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Tang X, Liu R, Mei Y, Wang D, He K, Wang NN. Identification of Key Ubiquitination Sites Involved in the Proteasomal Degradation of AtACS7 in Arabidopsis. Int J Mol Sci 2024; 25:2931. [PMID: 38474174 PMCID: PMC10931761 DOI: 10.3390/ijms25052931] [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: 01/22/2024] [Revised: 02/23/2024] [Accepted: 02/29/2024] [Indexed: 03/14/2024] Open
Abstract
The gaseous hormone ethylene plays pivotal roles in plant growth and development. The rate-limiting enzyme of ethylene biosynthesis in seed plants is 1-aminocyclopropane-1-carboxylic acid (ACC) synthase (ACS). ACS proteins are encoded by a multigene family and the expression of ACS genes is highly regulated, especially at a post-translational level. AtACS7, the only type III ACS in Arabidopsis, is degraded in a 26S proteasome-dependent pathway. Here, by using liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) analysis, two lysine residues of AtACS7, lys285 (K285) and lys366 (K366), were revealed to be ubiquitin-modified in young, light-grown Arabidopsis seedlings but not in etiolated seedlings. Deubiquitylation-mimicking mutations of these residues significantly increased the stability of the AtACS7K285RK366R mutant protein in cell-free degradation assays. All results suggest that K285 and K366 are the major ubiquitination sites on AtACS7, providing deeper insights into the post-translational regulation of AtACS7 in Arabidopsis.
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Affiliation(s)
| | | | | | | | - Kaixuan He
- Tianjin Key Laboratory of Protein Sciences, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Ning Ning Wang
- Tianjin Key Laboratory of Protein Sciences, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin 300071, China
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2
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Arenas F, López-García Á, Berná LM, Morte A, Navarro-Ródenas A. Desert truffle mycorrhizosphere harbors organic acid releasing plant growth-promoting rhizobacteria, essentially during the truffle fruiting season. MYCORRHIZA 2022; 32:193-202. [PMID: 35043240 PMCID: PMC8907101 DOI: 10.1007/s00572-021-01067-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 12/28/2021] [Indexed: 06/14/2023]
Abstract
Desert truffle is becoming a new crop in semiarid areas. Climatic parameters and the presence of microorganisms influence the host plant physiology and alter desert truffle production. Desert truffle plants present a typical summer deciduous plant phenology divided into four stages: summer dormancy, autumn bud break, winter photosynthetic activity, and spring fruiting. We hypothesize that the bacterial community associated with desert truffle plants will show a seasonal trend linked to their plant growth-promoting rhizobacteria (PGPR) traits. This information will provide us with a better understanding about its potential role in this symbiosis and possible management implementations. Bacteria were isolated from root-adhering soil at the four described seasons. A total of 417 isolated bacteria were phenotypically and biochemically characterized and gathered by molecular analysis into 68 operational taxonomic units (OTUs). They were further characterized for PGPR traits such as indole acetic acid production, siderophore production, calcium phosphate solubilization, and ACCD (1-amino-cyclopropane-1-carboxilatedeaminase) activity. These PGPR traits were used to infer functional PGPR diversity and cultivable bacterial OTU composition at different phenological moments. The different seasons induced shifts in the OTU composition linked to their PGPR traits. Summer was the phenological stage with the lowest microbial diversity and PGPR functions, whereas spring was the most active one. Among the PGPR traits analyzed, P-solubilizing rhizobacteria were harbored in the mycorrhizosphere during desert truffle fruiting in spring.
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Affiliation(s)
- Francisco Arenas
- Dpto. Biología Vegetal (Botánica), Facultad de Biología, Universidad de Murcia, CEIR "Campus Mare Nostrum", Campus de Espinardo, 30100, Murcia, Spain
| | - Álvaro López-García
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín-CSIC, Calle Prof. Albareda, 18008, Granada, Spain
- Department of Animal Biology, Plant Biology and Ecology, Universidad de Jaén, Jaén, Spain
- Instituto Interuniversitario de Investigación del Sistema Tierra en Andalucía (IISTA), Av. del Mediterráneo, 18006, Granada, S/N, Spain
| | - Luis Miguel Berná
- Dpto. Biología Vegetal (Botánica), Facultad de Biología, Universidad de Murcia, CEIR "Campus Mare Nostrum", Campus de Espinardo, 30100, Murcia, Spain
| | - Asunción Morte
- Dpto. Biología Vegetal (Botánica), Facultad de Biología, Universidad de Murcia, CEIR "Campus Mare Nostrum", Campus de Espinardo, 30100, Murcia, Spain
| | - Alfonso Navarro-Ródenas
- Dpto. Biología Vegetal (Botánica), Facultad de Biología, Universidad de Murcia, CEIR "Campus Mare Nostrum", Campus de Espinardo, 30100, Murcia, Spain.
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3
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Wu W, Du K, Kang X, Wei H. The diverse roles of cytokinins in regulating leaf development. HORTICULTURE RESEARCH 2021; 8:118. [PMID: 34059666 PMCID: PMC8167137 DOI: 10.1038/s41438-021-00558-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 02/11/2021] [Accepted: 03/22/2021] [Indexed: 05/24/2023]
Abstract
Leaves provide energy for plants, and consequently for animals, through photosynthesis. Despite their important functions, plant leaf developmental processes and their underlying mechanisms have not been well characterized. Here, we provide a holistic description of leaf developmental processes that is centered on cytokinins and their signaling functions. Cytokinins maintain the growth potential (pluripotency) of shoot apical meristems, which provide stem cells for the generation of leaf primordia during the initial stage of leaf formation; cytokinins and auxins, as well as their interaction, determine the phyllotaxis pattern. The activities of cytokinins in various regions of the leaf, especially at the margins, collectively determine the final leaf morphology (e.g., simple or compound). The area of a leaf is generally determined by the number and size of the cells in the leaf. Cytokinins promote cell division and increase cell expansion during the proliferation and expansion stages of leaf cell development, respectively. During leaf senescence, cytokinins reduce sugar accumulation, increase chlorophyll synthesis, and prolong the leaf photosynthetic period. We also briefly describe the roles of other hormones, including auxin and ethylene, during the whole leaf developmental process. In this study, we review the regulatory roles of cytokinins in various leaf developmental stages, with a focus on cytokinin metabolism and signal transduction processes, in order to shed light on the molecular mechanisms underlying leaf development.
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Affiliation(s)
- Wenqi Wu
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing, PR China
| | - Kang Du
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing, PR China
- National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing, China
- Key Laboratory for Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, China
| | - Xiangyang Kang
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing, PR China.
- National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing, China.
- Key Laboratory for Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, China.
| | - Hairong Wei
- College of Forest Resources and Environmental Science, Michigan Technological University, Houghton, MI, USA.
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Bengoa Luoni S, Astigueta FH, Nicosia S, Moschen S, Fernandez P, Heinz R. Transcription Factors Associated with Leaf Senescence in Crops. PLANTS (BASEL, SWITZERLAND) 2019; 8:E411. [PMID: 31614987 PMCID: PMC6843677 DOI: 10.3390/plants8100411] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 08/21/2019] [Accepted: 08/23/2019] [Indexed: 12/13/2022]
Abstract
Leaf senescence is a complex mechanism controlled by multiple genetic and environmental variables. Different crops present a delay in leaf senescence with an important impact on grain yield trough the maintenance of the photosynthetic leaf area during the reproductive stage. Additionally, because of the temporal gap between the onset and phenotypic detection of the senescence process, candidate genes are key tools to enable the early detection of this process. In this sense and given the importance of some transcription factors as hub genes in senescence pathways, we present a comprehensive review on senescence-associated transcription factors, in model plant species and in agronomic relevant crops. This review will contribute to the knowledge of leaf senescence process in crops, thus providing a valuable tool to assist molecular crop breeding.
