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Fu X, Lv CY, Zhang YY, Ai XZ, Bi HG. Comparative transcriptome analysis of grafting to improve chilling tolerance of cucumber. PROTOPLASMA 2023; 260:1349-1364. [PMID: 36949344 DOI: 10.1007/s00709-023-01854-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 03/13/2023] [Indexed: 06/18/2023]
Abstract
Grafting with pumpkin as rootstock could improve chilling tolerance of cucumber; however, the underlying mechanism of grafting-induced chilling tolerance remains unclear. Here, we analyzed the difference of physiological and transcriptional level between own-rooted (Cs/Cs) and hetero-grafted (Cs/Cm) cucumber seedlings under chilling stress. The results showed that grafting with pumpkin significantly alleviated the chilling injury as evidenced by slightly symptoms, lower contents of electrolyte leakage (EL), malondialdehyde (MDA), hydrogen peroxide (H2O2), and superoxide anion (O2-) and higher relative water content in Cs/Cm seedlings compared with Cs/Cs seedlings under chilling stress. RNA-seq data showed that grafting induced more DGEs at 8 °C/5 °C compared with 25 °C/18 °C. In accordance with the increase of the activities of antioxidant enzymes (SOD, POD, CAT, APX), grafting upregulated the expression of the regulated redox-related genes such as GST, SOD, and APX. Moreover, grafting increased the expression of genes participated in central carbon metabolism to promote the conversion and decomposition of sugar, which provided more energy for the growth of Cs/Cm seedlings under chilling stress. In addition, grafting regulated the genes involved in the intracellular signal transduction pathways such as calcium signal (CAML, CML, and CDPK) and inositol phospholipid signal (PLC), as well as changed the gene expression of plant hormone signal transduction pathways (ARF, GAI, ABF, and PYR/PYL). These results provide a physiological and transcriptional basis for the molecular mechanism of grafting-induced chilling tolerance of cucumber seedlings.
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Affiliation(s)
- Xin Fu
- State Key Laboratory of Crop Biology, Key Laboratory of Crop Biology and Genetic Improvement of Horticultural Crops in Huanghuai Region, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, 271018, Shandong, China
| | - Chun-Yu Lv
- State Key Laboratory of Crop Biology, Key Laboratory of Crop Biology and Genetic Improvement of Horticultural Crops in Huanghuai Region, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, 271018, Shandong, China
| | - Yan-Yan Zhang
- State Key Laboratory of Crop Biology, Key Laboratory of Crop Biology and Genetic Improvement of Horticultural Crops in Huanghuai Region, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, 271018, Shandong, China
- Tai'an Academy of Agricultural Sciences, Tai'an, 271000, China
| | - Xi-Zhen Ai
- State Key Laboratory of Crop Biology, Key Laboratory of Crop Biology and Genetic Improvement of Horticultural Crops in Huanghuai Region, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, 271018, Shandong, China
| | - Huan-Gai Bi
- State Key Laboratory of Crop Biology, Key Laboratory of Crop Biology and Genetic Improvement of Horticultural Crops in Huanghuai Region, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, 271018, Shandong, China.
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Cannon AE, Marston EJ, Kiszonas AM, Hauvermale AL, See DR. Late-maturity α-amylase (LMA): exploring the underlying mechanisms and end-use quality effects in wheat. PLANTA 2021; 255:2. [PMID: 34837530 PMCID: PMC8627422 DOI: 10.1007/s00425-021-03749-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 10/03/2021] [Indexed: 06/13/2023]
Abstract
MAIN CONCLUSION A comprehensive understanding of LMA from the underlying molecular aspects to the end-use quality effects will greatly benefit the global wheat industry and those whose livelihoods depend upon it. Late-maturity α-amylase (LMA) leads to the expression and protein accumulation of high pI α-amylases during late grain development. This α-amylase is maintained through harvest and leads to an unacceptable low falling number (FN), the wheat industry's standard measure for predicting end-use quality. Unfortunately, low FN leads to significant financial losses for growers. As a result, wheat researchers are working to understand and eliminate LMA from wheat breeding programs, with research aims that include unraveling the genetic, biochemical, and physiological mechanisms that lead to LMA expression. In addition, cereal chemists and quality scientists are working to determine if and how LMA-affected grain impacts end-use quality. This review is a comprehensive overview of studies focused on LMA and includes open questions and future directions.
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Affiliation(s)
- Ashley E. Cannon
- Wheat Health, Genetics, and Quality Research Unit, USDA Agricultural Research Service, Pullman, WA USA
- Department of Crop and Soil Sciences, Washington State University, Pullman, WA USA
| | - Elliott J. Marston
- Department of Plant Pathology, Washington State University, Pullman, WA USA
| | - Alecia M. Kiszonas
- Department of Crop and Soil Sciences, Washington State University, Pullman, WA USA
| | - Amber L. Hauvermale
- Department of Crop and Soil Sciences, Washington State University, Pullman, WA USA
| | - Deven R. See
- Wheat Health, Genetics, and Quality Research Unit, USDA Agricultural Research Service, Pullman, WA USA
- Department of Plant Pathology, Washington State University, Pullman, WA USA
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Integrated Analysis of the Transcriptome and Metabolome Revealed Candidate Genes Involved in GA 3-Induced Dormancy Release in Leymus chinensis Seeds. Int J Mol Sci 2021; 22:ijms22084161. [PMID: 33920519 PMCID: PMC8074249 DOI: 10.3390/ijms22084161] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 04/06/2021] [Accepted: 04/13/2021] [Indexed: 11/16/2022] Open
Abstract
Leymus chinensis is a perennial forage grass that has good palatability, high yield and high feed value, but seed dormancy is a major problem limiting the widespread cultivation of L. chinensis. Here, we performed transcriptomic and metabolomic analysis of hulled and de-hulled seeds of L. chinensis treated with or without GA3 to investigate the changes in gene and metabolites associated with dormancy release induced by GA3. The germination test revealed that the optimum concentration of GA3 for disruption of L. chinensis seed dormancy was 577 μM. A total of 4327 and 11,919 differentially expressed genes (DEGs) and 871 and 650 differentially abundant metabolites were identified in de-hulled and hulled seeds treated with GA3, respectively, compared with seeds soaked in sterile water. Most of the DEGs were associated with starch and sucrose metabolism, protein processing in the endoplasmic reticulum, endocytosis and ribosomes. Furthermore, isoquinoline alkaloid biosynthesis, tyrosine metabolism, starch and sucrose metabolism, arginine and proline metabolism, and amino sugar and nucleotide sugar metabolism were significantly enriched pathways. Integrative analysis of the transcriptomic and metabolomic data revealed that starch and sucrose metabolism is one of the most important pathways that may play a key role in providing carbon skeletons and energy supply for the transition of L. chinensis seeds from a dormant state to germination by suppressing the expression of Cel61a, egID, cel1, tpsA, SPAC2E11.16c and TPP2, enhancing the expression of AMY1.1, AMY1.2, AMY1.6 and GLIP5, and inhibiting the synthesis of cellobiose, cellodextrin, and trehalose while promoting the hydrolysis of sucrose, starch, cellobiose, cellodextrin, and trehalose to glucose. This study identified several key genes and provided new insights into the molecular mechanism of seed dormancy release induced by GA3 in L. chinensis. These putative genes will be valuable resources for improving the seed germination rate in future breeding studies.
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Smailov B, Alybayev S, Smekenov I, Mursalimov A, Saparbaev M, Sarbassov D, Bissenbaev A. Wheat Germination Is Dependent on Plant Target of Rapamycin Signaling. Front Cell Dev Biol 2020; 8:606685. [PMID: 33330509 PMCID: PMC7719826 DOI: 10.3389/fcell.2020.606685] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 10/21/2020] [Indexed: 12/21/2022] Open
Abstract
Germination is a process of seed sprouting that facilitates embryo growth. The breakdown of reserved starch in the endosperm into simple sugars is essential for seed germination and subsequent seedling growth. At the early stage of germination, gibberellic acid (GA) activates transcription factor GAMYB to promote de novo synthesis of isoforms of α-amylase in the aleurone layer and scutellar epithelium of the embryo. Here, we demonstrate that wheat germination is regulated by plant target of rapamycin (TOR) signaling. TOR is a central component of the essential-nutrient–dependent pathway controlling cell growth in all eukaryotes. It is known that rapamycin, a highly specific allosteric inhibitor of TOR, is effective in yeast and animal cells but ineffective in most of higher plants likely owing to structural differences in ubiquitous rapamycin receptor FKBP12. The action of rapamycin on wheat growth has not been studied. Our data show that rapamycin inhibits germination of wheat seeds and of their isolated embryos in a dose-dependent manner. The involvement of Triticum aestivum TOR (TaTOR) in wheat germination was consistent with the suppression of wheat embryo growth by specific inhibitors of the TOR kinase: pp242 or torin1. Rapamycin or torin1 interfered with GA function in germination because of a potent inhibitory effect on α-amylase and GAMYB gene expression. The TOR inhibitors selectively targeted the GA-dependent gene expression, whereas expression of the abscisic acid-dependent ABI5 gene was not affected by either rapamycin or torin1. To determine whether the TaTOR kinase activation takes place during wheat germination, we examined phosphorylation of a ribosomal protein, T. aestivum S6 kinase 1 (TaS6K1; a substrate of TOR). The phosphorylation of serine 467 (S467) in a hydrophobic motif on TaS6K1 was induced in a process of germination triggered by GA. Moreover, the germination-induced phosphorylation of TaS6K1 on S467 was dependent on TaTOR and was inhibited by rapamycin or torin1. Besides, a gibberellin biosynthesis inhibitor (paclobutrazol; PBZ) blocked not only α-amylase gene expression but also TaS6K1 phosphorylation in wheat embryos. Thus, a hormonal action of GA turns on the synthesis of α-amylase in wheat germination via activation of the TaTOR–S6K1 signaling pathway.
