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Chen J, Yang L, Zhang H, Ruan J, Wang Y. Role of sugars in the apical hook development of Arabidopsis etiolated seedlings. PLANT CELL REPORTS 2024; 43:131. [PMID: 38656568 DOI: 10.1007/s00299-024-03217-8] [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: 02/02/2024] [Accepted: 04/14/2024] [Indexed: 04/26/2024]
Abstract
KEY MESSAGE The sugar supply in the medium affects the apical hook development of Arabidopsis etiolated seedlings. In addition, we provided the mechanism insights of this process. Dicotyledonous plants form an apical hook structure to shield their young cotyledons from mechanical damage as they emerge from the rough soil. Our findings indicate that sugar molecules, such as sucrose and glucose, are crucial for apical hook development. The presence of sucrose and glucose allows the apical hooks to be maintained for a longer period compared to those grown in sugar-free conditions, and this effect is dose-dependent. Key roles in apical hook development are played by several sugar metabolism pathways, including oxidative phosphorylation and glycolysis. RNA-seq data revealed an up-regulation of genes involved in starch and sucrose metabolism in plants grown in sugar-free conditions, while genes associated with phenylpropanoid metabolism were down-regulated. This study underscores the significant role of sugar metabolism in the apical hook development of etiolated Arabidopsis seedlings.
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Affiliation(s)
- Jiahong Chen
- State Key Laboratory of Plant Molecular Genetics, Center of Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Lei Yang
- The Engineering Research Institute of Agriculture and Forestry, Ludong University, Yantai, 264025, China.
| | - Hehua Zhang
- Shanghai University of Medicine & Health Sciences, Shanghai, 201318, China
| | - Junbin Ruan
- Shanghai University of Medicine & Health Sciences, Shanghai, 201318, China
| | - Yuan Wang
- State Key Laboratory of Plant Molecular Genetics, Center of Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China.
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2
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Zhang J, Chen W, Li X, Shi H, Lv M, He L, Bai W, Cheng S, Chu J, He K, Gou X, Li J. Jasmonates regulate apical hook development by repressing brassinosteroid biosynthesis and signaling. PLANT PHYSIOLOGY 2023; 193:1561-1579. [PMID: 37467431 PMCID: PMC10517256 DOI: 10.1093/plphys/kiad399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 05/31/2023] [Indexed: 07/21/2023]
Abstract
An apical hook is a special structure formed during skotomorphogenesis in dicotyledonous plant species. It is critical for protecting the shoot apical meristem from mechanical damage during seed germination and hypocotyl elongation in soil. Brassinosteroid (BR) and jasmonate (JA) phytohormones antagonistically regulate apical hook formation. However, the interrelationship between BRs and JAs in this process has not been well elucidated. Here, we reveal that JAs repress BRs to regulate apical hook development in Arabidopsis (Arabidopsis thaliana). Exogenous application of methyl jasmonate (MeJA) repressed the expression of the rate-limiting BR biosynthetic gene DWARF4 (DWF4) in a process relying on 3 key JA-dependent transcription factors, MYC2, MYC3, and MYC4. We demonstrated that MYC2 interacts with the critical BR-activated transcription factor BRASSINAZOLE RESISTANT 1 (BZR1), disrupting the association of BZR1 with its partner transcription factors, such as those of the PHYTOCHROME INTERACTING FACTOR (PIF) family and downregulating the expression of their target genes, such as WAVY ROOT GROWTH 2 (WAG2), encoding a protein kinase essential for apical hook development. Our results indicate that JAs not only repress the expression of BR biosynthetic gene DWF4 but, more importantly, attenuate BR signaling by inhibiting the transcriptional activation of BZR1 by MYC2 during apical hook development.
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Affiliation(s)
- Jingjie Zhang
- Guangdong Provincial Key Laboratory of Plant Adaptation and Molecular Design, School of Life Sciences, Guangzhou University, Guangzhou 510006, China
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Weiyue Chen
- Guangdong Provincial Key Laboratory of Plant Adaptation and Molecular Design, School of Life Sciences, Guangzhou University, Guangzhou 510006, China
| | - Xiaopeng Li
- Guangdong Provincial Key Laboratory of Plant Adaptation and Molecular Design, School of Life Sciences, Guangzhou University, Guangzhou 510006, China
| | - Hongyong Shi
- Guangdong Provincial Key Laboratory of Plant Adaptation and Molecular Design, School of Life Sciences, Guangzhou University, Guangzhou 510006, China
| | - Minghui Lv
- Guangdong Provincial Key Laboratory of Plant Adaptation and Molecular Design, School of Life Sciences, Guangzhou University, Guangzhou 510006, China
| | - Liming He
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Wenhua Bai
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Shujing Cheng
- National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Jinfang Chu
- National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kai He
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Xiaoping Gou
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Jia Li
- Guangdong Provincial Key Laboratory of Plant Adaptation and Molecular Design, School of Life Sciences, Guangzhou University, Guangzhou 510006, China
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
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Zhao N, Zhao M, Tian Y, Wang Y, Han C, Fan M, Guo H, Bai MY. Interaction between BZR1 and EIN3 mediates signalling crosstalk between brassinosteroids and ethylene. THE NEW PHYTOLOGIST 2021; 232:2308-2323. [PMID: 34449890 DOI: 10.1111/nph.17694] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 08/20/2021] [Indexed: 06/13/2023]
Abstract
Plant growth and development are coordinated by multiple environmental and endogenous signals. Brassinosteroid (BR) and ethylene (ET) have overlapping functions in a wide range of developmental processes. However, the relationship between the BR and ET signalling pathways has remained unclear. Here, we show that BR and ET interdependently promote apical hook development and cell elongation through a direct interaction between BR-activated BRASSINOZALE-RESISTANT1 (BZR1) and ET-activated ETHYLENE INSENSITIVE3 (EIN3). Genetic analysis showed that BR signalling is required for ET promotion of apical hook development in the dark and cell elongation under light, and ET quantitatively enhances BR-potentiated growth. BZR1 interacts with EIN3 to co-operatively increase the expression of HOOKLESS1 and PACLOBUTRAZOL RESISTANCE FACTORs (PREs). Furthermore, we found that BR promotion of hook development requires gibberellin (GA), and GA restores the hookless phenotype of BR-deficient materials by activating EIN3/EIL1. Our findings shed light on the molecular mechanism underlying the regulation of plant development by BR, ET and GA signals through the direct interaction of master transcriptional regulators.
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Affiliation(s)
- Na Zhao
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Science, Shandong University, Qingdao, 266237, China
| | - Min Zhao
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Science, Shandong University, Qingdao, 266237, China
| | - Yanchen Tian
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Science, Shandong University, Qingdao, 266237, China
| | - Yichuan Wang
- Department of Biology, Institute of Plant and Food Science, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Chao Han
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Science, Shandong University, Qingdao, 266237, China
| | - Min Fan
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Science, Shandong University, Qingdao, 266237, China
| | - Hongwei Guo
- Department of Biology, Institute of Plant and Food Science, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Ming-Yi Bai
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Science, Shandong University, Qingdao, 266237, China
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4
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Zhang C, He M, Wang S, Chu L, Wang C, Yang N, Ding G, Cai H, Shi L, Xu F. Boron deficiency-induced root growth inhibition is mediated by brassinosteroid signalling regulation in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 107:564-578. [PMID: 33964043 DOI: 10.1111/tpj.15311] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Revised: 04/23/2021] [Accepted: 05/03/2021] [Indexed: 05/12/2023]
Abstract
Brassinosteroids (BRs) are pivotal phytohormones involved in the control of root development. Boron (B) is an essential micronutrient for plants, and root growth is rapidly inhibited under B deficiency conditions. However, the mechanisms underlying this inhibition are still unclear. Here, we identified BR-related processes underlying B deficiency at the physiological, genetic, molecular/cell biological and transcriptomic levels and found strong evidence that B deficiency can affect BR biosynthesis and signalling, thereby altering root growth. RNA sequencing analysis revealed strong co-regulation between BR-regulated genes and B deficiency-responsive genes. We found that the BR receptor mutants bri1-119 and bri1-301 were more insensitive to decreased B supply, and the gain-of-function mutants bes1-D and pBZR1-bzr1-D exhibited insensitivity to low-B stress. Under B deficiency conditions, exogenous 24-epibrassinolide rescued the inhibition of root growth, and application of the BR biosynthesis inhibitor brassinazole exacerbated this inhibitory effect. The nuclear-localised signal of BES1 was reduced under low-B conditions compared with B sufficiency conditions. We further found that B deficiency hindered the accumulation of brassinolide to downregulate BR signalling and modulate root elongation, which may occur through a reduction in BR6ox1 and BR6ox2 mRNA levels. Taken together, our results reveal a role of BR signalling in root elongation under B deficiency.
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Affiliation(s)
- Cheng Zhang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- Microelement Research Center/Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Mingliang He
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- Microelement Research Center/Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Sheliang Wang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- Microelement Research Center/Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Liuyang Chu
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- Microelement Research Center/Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Chuang Wang
- Microelement Research Center/Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Ningmei Yang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- Microelement Research Center/Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Guangda Ding
- Microelement Research Center/Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Hongmei Cai
- Microelement Research Center/Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Lei Shi
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- Microelement Research Center/Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Fangsen Xu
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
- Microelement Research Center/Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
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Bajguz A, Chmur M, Gruszka D. Comprehensive Overview of the Brassinosteroid Biosynthesis Pathways: Substrates, Products, Inhibitors, and Connections. FRONTIERS IN PLANT SCIENCE 2020; 11:1034. [PMID: 32733523 PMCID: PMC7358554 DOI: 10.3389/fpls.2020.01034] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 06/24/2020] [Indexed: 05/06/2023]
Abstract
Brassinosteroids (BRs) as a class of steroid plant hormones participate in the regulation of numerous developmental processes, including root and shoot growth, vascular differentiation, fertility, flowering, and seed germination, as well as in responding to environmental stresses. During four decades of research, the BR biosynthetic pathways have been well studied with forward- and reverse genetics approaches. The free BRs contain 27, 28, and 29 carbons within their skeletal structure: (1): 5α-cholestane or 26-nor-24α-methyl-5α-cholestane for C27-BRs; (2) 24α-methyl-5α-cholestane, 24β-methyl-5α-cholestane or 24-methylene-5α-cholestane for C28-BRs; (3) 24α-ethyl-5α-cholestane, 24(Z)-ethylidene-5α-cholestane, 25-methyl-5α-campestane or 24-methylene-25-methyl-5α-cholestane for C29-BRs, as well as different kinds and orientations of oxygenated functions in A- and B-ring. These alkyl substituents are also common structural features of sterols. BRs are derived from sterols carrying the same side chain. The C27-BRs without substituent at C-24 are biosynthesized from cholesterol. The C28-BRs carrying either an α-methyl, β-methyl, or methylene group are derived from campesterol, 24-epicampesterol or 24-methylenecholesterol, respectively. The C29-BRs with an α-ethyl group are produced from sitosterol. Furthermore, the C29 BRs carrying methylene at C-24 and an additional methyl group at C-25 are derived from 24-methylene-25-methylcholesterol. Generally, BRs are biosynthesized via cycloartenol and cycloartanol dependent pathways. Till now, more than 17 compounds were characterized as inhibitors of the BR biosynthesis. For nine of the inhibitors (e.g., brassinazole and YCZ-18) a specific target reaction within the BR biosynthetic pathway has been identified. Therefore, the review highlights comprehensively recent advances in our understanding of the BR biosynthesis, sterol precursors, and dependencies between the C27-C28 and C28-C29 pathways.
