrolases in plant folate homeostasis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 64:256-66. [PMID: 21070406 DOI: 10.1111/j.1365-313x.2010.04330.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Most cellular folates carry a short poly-γ-glutamate tail, and this tail is believed to affect their efficacy and stability. The tail can be removed by γ-glutamyl hydrolase (GGH; EC 3.4.19.9), a vacuolar enzyme whose role in folate homeostasis remains unclear. In order to probe the function of GGH, we modulated its level of expression and subcellular location in Arabidopsis plants and tomato fruit. Three-fold overexpression of GGH in vacuoles caused extensive deglutamylation of folate polyglutamates and lowered the total folate content by approximately 40% in Arabidopsis and tomato. No such effects were seen when GGH was overexpressed to a similar extent in the cytosol. Ablation of either of the major Arabidopsis GGH genes (AtGGH1 and AtGGH2) alone did not significantly affect folate status. However, a combination of ablation of one gene plus RNA interference (RNAi)-mediated suppression of the other (which lowered total GGH activity by 99%) increased total folate content by 34%. The excess folate accumulated as polyglutamate derivatives in the vacuole. Taken together, these results suggest a model in which: (i) folates continuously enter the vacuole as polyglutamates, accumulate there, are hydrolyzed by GGH, and exit as monoglutamates; and (ii) GGH consequently has an important influence on polyglutamyl tail length and hence on folate stability and cellular folate content.
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Affiliation(s)
- Tariq A Akhtar
- Horticultural Sciences Department, University of Florida, Gainesville, FL 32611, USA.
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27
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Maloney GS, Kochevenko A, Tieman DM, Tohge T, Krieger U, Zamir D, Taylor MG, Fernie AR, Klee HJ. Characterization of the branched-chain amino acid aminotransferase enzyme family in tomato. PLANT PHYSIOLOGY 2010; 153:925-36. [PMID: 20435740 PMCID: PMC2899903 DOI: 10.1104/pp.110.154922] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Accepted: 04/30/2010] [Indexed: 05/18/2023]
Abstract
Branched-chain amino acids (BCAAs) are synthesized in plants from branched-chain keto acids, but their metabolism is not completely understood. The interface of BCAA metabolism lies with branched-chain aminotransferases (BCAT) that catalyze both the last anabolic step and the first catabolic step. In this study, six BCAT genes from the cultivated tomato (Solanum lycopersicum) were identified and characterized. SlBCAT1, -2, -3, and -4 are expressed in multiple plant tissues, while SlBCAT5 and -6 were undetectable. SlBCAT1 and -2 are located in the mitochondria, SlBCAT3 and -4 are located in chloroplasts, while SlBCAT5 and -6 are located in the cytosol and vacuole, respectively. SlBCAT1, -2, -3, and -4 were able to restore growth of Escherichia coli BCAA auxotrophic cells, but SlBCAT1 and -2 were less effective than SlBCAT3 and -4 in growth restoration. All enzymes were active in the forward (BCAA synthesis) and reverse (branched-chain keto acid synthesis) reactions. SlBCAT3 and -4 exhibited a preference for the forward reaction, while SlBCAT1 and -2 were more active in the reverse reaction. While overexpression of SlBCAT1 or -3 in tomato fruit did not significantly alter amino acid levels, an expression quantitative trait locus on chromosome 3, associated with substantially higher expression of Solanum pennellii BCAT4, did significantly increase BCAA levels. Conversely, antisense-mediated reduction of SlBCAT1 resulted in higher levels of BCAAs. Together, these results support a model in which the mitochondrial SlBCAT1 and -2 function in BCAA catabolism while the chloroplastic SlBCAT3 and -4 function in BCAA synthesis.
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MESH Headings
- Amino Acids, Branched-Chain/biosynthesis
- Amino Acids, Branched-Chain/chemistry
- Biosynthetic Pathways
- Chromatography, High Pressure Liquid
- Cloning, Molecular
- DNA, Complementary/genetics
- Escherichia coli/growth & development
- Gene Expression Profiling
- Gene Expression Regulation, Enzymologic
- Gene Expression Regulation, Plant
- Genetic Complementation Test
- Inbreeding
- Kinetics
- Solanum lycopersicum/enzymology
- Solanum lycopersicum/genetics
- Multigene Family
- Organ Specificity/genetics
- Physical Chromosome Mapping
- Plants, Genetically Modified
- Protein Transport
- Quantitative Trait Loci/genetics
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Reproducibility of Results
- Sequence Homology, Amino Acid
- Subcellular Fractions/enzymology
- Transaminases/genetics
- Transaminases/metabolism
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28
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Tieman D, Zeigler M, Schmelz E, Taylor MG, Rushing S, Jones JB, Klee HJ. Functional analysis of a tomato salicylic acid methyl transferase and its role in synthesis of the flavor volatile methyl salicylate. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 62:113-23. [PMID: 20070566 DOI: 10.1111/j.1365-313x.2010.04128.x] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Methyl salicylate (MeSA) is a volatile plant secondary metabolite that is an important contributor to taste and scent of many fruits and flowers. It is synthesized from salicylic acid (SA), a phytohormone that contributes to plant pathogen defense. MeSA is synthesized by members of a family of O-methyltransferases. In order to elaborate the mechanism of MeSA synthesis in tomato, we screened a set of O-methyltransferases for activity against multiple substrates. An enzyme that specifically catalyzes methylation of SA, SlSAMT, as well as enzymes that act upon jasmonic acid and indole-3-acetic acid were identified. Analyses of transgenic over- and under-producing lines validated the function of SlSAMT in vivo. The SlSAMT gene was mapped to a position near the bottom of chromosome 9. Analysis of MeSA emissions from an introgression population derived from a cross with Solanum pennellii revealed a quantitative trait locus (QTL) linked to higher fruit methyl salicylate emissions. The higher MeSA emissions associate with significantly higher SpSAMT expression, consistent with SAMT gene expression being rate limiting for ripening-associated MeSA emissions. Transgenic plants that constitutively over-produce MeSA exhibited only slightly delayed symptom development following infection with the disease-causing bacterial pathogen, Xanthomonas campestris pv. vesicatoria (Xcv). Unexpectedly, pathogen-challenged leaves accumulated significantly higher levels of SA as well as glycosylated forms of SA and MeSA, indicating a disruption in control of the SA-related metabolite pool. Taken together, the results indicate that SlSAMT is critical for methyl salicylate synthesis and methyl salicylate, in turn, likely has an important role in controlling SA synthesis.
