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Fan S, Li Y, Wang Q, Jin M, Yu M, Zhao H, Zhou C, Xu J, Li B, Li X. The role of cis-zeatin in enhancing high-temperature resistance and fucoxanthin biosynthesis in Phaeodactylum tricornutum. Appl Environ Microbiol 2024; 90:e0206823. [PMID: 38786362 PMCID: PMC11218622 DOI: 10.1128/aem.02068-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 04/25/2024] [Indexed: 05/25/2024] Open
Abstract
Phaeodactylum tricornutum a prominent source of industrial fucoxanthin production, faces challenges in its application due to its tolerance to high-temperature environments. This study investigates the physiological responses of P. tricornutum to high-temperature stress and its impact on fucoxanthin content, with a specific focus on the role of cis-zeatin. The results reveal that high-temperature stress inhibits P. tricornutum's growth and photosynthetic activity, leading to a decrease in fucoxanthin content. Transcriptome analysis shows that high temperature suppresses the expression of genes related to photosynthesis (e.g., psbO, psbQ, and OEC) and fucoxanthin biosynthesis (e.g., PYS, PDS1, and PSD2), underscoring the negative effects of high temperature on P. tricornutum. Interestingly, genes associated with cis-zeatin biosynthesis and cytokinesis signaling pathways exhibited increased expression under high-temperature conditions, indicating a potential role of cis-zeatin signaling in response to elevated temperatures. Content measurements confirm that high temperature enhances cis-zeatin content. Furthermore, the exogenous addition of cytokinesis mimetics or inhibitors significantly affected P. tricornutum's high-temperature resistance. Overexpression of the cis-zeatin biosynthetic enzyme gene tRNA DMATase enhanced P. tricornutum's resistance to high-temperature stress, while genetic knockout of tRNA DMATase reduced its resistance to high temperatures. Therefore, this research not only uncovers a novel mechanism for high-temperature resistance in P. tricornutum but also offers a possible alga species that can withstand high temperatures for the industrial production of fucoxanthin, offering valuable insights for practical utilization.IMPORTANCEThis study delves into Phaeodactylum tricornutum's response to high-temperature stress, specifically focusing on cis-zeatin. We uncover inhibited growth, reduced fucoxanthin, and significant cis-zeatin-related gene expression under high temperatures, highlighting potential signaling mechanisms. Crucially, genetic engineering and exogenous addition experiments confirm that the change in cis-zeatin levels could influence P. tricornutum's resistance to high-temperature stress. This breakthrough deepens our understanding of microalgae adaptation to high temperatures and offers an innovative angle for industrial fucoxanthin production. This research is a pivotal step toward developing heat-resistant microalgae for industrial use.
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Affiliation(s)
- Sizhe Fan
- School of Marine Sciences, Ningbo University, Ningbo, China
| | - Yixuan Li
- College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, China
| | - Qi Wang
- College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, China
| | - Mengjie Jin
- College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, China
| | - Mange Yu
- School of Marine Sciences, Ningbo University, Ningbo, China
| | - Hejing Zhao
- School of Marine Sciences, Ningbo University, Ningbo, China
| | - Chengxu Zhou
- College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, China
| | - Jilin Xu
- School of Marine Sciences, Ningbo University, Ningbo, China
| | - Bing Li
- School of Civil & Environmental Engineering and Geography Science, Ningbo University, Ningbo, China, Ningbo, China
| | - Xiaohui Li
- College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, China
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Zhai N, Sun B, Wu S, Zhou F, Jiao Y, Xu L. Cytokinin facilitates the patterning of the adventitious root apical meristem from leaf cuttings. MOLECULAR HORTICULTURE 2024; 4:11. [PMID: 38528592 DOI: 10.1186/s43897-024-00091-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Accepted: 03/05/2024] [Indexed: 03/27/2024]
Affiliation(s)
- Ning Zhai
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai, 200032, China
- Key Laboratory of Plant Carbon Capture, CAS, Shanghai, 200032, China
| | - Beibei Sun
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai, 200032, China
- Key Laboratory of Plant Carbon Capture, CAS, Shanghai, 200032, China
- College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Shasha Wu
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai, 200032, China
- Key Laboratory of Plant Carbon Capture, CAS, Shanghai, 200032, China
- College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Feng Zhou
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai, 200032, China
- Key Laboratory of Plant Carbon Capture, CAS, Shanghai, 200032, China
| | - Yuling Jiao
- School of Life Sciences and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Lin Xu
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai, 200032, China.
- Key Laboratory of Plant Carbon Capture, CAS, Shanghai, 200032, China.
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Yi M, Yang H, Yang S, Wang J. Overexpression of SHORT-ROOT2 transcription factor enhances the outgrowth of mature axillary buds in poplar trees. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:2469-2486. [PMID: 35107566 DOI: 10.1093/jxb/erac040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Accepted: 02/01/2022] [Indexed: 06/14/2023]
Abstract
SHORT-ROOT (SHR) transcription factors play important roles in asymmetric cell division and radial patterning of Arabidopsis roots. In hybrid poplar (P. tremula × P. alba clone INRA 717-1B4), PtaSHR2 was preferentially expressed in axillary buds (AXBs) and transcriptionally up-regulated during AXB maturation and activation. Overexpression of SHR2 (PtSHR2OE) induced an enhanced outgrowth of AXBs below the bud maturation point, with a simultaneous transition of an active shoot apex into an arrested terminal bud. The larger and more mature AXBs of PtSHR2OE trees revealed altered expression of genes involved in axillary meristem initiation and bud activation, as well as a higher ratio of cytokinin to auxin. To elucidate the underlying mechanism of PtSHR2OE-induced high branching, subsequent molecular and biochemical studies showed that compared with wild-type trees, decapitation induced a quicker bud outburst in PtSHR2OE trees, which could be fully inhibited by exogenous application of auxin or cytokinin biosynthesis inhibitor, but not by N-1-naphthylphthalamic acid. Our results indicated that overexpression of PtSHR2B disturbed the internal hormonal balance in AXBs by interfering with the basipetal transport of auxin, rather than causing auxin biosynthesis deficiency or auxin insensitivity, thereby releasing mature AXBs from apical dominance and promoting their outgrowth.
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Affiliation(s)
- Minglei Yi
- School of Environmental Science and Engineering, Tianjin University, Tianjin, China
| | - Heyu Yang
- School of Environmental Science and Engineering, Tianjin University, Tianjin, China
| | - Shaohui Yang
- School of Environmental Science and Engineering, Tianjin University, Tianjin, China
| | - Jiehua Wang
- School of Environmental Science and Engineering, Tianjin University, Tianjin, China
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Cao H, Zhang X, Ruan Y, Zhang L, Cui Z, Li X, Jia B. miRNA expression profiling and zeatin dynamic changes in a new model system of in vivo indirect regeneration of tomato. PLoS One 2020; 15:e0237690. [PMID: 33332392 PMCID: PMC7745965 DOI: 10.1371/journal.pone.0237690] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 11/27/2020] [Indexed: 01/15/2023] Open
Abstract
Callus formation and adventitious shoot differentiation could be observed on the cut surface of completely decapitated tomato plants. We propose that this process can be used as a model system to investigate the mechanisms that regulate indirect regeneration of higher plants without the addition of exogenous hormones. This study analyzed the patterns of trans-zeatin and miRNA expression during in vivo regeneration of tomato. Analysis of trans-zeatin revealed that the hormone cytokinin played an important role in in vivo regeneration of tomato. Among 183 miRNAs and 1168 predicted target genes sequences identified, 93 miRNAs and 505 potential targets were selected based on differential expression levels for further characterization. Expression patterns of six miRNAs, including sly-miR166, sly-miR167, sly-miR396, sly-miR397, novel 156, and novel 128, were further validated by qRT-PCR. We speculate that sly-miR156, sly-miR160, sly-miR166, and sly-miR397 play major roles in callus formation of tomato during in vivo regeneration by regulating cytokinin, IAA, and laccase levels. Overall, our microRNA sequence and target analyses of callus formation during in vivo regeneration of tomato provide novel insights into the regulation of regeneration in higher plants.
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Affiliation(s)
- Huiying Cao
- College of Biological Science and Technology, Liaoning Province Research Center of Plant Genetic Engineering Technology, Shenyang Key Laboratory of Maize Genomic Selection Breeding, Shenyang Agricultural University, Shenyang, China
| | - Xinyue Zhang
- College of Biological Science and Technology, Liaoning Province Research Center of Plant Genetic Engineering Technology, Shenyang Key Laboratory of Maize Genomic Selection Breeding, Shenyang Agricultural University, Shenyang, China
| | - Yanye Ruan
- College of Biological Science and Technology, Liaoning Province Research Center of Plant Genetic Engineering Technology, Shenyang Key Laboratory of Maize Genomic Selection Breeding, Shenyang Agricultural University, Shenyang, China
- * E-mail: (YR); (LZ)
| | - Lijun Zhang
- College of Biological Science and Technology, Liaoning Province Research Center of Plant Genetic Engineering Technology, Shenyang Key Laboratory of Maize Genomic Selection Breeding, Shenyang Agricultural University, Shenyang, China
- * E-mail: (YR); (LZ)
| | - Zhenhai Cui
- College of Biological Science and Technology, Liaoning Province Research Center of Plant Genetic Engineering Technology, Shenyang Key Laboratory of Maize Genomic Selection Breeding, Shenyang Agricultural University, Shenyang, China
| | - Xuxiao Li
- College of Biological Science and Technology, Liaoning Province Research Center of Plant Genetic Engineering Technology, Shenyang Key Laboratory of Maize Genomic Selection Breeding, Shenyang Agricultural University, Shenyang, China
| | - Bing Jia
- College of Biological Science and Technology, Liaoning Province Research Center of Plant Genetic Engineering Technology, Shenyang Key Laboratory of Maize Genomic Selection Breeding, Shenyang Agricultural University, Shenyang, China
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Zheng T, Dong T, Haider MS, Jin H, Jia H, Fang J. Brassinosteroid Regulates 3-Hydroxy-3-methylglutaryl CoA Reductase to Promote Grape Fruit Development. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:11987-11996. [PMID: 33059448 DOI: 10.1021/acs.jafc.0c04466] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Brassinosteroids (BRs) are known to regulate plant growth and development. However, only little is known about their mechanism in the regulation of berry development in grapes. This study demonstrates that BR treatment enhances the accumulation of fruit sugar components, reduces the content of organic acids (e.g., tartaric acid), promotes coloration, and increases the anthocyanin content in grape berries at the onset of the veraison, half veraison, and full veraison stages at the rate of 0.0998, 0.0560, and 0.0281 mg·g-1, respectively. In addition, BR treatment was also found to accelerate the biosynthesis of terpenoid aroma components, such as α-pinene, d-limonene, and γ-terpinene, which influence the aromatic composition of grapes. BRs can negatively regulate the expression of VvHMGR, a key gene involved in the mevalonate (MVA) pathway, and reduce the activity of 3-hydroxy-3-methylglutaryl CoA reductase (HMGR). Inhibiting the expression of HMGR promoted the accumulation of anthocyanins and fruit coloration. Meanwhile, after the inhibition, the contents of auxin indole-3-acetic acid (IAA), abscisic acid (ABA), and brassinosteroid (BR) increased, while gibberellin (GA3) and zeatin riboside (ZR) decreased, and its aromatic composition also changed. Therefore, it may be concluded that BRs inhibited HMGR activity and cooperated with VvHMGR to regulate the formation of color, aroma, and other quality characteristics in fruits.