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Affiliation(s)
- Sofia Bengoa Luoni
- Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Autónoma de Buenos Aires 1425, Argentina.
| | - Francisco H Astigueta
- Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Autónoma de Buenos Aires 1425, Argentina.
- Escuela de Ciencia y Tecnología, Universidad Nacional de San Martín, San Martín, Buenos Aires 1650, Argentina.
| | - Salvador Nicosia
- Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Autónoma de Buenos Aires 1425, Argentina.
- Universidad Nacional de Lujan, Cruce Rutas Nac. 5 y 7, Lujan, Buenos Aires 6700, Argentina.
| | - Sebastian Moschen
- Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Autónoma de Buenos Aires 1425, Argentina.
- Instituto Nacional de Tecnología Agropecuaria, Estación Experimental Agropecuaria Famaillá, Tucumán 4142, Argentina.
| | - Paula Fernandez
- Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Autónoma de Buenos Aires 1425, Argentina.
- Escuela de Ciencia y Tecnología, Universidad Nacional de San Martín, San Martín, Buenos Aires 1650, Argentina.
- Instituto de Agrobiotecnología y Biología Molecular (INTA-CONICET), Instituto de Biotecnología, Centro de Investigaciones en Ciencias Agronómicas y Veterinarias, Instituto Nacional de Tecnología Agropecuaria, Hurlingham, Buenos Aires 1686, Argentina.
| | - Ruth Heinz
- Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Autónoma de Buenos Aires 1425, Argentina.
- Instituto de Agrobiotecnología y Biología Molecular (INTA-CONICET), Instituto de Biotecnología, Centro de Investigaciones en Ciencias Agronómicas y Veterinarias, Instituto Nacional de Tecnología Agropecuaria, Hurlingham, Buenos Aires 1686, Argentina.
- Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires 1428, Argentina.
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Lv SF, Jia MZ, Zhang SS, Han S, Jiang J. The dependence of leaf senescence on the balance between 1-aminocyclopropane-1-carboxylate acid synthase 1 (ACS1)-catalysed ACC generation and nitric oxide-associated 1 (NOS1)-dependent NO accumulation in Arabidopsis. PLANT BIOLOGY (STUTTGART, GERMANY) 2019; 21:595-603. [PMID: 30734982 DOI: 10.1111/plb.12970] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Accepted: 02/04/2019] [Indexed: 05/29/2023]
Abstract
Ethylene and nitric oxide (NO) act as endogenous regulators during leaf senescence. Levels of ethylene or its precursor 1-aminocyclopropane-1-carboxylate acid (ACC) depend on the activity of ACC synthases (ACS), and NO production is controlled by NO-associated 1 (NOA1). However, the integration mechanisms of ACS and NOA1 activity still need to be explored during leaf senescence. Here, using experimental techniques, such as physiological and molecular detection, liquid chromatography-tandem mass spectrometry and fluorescence measurement, we investigated the relevant mechanisms. Our observations showed that the loss-of-function acs1-1 mutant ameliorated age- or dark-induced leaf senescence syndrome, such as yellowing and loss of chlorophyll, that acs1-1 reduced ACC accumulation mainly in mature leaves and that acs1-1-promoted NOA1 expression and NO accumulation mainly in juvenile leaves, when compared with the wild type (WT). But the leaf senescence promoted by the NO-deficient noa1 mutant was not involved in ACS1 expression. There was a similar sharp reduction of ACS1 and NOA1 expression with the increase in WT leaf age, and this inflection point appeared in mature leaves and coincided with the onset of leaf senescence. These findings suggest that NOA1-dependent NO accumulation blocked the ACS1-induced onset of leaf senescence, and that ACS1 activity corresponds to the onset of leaf senescence in Arabidopsis.
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Affiliation(s)
- S-F Lv
- State Key Laboratory of Cotton Biology, College of Life Sciences, Henan University, Kaifeng, China
- College of Agriculture, Henan University of Science and Technology, Luoyang, China
| | - M-Z Jia
- State Key Laboratory of Cotton Biology, College of Life Sciences, Henan University, Kaifeng, China
| | - S-S Zhang
- State Key Laboratory of Cotton Biology, College of Life Sciences, Henan University, Kaifeng, China
| | - S Han
- State Key Laboratory of Cotton Biology, College of Life Sciences, Henan University, Kaifeng, China
| | - J Jiang
- State Key Laboratory of Cotton Biology, College of Life Sciences, Henan University, Kaifeng, China
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Cui X, Cen H, Guan C, Tian D, Liu H, Zhang Y. Photosynthesis capacity diversified by leaf structural and physiological regulation between upland and lowland switchgrass in different growth stages. FUNCTIONAL PLANT BIOLOGY : FPB 2019; 47:38-49. [PMID: 31578165 DOI: 10.1071/fp19086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 08/21/2019] [Indexed: 06/10/2023]
Abstract
Understanding and enhancing switchgrass (Panicum virgatum L.) photosynthesis will help to improve yield and quality for bio-industrial applications on cellulosic biofuel production. In the present study, leaf anatomical traits and physiological characteristics related to photosynthetic capacity of both lowland and upland switchgrass were recorded from four varieties across the vegetative, elongation and reproductive growth stages. Compared with the upland varieties, the lowland switchgrass showed 37-59, 22-64 and 27-73% higher performance on height, stem and leaf over all three growth stages. Leaf anatomical traits indicated that the leaves of lowland varieties provided more space for carbon assimilation and transportation caused by enhanced cell proliferation with more bundles sheath cells and larger contact areas between the bundle sheath and mesophyll cells (CAMB), which lead to the 32-72% higher photosynthetic capacity found in the lowland varieties during vegetative and elongation growth. However, photosynthetic capacity became 22-51% higher in the upland varieties during the reproductive stage, which is attributed to more photosynthetic pigment. In conclusion, lowland varieties gain a photosynthetic advantage with enhanced bundle sheath cell proliferation, while the upland varieties preserved more photosynthetic pigments. Our study provides new insights for improving the yield in crops by enhancing photosynthesis with anatomical and physiological strategies.
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Affiliation(s)
- Xin Cui
- College of Grassland Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Huifang Cen
- College of Grassland Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Cong Guan
- College of Grassland Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Danyang Tian
- College of Grassland Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Huayue Liu
- College of Grassland Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Yunwei Zhang
- College of Grassland Science and Technology, China Agricultural University, Beijing, 100193, China; and Corresponding author.
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7
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Abstract
As a representative form of plant senescence, leaf senescence has received the most attention during the last two decades. In this chapter we summarize the initiation of leaf senescence by various internal and external signals, the progression of senescence including switches in gene expression, as well as changes at the biochemical and cellular levels during leaf senescence. Impacts of leaf senescence in agriculture and genetic approaches that have been used in manipulating leaf senescence of crop plants are discussed.
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Affiliation(s)
- Akhtar Ali
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, Shandong, China.,Nuclear Institute for Food and Agriculture, Peshawar, Pakistan
| | - Xiaoming Gao
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, Shandong, China
| | - Yongfeng Guo
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, Shandong, China.
