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Iron Source and Medium pH Affect Nutrient Uptake and Pigment Content in Petunia hybrida ‘Madness Red’ Cultured In Vitro. Int J Mol Sci 2022; 23:ijms23168943. [PMID: 36012209 PMCID: PMC9409069 DOI: 10.3390/ijms23168943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 08/03/2022] [Accepted: 08/09/2022] [Indexed: 11/16/2022] Open
Abstract
Deficiency or excess of iron (Fe) and improper medium pH will inhibit the growth and development of plants, reduce the transfer and utilization of energy from the root to the leaf, and affect the utilization efficiency of inorganic nutrients. The most common symptom of Fe deficiency in plants is chlorosis of the young leaves. In this study, the effects of the iron source, in combination with the medium pH, on plant growth and development, plant pigment synthesis, and nutrient uptake in a model plant Petunia hybrida cultured in vitro were investigated. Iron sulfate (FeSO4·7H2O) or iron chelated with ethylenediaminetetraacetic acid (Fe-EDTA) were supplemented to the MNS (a multipurpose nutrient solution) medium at a concentration of 2.78 mg·L−1 Fe, and the treatment without any Fe was used as the control. The pH of the agar-solidified medium was adjusted to either 4.70, 5.70, or 6.70 before autoclaving. The experiment was carried out in an environmentally controlled culture room with a temperature of 24 °C with 100 µmol·m−2·s−1 photosynthetic photon flux density (PPFD) supplied by white light emitting diodes (LEDs) during a photoperiod of 16 h a day, 18 °C for 8 h a day in the dark, and 70% relative humidity. Regardless of the Fe source including the control, the greatest number of leaves was observed at pH 4.70. However, the greatest lengths of the leaf and root were observed in the treatment with Fe-EDTA combined with pH 5.70. The contents of the chlorophyll, carotenoid, and anthocyanin decreased with increasing medium pH, and contents of these plant pigments were positively correlated with the leaf color. The highest soluble protein content and activities of APX and CAT were observed in the Fe-EDTA under pH 5.70. However, the GPX activity was the highest in the control under pH 4.70. In addition, the highest contents of ammonium (NH4+) and nitrate (NO3−) were measured in the FeSO4-4.7 and EDTA-5.7, respectively. More than that, the treatment of Fe-EDTA combined with pH 5.70 (EDTA-5.7) enhanced nutrient absorption, as proven by the highest tissue contents of P, K, Ca, Mg, Fe, and Mn. The genes’ ferric reduction oxidase 1 and 8 (PhFRO1 and PhFRO8), iron-regulated transporter 1 (PhIRT1), nitrate transporter 2.5 (PhNRT2.5), and deoxyhypusine synthase (PhDHS) were expressed at the highest levels in this treatment as well. In the treatment of EDTA-5.7, the reduction and transport of chelated iron in P. hybrida leaves were enhanced, which also affected the transport of nitrate and catalyzed chlorophyll level in leaves. In conclusion, when the medium pH was adjusted to 5.70, supplementation of chelated Fe-EDTA was more conducive to promoting the growth and development of, and absorption of mineral nutrients by, the plant and the expression of related genes in the leaves.
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Massa S, Pagliarello R, Cemmi A, Di Sarcina I, Bombarely A, Demurtas OC, Diretto G, Paolini F, Petzold HE, Bliek M, Bennici E, Del Fiore A, De Rossi P, Spelt C, Koes R, Quattrocchio F, Benvenuto E. Modifying Anthocyanins Biosynthesis in Tomato Hairy Roots: A Test Bed for Plant Resistance to Ionizing Radiation and Antioxidant Properties in Space. FRONTIERS IN PLANT SCIENCE 2022; 13:830931. [PMID: 35283922 PMCID: PMC8909381 DOI: 10.3389/fpls.2022.830931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 01/07/2022] [Indexed: 06/14/2023]
Abstract
Gene expression manipulation of specific metabolic pathways can be used to obtain bioaccumulation of valuable molecules and desired quality traits in plants. A single-gene approach to impact different traits would be greatly desirable in agrospace applications, where several aspects of plant physiology can be affected, influencing growth. In this work, MicroTom hairy root cultures expressing a MYB-like transcription factor that regulates the biosynthesis of anthocyanins in Petunia hybrida (PhAN4), were considered as a testbed for bio-fortified tomato whole plants aimed at agrospace applications. Ectopic expression of PhAN4 promoted biosynthesis of anthocyanins, allowing to profile 5 major derivatives of delphinidin and petunidin together with pelargonidin and malvidin-based anthocyanins, unusual in tomato. Consistent with PhAN4 features, transcriptomic profiling indicated upregulation of genes correlated to anthocyanin biosynthesis. Interestingly, a transcriptome reprogramming oriented to positive regulation of cell response to biotic, abiotic, and redox stimuli was evidenced. PhAN4 hairy root cultures showed the significant capability to counteract reactive oxygen species (ROS) accumulation and protein misfolding upon high-dose gamma irradiation, which is among the most potent pro-oxidant stress that can be encountered in space. These results may have significance in the engineering of whole tomato plants that can benefit space agriculture.
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Affiliation(s)
- Silvia Massa
- Department for Sustainability, Biotechnology and Agro-Industry Division - Biotec Laboratory, Italian National Agency for New Technologies, Energy and Sustainable Economic Development, Rome, Italy
| | - Riccardo Pagliarello
- Department for Sustainability, Biotechnology and Agro-Industry Division - Biotec Laboratory, Italian National Agency for New Technologies, Energy and Sustainable Economic Development, Rome, Italy
- Department of Agriculture and Forest Sciences, University of Tuscia, Viterbo, Italy
| | - Alessia Cemmi
- Fusion and Nuclear Safety Technologies Department, Italian National Agency for New Technologies, Energy and Sustainable Economic Development, Rome, Italy
| | - Ilaria Di Sarcina
- Fusion and Nuclear Safety Technologies Department, Italian National Agency for New Technologies, Energy and Sustainable Economic Development, Rome, Italy
| | | | - Olivia Costantina Demurtas
- Department for Sustainability, Biotechnology and Agro-Industry Division - Biotec Laboratory, Italian National Agency for New Technologies, Energy and Sustainable Economic Development, Rome, Italy
| | - Gianfranco Diretto
- Department for Sustainability, Biotechnology and Agro-Industry Division - Biotec Laboratory, Italian National Agency for New Technologies, Energy and Sustainable Economic Development, Rome, Italy
| | - Francesca Paolini
- 'Regina Elena' National Cancer Institute, HPV-UNIT, Department of Research, Advanced Diagnostic and Technological Innovation, Translational Research Functional Departmental Area, Rome, Italy
| | - H Earl Petzold
- School of Plants and Environmental Sciences, Virginia Tech, Blacksburg, VA, United States
| | - Mattijs Bliek
- Department of Plant Development and (Epi)Genetics, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, Netherlands
| | - Elisabetta Bennici
- Department for Sustainability, Biotechnology and Agro-Industry Division - Biotec Laboratory, Italian National Agency for New Technologies, Energy and Sustainable Economic Development, Rome, Italy
| | - Antonella Del Fiore
- Department for Sustainability, Biotechnology and Agro-Industry Division - Agrifood Sustainability, Quality, and Safety Laboratory, Italian National Agency for New Technologies, Energy and Sustainable Economic Development, Rome, Italy
| | - Patrizia De Rossi
- Energy Efficiency Unit Department - Northern Area Regions Laboratory, Casaccia Research Center, Italian National Agency for New Technologies, Energy and Sustainable Economic Development, Rome, Italy
| | - Cornelis Spelt
- Department of Plant Development and (Epi)Genetics, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, Netherlands
| | - Ronald Koes
- Department of Plant Development and (Epi)Genetics, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, Netherlands
| | - Francesca Quattrocchio
- Department of Plant Development and (Epi)Genetics, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, Netherlands
| | - Eugenio Benvenuto
- Department for Sustainability, Biotechnology and Agro-Industry Division - Biotec Laboratory, Italian National Agency for New Technologies, Energy and Sustainable Economic Development, Rome, Italy
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Pálfi P, Bakacsy L, Kovács H, Szepesi Á. Hypusination, a Metabolic Posttranslational Modification of eIF5A in Plants during Development and Environmental Stress Responses. PLANTS 2021; 10:plants10071261. [PMID: 34206171 PMCID: PMC8309165 DOI: 10.3390/plants10071261] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 06/15/2021] [Accepted: 06/21/2021] [Indexed: 12/25/2022]
Abstract
Hypusination is a unique posttranslational modification of eIF5A, a eukaryotic translation factor. Hypusine is a rare amino acid synthesized in this process and is mediated by two enzymes, deoxyhypusine synthase (DHS) and deoxyhypusine hydroxylase (DOHH). Despite the essential participation of this conserved eIF5A protein in plant development and stress responses, our knowledge of its proper function is limited. In this review, we demonstrate the main findings regarding how eIF5A and hypusination could contribute to plant-specific responses in growth and stress-related processes. Our aim is to briefly discuss the plant-specific details of hypusination and decipher those signal pathways which can be effectively modified by this process. The diverse functions of eIF5A isoforms are also discussed in this review.
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Zhang YM, Guo P, Xia X, Guo H, Li Z. Multiple Layers of Regulation on Leaf Senescence: New Advances and Perspectives. FRONTIERS IN PLANT SCIENCE 2021; 12:788996. [PMID: 34938309 PMCID: PMC8685244 DOI: 10.3389/fpls.2021.788996] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 11/03/2021] [Indexed: 05/22/2023]
Abstract
Leaf senescence is the last stage of leaf development and is an orderly biological process accompanied by degradation of macromolecules and nutrient recycling, which contributes to plant fitness. Forward genetic mutant screening and reverse genetic studies of senescence-associated genes (SAGs) have revealed that leaf senescence is a genetically regulated process, and the initiation and progression of leaf senescence are influenced by an array of internal and external factors. Recently, multi-omics techniques have revealed that leaf senescence is subjected to multiple layers of regulation, including chromatin, transcriptional and post-transcriptional, as well as translational and post-translational levels. Although impressive progress has been made in plant senescence research, especially the identification and functional analysis of a large number of SAGs in crop plants, we still have not unraveled the mystery of plant senescence, and there are some urgent scientific questions in this field, such as when plant senescence is initiated and how senescence signals are transmitted. This paper reviews recent advances in the multiple layers of regulation on leaf senescence, especially in post-transcriptional regulation such as alternative splicing.