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Affiliation(s)
- Denise Tieman
- Plant Molecular and Cellular Biology Program, Horticultural Sciences, University of Florida, Gainesville, FL 32611-0690, USA
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Vogel JT, Walter MH, Giavalisco P, Lytovchenko A, Kohlen W, Charnikhova T, Simkin AJ, Goulet C, Strack D, Bouwmeester HJ, Fernie AR, Klee HJ. SlCCD7 controls strigolactone biosynthesis, shoot branching and mycorrhiza-induced apocarotenoid formation in tomato. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 61:300-11. [PMID: 19845881 DOI: 10.1111/j.1365-313x.2009.04056.x] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The regulation of shoot branching is an essential determinant of plant architecture, integrating multiple external and internal signals. One of the signaling pathways regulating branching involves the MAX (more axillary branches) genes. Two of the genes within this pathway, MAX3/CCD7 and MAX4/CCD8, encode carotenoid cleavage enzymes involved in generating a branch-inhibiting hormone, recently identified as strigolactone. Here, we report the cloning of SlCCD7 from tomato. As in other species, SlCCD7 encodes an enzyme capable of cleaving cyclic and acyclic carotenoids. However, the SlCCD7 protein has 30 additional amino acids of unknown function at its C terminus. Tomato plants expressing a SlCCD7 antisense construct display greatly increased branching. To reveal the underlying changes of this strong physiological phenotype, a metabolomic screen was conducted. With the exception of a reduction of stem amino acid content in the transgenic lines, no major changes were observed. In contrast, targeted analysis of the same plants revealed significantly decreased levels of strigolactone. There were no significant changes in root carotenoids, indicating that relatively little substrate is required to produce the bioactive strigolactones. The germination rate of Orobanche ramosa seeds was reduced by up to 90% on application of extract from the SlCCD7 antisense lines, compared with the wild type. Additionally, upon mycorrhizal colonization, C(13) cyclohexenone and C(14) mycorradicin apocarotenoid levels were greatly reduced in the roots of the antisense lines, implicating SlCCD7 in their biosynthesis. This work demonstrates the diverse roles of MAX3/CCD7 in strigolactone production, shoot branching, source-sink interactions and production of arbuscular mycorrhiza-induced apocarotenoids.
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Affiliation(s)
- Jonathan T Vogel
- Horticultural Sciences Department and the Plant Molecular & Cellular Biology Program, University of Florida, Gainesville, Florida 32611, USA
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Dietz-Pfeilstetter A, Zwerger P. In-field frequencies and characteristics of oilseed rape with double herbicide resistance. ENVIRONMENTAL BIOSAFETY RESEARCH 2009; 8:101-11. [PMID: 19833077 DOI: 10.1051/ebr/2009006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
When growing different transgenic herbicide-resistant oilseed rape cultivars side by side, seeds with multiple herbicide resistance can arise, possibly causing problems for the management of volunteer plants. Large-scale field experiments were performed in the years 1999/2000 and 2000/2001 in order to investigate the frequencies and the consequences of the transfer of herbicide resistance genes from transgenic oilseed rape to cultivars grown on neighboring agricultural fields. Transgenic oilseed rape with resistance to glufosinate-ammonium (LibertyLink, LL) and with glyphosate resistance (RoundupReady, RR), respectively, was sown in adjacent 0.5 ha plots, surrounded by about 8 ha non-transgenic oilseed rape. The plots and the field were either in direct contact (0.5 m gap width) or they were separated by 10 m of fallow land. Seed samples taken during harvest in the transgenic plots at different distances were investigated for progeny with resistance to the respective other herbicide. It was found that outcrossing frequencies were reduced to different extents by a 10 m isolation distance. In addition to pollen-mediated transgene flow as a result of outcrossing, we found considerable seed-mediated gene flow by adventitious dispersal of transgenic seeds through the harvesting machine. Volunteer plants with double herbicide resistance emerging in the transgenic plots after harvest were selected by suitable applications of the complementary herbicides Basta and Roundup Ultra. In both years, double-resistant volunteers were largely restricted to the inner edges of the plots. Expression analysis under controlled laboratory conditions of double-resistant plants generated by manual crosses revealed stability of transgene expression even at elevated temperatures. Greenhouse tests with double-resistant oilseed rape plants gave no indication that the sensitivity to a range of different herbicides is changed as compared to non-transgenic oilseed rape.
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Affiliation(s)
- Antje Dietz-Pfeilstetter
- Institute for Biosafety of Genetically Modified Plants and Institute for Plant Protection in Field Crops and Grassland, Julius Kühn-Institut, Federal Research Centre for Cultivated Plants, Braunschweig, Germany.