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Affiliation(s)
- Andrzej Bajguz
- Faculty of Biology, University of Bialystok, Bialystok, Poland
- *Correspondence: Andrzej Bajguz,
| | - Magdalena Chmur
- Faculty of Biology, University of Bialystok, Bialystok, Poland
| | - Damian Gruszka
- Faculty of Natural Sciences, Institute of Biology, Biotechnology and Environmental Protection, University of Silesia, Katowice, Poland
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Rozhon W, Akter S, Fernandez A, Poppenberger B. Inhibitors of Brassinosteroid Biosynthesis and Signal Transduction. Molecules 2019; 24:E4372. [PMID: 31795392 PMCID: PMC6930552 DOI: 10.3390/molecules24234372] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 11/25/2019] [Accepted: 11/26/2019] [Indexed: 12/19/2022] Open
Abstract
Chemical inhibitors are invaluable tools for investigating protein function in reverse genetic approaches. Their application bears many advantages over mutant generation and characterization. Inhibitors can overcome functional redundancy, their application is not limited to species for which tools of molecular genetics are available and they can be applied to specific tissues or developmental stages, making them highly convenient for addressing biological questions. The use of inhibitors has helped to elucidate hormone biosynthesis and signaling pathways and here we review compounds that were developed for the plant hormones brassinosteroids (BRs). BRs are steroids that have strong growth-promoting capacities, are crucial for all stages of plant development and participate in adaptive growth processes and stress response reactions. In the last two decades, impressive progress has been made in BR inhibitor development and application, which has been instrumental for studying BR modes of activity and identifying and characterizing key players. Both, inhibitors that target biosynthesis, such as brassinazole, and inhibitors that target signaling, such as bikinin, exist and in a comprehensive overview we summarize knowledge and methodology that enabled their design and key findings of their use. In addition, the potential of BR inhibitors for commercial application in plant production is discussed.
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Affiliation(s)
- Wilfried Rozhon
- Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Liesel-Beckmann-Straße 1, 85354 Freising, Germany
| | | | | | - Brigitte Poppenberger
- Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Liesel-Beckmann-Straße 1, 85354 Freising, Germany
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Song L, Chen W, Wang B, Yao QM, Valliyodan B, Bai MY, Zhao MZ, Ye H, Wang ZY, Nguyen HT. GmBZL3 acts as a major BR signaling regulator through crosstalk with multiple pathways in Glycine max. BMC PLANT BIOLOGY 2019; 19:86. [PMID: 30795735 PMCID: PMC6387493 DOI: 10.1186/s12870-019-1677-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 02/07/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND Brassinosteroids (BRs) play a crucial role in plant vegetative growth and reproductive development. The transcription factors BZR1 and BES1/BZR2 are well characterized as downstream regulators of the BR signaling pathway in Arabidopsis and rice. Soybean contains four BZR1-like proteins (GmBZLs), and it was reported that GmBZL2 plays a conserved role in BR signaling regulation. However, the roles of other GmBZLs have not been thoroughly studied, and the targets of GmBZLs in soybean remain unclear. RESULTS In this study, we first characterized GmBZL3 in soybean from gene expression patterns, conserved domains in coding sequences, and genomic replication times of four GmBZL orthologous. The results indicated that GmBZL3 might play conserved roles during soybean development. The overexpression of GmBZL3P219L in the Arabidopsis BR-insensitive mutant bri1-5 partially rescued the phenotypic defects including BR-insensitivity, which provides further evidence that GmBZL3 functions are conserved between soybean and the homologous Arabidopsis genes. In addition, the identification of the GmBZL3 target genes through ChIP-seq technology revealed that BR has broad roles in soybean and regulates multiple pathways, including other hormone signaling, disease-related, and immunity response pathways. Moreover, the BR-regulated GmBZL3 target genes were further identified, and the results demonstrate that GmBZL3 is a major transcription factor responsible for BR-regulated gene expression and soybean growth. A comparison of GmBZL3 and AtBZR1/BES1 targets demonstrated that GmBZL3 might play conserved as well as specific roles in the soybean BR signaling network. Finally, the identification of two natural soybean varieties of the GmBZL3 mutantion by SNP analysis could facilitate the understanding of gene function during soybean development in the future. CONCLUSIONS We illustrate here that GmBZL3 orchestrates a genome-wide transcriptional response that underlies BR-mediated soybean early vegetative growth, and our results support that BRs play crucial regulatory roles in soybean morphology and gene expression levels.
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Affiliation(s)
- Li Song
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009 China
- Division of Plant Sciences, University of Missouri, Columbia, MO 65211 USA
| | - Wei Chen
- Division of Plant Sciences, University of Missouri, Columbia, MO 65211 USA
| | - Biao Wang
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240 China
| | - Qiu-Ming Yao
- Department of Computer Science, Informatics Institute, and Christopher S. Bond Life, Sciences Center, University of Missouri, Columbia, MO 65211 USA
| | - Babu Valliyodan
- Division of Plant Sciences, University of Missouri, Columbia, MO 65211 USA
| | - Ming-Yi Bai
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305 USA
- Present address: Shandong University, Jinan, Shandong China
| | - Ming-Zhe Zhao
- Division of Plant Sciences, University of Missouri, Columbia, MO 65211 USA
- Present address: Agronomy College of Shenyang Agricultural University, Shenyang, Liaoning China
| | - Heng Ye
- Division of Plant Sciences, University of Missouri, Columbia, MO 65211 USA
| | - Zhi-Yong Wang
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305 USA
| | - Henry T. Nguyen
- Division of Plant Sciences, University of Missouri, Columbia, MO 65211 USA
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Yuan DP, Zhang C, Wang ZY, Zhu XF, Xuan YH. RAVL1 Activates Brassinosteroids and Ethylene Signaling to Modulate Response to Sheath Blight Disease in Rice. PHYTOPATHOLOGY 2018; 108:1104-1113. [PMID: 29767552 DOI: 10.1094/phyto-03-18-0085-r] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Rhizoctonia solani causes sheath blight disease in rice; however, the defense mechanism of rice plants against R. solani remains elusive. To analyze the roles of brassinosteroid (BR) and ethylene signaling on rice defense to R. solani, wild-type (WT) rice and several mutants and overexpressing (OX) lines were inoculated with R. solani. Mutants d61-1 and d2 were less susceptible to sheath blight disease, bri1-D was more susceptible, and ravl1 and d61-1/EIL1 Ri5 were similarly susceptible compared with WT. The double mutant ravl1/d61-1 was phenotypically similar to the ravl1 mutant. Transcriptome analysis, chromatin immunoprecipitation assay, electrophoretic mobility shift assay, and transient assays indicted that RAVL1 might directly activate Ethylene insensitive 3-like 1 (EIL1), a master regulator of ethylene signaling. Mutants ers1 and d61-1/RAVL1 OX were resistant to sheath blight disease, whereas EIL1 RNAi mutants and RAVL1 OX were more susceptible than WT. BRI1 and D2 expression in EIL1 Ri5/RAVL1 OX and EIL1 expression in d61-1/RAVL1 OX indicated that RAVL1 activates BRI1/D2 and EIL1, respectively, independent of BR and ethylene signaling. Our analyses provide information on how BR and ethylene signaling regulate sheath blight disease and on the regulatory function of RAVL1 in rice sheath blight disease.
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Affiliation(s)
- De Peng Yuan
- All authors: College of Plant Protection, Shenyang Agricultural University, Shenyang, Liaoning, 110866 China
| | - Chong Zhang
- All authors: College of Plant Protection, Shenyang Agricultural University, Shenyang, Liaoning, 110866 China
| | - Zi Yuan Wang
- All authors: College of Plant Protection, Shenyang Agricultural University, Shenyang, Liaoning, 110866 China
| | - Xiao Feng Zhu
- All authors: College of Plant Protection, Shenyang Agricultural University, Shenyang, Liaoning, 110866 China
| | - Yuan Hu Xuan
- All authors: College of Plant Protection, Shenyang Agricultural University, Shenyang, Liaoning, 110866 China
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Identification of Chemical Inducers of the Phosphate-Starvation Signaling Pathway in A. thaliana Using Chemical Genetics. Methods Mol Biol 2018; 1795:65-84. [PMID: 29846919 DOI: 10.1007/978-1-4939-7874-8_6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
In spite of its importance for agriculture and 30 years of genetic studies, the phosphate-starvation signaling pathway, that allows plants to detect, respond, and adapt to changes in the phosphate concentration of the rhizosphere, remains poorly known. Chemical genetics has been increasingly and successfully used as a complementary approach to genetics for the dissection of signaling pathways in diverse organisms. Screens can be designed to identify chemicals interfering specifically with a pathway of interest. We designed a screen that led to the discovery of the first chemical capable to induce specifically the phosphate-starvation signaling pathway in Arabidopsis thaliana. This procedure, described here, can be adapted for the discovery of inducers or repressors of other pathways.
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Hu Y, Depaepe T, Smet D, Hoyerova K, Klíma P, Cuypers A, Cutler S, Buyst D, Morreel K, Boerjan W, Martins J, Petrášek J, Vandenbussche F, Van Der Straeten D. ACCERBATIN, a small molecule at the intersection of auxin and reactive oxygen species homeostasis with herbicidal properties. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:4185-4203. [PMID: 28922768 PMCID: PMC5853866 DOI: 10.1093/jxb/erx242] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 06/22/2017] [Indexed: 05/30/2023]
Abstract
The volatile two-carbon hormone ethylene acts in concert with an array of signals to affect etiolated seedling development. From a chemical screen, we isolated a quinoline carboxamide designated ACCERBATIN (AEX) that exacerbates the 1-aminocyclopropane-1-carboxylic acid-induced triple response, typical for ethylene-treated seedlings in darkness. Phenotypic analyses revealed distinct AEX effects including inhibition of root hair development and shortening of the root meristem. Mutant analysis and reporter studies further suggested that AEX most probably acts in parallel to ethylene signaling. We demonstrated that AEX functions at the intersection of auxin metabolism and reactive oxygen species (ROS) homeostasis. AEX inhibited auxin efflux in BY-2 cells and promoted indole-3-acetic acid (IAA) oxidation in the shoot apical meristem and cotyledons of etiolated seedlings. Gene expression studies and superoxide/hydrogen peroxide staining further revealed that the disrupted auxin homeostasis was accompanied by oxidative stress. Interestingly, in light conditions, AEX exhibited properties reminiscent of the quinoline carboxylate-type auxin-like herbicides. We propose that AEX interferes with auxin transport from its major biosynthesis sites, either as a direct consequence of poor basipetal transport from the shoot meristematic region, or indirectly, through excessive IAA oxidation and ROS accumulation. Further investigation of AEX can provide new insights into the mechanisms connecting auxin and ROS homeostasis in plant development and provide useful tools to study auxin-type herbicides.