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Affiliation(s)
- Yue-Mei Zhang
- National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, China
| | - Pengru Guo
- National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, China
| | - Xinli Xia
- National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, China
| | - Hongwei Guo
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - Zhonghai Li
- National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, China
- *Correspondence: Zhonghai Li,
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Engineered Ripening-Specific Accumulation of Polyamines Spermidine and Spermine in Tomato Fruit Upregulates Clustered C/D Box snoRNA Gene Transcripts in Concert with Ribosomal RNA Biogenesis in the Red Ripe Fruit. PLANTS 2020; 9:plants9121710. [PMID: 33291784 PMCID: PMC7762058 DOI: 10.3390/plants9121710] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 11/29/2020] [Accepted: 12/02/2020] [Indexed: 02/07/2023]
Abstract
Ripening of tomato fruit leads, in general, to a sequential decrease in the endogenous levels of polyamines spermidine (SPD) and spermine (SPM), while the trend for the diamine putrescine (PUT) levels is generally an initial decrease, followed by a substantial increase, and thereafter reaching high levels at the red ripe fruit stage. However, genetic engineering fruit-specific expression of heterologous yeast S-adenosylmethionine (SAM) decarboxylase in tomato has been found to result in a high accumulation of SPD and SPM at the cost of PUT. This system enabled a genetic approach to determine the impact of increased endogenous levels of biogenic amines SPD and SPM in tomato (579HO transgenic line) and on the biogenesis, transcription, processing, and stability of ribosomal RNA (rRNA) genes in tomato fruit as compared with the non-transgenic 556AZ line. One major biogenetic process regulating transcription and processing of pre-mRNA complexes in the nucleus involves small nucleolar RNAs (snoRNAs). To determine the effect of high levels of SPD and SPM on these latter processes, we cloned, sequenced, and identified a box C/D snoRNA cluster in tomato, namely, SlSnoR12, SlU24a, Slz44a, and Slz132b. Similar to this snoRNA cluster housed on chromosome (Chr.) 6, two other noncoding C/D box genes, SlsnoR12.2 and SlU24b, with a 94% identity to those on Chr. 6 were found located on Chr. 3. We also found that other snoRNAs divisible into snoRNA subclusters A and B, separated by a uridine rich spacer, were decorated with other C/D box snoRNAs, namely, J10.3, Z131a/b, J10.1, and Z44a, followed by z132a, J11.3, z132b, U24, Z20, U24a, and J11. Several of these, for example, SlZ44a, Slz132b, and SlU24a share conserved sequences similar to those in Arabidopsis and rice. RNAseq analysis of high SPD/SPM transgenic tomatoes (579HO line) showed significant enrichment of RNA polymerases, ribosomal, and translational protein genes at the breaker+8 ripening stage as compared with the 556AZ control. Thus, these results indicate that SPD/SPM regulates snoRNA and rRNA expression directly or indirectly, in turn, affecting protein synthesis, metabolism, and other cellular activities in a positive manner.
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Kok SY, Namasivayam P, Ee GCL, Ong-Abdullah M. Comparative proteomic analysis of oil palm (Elaeis guineensis Jacq.) during early fruit development. J Proteomics 2020; 232:104052. [PMID: 33262095 DOI: 10.1016/j.jprot.2020.104052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 11/11/2020] [Accepted: 11/15/2020] [Indexed: 01/04/2023]
Abstract
To gain insights on protein changes in fruit setting and growth in oil palm, a comparative proteomic approach was undertaken to study proteome changes during its early development. The variations in the proteome at five early developmental stages were investigated via a gel-based proteomic technique. A total of 129 variant proteins were determined using mass spectrometric analysis, resulting in 80 identifications. The majority of the identified protein species were classified as energy and metabolism, stress response/defence and cell structure during early oil palm development representing potential candidates for the control of final fruit size and composition. Seven prominent protein species were then characterised using real-time polymerase chain reaction to validate the mRNA expression against the protein abundant profiles. Transcript and protein profiles were parallel across the developmental stages, but divergent expression was observed in one protein spot, indicative of possible post-transcriptional events. Our results revealed protein changes in early oil palm fruit development provide valuable information in the understanding of fruit growth and metabolism during early stages that may contribute towards improving agronomic traits. BIOLOGICAL SIGNIFICANCE: Two-dimensional gel electrophoresis coupled with mass spectrometry approach was used in this study to identify differentially expressed proteins during early oil palm fruit development. A total of 80 protein spots with significant change in abundance were successfully identified and selected genes were analysed using real time PCR to validate their expression. The dynamic changes in oil palm fruit proteome during early development were mostly active in primary and energy metabolism, stress responses, cell structure and protein metabolism. This study reveals the physiological processes during early oil palm fruit development and provides a reference proteome for further improvements in fruit quality traits.
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Affiliation(s)
- Sau-Yee Kok
- Advanced Biotechnology and Breeding Centre, Malaysian Palm Oil Board (MPOB), No. 6 Persiaran Institusi, Bandar Baru Bangi, Kajang, Selangor, Malaysia; Division of Genetics, Cancer Research Institute, Kanazawa University, Kanazawa, Japan
| | - Parameswari Namasivayam
- Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia; Institute of Tropical Agriculture, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - Gwendoline Cheng-Lian Ee
- Department of Chemistry, Faculty of Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - Meilina Ong-Abdullah
- Advanced Biotechnology and Breeding Centre, Malaysian Palm Oil Board (MPOB), No. 6 Persiaran Institusi, Bandar Baru Bangi, Kajang, Selangor, Malaysia.
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Liu J, Chang X, Ding B, Zhong S, Peng L, Wei Q, Meng J, Yu Y. PhDHS Is Involved in Chloroplast Development in Petunia. FRONTIERS IN PLANT SCIENCE 2019; 10:284. [PMID: 30930919 PMCID: PMC6424912 DOI: 10.3389/fpls.2019.00284] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 02/20/2019] [Indexed: 05/06/2023]
Abstract
Deoxyhypusine synthase (DHS) is encoded by a nuclear gene and is the key enzyme involved in the post-translational activation of the eukaryotic translation initiation factor eIF5A. DHS plays important roles in plant growth and development. To gain a better understanding of DHS, the petunia (Petunia hybrida) PhDHS gene was isolated, and the role of PhDHS in plant growth was analyzed. PhDHS protein was localized to the nucleus and cytoplasm. Virus-mediated PhDHS silencing caused a sectored chlorotic leaf phenotype. Chlorophyll levels and photosystem II activity were reduced, and chloroplast development was abnormal in PhDHS-silenced leaves. In addition, PhDHS silencing resulted in extended leaf longevity and thick leaves. A proteome assay revealed that 308 proteins are upregulated and 266 proteins are downregulated in PhDHS-silenced plants compared with control, among the latter, 21 proteins of photosystem I and photosystem II and 12 thylakoid (thylakoid lumen and thylakoid membrane) proteins. In addition, the mRNA level of PheIF5A-1 significantly decreased in PhDHS-silenced plants, while that of another three PheIF5As were not significantly affected in PhDHS-silenced plants. Thus, silencing of PhDHS affects photosynthesis presumably as an indirect effect due to reduced expression of PheIF5A-1 in petunia. Significance: PhDHS-silenced plants develop yellow leaves and exhibit a reduced level of photosynthetic pigment in mesophyll cells. In addition, arrested development of chloroplasts is observed in the yellow leaves.
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Li LJ, Lu XC, Ma HY, Lyu DG. Comparative proteomic analysis reveals the roots response to low root-zone temperature in Malus baccata. JOURNAL OF PLANT RESEARCH 2018; 131:865-878. [PMID: 29855747 DOI: 10.1007/s10265-018-1045-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2018] [Accepted: 05/10/2018] [Indexed: 05/16/2023]
Abstract
Soil temperature is known to affect plant growth and productivity. In this study we found that low root-zone temperature (LRT) inhibited the growth of apple (Malus baccata Borkh.) seedlings. To elucidate the molecular mechanism of LRT response, we performed comparative proteome analysis of the apple roots under LRT for 6 days. Total proteins of roots were extracted and separated by two-dimensional gel electrophoresis (2-DE) and 29 differentially accumulated proteins were successfully identified by MALDI-TOF/TOF mass spectrometry. They were involved in protein transport/processing/degradation (21%), glycometabolism (20%), response to stress (14%), oxidoreductase activity (14%), protein binding (7%), RNA metabolism (7%), amino acid biosynthesis (3%) and others (14%). The results revealed that LRT inhibited glycometabolism and RNA metabolism. The up-regulated proteins which were associated with oxidoreductase activity, protein metabolism and defense response, might be involved in protection mechanisms against LRT stress in the apple seedlings. Subsequently, 8 proteins were selected for the mRNA quantification analysis, and we found 6 of them were consistently regulated between protein and mRNA levels. In addition, the enzyme activities in ascorbate-glutathione (AsA-GSH) cycle were determined, and APX activity was increased and GR activity was decreased under LRT, in consistent with the protein levels. This study provides new insights into the molecular mechanisms of M. baccata in responding to LRT.
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Affiliation(s)
- Li-Jie Li
- College of Horticulture, Shenyang Agricultural University, Shenyang, 110866, China
| | - Xiao-Chen Lu
- College of Horticulture, Shenyang Agricultural University, Shenyang, 110866, China
| | - Huai-Yu Ma
- College of Horticulture, Shenyang Agricultural University, Shenyang, 110866, China.
- Key Lab of Fruit Quality Development and Regulation of Liaoning Province, Shenyang, 110866, China.
| | - De-Guo Lyu
- College of Horticulture, Shenyang Agricultural University, Shenyang, 110866, China.
- Key Lab of Fruit Quality Development and Regulation of Liaoning Province, Shenyang, 110866, China.
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Tian MQ, Jiang K, Takahashi I, Li GD. Strigolactone-induced senescence of a bamboo leaf in the dark is alleviated by exogenous sugar. JOURNAL OF PESTICIDE SCIENCE 2018; 43:173-179. [PMID: 30363134 PMCID: PMC6140682 DOI: 10.1584/jpestics.d18-003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Strigolactones (SLs) are a series of sesquiterpene lactones that serve as plant hormones to regulate plant growth and development, such as shoot branching, lateral root formation, and root hair elongation. Recently, SLs have been reported to accelerate the leaf senescence, which is also regulated by sugar signals. In this study, we utilized segments of a bamboo leaf to observe leaf senescence and confirmed that SL accelerates leaf senescence and triggers cell death under a dark condition rather than under a light condition. Further studies showed that the co-treatment of sugars suppressed SL-induced leaf senescence and cell death under dark conditions, suggesting a crosstalk between SL and the sugar signal in regulating leaf senescence.
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Affiliation(s)
- Man-qing Tian
- The Nurturing Station for the State Key Laboratory of Subtropical Silviculture, Zhejiang Agriculture and Forestry University, 666, Wusu Rd, Lin’an, China
| | - Kai Jiang
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113–8657, Japan
| | - Ikuo Takahashi
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113–8657, Japan
| | - Guo-dong Li
- The Nurturing Station for the State Key Laboratory of Subtropical Silviculture, Zhejiang Agriculture and Forestry University, 666, Wusu Rd, Lin’an, China
- To whom correspondence should be addressed. E-mail:
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Chen H, Adam Arsovski A, Yu K, Wang A. Deep sequencing leads to the identification of eukaryotic translation initiation factor 5A as a key element in Rsv1-mediated lethal systemic hypersensitive response to Soybean mosaic virus infection in soybean. MOLECULAR PLANT PATHOLOGY 2017; 18:391-404. [PMID: 27019403 PMCID: PMC6638201 DOI: 10.1111/mpp.12407] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 03/23/2016] [Accepted: 03/25/2016] [Indexed: 05/23/2023]
Abstract
Rsv1, a single dominant resistance locus in soybean, confers extreme resistance to the majority of Soybean mosaic virus (SMV) strains, but is susceptible to the G7 strain. In Rsv1-genotype soybean, G7 infection provokes a lethal systemic hypersensitive response (LSHR), a delayed host defence response. The Rsv1-mediated LSHR signalling pathway remains largely unknown. In this study, we employed a genome-wide investigation to gain an insight into the molecular interplay between SMV G7 and Rsv1-genotype soybean. Small RNA (sRNA), degradome and transcriptome sequencing analyses were used to identify differentially expressed genes (DEGs) and microRNAs (DEMs) in response to G7 infection. A number of DEGs, DEMs and microRNA targets, and the interaction network of DEMs and their target mRNAs responsive to G7 infection, were identified. Knock-down of one of the identified DEGs, the eukaryotic translation initiation factor 5A (eIF5A), diminished the LSHR and enhanced viral accumulation, suggesting the essential role of eIF5A in the G7-induced, Rsv1-mediated LSHR signalling pathway. This work provides an in-depth genome-wide analysis of high-throughput sequencing data, and identifies multiple genes and microRNA signatures that are associated with the Rsv1-mediated LSHR.