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Dexter RJ, Verdonk JC, Underwood BA, Shibuya K, Schmelz EA, Clark DG. Tissue-specific PhBPBT expression is differentially regulated in response to endogenous ethylene. JOURNAL OF EXPERIMENTAL BOTANY 2008; 59:609-618. [PMID: 18256048 DOI: 10.1093/jxb/erm337] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Ethylene is a gaseous plant hormone involved in many physiological processes including senescence, fruit ripening, and defence. Here the effects of pollination and wound-induced ethylene signals on transcript accumulation of benzoyl CoA:benzyl alcohol/phenylethanol benzoyltransferase (PhBPBT) are shown in Petuniaxhybrida cv. Mitchell 'Diploid' (MD). In petunia, PhBPBT is responsible for the biosynthesis of both benzyl benzoate and phenylethyl benzoate from benzyl alcohol and phenylethanol, respectively. RNAi-silenced lines, with reduced PhBPBT transcript, displayed reduced benzyl benzoate emission, and increased benzyl alcohol levels. Detailed expression analysis showed that PhBPBT is regulated by both light and an endogenous circadian rhythm, while it is also differentially regulated in response to ethylene in a tissue-specific manner. Twenty-four hours following pollination of MD flowers, expression of PhBPBT decreases in the corolla, while it increases in the ovary after 48 h. This is caused by ethylene that is emitted from the flower coinciding with fertilization as this is not observed in transgenic ethylene-insensitive plants (CaMV35S::etr1-1; 44568). Ethylene is also emitted from vegetative tissue of petunia following mechanical wounding, resulting in an increase in PhBPBT expression in the leaves where expression is normally below detection levels. Indicative of this pattern of expression, we hypothesize that PhBPBT and subsequent benzyl benzoate production is involved in defence-related processes in the corolla prior to pollination, in the ovary immediately following fertilization, and in vegetative tissue in response to wounding.
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Affiliation(s)
- Richard J Dexter
- Department of Environmental Horticulture, University of Florida, Gainesville, FL 32611, USA
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Kuluev BR, Chemeris AV. Amplification and cloning of dahlia mosaic virus and carnation etched ring virus promoters. RUSS J GENET+ 2007. [DOI: 10.1134/s1022795407120113] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Tieman DM, Loucas HM, Kim JY, Clark DG, Klee HJ. Tomato phenylacetaldehyde reductases catalyze the last step in the synthesis of the aroma volatile 2-phenylethanol. PHYTOCHEMISTRY 2007; 68:2660-9. [PMID: 17644147 DOI: 10.1016/j.phytochem.2007.06.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2007] [Revised: 05/25/2007] [Indexed: 05/16/2023]
Abstract
The volatile compounds, 2-phenylacetaldehyde and 2-phenylethanol, are important for the aroma and flavor of many foods, such as ripe tomato fruits, and are also major constituents of scent of many flowers, most notably roses. While much work has gone into elucidating the pathway for 2-phenylethanol synthesis in bacteria and yeast, the pathways for synthesis in plants are not well characterized. We have identified two tomato enzymes (LePAR1 and LePAR2) that catalyze the conversion of 2-phenylacetaldehyde to 2-phenylethanol: LePAR1, a member of the large and diverse short-chain dehydrogenase/reductase family, strongly prefers 2-phenylacetaldehyde to its shorter and longer homologues (benzaldehyde and cinnamaldehyde, respectively) and does not catalyze the reverse reaction at a measurable rate; LePAR2, however, has similar affinity for 2-phenylacetaldehyde, benzaldehyde and cinnamaldehyde. To confirm the activity of these enzymes in vivo, LePAR1 and LePAR2 cDNAs were individually expressed constitutively in petunia. While wild type petunia flowers emit relatively high levels of 2-phenylacetaldehyde and lower levels of 2-phenylethanol, flowers from the transgenic plants expressing LePAR1 or LePAR2 had significantly higher levels of 2-phenylethanol and lower levels of 2-phenylacetaldehyde. The in vivo alteration of volatile emissions is an important step toward altering aroma volatiles in plants.
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Affiliation(s)
- Denise M Tieman
- Horticultural Sciences Department, University of Florida, Gainesville, FL 32611, United States
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Kevany BM, Tieman DM, Taylor MG, Cin VD, Klee HJ. Ethylene receptor degradation controls the timing of ripening in tomato fruit. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2007; 51:458-67. [PMID: 17655616 DOI: 10.1111/j.1365-313x.2007.03170.x] [Citation(s) in RCA: 158] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Fruit ripening in tomato requires the coordination of both developmental cues and the phytohormone ethylene. The multigene ethylene receptor family has been shown to negatively regulate ethylene signal transduction and suppress ethylene responses. Here we demonstrate that reduction in the levels of either of two family members, LeETR4 or LeETR6, causes an early-ripening phenotype. We provide evidence that the receptors are rapidly degraded in the presence of ethylene, and that degradation probably occurs through the 26S proteasome-dependent pathway. Ethylene exposure of immature fruits causes a reduction in the amount of receptor protein and earlier ripening. The results are consistent with a model in which receptor levels modulate timing of the onset of fruit ripening by measuring cumulative ethylene exposure.