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Affiliation(s)
- Ting Zheng
- College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Tianyu Dong
- College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Muhammad S Haider
- College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Huanchun Jin
- College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Haifeng Jia
- College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
- China Wine Industry Technology Institute, Yinchuan 750000, China
| | - Jinggui Fang
- College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
- China Wine Industry Technology Institute, Yinchuan 750000, China
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6
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He G, Yang P, Tang Y, Cao Y, Qi X, Xu L, Ming J. Mechanism of exogenous cytokinins inducing bulbil formation in Lilium lancifolium in vitro. PLANT CELL REPORTS 2020; 39:861-872. [PMID: 32270280 DOI: 10.1007/s00299-020-02535-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 03/26/2020] [Indexed: 06/11/2023]
Abstract
The cytokinin pathway promotes the initiation of bulbil formation, and iPA may an important type of cytokinin during bulbil formation in Lilium lancifolium. Bulbils are important vegetative reproductive organs in triploid Lilium lancifolium. We previously showed that cytokinins are involved in bulbil formation, but how cytokinins participate in bulbil formation is not clear. In this study, bulbil formation was divided into three stages on the basis of anatomical and histological observations: the bulbil initiation stage, bulbil primordium-formation stage and bulbil structure-formation stage. The results indicated that iPA was the most critical cytokinin during the bulbil initiation. qRT-PCR revealed that increased iPA content during bulbil initiation was mainly due to increased expression of cytokinin synthesis genes (IPT1/5) and cytokinin activation genes (LOG1/3/5/7) and significantly decreased expression of the cytokinin degradation gene CKX4. Exogenous 6-BA and lovastatin affected the cytokinin pathway and promoted or inhibited bulbil initiation by increasing or decreasing the content of endogenous iPA, respectively. In summary, we demonstrate that cytokinins positively regulate bulbil formation and provide preliminary insight into the regulatory mechanisms by which the cytokinin pathway promotes bulbil initiation.
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Affiliation(s)
- Guoren He
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Panpan Yang
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Yuchao Tang
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Yuwei Cao
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Xianyu Qi
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Leifeng Xu
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Jun Ming
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
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Zou X, Shao J, Wang Q, Chen P, Zhu Y, Yin C. Supraoptimal Cytokinin Content Inhibits Rice Seminal Root Growth by Reducing Root Meristem Size and Cell Length via Increased Ethylene Content. Int J Mol Sci 2018; 19:ijms19124051. [PMID: 30558185 PMCID: PMC6321243 DOI: 10.3390/ijms19124051] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 11/30/2018] [Accepted: 12/12/2018] [Indexed: 02/06/2023] Open
Abstract
Cytokinins (CKs), a class of phytohormone, regulate root growth in a dose-dependent manner. A certain threshold content of CK is required for rapid root growth, but supraoptimal CK content inhibits root growth, and the mechanism of this inhibition remains unclear in rice. In this study, treatments of lovastatin (an inhibitor of CK biosynthesis) and kinetin (KT; a synthetic CK) were found to inhibit rice seminal root growth in a dose-dependent manner, suggesting that endogenous CK content is optimal for rapid growth of the seminal root in rice. KT treatment strongly increased ethylene level by upregulating the transcription of ethylene biosynthesis genes. Ethylene produced in response to exogenous KT inhibited rice seminal root growth by reducing meristem size via upregulation of OsIAA3 transcription and reduced cell length by downregulating transcription of cell elongation-related genes. Moreover, the effects of KT treatment on rice seminal root growth, root meristem size and cell length were rescued by treatment with aminoethoxyvinylglycine (an inhibitor of ethylene biosynthesis), which restored ethylene level and transcription levels of OsIAA3 and cell elongation-related genes. Supraoptimal CK content increases ethylene level by promoting ethylene biosynthesis, which in turn inhibits rice seminal root growth by reducing root meristem size and cell length.
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Affiliation(s)
- Xiao Zou
- MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430062, China.
| | - Junwei Shao
- MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430062, China.
| | - Qi Wang
- MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430062, China.
| | - Peisai Chen
- MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430062, China.
| | - Yanchun Zhu
- MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430062, China.
| | - Changxi Yin
- MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430062, China.
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Luo Y, Tang Y, Zhang X, Li W, Chang Y, Pang D, Xu X, Li Y, Wang Z. Interactions between cytokinin and nitrogen contribute to grain mass in wheat cultivars by regulating the flag leaf senescence process. ACTA ACUST UNITED AC 2018. [DOI: 10.1016/j.cj.2018.05.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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9
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Binder BM, Kim HJ, Mathews DE, Hutchison CE, Kieber JJ, Schaller GE. A role for two-component signaling elements in the Arabidopsis growth recovery response to ethylene. PLANT DIRECT 2018; 2:e00058. [PMID: 31245724 PMCID: PMC6508545 DOI: 10.1002/pld3.58] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 04/16/2018] [Accepted: 04/17/2018] [Indexed: 05/29/2023]
Abstract
Previous studies indicate that the ability of Arabidopsis seedlings to recover normal growth following an ethylene treatment involves histidine kinase activity of the ethylene receptors. As histidine kinases can function as inputs for a two-component signaling system, we examined loss-of-function mutants involving two-component signaling elements. We find that mutants of phosphotransfer proteins and type-B response regulators exhibit a defect in their ethylene growth recovery response similar to that found with the loss-of-function ethylene receptor mutant etr1-7. The ability of two-component signaling elements to regulate the growth recovery response to ethylene functions independently from their well-characterized role in cytokinin signaling, based on the analysis of cytokinin receptor mutants as well as following chemical inhibition of cytokinin biosynthesis. Histidine kinase activity of the receptor ETR1 also facilitates growth recovery in the ethylene hypersensitive response, which is characterized by a transient decrease in growth rate when seedlings are treated continuously with a low dose of ethylene; however, this response was found to operate independently of the type-B response regulators. These results indicate that histidine kinase activity of the ethylene receptor ETR1 performs two independent functions: (a) regulating the growth recovery to ethylene through a two-component signaling system involving phosphotransfer proteins and type-B response regulators and (b) regulating the hypersensitive response to ethylene in a type-B response regulator independent manner.
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Affiliation(s)
- Brad M. Binder
- Department of Biochemistry and Cellular & Molecular BiologyUniversity of TennesseeKnoxvilleTennessee
| | - Hyo Jung Kim
- Department of Biological SciencesDartmouth CollegeHanoverNew Hampshire
- Center for Plant Aging ResearchInstitute for Basic Science (IBS)DaeguKorea
| | - Dennis E. Mathews
- Department of Molecular, Cellular, and Biomedical SciencesUniversity of New HampshireDurhamNew Hampshire
| | - Claire E. Hutchison
- Department of BiologyUniversity of North CarolinaChapel HillNorth Carolina
- Present address:
William Harvey Research InstituteQueen Mary University of LondonCharterhouse SquareLondonEC1M 6BQUK
| | - Joseph J. Kieber
- Department of BiologyUniversity of North CarolinaChapel HillNorth Carolina
| | - G. Eric Schaller
- Department of Biological SciencesDartmouth CollegeHanoverNew Hampshire
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Bhargavi SD, Praveen VK, Anil Kumar M, Savitha J. Comparative Study on Whole Genome Sequences of Aspergillus terreus (Soil Fungus) and Diaporthe ampelina (Endophytic Fungus) with Reference to Lovastatin Production. Curr Microbiol 2017; 75:84-91. [PMID: 28879444 DOI: 10.1007/s00284-017-1353-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 08/31/2017] [Indexed: 12/21/2022]
Abstract
Lovastatin is a competitive inhibitor of the enzyme hydroxymethyl glutaryl coenzyme A reductase (HMGR) in cholesterol biosynthetic pathway and hence used in the treatment of hyperlipidemia. In a previous study, we report a tropical soil isolate, Aspergillus terreus (KM017963), which produces ample amount of lovastatin than its counterpart that are endophytic in origin. Bioinformatic analysis of whole genome sequence of A. terreus (AH007774.1), a soil isolate revealed the presence of gene cluster (AF141924.1 & AF141925.1) responsible for lovastatin production, whereas endophytic fungi including a strain of A. terreus showed no homology with the lovastatin gene cluster. The molecular study was also carried out targeting PCR amplification of the two important genes, lovE (a regulatory gene) and lovF (transcriptional regulatory factor) in genomic and c-DNA of soil and endophytic fungi. Expression of the two genes was successful in A. terreus (KM017963), whereas the same was not achieved in endophytic fungi. To further validate our above findings, in the present study, the whole genome sequencing of A. terreus and a selected endophytic fungus, Diaporthe ampelina (Phomopsis) was performed. Lovastatin gene cluster, when aligned on the consensus sequence of both genomes, the entire lovastatin gene cluster was detected in a single scaffold (1.16) of A.terreus genome. On the contrary, there was a complete absence of lovastatin gene cluster in the genome of D. ampelina (an endophyte). The probable reasons for the absence of lovastatin gene cluster in endophytic fungi are discussed.
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Affiliation(s)
- S D Bhargavi
- Department of Microbiology and Biotechnology, Bangalore University, JB Campus, Bangalore, 560056, India
| | - V K Praveen
- Department of Microbiology and Biotechnology, Bangalore University, JB Campus, Bangalore, 560056, India
| | - M Anil Kumar
- Department of Microbiology and Biotechnology, Bangalore University, JB Campus, Bangalore, 560056, India
| | - J Savitha
- Department of Microbiology and Biotechnology, Bangalore University, JB Campus, Bangalore, 560056, India.
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Manzano D, Andrade P, Caudepón D, Altabella T, Arró M, Ferrer A. Suppressing Farnesyl Diphosphate Synthase Alters Chloroplast Development and Triggers Sterol-Dependent Induction of Jasmonate- and Fe-Related Responses. PLANT PHYSIOLOGY 2016; 172:93-117. [PMID: 27382138 PMCID: PMC5074618 DOI: 10.1104/pp.16.00431] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 06/30/2016] [Indexed: 05/22/2023]
Abstract
Farnesyl diphosphate synthase (FPS) catalyzes the synthesis of farnesyl diphosphate from isopentenyl diphosphate and dimethylallyl diphosphate. Arabidopsis (Arabidopsis thaliana) contains two genes (FPS1 and FPS2) encoding FPS. Single fps1 and fps2 knockout mutants are phenotypically indistinguishable from wild-type plants, while fps1/fps2 double mutants are embryo lethal. To assess the effect of FPS down-regulation at postembryonic developmental stages, we generated Arabidopsis conditional knockdown mutants expressing artificial microRNAs devised to simultaneously silence both FPS genes. Induction of silencing from germination rapidly caused chlorosis and a strong developmental phenotype that led to seedling lethality. However, silencing of FPS after seed germination resulted in a slight developmental delay only, although leaves and cotyledons continued to show chlorosis and altered chloroplasts. Metabolomic analyses also revealed drastic changes in the profile of sterols, ubiquinones, and plastidial isoprenoids. RNA sequencing and reverse transcription-quantitative polymerase chain reaction transcriptomic analysis showed that a reduction in FPS activity levels triggers the misregulation of genes involved in biotic and abiotic stress responses, the most prominent one being the rapid induction of a set of genes related to the jasmonic acid pathway. Down-regulation of FPS also triggered an iron-deficiency transcriptional response that is consistent with the iron-deficient phenotype observed in FPS-silenced plants. The specific inhibition of the sterol biosynthesis pathway by chemical and genetic blockage mimicked these transcriptional responses, indicating that sterol depletion is the primary cause of the observed alterations. Our results highlight the importance of sterol homeostasis for normal chloroplast development and function and reveal important clues about how isoprenoid and sterol metabolism is integrated within plant physiology and development.