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Affiliation(s)
- Bauyrzhan Smailov
- Department of Molecular Biology and Genetics, Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, Kazakhstan.,Scientific Research Institute of Biology and Biotechnology Problems, Al-Farabi Kazakh National University, Almaty, Kazakhstan
| | - Sanzhar Alybayev
- Department of Molecular Biology and Genetics, Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, Kazakhstan.,Scientific Research Institute of Biology and Biotechnology Problems, Al-Farabi Kazakh National University, Almaty, Kazakhstan
| | - Izat Smekenov
- Department of Molecular Biology and Genetics, Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, Kazakhstan.,Scientific Research Institute of Biology and Biotechnology Problems, Al-Farabi Kazakh National University, Almaty, Kazakhstan
| | - Aibek Mursalimov
- Department of Molecular Biology and Genetics, Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, Kazakhstan.,Scientific Research Institute of Biology and Biotechnology Problems, Al-Farabi Kazakh National University, Almaty, Kazakhstan
| | - Murat Saparbaev
- Department of Molecular Biology and Genetics, Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, Kazakhstan.,Groupe «Mechanisms of DNA Repair and Carcinogenesis», Equipe Labellisée LIGUE 2016, CNRS UMR 9019, Université Paris-Sud, Gustave Roussy Cancer Campus, Villejuif, France
| | - Dos Sarbassov
- Department of Biology, Nazarbayev University, Nur-Sultan, Kazakhstan
| | - Amangeldy Bissenbaev
- Department of Molecular Biology and Genetics, Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, Kazakhstan.,Scientific Research Institute of Biology and Biotechnology Problems, Al-Farabi Kazakh National University, Almaty, Kazakhstan
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5
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Lan J, Lin Q, Zhou C, Ren Y, Liu X, Miao R, Jing R, Mou C, Nguyen T, Zhu X, Wang Q, Zhang X, Guo X, Liu S, Jiang L, Wan J. Small grain and semi-dwarf 3, a WRKY transcription factor, negatively regulates plant height and grain size by stabilizing SLR1 expression in rice. PLANT MOLECULAR BIOLOGY 2020; 104:429-450. [PMID: 32808190 DOI: 10.1007/s11103-020-01049-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Accepted: 08/06/2020] [Indexed: 05/29/2023]
Abstract
OsWRKY36 represses plant height and grain size by inhibiting gibberellin signaling. Plant height and grain size are important agronomic traits affecting yield in cereals, including rice. Gibberellins (GAs) are plant hormones that promote plant growth and developmental processions such as stem elongation and grain size. WRKYs are transcription factors that regulate stress tolerance and plant development including height and grain size. However, the relationship between GA signaling and WRKY genes is still poorly understood. Here, we characterized a small grain and semi-dwarf 3 (sgsd3) mutant in rice cv. Hwayoung (WT). A T-DNA insertion in the 5'-UTR of OsWRKY36 induced overexpression of OsWRKY36 in the sgsd3 mutant, likely leading to the mutant phenotype. This was confirmed by the finding that overexpression of OsWRKY36 caused a similar small grain and semi-dwarf phenotype to the sgsd3 mutant whereas knock down and knock out caused larger grain phenotypes. The sgsd3 mutant was also hyposensitive to GA and accumulated higher mRNA and protein levels of SLR1 (a GA signaling DELLA-like inhibitor) compared with the WT. Further assays showed that OsWRKY36 enhanced SLR1 transcription by directly binding to its promoter. In addition, we found that OsWRKY36 can protect SLR1 from GA-mediated degradation. We thus identified a new GA signaling repressor OsWRKY36 that represses GA signaling through stabilizing the expression of SLR1.
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Affiliation(s)
- Jie Lan
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China
| | - Qibing Lin
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Chunlei Zhou
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yakun Ren
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China
| | - Xi Liu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China
| | - Rong Miao
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China
| | - Ruonan Jing
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China
| | - Changling Mou
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China
| | - Thanhliem Nguyen
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China
- Department of Biology and Agricultural Engineering, Quynhon University, Quynhon, Binhdinh, 590000, Vietnam
| | - Xingjie Zhu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China
| | - Qian Wang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China
| | - Xin Zhang
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Xiuping Guo
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Shijia Liu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China
| | - Ling Jiang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China.
| | - Jianmin Wan
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China.
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
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6
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Guo X, Li J, Zhang L, Zhang Z, He P, Wang W, Wang M, Wang A, Zhu J. Heterotrimeric G-protein α subunit (LeGPA1) confers cold stress tolerance to processing tomato plants (Lycopersicon esculentum Mill). BMC PLANT BIOLOGY 2020; 20:394. [PMID: 32847511 PMCID: PMC7448358 DOI: 10.1186/s12870-020-02615-w] [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: 04/10/2020] [Accepted: 08/19/2020] [Indexed: 06/02/2023]
Abstract
BACKGROUND Tomatoes (Lycopersicon esculentum Mill) are key foods, and their molecular biology and evolution have been well described. Tomato plants originated in the tropics and, thus, are cold sensitive. RESULTS Here, we generated LeGPA1 overexpressing and RNA-interference (RNAi) transgenic tomato plants, which we then used to investigate the function of LeGPA1 in response to cold stress. Functional LeGPA1 was detected at the plasma membrane, and endogenous LeGPA1 was highly expressed in the roots and leaves. Cold treatment positively induced the expression of LeGPA1. Overexpression of LeGPA1 conferred tolerance to cold conditions and regulated the expression of genes related to the INDUCER OF CBF EXPRESSION-C-REPEAT-BINDING FACTOR (ICE-CBF) pathway in tomato plants. In the LeGPA1-overexpressing transgenic plants, the superoxide dismutase, peroxidase, and catalase activities and soluble sugar and proline contents were increased, and the production of reactive oxygen species and membrane lipid peroxidation decreased under cold stress. CONCLUSIONS Our findings suggest that improvements in antioxidant systems can help plants cope with the oxidative damage caused by cold stress, thereby stabilizing cell membrane structures and increasing the rate of photosynthesis. The data presented here provide evidence for the key role of LeGPA1 in mediating cold signal transduction in plant cells. These findings extend our knowledge of the roles of G-proteins in plants and help to clarify the mechanisms through which growth and development are regulated in processing tomato plants.
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Affiliation(s)
- Xinyong Guo
- College of Life Science, Shihezi University, Shihezi, 832000, China
| | - Juju Li
- College of Life Science, Shihezi University, Shihezi, 832000, China
| | - Li Zhang
- College of Life Science, Shihezi University, Shihezi, 832000, China
| | - Zhanwen Zhang
- College of Life Science, Shihezi University, Shihezi, 832000, China
| | - Ping He
- College of Life Science, Shihezi University, Shihezi, 832000, China
| | - Wenwen Wang
- College of Life Science, Shihezi University, Shihezi, 832000, China
| | - Mei Wang
- College of Life Science, Shihezi University, Shihezi, 832000, China
| | - Aiying Wang
- College of Life Science, Shihezi University, Shihezi, 832000, China
| | - Jianbo Zhu
- College of Life Science, Shihezi University, Shihezi, 832000, China.
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Mark C, Zór K, Heiskanen A, Dufva M, Emnéus J, Finnie C. Monitoring intra- and extracellular redox capacity of intact barley aleurone layers responding to phytohormones. Anal Biochem 2016; 515:1-8. [PMID: 27641112 DOI: 10.1016/j.ab.2016.09.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 09/12/2016] [Accepted: 09/14/2016] [Indexed: 11/29/2022]
Abstract
Redox regulation is important for numerous processes in plant cells including abiotic stress, pathogen defence, tissue development, seed germination and programmed cell death. However, there are few methods allowing redox homeostasis to be addressed in whole plant cells, providing insight into the intact in vivo environment. An electrochemical redox assay that applies the menadione-ferricyanide double mediator is used to assess changes in the intracellular and extracellular redox environment in living aleurone layers of barley (Hordeum vulgare cv. Himalaya) grains, which respond to the phytohormones gibberellic acid and abscisic acid. Gibberellic acid is shown to elicit a mobilisation of electrons as detected by an increase in the reducing capacity of the aleurone layers. By taking advantage of the membrane-permeable menadione/menadiol redox pair to probe the membrane-impermeable ferricyanide/ferrocyanide redox pair, the mobilisation of electrons was dissected into an intracellular and an extracellular, plasma membrane-associated component. The intracellular and extracellular increases in reducing capacity were both suppressed when the aleurone layers were incubated with abscisic acid. By probing redox levels in intact plant tissue, the method provides a complementary approach to assays of reactive oxygen species and redox-related enzyme activities in tissue extracts.
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Affiliation(s)
- Christina Mark
- Agricultural and Environmental Proteomics, Department of Systems Biology, Technical University of Denmark, DK-2800 Kgs.Lyngby, Denmark
| | - Kinga Zór
- Bioanalytics, Department of Micro- and Nanotechnology, Technical University of Denmark, DK-2800 Kgs.Lyngby, Denmark
| | - Arto Heiskanen
- Bioanalytics, Department of Micro- and Nanotechnology, Technical University of Denmark, DK-2800 Kgs.Lyngby, Denmark
| | - Martin Dufva
- Fluidic Array Systems and Technology, Department of Micro- and Nanotechnology, Technical University of Denmark, DK-2800 Kgs.Lyngby, Denmark
| | - Jenny Emnéus
- Bioanalytics, Department of Micro- and Nanotechnology, Technical University of Denmark, DK-2800 Kgs.Lyngby, Denmark
| | - Christine Finnie
- Agricultural and Environmental Proteomics, Department of Systems Biology, Technical University of Denmark, DK-2800 Kgs.Lyngby, Denmark; Carlsberg Research Laboratory, J.C. Jacobsens Gade 4, DK-1799 Copenhagen V, Denmark.