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8
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Iqbal N, Khan NA, Ferrante A, Trivellini A, Francini A, Khan MIR. Ethylene Role in Plant Growth, Development and Senescence: Interaction with Other Phytohormones. FRONTIERS IN PLANT SCIENCE 2017; 8:475. [PMID: 28421102 PMCID: PMC5378820 DOI: 10.3389/fpls.2017.00475] [Citation(s) in RCA: 304] [Impact Index Per Article: 43.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 03/17/2017] [Indexed: 05/18/2023]
Abstract
The complex juvenile/maturity transition during a plant's life cycle includes growth, reproduction, and senescence of its fundamental organs: leaves, flowers, and fruits. Growth and senescence of leaves, flowers, and fruits involve several genetic networks where the phytohormone ethylene plays a key role, together with other hormones, integrating different signals and allowing the onset of conditions favorable for stage progression, reproductive success and organ longevity. Changes in ethylene level, its perception, and the hormonal crosstalk directly or indirectly regulate the lifespan of plants. The present review focused on ethylene's role in the development and senescence processes in leaves, flowers and fruits, paying special attention to the complex networks of ethylene crosstalk with other hormones. Moreover, aspects with limited information have been highlighted for future research, extending our understanding on the importance of ethylene during growth and senescence and boosting future research with the aim to improve the qualitative and quantitative traits of crops.
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Affiliation(s)
| | - Nafees A. Khan
- Plant Physiology and Biochemistry Laboratory, Department of Botany, Aligarh Muslim UniversityAligarh, India
| | - Antonio Ferrante
- Department of Agricultural and Environmental Sciences, Università degli Studi di MilanoMilano, Italy
| | - Alice Trivellini
- Institute of Life Sciences, Scuola Superiore Sant’AnnaPisa, Italy
| | | | - M. I. R. Khan
- Crop and Environmental Sciences Division, International Rice Research InstituteManila, Philippines
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Zhang Y, Feng L, Jiang H, Zhang Y, Zhang S. Different Proteome Profiles between Male and Female Populus cathayana Exposed to UV-B Radiation. FRONTIERS IN PLANT SCIENCE 2017; 8:320. [PMID: 28326097 PMCID: PMC5339244 DOI: 10.3389/fpls.2017.00320] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2016] [Accepted: 02/22/2017] [Indexed: 05/20/2023]
Abstract
With increasing altitude, solar UV-B radiation is enhanced. Based on the phenomenon of male-biased sex ratio of Populus cathayana Rehder in high altitude alpine area, we hypothesized that males have a faster and more sophisticated responsive mechanism to high UV-B radiation than that of females. Our previous studies have shown sexually different responses to high UV-B radiation were existed in P. cathayana at the morphological, physiological, and transcriptomic levels. However, the responses at the proteomic level remain unclear. In this study, an isobaric tag for relative and absolute quantification (iTRAQ)-based quantitative proteome analysis was performed in P. cathayana females and males. A total of 2,405 proteins were identified, with 331 proteins defined as differentially expressed proteins (DEPs). Among of these, 79 and 138 DEPs were decreased and 47 and 107 DEPs were increased under high solar UV-B radiation in females and males, respectively. A bioinformatics analysis categorized the common responsive proteins in the sexes as related to carbohydrate and energy metabolism, translation/transcription/post-transcriptional modification, photosynthesis, and redox reactions. The responsive proteins that showed differences in sex were mainly those involved in amino acid metabolism, stress response, and translation/transcription/post-transcriptional modification. This study provides proteomic profiles that poplars responding to solar UV-B radiation, and it also provides new insights into differentially sex-related responses to UV-B radiation.
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Affiliation(s)
- Yunxiang Zhang
- Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of SciencesChengdu, China
- University of Chinese Academy of SciencesBeijing, China
| | - Lihua Feng
- Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of SciencesChengdu, China
- Institute of Evolution and the Department of Evolutionary and Environmental Biology, University of HaifaHaifa, Israel
| | - Hao Jiang
- Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of SciencesChengdu, China
| | - Yuanbin Zhang
- Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of SciencesChengdu, China
| | - Sheng Zhang
- Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of SciencesChengdu, China
- *Correspondence: Sheng Zhang
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10
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Root transcriptome of two contrasting indica rice cultivars uncovers regulators of root development and physiological responses. Sci Rep 2016; 6:39266. [PMID: 28000793 PMCID: PMC5175279 DOI: 10.1038/srep39266] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 11/21/2016] [Indexed: 12/12/2022] Open
Abstract
The huge variation in root system architecture (RSA) among different rice (Oryza sativa) cultivars is conferred by their genetic makeup and different growth or climatic conditions. Unlike model plant Arabidopsis, the molecular basis of such variation in RSA is very poorly understood in rice. Cultivars with stable variation are valuable resources for identification of genes involved in RSA and related physiological traits. We have screened for RSA and identified two such indica rice cultivars, IR-64 (OsAS83) and IET-16348 (OsAS84), with stable contrasting RSA. OsAS84 produces robust RSA with more crown roots, lateral roots and root hairs than OsAS83. Using comparative root transcriptome analysis of these cultivars, we identified genes related to root development and different physiological responses like abiotic stress responses, hormone signaling, and nutrient acquisition or transport. The two cultivars differ in their response to salinity/dehydration stresses, phosphate/nitrogen deficiency, and different phytohormones. Differential expression of genes involved in salinity or dehydration response, nitrogen (N) transport, phosphate (Pi) starvation signaling, hormone signaling and root development underlies more resistance of OsAS84 towards abiotic stresses, Pi or N deficiency and its robust RSA. Thus our study uncovers gene-network involved in root development and abiotic stress responses in rice.
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Roldan M, Islam A, Dinh PTY, Leung S, McManus MT. Phosphate availability regulates ethylene biosynthesis gene expression and protein accumulation in white clover (Trifolium repens L.) roots. Biosci Rep 2016; 36:e00411. [PMID: 27737923 PMCID: PMC5293567 DOI: 10.1042/bsr20160148] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 10/11/2016] [Accepted: 10/13/2016] [Indexed: 01/23/2023] Open
Abstract
The expression and accumulation of members of the 1-aminocyclopropane-1-carboxylate (ACC) synthase (ACS) and ACC oxidase (ACO) gene families was examined in white clover roots grown in either Pi (phosphate) sufficient or Pi-deprived defined media. The accumulation of one ACO isoform, TR-ACO1, was positively influenced after only 1 h of exposure to low Pi, and this was maintained over a 7-day time-course. Up-regulation of TR-ACS1, TR-ACS2 and TR-ACS3 transcript abundance was also observed within 1 h of exposure to low Pi in different tissue regions of the roots, followed by a second increase in abundance of TR-ACS2 after 5-7 days of exposure. An increase in transcript abundance of TR-ACO1 and TR-ACO3, but not TR-ACO2, was observed after 1 h of exposure to low Pi, with a second increase in TR-ACO1 transcripts occurring after 2-5 days. These initial increases of the TR-ACS and TR-ACO transcript abundance occurred before the induction of Trifolium repens PHOSPHATE TRANSPORTER 1 (TR-PT1), and the addition of sodium phosphite did not up-regulate TR-ACS1 expression over 24 h. In situ hybridization revealed some overlap of TR-ACO mRNA accumulation, with TR-ACO1 and TR-ACO2 in the root tip regions, and TR-ACO1 and TR-ACO3 mRNA predominantly in the lateral root primordia. TR-ACO1p-driven GFP expression showed that activation of the TR-ACO1 promoter was initiated within 24 h of exposure to low Pi (as determined by GFP protein accumulation). These results suggest that the regulation of ethylene biosynthesis in white clover roots is biphasic in response to low Pi supply.