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Affiliation(s)
- Yuming Hu
- Laboratory of Functional Plant Biology, Department of Biology, Faculty of Sciences, Ghent University, K.L. Ledeganckstraat, Ghent, Belgium
| | - Thomas Depaepe
- Laboratory of Functional Plant Biology, Department of Biology, Faculty of Sciences, Ghent University, K.L. Ledeganckstraat, Ghent, Belgium
| | - Dajo Smet
- Laboratory of Functional Plant Biology, Department of Biology, Faculty of Sciences, Ghent University, K.L. Ledeganckstraat, Ghent, Belgium
| | - Klara Hoyerova
- Institute of Experimental Botany ASCR, Praha, Czech Republic
| | - Petr Klíma
- Institute of Experimental Botany ASCR, Praha, Czech Republic
| | - Ann Cuypers
- Centre for Environmental Sciences, Hasselt University, Agoralaan Building D, Diepenbeek, Belgium
| | - Sean Cutler
- Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside, CA, USA
| | - Dieter Buyst
- NMR and Structure Analysis, Department of Organic Chemistry, Krijgslaan, Ghent, Belgium
| | - Kris Morreel
- Department of Plant Systems Biology, VIB (Flanders Institute for Biotechnology), Technologiepark, Ghent, Belgium
| | - Wout Boerjan
- Department of Plant Systems Biology, VIB (Flanders Institute for Biotechnology), Technologiepark, Ghent, Belgium
| | - José Martins
- NMR and Structure Analysis, Department of Organic Chemistry, Krijgslaan, Ghent, Belgium
| | - Jan Petrášek
- Institute of Experimental Botany ASCR, Praha, Czech Republic
| | - Filip Vandenbussche
- Laboratory of Functional Plant Biology, Department of Biology, Faculty of Sciences, Ghent University, K.L. Ledeganckstraat, Ghent, Belgium
| | - Dominique Van Der Straeten
- Laboratory of Functional Plant Biology, Department of Biology, Faculty of Sciences, Ghent University, K.L. Ledeganckstraat, Ghent, Belgium
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11
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Dejonghe W, Russinova E. Plant Chemical Genetics: From Phenotype-Based Screens to Synthetic Biology. PLANT PHYSIOLOGY 2017; 174:5-20. [PMID: 28275150 PMCID: PMC5411137 DOI: 10.1104/pp.16.01805] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 02/20/2017] [Indexed: 05/21/2023]
Abstract
The treatment of a biological system with small molecules to specifically perturb cellular functions is commonly referred to as chemical biology. Small molecules are used commercially as drugs, herbicides, and fungicides in different systems, but in recent years they are increasingly exploited as tools for basic research. For instance, chemical genetics involves the discovery of small-molecule effectors of various cellular functions through screens of compound libraries. Whereas the drug discovery field has largely been driven by target-based screening approaches followed by drug optimization, chemical genetics in plant systems tends to be fueled by more general phenotype-based screens, opening the possibility to identify a wide range of small molecules that are not necessarily directly linked to the process of interest. Here, we provide an overview of the current progress in chemical genetics in plants, with a focus on the discoveries regarding small molecules identified in screens designed with a basic biology perspective. We reflect on the possibilities that lie ahead and discuss some of the potential pitfalls that might be encountered upon adopting a given chemical genetics approach.
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Affiliation(s)
- Wim Dejonghe
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium (W.D., E.R); and
- Center for Plant Systems Biology, VIB, 9052 Ghent, Belgium (W.D., E.R.)
| | - Eugenia Russinova
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium (W.D., E.R); and
- Center for Plant Systems Biology, VIB, 9052 Ghent, Belgium (W.D., E.R.)
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12
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Burrell T, Fozard S, Holroyd GH, French AP, Pound MP, Bigley CJ, James Taylor C, Forde BG. The Microphenotron: a robotic miniaturized plant phenotyping platform with diverse applications in chemical biology. PLANT METHODS 2017; 13:10. [PMID: 28265297 PMCID: PMC5333401 DOI: 10.1186/s13007-017-0158-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 02/02/2017] [Indexed: 05/06/2023]
Abstract
BACKGROUND Chemical genetics provides a powerful alternative to conventional genetics for understanding gene function. However, its application to plants has been limited by the lack of a technology that allows detailed phenotyping of whole-seedling development in the context of a high-throughput chemical screen. We have therefore sought to develop an automated micro-phenotyping platform that would allow both root and shoot development to be monitored under conditions where the phenotypic effects of large numbers of small molecules can be assessed. RESULTS The 'Microphenotron' platform uses 96-well microtitre plates to deliver chemical treatments to seedlings of Arabidopsis thaliana L. and is based around four components: (a) the 'Phytostrip', a novel seedling growth device that enables chemical treatments to be combined with the automated capture of images of developing roots and shoots; (b) an illuminated robotic platform that uses a commercially available robotic manipulator to capture images of developing shoots and roots; (c) software to control the sequence of robotic movements and integrate these with the image capture process; (d) purpose-made image analysis software for automated extraction of quantitative phenotypic data. Imaging of each plate (representing 80 separate assays) takes 4 min and can easily be performed daily for time-course studies. As currently configured, the Microphenotron has a capacity of 54 microtitre plates in a growth room footprint of 2.1 m2, giving a potential throughput of up to 4320 chemical treatments in a typical 10 days experiment. The Microphenotron has been validated by using it to screen a collection of 800 natural compounds for qualitative effects on root development and to perform a quantitative analysis of the effects of a range of concentrations of nitrate and ammonium on seedling development. CONCLUSIONS The Microphenotron is an automated screening platform that for the first time is able to combine large numbers of individual chemical treatments with a detailed analysis of whole-seedling development, and particularly root system development. The Microphenotron should provide a powerful new tool for chemical genetics and for wider chemical biology applications, including the development of natural and synthetic chemical products for improved agricultural sustainability.
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Affiliation(s)
- Thomas Burrell
- Engineering Department, Lancaster University, Lancaster, LA1 4YR UK
| | - Susan Fozard
- Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ UK
| | - Geoff H. Holroyd
- Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ UK
| | - Andrew P. French
- The Centre for Plant Integrative Biology, School of Biosciences, Sutton Bonington Campus, University of Nottingham, Nottingham, LE12 5RD UK
- School of Computer Science, University of Nottingham, Jubilee Campus, Nottingham, NG8 1BB UK
| | - Michael P. Pound
- The Centre for Plant Integrative Biology, School of Biosciences, Sutton Bonington Campus, University of Nottingham, Nottingham, LE12 5RD UK
- School of Computer Science, University of Nottingham, Jubilee Campus, Nottingham, NG8 1BB UK
| | | | - C. James Taylor
- Engineering Department, Lancaster University, Lancaster, LA1 4YR UK
| | - Brian G. Forde
- Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ UK
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13
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Carland F, Defries A, Cutler S, Nelson T. Novel Vein Patterns in Arabidopsis Induced by Small Molecules. PLANT PHYSIOLOGY 2016; 170:338-53. [PMID: 26574596 PMCID: PMC4704596 DOI: 10.1104/pp.15.01540] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 11/03/2015] [Indexed: 05/03/2023]
Abstract
The critical role of veins in transporting water, nutrients, and signals suggests that some key regulators of vein formation may be genetically redundant and, thus, undetectable by forward genetic screens. To identify such regulators, we screened more than 5000 structurally diverse small molecules for compounds that alter Arabidopsis (Arabidopsis thaliana) leaf vein patterns. Many compound-induced phenotypes were observed, including vein networks with an open reticulum; decreased or increased vein number and thickness; and misaligned, misshapen, or nonpolar vascular cells. Further characterization of several individual active compounds suggests that their targets include hormone cross talk, hormone-dependent transcription, and PIN-FORMED trafficking.
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Affiliation(s)
- Francine Carland
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut 06520 (F.C., T.N.);Bloomfield Industries, Inc., Staten Island, New York 10314 (A.D.); andDepartment of Botany and Plant Sciences, University of California, Riverside, Riverside, California 92507 (S.C.)
| | - Andrew Defries
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut 06520 (F.C., T.N.);Bloomfield Industries, Inc., Staten Island, New York 10314 (A.D.); andDepartment of Botany and Plant Sciences, University of California, Riverside, Riverside, California 92507 (S.C.)
| | - Sean Cutler
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut 06520 (F.C., T.N.);Bloomfield Industries, Inc., Staten Island, New York 10314 (A.D.); andDepartment of Botany and Plant Sciences, University of California, Riverside, Riverside, California 92507 (S.C.)
| | - Timothy Nelson
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut 06520 (F.C., T.N.);Bloomfield Industries, Inc., Staten Island, New York 10314 (A.D.); andDepartment of Botany and Plant Sciences, University of California, Riverside, Riverside, California 92507 (S.C.)
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14
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Shi C, Qi C, Ren H, Huang A, Hei S, She X. Ethylene mediates brassinosteroid-induced stomatal closure via Gα protein-activated hydrogen peroxide and nitric oxide production in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 82:280-301. [PMID: 25754244 DOI: 10.1111/tpj.12815] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 02/14/2015] [Accepted: 02/23/2015] [Indexed: 05/07/2023]
Abstract
Brassinosteroids (BRs) are essential for plant growth and development; however, whether and how they promote stomatal closure is not fully clear. In this study, we report that 24-epibrassinolide (EBR), a bioactive BR, induces stomatal closure in Arabidopsis (Arabidopsis thaliana) by triggering a signal transduction pathway including ethylene synthesis, the activation of Gα protein, and hydrogen peroxide (H(2)O(2)) and nitric oxide (NO) production. EBR initiated a marked rise in ethylene, H(2)O(2) and NO levels, necessary for stomatal closure in the wild type. These effects were abolished in mutant bri1-301, and EBR failed to close the stomata of gpa1 mutants. Next, we found that both ethylene and Gα mediate the inductive effects of EBR on H(2)O(2) and NO production. EBR-triggered H(2)O(2) and NO accumulation were canceled in the etr1 and gpa1 mutants, but were strengthened in the eto1-1 mutant and the cGα line (constitutively overexpressing the G protein α-subunit AtGPA1). Exogenously applied H(2)O(2) or sodium nitroprusside (SNP) rescued the defects of etr1-3 and gpa1 or etr1 and gpa1 mutants in EBR-induced stomatal closure, whereas the stomata of eto1-1/AtrbohF and cGα/AtrbohF or eto1-1/nia1-2 and cGα/nia1-2 constructs had an analogous response to H(2)O(2) or SNP as those of AtrbohF or Nia1-2 mutants. Moreover, we provided evidence that Gα plays an important role in the responses of guard cells to ethylene. Gα activator CTX largely restored the lesion of the etr1-3 mutant, but ethylene precursor ACC failed to rescue the defects of gpa1 mutants in EBR-induced stomatal closure. Lastly, we demonstrated that Gα-activated H(2)O(2) production is required for NO synthesis. EBR failed to induce NO synthesis in mutant AtrbohF, but it led to H(2)O(2) production in mutant Nia1-2. Exogenously applied SNP rescued the defect of AtrbohF in EBR-induced stomatal closure, but H(2)O(2) did not reverse the lesion of EBR-induced stomatal closure in Nia1-2. Together, our results strongly suggest a signaling pathway in which EBR induces ethylene synthesis, thereby activating Gα, and then promotes AtrbohF-dependent H(2)O(2) production and subsequent Nia1-catalyzed NO accumulation, and finally closes stomata.