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8
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Yamaguchi I, Nakajima M, Park SH. Trails to the gibberellin receptor, GIBBERELLIN INSENSITIVE DWARF1. Biosci Biotechnol Biochem 2016; 80:1029-36. [PMID: 26927225 DOI: 10.1080/09168451.2016.1148575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The researches on the identification of gibberellin receptor are reviewed from the early attempts in 1960s to the identification of GIBBERELLIN INSENSITIVE DWARF1 (GID1) as the receptor in 2005. Unpublished data of the gibberellin-binding protein in the seedlings of adzuki bean (Vigna angularis) are also included, suggesting that the active principle of the gibberellin-binding protein was a GID1 homolog.
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Affiliation(s)
- Isomaro Yamaguchi
- a Department of Applied Biological Chemistry , The University of Tokyo , Tokyo , Japan
| | - Masatoshi Nakajima
- a Department of Applied Biological Chemistry , The University of Tokyo , Tokyo , Japan
| | - Seung-Hyun Park
- a Department of Applied Biological Chemistry , The University of Tokyo , Tokyo , Japan
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9
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Hedden P, Sponsel V. A Century of Gibberellin Research. JOURNAL OF PLANT GROWTH REGULATION 2015; 34:740-60. [PMID: 26523085 PMCID: PMC4622167 DOI: 10.1007/s00344-015-9546-1] [Citation(s) in RCA: 267] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 09/25/2015] [Indexed: 05/17/2023]
Abstract
Gibberellin research has its origins in Japan in the 19th century, when a disease of rice was shown to be due to a fungal infection. The symptoms of the disease including overgrowth of the seedling and sterility were later shown to be due to secretions of the fungus Gibberella fujikuroi (now reclassified as Fusarium fujikuroi), from which the name gibberellin was derived for the active component. The profound effect of gibberellins on plant growth and development, particularly growth recovery in dwarf mutants and induction of bolting and flowering in some rosette species, prompted speculation that these fungal metabolites were endogenous plant growth regulators and this was confirmed by chemical characterisation in the late 1950s. Gibberellins are now known to be present in vascular plants, and some fungal and bacterial species. The biosynthesis of gibberellins in plants and the fungus has been largely resolved in terms of the pathways, enzymes, genes and their regulation. The proposal that gibberellins act in plants by removing growth limitation was confirmed by the demonstration that they induce the degradation of the growth-inhibiting DELLA proteins. The mechanism by which this is achieved was clarified by the identification of the gibberellin receptor from rice in 2005. Current research on gibberellin action is focussed particularly on the function of DELLA proteins as regulators of gene expression. This review traces the history of gibberellin research with emphasis on the early discoveries that enabled the more recent advances in this field.
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Affiliation(s)
- Peter Hedden
- />Rothamsted Research, West Common, Harpenden, AL5 2JQ Hertfordshire UK
| | - Valerie Sponsel
- />Department of Biology, The University of Texas at San Antonio, San Antonio, TX 78249 USA
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10
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Wu M, Wang F, Zhang C, Xie Y, Han B, Huang J, Shen W. Heme oxygenase-1 is involved in nitric oxide- and cGMP-induced α-Amy2/54 gene expression in GA-treated wheat aleurone layers. PLANT MOLECULAR BIOLOGY 2013; 81:27-40. [PMID: 23090695 DOI: 10.1007/s11103-012-9979-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Accepted: 10/15/2012] [Indexed: 05/04/2023]
Abstract
Here, α-Amy2/54 gene expression was used as a molecular probe to investigate the interrelationship among nitric oxide (NO), cyclic GMP (cGMP), and heme oxygenase-1 (HO-1) in GA-treated wheat aleurone layers. The inducible expressions of α-Amy2/54 and α-amylase activity were respectively amplified by two NO-releasing compounds, sodium nitroprusside (SNP) and spermine NONOate, in a GA-dependent fashion. Similar responses were observed when an inducer of HO-1, hemin-or one of its catalytic products, carbon monoxide (CO) in aqueous solution-was respectively added. The SNP-induced responses, mimicked by 8-bromoguanosine 3',5'-cyclic monophosphate (8-Br-cGMP), a cGMP derivative, were NO-dependent. This conclusion was supported by the fact that endogenous NO overproduction was rapidly induced by SNP, and thereafter induction of α-Amy2/54 gene expression and increased α-amylase activity were sensitive to the NO scavenger. We further observed that the above induction triggered by SNP and 8-Br-cGMP was partially prevented by zinc protoporphyrin IX (ZnPPIX), an inhibitor of HO-1. These blocking effects were clearly reversed by CO, confirming that the above response was HO-1-specific. Further analyses showed that both SNP and 8-Br-cGMP rapidly up-regulated HO-1 gene expression and increased HO activity, and SNP responses were sensitive to cPTIO and the guanylate cyclase inhibitor 6-anilino-5,8-quinolinedione (LY83583). Molecular evidence confirmed that GA-induced GAMYB and ABA-triggered PKABA1 transcripts were up-regulated or down-regulated by SNP, 8-Br-cGMP or CO cotreated with GA. Contrasting changes were observed when cPTIO, LY83583, or ZnPPIX was added. Together, our results suggested that HO-1 is involved in NO- and cGMP-induced α-Amy2/54 gene expression in GA-treated aleurone layers.
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Affiliation(s)
- Mingzhu Wu
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
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11
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Zhang H, Wang M, Wang W, Li D, Huang Q, Wang Y, Zheng X, Zhang Z. Silencing of G proteins uncovers diversified plant responses when challenged by three elicitors in Nicotiana benthamiana. PLANT, CELL & ENVIRONMENT 2012; 35:72-85. [PMID: 21895695 DOI: 10.1111/j.1365-3040.2011.02417.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Signalling through heterotrimeric G protein composed of α-, β- and γ-subunits is essential in numerous physiological processes. Here we show that this prototypical G protein complex acts mechanistically by controlling elicitor sensitivity towards hypersensitive response (HR) and stomatal closure in Nicotiana benthamiana. Gα-, Gβ1-, and Gβ2-silenced plants were generated using virus-induced gene silencing. All silenced plants were treated with Xanthomonas oryzae harpin, Magnaporthe oryzae Nep1 and Phytophthora boehmeriae boehmerin, respectively. HR was dramatically impaired in Gα- and Gβ2-silenced plants treated with harpin, indicating that harpin-, rather than Nep1- or boehmerin-triggered HR, is Gα- and Gβ2-dependent. Moreover, all Gα-, Gβ1- and Gβ2-silenced plants significantly impaired elicitor-induced stomatal closure, elicitor-promoted nitric oxide (NO) production and active oxygen species accumulation in guard cells. To our knowledge, this is the first report of Gα and Gβ subunits involvement in stomatal closure in response to elicitors. Furthermore, silencing of Gα, Gβ1 and Gβ2 has an effect on the transcription of plant defence-related genes when challenged by three elicitors. In conclusion, silencing of G protein subunits results in many interesting plant cell responses, revealing that plant immunity systems employ both conserved and distinct G protein pathways to sense elicitors from distinct phytopathogens formed during plant-microbe evolution.
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Affiliation(s)
- Huajian Zhang
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
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12
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Izawa Y, Minami M, Ohki S, Iwasaki Y. Expression profile of the α subunit of the heterotrimeric G protein in rice. PLANT SIGNALING & BEHAVIOR 2010; 5:845-847. [PMID: 21206728 PMCID: PMC3014535 DOI: 10.4161/psb.5.7.11824] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Accepted: 03/14/2010] [Indexed: 05/29/2023]
Abstract
Previous studies on the activity of the rice Gα promoter using a β-Glucuronidase (GUS) reporter construct indicated that Gα expression was highest in developing organs and changed in a developmental stage-dependent manner. In this paper, GUS activity derived from the rice Gα promoter was analyzed in seeds and developing leaves. In seeds, GUS activity was detected in the aleurone layer, embryo, endosperm and scutellar epithelium. In developing leaves, the activity was detected in the mesophyll tissues, phloem and xylem of the leaf sheath and in the mesophyll tissue of the leaf blade. The activity in the aleurone layer and scutellar epithelium suggests that the Gα subunit may be involved in gibberellin signaling. The activity in the mesophyll tissues of the leaf blade suggests that the Gα subunit may be related to the intensity of disease resistance. The pattern of the activity in the developing leaf also indicates that the expression of Gα follows a developmental profile at the tissue level.