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Affiliation(s)
- Hui Chen
- London Research and Development Centre, Agriculture and Agri‐Food CanadaOttawaONCanadaN5T 4T3
- Department of BiologyUniversity of Western OntarioLondonONCanadaN6A 5B7
| | - Andrej Adam Arsovski
- London Research and Development Centre, Agriculture and Agri‐Food CanadaOttawaONCanadaN5T 4T3
| | - Kangfu Yu
- Greenhouse and Processing Crops Research Centre, Agriculture and Agri‐Food CanadaHarrowONCanadaN0R 1G0
| | - Aiming Wang
- London Research and Development Centre, Agriculture and Agri‐Food CanadaOttawaONCanadaN5T 4T3
- Department of BiologyUniversity of Western OntarioLondonONCanadaN6A 5B7
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Ermert AL, Mailliet K, Hughes J. Holophytochrome-Interacting Proteins in Physcomitrella: Putative Actors in Phytochrome Cytoplasmic Signaling. FRONTIERS IN PLANT SCIENCE 2016; 7:613. [PMID: 27242820 PMCID: PMC4867686 DOI: 10.3389/fpls.2016.00613] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2016] [Accepted: 04/21/2016] [Indexed: 05/26/2023]
Abstract
Phytochromes are the principle photoreceptors in light-regulated plant development, primarily acting via translocation of the light-activated photoreceptor into the nucleus and subsequent gene regulation. However, several independent lines of evidence indicate unambiguously that an additional cytoplasmic signaling mechanism must exist. Directional responses in filament tip cells of the moss Physcomitrella patens are steered by phy4 which has been shown to interact physically with the blue light receptor phototropin at the plasma membrane. This complex might perceive and transduce vectorial information leading to cytoskeleton reorganization and finally a directional growth response. We developed yeast two-hybrid procedures using photochemically functional, full-length phy4 as bait in Physcomitrella cDNA library screens and growth assays under different light conditions, revealing Pfr-dependent interactions possibly associated with phytochrome cytoplasmic signaling. Candidate proteins were then expressed in planta with fluorescent protein tags to determine their intracellular localization in darkness and red light. Of 14 candidates, 12 were confirmed to interact with phy4 in planta using bimolecular fluorescence complementation. We also used database information to study their expression patterns relative to those of phy4. We discuss the likely functional characteristics of these holophytochrome-interacting proteins (HIP's) and their possible roles in signaling.
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Wang L, Huang GQ, Sun Y, Li Y, Yao WJ, Jiang TB. Cloning and expression analysis of eIF-5A gene in Apocynum venetum. BIOTECHNOL BIOTEC EQ 2016. [DOI: 10.1080/13102818.2016.1172944] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Affiliation(s)
- Lei Wang
- Department of Biotechnology, Institute of Advanced Technology, Heilongjiang Academy of Sciences, Harbin, PR China
- Department of Plant Science, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, PR China
| | - Guo-Qing Huang
- Department of Biotechnology, Institute of Advanced Technology, Heilongjiang Academy of Sciences, Harbin, PR China
| | - Yao Sun
- Department of Biotechnology, Institute of Advanced Technology, Heilongjiang Academy of Sciences, Harbin, PR China
| | - Yao Li
- Department of Biotechnology, Institute of Advanced Technology, Heilongjiang Academy of Sciences, Harbin, PR China
| | - Wen-Jing Yao
- State Key Laboratory of Tree Genetics and Breeding, College of Forestry, Northeast Forestry University, Harbin, PR China
| | - Ting-Bo Jiang
- State Key Laboratory of Tree Genetics and Breeding, College of Forestry, Northeast Forestry University, Harbin, PR China
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Liu X, Zhai R, Feng W, Zhang S, Wang Z, Qiu Z, Zhang J, Ma F, Xu L. Proteomic analysis of 'Zaosu' pear (Pyrus bretschneideri Rehd.) and its early-maturing bud sport. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2014; 224:120-35. [PMID: 24908513 DOI: 10.1016/j.plantsci.2014.04.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 04/13/2014] [Accepted: 04/16/2014] [Indexed: 05/09/2023]
Abstract
Maturation of fruits involves a series of physiological, biochemical, and organoleptic changes that eventually make fleshy fruits attractive, palatable, and nutritional. In order to understand the mature mechanism of the early-maturing bud sport of 'Zaosu' pear, we analyzed the differences of proteome expression between the both pears in different mature stages by the methods of a combination of two-dimensional electrophoresis (2-DE) and matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) analysis. Seventy-five differential expressed protein spots (p<0.05) were obtained between 'Zaosu' pear and its early-maturing bud sport, but only sixty-eight were demonstratively identified in the database of NCBI and uniprot. The majority of proteins were linked to metabolism, energy, stress response/defense and cell structure. Additionally, our data confirmed an increase of proteins related to cell-wall modification, oxidative stress and pentose phosphate metabolism and a decrease of proteins related to photosynthesis and glycolysis during the development process of both pears, but all these proteins increased or decreased faster in the early-maturing bud sport. This comparative analysis between both pears showed that these proteins were closely associated with maturation and could provide more detailed characteristics of the maturation process of both pears.
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Affiliation(s)
- Xueting Liu
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China; Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Yangling, Shaanxi 712100, China
| | - Rui Zhai
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China; Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Yangling, Shaanxi 712100, China
| | - Wenting Feng
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China; Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Yangling, Shaanxi 712100, China
| | - Shiwei Zhang
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China; Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Yangling, Shaanxi 712100, China
| | - Zhigang Wang
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China; Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Yangling, Shaanxi 712100, China
| | - Zonghao Qiu
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China; Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Yangling, Shaanxi 712100, China
| | - Junke Zhang
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China; Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Yangling, Shaanxi 712100, China
| | - Fengwang Ma
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China; Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Yangling, Shaanxi 712100, China
| | - Lingfei Xu
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China; Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Yangling, Shaanxi 712100, China.
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14
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Parkash J, Vaidya T, Kirti S, Dutt S. Translation initiation factor 5A in Picrorhiza is up-regulated during leaf senescence and in response to abscisic acid. Gene 2014; 542:1-7. [PMID: 24656625 DOI: 10.1016/j.gene.2014.03.032] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 03/17/2014] [Indexed: 11/25/2022]
Abstract
Translation initiation, the first step of protein synthesis process is the principal regulatory step controlling translation and involves a pool of translation initiation factors. In plants, from recent studies it is becoming evident that these translation initiation factors impact various aspects of plant growth and development in addition to their role in protein synthesis. Eukaryotic translation initiation factor eIF5A is one such factor which functions in start site selection for the eIF2-GTP-tRNAi ternary complex within the ribosomal-bound preinitiation complex and also stabilizes the binding of GDP to eIF2. In the present study we have cloned and analysed a gene (eIF5a) encoding eIF5A from Picrorhiza (Picrorhiza kurrooa Royle ex Benth.) a medicinal plant of the western Himalayan region. The full length eIF5a cDNA consisted of 838 bp with an open reading frame of 480 bp, 88 bp 5' untranslated region and 270 bp 3' untranslated region. The deduced eIF5A protein contained 159 amino acids with a molecular weight of 17.359 kDa and an isoelectric point of 5.59. Secondary structure analysis revealed eIF5A having 24.53% α-helices, 8.81% β-turns, 23.27% extended strands and 43.40% random coils. pk-eIF5a transcript was found to be expressing during the active growth phase as well as during leaf senescence stage, however, highest expression was observed during leaf senescence stage. Further, its expression was up-regulated in response to exogenous application of abscisic acid. Both high intensity as well as low intensity light decreased the expression of pk-eIF5a. The findings suggest eIF5a to be an important candidate to develop genetic engineering based strategies for delaying leaf senescence.
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Affiliation(s)
- Jai Parkash
- Academy of Scientific and Innovative Research-IHBT (AcSIR-IHBT), India; Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology (CSIR-IHBT), Palampur, Himachal Pradesh 176061, India
| | - Tanmay Vaidya
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology (CSIR-IHBT), Palampur, Himachal Pradesh 176061, India
| | - Shruti Kirti
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology (CSIR-IHBT), Palampur, Himachal Pradesh 176061, India
| | - Som Dutt
- Academy of Scientific and Innovative Research-IHBT (AcSIR-IHBT), India; Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology (CSIR-IHBT), Palampur, Himachal Pradesh 176061, India.
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15
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Rossi D, Kuroshu R, Zanelli CF, Valentini SR. eIF5A and EF-P: two unique translation factors are now traveling the same road. WILEY INTERDISCIPLINARY REVIEWS. RNA 2014; 5:209-22. [PMID: 24402910 DOI: 10.1002/wrna.1211] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 11/01/2013] [Accepted: 11/06/2013] [Indexed: 11/09/2022]
Abstract
Translational control is extremely important in all organisms, and some of its aspects are highly conserved among all primary kingdoms, such as those related to the translation elongation step. The previously classified translation initiation factor 5A (eIF5A) and its bacterial homologue elongation factor P (EF-P) were discovered in the late 70's and have recently been the object of many studies. eIF5A and EF-P are the only cellular proteins that undergo hypusination and lysinylation, respectively, both of which are unique posttranslational modifications. Herein, we review all the important discoveries related to the biochemical and functional characterization of these factors, highlighting the implication of eIF5A in translation elongation instead of initiation. The findings that eIF5A and EF-P are important for specific cellular processes and play a role in the relief of ribosome stalling caused by specific amino acid sequences, such as those containing prolines reinforce the hypothesis that these factors are involved in specialized translation. Although there are some divergences between these unique factors, recent studies have clarified that they act similarly during protein synthesis. Further studies may reveal their precise mechanism of ribosome activity modulation as well as the mRNA targets that require eIF5A and EF-P for their proper translation.
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Affiliation(s)
- Danuza Rossi
- Department of Biological Sciences, School of Pharmaceutical Sciences, Univ Estadual Paulista (UNESP), Araraquara, SP, Brazil
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16
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Ren B, Chen Q, Hong S, Zhao W, Feng J, Feng H, Zuo J. The Arabidopsis eukaryotic translation initiation factor eIF5A-2 regulates root protoxylem development by modulating cytokinin signaling. THE PLANT CELL 2013; 25:3841-57. [PMID: 24163315 PMCID: PMC3877783 DOI: 10.1105/tpc.113.116236] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 09/04/2013] [Accepted: 10/06/2013] [Indexed: 05/07/2023]
Abstract
The phytohormone cytokinin regulates various aspects of plant growth and development, including root vascular development. In Arabidopsis thaliana, mutations in the cytokinin signaling components cause misspecification of protoxylem cell files. Auxin antagonizes cytokinin-regulated root protoxylem differentiation by inducing expression of Arabidopsis phosphotransfer protein6 (AHP6), a negative regulator of cytokinin signaling. However, the molecular mechanism of cytokinin-regulated protoxylem differentiation is not fully understood. Here, we show that a mutation in Arabidopsis fumonisin B1-resistant12 (FBR12), which encodes a eukaryotic translation initiation factor 5A, causes defective protoxylem development and reduced sensitivity to cytokinin. FBR12 genetically interacts with the cytokinin receptor cytokinin response1 (CRE1) and downstream AHP genes, as double mutants show enhanced phenotypes. FBR12 forms a protein complex with CRE1 and AHP1, and cytokinin regulates formation of this protein complex. Intriguingly, ahp6 partially suppresses the fbr12 mutant phenotype, and the fbr12 mutation causes increased expression of AHP6, indicating that FBR12 negatively regulates AHP6. Consistent with this, ectopic expression of FBR12 in the CRE1-expressing domain partially rescues defective protoxylem development in fbr12, and overexpression of AHP6 causes an fbr12-like phenotype. These results define a regulatory role of the highly conserved FBR12 in cytokinin-mediated root protoxylem specification.