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Affiliation(s)
- Brian M Kevany
- Plant Molecular and Cellular Biology Program, University of Florida, Gainesville, FL 32611-0690, USA
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Dexter R, Qualley A, Kish CM, Ma CJ, Koeduka T, Nagegowda DA, Dudareva N, Pichersky E, Clark D. Characterization of a petunia acetyltransferase involved in the biosynthesis of the floral volatile isoeugenol. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2007; 49:265-75. [PMID: 17241449 DOI: 10.1111/j.1365-313x.2006.02954.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Petunia flower petals emit large amounts of isoeugenol, which has been shown to be synthesized by isoeugenol synthase (PhIGS1) from an ester of coniferyl alcohol, hypothesized to be coniferyl acetate. This paper describes the identification and characterization of a novel petunia gene encoding an enzyme belonging to the BAHD acyltransferase family whose expression correlates with isoeugenol biosynthesis. RNAi suppression of this gene results in inhibition of isoeugenol biosynthesis. Biochemical characterization of the protein encoded by this gene showed that it has acetyltransferase activity and is most efficient with coniferyl alcohol among the alcohol substrates tested. Overall, these data support the conclusion that coniferyl acetate is the substrate of isoeugenol synthase.
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Affiliation(s)
- Richard Dexter
- Department of Environmental Horticulture, University of Florida, Gainesville, FL 32611, USA
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Tieman D, Taylor M, Schauer N, Fernie AR, Hanson AD, Klee HJ. Tomato aromatic amino acid decarboxylases participate in synthesis of the flavor volatiles 2-phenylethanol and 2-phenylacetaldehyde. Proc Natl Acad Sci U S A 2006; 103:8287-92. [PMID: 16698923 PMCID: PMC1472464 DOI: 10.1073/pnas.0602469103] [Citation(s) in RCA: 257] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2006] [Indexed: 11/18/2022] Open
Abstract
An important phenylalanine-derived volatile compound produced by plants is 2-phenylethanol. It is a major contributor to flavor in many foods, including fresh fruits, such as tomato, and an insect-attracting scent in roses and many other flowers. Despite the centrality of 2-phenylethanol to flavor and fragrance, the plant genes responsible for its synthesis have not been identified. Here, we describe a biosynthetic pathway for 2-phenylethanol and other phenylalanine-derived volatiles in tomato fruits and a small family of decarboxylases (LeAADC1A, LeAADC1B, and LeAADC2) that can mediate that pathway's first step. These enzymes each catalyze conversion of phenylalanine to phenethylamine and tyrosine to tyramine. Although tyrosine is the preferred substrate in vitro, phenylalanine levels in tomato fruits far exceed those of tyrosine, indicating that phenylalanine is a physiological substrate. Consistent with this view, overexpression of either LeAADC1A or LeAADC2 in transgenic tomato plants resulted in fruits with up to 10-fold increased emissions of the products of the pathway, including 2-phenylacetaldehyde, 2-phenylethanol, and 1-nitro-2-phenylethane. Further, antisense reduction of LeAADC2 significantly reduced emissions of these volatiles. Besides establishing a biosynthetic route, these results show that it is possible to change phenylalanine-based flavor and aroma volatiles in plants by manipulating expression of a single gene.
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Affiliation(s)
- Denise Tieman
- *Department of Horticultural Sciences, University of Florida, P.O. Box 110690, Gainesville, FL 32611-0690; and
| | - Mark Taylor
- *Department of Horticultural Sciences, University of Florida, P.O. Box 110690, Gainesville, FL 32611-0690; and
| | - Nicolas Schauer
- Max-Planck Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476 Golm-Potsdam, Germany
| | - Alisdair R. Fernie
- Max-Planck Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476 Golm-Potsdam, Germany
| | - Andrew D. Hanson
- *Department of Horticultural Sciences, University of Florida, P.O. Box 110690, Gainesville, FL 32611-0690; and
| | - Harry J. Klee
- *Department of Horticultural Sciences, University of Florida, P.O. Box 110690, Gainesville, FL 32611-0690; and
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Nuñez-Palenius HG, Cantliffe DJ, Huber DJ, Ciardi J, Klee HJ. Transformation of a muskmelon 'Galia' hybrid parental line (Cucumis melo L. var. reticulatus Ser.) with an antisense ACC oxidase gene. PLANT CELL REPORTS 2006; 25:198-205. [PMID: 16362302 DOI: 10.1007/s00299-005-0042-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2005] [Revised: 06/23/2005] [Accepted: 07/09/2005] [Indexed: 05/05/2023]
Abstract
'Galia' muskmelon (Cucumis melo L. var. reticulatus Ser.) has been recalcitrant to transformation by Agrobacterium tumefaciens. Transformation of the 'Galia' male parental line, 'Krymka', with an ACC oxidase (CMACO-1) gene in antisense orientation is described herein. Explants were transformed using A. tumefaciens strain ABI, which contained a vector pCmACO1-AS plasmid, bearing an antisense gene of CMACO-1 and the CP4 syn gene (glyphosate-tolerance). Both CMACO-1 and CP4 syn genes were assessed by a polymerase chain reaction method. Flow cytometry analysis was performed to determine plant ploidy level of primary transformants. Two completely diploid independent transgenic plants were obtained. Southern blot and segregation analysis in the T1 generation determined that each independent transgenic line had one single insertion of the transgene. These transgenic muskmelon male parental lines have potential for use in the production of 'Galia' F1 hybrids with improved shelf life.