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Affiliation(s)
- Chenyu Shi
- School of Life Sciences, Shaanxi Normal University, Xi'an, 710062, China; School of Chemistry and Bioengineering, Hechi University, Yizhou, 546300, China
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15
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Jeong S, Kim JY, Choi H, Kim H, Lee I, Soh MS, Nam HG, Chang YT, Lim PO, Woo HR. Rootin, a compound that inhibits root development through modulating PIN-mediated auxin distribution. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2015; 233:116-126. [PMID: 25711819 DOI: 10.1016/j.plantsci.2015.01.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 12/31/2014] [Accepted: 01/09/2015] [Indexed: 06/04/2023]
Abstract
Plant roots anchor the plant to the soil and absorb water and nutrients for growth. Understanding the molecular mechanisms regulating root development is essential for improving plant survival and agricultural productivity. Extensive molecular genetic studies have provided important information on crucial components for the root development control over the last few decades. However, it is becoming difficult to identify new regulatory components in root development due to the functional redundancy and lethality of genes involved in root development. In this study, we performed a chemical genetic screen to identify novel synthetic compounds that regulate root development in Arabidopsis seedlings. The screen yielded a root growth inhibitor designated as 'rootin', which inhibited Arabidopsis root development by modulating cell division and elongation, but did not significantly affect shoot development. Transcript analysis of phytohormone marker genes revealed that rootin preferentially altered the expression of auxin-regulated genes. Furthermore, rootin reduced the accumulation of PIN1, PIN3, and PIN7 proteins, and affected the auxin distribution in roots, which consequently may lead to the observed defects in root development. Our results suggest that rootin could be utilized to unravel the mechanisms underlying root development and to investigate dynamic changes in PIN-mediated auxin distribution.
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Affiliation(s)
- Suyeong Jeong
- Department of Life Sciences, POSTECH, Hyojadong, Pohang, Gyeongbuk 790-784, Republic of Korea
| | - Jun-Young Kim
- Department of Chemistry, NUS & Singapore Bioimaging Consortium, A*STAR, Singapore 117543, Singapore
| | - Hyunmo Choi
- Department of Integrative Bioscience and Biotechnology, Sejong University, 98 Gunja-Dong, Gwangjin-Gu, Seoul 143-747, Republic of Korea
| | - Hyunmin Kim
- Department of Life Sciences, POSTECH, Hyojadong, Pohang, Gyeongbuk 790-784, Republic of Korea
| | - Ilhwan Lee
- Department of Life Sciences, POSTECH, Hyojadong, Pohang, Gyeongbuk 790-784, Republic of Korea
| | - Moon-Soo Soh
- Department of Integrative Bioscience and Biotechnology, Sejong University, 98 Gunja-Dong, Gwangjin-Gu, Seoul 143-747, Republic of Korea
| | - Hong Gil Nam
- Center for Plant Aging Research, Institute for Basic Science (IBS), Republic of Korea; Department of New Biology, DGIST, Daegu 711-873, Republic of Korea
| | - Young-Tae Chang
- Department of Chemistry, NUS & Singapore Bioimaging Consortium, A*STAR, Singapore 117543, Singapore.
| | - Pyung Ok Lim
- Department of New Biology, DGIST, Daegu 711-873, Republic of Korea.
| | - Hye Ryun Woo
- Department of New Biology, DGIST, Daegu 711-873, Republic of Korea.
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16
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Halder V, Kombrink E. Facile high-throughput forward chemical genetic screening by in situ monitoring of glucuronidase-based reporter gene expression in Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2015; 6:13. [PMID: 25688251 PMCID: PMC4310277 DOI: 10.3389/fpls.2015.00013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 01/07/2015] [Indexed: 05/20/2023]
Abstract
The use of biologically active small molecules to perturb biological functions holds enormous potential for investigating complex signaling networks. However, in contrast to animal systems, the search for and application of chemical tools for basic discovery in the plant sciences, generally referred to as "chemical genetics," has only recently gained momentum. In addition to cultured cells, the well-characterized, small-sized model plant Arabidopsis thaliana is suitable for cultivation in microplates, which allows employing diverse cell- or phenotype-based chemical screens. In such screens, a chemical's bioactivity is typically assessed either through scoring its impact on morphological traits or quantifying molecular attributes such as enzyme or reporter activities. Here, we describe a facile forward chemical screening methodology for intact Arabidopsis seedlings harboring the β-glucuronidase (GUS) reporter by directly quantifying GUS activity in situ with 4-methylumbelliferyl-β-D-glucuronide (4-MUG) as substrate. The quantitative nature of this screening assay has an obvious advantage over the also convenient histochemical GUS staining method, as it allows application of statistical procedures and unbiased hit selection based on threshold values as well as distinction between compounds with strong or weak bioactivity. At the same time, the in situ bioassay is very convenient requiring less effort and time for sample handling in comparison to the conventional quantitative in vitro GUS assay using 4-MUG, as validated with several Arabidopsis lines harboring different GUS reporter constructs. To demonstrate that the developed assays is particularly suitable for large-scale screening projects, we performed a pilot screen for chemical activators or inhibitors of salicylic acid-mediated defense signaling using the Arabidopsis PR1p::GUS line. Importantly, the screening methodology provided here can be adopted for any inducible GUS reporter line.
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Affiliation(s)
| | - Erich Kombrink
- *Correspondence: Erich Kombrink, Chemical Biology Laboratory, Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, 50829 Cologne, Germany e-mail:
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17
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Singh M, Gupta A, Laxmi A. Ethylene acts as a negative regulator of glucose induced lateral root emergence in Arabidopsis. PLANT SIGNALING & BEHAVIOR 2015; 10:e1058460. [PMID: 26236960 PMCID: PMC4883975 DOI: 10.1080/15592324.2015.1058460] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Plants, being sessile organisms, are more exposed to the hazards of constantly changing environmental conditions globally. During the lifetime of a plant, the root system encounters various challenges such as obstacles, pathogens, high salinity, water logging, nutrient scarcity etc. The developmental plasticity of the root system provides brilliant adaptability to plants to counter the changes exerted by both external as well as internal cues and achieve an optimized growth status. Phytohormones are one of the major intrinsic factors regulating all aspects of plant growth and development both independently as well as through complex signal integrations at multiple levels. We have previously shown that glucose (Glc) and brassinosteroid (BR) signalings interact extensively to regulate lateral root (LR) development in Arabidopsis. (1) Auxin efflux as well as influx and downstream signaling components are also involved in Glc-BR regulation of LR emergence. Here, we provide evidence for involvement of ethylene signaling machinery downstream to Glc and BR in regulation of LR emergence.
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Affiliation(s)
- Manjul Singh
- National Institute of Plant Genome Research; Aruna Asaf Ali Marg; New Delhi, India
| | - Aditi Gupta
- National Institute of Plant Genome Research; Aruna Asaf Ali Marg; New Delhi, India
| | - Ashverya Laxmi
- National Institute of Plant Genome Research; Aruna Asaf Ali Marg; New Delhi, India
- Correspondence to: Ashverya Laxmi; E-mail:
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18
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Serrano M, Kombrink E, Meesters C. Considerations for designing chemical screening strategies in plant biology. FRONTIERS IN PLANT SCIENCE 2015; 6:131. [PMID: 25904921 PMCID: PMC4389374 DOI: 10.3389/fpls.2015.00131] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 02/18/2015] [Indexed: 05/03/2023]
Abstract
Traditionally, biologists regularly used classical genetic approaches to characterize and dissect plant processes. However, this strategy is often impaired by redundancy, lethality or pleiotropy of gene functions, which prevent the isolation of viable mutants. The chemical genetic approach has been recognized as an alternative experimental strategy, which has the potential to circumvent these problems. It relies on the capacity of small molecules to modify biological processes by specific binding to protein target(s), thereby conditionally modifying protein function(s), which phenotypically resemble mutation(s) of the encoding gene(s). A successful chemical screening campaign comprises three equally important elements: (1) a reliable, robust, and quantitative bioassay, which allows to distinguish between potent and less potent compounds, (2) a rigorous validation process for candidate compounds to establish their selectivity, and (3) an experimental strategy for elucidating a compound's mode of action and molecular target. In this review we will discuss details of this general strategy and additional aspects that deserve consideration in order to take full advantage of the power provided by the chemical approach to plant biology. In addition, we will highlight some success stories of recent chemical screenings in plant systems, which may serve as teaching examples for the implementation of future chemical biology projects.
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Affiliation(s)
- Mario Serrano
- Plant Biology, Department of Biology, University of FribourgFribourg, Switzerland
| | - Erich Kombrink
- Chemical Biology Laboratory, Max Planck Institute for Plant Breeding ResearchKöln, Germany
| | - Christian Meesters
- Chemical Biology Laboratory, Max Planck Institute for Plant Breeding ResearchKöln, Germany
- Department of Chemical Biology, Faculty of Biology, Center for Medical Biotechnology, University of Duisburg-EssenEssen, Germany
- *Correspondence: Christian Meesters, Chemical Biology Laboratory, Max Planck Institute for Plant Breeding Research, Carl-von-Linné Weg 10, 50829 Köln, Germany
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19
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Smet D, Žádníková P, Vandenbussche F, Benková E, Van Der Straeten D. Dynamic infrared imaging analysis of apical hook development in Arabidopsis: the case of brassinosteroids. THE NEW PHYTOLOGIST 2014; 202:1398-1411. [PMID: 24611517 DOI: 10.1111/nph.12751] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 02/03/2014] [Indexed: 05/06/2023]
Abstract
Germination of Arabidopsis seeds in darkness induces apical hook development, based on a tightly regulated differential growth coordinated by a multiple hormone cross-talk. Here, we endeavoured to clarify the function of brassinosteroids (BRs) and cross-talk with ethylene in hook development. An automated infrared imaging system was developed to study the kinetics of hook development in etiolated Arabidopsis seedlings. To ascertain the photomorphogenic control of hook opening, the system was equipped with an automatic light dimmer. We demonstrate that ethylene and BRs are indispensable for hook formation and maintenance. Ethylene regulation of hook formation functions partly through BRs, with BR feedback inhibition of ethylene action. Conversely, BR-mediated extension of hook maintenance functions partly through ethylene. Furthermore, we revealed that a short light pulse is sufficient to induce rapid hook opening. Our dynamic infrared imaging system allows high-resolution, kinetic imaging of up to 112 seedlings in a single experimental run. At this high throughput, it is ideally suited to rapidly gain insight in pathway networks. We demonstrate that BRs and ethylene cooperatively regulate apical hook development in a phase-dependent manner. Furthermore, we show that light is a predominant regulator of hook opening, inhibiting ethylene- and BR-mediated postponement of hook opening.