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Affiliation(s)
- David Manzano
- Plant Metabolism and Metabolic Engineering Program, Centre for Research in Agricultural Genomics, CSIC-IRTA-UAB-UB, Campus UAB, Bellaterra (Cerdanyola del Vallès), Barcelona, Spain (D.M., P.A., D.C., T.A., M.A., A.F.); andDepartment of Biochemistry and Molecular Biology (D.M., P.A., D.C., M.A., A.F.) and Plant Physiology Unit (T.A.), Faculty of Pharmacy, University of Barcelona, Barcelona, Spain
| | - Paola Andrade
- Plant Metabolism and Metabolic Engineering Program, Centre for Research in Agricultural Genomics, CSIC-IRTA-UAB-UB, Campus UAB, Bellaterra (Cerdanyola del Vallès), Barcelona, Spain (D.M., P.A., D.C., T.A., M.A., A.F.); andDepartment of Biochemistry and Molecular Biology (D.M., P.A., D.C., M.A., A.F.) and Plant Physiology Unit (T.A.), Faculty of Pharmacy, University of Barcelona, Barcelona, Spain
| | - Daniel Caudepón
- Plant Metabolism and Metabolic Engineering Program, Centre for Research in Agricultural Genomics, CSIC-IRTA-UAB-UB, Campus UAB, Bellaterra (Cerdanyola del Vallès), Barcelona, Spain (D.M., P.A., D.C., T.A., M.A., A.F.); andDepartment of Biochemistry and Molecular Biology (D.M., P.A., D.C., M.A., A.F.) and Plant Physiology Unit (T.A.), Faculty of Pharmacy, University of Barcelona, Barcelona, Spain
| | - Teresa Altabella
- Plant Metabolism and Metabolic Engineering Program, Centre for Research in Agricultural Genomics, CSIC-IRTA-UAB-UB, Campus UAB, Bellaterra (Cerdanyola del Vallès), Barcelona, Spain (D.M., P.A., D.C., T.A., M.A., A.F.); andDepartment of Biochemistry and Molecular Biology (D.M., P.A., D.C., M.A., A.F.) and Plant Physiology Unit (T.A.), Faculty of Pharmacy, University of Barcelona, Barcelona, Spain
| | - Montserrat Arró
- Plant Metabolism and Metabolic Engineering Program, Centre for Research in Agricultural Genomics, CSIC-IRTA-UAB-UB, Campus UAB, Bellaterra (Cerdanyola del Vallès), Barcelona, Spain (D.M., P.A., D.C., T.A., M.A., A.F.); andDepartment of Biochemistry and Molecular Biology (D.M., P.A., D.C., M.A., A.F.) and Plant Physiology Unit (T.A.), Faculty of Pharmacy, University of Barcelona, Barcelona, Spain
| | - Albert Ferrer
- Plant Metabolism and Metabolic Engineering Program, Centre for Research in Agricultural Genomics, CSIC-IRTA-UAB-UB, Campus UAB, Bellaterra (Cerdanyola del Vallès), Barcelona, Spain (D.M., P.A., D.C., T.A., M.A., A.F.); andDepartment of Biochemistry and Molecular Biology (D.M., P.A., D.C., M.A., A.F.) and Plant Physiology Unit (T.A.), Faculty of Pharmacy, University of Barcelona, Barcelona, Spain
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12
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Roman H, Girault T, Barbier F, Péron T, Brouard N, Pěnčík A, Novák O, Vian A, Sakr S, Lothier J, Le Gourrierec J, Leduc N. Cytokinins Are Initial Targets of Light in the Control of Bud Outgrowth. PLANT PHYSIOLOGY 2016; 172:489-509. [PMID: 27462085 PMCID: PMC5074613 DOI: 10.1104/pp.16.00530] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 07/24/2016] [Indexed: 05/18/2023]
Abstract
Bud outgrowth is controlled by environmental and endogenous factors. Through the use of the photosynthesis inhibitor norflurazon and of masking experiments, evidence is given here that light acts mainly as a morphogenic signal in the triggering of bud outgrowth and that initial steps in the light signaling pathway involve cytokinins (CKs). Indeed, in rose (Rosa hybrida), inhibition of bud outgrowth by darkness is suppressed solely by the application of CKs. In contrast, application of sugars has a limited effect. Exposure of plants to white light (WL) induces a rapid (after 3-6 h of WL exposure) up-regulation of CK synthesis (RhIPT3 and RhIPT5), of CK activation (RhLOG8), and of CK putative transporter RhPUP5 genes and to the repression of the CK degradation RhCKX1 gene in the node. This leads to the accumulation of CKs in the node within 6 h and in the bud at 24 h and to the triggering of bud outgrowth. Molecular analysis of genes involved in major mechanisms of bud outgrowth (strigolactone signaling [RwMAX2], metabolism and transport of auxin [RhPIN1, RhYUC1, and RhTAR1], regulation of sugar sink strength [RhVI, RhSUSY, RhSUC2, and RhSWEET10], and cell division and expansion [RhEXP and RhPCNA]) reveal that, when supplied in darkness, CKs up-regulate their expression as rapidly and as intensely as WL Additionally, up-regulation of CKs by WL promotes xylem flux toward the bud, as evidenced by Methylene Blue accumulation in the bud after CK treatment in the dark. Altogether, these results suggest that CKs are initial components of the light signaling pathway that controls the initiation of bud outgrowth.
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Affiliation(s)
- Hanaé Roman
- IRHS (Research Institute on Horticulture and Seeds), Université d'Angers, Agrocampus-Ouest, Institut National de la Recherche Agronomique, SFR 4207 QUASAV, 49070 Beaucouzé, France (H.R., T.G., F.B., T.P., N.B., A.V., S.S., J.L., J.L.G., N.L.); andLaboratory of Growth Regulators and Department of Chemical Biology and Genetics, Palacký University and Institute of Experimental Botany, Academy of Sciences of the Czech Republic, CZ-78371 Olomouc, Czech Republic (A.P., O.N.)
| | - Tiffanie Girault
- IRHS (Research Institute on Horticulture and Seeds), Université d'Angers, Agrocampus-Ouest, Institut National de la Recherche Agronomique, SFR 4207 QUASAV, 49070 Beaucouzé, France (H.R., T.G., F.B., T.P., N.B., A.V., S.S., J.L., J.L.G., N.L.); andLaboratory of Growth Regulators and Department of Chemical Biology and Genetics, Palacký University and Institute of Experimental Botany, Academy of Sciences of the Czech Republic, CZ-78371 Olomouc, Czech Republic (A.P., O.N.)
| | - François Barbier
- IRHS (Research Institute on Horticulture and Seeds), Université d'Angers, Agrocampus-Ouest, Institut National de la Recherche Agronomique, SFR 4207 QUASAV, 49070 Beaucouzé, France (H.R., T.G., F.B., T.P., N.B., A.V., S.S., J.L., J.L.G., N.L.); andLaboratory of Growth Regulators and Department of Chemical Biology and Genetics, Palacký University and Institute of Experimental Botany, Academy of Sciences of the Czech Republic, CZ-78371 Olomouc, Czech Republic (A.P., O.N.)
| | - Thomas Péron
- IRHS (Research Institute on Horticulture and Seeds), Université d'Angers, Agrocampus-Ouest, Institut National de la Recherche Agronomique, SFR 4207 QUASAV, 49070 Beaucouzé, France (H.R., T.G., F.B., T.P., N.B., A.V., S.S., J.L., J.L.G., N.L.); andLaboratory of Growth Regulators and Department of Chemical Biology and Genetics, Palacký University and Institute of Experimental Botany, Academy of Sciences of the Czech Republic, CZ-78371 Olomouc, Czech Republic (A.P., O.N.)
| | - Nathalie Brouard
- IRHS (Research Institute on Horticulture and Seeds), Université d'Angers, Agrocampus-Ouest, Institut National de la Recherche Agronomique, SFR 4207 QUASAV, 49070 Beaucouzé, France (H.R., T.G., F.B., T.P., N.B., A.V., S.S., J.L., J.L.G., N.L.); andLaboratory of Growth Regulators and Department of Chemical Biology and Genetics, Palacký University and Institute of Experimental Botany, Academy of Sciences of the Czech Republic, CZ-78371 Olomouc, Czech Republic (A.P., O.N.)
| | - Aleš Pěnčík
- IRHS (Research Institute on Horticulture and Seeds), Université d'Angers, Agrocampus-Ouest, Institut National de la Recherche Agronomique, SFR 4207 QUASAV, 49070 Beaucouzé, France (H.R., T.G., F.B., T.P., N.B., A.V., S.S., J.L., J.L.G., N.L.); andLaboratory of Growth Regulators and Department of Chemical Biology and Genetics, Palacký University and Institute of Experimental Botany, Academy of Sciences of the Czech Republic, CZ-78371 Olomouc, Czech Republic (A.P., O.N.)
| | - Ondřej Novák
- IRHS (Research Institute on Horticulture and Seeds), Université d'Angers, Agrocampus-Ouest, Institut National de la Recherche Agronomique, SFR 4207 QUASAV, 49070 Beaucouzé, France (H.R., T.G., F.B., T.P., N.B., A.V., S.S., J.L., J.L.G., N.L.); andLaboratory of Growth Regulators and Department of Chemical Biology and Genetics, Palacký University and Institute of Experimental Botany, Academy of Sciences of the Czech Republic, CZ-78371 Olomouc, Czech Republic (A.P., O.N.)
| | - Alain Vian
- IRHS (Research Institute on Horticulture and Seeds), Université d'Angers, Agrocampus-Ouest, Institut National de la Recherche Agronomique, SFR 4207 QUASAV, 49070 Beaucouzé, France (H.R., T.G., F.B., T.P., N.B., A.V., S.S., J.L., J.L.G., N.L.); andLaboratory of Growth Regulators and Department of Chemical Biology and Genetics, Palacký University and Institute of Experimental Botany, Academy of Sciences of the Czech Republic, CZ-78371 Olomouc, Czech Republic (A.P., O.N.)
| | - Soulaiman Sakr
- IRHS (Research Institute on Horticulture and Seeds), Université d'Angers, Agrocampus-Ouest, Institut National de la Recherche Agronomique, SFR 4207 QUASAV, 49070 Beaucouzé, France (H.R., T.G., F.B., T.P., N.B., A.V., S.S., J.L., J.L.G., N.L.); andLaboratory of Growth Regulators and Department of Chemical Biology and Genetics, Palacký University and Institute of Experimental Botany, Academy of Sciences of the Czech Republic, CZ-78371 Olomouc, Czech Republic (A.P., O.N.)
| | - Jérémy Lothier
- IRHS (Research Institute on Horticulture and Seeds), Université d'Angers, Agrocampus-Ouest, Institut National de la Recherche Agronomique, SFR 4207 QUASAV, 49070 Beaucouzé, France (H.R., T.G., F.B., T.P., N.B., A.V., S.S., J.L., J.L.G., N.L.); andLaboratory of Growth Regulators and Department of Chemical Biology and Genetics, Palacký University and Institute of Experimental Botany, Academy of Sciences of the Czech Republic, CZ-78371 Olomouc, Czech Republic (A.P., O.N.)
| | - José Le Gourrierec
- IRHS (Research Institute on Horticulture and Seeds), Université d'Angers, Agrocampus-Ouest, Institut National de la Recherche Agronomique, SFR 4207 QUASAV, 49070 Beaucouzé, France (H.R., T.G., F.B., T.P., N.B., A.V., S.S., J.L., J.L.G., N.L.); andLaboratory of Growth Regulators and Department of Chemical Biology and Genetics, Palacký University and Institute of Experimental Botany, Academy of Sciences of the Czech Republic, CZ-78371 Olomouc, Czech Republic (A.P., O.N.)
| | - Nathalie Leduc
- IRHS (Research Institute on Horticulture and Seeds), Université d'Angers, Agrocampus-Ouest, Institut National de la Recherche Agronomique, SFR 4207 QUASAV, 49070 Beaucouzé, France (H.R., T.G., F.B., T.P., N.B., A.V., S.S., J.L., J.L.G., N.L.); andLaboratory of Growth Regulators and Department of Chemical Biology and Genetics, Palacký University and Institute of Experimental Botany, Academy of Sciences of the Czech Republic, CZ-78371 Olomouc, Czech Republic (A.P., O.N.)