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Affiliation(s)
- Marissa Roldan
- Institute of Fundamental Sciences, Massey University, Private Bag 11222, Palmerston North 4474, New Zealand
| | - Afsana Islam
- Institute of Fundamental Sciences, Massey University, Private Bag 11222, Palmerston North 4474, New Zealand
| | - Phuong T Y Dinh
- Institute of Fundamental Sciences, Massey University, Private Bag 11222, Palmerston North 4474, New Zealand
| | - Susanna Leung
- Institute of Fundamental Sciences, Massey University, Private Bag 11222, Palmerston North 4474, New Zealand
| | - Michael T McManus
- Institute of Fundamental Sciences, Massey University, Private Bag 11222, Palmerston North 4474, New Zealand
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Kebrom TH, Mullet JE. Transcriptome Profiling of Tiller Buds Provides New Insights into PhyB Regulation of Tillering and Indeterminate Growth in Sorghum. PLANT PHYSIOLOGY 2016; 170:2232-50. [PMID: 26893475 PMCID: PMC4824614 DOI: 10.1104/pp.16.00014] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 02/13/2016] [Indexed: 05/04/2023]
Abstract
Phytochrome B (phyB) enables plants to modify shoot branching or tillering in response to varying light intensities and ratios of red and far-red light caused by shading and neighbor proximity. Tillering is inhibited in sorghum genotypes that lack phytochrome B (58M, phyB-1) until after floral initiation. The growth of tiller buds in the first leaf axil of wild-type (100M, PHYB) and phyB-1 sorghum genotypes is similar until 6 d after planting when buds of phyB-1 arrest growth, while wild-type buds continue growing and develop into tillers. Transcriptome analysis at this early stage of bud development identified numerous genes that were up to 50-fold differentially expressed in wild-type/phyB-1 buds. Up-regulation of terminal flower1, GA2oxidase, and TPPI could protect axillary meristems in phyB-1 from precocious floral induction and decrease bud sensitivity to sugar signals. After bud growth arrest in phyB-1, expression of dormancy-associated genes such as DRM1, GT1, AF1, and CKX1 increased and ENOD93, ACCoxidase, ARR3/6/9, CGA1, and SHY2 decreased. Continued bud outgrowth in wild-type was correlated with increased expression of genes encoding a SWEET transporter and cell wall invertases. The SWEET transporter may facilitate Suc unloading from the phloem to the apoplast where cell wall invertases generate monosaccharides for uptake and utilization to sustain bud outgrowth. Elevated expression of these genes was correlated with higher levels of cytokinin/sugar signaling in growing buds of wild-type plants.
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Affiliation(s)
- Tesfamichael H Kebrom
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843 (T.H.K., J.E.M.)
| | - John E Mullet
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843 (T.H.K., J.E.M.)
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Carman JG, Hole P, Salisbury FB, Bingham GE. Developmental, nutritional and hormonal anomalies of weightlessness-grown wheat. LIFE SCIENCES IN SPACE RESEARCH 2015; 6:59-68. [PMID: 26256629 DOI: 10.1016/j.lssr.2015.07.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 07/08/2015] [Accepted: 07/09/2015] [Indexed: 06/04/2023]
Abstract
The behavior of water in weightlessness, as occurs in orbiting spacecraft, presents multiple challenges for plant growth. Soils remain saturated, impeding aeration, and leaf surfaces remain wet, impeding gas exchange. Herein we report developmental and biochemical anomalies of "Super Dwarf" wheat (Triticum aestivum L.) grown aboard Space Station Mir during the 1996-97 "Greenhouse 2" experiment. Leaves of Mir-grown wheat were hyperhydric, senesced precociously and accumulated aromatic and branched-chain amino acids typical of tissues experiencing oxidative stress. The highest levels of stress-specific amino acids occurred in precociously-senescing leaves. Our results suggest that the leaf ventilation system of the Svet Greenhouse failed to remove sufficient boundary layer water, thus leading to poor gas exchange and onset of oxidative stress. As oxidative stress in plants has been observed in recent space-flight experiments, we recommend that percentage water content in apoplast free-spaces of leaves be used to evaluate leaf ventilation effectiveness. Mir-grown plants also tillered excessively. Crowns and culms of these plants contained low levels of abscisic acid but high levels of cytokinins. High ethylene levels may have suppressed abscisic acid synthesis, thus permitting cytokinins to accumulate and tillering to occur.
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Affiliation(s)
- J G Carman
- Department of Plants, Soils and Climate, Utah State University, Logan, UT 84322-4820, USA.
| | - P Hole
- Utah State University Analytical Laboratory, Logan, UT 84322-4830, USA.
| | - F B Salisbury
- Department of Plants, Soils and Climate, Utah State University, Logan, UT 84322-4820, USA.
| | - G E Bingham
- Space Dynamics Laboratory, Utah State University, 1695 North Research Park Way, Logan, UT 84341-1942, USA.
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Wilkinson S, Kudoyarova GR, Veselov DS, Arkhipova TN, Davies WJ. Plant hormone interactions: innovative targets for crop breeding and management. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:3499-509. [PMID: 22641615 DOI: 10.1093/jxb/ers148] [Citation(s) in RCA: 128] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Here we highlight how both the root and shoot environment impact on whole plant hormone balance, particularly under stresses such as soil drying, and relate hormone ratios and relative abundances to processes influencing plant performance and yield under both mild and more severe stress. We discuss evidence (i) that abscisic acid (ABA) and ethylene act antagonistically on grain-filling rate amongst other yield-impacting processes; (ii) that ABA's effectiveness as an agent of stomatal closure can be modulated by coincident ethylene or cytokinin accumulation; and (iii) that enhanced cytokinin production can increase growth and yield by improving foliar stay-green indices under stress, and by improving processes that impact grain-filling and number, and that this can be the result of altered relative abundances of cytokinin and ABA (and other hormones). We describe evidence and novel processes whereby these phenomena are/could be amenable to manipulation through genetic and management routes, such that plant performance and yield can be improved. We explore the possibility that a range of ABA-ethylene and ABA-cytokinin relative abundances could represent targets for breeding/managing for yield resilience under a spectrum of stress levels between severe and mild, and could circumvent some of the pitfalls so far encountered in the massive research effort towards breeding for increases in the complex trait of yield.
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Affiliation(s)
- Sally Wilkinson
- Lancaster Environment Centre, Lancaster University, Lancaster, UK.