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Affiliation(s)
- Dajo Smet
- Laboratory of Functional Plant Biology, Department of Physiology, Ghent University, 9000, Gent, Belgium
| | - Petra Žádníková
- Department of Plant Systems Biology, Vlaams Instituut voor Biotechnologie (VIB), 9052, Gent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent, Belgium
| | - Filip Vandenbussche
- Laboratory of Functional Plant Biology, Department of Physiology, Ghent University, 9000, Gent, Belgium
| | - Eva Benková
- Institute of Science and Technology, 3400, Klosterneuburg, Austria
- Genomics and Proteomics of Plant Systems, Central European Institute of Technology, Masaryk University, 62500, Brno, Czech Republic
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20
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Frerigmann H, Gigolashvili T. MYB34, MYB51, and MYB122 distinctly regulate indolic glucosinolate biosynthesis in Arabidopsis thaliana. MOLECULAR PLANT 2014; 7:814-28. [PMID: 24431192 DOI: 10.1093/mp/ssu004] [Citation(s) in RCA: 195] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The MYB34, MYB51, and MYB122 transcription factors are known to regulate indolic glucosinolate (IG) biosynthesis in Arabidopsis thaliana. To determine the distinct regulatory potential of MYB34, MYB51, and MYB122, the accumulation of IGs in different parts of plants and upon treatment with plant hormones were analyzed in A. thaliana seedlings. It was shown that MYB34, MYB51, and MYB122 act together to control the biosynthesis of I3M in shoots and roots, with MYB34 controlling biosynthesis of IGs mainly in the roots, MYB51 regulating biosynthesis in shoots, and MYB122 having an accessory role in the biosynthesis of IGs. Analysis of glucosinolate levels in seedlings of myb34, myb51, myb122, myb34 myb51 double, and myb34 myb51 myb122 triple knockout mutants grown in the presence of abscisic acid (ABA), salicylic acid (SA), jasmonate (JA), or ethylene (ET) revealed that: (1) MYB51 is the central regulator of IG synthesis upon SA and ET signaling, (2) MYB34 is the key regulator upon ABA and JA signaling, and (3) MYB122 plays only a minor role in JA/ET-induced glucosinolate biosynthesis. The myb34 myb51 myb122 triple mutant is devoid of IGs, indicating that these three MYB factors are indispensable for IG production under standard growth conditions.
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Affiliation(s)
- Henning Frerigmann
- Botanical Institute and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne Biocenter, D-50674 Cologne, Germany
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21
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Meesters C, Kombrink E. Screening for bioactive small molecules by in vivo monitoring of luciferase-based reporter gene expression in Arabidopsis thaliana. Methods Mol Biol 2014; 1056:19-31. [PMID: 24306859 DOI: 10.1007/978-1-62703-592-7_3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Chemical genetics is a scientific strategy that utilizes bioactive small molecules as experimental tools to dissect biological processes. Bioactive compounds occurring in nature represent an enormous diversity of structures that potentially can be used as activators or inhibitors of biochemical pathways, transport processes, regulatory networks, or developmental programs. Screening methods to identify bioactive small molecules can vary greatly, ranging from visual evaluation of phenotypic alterations to quantifying biometric traits such as enzyme activities. Here, we describe a general methodology that permits identification of compounds modulating the expression of reporter genes in Arabidopsis thaliana seedlings. The selection of luciferase-based reporter systems has the advantage that it allows in vivo imaging of reporter gene activity in a semiquantitative manner without affecting plant viability. We chose an Arabidopsis line harboring the luciferase reporter under the control of the jasmonate-inducible LOX2 promoter to screen for either activators or inhibitors of gene expression. The outlined assay conditions can readily be applied to Arabidopsis lines containing other reporter genes. Thereby screening for small molecules affecting different signaling pathways and/or phenotypic responses is possible.
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Affiliation(s)
- Christian Meesters
- Department of Plant-Microbe Interactions, Max Planck Institute for Plant Breeding Research, Köln, Germany
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22
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Lin LC, Chueh CM, Wang LC. Investigating the phytohormone ethylene response pathway by chemical genetics. Methods Mol Biol 2014; 1056:63-77. [PMID: 24306863 DOI: 10.1007/978-1-62703-592-7_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Conventional mutant screening in forward genetics research is indispensible to understand the biological operation behind any given phenotype. However, several issues, such as functional redundancy and lethality or sterility resulting from null mutations, frequently impede the functional characterization of genetic mutants. As an alternative approach, chemical screening with natural products or synthetic small molecules that act as conditional mutagens allows for identifying bioactive compounds as bioprobes to overcome the above-mentioned issues. Ethylene is the simplest olefin and is one of the major phytohormones playing crucial roles in plant physiology. Most of the current information on how ethylene works in plants came primarily from genetic studies of ethylene mutants identified by conventional genetic screening two decades ago. However, we lack a complete picture of functional interaction among components in the ethylene pathway and cross talk of ethylene with other phytohormones. Here, we describe our methodology for using chemical genetics to identify small molecules that interfere with the ethylene response. We set up a phenotype-based screening platform and a reporter gene-based system for verification of the hit compounds identified by chemical screening. We have successfully identified small molecules affecting the ethylene phenotype in etiolated seedlings and showed that a group of structurally similar compounds are novel inhibitors of ACC synthase, a rate-limiting enzyme in the ethylene biosynthesis pathway.
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Affiliation(s)
- Lee-Chung Lin
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
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23
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Singh M, Gupta A, Laxmi A. Glucose and phytohormone interplay in controlling root directional growth in Arabidopsis. PLANT SIGNALING & BEHAVIOR 2014; 9:e29219. [PMID: 25763496 PMCID: PMC4203494 DOI: 10.4161/psb.29219] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Sensing and responding toward gravity vector is a complicated and multistep process. Gravity is a constant factor feeding plants with reliable information for the spatial orientation of their organs. Auxin, cytokinin, ethylene and BRs have been the most explored hormones in relation to gravitropism. We have previously shown that glucose (Glc) could promote brassinosteroid (BR) signaling thereby inducing changes in root directional growth. Auxin signaling and polar transport components are also involved in Glc induced changes in root directional growth. Here, we provide evidence for involvement of cytokinin and ethylene signaling components in regulation of root directional growth downstream to Glc and BR. Altogether, Glc mediated change in root direction is an adaptive feature which is a result of a collaborative effort integrating phytohormonal signaling cues.
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Mazzella MA, Casal JJ, Muschietti JP, Fox AR. Hormonal networks involved in apical hook development in darkness and their response to light. FRONTIERS IN PLANT SCIENCE 2014; 5:52. [PMID: 24616725 PMCID: PMC3935338 DOI: 10.3389/fpls.2014.00052] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 02/04/2014] [Indexed: 05/19/2023]
Abstract
In darkness, the dicot seedlings produce an apical hook as result of differential cell division and extension at opposite sides of the hypocotyl. This hook protects the apical meristem from mechanical damage during seedling emergence from the soil. In darkness, gibberellins act via the DELLA-PIF (PHYTOCHROME INTERACTING FACTORs) pathway, and ethylene acts via the EIN3/EIL1 (ETHYLENE INSENSITIVE 3/EIN3 like 1)-HLS1 (HOOKLESS 1) pathway to control the asymmetric accumulation of auxin required for apical hook formation and maintenance. These core pathways form a network with multiple points of connection. Light perception by phytochromes and cryptochromes reduces the activity of PIFs and (COP1) CONSTITUTIVE PHOTOMORPHOGENIC 1-both required for hook formation in darkness-, lowers the levels of gibberellins, and triggers hook opening as a component of the switch between heterotrophic and photoautotrophic development. Apical hook opening is thus a suitable model to study the convergence of endogenous and exogenous signals on the control of cell division and cell growth.
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Affiliation(s)
- Maria A. Mazzella
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, “Dr. Héctor Torres” (INGEBI-CONICET)Buenos Aires, Argentina
- *Correspondence: Maria A. Mazzella, INGEBI, Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, “Dr. Héctor Torres”, 2490 Vuelta de Obligado, Buenos Aires, 1428, Argentina e-mail:
| | - Jorge J. Casal
- Facultad de Agronomía, Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura, Universidad de Buenos Aires and CONICETBuenos Aires, Argentina
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires-CONICETBuenos Aires, Argentina
| | - Jorge P. Muschietti
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, “Dr. Héctor Torres” (INGEBI-CONICET)Buenos Aires, Argentina
- Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos AiresBuenos Aires, Argentina
| | - Ana R. Fox
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, “Dr. Héctor Torres” (INGEBI-CONICET)Buenos Aires, Argentina
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Fonseca S, Rosado A, Vaughan-Hirsch J, Bishopp A, Chini A. Molecular locks and keys: the role of small molecules in phytohormone research. FRONTIERS IN PLANT SCIENCE 2014; 5:709. [PMID: 25566283 PMCID: PMC4269113 DOI: 10.3389/fpls.2014.00709] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Accepted: 11/26/2014] [Indexed: 05/03/2023]
Abstract
Plant adaptation, growth and development rely on the integration of many environmental and endogenous signals that collectively determine the overall plant phenotypic plasticity. Plant signaling molecules, also known as phytohormones, are fundamental to this process. These molecules act at low concentrations and regulate multiple aspects of plant fitness and development via complex signaling networks. By its nature, phytohormone research lies at the interface between chemistry and biology. Classically, the scientific community has always used synthetic phytohormones and analogs to study hormone functions and responses. However, recent advances in synthetic and combinational chemistry, have allowed a new field, plant chemical biology, to emerge and this has provided a powerful tool with which to study phytohormone function. Plant chemical biology is helping to address some of the most enduring questions in phytohormone research such as: Are there still undiscovered plant hormones? How can we identify novel signaling molecules? How can plants activate specific hormone responses in a tissue-specific manner? How can we modulate hormone responses in one developmental context without inducing detrimental effects on other processes? The chemical genomics approaches rely on the identification of small molecules modulating different biological processes and have recently identified active forms of plant hormones and molecules regulating many aspects of hormone synthesis, transport and response. We envision that the field of chemical genomics will continue to provide novel molecules able to elucidate specific aspects of hormone-mediated mechanisms. In addition, compounds blocking specific responses could uncover how complex biological responses are regulated. As we gain information about such compounds we can design small alterations to the chemical structure to further alter specificity, enhance affinity or modulate the activity of these compounds.