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Keim V, Manzano D, Fernández FJ, Closa M, Andrade P, Caudepón D, Bortolotti C, Vega MC, Arró M, Ferrer A. Characterization of Arabidopsis FPS isozymes and FPS gene expression analysis provide insight into the biosynthesis of isoprenoid precursors in seeds. PLoS One 2012; 7:e49109. [PMID: 23145086 PMCID: PMC3492304 DOI: 10.1371/journal.pone.0049109] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Accepted: 10/07/2012] [Indexed: 11/19/2022] Open
Abstract
Arabidopsis thaliana contains two genes encoding farnesyl diphosphate (FPP) synthase (FPS), the prenyl diphoshate synthase that catalyzes the synthesis of FPP from isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP). In this study, we provide evidence that the two Arabidopsis short FPS isozymes FPS1S and FPS2 localize to the cytosol. Both enzymes were expressed in E. coli, purified and biochemically characterized. Despite FPS1S and FPS2 share more than 90% amino acid sequence identity, FPS2 was found to be more efficient as a catalyst, more sensitive to the inhibitory effect of NaCl, and more resistant to thermal inactivation than FPS1S. Homology modelling for FPS1S and FPS2 and analysis of the amino acid differences between the two enzymes revealed an increase in surface polarity and a greater capacity to form surface salt bridges of FPS2 compared to FPS1S. These factors most likely account for the enhanced thermostability of FPS2. Expression analysis of FPS::GUS genes in seeds showed that FPS1 and FPS2 display complementary patterns of expression particularly at late stages of seed development, which suggests that Arabidopsis seeds have two spatially segregated sources of FPP. Functional complementation studies of the Arabidopsis fps2 knockout mutant seed phenotypes demonstrated that under normal conditions FPS1S and FPS2 are functionally interchangeable. A putative role for FPS2 in maintaining seed germination capacity under adverse environmental conditions is discussed.
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Affiliation(s)
- Verónica Keim
- Department of Molecular Genetics, Centre for Research in Agricultural Genomics (CRAG) (CSIC-IRTA-UAB-UB), Campus UAB, Bellaterra (Cerdanyola del Vallès), Barcelona, Spain
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Barcelona, Barcelona, Spain
| | - David Manzano
- Department of Molecular Genetics, Centre for Research in Agricultural Genomics (CRAG) (CSIC-IRTA-UAB-UB), Campus UAB, Bellaterra (Cerdanyola del Vallès), Barcelona, Spain
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Barcelona, Barcelona, Spain
| | - Francisco J. Fernández
- Department of Structural and Quantitative Biology, Centre for Biological Research (CIB-CSIC), Madrid, Spain
| | - Marta Closa
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Barcelona, Barcelona, Spain
| | - Paola Andrade
- Department of Molecular Genetics, Centre for Research in Agricultural Genomics (CRAG) (CSIC-IRTA-UAB-UB), Campus UAB, Bellaterra (Cerdanyola del Vallès), Barcelona, Spain
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Barcelona, Barcelona, Spain
| | - Daniel Caudepón
- Department of Molecular Genetics, Centre for Research in Agricultural Genomics (CRAG) (CSIC-IRTA-UAB-UB), Campus UAB, Bellaterra (Cerdanyola del Vallès), Barcelona, Spain
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Barcelona, Barcelona, Spain
| | - Cristina Bortolotti
- Department of Molecular Genetics, Centre for Research in Agricultural Genomics (CRAG) (CSIC-IRTA-UAB-UB), Campus UAB, Bellaterra (Cerdanyola del Vallès), Barcelona, Spain
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Barcelona, Barcelona, Spain
| | - M. Cristina Vega
- Department of Structural and Quantitative Biology, Centre for Biological Research (CIB-CSIC), Madrid, Spain
| | - Montserrat Arró
- Department of Molecular Genetics, Centre for Research in Agricultural Genomics (CRAG) (CSIC-IRTA-UAB-UB), Campus UAB, Bellaterra (Cerdanyola del Vallès), Barcelona, Spain
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Barcelona, Barcelona, Spain
| | - Albert Ferrer
- Department of Molecular Genetics, Centre for Research in Agricultural Genomics (CRAG) (CSIC-IRTA-UAB-UB), Campus UAB, Bellaterra (Cerdanyola del Vallès), Barcelona, Spain
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, University of Barcelona, Barcelona, Spain
- * E-mail:
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14
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Hemmerlin A, Harwood JL, Bach TJ. A raison d'être for two distinct pathways in the early steps of plant isoprenoid biosynthesis? Prog Lipid Res 2011; 51:95-148. [PMID: 22197147 DOI: 10.1016/j.plipres.2011.12.001] [Citation(s) in RCA: 208] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Revised: 11/28/2011] [Accepted: 12/05/2011] [Indexed: 12/12/2022]
Abstract
When compared to other organisms, plants are atypical with respect to isoprenoid biosynthesis: they utilize two distinct and separately compartmentalized pathways to build up isoprene units. The co-existence of these pathways in the cytosol and in plastids might permit the synthesis of many vital compounds, being essential for a sessile organism. While substrate exchange across membranes has been shown for a variety of plant species, lack of complementation of strong phenotypes, resulting from inactivation of either the cytosolic pathway (growth and development defects) or the plastidial pathway (pigment bleaching), seems to be surprising at first sight. Hundreds of isoprenoids have been analyzed to determine their biosynthetic origins. It can be concluded that in angiosperms, under standard growth conditions, C₂₀-phytyl moieties, C₃₀-triterpenes and C₄₀-carotenoids are made nearly exclusively within compartmentalized pathways, while mixed origins are widespread for other types of isoprenoid-derived molecules. It seems likely that this coexistence is essential for the interaction of plants with their environment. A major purpose of this review is to summarize such observations, especially within an ecological and functional context and with some emphasis on regulation. This latter aspect still requires more work and present conclusions are preliminary, although some general features seem to exist.
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Affiliation(s)
- Andréa Hemmerlin
- Institut de Biologie Moléculaire des Plantes du Centre National de la Recherche Scientifique, IBMP-CNRS-UPR2357, Université de Strasbourg, 28 Rue Goethe, F-67083 Strasbourg Cedex, France.
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15
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Lipavská H, Masková P, Vojvodová P. Regulatory dephosphorylation of CDK at G₂/M in plants: yeast mitotic phosphatase cdc25 induces cytokinin-like effects in transgenic tobacco morphogenesis. ANNALS OF BOTANY 2011; 107:1071-86. [PMID: 21339187 PMCID: PMC3091802 DOI: 10.1093/aob/mcr016] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Revised: 11/02/2010] [Accepted: 12/03/2010] [Indexed: 05/07/2023]
Abstract
BACKGROUND During the last three decades, the cell cycle and its control by cyclin-dependent kinases (CDKs) have been extensively studied in eukaryotes. This endeavour has produced an overall picture that basic mechanisms seem to be largely conserved among all eukaryotes. The intricate regulation of CDK activities includes, among others, CDK activation by CDC25 phosphatase at G₂/M. In plants, however, studies of this regulation have lagged behind as a plant Cdc25 homologue or other unrelated phosphatase active at G₂/M have not yet been identified. SCOPE Failure to identify a plant mitotic CDK activatory phosphatase led to characterization of the effects of alien cdc25 gene expression in plants. Tobacco, expressing the Schizosaccharomyces pombe mitotic activator gene, Spcdc25, exhibited morphological, developmental and biochemical changes when compared with wild type (WT) and, importantly, increased CDK dephosphorylation at G₂/M. Besides changes in leaf shape, internode length and root development, in day-neutral tobacco there was dramatically earlier onset of flowering with a disturbed acropetal floral capacity gradient typical of WT. In vitro, de novo organ formation revealed substantially earlier and more abundant formation of shoot primordia on Spcdc25 tobacco stem segments grown on shoot-inducing media when compared with WT. Moreover, in contrast to WT, stem segments from transgenic plants formed shoots even without application of exogenous growth regulator. Spcdc25-expressing BY-2 cells exhibited a reduced mitotic cell size due to a shortening of the G₂ phase together with high activity of cyclin-dependent kinase, NtCDKB1, in early S-phase, S/G₂ and early M-phase. Spcdc25-expressing tobacco ('Samsun') cell suspension cultures showed a clustered, more circular, cell phenotype compared with chains of elongated WT cells, and increased content of starch and soluble sugars. Taken together, Spcdc25 expression had cytokinin-like effects on the characteristics studied, although determination of endogenous cytokinin levels revealed a dramatic decrease in Spcdc25 transgenics. CONCLUSIONS The data gained using the plants expressing yeast mitotic activator, Spcdc25, clearly argue for the existence and importance of activatory dephosphorylation at G₂/M transition and its interaction with cytokinin signalling in plants. The observed cytokinin-like effects of Spcdc25 expression are consistent with the concept of interaction between cell cycle regulators and phytohormones during plant development. The G₂/M control of the plant cell cycle, however, remains an elusive issue as doubts persist about the mode of activatory dephosphorylation, which in other eukaryotes is provided by Cdc25 phosphatase serving as a final all-or-nothing mitosis regulator.
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Affiliation(s)
- Helena Lipavská
- Department of Experimental Plant Biology, Faculty of Science, Charles University in Prague, Viničná 5, Prague 2, Czech Republic.