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Feng BH, Wu B, Zhang CR, Huang X, Chen YF, Huang XL. Cloning and expression of 1-aminocyclopropane-1-carboxylate oxidase cDNA induced by thidiazuron during somatic embryogenesis of alfalfa (Medicago sativa). JOURNAL OF PLANT PHYSIOLOGY 2012; 169:176-82. [PMID: 22118816 DOI: 10.1016/j.jplph.2011.08.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 08/22/2011] [Accepted: 08/25/2011] [Indexed: 05/13/2023]
Abstract
Embryogenic callus (EC) induced from petioles of alfalfa (Medicago sativa L. cv. Jinnan) on B5h medium turned green, compact and non-embryogenic when the kinetin (KN) in the medium was replaced partially or completely by thidiazuron (TDZ). The application of CoCl₂, which is an inhibitor of 1-aminocyclopropane-1-carboxylate oxidase (ACO), counteracted the effect of TDZ. Ethylene has been shown to be involved in the modulation of TDZ-induced morphogenesis responses. However, very little is known about the genes involved in ethylene formation during somatic embryogenesis (SE). To investigate whether ethylene mediated by ACO is involved in the effect of TDZ on inhibition of embryogenic competence of the alfalfa callus. In this study we cloned full-length ACO cDNA from the alfalfa callus, named MsACO, and observed changes in this gene expression during callus formation and induction of SE under treatment with TDZ or TDZ plus CoCl₂. RNA blot analysis showed that during the EC subcultural period, the expression level of MsACO in EC was significantly increased on the 2nd day, rose to the highest level on the 8th day and remained at this high level until the 21st day. However, the ACO expression in the TDZ (0.93 μM)-treated callus was higher than in the EC especially on the 8th day. Moreover the ACO expression level increased with increasing TDZ concentration during the subcultural/maintenance period of the callus. It is worth noting that comparing the treatment with TDZ alone, the treatment with 0.93 μM TDZ plus 50 μM CoCl₂ reduced both of the ACO gene expressions and ACO activity in the treated callus. These results indicate that the effect of TDZ could be counteracted by CoCl₂ either on the ACO gene expression level or ACO activity. Thus, a TDZ inhibitory effect on embryogenic competence of alfalfa callus could be mediated by ACO gene expression.
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Affiliation(s)
- Bi-Hong Feng
- The Key Laboratory of Gene Engineering of the Ministry of Education, School of Life Sciences, Zhongshan (Sun Yat-sen) University, Guangzhou 510275, China
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Dorling SJ, Leung S, Anderson CWN, Albert NW, McManus MT. Changes in 1-aminocyclopropane-1-carboxlate (ACC) oxidase expression and enzyme activity in response to excess manganese in white clover (Trifolium repens L.). PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2011; 49:1013-9. [PMID: 21530288 DOI: 10.1016/j.plaphy.2011.04.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2011] [Accepted: 04/07/2011] [Indexed: 05/09/2023]
Abstract
To examine the effect on Mn treatment on the ACO gene family of white clover [Trifolium repens (L.) cv. Grasslands Challenge], rooted stolon cuttings were maintained in modified Hoaglands medium, at pH 5.4, containing either 5.2 μM Mn or 100 μM Mn over a 9-day time course. A significant uptake of Mn was observed in leaf tissue of plants grown in the 100 μM Mn treatment after 24 h and the content increased in these plants to reach 334 mg/kg DW at the conclusion of the time course. The growth of plants, measured as the petiole extension rate (PER), was significantly less in the 100 μM Mn treatment by day 9, while significantly less accumulation of leaf biomass was observed by day 7. The activity of a cell wall-associated H(2)O(2)-generating NADH peroxidase was shown to be higher in the 100 μM Mn treatment after day 5 of the time course while no significant difference in a H(2)O(2)-consuming guaiacol peroxidase activity was observed between the two Mn treatments. The expression of two leaf-associated ACC oxidase (ACO) genes, TR-ACO2 and TR-ACO3 was examined over the 9-day course but no difference between the two treatments was observed. In contrast, TR-ACO2 enzyme activity was measured and shown to decrease in the 100 μM Mn treatment after day 5 of the time course, with a concomitant decrease in TR-ACO2 accumulation, as determined by western analysis. Using 2DE and western analysis, evidence for post-translational modification of TR-ACO2 was observed.
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Affiliation(s)
- Sarah J Dorling
- Institute of Molecular Biosciences, Massey University, Private Bag 11222, Palmerston North, New Zealand
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17
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Du Z, Leung S, Dorling SJ, McManus MT. ACC oxidase (ACO) genes in Trifolium occidentale (L.) and their relationship to ACO genes in white clover (T. repens L.) and T. pallescens (L.). PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2011; 49:420-426. [PMID: 21320784 DOI: 10.1016/j.plaphy.2011.01.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Revised: 01/10/2011] [Accepted: 01/11/2011] [Indexed: 05/30/2023]
Abstract
The identification and expression of two ACC oxidase (ACO) genes during leaf development in Trifolium occidentale (L.), one of the putative ancestral genomes of the allotetraploid, T. repens (L.; white clover), is described. In common with observations made in T. repens, the ACO genes displayed differential expression, with a TR-ACO2-like gene (designated TO-ACO2) confined to developing and early mature-green leaf tissue while expression of a TR-ACO3-like gene (designated TO-ACO3) is highest in leaves at the onset and during senescence. Biochemical analysis of TO-ACO2 revealed that both accumulation of the protein (determined by western analysis with a TR-ACO2 antibody) and enzyme activity matched the transcriptional activity of TO-ACO2. Western analysis also revealed that the Tr-ACO2 antibody recognised a protein of 37 kDa as a putative TP-ACO2 in T. pallescens. The 3'-UTRs of TO-ACO2 and TO-ACO3 were then compared with the 3'-UTRs of a TR-ACO2-like and TR-ACO3-like gene from T. pallescens, the other proposed ancestral genome (or closely related to the ancestor) of T. repens, with identity values of 87.8% for the ACO2-like genes and 94.8% for the ACO3-like genes. Comparison of the 3'-UTRs of TO-ACO2 with a TO-ACO2-like gene in T. repens (designated TR(O)-ACO2) and TP-ACO2 with a TP-ACO2-like gene in T. repens (designated TR(P)-ACO2) revealed identities of 100% and 96.6%, respectively, lending good support to T. occidentale as one of the ancestral genomes of T. repens. A similar comparison of the 3'-UTRs of TO-ACO3 with a TO-ACO3-like gene in T. repens (designated TR(O)-ACO3) and TP-ACO3 with a TP-ACO3-like gene in T. repens (designated TR(P)-ACO3) revealed identities of 99.5% and 97.9%, respectively, again supporting T. occidentale as one of the ancestral genomes. Further, these data confirm that both TO-ACO-like and TP-ACO-like genes are expressed in the allotetraploid T. repens.
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Affiliation(s)
- Zhenning Du
- Institute of Molecular Biosciences, Massey University, Palmerston North, New Zealand
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18
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Veit B. Hormone mediated regulation of the shoot apical meristem. PLANT MOLECULAR BIOLOGY 2009; 69:397-408. [PMID: 18797999 DOI: 10.1007/s11103-008-9396-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2008] [Accepted: 08/28/2008] [Indexed: 05/08/2023]
Abstract
Recent work on hormone mediated regulation of the SAM is reviewed, emphasizing how combinations of genetic, molecular and modelling approaches have refined models based on classic experimental and physiological work. Special emphasis is given to newly described mechanisms that modulate the responsiveness of specific tissues to hormones and their potential to direct position dependent determination processes.
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Affiliation(s)
- Bruce Veit
- Forage Biotechnology, AgResearch, Private Bag 11008, Palmerston North, New Zealand.