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Affiliation(s)
- Sandra Fonseca
- Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología- Consejo Superior de Investigaciones CientíficasMadrid, Spain
| | - Abel Rosado
- The Botany Department, University of British ColumbiaVancouver, BC, Canada
| | - John Vaughan-Hirsch
- Centre for Plant Integrative Biology, University of NottinghamNottingham, UK
| | - Anthony Bishopp
- Centre for Plant Integrative Biology, University of NottinghamNottingham, UK
| | - Andrea Chini
- Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología- Consejo Superior de Investigaciones CientíficasMadrid, Spain
- *Correspondence: Andrea Chini, Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología- Consejo Superior de Investigaciones Científicas, Campus Universidad Autónoma, C/ Darwin 3, 28049 Madrid, Spain e-mail:
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Rigal A, Ma Q, Robert S. Unraveling plant hormone signaling through the use of small molecules. FRONTIERS IN PLANT SCIENCE 2014; 5:373. [PMID: 25126092 PMCID: PMC4115670 DOI: 10.3389/fpls.2014.00373] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 07/11/2014] [Indexed: 05/03/2023]
Abstract
Plants have acquired the capacity to grow continuously and adjust their morphology in response to endogenous and external signals, leading to a high architectural plasticity. The dynamic and differential distribution of phytohormones is an essential factor in these developmental changes. Phytohormone perception is a fast but complex process modulating specific developmental reprogramming. In recent years, chemical genomics or the use of small molecules to modulate target protein function has emerged as a powerful strategy to study complex biological processes in plants such as hormone signaling. Small molecules can be applied in a conditional, dose-dependent and reversible manner, with the advantage of circumventing the limitations of lethality and functional redundancy inherent to traditional mutant screens. High-throughput screening of diverse chemical libraries has led to the identification of bioactive molecules able to induce plant hormone-related phenotypes. Characterization of the cognate targets and pathways of those molecules has allowed the identification of novel regulatory components, providing new insights into the molecular mechanisms of plant hormone signaling. An extensive structure-activity relationship (SAR) analysis of the natural phytohormones, their designed synthetic analogs and newly identified bioactive molecules has led to the determination of the structural requirements essential for their bioactivity. In this review, we will summarize the so far identified small molecules and their structural variants targeting specific phytohormone signaling pathways. We will highlight how the SAR analyses have enabled better interrogation of the molecular mechanisms of phytohormone responses. Finally, we will discuss how labeled/tagged hormone analogs can be exploited, as compelling tools to better understand hormone signaling and transport mechanisms.
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Affiliation(s)
| | | | - Stéphanie Robert
- *Correspondence: Stéphanie Robert, Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, 901 83 Umeå, Sweden e-mail:
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Tresch S. Strategies and future trends to identify the mode of action of phytotoxic compounds. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2013; 212:60-71. [PMID: 24094055 DOI: 10.1016/j.plantsci.2013.08.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 08/15/2013] [Accepted: 08/16/2013] [Indexed: 05/09/2023]
Abstract
Small molecules affecting plant processes have been widely used as probes to study basic physiology. In agricultural practices some of these molecules have served as herbicides or plant growth regulators. Historically, most of the compounds were identified in large screens by the agrochemical industry, but also as phytoactive natural products. More recently, novel phytoactive compounds originated from academic research by chemical screens performed to induce specific phenotypes of interest. In the present review different approaches were evaluated for the identification of the mode of action (MoA) of phytoactive compounds. Based on the methodologies used for MoA identification, three approaches are differentiated: a phenotyping approach, an approach based on a genetic screen and a biochemical screening approach. Target sites of compounds targeting primary or secondary metabolism were identified most successfully with a phenotyping approach. Target sites for compounds that influence cell structure, such as cell wall biosynthesis or the cytoskeleton, or compounds that interact with the hormone system, were in most cases discovered by using a genetic approach. Examples showing the strengths and weaknesses of the different approaches are discussed in detail. Additionally, new techniques that could contribute to future MoA identification projects are reviewed. In particular, next-generation sequencing techniques may be used for the fast-forward mapping of mutants identified in genetic screens. Finally, a revised three-tiered approach for the MoA identification of phytoactive compounds is proposed. The approach consists of a 1st tier, which addresses compound stability, uniformity of effects in different species, general cytotoxicity and the effect on common processes such as transcription and translation. Advanced studies based on these findings initiate the 2nd tier MoA characterization, either with further phenotypic characterization, starting a genetic screen or establishing a biochemical screen. At the 3rd tier, enzyme assays or protein affinity studies should show the activity of the compound on the hypothesized target and should associate the in vitro effects with the in vivo profile of the compound.
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Affiliation(s)
- Stefan Tresch
- BASF SE, Crop Protection, Speyerer Str. 2, 67117 Limburgerhof, Germany.
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Chen IJ, Lo WS, Chuang JY, Cheuh CM, Fan YS, Lin LC, Wu SJ, Wang LC. A chemical genetics approach reveals a role of brassinolide and cellulose synthase in hypocotyl elongation of etiolated Arabidopsis seedlings. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2013; 209:46-57. [PMID: 23759102 DOI: 10.1016/j.plantsci.2013.04.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Revised: 04/17/2013] [Accepted: 04/18/2013] [Indexed: 05/09/2023]
Abstract
The development of juvenile seedlings after germination is critical for the initial establishment of reproductive plants. Ethylene plays a pivotal role in the growth of seedlings under light or dark during early development. Previously, we identified small molecules sharing a quinazolinone backbone that suppressed the constitutive triple response phenotype in dark-grown eto1-4 seedlings. We designated these small molecules as ACSinhibitor quinazolinones (acsinones), which were uncompetitive inhibitors of 1-aminocyclopropane-1-carboxylic acid synthase. To explore the additional roles of acsinones in plants, we screened and identified 19 Arabidopsis mutants with reduced sensitivity to acsinone7303, which were collectively named revert to eto1 (ret) because of their recovery of the eto1 phenotype. A map-based cloning approach revealed that CELLULOSE SYNTHASE6 (CESA6) and DE-ETIOLATED2 (DET2) were mutated in ret8 (cesa6(ret8);eto1-4) and ret41 (det2(ret41);eto1-5), respectively. Etiolated seedlings of both ret8 and ret41 exhibit short hypocotyls and roots. Ethylene levels were similar in etiolated cesa6(ret8) and det2-1 and in eto1 mutants treated with acsinone7303. Chemical inhibitors of ethylene biosynthesis and perception did not significantly suppress the etiolated phenotype of cesa6(ret8) and det2(ret41). However, together with eto1, cesa6(ret8) and det2(ret41) exhibited an enhanced phenotype in the hypocotyls and apical hooks of etiolated seedlings. These results confirm that, in addition to ethylene, cellulose synthesis and brassinolides can independently contribute to modulate hypocotyl development in young seedlings.
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Affiliation(s)
- I-Ju Chen
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 115, Taiwan, ROC
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Polko JK, Pierik R, van Zanten M, Tarkowská D, Strnad M, Voesenek LACJ, Peeters AJM. Ethylene promotes hyponastic growth through interaction with ROTUNDIFOLIA3/CYP90C1 in Arabidopsis. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:613-24. [PMID: 23264517 PMCID: PMC3542051 DOI: 10.1093/jxb/ers356] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Upward leaf movement, called hyponastic growth, is employed by plants to cope with adverse environmental conditions. Ethylene is a key regulator of this process and, in Arabidopsis thaliana, hyponasty is induced by this phytohormone via promotion of epidermal cell expansion in a proximal zone of the abaxial side of the petiole. ROTUNDIFOLIA3/CYP90C1 encodes an enzyme which was shown to catalyse C-23 hydroxylation of several brassinosteroids (BRs) - phytohormones involved in, for example, organ growth, cell expansion, cell division, and responses to abiotic and biotic stresses. This study tested the interaction between ethylene and BRs in regulating hyponastic growth. A mutant isolated in a forward genetic screen, with reduced hyponastic response to ethylene treatment, was allelic to rot3. The cause of the reduced hyponastic growth in this mutant was examined by studying ethylene-BR interaction during local cell expansion, pharmacological inhibition of BR synthesis and ethylene effects on transcription of BR-related genes. This work demonstrates that rot3 mutants are impaired in local cell expansion driving hyponasty. Moreover, the inhibition of BR biosynthesis reduces ethylene-induced hyponastic growth and ethylene increases sensitivity to BR in promoting cell elongation in Arabidopsis hypocotyls. Together, the results show that ROT3 modulates ethylene-induced petiole movement and that this function is likely BR related.
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Affiliation(s)
- Joanna K. Polko
- Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Ronald Pierik
- Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Martijn van Zanten
- Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
- Molecular Plant Physiology, Institute of Environmental Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Danuše Tarkowská
- Laboratory of Growth Regulators, Faculty of Science, Palacký University and Institute of Experimental Botany AS CR, v.v.i., Šlechtitelů 11, CZ-783 71 Olomouc, Czech Republic
| | - Miroslav Strnad
- Laboratory of Growth Regulators, Faculty of Science, Palacký University and Institute of Experimental Botany AS CR, v.v.i., Šlechtitelů 11, CZ-783 71 Olomouc, Czech Republic
- Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 21, CZ-783 71 Olomouc, Czech Republic
| | - Laurentius A. C. J. Voesenek
- Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Anton J. M. Peeters
- Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
- Institute of Education, Department of Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
- * To whom correspondence should be addressed. E-mail:
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30
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Kombrink E. Chemical and genetic exploration of jasmonate biosynthesis and signaling paths. PLANTA 2012; 236:1351-66. [PMID: 23011567 DOI: 10.1007/s00425-012-1705-z] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Accepted: 06/27/2012] [Indexed: 05/03/2023]
Abstract
Jasmonates are lipid-derived compounds that act as signals in plant stress responses and developmental processes. Enzymes participating in biosynthesis of jasmonic acid (JA) and components of JA signaling have been extensively characterized by biochemical and molecular-genetic tools. Mutants have helped to define the pathway for synthesis of jasmonoyl-L-isoleucine (JA-Ile), the bioactive form of JA, and to identify the F-box protein COI1 as central regulatory unit. Details on the molecular mechanism of JA signaling were recently unraveled by the discovery of JAZ proteins that together with the adaptor protein NINJA and the general co-repressor TOPLESS form a transcriptional repressor complex. The current model of JA perception and signaling implies the SCF(COI1) complex operating as E3 ubiquitin ligase that upon binding of JA-Ile targets JAZ proteins for degradation by the 26S proteasome pathway, thereby allowing MYC2 and other transcription factors to activate gene expression. Chemical strategies, as integral part of jasmonate research, have helped the establishment of structure-activity relationships and the discovery of (+)-7-iso-JA-L-Ile as the major bioactive form of the hormone. The transient nature of its accumulation highlights the need to understand catabolism and inactivation of JA-Ile and recent studies indicate that oxidation of JA-Ile by cytochrome P450 monooxygenase is the major mechanism for turning JA signaling off. Plants contain numerous JA metabolites, which may have pronounced and differential bioactivity. A major challenge in the field of plant lipid signaling is to identify the cognate receptors and modes of action of these bioactive jasmonates/oxylipins.