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16
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Tang J, Kobayashi K, Suzuki M, Matsumoto S, Muranaka T. The mitochondrial PPR protein LOVASTATIN INSENSITIVE 1 plays regulatory roles in cytosolic and plastidial isoprenoid biosynthesis through RNA editing. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 61:456-66. [PMID: 19929879 DOI: 10.1111/j.1365-313x.2009.04082.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Unlike animals, plants synthesize isoprenoids via two pathways, the cytosolic mevalonate (MVA) pathway and the plastidial 2-C-methyl-d-erythritol-4-phosphate (MEP) pathway. Little information is known about the mechanisms that regulate these complex biosynthetic networks over multiple organelles. To understand such regulatory mechanisms of the biosynthesis of isoprenoids in plants, we previously characterized the Arabidopsis mutant, lovastatin insensitive 1 (loi1), which is resistant to lovastatin and clomazone, specific inhibitors of the MVA and MEP pathways, respectively. LOI1 encodes a pentatricopeptide repeat (PPR) protein localized in mitochondria that is thought to have RNA binding ability and function in post-transcriptional regulation of mitochondrial gene expression. LOI1 belongs to the DYW subclass of PPR proteins, which is hypothesized to be correlated with RNA editing. As a result of analysis of RNA editing of mitochondrial genes in loi1, a defect in RNA editing of three genes, nad4, ccb203 and cox3, was identified in loi1. These genes are related to the respiratory chain. Wild type (WT) treated with some respiration inhibitors mimicked the loi1 phenotype. Interestingly, HMG-CoA reductase activity of WT treated with lovastatin combined with antimycin A, an inhibitor of complex III in the respiratory chain, was higher than that of WT treated with only lovastatin, despite the lack of alteration of transcript or protein levels of HMGR. These results suggest that HMGR enzyme activity is regulated through the respiratory cytochrome pathway. Although various mechanisms exist for isoprenoid biosynthesis, our studies demonstrate the novel possibility that mitochondrial respiration plays potentially regulatory roles in isoprenoid biosynthesis.
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Affiliation(s)
- Jianwei Tang
- RIKEN Plant Science Center, 1-7-22, Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
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17
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Suzuki M, Nakagawa S, Kamide Y, Kobayashi K, Ohyama K, Hashinokuchi H, Kiuchi R, Saito K, Muranaka T, Nagata N. Complete blockage of the mevalonate pathway results in male gametophyte lethality. JOURNAL OF EXPERIMENTAL BOTANY 2009; 60:2055-64. [PMID: 19363204 PMCID: PMC2682496 DOI: 10.1093/jxb/erp073] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2008] [Revised: 02/23/2009] [Accepted: 02/23/2009] [Indexed: 05/20/2023]
Abstract
Plants have two isoprenoid biosynthetic pathways: the cytosolic mevalonate (MVA) pathway and the plastidic 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway. Since the discovery of the MEP pathway, possible metabolic cross-talk between these pathways has prompted intense research. Although many studies have shown the existence of such cross-talk using feeding experiments, it remains to be determined if native cross-talk, rather than exogenously applied metabolites, can compensate for complete blockage of the MVA pathway. Previously, Arabidopsis mutants for HMG1 and HMG2 encoding HMG-CoA reductase (HMGR) were isolated. Although it was shown that HMGR1 is a functional HMGR, the enzyme activity of HMGR2 has not been confirmed. It is demonstrated here that HMG2 encodes a functional reductase with similar activity to HMGR1, using enzyme assays and complementation experiments. To estimate the contribution of native cross-talk, an attempt was made to block the MVA pathway by making double mutants lacking both HMG1 and HMG2, but no double homozygotes were detected in the progeny of self-pollinated HMG1/hmg1 hmg2/hmg2 plants. hmg1 hmg2 male gametophytes appeared to be lethal based on crossing experiments, and microscopy indicated that approximately 50% of the microspores from the HMG1/hmg1 hmg2/hmg2 plant appeared shrunken and exhibited poorly defined endoplasmic reticulum membranes. In situ hybridization showed that HMG1 transcripts were expressed in both the tapetum and microspores, while HMG2 mRNA appeared only in microspores. It is concluded that native cross-talk from the plastid cannot compensate for complete blockage of the MVA pathway, at least during male gametophyte development, because either HMG1 or HMG2 is required for male gametophyte development.
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Affiliation(s)
- Masashi Suzuki
- RIKEN Plant Science Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
| | - Shoko Nakagawa
- RIKEN Plant Science Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
- Graduate School of Science, Japan Women's University, 2-8-1, Mejirodai, Bunkyo-ku, Tokyo, 112-8681 Japan
| | - Yukiko Kamide
- RIKEN Plant Science Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
| | - Keiko Kobayashi
- RIKEN Plant Science Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
| | - Kiyoshi Ohyama
- RIKEN Plant Science Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
| | - Hiromi Hashinokuchi
- RIKEN Plant Science Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
| | - Reiko Kiuchi
- RIKEN Plant Science Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
| | - Kazuki Saito
- RIKEN Plant Science Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
- Graduate School of Pharmaceutical Sciences, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, Chiba, 263-8522 Japan
| | - Toshiya Muranaka
- RIKEN Plant Science Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
- Kihara Institute for Biological Research, Yokohama City University, 641-12, Maioka-cho, Totsuka-ku, Yokohama, Kanagawa, 244-0813 Japan
| | - Noriko Nagata
- Graduate School of Science, Japan Women's University, 2-8-1, Mejirodai, Bunkyo-ku, Tokyo, 112-8681 Japan
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18
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Kevei Z, Lougnon G, Mergaert P, Horváth GV, Kereszt A, Jayaraman D, Zaman N, Marcel F, Regulski K, Kiss GB, Kondorosi A, Endre G, Kondorosi E, Ané JM. 3-hydroxy-3-methylglutaryl coenzyme a reductase 1 interacts with NORK and is crucial for nodulation in Medicago truncatula. THE PLANT CELL 2007; 19:3974-89. [PMID: 18156218 PMCID: PMC2217646 DOI: 10.1105/tpc.107.053975] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2007] [Revised: 11/08/2007] [Accepted: 11/29/2007] [Indexed: 05/18/2023]
Abstract
NORK in legumes encodes a receptor-like kinase that is required for Nod factor signaling and root nodule development. Using Medicago truncatula NORK as bait in a yeast two-hybrid assay, we identified 3-hydroxy-3-methylglutaryl CoA reductase 1 (Mt HMGR1) as a NORK interacting partner. HMGR1 belongs to a multigene family in M. truncatula, and different HMGR isoforms are key enzymes in the mevalonate biosynthetic pathway leading to the production of a diverse array of isoprenoid compounds. Testing other HMGR members revealed a specific interaction between NORK and HMGR1. Mutagenesis and deletion analysis showed that this interaction requires the cytosolic active kinase domain of NORK and the cytosolic catalytic domain of HMGR1. NORK homologs from Lotus japonicus and Sesbania rostrata also interacted with Mt HMGR1, but homologous nonsymbiotic kinases of M. truncatula did not. Pharmacological inhibition of HMGR activities decreased nodule number and delayed nodulation, supporting the importance of the mevalonate pathway in symbiotic development. Decreasing HMGR1 expression in M. truncatula transgenic roots by RNA interference led to a dramatic decrease in nodulation, confirming that HMGR1 is essential for nodule development. Recruitment of HMGR1 by NORK could be required for production of specific isoprenoid compounds, such as cytokinins, phytosteroids, or isoprenoid moieties involved in modification of signaling proteins.
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Affiliation(s)
- Zoltán Kevei
- Institut des Sciences du Végétal, Centre National de la Recherche Scientifique, Unité Propre de Recherche 2355, 91198 Gif-sur-Yvette Cedex, France
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19
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Manzano D, Busquets A, Closa M, Hoyerová K, Schaller H, Kamínek M, Arró M, Ferrer A. Overexpression of farnesyl diphosphate synthase in Arabidopsis mitochondria triggers light-dependent lesion formation and alters cytokinin homeostasis. PLANT MOLECULAR BIOLOGY 2006; 61:195-213. [PMID: 16786301 DOI: 10.1007/s11103-006-6263-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2005] [Accepted: 12/31/2005] [Indexed: 05/10/2023]
Abstract
To investigate the role of mitochondrial farnesyl diphosphate synthase (FPS) in plant isoprenoid biosynthesis we characterized transgenic Arabidopsis thaliana plants overexpressing FPS1L isoform. This overexpressed protein was properly targeted to mitochondria yielding a mature and active form of the enzyme of 40 kDa. Leaves from transgenic plants grown under continuous light exhibited symptoms of chlorosis and cell death correlating to H(2)O(2) accumulation, and leaves detached from the same plants displayed accelerated senescence. Overexpression of FPS in mitochondria also led to altered leaf cytokinin profile, with a reduction in the contents of physiologically active trans-zeatin- and isopentenyladenine-type cytokinins and their corresponding riboside monophosphates as well as enhanced levels of cis-zeatin 7-glucoside and storage cytokinin O-glucosides. Overexpression of 3-hydroxy-3-methylglutaryl coenzyme A reductase did not prevent chlorosis in plants overexpressing FPS1L, but did rescue accelerated senescence of detached leaves and restored wild-type levels of cytokinins. We propose that the overexpression of FPS1L leads to an enhanced uptake and metabolism of mevalonic acid-derived isopentenyl diphosphate and/or dimethylallyl diphosphate by mitochondria, thereby altering cytokinin homeostasis and causing a mitochondrial dysfunction that renders plants more sensitive to the oxidative stress induced by continuous light.
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Affiliation(s)
- David Manzano
- Departament de Bioquímica i Biologia Molecular, Facultat de Farmàcia, Universitat de Barcelona, Spain
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20
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Orchard CB, Siciliano I, Sorrell DA, Marchbank A, Rogers HJ, Francis D, Herbert RJ, Suchomelova P, Lipavska H, Azmi A, Van Onckelen H. Tobacco BY-2 cells expressing fission yeast cdc25 bypass a G2/M block on the cell cycle. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2005; 44:290-9. [PMID: 16212607 DOI: 10.1111/j.1365-313x.2005.02524.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The mitotic inducer gene from Schizosaccharomyces pombe, Spcdc25, was used as a tool to investigate regulation of G2/M in higher plants using the BY-2 (Nicotiana tabacum) cell line as a model. Spcdc25-expressing BY-2 cells exhibited a reduced mitotic cell size through a shortening of the G2 phase. The cells often formed isodiametric double files both in BY-2 cells and in cell suspensions derived from 35S::Spcdc25 tobacco plants. In Spcdc25-expressing cells, the tobacco cyclin-dependent kinase, NtCDKB1, showed high activity in early S phase, S/G2 and early M phase, whereas in empty vector cells CDKB1 activity was transiently high in early S phase but thereafter remained lower. Spcdc25-expressing cells also bypassed a block on G2/M imposed by the cytokinin biosynthetic inhibitor lovastatin (LVS). Surprisingly, cytokinins were at remarkably low levels in Spcdc25-expressing cells compared with the empty vector, explaining why these cells retained mitotic competence despite the presence of LVS. In conclusion, synchronised Spcdc25-expressing BY-2 cells divided prematurely at a small cell size, and they exhibited premature, but sustained, CDKB1 activity even though endogenous cytokinins were virtually undetectable.