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Affiliation(s)
- Bo Ren
- State Key Laboratory of Plant Genomics and National Plant Gene Research Center, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Qingguo Chen
- State Key Laboratory of Plant Genomics and National Plant Gene Research Center, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Sulei Hong
- State Key Laboratory of Plant Genomics and National Plant Gene Research Center, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenming Zhao
- State Key Laboratory of Plant Genomics and National Plant Gene Research Center, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jian Feng
- State Key Laboratory of Plant Genomics and National Plant Gene Research Center, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Haizhong Feng
- State Key Laboratory of Plant Genomics and National Plant Gene Research Center, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Jianru Zuo
- State Key Laboratory of Plant Genomics and National Plant Gene Research Center, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
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17
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Gupta S, Shi X, Lindquist IE, Devitt N, Mudge J, Rashotte AM. Transcriptome profiling of cytokinin and auxin regulation in tomato root. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:695-704. [PMID: 23307920 PMCID: PMC3542057 DOI: 10.1093/jxb/ers365] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Tomato is a model and economically important crop plant with little information available about gene expression in roots. Currently, there have only been a few studies that examine hormonal responses in tomato roots and none at a genome-wide level. This study examined the transcriptome atlas of tomato root regions (root tip, lateral roots, and whole roots) and the transcriptional regulation of each root region in response to the plant hormones cytokinin and auxin using Illumina RNA sequencing. More than 165 million 1×54 base pair reads were mapped onto the Solanum lycopersicum reference genome and differential expression patterns in each root region in response to each hormone were assessed. Many novel cytokinin- and auxin-induced and -repressed genes were identified as significantly differentially expressed and the expression levels of several were confirmed by qPCR. A number of these regulated genes represent tomato orthologues of cytokinin- or auxin-regulated genes identified in other species, including CKXs, type-A RRs, Aux/IAAs, and ARFs. Additionally, the data confirm some of the hormone regulation studies for recently examined genes in tomato such as SlIAAs and SlGH3s. Moreover, genes expressed abundantly in each root region were identified which provide a spatial distribution of many classes of genes, including plant defence, secondary metabolite production, and general metabolism across the root. Overall this study presents the first global expression patterns of hormone-regulated transcripts in tomato roots, which will be functionally relevant for future studies directed towards tomato root growth and development.
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Affiliation(s)
- Sarika Gupta
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Xiuling Shi
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Ingrid E. Lindquist
- National Center for Genome Resources, 2935 Rodeo Park Drive East, Santa Fe, NM 87505, USA
| | - Nicholas Devitt
- National Center for Genome Resources, 2935 Rodeo Park Drive East, Santa Fe, NM 87505, USA
| | - Joann Mudge
- National Center for Genome Resources, 2935 Rodeo Park Drive East, Santa Fe, NM 87505, USA
| | - Aaron M. Rashotte
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
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18
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Identification of differentially expressed proteins involved in the early larval development of the Pacific oyster Crassostrea gigas. J Proteomics 2012; 75:3855-65. [DOI: 10.1016/j.jprot.2012.04.051] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Revised: 03/12/2012] [Accepted: 04/01/2012] [Indexed: 11/17/2022]
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19
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Lewandowska-Gnatowska E, Szymona L, Łebska M, Szczegielniak J, Muszyńska G. Phosphorylation of maize eukaryotic translation initiation factor on Ser2 by catalytic subunit CK2. Mol Cell Biochem 2011; 356:241-4. [PMID: 21750984 DOI: 10.1007/s11010-011-0952-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Accepted: 06/24/2011] [Indexed: 10/18/2022]
Abstract
Alignment of eukaryotic translation initiation factor 5A (eIF5A) sequences has shown, for plants, in contrast to most other eukaryotes, the presence of N-terminal serine residue (Ser2) which could be phosphorylated by CK2. Using point directed mutagenesis, we demonstrate here that in recombinant maize ZmeIF5Awt Ser2 is exclusively phosphorylated by catalytic subunit of CK2 (CK2α), whereas its mutated variant Ser2Ala is not phosphorylated. To shed light on the physiological significance of this Ser2 phosphorylation, transient expression of fluorescence-labeled proteins was performed in maize protoplast. Wild-type ZmeIF5A was distributed evenly between nucleus and cytoplasm, but the replacement of Ser2 by aspartic acid, which mimics the phosphorylated serine, influences its intracellular localization. We postulate that phosphorylation of Ser2 in maize eIF5A, and most probably in other plant cells, plays a role in specific regulation of nuclear export of eIF5A-bound mRNAs.
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20
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Woriedh M, Hauber I, Martinez-Rocha AL, Voigt C, Maier FJ, Schröder M, Meier C, Hauber J, Schäfer W. Preventing Fusarium head blight of wheat and cob rot of maize by inhibition of fungal deoxyhypusine synthase. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2011; 24:619-27. [PMID: 21463208 DOI: 10.1094/mpmi-03-10-0068] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Upon posttranslational activation, the eukaryotic initiation factor-5A (eIF-5A) transports a subset of mRNAs out of the nucleus to the ribosomes for translation. Activation of the protein is an evolutionary highly conserved process that is unique to eIF-5A, the conversion of a lysine to a hypusine. Instrumental for the synthesis of hypusine is the first of two enzymatic reactions mediated by deoxyhypusine synthase (DHS). We show that DHS of wheat and the pathogenic fungus Fusarium graminearum, which causes one of the most destructive crop diseases worldwide, are transcriptionally upregulated during their pathogenic interaction. Although DHS of wheat, fungus, and human can be equally inhibited by the inhibitor CNI-1493 in vitro, application during infection of wheat and maize flowers results in strong inhibition of the pathogen without interference with kernel development. Our studies provide a novel strategy to selectively inhibit fungal growth without affecting plant growth. We identified fungal DHS as a target for the development of new inhibitors, for which CNI-1493 may serve as a lead substance.
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Affiliation(s)
- Mayada Woriedh
- Department of Molecular Phytopathology and Genetics, Biocenter Klein Flottbek, University of Hamburg, Ohnhorststrasse 18, D-22609 Hamburg, Germany
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21
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Xu J, Zhang B, Jiang C, Ming F. RceIF5A, encoding an eukaryotic translation initiation factor 5A in Rosa chinensis, can enhance thermotolerance, oxidative and osmotic stress resistance of Arabidopsis thaliana. PLANT MOLECULAR BIOLOGY 2011; 75:167-78. [PMID: 21107886 DOI: 10.1007/s11103-010-9716-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2010] [Accepted: 11/15/2010] [Indexed: 05/04/2023]
Abstract
Eukaryotic translation initiation factor 5A (eIF5A) is the only cellular protein known to contain the unusual amino acid hypusine. It is a highly conserved protein found in all eukaryotic organisms. Although originally identified as a translation initiation factor, recent studies suggest that eIF5A is mainly involved in translation elongation, mRNA turnover and decay, cell proliferation, and programmed cell death. However, the precise cellular function of eIF5A remains largely unknown, especially in plants. Here, we report the identification and characterization of RceIF5A from Rosa chinensis. RceIF5A expression is up-regulated in Rosa chinensis under high temperature, and oxidative and osmotic stress conditions. We produced transgenic Arabidopsis that constitutively enhanced or suppressed expression of RceIF5A. The RceIF5A over-expression plants exhibited increased resistance to heat, and oxidative and osmotic stresses, while the suppressed expression plants (three AteIF5A isoforms in Arabidopsis were down-regulated) showed more susceptibility to these stresses. These results reveal a new physiological role for eIF5A in plants and contribute to the elucidation of the molecular mechanisms involved in the stress response pathway.
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Affiliation(s)
- Jianyao Xu
- State Key Laboratory of Genetic Engineering, Institute of Genetics, Fudan University, 220 Handan Road, Shanghai, 200433, People's Republic of China
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22
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Gomez-Jimenez MC, Paredes MA, Gallardo M, Sanchez-Calle IM. Mature fruit abscission is associated with up-regulation of polyamine metabolism in the olive abscission zone. JOURNAL OF PLANT PHYSIOLOGY 2010; 167:1432-41. [PMID: 20643493 DOI: 10.1016/j.jplph.2010.05.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2010] [Revised: 05/17/2010] [Accepted: 05/17/2010] [Indexed: 05/19/2023]
Abstract
This study investigates whether, and how, polyamines (PAs) are involved in mature fruit abscission of olive (Olea europaea L.). Physiological abscission was studied in relation to the activation of the abscission zone (AZ), located between fruit and peduncle, from two olive cultivars where the breakstrength profiles and the scanning electron micrographs illustrated differences in the abscission program, under natural conditions, of mature fruit. The localization and activities of diamine oxidase (DAO), polyamine oxidase (PAO) and PA biosynthetic enzymes, together with PA content were investigated in the fruit AZ during development and abscission. The activities of arginine decarboxylase and S-adenosyl-l-methionine decarboxylase in the fruit AZ were significantly increased and decreased, respectively, by mature fruit abscission, in good agreement with the rise in free putrescine (Put), and content in uncommon PAs there, such as homospermidine and cadaverine, while no significant differences in free spermidine (Spd) and spermine (Spm) contents were detected. By contrast, an abscission-induced decrease was noted in the contents of insoluble conjugated Put, Spd and Spm. The maximum activity of PAO coincided with the maximum content of Spd and Spm, and it was localized mainly in parenchyma cells of pith, while DAO was present mainly in parenchyma cells of pith and cortex as well as at the base of the vascular tissue. These results suggest a clear correlation between the PA distribution and mature fruit abscission. The regulation of PA metabolism is discussed in relation to mature fruit abscission.
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Affiliation(s)
- Maria C Gomez-Jimenez
- Department of Plant Physiology, University of Extremadura, Avda de Elvas s/n, 06006 Badajoz, Spain.
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23
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Ma Y, Miura E, Ham BK, Cheng HW, Lee YJ, Lucas WJ. Pumpkin eIF5A isoforms interact with components of the translational machinery in the cucurbit sieve tube system. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 64:536-50. [PMID: 20807213 DOI: 10.1111/j.1365-313x.2010.04347.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
In yeast, eIF5A, in combination with eEF2, functions at the translation step, during the protein elongation cycle. This result is of significance with respect to functioning of the enucleate sieve tube system, as eIF5A was recently detected in Cucurbita maxima (pumpkin) phloem sap. In the present study, we further characterized four CmeIF5A isoforms, encoding three proteins, all of which were present in the phloem sap. Although hypusination of CmeIF5A was not necessary for entry into the sieve elements, this unique post-translational modification was necessary for RNA binding. The two enzymes required for hypusination were detected in pumpkin phloem sap, where presumably this modification takes place. A combination of gel-filtration chromatography and protein overlay assays demonstrated that, as in yeast, CmeIF5A interacts with phloem proteins, like eEF2, known to be involved in protein synthesis. These findings are discussed in terms of a potential role for eIF5A in regulating protein synthesis within the enucleate sieve tube system of the angiosperms.