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Binnie JE, McManus MT. Characterization of the 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase multigene family of Malus domestica Borkh. PHYTOCHEMISTRY 2009; 70:348-360. [PMID: 19223050 DOI: 10.1016/j.phytochem.2009.01.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2008] [Revised: 12/19/2008] [Accepted: 01/06/2009] [Indexed: 05/27/2023]
Abstract
Two 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase (ACO) genes have been cloned from RNA isolated from leaf tissue of apple (Malus domestica cv. Royal Gala). The genes, designated MD-ACO2 (with an ORF of 990bp) and MD-ACO3 (966bp) have been compared with a previously cloned gene of apple, MD-ACO1 (with an ORF of 942bp). MD-ACO1 and MD-ACO2 share a close nucleotide sequence identity of 93.9% in the ORF but diverge in the 3' untranslated regions (3'-UTR) (69.5%). In contrast, MD-ACO3 shares a lower sequence identity with both MD-ACO1 (78.5%) and MD-ACO2 (77.8%) in the ORF, and 68.4% (MD-ACO1) and 71% (MD-ACO2) in the 3'-UTR. Southern analysis confirmed that MD-ACO3 is encoded by a distinct gene, but the distinction between MD-ACO1 and MD-ACO2 is not as definitive. Gene expression analysis has shown that MD-ACO1 is restricted to fruit tissues, with optimal expression in ripening fruit, MD-ACO2 expression occurs more predominantly in younger fruit tissue, with some expression in young leaf tissue, while MD-ACO3 is expressed predominantly in young and mature leaf tissue, with less expression in young fruit tissue and least expression in ripening fruit. Protein accumulation studies using western analysis with specific antibodies raised to recombinant MD-ACO1 and MD-ACO3 produced in E. coli confirmed the accumulation of MD-ACO1 in mature fruit, and an absence of accumulation in leaf tissue. In contrast, MD-ACO3 accumulation occurred in younger leaf tissue, and in younger fruit tissue. Further, the expression of MD-ACO3 and accumulation of MD-ACO3 in leaf tissue is linked to fruit longevity. Analysis of the kinetic properties of the three apple ACOs using recombinant enzymes produced in E. coli revealed apparent Michaelis constants (K(m)) of 89.39 microM (MD-ACO1), 401.03 microM (MD-ACO2) and 244.5 microM (MD-ACO3) for the substrate ACC, catalytic constants (K(cat)) of 6.6x10(-2) (MD-ACO1), 3.44x10(-2) (Md-ACO2) and 9.14x10(-2) (MD-ACO3) and K(cat)/K(m) (microMs(-1)) values of 7.38x10(-4) microMs(-1) (MD-ACO1), 0.86x10(-4)Ms(-1) (MD-ACO2) and 3.8x10(-4) microMs(-1) (MD-ACO3). These results show that MD-ACO1, MD-ACO2 and MD-ACO3 are differentially expressed in apple fruit and leaf tissue, an expression pattern that is supported by some variation in kinetic properties.
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Affiliation(s)
- Jan E Binnie
- Institute of Molecular Biosciences, Massey University, Private Bag 11222, Palmerston North, New Zealand
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Pan G, Lou C. Isolation of an 1-aminocyclopropane-1-carboxylate oxidase gene from mulberry (Morus alba L.) and analysis of the function of this gene in plant development and stresses response. JOURNAL OF PLANT PHYSIOLOGY 2008; 165:1204-13. [PMID: 17997189 DOI: 10.1016/j.jplph.2007.02.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2006] [Revised: 02/11/2007] [Accepted: 02/14/2007] [Indexed: 05/24/2023]
Abstract
Mulberry (Morus alba) is an important crop tree involved in sericulture and pharmaceuticals. To further understand the development and the environmental adaptability mechanism of mulberry, a cDNA of the gene MaACO1 encoding 1-aminocyclopropane-1-carboxylate oxidase was isolated from mulberry. This was used to investigate stress-responsive expression in mulberry. Developmental expression of ACC oxidase in mulberry leaves and spatial expression in mulberry flowers were also investigated. Damage and low-temperature treatment promoted the expression of MaACO1 in mulberry. In leaves, expression of the MaACO1 gene increased in cotyledons and the lowest leaves with leaf development, but showed reduced levels in emerging leaves. In flowers, the pollinated stigma showed the highest expression level, followed by the unpollinated stigma, ovary, and immature flowers. These results suggest that high MaACO1 expression may be predominantly associated with tissue aging or senescence in mulberry.
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Affiliation(s)
- Gang Pan
- College of Animal Sciences, Zhejiang University, Hangzhou, PR China
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21
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Lemmens C, Boeck H, Zavalloni C, Nijs I, Ceulemans R. How is phenology of grassland species influenced by climate warming across a range of species richness? COMMUNITY ECOL 2008. [DOI: 10.1556/comec.9.2008.s.6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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McManus MT. Further examination of abscission zone cells as ethylene target cells in higher plants. ANNALS OF BOTANY 2008; 101:285-292. [PMID: 17965027 PMCID: PMC2711017 DOI: 10.1093/aob/mcm269] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2007] [Revised: 08/19/2007] [Accepted: 08/31/2007] [Indexed: 05/25/2023]
Abstract
BACKGROUND AND AIMS Two aspects of the competence of abscission zone cells as a specific class of hormone target cell are examined. The first is the competence of these target cells to respond to a remote stele-generated signal, and whether ethylene acts in concert with this signal to initiate abscission of the primary leaf in Phaseolus vulgaris. The second is to extend the concept of dual control of abscission cell competence. Can the concept of developmental memory that is retained by abscission cell of Phaseolus vulgaris post-separation in terms of the inductive/repressive control of beta-1,4-glucan endohydrolase (cellulase) activity exerted by ethylene/auxin be extended to the rachis abscission zone cells of Sambucus nigra? METHODS Abscission assays were performed using the leaf petiole-pulvinus explants of P. vulgaris with the distal pulvinus stele removed. These (-stele) explants do not separate when treated with ethylene and require a stele-generated signal from the distal pulvinus for separation at the leaf petiole-pulvinis abscission zone. Using these explants, the role of ethylene was examined, using the ethylene action blocker, 1-methyl cyclopropene, as well as the significance of the tissue from which the stele signal originates. Further, leaf rachis abscission explants were excised from the compound leaves of S. nigra, and changes in the activity of cellulase in response to added ethylene and auxin post-separation was examined. KEY RESULTS The use of (-stele) explants has confirmed that ethylene, with the stele-generated signal, is essential for abscission. Neither ethylene alone nor the stelar signal alone is sufficient. Further, in addition to the leaf pulvinus distal to the abscission zone, mid-rib tissue that is excised from senescent or green mid-rib tissue can also generate a competent stelar signal. Experiments with rachis abscission explants of S. nigra have shown that auxin, when added to cells post-separation can retard cellulase activity, with activity re-established with subsequent ethylene treatment. CONCLUSIONS The triggers that initiate and regulate the separation process are complex with, in bean leaves at least, the generation of a signal (or signals) from remote tissues, in concert with ethylene, a requisite part of the process. Once evoked, abscission cells maintain a developmental memory such that the induction/repression mediated by ethylene/auxin that is observed prior to separation is also retained by the cells post-separation.
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Affiliation(s)
- Michael T McManus
- Institute of Molecular Biosciences, Massey University, Private Bag 11-222, Palmerston North, New Zealand.