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Affiliation(s)
- Craig B Orchard
- School of Biosciences, Cardiff University, PO Box 915, Cardiff CF10 3TL, UK
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21
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Kwade Z, Swiatek A, Azmi A, Goossens A, Inzé D, Van Onckelen H, Roef L. Identification of four adenosine kinase isoforms in tobacco By-2 cells and their putative role in the cell cycle-regulated cytokinin metabolism. J Biol Chem 2005; 280:17512-9. [PMID: 15731114 DOI: 10.1074/jbc.m411428200] [Citation(s) in RCA: 40] [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
Adenosine kinase (ADK), a key enzyme in the regulation of the intracellular level of adenosine is also speculated to be responsible for the conversion of cytokinin ribosides to their respective nucleotides. To elucidate the role of ADK in the cytokinin metabolism of tobacco BY-2 cells (Nicotiana tabacum cv. "Bright Yellow-2"; TBY-2), we have identified and characterized the full-length cDNAs encoding four ADK isoforms of N. tabacum and determined their catalytic properties. The four TBY-2 ADK isoforms (designated 1S, 2S, 1T, and 2T) display a high affinity for both adenosine (Km 1.88-7.30 microm) and three distinct types of cytokinin ribosides: isopentenyladenosine; zeatin riboside; and dihydrozeatin riboside (Km 0.30-8.71 microm). The Vmax/Km values suggest that ADK2S exhibits in vitro an overall higher efficiency in the metabolism of cytokinin ribosides than the other three isoforms. The expression pattern of NtADK genes is modulated significantly during the cell cycle. We suggest that the increased transcript accumulation of NtADK coupled to an increased ADK activity just prior to mitosis is associated with a very active cytokinin metabolism at that phase of the cell cycle of synchronized TBY-2 cells.
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Affiliation(s)
- Zuzanna Kwade
- Laboratory of Plant Biochemistry and Physiology, Department of Biology, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk, Belgium
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22
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Hartig K, Beck E. Endogenous cytokinin oscillations control cell cycle progression of tobacco BY-2 cells. PLANT BIOLOGY (STUTTGART, GERMANY) 2005; 7:33-40. [PMID: 15666212 DOI: 10.1055/s-2004-830474] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The significance of cytokinins for the progression of the cell cycle is well known. Cytokinins contribute to the control of the expression of D-cyclins and other cell cycle genes, but knowledge as to how they affect the progression of the cell cycle is still limited. Highly synchronized tobacco BY-2 cells with clearly defined cell cycle stages were employed to determine cytokinin patterns in detail throughout the entire cycle. Concentrations of trans-zeatin, and of some other cytokinins, oscillated during the course of the cell cycle, increasing substantially at all four phase transitions and decreasing again to a minimum value during the course of each subsequent phase. Addition of exogenous cytokinins or inhibition of cytokinin biosynthesis promoted the progression of the cell cycle when the effects of these manipulations intensified the endogenous fluctuations, whereas the progression of the cycle was retarded when the amplitude of the fluctuations was decreased. The results show that the attainment of low concentrations of cytokinins is as important as the transient increases in concentration for a controlled progression from one phase of the cell cycle to the next. Cytokinin oxidase/dehydrogenase activity also showed fluctuations during the course of the cell cycle, the timing of which could at least partly explain oscillations of cytokinin levels. The activities of the enzyme were sufficient to account for the rates of cytokinin disappearance observed subsequent to a phase transition.
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Affiliation(s)
- K Hartig
- Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, 95440 Bayreuth, Germany.
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23
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Manzano D, Fernández-Busquets X, Schaller H, González V, Boronat A, Arró M, Ferrer A. The metabolic imbalance underlying lesion formation in Arabidopsis thaliana overexpressing farnesyl diphosphate synthase (isoform 1S) leads to oxidative stress and is triggered by the developmental decline of endogenous HMGR activity. PLANTA 2004; 219:982-992. [PMID: 15605175 DOI: 10.1007/s00425-004-1301-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2003] [Accepted: 04/16/2004] [Indexed: 05/24/2023]
Abstract
Overexpression of Arabidopsis thaliana farnesyl diphosphate synthase isoform 1S (FPS1S) in transgenic A. thaliana (L.) Heynh. leads to necrotic lesion formation in leaves in planta and to premature senescence in detached leaves [A. Masferrer et al. (2002) Plant J 30:123-132]. Here we report that leaves of plants overexpressing FPS1S with symptoms of necrosis show increased H2O2 formation and induction of both the pathogenesis-related 1 (PR-1) and the alternative oxidase 1a (AOX1a) genes. These findings indicate that plants overexpressing FPS1S should be considered as lesion-mimic mutants and lead us to propose that H2O2 is the main inducing agent of necrosis in these plants. The onset of necrosis appears in a developmentally regulated manner that correlates with the developmental decline of endogenous 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) activity. Accordingly, constitutive overexpression of HMGR in plants overexpressing FPS1S prevents both necrosis and premature senescence. These observations demonstrate that both phenotypes are due to an insufficient supply of mevalonic acid and support the notion that the metabolic imbalance associated with FPS1S overexpression is, in fact, triggered by the developmental decline of HMGR activity. We also show that overexpression of FPS1S alleviates growth inhibition caused by overexpression of the catalytic domain of isoform HMGR1S. Overall, our results reinforce the view that the levels of specific intermediates of the mevalonic acid pathway must be strictly controlled, particularly those located at branch-point positions, in order to avoid deleterious effects on plant growth and development.
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Affiliation(s)
- David Manzano
- Departament de Bioquímica i Biologia Molecular, Facultat de Farmàcia, Universitat de Barcelona, Av. Diagonal 643, 08028, Spain
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24
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Hemmerlin A, Gerber E, Feldtrauer JF, Wentzinger L, Hartmann MA, Tritsch D, Hoeffler JF, Rohmer M, Bach TJ. A review of tobacco BY-2 cells as an excellent system to study the synthesis and function of sterols and other isoprenoids. Lipids 2004; 39:723-35. [PMID: 15638240 DOI: 10.1007/s11745-004-1289-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
In plants, two pathways are utilized for the synthesis of isopentenyl diphosphate (IPP), the universal precursor for isoprenoid biosynthesis. In this paper we review findings and observations made primarily with tobacco BY-2 cells (TBY-2), which have proven to be an excellent system in which to study the two biosynthetic pathways. A major advantage of these cells as an experimental system is their ability to readily take up specific inhibitors and stably- and/or radiolabeled precursors. This permits the functional elucidation of the role of isoprenoid end products and intermediates. Because TBY-2 cells undergo rapid cell division and can be synchronized within the cell cycle, they constitute a highly suitable test system for determination of those isoprenoids and intermediates that act as cell cycle inhibitors, thus giving an indication of which branches of the isoprenoid pathway are essential. Through chemical complementation; and use of precursors, intracellular compartmentation can be elucidated, as well as the extent to which the plastidial and cytosolic pathways contribute to the syntheses of specific groups of isoprenoids (e.g., sterols) via exchange of intermediates across membranes. These topics are discussed in the context of the pertinent literature.
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Affiliation(s)
- Andréa Hemmerlin
- Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire des Plantes (UPR 2357), Département Fonctions et Biosynthèse des Isoprénoïdes, Université Louis Pasteur, F-67083 Strasbourg, France
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25
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Suzuki M, Kamide Y, Nagata N, Seki H, Ohyama K, Kato H, Masuda K, Sato S, Kato T, Tabata S, Yoshida S, Muranaka T. Loss of function of 3-hydroxy-3-methylglutaryl coenzyme A reductase 1 (HMG1) in Arabidopsis leads to dwarfing, early senescence and male sterility, and reduced sterol levels. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2004; 37:750-761. [PMID: 14871314 DOI: 10.1111/j.1365-313x.2004.02003.x] [Citation(s) in RCA: 128] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
3-Hydroxy-3-methylglutaryl-CoA reductase (HMGR) catalyzes the first committed step in the cytosolic isoprenoid biosynthesis pathway in higher plants. To understand the contribution of HMGR to plant development, we isolated T-DNA insertion mutants for HMG1 and HMG2. The hmg1 and hmg2 mutants were both more sensitive than the wild type (WT) to lovastatin, an inhibitor of HMGR. The hmg2 mutant showed no visible phenotype under normal growth conditions. In contrast, the hmg1 mutant exhibited dwarfing, early senescence, and sterility. Expression of senescence-associated genes 12 (SAG12), a marker gene for senescence, was induced in the hmg1 mutant at an earlier stage than in the WT. Levels of trans-cytokinins--hormones known to inhibit senescence--were not lower in hmg1. The mutant did not have the typical appearance of brassinosteroid (BR)-deficient mutants, except for a dwarf phenotype, because of the suppression of cell elongation. The expression of several genes involved in cell elongation was suppressed in hmg1. WT plants treated exogenously with inhibitors of sterol biosynthesis had similar gene expression and sterility characteristics as the hmg1 mutants. Pleiotropic phenotypes were rescued by feeding with squalene, the precursor of sterols and triterpenoids. The sterol levels in hmg1 mutants were lower than in the WT. These findings suggest that HMG1 plays a critical role in triterpene biosynthesis, and that sterols and/or triterpenoids contribute to cell elongation, senescence, and fertility.
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Affiliation(s)
- Masashi Suzuki
- Plant Science Center, RIKEN, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
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26
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Boiten H, Azmi A, Dillen W, De Schepper S, Debergh P, Gerats T, Van Onckelen H, Prinsen E. The Rg-1 encoded regeneration capacity of tomato is not related to an altered cytokinin homeostasis. THE NEW PHYTOLOGIST 2004; 161:761-771. [PMID: 33873729 DOI: 10.1111/j.1469-8137.2004.00993.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
• Cytokinin (CK) metabolism was analyzed in tomato (Lycopersicon esculentum) Rg-1 hybrids during in vitro shoot organogenesis from root explants. • Data were obtained by combining physicochemical analysis with quantification and in situ detection methods. • Although exogenous zeatin is added in all classical regeneration protocols, we show here that regenerating (Rg+ ) tomato explants did not require an exogenous CK source for regeneration. Irrespective of the presence or absence of exogenous zeatin, the endogenous CK levels were not affected by Rg-1 in the initial explants or in the early callus phase. In a later stage, and related to the presence of numerous shoots, the Rg+ explants showed much lower endogenous CK concentrations than the nonregenerating (rg- ) explants. Cells of rg- explants were not able to differentiate, despite their high endogenous CK content, and did not respond to exogenously applied CKs. • We show that the insensitivity of rg- explants to a hormonal signal, normally initiating regeneration, is not related to an altered endogenous CK metabolism. We therefore postulate that Rg-1 action involves a regeneration-specific CK receptor or a regeneration-specific CK signal transduction pathway.