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Affiliation(s)
- Yi Ma
- Department of Plant Biology, College of Biological Sciences, University of California, Davis, CA 95616, USA
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24
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Ma F, Liu Z, Wang TW, Hopkins MT, Peterson CA, Thompson JE. Arabidopsis eIF5A3 influences growth and the response to osmotic and nutrient stress. PLANT, CELL & ENVIRONMENT 2010; 33:1682-96. [PMID: 20492553 DOI: 10.1111/j.1365-3040.2010.02173.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
AteIF5A3, one of three genes encoding eukaryotic translation initiation factor 5A (eIF5A) in Arabidopsis thaliana, and corresponding genes PdeIF5A3 from Populus deltoides (eastern cottonwood) and SleIF5A4 from Solanum lycopersicum (tomato) were constitutively over-expressed in A. thaliana. The resultant transgenic plants exhibited enhanced vegetative and reproductive growth. Indeed, the increase in seed yield relative to empty vector controls for the PdeIF5A3 over-expressing plants ranged from 50% to 300% depending on the line. The PdeIF5A3 over-expressing plants also exhibited enhanced fitness when exposed to osmotic and nutrient (N, P and K) stress. The spatial localization of AteIF5A3 was visualized by confocal microscopy using transgenic plants expressing P(AteIF5A3) :GFP-AteIF5A3. GFP fluorescence reflecting expression of AteIF5A3 was detectable in the phloem, particularly companion cells, of roots, stems and leaves, in the epidermal cells of the root tip, in the columella cells of the root cap and in the chalazal tissue of fertilized ovules, which all play a pivotal role in nutrient or hormone translocation. Thus, AteIF5A3 appears to be involved in supporting growth and to play a regulatory role in the response of plants to sub-lethal osmotic and nutrient stress.
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Affiliation(s)
- Fengshan Ma
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
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25
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Zhang M, Li G, Huang W, Bi T, Chen G, Tang Z, Su W, Sun W. Proteomic study of Carissa spinarum
in response to combined heat and drought stress. Proteomics 2010; 10:3117-29. [DOI: 10.1002/pmic.200900637] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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26
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Carvajal-Gamez B, Arroyo R, Lira R, López-Camarillo C, Alvarez-Sánchez ME. Identification of two novel Trichomonas vaginalis eif-5a genes. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2010; 10:284-91. [PMID: 20060503 DOI: 10.1016/j.meegid.2009.12.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2009] [Revised: 12/17/2009] [Accepted: 12/25/2009] [Indexed: 11/19/2022]
Abstract
The eukaryotic translation initiation factor 5A (eIF-5A) is highly conserved and is the only protein that is known to contain the unique and essential amino acid residue hypusine. Synthesis of hypusine is essential for the function of eIF5A in eukaryotic cell proliferation and survival. In this study, we identified two novel eukaryotic translation initiation factor 5A (eIF-5A) genes in Trichomonas vaginalis. The tveif-5a1 and tveif-5a2 putative genes were localized in different contigs, both containing ORFs encoding proteins of 168 amino acids that share high sequence identity with eIF-5A sequences from other eukaryotic organisms. A phylogenetic tree constructed with TveIF-5A1 and TveIF-5A2 from T. vaginalis and 13 other eIF-5A sequences of eukaryotic and archaebacterial origin revealed that both trichomonal TveIF-5As show the highest degree of similarity to bacteria. Using an anti-TveIF-5A antibody, we detected two protein bands and spots of 19 and 20kDa with isoelectric points (pI) of 5.2 and 5.5, respectively, by one and two-dimensional Western blot assays. In addition, we used reverse transcription polymerase chain reaction (RT-PCR) to demonstrate that both of these tveif-5a genes are expressed in T. vaginalis. Immunofluorescence assays showed that the TveIF-5A protein was dispersed throughout the parasite cytoplasm. In conclusion, T. vaginalis has two eif-5a genes, and both genes are expressed as highly conserved proteins of 19kDa, which are localized in the cytoplasm of this parasite.
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Affiliation(s)
- B Carvajal-Gamez
- Posgrado en Ciencias Genómicas, Universidad Autónoma de la Ciudad de México (UACM). San Lorenzo # 290, Col. Del Valle, CP 03100 Mexico City, Mexico
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27
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Alam I, Lee DG, Kim KH, Park CH, Sharmin SA, Lee H, Oh KW, Yun BW, Lee BH. Proteome analysis of soybean roots under waterlogging stress at an early vegetative stage. J Biosci 2010; 35:49-62. [PMID: 20413909 DOI: 10.1007/s12038-010-0007-5] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
To gain better insight into how soybean roots respond to waterlogging stress, we carried out proteomic profiling combined with physiological analysis at two time points for soybean seedlings in their early vegetative stage. Seedlings at the V2 stage were subjected to 3 and 7 days of waterlogging treatments. Waterlogging stress resulted in a gradual increase of lipid peroxidation and in vivo H2O2 level in roots. Total proteins were extracted from root samples and separated by two-dimensional gel electrophoresis (2-DE). A total of 24 reproducibly resolved, differentially expressed protein spots visualized by Coomassie brilliant blue (CBB) staining were identified by matrix assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry or electrospray ionization tandem mass spectrometry (ESI-MS/MS) analysis. Of these, 14 proteins were upregulated; 5 proteins were decreased; and 5 were newly induced in waterlogged roots. The identified proteins include well-known classical anaerobically induced proteins as well as novel waterlogging-responsive proteins that were not known previously as being waterlogging responsive. The novel proteins are involved in several processes, i.e. signal transduction, programmed cell death, RNA processing, redox homeostasis and metabolisms of energy. An increase in abundance of several typical anaerobically induced proteins, such as glycolysis and fermentation pathway enzymes, suggests that plants meet energy requirement via the fermentation pathway due to lack of oxygen. Additionally, the impact of waterlogging on the several programmed cell death- and signal transduction-related proteins suggest that they have a role to play during stress. RNA gel blot analysis for three programmed cell death-related genes also revealed a differential mRNA level but did not correlate well with the protein level. These results demonstrate that the soybean plant can cope with waterlogging through the management of carbohydrate consumption and by regulating programmed cell death. The identification of novel proteins such as a translation initiation factor, apyrase, auxin-amidohydrolase and coproporphyrinogen oxidase in response to waterlogging stress may provide new insight into the molecular basis of the waterlogging-stress response of soybean.
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Affiliation(s)
- Iftekhar Alam
- Division of Applied Life Science (BK21 Program), IALS, PMBBRC, Gyeongsang National University, Jinju 660-701, Korea
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Łebska M, Ciesielski A, Szymona L, Godecka L, Lewandowska-Gnatowska E, Szczegielniak J, Muszyńska G. Phosphorylation of maize eukaryotic translation initiation factor 5A (eIF5A) by casein kinase 2: identification of phosphorylated residue and influence on intracellular localization of eIF5A. J Biol Chem 2010; 285:6217-26. [PMID: 20018887 PMCID: PMC2825417 DOI: 10.1074/jbc.m109.018770] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Revised: 12/15/2009] [Indexed: 11/06/2022] Open
Abstract
Maize eukaryotic translation initiation factor 5A (ZmeIF5A) co-purifies with the catalytic alpha subunit of protein kinase CK2 and is phosphorylated by this enzyme. Phosphorylated ZmeIF5A was also identified after separation of maize leaf proteins by two-dimensional electrophoresis. Multiple sequence alignment of eIF5A proteins showed that in monocots, in contrast to other eukaryotes, there are two serine/threonine residues that could potentially be phosphorylated by CK2. To identify the phosphorylation site(s) of ZmeIF5A, the serine residues potentially phosphorylated by CK2 were mutated. ZmeIF5A and its mutated variants S2A and S4A were expressed in Escherichia coli and purified. Of these recombinant proteins, only ZmeIF5A-S2A was not phosphorylated by maize CK2. Also, Arabidopsis thaliana and Saccharomyces cerevisiae eIF5A-S2A mutants were not phosphorylated despite effective phosphorylation of wild-type variants. A newly developed method exploiting the specificity of thrombin cleavage was used to confirm that Ser(2) in ZmeIF5A is indeed phosphorylated. To find a role of the Ser(2) phosphorylation, ZmeIF5A and its variants mutated at Ser(2) (S2A and S2D) were transiently expressed in maize protoplasts. The expressed fluorescence labeled proteins were visualized by confocal microscopy. Although wild-type ZmeIF5A and its S2A variant were distributed evenly between the nucleus and cytoplasm, the variant with Ser(2) replaced by aspartic acid, which mimics a phosphorylated serine, was sequestered in the nucleus. These results suggests that phosphorylation of Ser(2) plays a role in regulation of nucleocytoplasmic shuttling of eIF5A in plant cells.
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Affiliation(s)
- Maja Łebska
- From the Institute of Biochemistry and Biophysics, Polish Academy of Science, Pawińskiego 5a, 02-106 Warsaw, Poland
| | - Arkadiusz Ciesielski
- From the Institute of Biochemistry and Biophysics, Polish Academy of Science, Pawińskiego 5a, 02-106 Warsaw, Poland
| | - Lidia Szymona
- From the Institute of Biochemistry and Biophysics, Polish Academy of Science, Pawińskiego 5a, 02-106 Warsaw, Poland
| | - Luiza Godecka
- From the Institute of Biochemistry and Biophysics, Polish Academy of Science, Pawińskiego 5a, 02-106 Warsaw, Poland
| | | | - Jadwiga Szczegielniak
- From the Institute of Biochemistry and Biophysics, Polish Academy of Science, Pawińskiego 5a, 02-106 Warsaw, Poland
| | - Grażyna Muszyńska
- From the Institute of Biochemistry and Biophysics, Polish Academy of Science, Pawińskiego 5a, 02-106 Warsaw, Poland
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29
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Bianco L, Lopez L, Scalone AG, Di Carli M, Desiderio A, Benvenuto E, Perrotta G. Strawberry proteome characterization and its regulation during fruit ripening and in different genotypes. J Proteomics 2009; 72:586-607. [DOI: 10.1016/j.jprot.2008.11.019] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2008] [Revised: 10/08/2008] [Accepted: 11/24/2008] [Indexed: 11/17/2022]
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Valcu CM, Lalanne C, Plomion C, Schlink K. Heat induced changes in protein expression profiles of Norway spruce (Picea abies) ecotypes from different elevations. Proteomics 2009; 8:4287-302. [PMID: 18814337 DOI: 10.1002/pmic.200700992] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Although tree species typically exhibit low genetic differentiation between populations, ecotypes adapted to different environmental conditions can vary in their capacity to withstand and recover from environmental stresses like heat stress. Two month old seedlings of a Picea abies ecotype adapted to high elevation showed lower level of thermotolerance and higher level of tolerance to oxidative stress relative to a low elevation ecotype. Protein expression patterns following exposure to severe heat stress of the two ecotypes were compared by means of 2-DE. Several proteins exhibiting ecotype and tissue specific expression were identified by MS/MS. Among them, small heat shock proteins of the HSP 20 family and proteins involved in protection from oxidative stress displayed qualitative and quantitative differences in expression between the ecotypes correlated with the observed phenotypic differences. On the basis of these results, it can be speculated that the observed interpopulation polymorphism of protein regulation in response to heat stress could underlie their different capacities to withstand and recover from heat stress. These local adaptations are potentially relevant for the species adaptation to the conditions predicted by the current models for climate change.