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Cumming M, Leung S, McCallum J, McManus MT. Complex formation between recombinant ATP sulfurylase and APS reductase of Allium cepa (L.). FEBS Lett 2007; 581:4139-47. [PMID: 17692849 DOI: 10.1016/j.febslet.2007.07.062] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2007] [Revised: 07/09/2007] [Accepted: 07/09/2007] [Indexed: 10/23/2022]
Abstract
Recombinant ATP sulfurylase (AcATPS1) and adenosine-5'-phosphosulfate reductase (AcAPR1) from Allium cepa have been used to determine if these enzymes form protein-protein complexes in vitro. Using a solid phase binding assay, AcAPR1 was shown to interact with AcATPS1. The AcAPR1 enzyme was also expressed in E. coli as the N-terminal reductase domain (AcAPR1-N) and the C-terminal glutaredoxin domain (AcAPR1-C), but neither of these truncated proteins interacted with AcATPS1. The solid-phase interactions were confirmed by immune-precipitation, where anti-AcATPS1 IgG precipitated the full-length AcAPR1 protein, but not AcAPR1-N and AcAPR1-C. Finally, using the ligand binding assay, full-length AcATPS1 has been shown to bind to membrane-localised full-length AcAPR1. The significance of an interaction between chloroplastidic ATPS and APR in A. cepa is evaluated with respect to the control of the reductive assimilation of sulfate.
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Affiliation(s)
- Mathew Cumming
- Institute of Molecular Biosciences, Massey University, Private Bag 11-222, Palmerston North, New Zealand
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Katz YS, Galili G, Amir R. Regulatory role of cystathionine-gamma-synthase and de novo synthesis of methionine in ethylene production during tomato fruit ripening. PLANT MOLECULAR BIOLOGY 2006; 61:255-68. [PMID: 16786305 DOI: 10.1007/s11103-006-0009-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2005] [Accepted: 01/05/2006] [Indexed: 05/09/2023]
Abstract
The essential amino acid methionine is a substrate for the synthesis of S-adenosyl-methionine (SAM), that donates its methyl group to numerous methylation reactions, and from which polyamines and ethylene are generated. To study the regulatory role of methionine synthesis in tomato fruit ripening, which requires a sharp increase in ethylene production, we cloned a cDNA encoding cystathionine gamma-synthase (CGS) from tomato and analysed its mRNA and protein levels during tomato fruit ripening. CGS mRNA and protein levels peaked at the "turning" stage and declined as the fruit ripened. Notably, the tomato CGS mRNA level in both leaves and fruit was negatively affected by methionine feeding, a regulation that Arabidopsis, but not potato CGS mRNA is subject to. A positive correlation was found between elevated ethylene production and increased CGS mRNA levels during the ethylene burst of the climacteric ripening of tomato fruit. In addition, wounding of pericarp from tomato fruit at the mature green stage stimulated both ethylene production and CGS mRNA level. Application of exogenous methionine to pericarp of mature green fruit increased ethylene evolution, suggesting that soluble methionine may be a rate limiting metabolite for ethylene synthesis. Moreover, treatment of mature green tomato fruit with the ethylene-releasing reagent Ethephon caused an induction of CGS mRNA level, indicating that CGS gene expression is regulated by ethylene. Taken together, these results imply that in addition to recycling of the methionine moieties via the Yang pathway, operating during synthesis of ethylene, de novo synthesis of methionine may be required when high rates of ethylene production are induced.
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Affiliation(s)
- Yael S Katz
- Plant Science Laboratory, Migal Galilee Technological Center, Kiryat Shmona, Israel
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Chen BCM, McManus MT. Expression of 1-aminocyclopropane-1-carboxylate (ACC) oxidase genes during the development of vegetative tissues in white clover (Trifolium repens L.) is regulated by ontological cues. PLANT MOLECULAR BIOLOGY 2006; 60:451-67. [PMID: 16514566 DOI: 10.1007/s11103-005-4813-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2005] [Accepted: 11/05/2005] [Indexed: 05/06/2023]
Abstract
Four 5' flanking sequences, comprising the 5'-UTR and upstream promoter region, have been isolated and cloned from the 1-aminocyclopropane-1-carboxylate (ACC) oxidase gene family of white clover (Trifolium repens L.), and designated TR-ACO1p, TR-ACO2p, TR-ACO3p and TR-ACO4p. Southern analysis confirmed that these sequences correspond to four distinct genes. The four corresponding genomic sequences have also been isolated and each shown to be comprised of four exons interspersed by three introns. The expression pattern, in vivo, directed by all four 5' flanking sequences during leaf development has been examined using GUS fusions and transformation into white clover. Here, the TR-ACO1 5' flanking sequence directs highest expression in the apical tissues, axillary buds, and leaf petiolules in younger tissues and then declines in the ageing tissues, while the TR-ACO2 5' flanking sequence directs expression in both younger, mature green and in ontologically ageing tissue. The TR-ACO3 and TR-ACO4 5' flanking sequences direct more expression in the ontological older tissues, including the axillary buds and leaf petiolules. The TR-ACO1 5' flanking sequence directed expression in the ground meristem and newly emerged leaf tissue at the apical bud of the stolon, but all four 5' flanking sequences directed expression in the ground meristem tissue of axillary buds, vascular tissue, pith and cortex of the internode and node, and the cortex and vascular tissue of the leaf petiolule, with the primacy of each promoter determined by the ontological age of the tissues. These data suggest that in vegetative tissue development of white clover, the primary cues for the transcriptional regulation of the ACO gene family are ontological in nature.
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Affiliation(s)
- Balance C-M Chen
- Institute of Molecular BioSciences, Massey University, Private Bag 11222, Palmerston North, New Zealand
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Gapper NE, Coupe SA, McKenzie MJ, Scott RW, Christey MC, Lill RE, McManus MT, Jameson PE. Senescence-associated down-regulation of 1-aminocyclopropane-1-carboxylate (ACC) oxidase delays harvest-induced senescence in broccoli. FUNCTIONAL PLANT BIOLOGY : FPB 2005; 32:891-901. [PMID: 32689185 DOI: 10.1071/fp05076] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2005] [Accepted: 06/08/2005] [Indexed: 06/11/2023]
Abstract
To gain an in-depth understanding of the role of ethylene in post harvest senescence, we used broccoli (Brassica oleracea var. italica) as our model species. The senescence-associated asparagine synthetase (AS) promoter from asparagus was used to drive the expression of an antisense 1-aminocyclopropane-1-carboxylate oxidase (ACO) cDNA from broccoli, BoACO2, to reduce ethylene production following harvest. Physiological analyses revealed that transgenic broccoli lines harbouring the antisense BoACO2 gene construct (designated as AS-asACO) displayed delayed senescence in both detached leaves and detached heads as measured by hue angle. Harvested floret tissue from these plants also showed a delayed loss of chlorophyll, lower protease activity and higher total protein content, and changes in transcript levels of senescence marker genes when compared with wild type and transgenic lines transformed with an empty T-DNA. Genes that were down-regulated included those coding for cysteine protease (BoCP5), metallothionein-like protein (BoMT1), hexokinase (BoHK1), invertase (BoINV1) and sucrose transporters (BoSUC1 and BoSUC2). Northern analysis for BoACO1 and BoACO2, ACO assays and western analysis, revealed reduced ACO transcript, enzyme activity and protein accumulation, as well as reduced ethylene production in the transgenic AS-asACO lines when compared with controls, confirming that a key enzyme regulating ethylene biosynthesis was reduced in these plants. This, together with the changes observed in gene expression, confirm a significant role for ethylene in regulating the events leading to senescence in broccoli following harvest.