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Affiliation(s)
- Yuki Izawa
- Department of Bioscience, Fukui Prefectural University; Eiheiji-cho, Yoshida-gun, Fukui, Japan
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13
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WANG WT, ZHANG JW, WANG D, TAO SH, JI YL, WU B. Relation between Light Qualities and Accumulation of Steroidal Glycoalkaloids as Well as Signal Molecule in Cell in Potato Tubers. ACTA AGRONOMICA SINICA 2010. [DOI: 10.3724/sp.j.1006.2010.00629] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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14
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Mitsunaga SI, Kobayashi M, Fukui S, Fukuoka K, Kawakami O, Yamaguchi J, Ohshima M, Mitsui T. Alpha-amylase production is induced by sulfuric acid in rice aleurone cells. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2007; 45:922-925. [PMID: 17988885 DOI: 10.1016/j.plaphy.2007.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2006] [Indexed: 05/25/2023]
Abstract
The hydrolytic enzyme alpha-amylase (EC 3.2.1.1) is produced mainly in aleurone cells of germinating cereals, and the phytohormone gibberellin (GA) is essential for its induction. However, in rice (Oryza sativa L.), sulfuric acid (H(2)SO(4)) induces alpha-amylase production in aleurone tissue even in the absence of GA. Here, the pre-treatment of rice aleurone cells with H(2)SO(4) and incubation in water induced alpha-amylase activity, as if the cells had been incubated in GA solution.
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Affiliation(s)
- Shin-ichiro Mitsunaga
- Faculty of Education, Joetsu University of Education, 1 Yamayashiki, Joetsu, Niigata, Japan.
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15
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Vivar-Evans S, Barradas VL, Sánchez-Coronado ME, Gamboa de Buen A, Orozco-Segovia A. Ecophysiology of seed germination of wild Dahlia coccinea (Asteraceae) in a spatially heterogeneous fire-prone habitat. ACTA OECOLOGICA-INTERNATIONAL JOURNAL OF ECOLOGY 2006. [DOI: 10.1016/j.actao.2005.10.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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16
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Khan MMK, Jan A, Karibe H, Komatsu S. Identification of phosphoproteins regulated by gibberellin in rice leaf sheath. PLANT MOLECULAR BIOLOGY 2005; 58:27-40. [PMID: 16028114 DOI: 10.1007/s11103-005-4013-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2005] [Accepted: 03/17/2005] [Indexed: 05/03/2023]
Abstract
To identify the gibberellin (GA) signaling components involved in rice leaf sheath elongation process, protein phosphorylation changed by GA3 was analyzed. The protein kinase activities in rice leaf sheath were assessed in an in-gel kinase assay using SDS-polyacrylamide gel containing histone III-S as a substrate. The activity of a putative 54-kDa calcium dependent protein kinase (CDPK) in cytosolic fraction in rice leaf sheath increased significantly by GA3. Further, phosphorylation status of the proteins changed by GA3 in rice leaf sheath were detected by in vitro protein phosphorylation followed by two-dimensional polyacrylamide gel electrophoresis and the phosphoproteins were identified by mass spectrometry. Sixty phosphoproteins was detected after in vitro protein phosphorylation and the phosphorylation of 7 proteins was enhanced by GA3 treatment. The addition of GA3 treated cytosolic fraction of leaf sheath further increased the phosphorylation of 4 proteins, glyoxalase-I, cytoplasmic malate dehydrogenase, glyceraldehydes-3-phosphate dehydrogenase and another unknown protein. The protein kinase inhibitor, staurosporine inhibited the phosphorylation of these proteins in vitro. Other hormones, particularly, indole acetic acid, 6-benzylaminopurine and abscisic acid did not change the phosphorylation status of these proteins. The identified proteins did not show any change by GA3 treatment at transcription level. The abundance of glyoxalase-I and cytoplasmic malate dehydrogenase remained unchanged by GA3 treatment as detected on 2D-gel by silver staining, unlike for glyceraldehydes-3-phosphate dehydrogenase. Results suggest that the phosphoproteins, glyoxalase-I and cytoplasmic malate dehydrogenase in rice leaf sheath could be important signaling components of GA3, downstream to 54-kDa CDPK.
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Affiliation(s)
- Md Monowar Karim Khan
- Department of Molecular Genetics, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, 305-8602, Tsukuba, Japan
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17
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Peskan-Berghöfer T, Neuwirth J, Kusnetsov V, Oelmüller R. Suppression of heterotrimeric G-protein beta-subunit affects anther shape, pollen development and inflorescence architecture in tobacco. PLANTA 2005; 220:737-46. [PMID: 15747144 DOI: 10.1007/s00425-004-1393-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2004] [Accepted: 08/06/2004] [Indexed: 05/24/2023]
Abstract
The role of the heterotrimeric G-protein beta-subunit in plant development was studied in transgenic tobacco (Nicotiana tabacum L.) plants with reduced beta-subunit levels due to the antisense expression of the beta-subunit mRNA. The antisense plants had aberrant anther shape and produced non-germinating pollen. The anthers were sporadically transformed to petals, whereas other floral organs were not affected. The pollen grains were smaller than the wild-type pollen and had abnormal cell walls. The architecture of mature antisense plants was altered. The plants had long branched panicles and short stems. These data suggest that the beta-subunit of the plant heterotrimeric G-proteins is involved in the regulation of the reproductive phase of the tobacco life cycle, particularly in stamen development and pollen maturation.
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Affiliation(s)
- Tatjana Peskan-Berghöfer
- Institute of General Botany and Plant Physiology, Friedrich-Schiller-University Jena, Dornburgerstr. 159, 07743 Jena, Germany
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18
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Oki K, Fujisawa Y, Kato H, Iwasaki Y. Study of the Constitutively Active Form of the α Subunit of Rice Heterotrimeric G Proteins. ACTA ACUST UNITED AC 2005; 46:381-6. [PMID: 15695461 DOI: 10.1093/pcp/pci036] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
We used site-directed mutagenesis to engineer two constitutively active forms of the alpha subunit of a rice heterotrimeric G protein. The recombinant proteins produced from these novel cDNAs had GTP-binding activity but no GTPase activity. A chimeric gene for a constitutively active form of the alpha subunit was introduced into the rice mutant d1, which is defective for the alpha-subunit gene. All the transformants essentially showed a wild-type phenotype compared with normal cultivars, although seed sizes were substantially increased and internode lengths also showed some increase.
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Affiliation(s)
- Katsuyuki Oki
- Fukui Prefectural University, Faculty of Bioscience, Kenjyojima, Matsuoka-cho, Yoshida-gun, Fukui, 910-1195 Japan
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19
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Abstract
Gibberellins (GAs) are a family of plant hormones controlling many aspects of plant growth and development including stem elongation, germination, and the transition from vegetative growth to flowering. Cloning of the genes encoding GA biosynthetic and inactivating enzymes has led to numerous insights into the developmental regulation of GA hormone accumulation that is subject to both positive and negative feedback regulation. Genetic and biochemical analysis of GA-signaling genes has revealed that posttranslational regulation of DELLA protein accumulation is a key control point in GA response. The highly conserved DELLA proteins are a family of negative regulators of GA signaling that appear subject to GA-stimulated degradation through the ubiquitin-26S proteasome pathway. This review discusses the regulation of GA hormone accumulation and signaling in the context of its role in plant growth and development.
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Affiliation(s)
- Stephen G Thomas
- IACR Rothamsted Research, CPI Division, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom
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20
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Thomas SG, Sun TP. Update on gibberellin signaling. A tale of the tall and the short. PLANT PHYSIOLOGY 2004; 135:668-76. [PMID: 15208413 PMCID: PMC514103 DOI: 10.1104/pp.104.040279] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2004] [Revised: 02/18/2004] [Accepted: 02/20/2004] [Indexed: 05/18/2023]
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21
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Kolla VA, Suhita D, Raghavendra AS. Marked changes in volume of mesophyll protoplasts of pea (Pisum sativum) on exposure to growth hormones. JOURNAL OF PLANT PHYSIOLOGY 2004; 161:557-62. [PMID: 15202712 DOI: 10.1078/0176-1617-01076] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The present study reports quick and significant changes induced by plant hormones in the volume of mesophyll protoplasts of pea (Pisum sativum). Four plant hormones: gibberellic acid (GA3), indole 3-acetic acid (IAA), abscisic acid (ABA)(+/-) and methyl jasmonate (MJ), caused marked changes in the volume of mesophyll protoplasts. GA3 and IAA increased the volume of the protoplasts (up to 90%) whereas the ABA and MJ decreased (by about 40%) the volume. Aquaporins or water channels appear to play an important role in swelling/shrinkage of the protoplasts as indicated by the suppression of volume changes by HgCl2 and reversal by mercaptoethanol. The possible role of secondary messengers in volume changes induced by GA3 was investigated by using selected pharmacological reagents. The GA3 induced swelling was restricted by GDP-beta-S (G-protein antagonist), U73122 (phospholipase C inhibitor), and TFP (calmodulin antagonist), but was not affected by 1-butanol (phospholipase D inhibitor), GTP-gamma-S (G-protein agonist), or verapamil (calcium channel blocker). The results suggest that the mesophyll protoplasts can be a simple and useful system for further studies on volume changes in plant tissues.