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Auldridge ME, Block A, Vogel JT, Dabney-Smith C, Mila I, Bouzayen M, Magallanes-Lundback M, DellaPenna D, McCarty DR, Klee HJ. Characterization of three members of the Arabidopsis carotenoid cleavage dioxygenase family demonstrates the divergent roles of this multifunctional enzyme family. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2006; 45:982-93. [PMID: 16507088 DOI: 10.1111/j.1365-313x.2006.02666.x] [Citation(s) in RCA: 228] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Arabidopsis thaliana has nine genes that constitute a family of putative carotenoid cleavage dioxygenases (CCDs). While five members of the family are believed to be involved in synthesis of the phytohormone abscisic acid, the functions of the other four enzymes are less clear. Recently two of the enzymes, CCD7/MAX3 and CCD8/MAX4, have been implicated in synthesis of a novel apocarotenoid hormone that controls lateral shoot growth. Here, we report on the molecular and genetic interactions between CCD1, CCD7/MAX3 and CCD8/MAX4. CCD1 distinguishes itself from other reported CCDs as being the only member not targeted to the plastid. Unlike ccd7/max3 and ccd8/max4, both characterized as having highly branched phenotypes, ccd1 loss-of-function mutants are indistinguishable from wild-type plants. Thus, even though CCD1 has similar enzymatic activity to CCD7/MAX3, it does not have a role in synthesis of the lateral shoot growth inhibitor. Rather, it may have a role in synthesis of apocarotenoid flavor and aroma volatiles, especially in maturing seeds where loss of function leads to significantly higher carotenoid levels.
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Affiliation(s)
- Michele E Auldridge
- Plant Molecular and Cellular Biology Program, PO Box 110690, University of Florida, Gainesville, FL 32611, USA
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Côté MJ, Meldrum AJ, Raymond P, Dollard C. Identification of genetically modified potato (Solanum tuberosum) cultivars using event specific polymerase chain reaction. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2005; 53:6691-6. [PMID: 16104786 DOI: 10.1021/jf050591i] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Several genetically modified (GM) cultivars are registered in Canada although they are not currently in commercial production. The GM cultivars can be distinguished from the non-GM and other GM cultivars by analyzing the DNA nucleotide sequence at the insertion site of the transgene corresponding to a single transformation event in the plant genome. Techniques based on modified polymerase chain reaction (PCR) strategies were used to generate sequence information from the plant genome flanking the insertion site of transgenic DNA for specific GM potato events. The plant genome sequence adjacent to the transgenic insertion was used to design PCR primers, which could be used in combination with a primer annealing to one of the nearby inserted genetic elements to amplify an event specific DNA fragment. The event specific PCR fragments generated were sequenced to confirm the specificity of the method.
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Affiliation(s)
- Marie-José Côté
- Center for Plant Quarantine Pests, Ottawa Laboratory (Fallowfield), Canadian Food Inspection Agency, 3851 Fallowfield Road, Ottawa, Ontario K2H 8P9, Canada.
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Watanabe T, Kuribara H, Mishima T, Kikuchi H, Kodama T, Futo S, Kasama K, Toyota A, Nouno M, Saita A, Takahashi K, Hino A, Akiyama H, Maitani T, Kubo M. New qualitative detection methods of genetically modified potatoes. Biol Pharm Bull 2005; 27:1333-9. [PMID: 15340215 DOI: 10.1248/bpb.27.1333] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In Japan, 8 lines of genetically modified (GM) potato (2 lines of NewLeaf potato; NL, 3 lines of NewLeaf Plus potato; NLP, and 3 lines of NewLeaf Y potato; NLY) have already been authorized as safe for use in foods and feeds. We have developed polymerase chain reaction (PCR) methods for the qualitative detection of the GM potatoes for the screening and the identification of NL, NLP and NLY. The gene encoding uridine diphosphate (UDP)-glucose pyrophosphorylase (UGPase) was used as a taxon specific gene. We designed the primer pair to detect the cryIIIA genes as a screening method for GM potatoes because the gene should be inserted in all 8 lines of the GM potatoes. For identification of NL, NLP and NLY, we further designed three specific primer pairs for the different recombinant DNAs (r-DNA) specifically introduced into NL, NLP, or NLY. In addition, to identify the 3 lines of NLY that have been introduced with the same r-DNA, the three line-specific primer pairs for the border sequence between the r-DNA and genomic DNA of NLY 3 lines were designed. Six lines of GM potato used as the test material were specifically identified using the each primer pair under the same PCR condition. The detection limits of all the GM potatoes should be approximately 0.1%. Furthermore, the specificity and reproducibility of the methods were confirmed in a six-laboratory collaborative study.
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Affiliation(s)
- Takahiro Watanabe
- National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan.
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Snowden KC, Simkin AJ, Janssen BJ, Templeton KR, Loucas HM, Simons JL, Karunairetnam S, Gleave AP, Clark DG, Klee HJ. The Decreased apical dominance1/Petunia hybrida CAROTENOID CLEAVAGE DIOXYGENASE8 gene affects branch production and plays a role in leaf senescence, root growth, and flower development. THE PLANT CELL 2005; 17:746-59. [PMID: 15705953 PMCID: PMC1069696 DOI: 10.1105/tpc.104.027714] [Citation(s) in RCA: 275] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2004] [Accepted: 12/05/2004] [Indexed: 05/18/2023]
Abstract
Carotenoids and carotenoid cleavage products play an important and integral role in plant development. The Decreased apical dominance1 (Dad1)/PhCCD8 gene of petunia (Petunia hybrida) encodes a hypothetical carotenoid cleavage dioxygenase (CCD) and ortholog of the MORE AXILLARY GROWTH4 (MAX4)/AtCCD8 gene. The dad1-1 mutant allele was inactivated by insertion of an unusual transposon (Dad-one transposon), and the dad1-3 allele is a revertant allele of dad1-1. Consistent with its role in producing a graft-transmissible compound that can alter branching, the Dad1/PhCCD8 gene is expressed in root and shoot tissue. This expression is upregulated in the stems of the dad1-1, dad2, and dad3 increased branching mutants, indicating feedback regulation of the gene in this tissue. However, this feedback regulation does not affect the root expression of Dad1/PhCCD8. Overexpression of Dad1/PhCCD8 in the dad1-1 mutant complemented the mutant phenotype, and RNA interference in the wild type resulted in an increased branching phenotype. Other differences in phenotype associated with the loss of Dad1/PhCCD8 function included altered timing of axillary meristem development, delayed leaf senescence, smaller flowers, reduced internode length, and reduced root growth. These data indicate that the substrate(s) and/or product(s) of the Dad1/PhCCD8 enzyme are mobile signal molecules with diverse roles in plant development.