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Affiliation(s)
- Cristina-Maria Valcu
- Section of Forest Genetics, Technische Universität München, Freising-Weihenstephan, Germany.
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31
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Huang JK, Cui Y, Chen CH, Clampitt D, Lin CT, Wen L. Molecular cloning and functional expression of bovine deoxyhypusine hydroxylase cDNA and homologs. Protein Expr Purif 2007; 54:126-33. [PMID: 17391984 PMCID: PMC1945118 DOI: 10.1016/j.pep.2007.02.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2007] [Revised: 02/13/2007] [Accepted: 02/14/2007] [Indexed: 11/20/2022]
Abstract
Deoxyhypusine hydroxylase is the second of the two enzymes that catalyzes the maturation of eukaryotic initiation factor 5A (eIF5A). The mature eIF5A is the only known protein in eukaryotic cells that contains the unusual amino acid hypusine (N(epsilon)-(4-amino-2(R)-hydroxybutyl)lysine). Synthesis of hypusine is essential for the function of eIF5A in eukaryotic cell proliferation and survival. Here, we describe the cloning and characterization of bovine deoxyhypusine hydroxylase cDNA and its homologs. The deduced bovine deoxyhypusine hydroxylase protein is 87% identical to human enzyme and 45% identical to yeast enzyme. The overexpressed enzyme showed activity in catalyzing the hydroxylation of the deoxyhypusine residue in the eIF5A intermediate. An amino acid substitution from Glu 57 to Gly located at one of the four conserved His-Glu (HE) pairs, the potential metal coordination sites, resulted in severe reduction of deoxyhypusine hydroxylase activity. A deletion at the HEAT-repeats 1-3 resulted in complete losses of deoxyhypusine hydroxylase activity.
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Affiliation(s)
- Jenq-Kuen Huang
- Department of Chemistry, Western Illinois University, 1 University Circle, Macomb, IL 61455-1390
| | - Yalun Cui
- Department of Chemistry, Western Illinois University, 1 University Circle, Macomb, IL 61455-1390
| | - Chieh-Hua Chen
- Department of Chemistry, Western Illinois University, 1 University Circle, Macomb, IL 61455-1390
| | - Denae Clampitt
- Department of Chemistry, Western Illinois University, 1 University Circle, Macomb, IL 61455-1390
| | - Chi-Tsai Lin
- Institute of Bioscience and Biotechnology, National Taiwan Ocean University, Keelung, Taiwan 202
| | - Lisa Wen
- Department of Chemistry, Western Illinois University, 1 University Circle, Macomb, IL 61455-1390
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32
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Duguay J, Jamal S, Liu Z, Wang TW, Thompson JE. Leaf-specific suppression of deoxyhypusine synthase in Arabidopsis thaliana enhances growth without negative pleiotropic effects. JOURNAL OF PLANT PHYSIOLOGY 2007; 164:408-20. [PMID: 16600425 DOI: 10.1016/j.jplph.2006.02.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2005] [Accepted: 02/10/2006] [Indexed: 05/08/2023]
Abstract
Deoxyhypusine synthase (DHS) mediates the first of two enzymatic reactions required for the post-translational activation of eukaryotic translation initiation factor 5A (eIF5A), which in turn is thought to facilitate translation of specific mRNAs. Analyses of GUS activity in transgenic Arabidopsis plants expressing the GUS reporter gene under regulation of the promoter for AtDHS revealed that the expression of DHS changes both spatially and temporally as development progresses. In particular, DHS is expressed not only in rosette leaves, but also in the anthers of developing flowers. To determine the role of DHS in leaves, transgenic plants in which DHS was selectively suppressed in rosettes of Arabidopsis plants were prepared. This was achieved by expressing AtDHS 3'-UTR cDNA as a transgene under regulation of the promoter for AtRbcS2, a gene encoding the small subunit of Rubisco. The dominant phenotypic traits of the DHS-suppressed plants proved to be a dramatic enhancement of both vegetative and reproductive growth. As well, the onset of leaf senescence in the DHS-suppressed plants was delayed by approximately 1 week, but there was no change in the timing of bolting. In addition, there was no evidence for the negative pleiotropic effects, including stunted reproductive growth and reduced seed yield, noted previously for transgenic plants in which DHS was constitutively suppressed. The results indicate that DHS plays a pivotal role in both growth and senescence.
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Affiliation(s)
- Jeremy Duguay
- Department of Biology, University of Waterloo, Waterloo, Ont, Canada
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33
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Hopkins M, Taylor C, Liu Z, Ma F, McNamara L, Wang TW, Thompson JE. Regulation and execution of molecular disassembly and catabolism during senescence. THE NEW PHYTOLOGIST 2007; 175:201-214. [PMID: 17587370 DOI: 10.1111/j.1469-8137.2007.02118.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Senescence is a highly orchestrated developmental stage in the life cycle of plants. The onset of senescence is tightly controlled by signaling cascades that initiate changes in gene expression and the synthesis of new proteins. This complement of new proteins includes hydrolytic enzymes capable of executing catabolism of macromolecules, which in turn sets in motion disassembly of membrane molecular matrices, leading to loss of cell function and, ultimately, complete breakdown of cellular ultrastructure. A distinguishing feature of senescence that sets it apart from other types of programmed cell death is the recovery of carbon and nitrogen from the dying tissue and their translocation to growing parts of the plant such as developing seeds. For this to be accomplished, the initiation of senescence and its execution have to be meticulously regulated. For example, the initiation of membrane disassembly has to be intricately linked with the recruitment of nutrients because their ensuing translocation out of the senescing tissue requires functional membranes. Molecular mechanisms underlying this linkage and its integration with the catabolism of macromolecules in senescing tissues are addressed.
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Affiliation(s)
- Marianne Hopkins
- Department of Biology, University of Waterloo, Waterloo, ONT Canada N2L 3G1
| | - Catherine Taylor
- Department of Biology, University of Waterloo, Waterloo, ONT Canada N2L 3G1
| | - Zhongda Liu
- Department of Biology, University of Waterloo, Waterloo, ONT Canada N2L 3G1
| | - Fengshan Ma
- Department of Biology, University of Waterloo, Waterloo, ONT Canada N2L 3G1
| | - Linda McNamara
- Department of Biology, University of Waterloo, Waterloo, ONT Canada N2L 3G1
| | - Tzann-Wei Wang
- Department of Biology, University of Waterloo, Waterloo, ONT Canada N2L 3G1
| | - John E Thompson
- Department of Biology, University of Waterloo, Waterloo, ONT Canada N2L 3G1
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Schrader R, Young C, Kozian D, Hoffmann R, Lottspeich F. Temperature-sensitive eIF5A mutant accumulates transcripts targeted to the nonsense-mediated decay pathway. J Biol Chem 2006; 281:35336-46. [PMID: 16987817 DOI: 10.1074/jbc.m601460200] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The highly conserved protein eIF5A found in Archaea and all eukaryotes uniquely contains the posttranslationally formed amino acid hypusine. Despite being essential the functions of this protein and its modification remain unclear. To gain more insight into these functions temperature-sensitive mutants of the human EIF5A1 were characterized in the yeast Saccharomyces cerevisiae. Expression of the point mutated form V81G in a DeltaeIF5A strain of yeast led to a strongly temperature-sensitive phenotype and to a significantly reduced protein level at restrictive temperature. The mutant showed accumulation of a subset of mRNAs that was also observed in nonsense-mediated decay (NMD)-deficient yeast strains. After short incubation at restrictive temperature the mutant exhibited increased half-lives of the intron containing CYH2 pre-mRNA and mature transcripts of NMD-dependent genes. Reduced telomere silencing and shortening was detected in the V81G mutant further supporting similarities to NMD-deficient strains. Our data suggest that eIF5A mediates important cellular processes like cell viability and senescence through its effects on the stability of certain mRNAs.
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Affiliation(s)
- Rainer Schrader
- Department for Protein Analytics, Max Planck Institute for Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.
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35
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Hongzhi W, Rongcai M, Ruifen L, Guoying W, Jianhua W. Virus-induced silencing of a tobacco deoxyhypusine synthase gene. CHINESE SCIENCE BULLETIN-CHINESE 2005. [DOI: 10.1007/bf02899640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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36
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Wang TW, Zhang CG, Wu W, Nowack LM, Madey E, Thompson JE. Antisense suppression of deoxyhypusine synthase in tomato delays fruit softening and alters growth and development. PLANT PHYSIOLOGY 2005; 138:1372-82. [PMID: 15951486 PMCID: PMC1176410 DOI: 10.1104/pp.105.060194] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The effects of suppressing deoxyhypusine synthase (DHS) have been examined in tomato (Solanum lycopersicum cv UCT5). DHS mediates the first of two sequential enzymatic reactions that activate eukaryotic translation initiation factor-5A (eIF-5A) by converting a conserved Lys to the unusual amino acid, deoxyhypusine. DHS protein levels were suppressed in transgenic plants by expressing the 3'-untranslated region of tomato DHS under regulation of the constitutive cauliflower mosaic virus promoter. Fruit from the transgenic plants ripened normally, but exhibited delayed postharvest softening and senescence that correlated with suppression of DHS protein levels. Northern-blot analysis indicated that all four gene family members of tomato eIF-5A are expressed in fruit, and that three are up-regulated in parallel with enhancement of DHS mRNA as the fruit begin to senesce and soften. Transgenic plants in which DHS was more strongly suppressed were male sterile, did not produce fruit, and had larger, thicker leaves with enhanced levels of chlorophyll. The activity of PSII was 2 to 3 times higher in these transgenic leaves than in corresponding leaves of wild-type plants, and there was also enhanced deposition of starch in the stems. The data collectively indicate that suppression of DHS has pleiotropic effects on growth and development of tomato. This may, in turn, reflect the fact that there is a single DHS gene in tomato and that its cognate protein is involved in the activation of four distinct isoforms of eIF-5A.
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Affiliation(s)
- Tzann-Wei Wang
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
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37
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Moyle R, Fairbairn DJ, Ripi J, Crowe M, Botella JR. Developing pineapple fruit has a small transcriptome dominated by metallothionein. JOURNAL OF EXPERIMENTAL BOTANY 2005; 56:101-112. [PMID: 15520025 DOI: 10.1093/jxb/eri015] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In a first step toward understanding the molecular basis of pineapple fruit development, a sequencing project was initiated to survey a range of expressed sequences from green unripe and yellow ripe fruit tissue. A highly abundant metallothionein transcript was identified during library construction, and was estimated to account for up to 50% of all EST library clones. Library clones with metallothionein subtracted were sequenced, and 408 unripe green and 1140 ripe yellow edited EST clone sequences were retrieved. Clone redundancy was high, with the combined 1548 clone sequences clustering into just 634 contigs comprising 191 consensus sequences and 443 singletons. Half of the EST clone sequences clustered within 13.5% and 9.3% of contigs from green unripe and yellow ripe libraries, respectively, indicating that a small subset of genes dominate the majority of the transcriptome. Furthermore, sequence cluster analysis, northern analysis, and functional classification revealed major differences between genes expressed in the unripe green and ripe yellow fruit tissues. Abundant genes identified from the green fruit include a fruit bromelain and a bromelain inhibitor. Abundant genes identified in the yellow fruit library include a MADS box gene, and several genes normally associated with protein synthesis, including homologues of ribosomal L10 and the translation factors SUI1 and eIF5A. Both the green unripe and yellow ripe libraries contained high proportions of clones associated with oxidative stress responses and the detoxification of free radicals.