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Affiliation(s)
- Venkat Apparao Kolla
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad 500 046, India
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22
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Miles GP, Samuel MA, Jones AM, Ellis BE. Mastoparan rapidly activates plant MAP kinase signaling independent of heterotrimeric G proteins. PLANT PHYSIOLOGY 2004; 134:1332-6. [PMID: 15084727 PMCID: PMC419810 DOI: 10.1104/pp.103.037275] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2003] [Revised: 12/30/2003] [Accepted: 12/30/2003] [Indexed: 05/19/2023]
Affiliation(s)
- Godfrey P Miles
- Biotechnology Laboratory, Agricultural Sciences, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
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23
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Zhang ZL, Xie Z, Zou X, Casaretto J, Ho THD, Shen QJ. A rice WRKY gene encodes a transcriptional repressor of the gibberellin signaling pathway in aleurone cells. PLANT PHYSIOLOGY 2004; 134:1500-13. [PMID: 15047897 PMCID: PMC419826 DOI: 10.1104/pp.103.034967] [Citation(s) in RCA: 219] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2003] [Revised: 11/21/2003] [Accepted: 01/13/2004] [Indexed: 05/18/2023]
Abstract
The molecular mechanism by which GA regulates plant growth and development has been a subject of active research. Analyses of the rice (Oryza sativa) genomic sequences identified 77 WRKY genes, among which OsWRKY71 is highly expressed in aleurone cells. Transient expression of OsWRKY71 by particle bombardment specifically represses GA-induced Amy32b alpha-amylase promoter but not abscisic acid-induced HVA22 or HVA1 promoter activity in aleurone cells. Moreover, OsWRKY71 blocks the activation of the Amy32b promoter by the GA-inducible transcriptional activator OsGAMYB. Consistent with its role as a transcriptional repressor, OsWRKY71 is localized to nuclei of aleurone cells and binds specifically to functionally defined TGAC-containing W boxes of the Amy32b promoter in vitro. Mutation of the two W boxes prevents the binding of OsWRKY71 to the mutated promoter, and releases the suppression of the OsGAMYB-activated Amy32b expression by OsWRKY71, suggesting that OsWRKY71 blocks GA signaling by functionally interfering with OsGAMYB. Exogenous GA treatment decreases the steady-state mRNA level of OsWRKY71 and destabilizes the GFP:OsWRKY71 fusion protein. These findings suggest that OsWRKY71 encodes a transcriptional repressor of GA signaling in aleurone cells.
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Affiliation(s)
- Zhong-Lin Zhang
- Department of Biological Sciences, University of Nevada, 4505 Maryland Parkway, Las Vegas, Nevada 89154, USA
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24
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Day RB, Tanabe S, Koshioka M, Mitsui T, Itoh H, Ueguchi-Tanaka M, Matsuoka M, Kaku H, Shibuya N, Minami E. Two rice GRAS family genes responsive to N -acetylchitooligosaccharide elicitor are induced by phytoactive gibberellins: evidence for cross-talk between elicitor and gibberellin signaling in rice cells. PLANT MOLECULAR BIOLOGY 2004; 54:261-272. [PMID: 15159627 DOI: 10.1023/b:plan.0000028792.72343.ee] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In this study, we present data showing that two members of the GRAS family of genes from rice, CIGR1 and CIGR2 (chitin-inducible gibberellin-responsive), inducible by the potent elicitor N -acetylchitooligosaccharide (GN), are rapidly induced by exogenous gibberellins. The pattern of mRNA accumulation was dependent on the dose and biological activity of the gibberellins, suggesting that the induction of the genes by gibberellin is mediated by a biological receptor capable of specific recognition and signal transduction upon perception of the phytoactive compounds. Further pharmacological analysis revealed that the CIGR1 and CIGR2 mRNA accumulation by treatment with gibberellin is dependent upon protein phosphorylation/dephosphorylation events. In rice calli derived from slender rice 1, a constitutive gibberellin-responsive mutant, or d1, a mutant deficient in the alpha -subunit of the heterotrimeric G-protein, CIGR1 and CIGR2 were induced by a GN elicitor, yet not by gibberellin. Neither gibberellin nor GN showed related activities in defense or development, respectively. These results strongly suggested that the signal transduction cascade from gibberellin is independent of that from GN, and further implied that CIGR1 and CIGR2 have dual, distinct roles in defense and development.
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Affiliation(s)
- R Bradley Day
- Department of Biochemistry, National Institute of Agrobiological Sciences, 2-1-2, Kannondai, Tsukuba 305-8602, Japan
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25
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Abstract
The hormone gibberellin (GA) plays an important role in modulating diverse processes throughout plant development. In recent years, significant progress has been made in the identification of upstream GA signaling components and trans- and cis-acting factors that regulate downstream GA-responsive genes in higher plants. GA appears to derepress its signaling pathway by inducing proteolysis of GA signaling repressors (the DELLA proteins). Recent evidence indicates that the DELLA proteins are targeted for degradation by an E3 ubiquitin ligase SCF complex through the ubiquitin-26S proteasome pathway.
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Affiliation(s)
- Tai-Ping Sun
- Department of Biology, Duke University, Durham, North Carolina 27708, USA.
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26
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Hossain MS, Koba T, Harada K. Cloning and characterization of two full-length cDNAs, TaGA1 and TaGA2, encoding G-protein alpha subunits expressed differentially in wheat genome. Genes Genet Syst 2003; 78:127-38. [PMID: 12773813 DOI: 10.1266/ggs.78.127] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
In the present study, we identified and characterized two cDNAs, named TaGA1 and TaGA2, encoding alpha subunits of heterotrimeric G proteins synthesized from one-week-old seedling mRNAs of common wheat cv. S615 using RACE PCR and RT-PCR methods. The clone TaGA1 contained an open reading frame that encoded a protein consisting of 383 amino acid residues with a molecular mass of 51.3 kDa, whereas the clone TaGA2 contained an open reading frame encoding 390 amino acids with a molecular mass of 52.5 kDa. At the amino acid level, both cDNAs (TaGA1 and TaGA2) showed 70-96% and 30-40% homologies to plant and animal G-protein alpha (G alpha) subunits, respectively, and 97.7% homology to each other. The regions essential for binding to GTP were conserved among all G alpha subunits in higher plants and mammals examined. However, the C-terminal amino acid sequences of TaGA1 and TaGA2 were similar to those of cereal G alpha subunits (rice and barley) but were different from the analogous sequences of mammalian G alpha subunits as well as from those of the leguminous and Solanaeceous G alpha subunits. Southern analysis revealed that the hexaploid wheat genome contained three major copies of G alpha subunit gene with a few less homologous copies. The analysis of the expression for G alpha subunit genes in wheat showed that both TaGA1 and TaGA2 mRNAs were abundant in one-week-old seedlings, immature seeds harvested one-week after anthesis, young spikes and internodes, indicating constitutive expression patterns in all of the organs tested. Especially, young spikes and internodes exhibited increased levels of mRNA accumulation, suggesting that G alpha subunit gene is highly expressed in actively elongating and fast growing tissues. Moreover, both TaGA1 and TaGA2 showed genome-specific expressions in wheat and may participate in the light-regulated growth and development of the seedlings.
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Affiliation(s)
- Md Shakhawat Hossain
- Laboratory of Genetics and Plant Breeding, Faculty of Horticulture, Graduate School of Science and Technology, Chiba University, Japan
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27
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Ullah H, Chen JG, Temple B, Boyes DC, Alonso JM, Davis KR, Ecker JR, Jones AM. The beta-subunit of the Arabidopsis G protein negatively regulates auxin-induced cell division and affects multiple developmental processes. THE PLANT CELL 2003; 15:393-409. [PMID: 12566580 PMCID: PMC141209 DOI: 10.1105/tpc.006148] [Citation(s) in RCA: 269] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2002] [Accepted: 10/30/2002] [Indexed: 05/18/2023]
Abstract
Plant cells respond to low concentrations of auxin by cell expansion, and at a slightly higher concentration, these cells divide. Previous work revealed that null mutants of the alpha-subunit of a putative heterotrimeric G protein (GPA1) have reduced cell division. Here, we show that this prototypical G protein complex acts mechanistically by controlling auxin sensitivity toward cell division. Loss-of-function G protein mutants have altered auxin-mediated cell division throughout development, especially during the auxin-induced formation of lateral and adventitious root primordia. Ectopic expression of the wild-type Galpha-subunit phenocopies the Gbeta mutants (auxin hypersensitivity), probably by sequestering the Gbetagamma-subunits, whereas overexpression of Gbeta reduces auxin sensitivity and a constitutively active (Q222L) mutant Galpha behaves like the wild type. These data are consistent with a model in which Gbetagamma acts as a negative regulator of auxin-induced cell division. Accordingly, basal repression of approximately one-third of the identified auxin-regulated genes (47 of 150 upregulated genes among 8300 quantitated) is lost in the Gbeta transcript-null mutant. Included among these are genes that encode proteins proposed to control cell division in root primordia formation as well as several novel genes. These results suggest that although auxin-regulated cell division is not coupled directly by a G protein, the Gbeta-subunit attenuates this auxin pathway upstream of the control of mRNA steady state levels.
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Affiliation(s)
- Hemayet Ullah
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3280, USA
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28
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Fu X, Richards DE, Ait-Ali T, Hynes LW, Ougham H, Peng J, Harberd NP. Gibberellin-mediated proteasome-dependent degradation of the barley DELLA protein SLN1 repressor. THE PLANT CELL 2002; 14:3191-200. [PMID: 12468736 PMCID: PMC151211 DOI: 10.1105/tpc.006197] [Citation(s) in RCA: 174] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2002] [Accepted: 09/13/2002] [Indexed: 05/18/2023]
Abstract
DELLA proteins are nuclear repressors of plant gibberellin (GA) responses. Here, we investigate the properties of SLN1, a DELLA protein from barley that is destabilized by GA treatment. Using specific inhibitors of proteasome function, we show that proteasome-mediated protein degradation is necessary for GA-mediated destabilization of SLN1. We also show that GA responses, such as the aleurone alpha-amylase response and seedling leaf extension growth, require proteasome-dependent GA-mediated SLN1 destabilization. In further experiments with protein kinase and protein phosphatase inhibitors, we identify two additional signaling steps that are necessary for GA response and for GA-mediated destabilization of SLN1. Thus, GA signaling involves protein phosphorylation and dephosphorylation steps and promotes the derepression of GA responses via proteasome-dependent destabilization of DELLA repressors.