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Affiliation(s)
- Hilde Boiten
- Laboratory of Plant Biochemistry and Physiology, Department of Biology, University of Antwerp (UA), B-2610 Antwerp, Belgium
| | - Abdelkrim Azmi
- Laboratory of Plant Biochemistry and Physiology, Department of Biology, University of Antwerp (UA), B-2610 Antwerp, Belgium
| | - Willy Dillen
- Department of Plant Systems Biology, University of Ghent (RUG), B-9000 Ghent, Belgium
- Present address: Crop Design, Technologiepark 3, B-9052 Zwijnaarde, Belgium
| | - Sandra De Schepper
- Laboratory of Horticulture and Plant Biotechnology, Department of Plant Production, University of Ghent (RUG), B-9000 Ghent, Belgium
| | - Pierre Debergh
- Laboratory of Horticulture and Plant Biotechnology, Department of Plant Production, University of Ghent (RUG), B-9000 Ghent, Belgium
| | - Tom Gerats
- Department of Plant Systems Biology, University of Ghent (RUG), B-9000 Ghent, Belgium
- Present address: Laboratory of Plant Genetics, Department of Experimental Botany, University of Nijmegen (KUN), Toernooiveld 1, NL-6525 ED Nijmegen, The Netherlands
| | - Harry Van Onckelen
- Laboratory of Plant Biochemistry and Physiology, Department of Biology, University of Antwerp (UA), B-2610 Antwerp, Belgium
| | - Els Prinsen
- Laboratory of Plant Biochemistry and Physiology, Department of Biology, University of Antwerp (UA), B-2610 Antwerp, Belgium
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27
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Kasahara H, Takei K, Ueda N, Hishiyama S, Yamaya T, Kamiya Y, Yamaguchi S, Sakakibara H. Distinct isoprenoid origins of cis- and trans-zeatin biosyntheses in Arabidopsis. J Biol Chem 2004; 279:14049-54. [PMID: 14726522 DOI: 10.1074/jbc.m314195200] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Plants produce the common isoprenoid precursors isopentenyl diphosphate and dimethylallyl diphosphate (DMAPP) through the methylerythritol phosphate (MEP) pathway in plastids and the mevalonate (MVA) pathway in the cytosol. To assess which pathways contribute DMAPP for cytokinin biosynthesis, metabolites from each isoprenoid pathway were selectively labeled with (13)C in Arabidopsis seedlings. Efficient (13)C labeling was achieved by blocking the endogenous pathway genetically or chemically during the feed of a (13)C labeled precursor specific to the MEP or MVA pathways. Liquid chromatography-mass spectrometry analysis demonstrated that the prenyl group of trans-zeatin (tZ) and isopentenyladenine is mainly produced through the MEP pathway. In comparison, a large fraction of the prenyl group of cis-zeatin (cZ) derivatives was provided by the MVA pathway. When expressed as fusion proteins with green fluorescent protein in Arabidopsis cells, four adenosine phosphate-isopentenyltransferases (AtIPT1, AtIPT3, AtIPT5, and AtIPT8) were found in plastids, in agreement with the idea that the MEP pathway primarily provides DMAPP to tZ and isopentenyladenine. On the other hand, AtIPT2, a tRNA isopentenyltransferase, was detected in the cytosol. Because the prenylated adenine moiety of tRNA is usually of the cZ type, the formation of cZ in Arabidopsis seedlings might involve the transfer of DMAPP from the MVA pathway to tRNA. Distinct origins of large proportions of DMAPP for tZ and cZ biosynthesis suggest that plants are able to separately modulate the level of these cytokinin species.
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Affiliation(s)
- Hiroyuki Kasahara
- Laboratory for Cellular Growth and Development, Plant Science Center, RIKEN, Yokohoma, Japan
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28
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29
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Hemmerlin A, Hoeffler JF, Meyer O, Tritsch D, Kagan IA, Grosdemange-Billiard C, Rohmer M, Bach TJ. Cross-talk between the cytosolic mevalonate and the plastidial methylerythritol phosphate pathways in tobacco bright yellow-2 cells. J Biol Chem 2003; 278:26666-76. [PMID: 12736259 DOI: 10.1074/jbc.m302526200] [Citation(s) in RCA: 252] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In plants, two pathways are utilized for the synthesis of isopentenyl diphosphate, the universal precursor for isoprenoid biosynthesis. The key enzyme of the cytoplasmic mevalonic acid (MVA) pathway is 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR). Treatment of Tobacco Bright Yellow-2 (TBY-2) cells by the HMGR-specific inhibitor mevinolin led to growth reduction and induction of apparent HMGR activity, in parallel to an increase in protein representing two HMGR isozymes. Maximum induction was observed at 24 h. 1-Deoxy-d-xylulose (DX), the dephosphorylated first precursor of the plastidial 2-C-methyl-d-erythritol 4-phosphate (MEP) pathway, complemented growth inhibition by mevinolin in the low millimolar concentration range. Furthermore, DX partially re-established feedback repression of mevinolin-induced HMGR activity. Incorporation studies with [1,1,1,4-2H4]DX showed that sterols, normally derived from MVA, in the presence of mevinolin are synthesized via the MEP pathway. Fosmidomycin, an inhibitor of 1-deoxy-d-xylulose-5-phosphate reductoisomerase, the second enzyme of the MEP pathway, was utilized to study the reverse complementation. Growth inhibition by fosmidomycin of TBY-2 cells could be partially overcome by MVA. Chemical complementation was further substantiated by incorporation of [2-13C]MVA into plastoquinone, representative of plastidial isoprenoids. Best rates of incorporation of exogenous stably labeled precursors were observed in the presence of both inhibitors, thereby avoiding internal isotope dilution.
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Affiliation(s)
- Andréa Hemmerlin
- CNRS, UPR 2357, Institut de Biologie Moléculaire des Plantes, 28 Rue Goethe, 67083 Strasbourg Cedex, France
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30
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Miyazawa Y, Kato H, Muranaka T, Yoshida S. Amyloplast formation in cultured tobacco BY-2 cells requires a high cytokinin content. PLANT & CELL PHYSIOLOGY 2002; 43:1534-41. [PMID: 12514251 DOI: 10.1093/pcp/pcf173] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
When cytokinin-autonomous tobacco BY-2 cell cultures are transferred into 2,4-dichlorophenoxyacetic acid (2,4-D)-deprived medium, amyloplast development is initiated. Using this in vitro amyloplast-inducing system, the role of cytokinins in amyloplast formation was investigated. We show that addition of lovastatin, an inhibitor of mevalonate synthesis, to amyloplast-inducing medium reduced starch accumulation. Microscopic observation also revealed that lovastatin treatment decreased starch deposition; however, the overall morphologies of cells and plastids were less affected than control cell cultures. In addition, lovastatin lowered the transcription level of the ADP-glucose pyrophosphorylase small subunit (AgpS) gene. Application of mevalonate or zeatin dramatically restored the decrease in starch deposition, and restored AgpS mRNA accumulation. Moreover, addition of other molecules with cytokinin activity, such as adenine- and phenylurea-type compounds, restored starch accumulation and AgpS transcript levels, whereas other isopentenyl pyrophosphate-derived phytohormones did not. Liquid chromatography-mass spectrometry/mass spectrometry quantification of endogenous cytokinins revealed that endogenous cytokinins increased when BY-2 cells were transferred into 2,4-D-deprived medium from conventional medium containing 2,4-D. In addition, lovastatin treatment decreased endogenous cytokinins to some extent when cultured under 2,4-D-deprived conditions. Our results suggest that both 2,4-D deprivation and an increase in endogenous cytokinins have important roles in accelerating the changes in plastid morphology, starch accumulation, and AgpS gene expression.
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Affiliation(s)
- Yutaka Miyazawa
- Plant Functions Laboratory, RIKEN, 2-1, Hirosawa, Wako, Saitama, 351-0198 Japan.
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31
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Masferrer A, Arró M, Manzano D, Schaller H, Fernández-Busquets X, Moncaleán P, Fernández B, Cunillera N, Boronat A, Ferrer A. Overexpression of Arabidopsis thaliana farnesyl diphosphate synthase (FPS1S) in transgenic Arabidopsis induces a cell death/senescence-like response and reduced cytokinin levels. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2002; 30:123-132. [PMID: 12000449 DOI: 10.1046/j.1365-313x.2002.01273.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
To investigate the contribution of farnesyl diphosphate synthase (FPS) to the overall control of the mevalonic acid pathway in plants, we have generated transgenic Arabidopsis thaliana overexpressing the Arabidopsis FPS1S isoform. Despite high levels of FPS activity in transgenic plants (8- to 12-fold as compared to wild-type plants), the content of sterols and the levels of 3-hydroxy-3-methylglutaryl-CoA reductase activity in leaves were similar to those in control plants. Plants overexpressing FPS1S showed a cell death/senescence-like phenotype and grew less vigorously than wild-type plants. The onset and the severity of these phenotypes directly correlated with the levels of FPS activity. In leaves of plants with increased FPS activity, the expression of the senescence activated gene SAG12 was prematurely induced. Transgenic plants grown in the presence of either mevalonic acid (MVA) or the cytokinin 2-isopentenyladenine (2-iP) recovered the wild-type phenotype. Quantification of endogenous cytokinins demonstrated that FPS1S overexpression specifically reduces the levels of endogenous zeatin-type cytokinins in leaves. Altogether these results support the notion that increasing FPS activity without a concomitant increase of MVA production leads to a reduction of IPP and DMAPP available for cytokinin biosynthesis. The reduced cytokinin levels would be, at least in part, responsible for the phenotypic alterations observed in the transgenic plants. The finding that wild-type and transgenic plants accumulated similar increased amounts of sterols when grown in the presence of exogenous MVA suggests that FPS1S is not limiting for sterol biosynthesis.
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Affiliation(s)
- Angela Masferrer
- Departament de Bioquímica i Biologia Molecular, Facultat de Farmàcia, Universitat de Barcelona, Avinguda, Diagonal 643, 08028-Barcelona, Spain
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32
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Geelen DN, Inzé DG. A bright future for the bright yellow-2 cell culture. PLANT PHYSIOLOGY 2001; 127:1375-1379. [PMID: 11743076 DOI: 10.1104/pp.010708] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Affiliation(s)
- D N Geelen
- Department of Molecular Genetics, Flanders Interuniversity Institute for Biotechnology, Ghent University, K.L. Ledeganckstraat 35, B-9000 Gent, Belgium
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Hemmerlin A, Bach TJ. Farnesol-induced cell death and stimulation of 3-hydroxy-3-methylglutaryl-coenzyme A reductase activity in tobacco cv bright yellow-2 cells. PLANT PHYSIOLOGY 2000; 123:1257-68. [PMID: 10938345 PMCID: PMC59085 DOI: 10.1104/pp.123.4.1257] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2000] [Accepted: 02/21/2000] [Indexed: 05/20/2023]
Abstract
Growth inhibition of tobacco (Nicotiana tabacum L. cv Bright Yellow-2) cells by mevinolin, a specific inhibitor of 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR) could be partially overcome by the addition of farnesol. However, farnesol alone inhibited cell division and growth as measured by determination of fresh weight increase. When 7-d-old tobacco cv Bright Yellow-2 cells were diluted 40-fold into fresh culture, the cells exhibited a dose-dependent sensitivity to farnesol, with 25 microM sufficient to cause 100% cell death, as measured by different staining techniques, cytometry, and monitoring of fragmentation of genomic DNA. Cells were less sensitive to the effects of farnesol when diluted only 4-fold. Farnesol was absorbed by the cells, as examined by [1-(3)H]farnesol uptake, with a greater relative enrichment by the more diluted cells. Both mevinolin and farnesol treatments stimulated apparent HMGR activity. The stimulation by farnesol was also reflected in corresponding changes in the steady-state levels of HMGR mRNA and enzyme protein with respect to HMGR gene expression and enzyme protein accumulation.
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Affiliation(s)
- A Hemmerlin
- Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire des Plantes, Département Isoprénoïdes, Institut de Botanique, Université Louis Pasteur, 28 rue Goethe, F-67083 Strasbourg, France
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Laureys F, Smets R, Lenjou M, Van Bockstaele D, Inzé D, Van Onckelen H. A low content in zeatin type cytokinins is not restrictive for the occurrence of G1/S transition in tobacco BY-2 cells. FEBS Lett 1999; 460:123-8. [PMID: 10571073 DOI: 10.1016/s0014-5793(99)01264-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Theories on the importance of cytokinins in G1/S transition control are manifold and contradictory. By establishing a double A(phi-PZ block, maximal synchronization of a BY-2 suspension culture was obtained to investigate the effect of cytokinin depletion on G1/S transition. Lovastatin was used as a specific inhibitor of cytokinin biosynthesis. Flow cytometry showed that the G1/S transition occurred regardless of the cytokinin drop. This observation indicates an extremely low dose requiry for that stage of the cell cycle. It is very likely that precisely the downregulation of zeatin type cytokinins matters for the G1/S transition to occur, since cytokinin addition at early G1 blocked the cycle at G1/S.