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Affiliation(s)
- Erich Kombrink
- Chemical Biology Laboratory, Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, 50829, Köln, Germany.
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31
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Zhao B, Li J. Regulation of brassinosteroid biosynthesis and inactivation. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2012; 54:746-59. [PMID: 22963251 DOI: 10.1111/j.1744-7909.2012.01168.x] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Brassinosteroids (BRs) are a group of naturally-occurring steroidal phytohormones playing fundamental roles during normal plant growth and development. Using a combination of experimental approaches, including analytical chemistry, genetics, and biochemistry, the major BR biosynthetic pathway has been largely elucidated. The least-understood knowledge in the BR research field is probably the molecular mechanisms controlling the bioactive levels of BRs in response to various developmental and environmental cues. In this review, we focus our discussion on a recently-proposed, 8-step predominant BR biosynthetic pathway, several newly-identified transcription factors regulating the expression of key enzymes that catalyze BR biosynthesis, and up-to-date information about the mechanisms that plants use to inactivate unnecessary BRs.
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Affiliation(s)
- Baolin Zhao
- Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
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32
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Kutschera U, Wang ZY. Brassinosteroid action in flowering plants: a Darwinian perspective. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:3511-22. [PMID: 22547659 PMCID: PMC3388831 DOI: 10.1093/jxb/ers065] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 02/06/2012] [Accepted: 02/08/2012] [Indexed: 05/04/2023]
Abstract
The year 2012 marks the 150th anniversary of the publication of Charles Darwin's first botanical book, on the fertilization of orchids (1862), wherein he described pollen grains and outlined his evolutionary principles with respect to plant research. Five decades later, the growth-promoting effect of extracts of Orchid pollen on coleoptile elongation was documented. These studies led to the discovery of a new class of phytohormones, the brassinosteroids (BRs) that were isolated from rapeseed (Brassica napus) pollen. These growth-promoting steroids, which regulate height, fertility, and seed-filling in crop plants such as rice (Oryza sativa), also induce stress- and disease resistance in green algae and angiosperms. The origin and current status of BR-research is described here, with reference to BR-action and -signal transduction, and it is shown that modern high-yield rice varieties with erect leaves are deficient in endogenous BRs. Since brassinosteroids induce pathogen resistance in rice plants and hence can suppress rice blast- and bacterial blight-diseases, genetic manipulation of BR-biosynthesis or -perception may be a means to increase crop production. Basic research on BR activity in plants, such as Arabidopsis and rice, has the potential to increase crop yields further as part of a 21th century 'green biotech-revolution' that can be traced back to Darwin's classical breeding experiments. It is concluded that 'Nothing in brassinosteroid research makes sense except in the light of Darwinian evolution' and the value of basic science is highlighted, with reference to the genetic engineering of better food crops that may become resistant to a variety of plant diseases.
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Affiliation(s)
- Ulrich Kutschera
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305, USA.
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Xin Z, Yu Z, Erb M, Turlings TCJ, Wang B, Qi J, Liu S, Lou Y. The broad-leaf herbicide 2,4-dichlorophenoxyacetic acid turns rice into a living trap for a major insect pest and a parasitic wasp. THE NEW PHYTOLOGIST 2012; 194:498-510. [PMID: 22313362 DOI: 10.1111/j.1469-8137.2012.04057.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: 05/31/2023]
Abstract
Synthetic chemical elicitors of plant defense have been touted as a powerful means for sustainable crop protection. Yet, they have never been successfully applied to control insect pests in the field. We developed a high-throughput chemical genetics screening system based on a herbivore-induced linalool synthase promoter fused to a β-glucuronidase (GUS) reporter construct to test synthetic compounds for their potential to induce rice defenses. We identified 2,4-dichlorophenoxyacetic acid (2,4-D), an auxin homolog and widely used herbicide in monocotyledonous crops, as a potent elicitor of rice defenses. Low doses of 2,4-D induced a strong defensive reaction upstream of the jasmonic acid and ethylene pathways, resulting in a marked increase in trypsin proteinase inhibitor activity and volatile production. Induced plants were more resistant to the striped stem borer Chilo suppressalis, but became highly attractive to the brown planthopper Nilaparvata lugens and its main egg parasitoid Anagrus nilaparvatae. In a field experiment, 2,4-D application turned rice plants into living traps for N. lugens by attracting parasitoids. Our findings demonstrate the potential of auxin homologs as defensive signals and show the potential of the herbicide to turn rice into a selective catch crop for an economically important pest.
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Affiliation(s)
- Zhaojun Xin
- National Key Laboratory of Rice Biology, Institute of Insect Science, Zhejiang University, Hangzhou 310029, China
| | - Zhaonan Yu
- National Key Laboratory of Rice Biology, Institute of Insect Science, Zhejiang University, Hangzhou 310029, China
| | - Matthias Erb
- Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, 07745, Jena, Germany
| | - Ted C J Turlings
- Laboratory of Fundamental and Applied Research in Chemical Ecology, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, CP158, CH-2009, Neuchâtel, Switzerland
| | - Baohui Wang
- National Key Laboratory of Rice Biology, Institute of Insect Science, Zhejiang University, Hangzhou 310029, China
| | - Jinfeng Qi
- National Key Laboratory of Rice Biology, Institute of Insect Science, Zhejiang University, Hangzhou 310029, China
| | - Shengning Liu
- National Key Laboratory of Rice Biology, Institute of Insect Science, Zhejiang University, Hangzhou 310029, China
| | - Yonggen Lou
- National Key Laboratory of Rice Biology, Institute of Insect Science, Zhejiang University, Hangzhou 310029, China
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Hicks GR, Raikhel NV. Small molecules present large opportunities in plant biology. ANNUAL REVIEW OF PLANT BIOLOGY 2012; 63:261-82. [PMID: 22404475 DOI: 10.1146/annurev-arplant-042811-105456] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Since the introduction of chemical genomics to plant biology as a tool for basic research, the field has advanced significantly. There are now examples of important basic discoveries that demonstrate the power and untapped potential of this approach. Given the combination of protein and small-molecule complexity, new phenotypes can be described through the perturbation of cellular functions that can be linked to growth and developmental phenotypes. There are now clear examples of overcoming functional redundancy in plants to dissect molecular mechanisms or critical pathways such as hormone signaling and dynamic intracellular processes. Owing to ongoing advances, including more sophisticated high-content screening and rapid approaches for target identification, the field is beginning to move forward. However, there are also challenges to improve automation, imaging, and analysis and provide chemical biology resources to the broader plant biology community.
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Affiliation(s)
- Glenn R Hicks
- Center for Plant Cell Biology, Institute for Integrative Genome Biology, Department of Botany and Plant Sciences, University of California, Riverside, CA 92521, USA.
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35
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Shakirova FM, Avalbaev AM, Bezrukova MV, Fatkhutdinova RA, Maslennikova DR, Yuldashev RA, Allagulova CR, Lastochkina OV. Hormonal Intermediates in the Protective Action of Exogenous Phytohormones in Wheat Plants Under Salinity. PHYTOHORMONES AND ABIOTIC STRESS TOLERANCE IN PLANTS 2012:185-228. [DOI: 10.1007/978-3-642-25829-9_9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/23/2023]
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36
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Codreanu MC, Audenaert D, Nguyen L, Beeckman T, Russinova E. Small-molecule dissection of brassinosteroid signaling. Methods Mol Biol 2012; 876:95-106. [PMID: 22576088 DOI: 10.1007/978-1-61779-809-2_7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The growth-promoting hormones, the brassinosteroids (BRs), are perceived at the plant cell surface by receptor kinases that transduce the signal to the nucleus by an intracellular cascade of phosphorylation-mediated protein-protein interactions. BR signaling is also regulated by the plant endocytic machinery because the increased endosomal localization of the BR receptor enhances the BR responses. Chemical genetics is a powerful approach to identify new components in redundant signaling networks and to characterize highly dynamic processes, such as endocytosis. Here, we describe a screen in Arabidopsis thaliana seedlings for small molecules that affect hypocotyl elongation under continuous light conditions, indicative for an effect on BR responses. The compounds identified in this screen were used to dissect endomembrane trafficking of the BR receptor, BR INSENSITIVE1, a process that is essential for BR signal transduction.
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37
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Doğramacı M, Horvath DP, Christoffers MJ, Anderson JV. Dehydration and vernalization treatments identify overlapping molecular networks impacting endodormancy maintenance in leafy spurge crown buds. Funct Integr Genomics 2011; 11:611-26. [PMID: 21789635 DOI: 10.1007/s10142-011-0239-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2011] [Revised: 06/29/2011] [Accepted: 07/03/2011] [Indexed: 11/30/2022]
Abstract
Leafy spurge (Euphorbia esula L.) is a herbaceous perennial weed that reproduces vegetatively from an abundance of underground adventitious buds (UABs), which undergo well-defined phases of seasonal dormancy (para-, endo-, and ecodormancy). In this study, the effects of dehydration stress on vegetative growth and flowering potential from endodormant UABs of leafy spurge was monitored. Further, microarray analysis was used to identify critical signaling pathways of transcriptome profiles associated with endodormancy maintenance in UABs. Surprisingly, only 3-day of dehydration stress is required to break the endodormant phase in UABs; however, the dehydration-stress treatment did not induce flowering. Previous studies have shown that prolonged cold treatment of UABs breaks endodormancy and induces a vernalization response leading to flowering. Thus, in this study, comparing transcriptome data from UABs exposed to short-term dehydration and vernalization provided a unique approach to identify overlapping molecular mechanisms involved in endodormancy maintenance and floral competence. Analysis of transcriptome data associated with breaking endodormancy by both environmental treatments identified LEC1, PHOTOSYSTEM I RC, and brassinosteroids as common central hubs of upregulated genes, while DREB1A, CBF2, GPA1, MYC2, bHLH, BZIP, and flavonoids were identified as common central hubs of downregulated genes. The majority of over-represented gene sets common to breaking endodormancy by dehydration stress and vernalization were downregulated and included pathways involved in hormone signaling, chromatin modification, and circadian rhythm. Additionally, the over-represented gene sets highlighted pathways involved in starch and sugar degradation and biogenesis of carbon skeletons, suggesting a high metabolic activity is necessary during the endodormant phase. The data presented in this study helped to refine our previous model for dormancy regulation.