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Affiliation(s)
- Xiangdong Fu
- John Innes Centre, Colney Lane, Norwich NR4 7UJ, United Kingdom
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29
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Suharsono U, Fujisawa Y, Kawasaki T, Iwasaki Y, Satoh H, Shimamoto K. The heterotrimeric G protein alpha subunit acts upstream of the small GTPase Rac in disease resistance of rice. Proc Natl Acad Sci U S A 2002; 99:13307-12. [PMID: 12237405 PMCID: PMC130629 DOI: 10.1073/pnas.192244099] [Citation(s) in RCA: 224] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2002] [Indexed: 11/18/2022] Open
Abstract
We used rice dwarf1 (d1) mutants lacking a single-copy Galpha gene and addressed Galpha's role in disease resistance. d1 mutants exhibited a highly reduced hypersensitive response to infection by an avirulent race of rice blast. Activation of PR gene expression in the leaves of the mutants infected with rice blast was delayed for 24 h relative to the wild type. H(2)O(2) production and PR gene expression induced by sphingolipid elicitors (SE) were strongly suppressed in d1 cell cultures. Expression of the constitutively active OsRac1, a small GTPase Rac of rice, in d1 mutants restored SE-dependent defense signaling and resistance to rice blast. Galpha mRNA was induced by an avirulent race of rice blast and SE application on the leaf. These results indicated the role of Galpha in R gene-mediated disease resistance of rice. We have proposed a model for the defense signaling of rice in which the heterotrimeric G protein functions upstream of the small GTPase OsRac1 in the early steps of signaling.
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Affiliation(s)
- Utut Suharsono
- Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma 630-0101, Japan
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30
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Zentella R, Yamauchi D, Ho THD. Molecular dissection of the gibberellin/abscisic acid signaling pathways by transiently expressed RNA interference in barley aleurone cells. THE PLANT CELL 2002; 14:2289-301. [PMID: 12215521 PMCID: PMC150771 DOI: 10.1105/tpc.003376] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2002] [Accepted: 05/25/2002] [Indexed: 05/18/2023]
Abstract
The interaction between two phytohormones, gibberellins (GA) and abscisic acid (ABA), is an important factor regulating the developmental transition from seed dormancy to germination. In cereal aleurone tissue, GA induces and ABA suppresses the expression of alpha-amylases that are essential for the utilization of starch stored in the endosperm. In this work, the signaling pathways mediated by these hormones were investigated in the aleurone cells of barley seeds using double-stranded RNA interference (RNAi) technology. In this tissue, double-stranded RNA molecules generated from the transient expression of DNA templates caused a sequence-specific suppression of the target genes. We demonstrate that the transcription factor, GAMyb, is not only sufficient but also necessary for the GA induction of alpha-amylase. Another regulatory protein, SLN1, is shown to be a repressor of GA action, and the use of RNAi technology to inhibit the synthesis of SLN1 led to derepression of alpha-amylase even in the absence of GA. However, this effect still was suppressed by ABA. Although the ABA-induced Ser/Thr protein kinase, PKABA1, is known to suppress GA-induced alpha-amylase expression, PKABA1 RNAi did not hamper the inhibitory effect of ABA on the expression of alpha-amylase, indicating that a PKABA1-independent signaling pathway also may exist. We suggest that the generation of specific RNAi in a transient expression approach is a useful technique for elucidating the role of regulatory molecules in biological systems in which conventional mutational studies cannot be performed easily.
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Affiliation(s)
- Rodolfo Zentella
- Plant Biology Program, Department of Biology, Washington University, St. Louis, Missouri 63130, USA
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31
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Nakayama A, Park S, Zheng-Jun X, Nakajima M, Yamaguchi I. Immunohistochemistry of active gibberellins and gibberellin-inducible alpha-amylase in developing seeds of morning glory. PLANT PHYSIOLOGY 2002; 129:1045-53. [PMID: 12114559 PMCID: PMC166499 DOI: 10.1104/pp.010921] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2001] [Revised: 12/03/2001] [Accepted: 02/22/2002] [Indexed: 05/18/2023]
Abstract
Gibberellins (GAs) in developing seeds of morning glory (Pharbitis nil) were quantified and localized by immunostaining. The starch grains began to be digested after the GA contents had increased and reached a plateau. Immunohistochemical staining with the antigibberellin A(1)-methyl ester-antiserum, which has high affinity to biologically active GAs, showed that GA(1) and/or GA(3) were localized around starch grains in the integument of developing young seeds, suggesting the participation of GA-inducible alpha-amylase in this digestion. We isolated an alpha-amylase cDNA (PnAmy1) that was expressed in the immature seeds, and using an antibody raised against recombinant protein, it was shown that PnAmy1 was expressed in the immature seeds. GA responsiveness of PnAmy1 was shown by treating the young fruits 9 d after anthesis with GA(3). RNA-blot and immunoblot analyses showed that PnAmy1 emerged soon after the rapid increase of GA(1/3). An immunohistochemical analysis of PnAmy1 showed that it, like the seed GA(1/3), was also localized around starch grains in the integument of developing young seeds. The localization of GA(1/3) in the integument coincident with the expression of PnAmy1 suggests that both function as part of a process to release sugars for translocation or for the further development of the seeds.
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Affiliation(s)
- Akira Nakayama
- Department of Applied Biological Chemistry, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
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Ullah H, Chen JG, Wang S, Jones AM. Role of a heterotrimeric G protein in regulation of Arabidopsis seed germination. PLANT PHYSIOLOGY 2002; 129:897-907. [PMID: 12068128 PMCID: PMC161710 DOI: 10.1104/pp.005017] [Citation(s) in RCA: 154] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2002] [Revised: 03/15/2002] [Accepted: 04/02/2002] [Indexed: 05/18/2023]
Abstract
Seed germination is regulated by many signals. We investigated the possible involvement of a heterotrimeric G protein complex in this signal regulation. Seeds that carry a protein null mutation in the gene encoding the alpha subunit of the G protein in Arabidopsis (GPA1) are 100-fold less responsive to gibberellic acid (GA), have increased sensitivity to high levels of Glc, and have a near-wild-type germination response to abscisic acid and ethylene, indicating that GPA1 does not directly couple these signals in germination control. Seeds ectopically expressing GPA1 are at least a million-fold more responsive to GA, yet still require GA for germination. We conclude that the GPA1 indirectly operates on the GA pathway to control germination by potentiation. We propose that this potentiation is directly mediated by brassinosteroids (BR) because the BR response and synthesis mutants, bri1-5 and det2-1, respectively, share the same GA sensitivity as gpa1 seeds. Furthermore, gpa1 seeds are completely insensitive to brassinolide rescue of germination when the level of GA in seeds is reduced. A lack of BR responsiveness is also apparent in gpa1 roots and hypocotyls suggesting that BR signal transduction is likely coupled by a heterotrimeric G protein at various points in plant development.
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Affiliation(s)
- Hemayet Ullah
- Department of Agronomy, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
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33
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Swain SM, Tseng TS, Thornton TM, Gopalraj M, Olszewski NE. SPINDLY is a nuclear-localized repressor of gibberellin signal transduction expressed throughout the plant. PLANT PHYSIOLOGY 2002; 129:605-15. [PMID: 12068105 PMCID: PMC161687 DOI: 10.1104/pp.020002] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2002] [Revised: 02/08/2002] [Accepted: 02/26/2002] [Indexed: 05/18/2023]
Abstract
SPY (SPINDLY) encodes a putative O-linked N-acetyl-glucosamine transferase that is genetically defined as a negatively acting component of the gibberellin (GA) signal transduction pathway. Analysis of Arabidopsis plants containing a SPY::GUS reporter gene reveals that SPY is expressed throughout the life of the plant and in most plant organs examined. In addition to being expressed in all organs where phenotypes due to spy mutations have been reported, SPY::GUS is expressed in the root. Examination of the roots of wild-type, spy, and gai plants revealed phenotypes indicating that SPY and GAI play a role in root development. A second SPY::GUS reporter gene lacking part of the SPY promoter was inactive, suggesting that sequences in the first exon and/or intron are required for detectable expression. Using both subcellular fractionation and visualization of a SPY-green fluorescent protein fusion protein that is able to rescue the spy mutant phenotype, the majority of SPY protein was shown to be present in the nucleus. This result is consistent with the nuclear localization of other components of the GA response pathway and suggests that SPY's role as a negative regulator of GA signaling involves interaction with other nuclear proteins and/or O-N-acetyl-glucosamine modification of these proteins.
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Affiliation(s)
- Stephen M Swain
- Department of Plant Biology and Plant Molecular Genetics Institute, University of Minnesota, St. Paul, MN 55108, USA.
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Gubler F, Chandler PM, White RG, Llewellyn DJ, Jacobsen JV. Gibberellin signaling in barley aleurone cells. Control of SLN1 and GAMYB expression. PLANT PHYSIOLOGY 2002; 129:191-200. [PMID: 12011350 PMCID: PMC155883 DOI: 10.1104/pp.010918] [Citation(s) in RCA: 163] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2001] [Revised: 11/15/2001] [Accepted: 01/20/2002] [Indexed: 05/18/2023]
Abstract
We have previously identified GAMYB, a gibberellin (GA)-regulated transcriptional activator of alpha-amylase gene expression, in aleurone cells of barley (Hordeum vulgare). To examine the regulation of GAMYB expression, we describe the use of nuclear run-on experiments to show that GA causes a 2-fold increase in the rate of GAMYB transcription and that the effect of GA can be blocked by abscisic acid (ABA). To identify GA-signaling components that regulate GAMYB expression, we examined the role of SLN1, a negative regulator of GA signaling in barley. SLN1, which is the product of the Sln1 (Slender1) locus, is necessary for repression of GAMYB in barley aleurone cells. The activity of SLN1 in aleurone cells is regulated posttranslationally. SLN1 protein levels decline rapidly in response to GA before any increase in GAMYB levels. Green fluorescent protein-SLN1 fusion protein was targeted to the nucleus of aleurone protoplasts and disappeared in response to GA. Evidence from a dominant dwarf mutant at Sln1, and from the gse1 mutant (that affects GA "sensitivity"), indicates that GA acts by regulating SLN1 degradation and not translation. Mutation of the DELLA region of SLN1 results in increased protein stability in GA-treated layers, indicating that the DELLA region plays an important role in GA-induced degradation of SLN1. Unlike GA, ABA had no effect on SLN1 stability, confirming that ABA acts downstream of SLN1 to block GA signaling.