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Affiliation(s)
- Richard Moyle
- Plant Genetic Engineering Laboratory, Department of Botany, University of Queensland, QLD 4072, Australia
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38
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Anke S, Niemüller D, Moll S, Hänsch R, Ober D. Polyphyletic origin of pyrrolizidine alkaloids within the Asteraceae. Evidence from differential tissue expression of homospermidine synthase. PLANT PHYSIOLOGY 2004; 136:4037-47. [PMID: 15557091 PMCID: PMC535835 DOI: 10.1104/pp.104.052357] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The evolution of pathways within plant secondary metabolism has been studied by using the pyrrolizidine alkaloids (PAs) as a model system. PAs are constitutively produced by plants as a defense against herbivores. The occurrence of PAs is restricted to certain unrelated families within the angiosperms. Homospermidine synthase (HSS), the first specific enzyme in the biosynthesis of the necine base moiety of PAs, was originally recruited from deoxyhypusine synthase, an enzyme involved in the posttranslational activation of the eukaryotic initiation factor 5A. Recently, this gene recruitment has been shown to have occurred several times independently within the angiosperms and even twice within the Asteraceae. Here, we demonstrate that, within these two PA-producing tribes of the Asteraceae, namely Senecioneae and Eupatorieae, HSS is expressed differently despite catalyzing the same step in PA biosynthesis. Within Eupatorium cannabinum, HSS is expressed uniformly in all cells of the root cortex parenchyma, but not within the endodermis and exodermis. Within Senecio vernalis, HSS expression has been previously identified in groups of specialized cells of the endodermis and the adjacent root cortex parenchyma. This expression pattern was confirmed for Senecio jacobaea as well. Furthermore, the expression of HSS in E. cannabinum is dependent on the development of the plant, suggesting a close linkage to plant growth.
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Affiliation(s)
- Sven Anke
- Institut für Pharmazeutische Biologie der Technischen Universität, D-38106 Braunschweig, Germany
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39
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Reimann A, Nurhayati N, Backenköhler A, Ober D. Repeated evolution of the pyrrolizidine alkaloid-mediated defense system in separate angiosperm lineages. THE PLANT CELL 2004; 16:2772-84. [PMID: 15466410 PMCID: PMC520970 DOI: 10.1105/tpc.104.023176] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Species of several unrelated families within the angiosperms are able to constitutively produce pyrrolizidine alkaloids as a defense against herbivores. In pyrrolizidine alkaloid (PA) biosynthesis, homospermidine synthase (HSS) catalyzes the first specific step. HSS was recruited during angiosperm evolution from deoxyhypusine synthase (DHS), an enzyme involved in the posttranslational activation of eukaryotic initiation factor 5A. Phylogenetic analysis of 23 cDNA sequences coding for HSS and DHS of various angiosperm species revealed at least four independent recruitments of HSS from DHS: one within the Boraginaceae, one within the monocots, and two within the Asteraceae family. Furthermore, sequence analyses indicated elevated substitution rates within HSS-coding sequences after each gene duplication, with an increased level of nonsynonymous mutations. However, the contradiction between the polyphyletic origin of the first enzyme in PA biosynthesis and the structural identity of the final biosynthetic PA products needs clarification.
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Affiliation(s)
- Andreas Reimann
- Institut für Pharmazeutische Biologie der Technischen Universität, 38106 Braunschweig, Germany
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40
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Molitor IM, Knöbel S, Dang C, Spielmann T, Alléra A, König GM. Translation initiation factor eIF-5A from Plasmodium falciparum. Mol Biochem Parasitol 2004; 137:65-74. [PMID: 15279952 DOI: 10.1016/j.molbiopara.2004.04.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2004] [Revised: 04/07/2004] [Accepted: 04/23/2004] [Indexed: 10/26/2022]
Abstract
Eukaryotic translation initiation factor (eIF-5A) is a highly conserved and essential protein that contains the unique amino acid hypusine. The first step in the post-translational biosynthesis of hypusine, the transfer of an aminobutyl moiety from the polyamine substrate spermidine to the -amino group of a specific lysine residue in the eIF-5A precursor, is catalyzed by the enzyme deoxyhypusine synthase. A cDNA encoding a protein homologous to eIF-5A was isolated by plaque hybridization from a cDNA library of Plasmodium falciparum. The cloned cDNA contains an open reading frame encoding a protein of 161 amino acids, which shares a high sequence identity with other eukaryotic eIF-5A sequences. A phylogenetic tree constructed with eIF-5A from P. falciparum and 16 other eIF-5A sequences of eukaryotic and archaeal origin reveals that plasmodial eIF-5A together with other apicomplexan eIF-5A show a higher degree of homology to plant proteins than to animal and fungal sequences. The plasmodial eIF-5A gene was expressed as a six-histidine tagged fusion protein in Escherichia coli. Radioactive incorporation studies with [1,8-3H] spermidine indicated that this protein can serve as a substrate for human deoxyhypusine synthase. Results of quantitative real-time PCR studies with synchronized erythrocytic stages of P. falciparum revealed no significant induction or downregulation but only some variation in the expression level of plasmodial eIF-5A in ring, trophozoite and schizont stage.
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Affiliation(s)
- Ilka M Molitor
- Department of Pharmaceutical Biology, University of Bonn, Nussallee 6, D-53115, Germany.
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41
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Lo M, Taylor C, Wang L, Nowack L, Wang TW, Thompson J. Characterization of an ultraviolet B-induced lipase in Arabidopsis. PLANT PHYSIOLOGY 2004; 135:947-58. [PMID: 15181214 PMCID: PMC514129 DOI: 10.1104/pp.103.036376] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2003] [Revised: 01/29/2004] [Accepted: 01/30/2004] [Indexed: 05/24/2023]
Abstract
An Arabidopsis expressed sequence tag clone, 221D24, encoding a lipase has been characterized using an antisense approach. The lipase gene is expressed during normal growth and development of Arabidopsis rosette leaves but is down-regulated as the leaves senesce. When plants are exposed to sublethal levels of UV-B radiation, expression of the lipase is strongly up-regulated. The lipase protein is localized in the cell cytosol and is present in all organs of Arabidopsis plants. Recombinant lipase protein produced in Escherichia coli preferentially hydrolyzed phospholipids, indicating that the gene encodes a phospholipase. Transgenic plants in which lipase expression is suppressed showed enhanced tolerance to UV-B stress but not osmotic stress and were unable to up-regulate PR-1 expression when irradiated with UV-B. The observations collectively indicate that the lipase is capable of deesterifying membrane phospholipids and is up-regulated in response to UV-B irradiation.
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Affiliation(s)
- Maisie Lo
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
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42
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Chou WC, Huang YW, Tsay WS, Chiang TY, Huang DD, Huang HJ. Expression of genes encoding the rice translation initiation factor, eIF5A, is involved in developmental and environmental responses. PHYSIOLOGIA PLANTARUM 2004; 121:50-57. [PMID: 15086817 DOI: 10.1111/j.0031-9317.2004.00292.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Eukaryotic translation initiation factor 5 A (eIF5A) is the only cellular protein known to contain the unusual amino acid hypusine. However, the precise cellular function of eIF5A is to date unknown. In the present study, we report on the characterization of two cDNA clones encoding eIF5A in rice (Oryza sativa). Sequence analysis revealed that the two cDNAs share 93% amino acid sequence identity. Phylogenetic analysis of the eIF5A genes revealed paraphyly of OseIF5A-1 and OseIF5A-2. Analysis at the mRNA level has shown that OseIF5A-1 and OseIF5A-2 are expressed in rice leaves and panicles and high relative amounts of both genes were detected in old leaves. In addition, both OseIF5A-1 and OseIF5A-2 were spatially regulated during rice leaf development. In suspension-cultured cells, the transcripts of OseIF5A genes were strongly reduced after sugar starvation. Abiotic stresses, salt and heavy metal, induce the accumulation of OseIF5A-1 and OseIF5A-2 mRNAs in rice cells. These results suggested that both OseIF5A genes might be regulated by plant development and environmental stresses.
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Affiliation(s)
- Wan-Chi Chou
- Department of Biology, Center for Biosciences and Biotechology, National Cheng Kung University, Tainan 701, Taiwan
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Huang JK, Tsai S, Huang GH, Gowda PG, Walzer AM, Wen L. Higher activity of recombinant bovine deoxyhypusine synthase vs. human deoxyhypusine synthase. Protein Expr Purif 2004; 35:32-8. [PMID: 15039063 DOI: 10.1016/j.pep.2003.12.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2003] [Revised: 11/25/2003] [Indexed: 10/26/2022]
Abstract
Mature eukaryotic initiation factor 5A (eIF5A) is the only known protein in eukaryotic cells that contains the unusual amino acid hypusine (Nepsilon-(4-amino-2(R)-hydroxybutyl)lysine). The synthesis of hypusine is essential for the function of eIF5A in eukaryotic cell proliferation and survival. Deoxyhypusine synthase is the first of the two enzymes that catalyzes the maturation of eIF5A. We have subcloned the cDNA encoding bovine and human deoxyhypusine synthase into a pET-11a expression vector, separately. T7-tagged bovine and human deoxyhypusine synthase have been overexpressed in Escherichia coli and purified to homogeneity using T7 antibody affinity chromatography. Activities of the enzyme from both human and bovine have been measured by their ability to convert the eIF5A precursor protein to the intermediate, deoxyhypusine form of eIF5A. Our results have shown that bovine deoxyhypusine synthase has considerably higher activity than human deoxyhypusine synthase in catalyzing the synthesis of deoxyhypusine.
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Affiliation(s)
- Jenq-Kuen Huang
- Department of Chemistry, Western Illinois University, One University Circle, Macomb, IL 61455, USA
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44
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Thompson JE, Hopkins MT, Taylor C, Wang TW. Regulation of senescence by eukaryotic translation initiation factor 5A: implications for plant growth and development. TRENDS IN PLANT SCIENCE 2004; 9:174-9. [PMID: 15063867 DOI: 10.1016/j.tplants.2004.02.008] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Regulation of protein synthesis is increasingly being recognized as an important determinant of cell proliferation and senescence. In particular, recent evidence indicates that eukaryotic translation initiation factor 5A (eIF-A) plays a pivotal role in this determination. Separate isoforms of eIF-5A appear to facilitate the translation of mRNAs required for cell division and cell death. This raises the possibility that eIF-5A isoforms are elements of a biological switch that is in one position in dividing cells and in another position in dying cells. Changes in the position of this putative switch in response to physiological and environmental cues are likely to have a significant impact on plant growth and development.
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Affiliation(s)
- John E Thompson
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.