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Simkin AJ, Schwartz SH, Auldridge M, Taylor MG, Klee HJ. The tomato carotenoid cleavage dioxygenase 1 genes contribute to the formation of the flavor volatiles beta-ionone, pseudoionone, and geranylacetone. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2004; 40:882-92. [PMID: 15584954 DOI: 10.1111/j.1365-313x.2004.02263.x] [Citation(s) in RCA: 275] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Volatile terpenoid compounds, potentially derived from carotenoids, are important components of flavor and aroma in many fruits, vegetables and ornamentals. Despite their importance, little is known about the enzymes that generate these volatiles. The tomato genome contains two closely related genes potentially encoding carotenoid cleavage dioxygenases, LeCCD1A and LeCCD1B. A quantitative reverse transcriptase-polymerase chain reaction analysis revealed that one of these two genes, LeCCD1B, is highly expressed in ripening fruit (4 days post-breaker), where it constitutes 0.11% of total RNA. Unlike the related neoxanthin cleavage dioxygenases, import assays using pea chloroplasts showed that the LeCCD1 proteins are not plastid-localized. The biochemical functions of the LeCCD1 proteins were determined by bacterial expression and in vitro assays, where it was shown that they symmetrically cleave multiple carotenoid substrates at the 9,10 (9',10') positions to produce a C14 dialdehyde and two C13 cyclohexones that vary depending on the substrate. The potential roles of the LeCCD1 genes in vivo were assessed in transgenic tomato plants constitutively expressing the LeCCD1B gene in reverse orientation. This over-expression of the antisense transcript led to 87-93% reductions in mRNA levels of both LeCCD1A and LeCCD1B in the leaves and fruits of selected lines. Transgenic plants exhibited no obvious morphological alterations. High-performance liquid chromatography analysis showed no significant modification in the carotenoid content of fruit tissue. However, volatile analysis showed a > or =50% decrease in beta-ionone (a beta-carotene-derived C13 cyclohexone) and a > or =60% decrease in geranylacetone (a C13 acyclic product likely derived from a lycopene precursor) in selected lines, implicating the LeCCD1 genes in the formation of these important flavor volatiles in vivo.
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Affiliation(s)
- Andrew J Simkin
- Horticultural Sciences, Plant Molecular and Cellular Biology Program, PO Box 110690, University of Florida, Gainesville, FL 32611-0690, USA
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Simkin AJ, Underwood BA, Auldridge M, Loucas HM, Shibuya K, Schmelz E, Clark DG, Klee HJ. Circadian regulation of the PhCCD1 carotenoid cleavage dioxygenase controls emission of beta-ionone, a fragrance volatile of petunia flowers. PLANT PHYSIOLOGY 2004; 136:3504-14. [PMID: 15516502 PMCID: PMC527150 DOI: 10.1104/pp.104.049718] [Citation(s) in RCA: 185] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2004] [Revised: 08/20/2004] [Accepted: 08/20/2004] [Indexed: 05/18/2023]
Abstract
Carotenoids are thought to be the precursors of terpenoid volatile compounds that contribute to flavor and aroma. One such volatile, beta-ionone, is important to fragrance in many flowers, including petunia (Petunia hybrida). However, little is known about the factors regulating its synthesis in vivo. The petunia genome contains a gene encoding a 9,10(9',10') carotenoid cleavage dioxygenase, PhCCD1. The PhCCD1 is 94% identical to LeCCD1A, an enzyme responsible for formation of beta-ionone in tomato (Lycopersicon esculentum; Simkin AJ, Schwartz SH, Auldridge M, Taylor MG, Klee HJ [2004] Plant J [in press]). Reduction of PhCCD1 transcript levels in transgenic plants led to a 58% to 76% decrease in beta-ionone synthesis in the corollas of selected petunia lines, indicating a significant role for this enzyme in volatile synthesis. Quantitative reverse transcription-PCR analysis revealed that PhCCD1 is highly expressed in corollas and leaves, where it constitutes approximately 0.04% and 0.02% of total RNA, respectively. PhCCD1 is light-inducible and exhibits a circadian rhythm in both leaves and flowers. beta-Ionone emission by flowers occurred principally during daylight hours, paralleling PhCCD1 expression in corollas. The results indicate that PhCCD1 activity and beta-ionone emission are likely regulated at the level of transcript.
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Affiliation(s)
- Andrew J Simkin
- Horticultural Sciences, Plant Molecular and Cellular Biology Program, University of Florida, Gainesville, Florida 32611-0690, USA
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Nicolaisen M. Partial Molecular Characterization of Dahlia mosaic virus and Its Detection by PCR. PLANT DISEASE 2003; 87:945-948. [PMID: 30812800 DOI: 10.1094/pdis.2003.87.8.945] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Dahlia mosaic virus (DMV) is the causal agent of one of the most important diseases of Dahlia pinnata. The nucleotide sequence of a 1,195-bp fragment of its genome was amplified and characterized. Based on this sequence, polymerase chain reaction (PCR) assays were developed for detection of DMV. The nucleotide sequence confirmed the classification of DMV as a member of genus Caulimovirus since it was similar to a region covering partly open reading frames (ORFs) IV and V found in caulimoviruses. The two most closely related viruses on the basis of comparison of ORF V fragments were shown to be Figwort mosaic virus and Mirabilis mosaic virus with 66.6 and 68.1% identity, respectively. Two PCR assays were developed using identical primer pairs: a real-time PCR based on SYBR green chemistry and a conventional PCR. Both methods clearly discriminated DMV-infected and healthy dahlia. The real-time PCR assay detected DMV-infected material that was diluted 105-fold in healthy material.