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Affiliation(s)
- Nigel E Gapper
- New Zealand Institute for Crop & Food Research Limited, Food Industry Science Centre, Private Bag 11600, Palmerston North, New Zealand
| | - Simon A Coupe
- New Zealand Institute for Crop & Food Research Limited, Food Industry Science Centre, Private Bag 11600, Palmerston North, New Zealand
| | - Marian J McKenzie
- New Zealand Institute for Crop & Food Research Limited, Food Industry Science Centre, Private Bag 11600, Palmerston North, New Zealand
| | - Richard W Scott
- Institute of Molecular BioSciences, Massey University, Private Bag 11222, Palmerston North, New Zealand
| | - Mary C Christey
- New Zealand Institute for Crop & Food Research Limited, Private Bag 4704, Christchurch, New Zealand
| | - Ross E Lill
- New Zealand Institute for Crop & Food Research Limited, Food Industry Science Centre, Private Bag 11600, Palmerston North, New Zealand
| | - Michael T McManus
- Institute of Molecular BioSciences, Massey University, Private Bag 11222, Palmerston North, New Zealand
| | - Paula E Jameson
- Institute of Molecular BioSciences, Massey University, Private Bag 11222, Palmerston North, New Zealand
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McManus MT, Leung S, Lambert A, Scott RW, Pither-Joyce M, Chen B, McCallum J. Molecular and biochemical characterisation of a serine acetyltransferase of onion, Allium cepa (L.). PHYTOCHEMISTRY 2005; 66:1407-16. [PMID: 15949827 DOI: 10.1016/j.phytochem.2005.04.034] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2004] [Revised: 04/21/2005] [Accepted: 04/21/2005] [Indexed: 05/02/2023]
Abstract
We have previously cloned a cDNA, designated SAT1, corresponding to a gene coding for a serine acetyltransferase (SAT) from onion (Allium cepa L.). The SAT1 locus was mapped to chromosome 7 of onion using a single-stranded conformation polymorphism (SSCP) in the 3' UTR of the gene. Northern analysis has demonstrated that expression of the SAT1 gene is induced in leaf tissue in response to low S-supply. Phylogenetic analysis has placed SAT1 in a strongly supported group (100% bootstrap) that comprises sequences that have been characterised biochemically, including Allium tuberosum, Spinacea oleracea, Glycine max, Citrullus vulgaris, and SAT5 (AT5g56760) of Arabidopsis thaliana. This group can be divided further with the SAT1 of A. cepa sequence grouping strongly with the A. tuberosum sequence. Translation of SAT1 from onion generates a protein of 289 amino acids with a calculated molecular mass of 30,573 Da and pI of 6.52. The conserved G277 and H282 residues that have been identified as critical for L-cysteine inhibition are observed at G272 and H277. SAT1 has been cloned into the pGEX plasmid, expressed in E. coli and SAT activity of the recombinant enzyme has been measured as acetyl-CoA hydrolysis detected at 232 nm. A Km of 0.72 mM was determined for l-serine as substrate, a Km of 92 microM was calculated with acetyl-CoA as substrate, and an inhibition curve for L-cysteine generated an IC50 value of 3.1 microM. Antibodies raised against the recombinant SAT1 protein recognised a protein of ca. 33 kDa in whole leaf onion extracts. These properties of the SAT1 enzyme from onion are compared with other SAT enzymes characterised from closely related species.
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Affiliation(s)
- Michael T McManus
- Institute of Molecular BioSciences, Massey University, Private Bag 11222, Palmerston North, New Zealand.
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Young TE, Meeley RB, Gallie DR. ACC synthase expression regulates leaf performance and drought tolerance in maize. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2004; 40:813-25. [PMID: 15546363 DOI: 10.1111/j.1365-313x.2004.02255.x] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Ethylene regulates entry into several types of plant developmental cell death and senescence programs besides mediating plant responses to biotic and abiotic stress. The response of cereals to conditions of drought includes loss of leaf function and premature onset of senescence in older leaves. In this study, ACC synthase (ACS) mutants, affecting the first step in ethylene biosynthesis, were isolated in maize and their effect on leaf function examined. Loss of ZmACS6 expression resulted in delayed leaf senescence under normal growth conditions and inhibited drought-induced senescence. Zmacs6 leaves continued to be photosynthetically active under both conditions indicating that leaf function was maintained. The delayed senescence phenotype associated with loss of ZmACS6 expression was complemented by exogenous ACC. Surprisingly, elevated levels of foliar chlorophyll, Rubisco, and soluble protein as well as improved leaf performance was observed for all Zmasc6 leaves, including young and fully expanded leaves which were far from initiating senescence. These observations suggest that ethylene may serve to regulate leaf performance throughout its lifespan as well as to determine the onset of natural senescence and mediate drought-induced senescence.
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Affiliation(s)
- Todd E Young
- Department of Biochemistry, University of California, Riverside, CA 92521-0129, USA
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Yang CY, Chu FH, Wang YT, Chen YT, Yang SF, Shaw JF. Novel broccoli 1-aminocyclopropane-1-carboxylate oxidase gene (Bo-ACO3) associated with the late stage of postharvest floret senescence. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2003; 51:2569-2575. [PMID: 12696939 DOI: 10.1021/jf034007m] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A novel 1-aminocyclopropane-1-carboxylate (ACC) oxidase gene (Bo-ACO3) was first isolated from senescing broccoli florets by subtractive hybridization. The cDNA clone comprised a 963 bp open reading frame encoding a protein of 321 amino acids. The predicted molecular mass and pI were 36 kDa and 5.42, respectively. Bo-ACO3 shares 68% identity in the coding region with Bo-ACO1 (ACC Ox1) and Bo-ACO2 (ACC Ox2) and is quite divergent from the 3' untranslated regions. Bo-ACO3 transcript was accumulated to high levels only at the late stage of senescence after harvest. Southern blot hybridization using full-length cDNA as a probe suggested that the Bo-ACO3 gene is a single-copy gene in the broccoli genome. The deduced 321 amino acid sequence of Bo-ACO3 shares 70% identity with either Bo-ACO1 or Bo-ACO2. The BO-ACO3 gene was expressed in Escherichia coli as a 38 kDa active ACO enzyme. It was concluded that Bo-ACO3 is a senescence-associated gene involved in the late-phase senescence of postharvest broccoli.
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Affiliation(s)
- Chih-Yuan Yang
- Life Science Center, Hsing Wu College, No. 11-2 Fen-Liao Road, Lin-Kou, Taipei, Taiwan 11244
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Henderson J, Lyne L, Osborne DJ. Failed expression of an endo-beta-1,4-glucanhydrolase (cellulase) in a non-abscinding mutant of Lupinus angustifolius cv Danja. PHYTOCHEMISTRY 2001; 58:1025-1034. [PMID: 11730865 DOI: 10.1016/s0031-9422(01)00384-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Cellulase expressions in a normal shedding wild-type and a non-abscinding single gene mutant of Lupinus angustifolius have been studied during ethylene treatments of leaf abscission zone explants. Of the range of different glycohydrolases investigated only the abscission cell-specific beta-1,4-glucanhydrolase (cellulase) was not produced in the non-abscinding mutant. An endo-polygalacturonase was induced equally in both wild-type and mutant and other glycohydrolases were equally up-regulated. The abscission cell-specific cellulase induced at shedding of wild-type is antigenically similar to the Phaseolus vulgaris induced leaf abscission pI 9.5 cellulase but with a higher molecular mass (50 kD compared with 48 kD) and like the bean abscission-specific cellulase that of lupin is not glycosylated. Causes of the loss of function of cellulase expression in the non-shedding mutant are discussed.
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Affiliation(s)
- J Henderson
- Oxford Research Unit, Open University, Foxcombe Hall, Boars Hill, Oxford, OX1 5HR, UK
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