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45
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Huang JK, Tsai S, Huang GH, Sershon VC, Alley AM, Wen L. Molecular cloning of bovine eIF5A and deoxyhypusine synthase cDNA. DNA SEQUENCE : THE JOURNAL OF DNA SEQUENCING AND MAPPING 2004; 15:26-32. [PMID: 15354351 DOI: 10.1080/10425170310001652174] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Deoxyhypusine synthase is the first of the two enzymes that catalyzes the maturation of eukaryotic initiation factor 5A (eIF5A). The mature eIF5A is the only known protein in eukaryotic cells that contains the unusual amino acid hypusine (N(epsilon)-(4-amino-2(R)-hydroxybutyl)-lysine). Synthesis of hypusine is essential for the function of eIF5A in eukaryotic cell proliferation and survival. Here we describe the cloning and characterization of bovine eIF5A and bovine deoxyhypusine synthase. The deduced bovine eIF5A protein is 100% identical to human eIF5A-1, and the deduced bovine deoxyhypusine synthase protein showed a 93% identity to the human protein.
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Affiliation(s)
- Jenq-Kuen Huang
- Department of Chemistry, One University Circle, Western Illinois University, Macomb, IL 61455, USA
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46
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Kaiser A, Gottwald A, Maier W, Seitz HM. Targeting enzymes involved in spermidine metabolism of parasitic protozoa--a possible new strategy for anti-parasitic treatment. Parasitol Res 2003; 91:508-16. [PMID: 14530966 DOI: 10.1007/s00436-003-0970-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2003] [Accepted: 07/25/2003] [Indexed: 10/26/2022]
Abstract
Sequencing data obtained from the Plasmodium, Anopheles gambiae and human genome projects provide a new basis for drug and vaccine development. One of the most characteristic features in the process of drug development against parasitic protozoa is target identification in a biological pathway. The next step must be a structure-based rational drug design if the target is not only present in the parasite. In mouse models of malaria, such drugs should be tested for efficacy of the new therapies. Here, we present data that pinpoint the existence of two enzymes of the polyamine pathway involved in spermidine metabolism in P. falciparum, i.e. deoxyhypusine synthase (DHS; EC 1.1.1.249) and homospermidine synthase (HSS; EC 2.5.1.45). Recent data obtained from the malaria genome databases showed that at least a putative gene encoding DHS is present in the parasite. Sequencing data from the P. falciparum genome project prove that the eukaryotic initiation factor eIF5A (the substrate for DHS) exists in P. falciparum. Here, we present the amino acid sequence of eIF5A from P. vivax, which causes tertiary malaria. EIF5A from P. vivax shows 82% nucleic acid and 97% amino acid identity to its homologue from P. falciparum. GC/MS data and inhibitor studies with agmatine prove that the triamine homospermidine occurs in the parasite. These data suggest a separate locus encoding HSS in P. falciparum. The hss gene recruits from the dhs gene in eukaryotes. Here, we present genomic DNA fragments obtained by amplification with primers of a conserved region (amino acid positions 550-1,043) between the putative P. falciparum DHS gene ( dhs) and the HSS gene ( hss) from the plant Senecio vulgaris (Asteraceae). The amplification product from different P. falciparum strains reveals differences in sequence identity, compared with the putative dhs gene from P. falciparum strain 3D7. Expression of the full-length clone and determination of HSS-specific activity will finally prove whether a separate region encoding HSS exists.
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Affiliation(s)
- A Kaiser
- Institute for Medical Parasitology, Sigmund-Freud-Strasse 25, 53105, Bonn, Germany.
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Park JH, Wolff EC, Folk JE, Park MH. Reversal of the deoxyhypusine synthesis reaction. Generation of spermidine or homospermidine from deoxyhypusine by deoxyhypusine synthase. J Biol Chem 2003; 278:32683-91. [PMID: 12788913 DOI: 10.1074/jbc.m304247200] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Deoxyhypusine synthase catalyzes the first step in hypusine (N epsilon-(4-amino-2-hydroxybutyl)lysine) synthesis in a single cellular protein, eIF5A precursor. The synthesis of deoxyhypusine catalyzed by this enzyme involves transfer of the 4-aminobutyl moiety of spermidine to a specific lysine residue in the eIF5A precursor protein to form a deoxyhypusine-containing eIF5A intermediate, eIF5A(Dhp). We recently discovered the efficient reversal of deoxyhypusine synthesis. When eIF5A([3H]Dhp), radiolabeled in the 4-aminobutyl portion of its deoxyhypusine residue, was incubated with human deoxyhypusine synthase, NAD, and 1,3-diaminopropane, [3H]spermidine was formed by a rapid transfer of the radiolabeled 4-aminobutyl side chain of the [3H]deoxyhypusine residue to 1,3-diaminopropane. No reversal was observed with [3H]hypusine protein, suggesting that hydroxylation at the 4-aminobutyl side chain of the deoxyhypusine residue prevents deoxyhypusine synthase-mediated reversal of the modification. Purified human deoxyhypusine synthase also exhibited homospermidine synthesis activity when incubated with spermidine, NAD, and putrescine. Thus it was found that [14C]putrescine can replace eIF5A precursor protein as an acceptor of the 4-aminobutyl moiety of spermidine to form radiolabeled homospermidine. The Km value for putrescine (1.12 mM) as a 4-aminobutyl acceptor, however, is much higher than that for eIF5A precursor (1.5 microM). Using [14C]putrescine as an acceptor, various spermidine analogs were evaluated as donor substrates for human deoxyhypusine synthase. Comparison of spermidine analogs as inhibitors of deoxyhypusine synthesis, as donor substrates for synthesis of deoxyhypusine (or its analog), and for synthesis of homospermidine (or its analog) provides new insights into the intricate specificity of this enzyme and versatility of the deoxyhypusine synthase reaction.
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Affiliation(s)
- Jong-Hwan Park
- Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland 20892, USA
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Ober D, Harms R, Witte L, Hartmann T. Molecular evolution by change of function. Alkaloid-specific homospermidine synthase retained all properties of deoxyhypusine synthase except binding the eIF5A precursor protein. J Biol Chem 2003; 278:12805-12. [PMID: 12562768 DOI: 10.1074/jbc.m207112200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Deoxyhypusine synthase participates in the post-translational activation of the eukaryotic initiation factor 5A (eIF5A). The enzyme transfers the aminobutyl moiety of spermidine to a specific lysine residue in the eIF5A precursor protein, i.e. eIF5A(lys). Homospermidine synthase catalyzes an analogous reaction but uses putrescine instead of eIF5A(lys) as substrate yielding the rare polyamine homospermidine as product. Homospermidine is an essential precursor in the biosynthesis of pyrrolizidine alkaloids, an important class of plant defense compounds against herbivores. Sequence comparisons of the two enzymes indicate an evolutionary origin of homospermidine synthase from ubiquitous deoxyhypusine synthase. The two recombinant enzymes from Senecio vernalis were purified, and their properties were compared. Protein-protein binding and kinetic substrate competition studies confirmed that homospermidine synthase, in comparison to deoxyhypusine synthase, lost the ability to bind the eIF5A(lys) to its surface. The two enzymes show the same unique substrate specificities, catalyze the aminobutylation of putrescine with the same specific activities, and exhibit almost identical Michaelis kinetics. In conclusion, homospermidine synthase behaves like a deoxyhypusine synthase that lost its major function (aminobutylation of eIF5A precursor protein) but retained unaltered its side activity (aminobutylation of putrescine). It is suggested as having evolved from deoxyhypusine synthase by gene duplication and being recruited for a new function.
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Affiliation(s)
- Dietrich Ober
- Institut für Pharmazeutische Biologie, Technische Universität Braunschweig, Mendelssohnstrasse 1, D-38106 Braunschweig, Germany
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Kaiser AE, Gottwald AM, Wiersch CS, Maier WA, Seitz HM. Spermidine metabolism in parasitic protozoa--a comparison to the situation in prokaryotes, viruses, plants and fungi. Folia Parasitol (Praha) 2003; 50:3-18. [PMID: 12735718 DOI: 10.14411/fp.2003.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Targeting polyamines of parasitic protozoa in chemotherapy has attracted attention because polyamines might reveal novel drug targets for antiparasite therapies (Müller et al. 2001). The biological function of the triamine spermidine in parasitic protozoa has not been studied in great detail although the results obtained mainly imply three different functions, i.e., cell proliferation, cell differentiation, and biosynthesis of macromolecules. Sequence information from the malaria genome project databases and inhibitor studies provide evidence that the current status of spermidine research has to be extended since enzymes of spermidine metabolism are present in the parasite (Kaiser et al. 2001). Isolation and characterisation of these enzymes, i.e., deoxyhypusine synthase (EC 1.1.1.249) (DHS) and homospermidine synthase (EC 2.5.1.44) (HSS) might lead to valuable new targets in drug therapy. Currently research on spermidine metabolism is based on the deposition of the deoxyhypusine synthase nucleic acid sequence in GenBank while the activity of homospermidine synthase was deduced from inhibitor studies. Spermidine biosynthesis is catalyzed by spermidine synthase (EC 2.5.1.16) which transfers an aminopropyl moiety from decarboxylated S-adenosylmethionine to putrescine. Spermidine is also an important precursor in the biosynthesis of the unusual amino acid hypusine (Wolff et al. 1995) and the uncommon triamine homospermidine in eukaryotes, in particular in pyrrolizidine alkaloid-producing plants (Ober and Hartmann 2000). Hypusine is formed by a two-step enzymatic mechanism starting with the transfer of an aminobutyl moiety from spermidine to the epsilon-amino group of one of the lysine residues in the precursor protein of eukaryotic initiation factor eIF5A by DHS (Lee and Park 2000). The second step of hypusinylation is completed by deoxyhypusine hydroxylase (EC 1.14.9929) (Abbruzzese et al. 1985). Homospermidine formation in eukaryotes parallels deoxyhypusine formation in the way that in an NAD(+)-dependent reaction an aminobutyl moiety is transferred from spermidine. In the case of homospermidine synthase, however the acceptor is putrescine. Thus the triamine homospermidine consists of two symmetric aminobutyl moieties while there is one aminobutyl and one aminopropyl moiety present in spermidine. Here, we review the metabolism of the triamine spermidine with particular focus on the biosynthesis of hypusine and homospermidine in parasitic protozoa, i.e., Plasmodium, Trypanosoma and Leishmania, compared to that in prokaryotes i.e., Escherichia coli, a phytopathogenic virus and pyrrolizidine alkaloid-producing plants (Asteraceae) and fungi.
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Affiliation(s)
- Annette E Kaiser
- Institut für Medizinische Parasitologie, Rheinische-Friedrich-Wilhelms-Universität Bonn, Sigmund-Freud-Strasse 25, 53105 Bonn, Germany.
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Buchanan-Wollaston V, Earl S, Harrison E, Mathas E, Navabpour S, Page T, Pink D. The molecular analysis of leaf senescence--a genomics approach. PLANT BIOTECHNOLOGY JOURNAL 2003; 1:3-22. [PMID: 17147676 DOI: 10.1046/j.1467-7652.2003.00004.x] [Citation(s) in RCA: 377] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Senescence in green plants is a complex and highly regulated process that occurs as part of plant development or can be prematurely induced by stress. In the last decade, the main focus of research has been on the identification of senescence mutants, as well as on genes that show enhanced expression during senescence. Analysis of these is beginning to expand our understanding of the processes by which senescence functions. Recent rapid advances in genomics resources, especially for the model plant species Arabidopsis, are providing scientists with a dazzling array of tools for the identification and functional analysis of the genes and pathways involved in senescence. In this review, we present the current understanding of the mechanisms by which plants control senescence and the processes that are involved.
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