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Affiliation(s)
- Frank Gubler
- Commonwealth Scientific and Industrial Research Organization, Plant Industry, G.P.O. Box 1600, Canberra, Australian Capital Territory 2601, Australia.
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Olszewski N, Sun TP, Gubler F. Gibberellin signaling: biosynthesis, catabolism, and response pathways. THE PLANT CELL 2002; 14 Suppl:S61-S80. [PMID: 12045270 DOI: 10.1105/tpc.010476.gas] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Affiliation(s)
- Neil Olszewski
- Department of Plant Biology and Plant Molecular Genetics Institute, University of Minnesota, St. Paul, MN 55108-1095, USA.
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36
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Olszewski N, Sun TP, Gubler F. Gibberellin signaling: biosynthesis, catabolism, and response pathways. THE PLANT CELL 2002; 14 Suppl:S61-80. [PMID: 12045270 PMCID: PMC151248 DOI: 10.1105/tpc.010476] [Citation(s) in RCA: 578] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2001] [Accepted: 02/11/2002] [Indexed: 05/17/2023]
Affiliation(s)
- Neil Olszewski
- Department of Plant Biology and Plant Molecular Genetics Institute, University of Minnesota, St. Paul, MN 55108-1095, USA.
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37
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Olszewski N, Sun TP, Gubler F. Gibberellin signaling: biosynthesis, catabolism, and response pathways. THE PLANT CELL 2002. [PMID: 12045270 DOI: 10.2307/3871750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Affiliation(s)
- Neil Olszewski
- Department of Plant Biology and Plant Molecular Genetics Institute, University of Minnesota, St. Paul, MN 55108-1095, USA.
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38
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Assmann SM. Heterotrimeric and unconventional GTP binding proteins in plant cell signaling. THE PLANT CELL 2002; 14 Suppl:S355-73. [PMID: 12045288 PMCID: PMC151266 DOI: 10.1105/tpc.001792] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2002] [Accepted: 03/24/2002] [Indexed: 05/17/2023]
Affiliation(s)
- Sarah M Assmann
- Biology Department, Pennsylvania State University, 208 Mueller Laboratory, University Park, PA 16802, USA.
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39
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Assmann SM. Heterotrimeric and unconventional GTP binding proteins in plant cell signaling. THE PLANT CELL 2002; 14 Suppl:S355-S373. [PMID: 12045288 DOI: 10.1105/tpc.001792.s356] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Affiliation(s)
- Sarah M Assmann
- Biology Department, Pennsylvania State University, 208 Mueller Laboratory, University Park, PA 16802, USA.
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40
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Abstract
4,5-Diaminofluorescein, a fluorescence indicator for NO, was applied to detect the release of NO from plant cells. NO production was increased within 3 min when plant cell cultures (Arabidopsis, parsley, and tobacco) were treated by cytokinin and was dose-dependent and signal-specific in that other plant hormones and inactive cytokinin analog were not effective in stimulating of NO release. The response was quenched by addition of 2-(aminoethyl)-2-thiopseudourea, an inhibitor of the animal NO synthase, and by addition of an NO scavenger, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-1-oxy-3-oxide. These results imply that NO may act in cytokinin signal transduction.
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Affiliation(s)
- N N Tun
- Institut f. Zierpflanzenbau, Baumschule u. Pflanzenzüchtung, Abt. Spez. Ertragsphysiologie, Universität Hannover, Herrenhäuser Str. 2, D-30419, Hannover, Germany
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41
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Gocal GF, Sheldon CC, Gubler F, Moritz T, Bagnall DJ, MacMillan CP, Li SF, Parish RW, Dennis ES, Weigel D, King RW. GAMYB-like genes, flowering, and gibberellin signaling in Arabidopsis. PLANT PHYSIOLOGY 2001; 127:1682-1693. [PMID: 11743113 DOI: 10.1104/pp.127.4.1682] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We have identified three Arabidopsis genes with GAMYB-like activity, AtMYB33, AtMYB65, and AtMYB101, which can substitute for barley (Hordeum vulgare) GAMYB in transactivating the barley alpha-amylase promoter. We have investigated the relationships between gibberellins (GAs), these GAMYB-like genes, and petiole elongation and flowering of Arabidopsis. Within 1 to 2 d of transferring plants from short- to long-day photoperiods, growth rate and erectness of petioles increased, and there were morphological changes at the shoot apex associated with the transition to flowering. These responses were accompanied by accumulation of GAs in the petioles (GA(1) by 11-fold and GA(4) by 3-fold), and an increase in expression of AtMYB33 at the shoot apex. Inhibition of GA biosynthesis using paclobutrazol blocked the petiole elongation induced by long days. Causality was suggested by the finding that, with GA treatment, plants flowered in short days, AtMYB33 expression increased at the shoot apex, and the petioles elongated and grew erect. That AtMYB33 may mediate a GA signaling role in flowering was supported by its ability to bind to a specific 8-bp sequence in the promoter of the floral meristem-identity gene, LEAFY, this same sequence being important in the GA response of the LEAFY promoter. One or more of these AtMYB genes may also play a role in the root tip during germination and, later, in stem tissue. These findings extend our earlier studies of GA signaling in the Gramineae to include a dicot species, Arabidopsis, and indicate that GAMYB-like genes may mediate GA signaling in growth and flowering responses.
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Affiliation(s)
- G F Gocal
- Commonwealth Scientific and Industrial Research Organization, Plant Industry, G.P.O. Box 1600, Canberra, Australian Capital Territory 2601, Australia
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42
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Gocal GF, Sheldon CC, Gubler F, Moritz T, Bagnall DJ, MacMillan CP, Li SF, Parish RW, Dennis ES, Weigel D, King RW. GAMYB-like genes, flowering, and gibberellin signaling in Arabidopsis. PLANT PHYSIOLOGY 2001; 127:1682-1693. [PMID: 11743113 DOI: 10.1104/pp.010442] [Citation(s) in RCA: 184] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We have identified three Arabidopsis genes with GAMYB-like activity, AtMYB33, AtMYB65, and AtMYB101, which can substitute for barley (Hordeum vulgare) GAMYB in transactivating the barley alpha-amylase promoter. We have investigated the relationships between gibberellins (GAs), these GAMYB-like genes, and petiole elongation and flowering of Arabidopsis. Within 1 to 2 d of transferring plants from short- to long-day photoperiods, growth rate and erectness of petioles increased, and there were morphological changes at the shoot apex associated with the transition to flowering. These responses were accompanied by accumulation of GAs in the petioles (GA(1) by 11-fold and GA(4) by 3-fold), and an increase in expression of AtMYB33 at the shoot apex. Inhibition of GA biosynthesis using paclobutrazol blocked the petiole elongation induced by long days. Causality was suggested by the finding that, with GA treatment, plants flowered in short days, AtMYB33 expression increased at the shoot apex, and the petioles elongated and grew erect. That AtMYB33 may mediate a GA signaling role in flowering was supported by its ability to bind to a specific 8-bp sequence in the promoter of the floral meristem-identity gene, LEAFY, this same sequence being important in the GA response of the LEAFY promoter. One or more of these AtMYB genes may also play a role in the root tip during germination and, later, in stem tissue. These findings extend our earlier studies of GA signaling in the Gramineae to include a dicot species, Arabidopsis, and indicate that GAMYB-like genes may mediate GA signaling in growth and flowering responses.
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Affiliation(s)
- G F Gocal
- Commonwealth Scientific and Industrial Research Organization, Plant Industry, G.P.O. Box 1600, Canberra, Australian Capital Territory 2601, Australia
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Lease KA, Wen J, Li J, Doke JT, Liscum E, Walker JC. A mutant Arabidopsis heterotrimeric G-protein beta subunit affects leaf, flower, and fruit development. THE PLANT CELL 2001; 13:2631-41. [PMID: 11752377 PMCID: PMC139478 DOI: 10.1105/tpc.010315] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2001] [Accepted: 09/16/2001] [Indexed: 05/20/2023]
Abstract
A genetic screen was performed to find new mutants with an erecta (er) phenotype and to identify genes that may function with ER, a receptor-like kinase. These mutants were named elk (for erecta-like) and were placed into five complementation groups. We positionally cloned ELK4 and determined that it encodes AGB1, a putative heterotrimeric G-protein beta subunit. Therefore, elk4 was renamed agb1. agb1-1 plants express similar fruit phenotypes, as seen in er plants, but differ from er in that the stem is only slightly shorter than that in the wild type, the pedicel is slightly longer than that in the wild type, and the leaves are rounder than those in er mutants. Molecular analysis of agb1-1 indicates that it is likely a null allele. AGB1 mRNA is expressed in all tissues tested but is highest in the silique. Analysis of agb1-1 er double mutants suggests that AGB1 may function in an ER developmental pathway regulating silique width but that it functions in parallel pathways affecting silique length as well as leaf and stem development. The finding that AGB1 is involved in the control of organ shape suggests that heterotrimeric G-protein signaling is a developmental regulator in Arabidopsis.