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Affiliation(s)
- F Laureys
- Department of Biology, Universiteit Antwerpen, Wilrijk, Belgium
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Laureys F, Dewitte W, Witters E, Van Montagu M, Inzé D, Van Onckelen H. Zeatin is indispensable for the G2-M transition in tobacco BY-2 cells. FEBS Lett 1998; 426:29-32. [PMID: 9598972 DOI: 10.1016/s0014-5793(98)00297-x] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The importance of N6-isoprenoid cytokinins in the G2-M transition of Nicotiana tabacum BY-2 cells was investigated. Both cytokinin biosynthesis and entry in mitosis were partially blocked by application at early or late G2 of lovastatin (10 microM), an inhibitor of mevalonic acid synthesis. LC-MS/MS quantification of endogenous cytokinins proved that lovastatin affects cytokinin biosynthesis by inhibiting HMG-CoA reductase. Out of eight different aminopurines and a synthetic auxin tested for their ability to override lovastatin inhibition of mitosis, only zeatin was active. Our data point to a key role for a well-defined cytokinin (here, zeatin) in the G2-M transition of tobacco BY-2 cells.
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Affiliation(s)
- F Laureys
- Laboratorium voor Plantenbiochemie en -fysiologie, Department of Biology, Universiteit Antwerpen (UIA), Wilrijk, Belgium
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Hemmerlin A, Bach TJ. Effects of mevinolin on cell cycle progression and viability of tobacco BY-2 cells. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 1998; 14:65-74. [PMID: 15494054 DOI: 10.1046/j.1365-313x.1998.00095.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Mevinolin, an inhibitor of 3-hydroxy-3-methylglutaryl-CoA reductase, was used to study the importance of mevalonic acid (MVA) for cell cycle progression of tobacco (Nicotiana tabacum L.) BY-2 cells. After treatment with 5 microM mevinolin, the cell cycle progression was completely blocked and two cell populations accumulated (80% in phase G0/G1 and 20% in G2/M). The arrest could be released by subsequent addition of MVA. Effects were compared to those caused by aphidicolin, an inhibitor of alpha-like DNA polymerases that blocks cell cycle at the entry of the S phase. The 80% proportion of mevinolin-treated TBY-2 cells was clearly arrested before the aphidicolin-inducible block. By the aid of a double-blocking technique, it was shown that the mevinolin-induced cell arrest of highly synchronized cells was due to interaction with a control point located at the mitotic telophase/entry G1 phase. Depending on the developmental stage, mevinolin induced rapid cell death in a considerable percentage of cells. Mevinolin treatment led to a partial synchronization, as shown by the increase in mitotic index. The following decrease was correlated with the above-mentioned induction of cell death.
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Affiliation(s)
- A Hemmerlin
- Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire des Plantes, Département d'Enzymologie Cellulaire et Moléculaire, Institut de Botanique, Université Louis Pasteur, 28 rue Goethe, F67083 Strasbourg, France
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Cowan AK, Moore-Gordon CS, Bertling I, Wolstenholme BN. Metabolic Control of Avocado Fruit Growth (Isoprenoid Growth Regulators and the Reaction Catalyzed by 3-Hydroxy-3-Methylglutaryl Coenzyme A Reductase). PLANT PHYSIOLOGY 1997; 114:511-518. [PMID: 12223724 PMCID: PMC158331 DOI: 10.1104/pp.114.2.511] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The effect of isoprenoid growth regulators on avocado (Persea americana Mill. cv Hass) fruit growth and mesocarp 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) activity was investigated during the course of fruit ontogeny. Both normal and small-fruit phenotypes were used to probe the interaction between the end products of isoprenoid biosynthesis and the activity of HMGR in the metabolic control of avocado fruit growth. Kinetic analysis of the changes in both cell number and size revealed that growth was limited by cell number in phenotypically small fruit. In small fruit a 70% reduction in microsomal HMGR activity was associated with an increased mesocarp abscisic acid (ABA) concentration. Application of mevastatin, a competitive inhibitor of HMGR, reduced the growth of normal fruit and increased mesocarp ABA concentration. These effects were reversed by co-treatment of fruit with mevalonic acid lactone, isopentenyladenine, or N-(2-chloro-4-pyridyl)-N-phenylurea, but were not significantly affected by either gibberellic acid or stigmasterol. However, stigmasterol appeared to partially restore fruit growth when co-injected with mevastatin in either phase II or III of fruit growth. In vivo application of ABA reduced fruit growth and mesocarp HMGR activity and accelerated fruit abscission, effects that were reversed by co-treatment with isopentenyladenine. Together, these observations indicate that ABA accumulation down-regulates mesocarp HMGR activity and fruit growth, and that in situ cytokinin biosynthesis modulates these effects during phase I of fruit ontogeny, whereas both cytokinins and sterols seem to perform this function during the later phases.
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Affiliation(s)
- A. K. Cowan
- Department of Horticultural Science, University of Natal, Pietermaritzburg, Private Bag X01, Scottsville 3209, South Africa
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Redig P, Shaul O, Inze D, Van Montagu M, Van Onckelen H. Levels of endogenous cytokinins, indole-3-acetic acid and abscisic acid during the cell cycle of synchronized tobacco BY-2 cells. FEBS Lett 1996; 391:175-80. [PMID: 8706911 DOI: 10.1016/0014-5793(96)00728-4] [Citation(s) in RCA: 121] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Correlation between cell cycle progression and endogenous levels of plant hormones was studied in synchronized tobacco BY-2 cell suspension cultures. Sixteen different cytokinins, indole-3-acetic acid (IAA) and abscisic acid (ABA) were extracted using solid-phase anion exchange chromatography in combination with immunoaffinity purification, and quantified by mass spectrometry. No significant correlation could be identified for IAA and ABA. In contrast, there were sharp peaks in the levels of specific cytokinins (zeatin- and dihydrozeatin-type) at the end of the S phase and during mitosis. The levels of other cytokinins analyzed, including zeatins N- and O-glucosides, remained low, suggesting that the increased amounts of their corresponding non-glucosylated form resulted from de novo synthesis. These findings suggest that zeatin- and dihydrozeatin-type cytokinins might play a specific regulatory role in the progression of the plant cell cycle. One hypothesis to explain cytokinin action is based on a specific interaction with kinases that regulate cell cycle progression, as has been recently shown for the cytokinin analogue olomoucine.
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Affiliation(s)
- P Redig
- Department Biologie, Universitaire Instelling Antwerpen, Belgium
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Morehead TA, Biermann BJ, Crowell DN, Randall SK. Changes in Protein Isoprenylation during the Growth of Suspension-Cultured Tobacco Cells. PLANT PHYSIOLOGY 1995; 109:277-284. [PMID: 12228594 PMCID: PMC157586 DOI: 10.1104/pp.109.1.277] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Isoprenylation facilitates the association of proteins with intracellular membranes and/or other proteins. In mammalian and yeast cells, isoprenylated proteins are involved in signal transduction, cell division, organization of the cytoskeleton, and vesicular transport. Recently, protein isoprenylation has been demonstrated in higher plants, but little is currently known about the functions of isoprenylated plant proteins. We report that inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase (lovastatin) or prenyl:protein transferases (perilly alcohol) severely impair the growth of cultured tobacco (Nicotiana tabacum) cells but only when added within the first 2 d following transfer to fresh medium, before any increase in culture volume is detectable. This "window" of sensitivity to inhibitors of protein isoprenylation correlates temporally with an increase in [14C]mevalonate incorporation into tobacco cell proteins in vitro. We have also observed a marked increase in farnesyl:protein transferase activity at this early time in the growth of tobacco cultures. In contrast, type I geranylgeranyl:protein transferase activity does not change significantly during culture growth. Although these events coincide with the replication of DNA, I [mu]M lovastatin-treated cells are capable of DNA synthesis, suggesting that lovastatin-induced cell growth arrest is not due to inhibition of DNA replication. Together, these data support the hypothesis that protein isoprenylation is necessary for the early stages of growth of tobacco cultures.
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Affiliation(s)
- T. A. Morehead
- Biology Department, Indiana University-Purdue University at Indianapolis, 723 West Michigan Street, Indianapolis, Indiana 46202-5132
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Arvy MP, Imbault N, Naudascher F, Thiersault M, Doireau P. 2,4-D and alkaloid accumulation in periwinkle cell suspensions. Biochimie 1994; 76:410-6. [PMID: 7849107 DOI: 10.1016/0300-9084(94)90117-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Omission of 2,4-D from culture medium during one subculture of Catharanthus roseus cells, strain C20, resulted in an increased alkaloid accumulation, without effect on growth. Alkaloid accumulation, rather than growth, seemed to be more sensitive to 2,4-D. 2,4-D inhibited alkaloid accumulation essentially during growth phase, but its inhibitory effect during this period was partially reversible. As this reversibility was underlined only during the stationary phase, this suggested that this action could be situated upstream in a terpenoid non-specific pathway. 2,4-D feeding showed that inhibition is weaker and weaker as the alkaloid accumulation period proceeds. Auxin action during this period could take place downstream in specific alkaloid pathways. The lower alkaloid accumulation obtained after loganic acid feeding compared to that obtained with secologanin and loganin could indicate that loganic acid methylation should be one of the 2,4-D target(s).
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Affiliation(s)
- M P Arvy
- Laboratoire de Physiologie Végétale, Faculté des Sciences, Tours, France
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Randall SK, Marshall MS, Crowell DN. Protein isoprenylation in suspension-cultured tobacco cells. THE PLANT CELL 1993; 5:433-42. [PMID: 8485402 PMCID: PMC160282 DOI: 10.1105/tpc.5.4.433] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Many mammalian and yeast proteins, including small ras-like GTP binding proteins, heterotrimeric G protein gamma subunits, and nuclear lamins, have been shown to be covalently linked to isoprenoid derivatives of mevalonic acid. Isoprenylation of these proteins is required for their assembly into membranes and, hence, for their biological activity. In this report, it is shown that cultured tobacco cells, when pretreated with an inhibitor of endogenous mevalonic acid synthesis (lovastatin), incorporate radioactivity from 14C-mevalonic acid into proteins. Most of these proteins are membrane associated, and many are similar in mass to mammalian ras-like GTP binding proteins and nuclear lamins. Furthermore, it is shown that tobacco cell extracts catalyze the transfer of radioactivity from 3H-farnesyl pyrophosphate and 3H-geranylgeranyl pyrophosphate to protein substrates in vitro. These studies indicate the presence of at least two distinct prenyl:protein transferases in tobacco extracts: one that utilizes farnesyl pyrophosphate and preferentially modifies a substrate protein with a CAIM carboxy terminus (farnesyl:protein transferase) and one that utilizes geranylgeranyl pyrophosphate and preferentially modifies a substrate protein with a CAIL carboxy terminus (geranylgeranyl:protein transferase type I). This work provides a basis for future work on the role of protein isoprenylation in plant cell growth, signal transduction, and membrane biogenesis.
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Affiliation(s)
- S K Randall
- Department of Biology, Indiana University-Purdue University, Indianapolis 46202-5132
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