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Affiliation(s)
- M Nicolaisen
- Department of Plant Protection, Danish Institute of Agricultural Sciences, Flakkebjerg, DK4200 Slagelse, Denmark
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Bhattacharyya S, Dey N, Maiti IB. Analysis of cis-sequence of subgenomic transcript promoter from the Figwort mosaic virus and comparison of promoter activity with the cauliflower mosaic virus promoters in monocot and dicot cells. Virus Res 2002; 90:47-62. [PMID: 12457962 DOI: 10.1016/s0166-0934(02)00146-5] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A sub-genomic transcript (Sgt) promoter was isolated from the Figwort mosaic virus (FMV) genomic clone. The FMV Sgt promoter was linked to heterologous coding sequences to form a chimeric gene construct. The 5'-3'-boundaries required for maximal activity and involvement of cis-sequences for optimal expression in plants were defined by 5'-, 3'-end deletion and internal deletion analysis of FMV Sgt promoter fragments coupled with a beta-glucuronidase reporter gene in both transient protoplast expression experiments and in transgenic plants. A 301 bp FMV Sgt promoter fragment (sequence -270 to +31 from the transcription start site; TSS) provided maximum promoter activity. The TSS of the FMV Sgt promoter was determined by primer extension analysis using total RNA from transgenic plants developed for FMV Sgt promoter: uidA fusion gene. An activator domain located upstream of the TATA box at -70 to -100 from TSS is absolutely required for promoter activity and its function is critically position-dependent with respect to TATA box. Two sequence motifs AGATTTTAAT (coordinates -100 to -91) and GTAAGCGC (coordinates -80 to -73) were found to be essential for promoter activity. The FMV Sgt promoter is less active in monocot cells; FMV Sgt promoter expression level was about 27.5-fold higher in tobacco cells compared to that in maize cells. Comparative expression analysis of FMV Sgt promoter with cauliflower mosaic virus (CaMV) 35S promoter showed that the FMV Sgt promoter is about 2-fold stronger than the CaMV 35S promoter. The FMV Sgt promoter is a constitutive promoter; expression level in seedlings was in the order: root>leaf>stem.
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Affiliation(s)
- Somnath Bhattacharyya
- Molecular Plant Virology and Plant Genetic Engineering Laboratory, Tobacco and Health Research Institute, University of Kentucky, Lexington, KY 40546-0236, USA
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Tsuge S, Okuno T, Furusawa I, Kubo Y, Horino O. Stabilization of cauliflower mosaic virus P3 tetramer by covalent linkage. Microbiol Immunol 2002; 45:365-71. [PMID: 11471824 DOI: 10.1111/j.1348-0421.2001.tb02632.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cauliflower mosaic virus (CaMV) open reading frame (ORF) III encodes a 15 kDa protein (P3) that is indispensable for viral infectivity. Although P3 has been shown to be a prerequisite for CaMV aphid transmission, its role in viral replication remains unknown. We previously showed that P3 forms a tetramer in planta and that P3 tetramer co-sediments with viral coat protein on sucrose gradient centrifugation, suggesting that a tetramer may be the functional form of P3. We presumed that disulfide bonds were involved in tetramer formation because 1) the tetramer was detected by Western blotting after electrophoresis under non-reducing conditions, and 2) the cysteine-X-cysteine motif is well conserved in CaMV P3 and P3 homologues among Caulimoviruses. Therefore we mutated either or both of the cysteine residues of CaMV P3. The mutant viruses were infectious and accumulated to a similar extent as the wild-type. An analysis of mutant proteins confirmed that the wild-type P3 molecules in the tetramer are covalently bound with one another through disulfide bonds. It was also suggested that mutant proteins are less stable than wild-type protein in planta. Furthermore, sedimentation study suggested that the disulfide bonds are involved in stable association of P3 with CaMV virions or virion-like particles, or both. The mutant viruses could be transmitted by aphids. These results suggested that the covalent bonds in P3 tetramer are dispensable for biological activity of P3 under experimental situations and may have some biological significance in natural infection in the field.
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Affiliation(s)
- S Tsuge
- Laboratory of Plant Pathology, Faculty of Agriculture, Kyoto Prefectural University, Kyoto, Japan.
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Corbin DR, Grebenok RJ, Ohnmeiss TE, Greenplate JT, Purcell JP. Expression and chloroplast targeting of cholesterol oxidase in transgenic tobacco plants. PLANT PHYSIOLOGY 2001; 126:1116-28. [PMID: 11457962 PMCID: PMC116468 DOI: 10.1104/pp.126.3.1116] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2001] [Revised: 02/28/2001] [Accepted: 04/06/2001] [Indexed: 05/23/2023]
Abstract
Cholesterol oxidase represents a novel type of insecticidal protein with potent activity against the cotton boll weevil (Anthonomus grandis grandis Boheman). We transformed tobacco (Nicotiana tabacum) plants with the cholesterol oxidase choM gene and expressed cytosolic and chloroplast-targeted versions of the ChoM protein. Transgenic leaf tissues expressing cholesterol oxidase exerted insecticidal activity against boll weevil larvae. Our results indicate that cholesterol oxidase can metabolize phytosterols in vivo when produced cytosolically or when targeted to chloroplasts. The transgenic plants exhibiting cytosolic expression accumulated low levels of saturated sterols known as stanols, and displayed severe developmental aberrations. In contrast, the transgenic plants expressing chloroplast-targeted cholesterol oxidase maintained a greater accumulation of stanols, and appeared phenotypically and developmentally normal. These results are discussed within the context of plant sterol distribution and metabolism.