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Affiliation(s)
- K A Lease
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, Missouri 65211, USA
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44
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Lease KA, Wen J, Li J, Doke JT, Liscum E, Walker JC. A mutant Arabidopsis heterotrimeric G-protein beta subunit affects leaf, flower, and fruit development. THE PLANT CELL 2001; 13:2631-2641. [PMID: 11752377 DOI: 10.1105/tpc.13.12.2631] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
A genetic screen was performed to find new mutants with an erecta (er) phenotype and to identify genes that may function with ER, a receptor-like kinase. These mutants were named elk (for erecta-like) and were placed into five complementation groups. We positionally cloned ELK4 and determined that it encodes AGB1, a putative heterotrimeric G-protein beta subunit. Therefore, elk4 was renamed agb1. agb1-1 plants express similar fruit phenotypes, as seen in er plants, but differ from er in that the stem is only slightly shorter than that in the wild type, the pedicel is slightly longer than that in the wild type, and the leaves are rounder than those in er mutants. Molecular analysis of agb1-1 indicates that it is likely a null allele. AGB1 mRNA is expressed in all tissues tested but is highest in the silique. Analysis of agb1-1 er double mutants suggests that AGB1 may function in an ER developmental pathway regulating silique width but that it functions in parallel pathways affecting silique length as well as leaf and stem development. The finding that AGB1 is involved in the control of organ shape suggests that heterotrimeric G-protein signaling is a developmental regulator in Arabidopsis.
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Affiliation(s)
- K A Lease
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, Missouri 65211, USA
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45
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Abstract
Biochemical studies suggest that G proteins mediate a variety of signaling processes in plants, yet Arabidopsis has only one gene, GPA1, for a canonical G protein alpha subunit. Recent studies indicate that the GPA1 protein is involved in a number of very different cellular processes.
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Affiliation(s)
- H Ma
- Department of Biology and the Life Sciences Consortium, 504 Wartik Laboratory, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
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46
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Fujisawa Y, Kato H, Iwasaki Y. Structure and function of heterotrimeric G proteins in plants. PLANT & CELL PHYSIOLOGY 2001; 42:789-94. [PMID: 11522903 DOI: 10.1093/pcp/pce111] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Heterotrimeric G proteins are mediators that transmit the external signals via receptor molecules to effector molecules. The G proteins consist of three different subunits: alpha, beta, and gamma subunits. The cDNAs or genes for all the alpha, beta, and gamma subunits have been isolated from many plant species, which has contributed to great progress in the study of the structure and function of the G proteins in plants. In addition, rice plants lacking the alpha subunit were generated by the antisense method and a rice mutant, Daikoku d1, was found to have mutation in the alpha-subunit gene. Both plants show abnormal morphology such as dwarfism, dark green leaf, and small round seed. The findings revealed that the G proteins are functional molecules regulating some body plans in plants. There is evidence that the plant G proteins participate at least in signaling of gibberellin at low concentrations. In this review, we summarize the currently known information on the structure of plant heterotrimeric G proteins and discuss the possible functions of the G proteins in plants.
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Affiliation(s)
- Y Fujisawa
- Department of Bioscience, Fukui Prefectural University, 4-1-1 Kenjyojima, Matsuoka-cho, Yoshida-gun, Fukui, 910-1195 Japan
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47
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Swain SM, Tseng TS, Olszewski NE. Altered expression of SPINDLY affects gibberellin response and plant development. PLANT PHYSIOLOGY 2001; 126:1174-85. [PMID: 11457967 PMCID: PMC116473 DOI: 10.1104/pp.126.3.1174] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2000] [Revised: 01/24/2001] [Accepted: 03/12/2001] [Indexed: 05/19/2023]
Abstract
Gibberellins (GAs) are plant hormones with diverse roles in plant growth and development. SPINDLY (SPY) is one of several genes identified in Arabidopsis that are involved in GA response and it is thought to encode an O-GlcNAc transferase. Genetic analysis suggests that SPY negatively regulates GA response. To test the hypothesis that SPY acts specifically as a negatively acting component of GA signal transduction, spy mutants and plants containing a 35S:SPY construct have been examined. A detailed investigation of the spy mutant phenotype suggests that SPY may play a role in plant development beyond its role in GA signaling. Consistent with this suggestion, the analysis of spy er plants suggests that the ERECTA (ER) gene, which has not been implicated as having a role in GA signaling, appears to enhance the non-GA spy mutant phenotypes. Arabidopsis plants containing a 35S:SPY construct possess reduced GA response at seed germination, but also possess phenotypes consistent with increased GA response, although not identical to spy mutants, during later vegetative and reproductive development. Based on these results, the hypothesis that SPY is specific for GA signaling is rejected. Instead, it is proposed that SPY is a negative regulator of GA response that has additional roles in plant development.
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Affiliation(s)
- S M Swain
- Department of Plant Biology and Plant Molecular Genetics Institute, University of Minnesota, St. Paul, Minnesota 55108, USA.
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48
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Okamoto H, Matsui M, Deng XW. Overexpression of the heterotrimeric G-protein alpha-subunit enhances phytochrome-mediated inhibition of hypocotyl elongation in Arabidopsis. THE PLANT CELL 2001. [PMID: 11449056 DOI: 10.2307/3871391] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Plant heterotrimeric G-proteins have been implicated in a number of signaling processes. However, most of these studies are based on biochemical or pharmacological approaches. To examine the role of heterotrimeric G-proteins in plant development, we generated transgenic Arabidopsis expressing the Galpha subunit of the heterotrimeric G-protein under the control of a glucocorticoid-inducible promoter. With the conditional overexpression of either the wild type or a constitutively active version of Arabidopsis Galpha, transgenic seedlings exhibited a hypersensitive response to light. This enhanced light sensitivity was more exaggerated in a relatively lower intensity of light and was observed in white light as well as far-red, red, and blue light conditions. The enhanced responses in far-red and red light required functional phytochrome A and phytochrome B, respectively. Furthermore, the response to far-red light depended on functional FHY1 but not on FIN219 and FHY3. This dependence on FHY1 indicates that the Arabidopsis Galpha protein may act only on a discrete branch of the phytochrome A signaling pathway. Thus, our results support the involvement of a heterotrimeric G-protein in the light regulation of Arabidopsis seedling development.
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Affiliation(s)
- H Okamoto
- Department of Molecular, Cellular, and Developmental Biology, Yale University, 165 Prospect Street, New Haven, CT 06520-8104, USA
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49
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Okamoto H, Matsui M, Deng XW. Overexpression of the heterotrimeric G-protein alpha-subunit enhances phytochrome-mediated inhibition of hypocotyl elongation in Arabidopsis. THE PLANT CELL 2001; 13:1639-52. [PMID: 11449056 PMCID: PMC139542 DOI: 10.1105/tpc.010008] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2001] [Accepted: 04/20/2001] [Indexed: 05/20/2023]
Abstract
Plant heterotrimeric G-proteins have been implicated in a number of signaling processes. However, most of these studies are based on biochemical or pharmacological approaches. To examine the role of heterotrimeric G-proteins in plant development, we generated transgenic Arabidopsis expressing the Galpha subunit of the heterotrimeric G-protein under the control of a glucocorticoid-inducible promoter. With the conditional overexpression of either the wild type or a constitutively active version of Arabidopsis Galpha, transgenic seedlings exhibited a hypersensitive response to light. This enhanced light sensitivity was more exaggerated in a relatively lower intensity of light and was observed in white light as well as far-red, red, and blue light conditions. The enhanced responses in far-red and red light required functional phytochrome A and phytochrome B, respectively. Furthermore, the response to far-red light depended on functional FHY1 but not on FIN219 and FHY3. This dependence on FHY1 indicates that the Arabidopsis Galpha protein may act only on a discrete branch of the phytochrome A signaling pathway. Thus, our results support the involvement of a heterotrimeric G-protein in the light regulation of Arabidopsis seedling development.
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Affiliation(s)
- H Okamoto
- Department of Molecular, Cellular, and Developmental Biology, Yale University, 165 Prospect Street, New Haven, CT 06520-8104, USA
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Abstract
Heterotrimeric G-proteins, which couple cell surface receptors with internal effectors, are evident in all eukaryotes. Their operation involves receptor activation, GTP/GDP exchange and modulation of effector activity; deactivation occurs by an intrinsic GTPase activity. Structurally, G-proteins comprise three dissimilar subunits; Gα, Gβ and Gγ. The Gα subunit consists of an α-helical and a GTPase domain, the latter is responsible for interaction with Gβγ, receptor and effector. Gβ and Gγ form a tightly associated heterodimer which can also modulate effector activity when released by the activated Gα. Genome sequence and other data suggest that, in plants, there are several (~8-10?) Gα, one or two Gβ and one Gγ. These proteins are expressed throughout the plant, mainly in the plasma membrane and endoplasmic reticulum. In vivo, there is strong evidence for G-protein control of ion channels, particularly K+ , in the response pathways to fungal and bacterial pathogens as well as in some aspects of gibberellin, abscisic acid and auxin signaling pathways. Finally, future prospects for understanding plant G-protein linked signaling will rely on new and emerging technologies; these include antisense suppression, gene knockouts, yeast two-hybrid and phage display molecular approaches, intracellular immunization using recombinant single chain antibodies and expression of peptide encoding minigenes.
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Affiliation(s)
- P A Millner
- School of Biochemistry and Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
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