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Affiliation(s)
- D R Corbin
- Monsanto Company, Plant Protection Department, 700 Chesterfield Parkway North, St. Louis, Missouri 63198, USA.
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Tieman DM, Ciardi JA, Taylor MG, Klee HJ. Members of the tomato LeEIL (EIN3-like) gene family are functionally redundant and regulate ethylene responses throughout plant development. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2001; 26:47-58. [PMID: 11359609 DOI: 10.1046/j.1365-313x.2001.01006.x] [Citation(s) in RCA: 142] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The plant hormone ethylene regulates many aspects of growth, development and responses to the environment. The Arabidopsis ETHYLENE INSENSITIVE3 (EIN3) protein is a nuclear-localized component of the ethylene signal-transduction pathway with DNA-binding activity. Loss-of-function mutations in this protein result in ethylene insensitivity in Arabidopsis. To gain a better understanding of the ethylene signal-transduction pathway in tomato, we have identified three homologs of the Arabidopsis EIN3 gene (LeEILs). Each of these genes complemented the ein3-1 mutation in transgenic Arabidopsis, indicating that all are involved in ethylene signal transduction. Transgenic tomato plants with reduced expression of a single LeEIL gene did not exhibit significant changes in ethylene response; reduced expression of multiple tomato LeEIL genes was necessary to reduce ethylene sensitivity significantly. Reduced LeEIL expression affected all ethylene responses examined, including leaf epinasty, flower abscission, flower senescence and fruit ripening. Our results indicate that the LeEILs are functionally redundant and positive regulators of multiple ethylene responses throughout plant development.
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Affiliation(s)
- D M Tieman
- PO Box 110690, Horticultural Sciences Department, University of Florida, Gainesville, FL 32611-0690, USA
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Tieman DM, Taylor MG, Ciardi JA, Klee HJ. The tomato ethylene receptors NR and LeETR4 are negative regulators of ethylene response and exhibit functional compensation within a multigene family. Proc Natl Acad Sci U S A 2000; 97:5663-8. [PMID: 10792050 PMCID: PMC25885 DOI: 10.1073/pnas.090550597] [Citation(s) in RCA: 192] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The plant hormone ethylene is involved in many developmental processes, including fruit ripening, abscission, senescence, and leaf epinasty. Tomato contains a family of ethylene receptors, designated LeETR1, LeETR2, NR, LeETR4, and LeETR5, with homology to the Arabidopsis ETR1 ethylene receptor. Transgenic plants with reduced LeETR4 gene expression display multiple symptoms of extreme ethylene sensitivity, including severe epinasty, enhanced flower senescence, and accelerated fruit ripening. Therefore, LeETR4 is a negative regulator of ethylene responses. Reduced expression of this single gene affects multiple developmental processes in tomato, whereas in Arabidopsis multiple ethylene receptors must be inactivated to increase ethylene response. Transgenic lines with reduced NR mRNA levels exhibit normal ethylene sensitivity but elevated levels of LeETR4 mRNA, indicating a functional compensation of LeETR4 for reduced NR expression. Overexpression of NR in lines with lowered LeETR4 gene expression eliminates the ethylene-sensitive phenotype, indicating that despite marked differences in structure these ethylene receptors are functionally redundant.
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Affiliation(s)
- D M Tieman
- Horticultural Sciences, University of Florida, P.O. Box 110690, Gainesville, FL 32611-0690, USA
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Ciardi JA, Tieman DM, Lund ST, Jones JB, Stall RE, Klee HJ. Response to Xanthomonas campestris pv. vesicatoria in tomato involves regulation of ethylene receptor gene expression. PLANT PHYSIOLOGY 2000; 123:81-92. [PMID: 10806227 PMCID: PMC58984 DOI: 10.1104/pp.123.1.81] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/1999] [Accepted: 01/24/2000] [Indexed: 05/18/2023]
Abstract
Although ethylene regulates a wide range of defense-related genes, its role in plant defense varies greatly among different plant-microbe interactions. We compared ethylene's role in plant response to virulent and avirulent strains of Xanthomonas campestris pv. vesicatoria in tomato (Lycopersicon esculentum Mill.). The ethylene-insensitive Never ripe (Nr) mutant displays increased tolerance to the virulent strain, while maintaining resistance to the avirulent strain. Expression of the ethylene receptor genes NR and LeETR4 was induced by infection with both virulent and avirulent strains; however, the induction of LeETR4 expression by the avirulent strain was blocked in the Nr mutant. To determine whether ethylene receptor levels affect symptom development, transgenic plants overexpressing a wild-type NR cDNA were infected with virulent X. campestris pv. vesicatoria. Like the Nr mutant, the NR overexpressors displayed greatly reduced necrosis in response to this pathogen. NR overexpression also reduced ethylene sensitivity in seedlings and mature plants, indicating that, like LeETR4, this receptor is a negative regulator of ethylene response. Therefore, pathogen-induced increases in ethylene receptors may limit the spread of necrosis by reducing ethylene sensitivity.
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Affiliation(s)
- J A Ciardi
- Horticultural Sciences Department, University of Florida, Gainesville 32611-0690, USA
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