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Affiliation(s)
- Münevver Doğramacı
- Biosciences Research Laboratory, USDA-Agricultural Research Service, 1605 Albrecht Blvd. N., Fargo, ND 58102-2765, USA
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Sun Y, Fan XY, Cao DM, Tang W, He K, Zhu JY, He JX, Bai MY, Zhu S, Oh E, Patil S, Kim TW, Ji H, Wong WH, Rhee SY, Wang ZY. Integration of brassinosteroid signal transduction with the transcription network for plant growth regulation in Arabidopsis. Dev Cell 2010; 19:765-77. [PMID: 21074725 DOI: 10.1016/j.devcel.2010.10.010] [Citation(s) in RCA: 619] [Impact Index Per Article: 44.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 09/15/2010] [Accepted: 10/04/2010] [Indexed: 11/16/2022]
Abstract
Brassinosteroids (BRs) regulate a wide range of developmental and physiological processes in plants through a receptor-kinase signaling pathway that controls the BZR transcription factors. Here, we use transcript profiling and chromatin-immunoprecipitation microarray (ChIP-chip) experiments to identify 953 BR-regulated BZR1 target (BRBT) genes. Functional studies of selected BRBTs further demonstrate roles in BR promotion of cell elongation. The BRBT genes reveal numerous molecular links between the BR-signaling pathway and downstream components involved in developmental and physiological processes. Furthermore, the results reveal extensive crosstalk between BR and other hormonal and light-signaling pathways at multiple levels. For example, BZR1 not only controls the expression of many signaling components of other hormonal and light pathways but also coregulates common target genes with light-signaling transcription factors. Our results provide a genomic map of steroid hormone actions in plants that reveals a regulatory network that integrates hormonal and light-signaling pathways for plant growth regulation.
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Affiliation(s)
- Yu Sun
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA
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39
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Deslauriers SD, Larsen PB. FERONIA is a key modulator of brassinosteroid and ethylene responsiveness in Arabidopsis hypocotyls. MOLECULAR PLANT 2010; 3:626-40. [PMID: 20400488 DOI: 10.1093/mp/ssq015] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Ethylene signaling is a complex pathway that has been intensively analyzed partly due to its importance to the manifestation of horticultural phenomena, including fruit ripening and tissue senescence. In order to further our understanding of how this pathway is regulated, a screen for Arabidopsis mutants with increased ethylene response was conducted. From this, a mutant was identified as having a dark-grown hypocotyl that is indistinguishable from Col-0 wt in the presence of the ethylene perception inhibitor AgNO₃, yet has extreme responsiveness to even low levels of ethylene. Map-based cloning of the mutation revealed a T-DNA insertion in the coding sequence of the receptor-like kinase FERONIA, which is required for normal pollen tube reception and cell elongation in a currently unknown capacity. In contrast to a previous report, analysis of our feronia knockout mutant shows it also has altered responsiveness to brassinosteroids, with etiolated fer-2 seedlings being partially brassinosteroid insensitive with regard to promotion of hypocotyl elongation. Our results indicate that FERONIA-dependent brassinosteroid response serves to antagonize the effect of ethylene on hypocotyl growth of etiolated seedlings, with loss of proper brassinosteroid signaling disrupting this balance and leading to a greater impact of ethylene on hypocotyl shortening.
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Affiliation(s)
- Stephen D Deslauriers
- Department of Biochemistry, University of California-Riverside, Riverside, CA 92521, USA
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40
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Serrano M, Hubert DA, Dangl JL, Schulze-Lefert P, Kombrink E. A chemical screen for suppressors of the avrRpm1-RPM1-dependent hypersensitive cell death response in Arabidopsis thaliana. PLANTA 2010; 231:1013-23. [PMID: 20140739 PMCID: PMC2840663 DOI: 10.1007/s00425-010-1105-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2009] [Accepted: 01/18/2010] [Indexed: 05/20/2023]
Abstract
Arabidopsis thaliana RPM1 encodes an intracellular immune sensor that conditions disease resistance to Pseudomonas syringae expressing the type III effector protein AvrRpm1. Conditional expression of this type III effector in a transgenic line carrying avrRpm1 under the control of a steroid-inducible promoter results in RPM1-dependent cell death that resembles the cell death response of the incompatible RPM1-avrRpm1 plant-bacterium interaction. This line was previously used in a genetic screen, which revealed two genes that likely function in the folding of pre-activation RPM1. We established a chemical screen for small molecules that suppress steroid-inducible and RPM1-avrRpm1-dependent cell death in Arabidopsis seedlings. Screening of a library comprising 6,800 compounds of natural origin identified two trichothecene-type mycotoxins, 4,15-diacetoxyscirpenol (DAS) and neosolaniol (NEO), which are synthesized by Fusarium and other fungal species. However, protein blot analysis revealed that DAS and NEO inhibit AvrRpm1 synthesis rather than suppress RPM1-mediated responses. This inhibition of translational activity likely explains the survival of the seedlings under screening conditions. Likewise, flg22-induced defense responses are also impaired at the translational, but not the transcriptional, level by DAS or NEO. Unexpectedly, both compounds not only prevented AvrRpm1 synthesis, but rather caused an apparent hyper-accumulation of RPM1 and HSP70. The hyper-accumulation phenotype is likely unrelated to the ribotoxic function of DAS and NEO and could be due to an inhibitory activity on the proteolytic machinery of Arabidopsis or elicitor-like activities of type A trichothecenes.
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Affiliation(s)
- Mario Serrano
- Department of Plant-Microbe Interactions, Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, 50829 Cologne, Germany
- Present Address: Department of Biology, University of Fribourg, Chemin du Musée 10, 1700 Fribourg, Switzerland
| | - David A. Hubert
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599-3280 USA
| | - Jeffery L. Dangl
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599-3280 USA
| | - Paul Schulze-Lefert
- Department of Plant-Microbe Interactions, Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, 50829 Cologne, Germany
| | - Erich Kombrink
- Department of Plant-Microbe Interactions, Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, 50829 Cologne, Germany
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41
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Mills-Lujan K, Deom CM. Geminivirus C4 protein alters Arabidopsis development. PROTOPLASMA 2010; 239:95-110. [PMID: 20091067 DOI: 10.1007/s00709-009-0086-z] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Accepted: 10/28/2009] [Indexed: 05/21/2023]
Abstract
The C4 protein of beet curly top virus [BCTV-B (US:Log:76)] induces hyperplasia in infected phloem tissue and tumorigenic growths in transgenic plants. The protein offers an excellent model for studying cell cycle control, cell differentiation, and plant development. To investigate the role of the C4 protein in plant development, transgenic Arabidopsis thaliana plants were generated in which the C4 transgene was expressed under the control of an inducible promoter. A detailed analysis of the developmental changes that occur in cotyledons and hypocotyls of seedlings expressing the C4 transgene showed extensive cell division in all tissues types examined, radically altered tissue layer organization, and the absence of a clearly defined vascular system. Induced seedlings failed to develop true leaves, lateral roots, and shoot and root apical meristems, as well as vascular tissue. Specialized epidermis structures, such as stomata and root hairs, were either absent or developmentally impaired in seedlings that expressed C4 protein. Exogenous application of brassinosteroid and abscisic acid weakly rescued the C4-induced phenotype, while induced seedlings were hypersensitive to gibberellic acid and kinetin. These results indicate that ectopic expression of the BCTV C4 protein in A. thaliana drastically alters plant development, possibly through the disruption of multiple hormonal pathways.
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Affiliation(s)
- Katherine Mills-Lujan
- Department of Plant Pathology, The University of Georgia, Athens, GA 30602-7274, USA
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Tóth R, van der Hoorn RAL. Emerging principles in plant chemical genetics. TRENDS IN PLANT SCIENCE 2010; 15:81-8. [PMID: 20036182 DOI: 10.1016/j.tplants.2009.11.005] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Revised: 11/19/2009] [Accepted: 11/22/2009] [Indexed: 05/04/2023]
Abstract
Chemical genetics is a powerful new discipline in plant science. Bioactive small molecules can be used to identify novel signalling nodes and unravel redundant networks. Observations made so far have revealed a series of principles in plant chemical genetics. These principles concern compound properties, such as bioactivation and bioavailability; and valuable approaches, like the use of derivatives and transcriptomics and successful ways of target identification. Together, these principles explain why the choice of the chemical library is important and instruct the design of future chemical genetic screens.
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Affiliation(s)
- Réka Tóth
- Department of Plant Developmental Biology, Max Planck Institute for Plant Breeding Research, Carl-von-Linne Weg 10, 50829 Cologne, Germany.
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43
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Avalbaev AM, Yuldashev RA, Fatkhutdinova RA, Urusov FA, Safutdinova YV, Shakirova FM. The influence of 24-epibrassidinolide on the hormonal status of wheat plants under sodium chloride. APPL BIOCHEM MICRO+ 2010. [DOI: 10.1134/s0003683810010175] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Zhang S, Wei Y, Lu Y, Wang X. Mechanisms of brassinosteroids interacting with multiple hormones. PLANT SIGNALING & BEHAVIOR 2009; 4:1117-20. [PMID: 20514225 PMCID: PMC2819435 DOI: 10.4161/psb.4.12.9903] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2009] [Accepted: 08/25/2009] [Indexed: 05/18/2023]
Abstract
Various environmental and internal cues play essential roles in regulating diverse aspects of plant growth and development. Phytohormones usually coordinate multiple stimuli to directly regulate multiple developmental programs. Recent studies have provided progresses into the complexity of their cross talk. Particularly, the signaling pathways of various phytohormones have been revealed, leading to the discovery of the mechanisms of the interplay among different hormone signaling pathways. This review focuses on the recent advances of the signaling cross-talk between brassinosteroids and other hormones, including abscisic acid, auxin, gibberellins, ethylene and jasmonate.
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Affiliation(s)
- Shanshan Zhang
- State Key Laboratory of Genetic Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, China
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45
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Ren C, Han C, Peng W, Huang Y, Peng Z, Xiong X, Zhu Q, Gao B, Xie D. A leaky mutation in DWARF4 reveals an antagonistic role of brassinosteroid in the inhibition of root growth by jasmonate in Arabidopsis. PLANT PHYSIOLOGY 2009; 151:1412-20. [PMID: 19741050 PMCID: PMC2773060 DOI: 10.1104/pp.109.140202] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2009] [Accepted: 09/01/2009] [Indexed: 05/18/2023]
Abstract
The F-box protein CORONATINE INSENSITIVE1 (COI1) plays a central role in jasmonate (JA) signaling and is required for all JA responses in Arabidopsis (Arabidopsis thaliana). To dissect JA signal transduction, we isolated the partially suppressing coi1 (psc1) mutant, which partially suppressed coi1 insensitivity to JA inhibition of root growth. The psc1 mutant partially restored JA sensitivity in coi1-2 background and displayed JA hypersensitivity in wild-type COI1 background. Genetic mapping, sequence analysis, and complementation tests revealed that psc1 is a leaky mutation of DWARF4 (DWF4) that encodes a key enzyme in brassinosteroid (BR) biosynthesis. Physiological analysis showed that an application of exogenous BR eliminated the partial restoration of JA sensitivity by psc1 in coi1-2 background and the JA hypersensitivity of psc1 in wild-type COI1 background. Exogenous BR also attenuated JA inhibition of root growth in the wild type. In addition, the expression of DWF4 was inhibited by JA, and this inhibition was dependent on COI1. These results indicate that (1) BR is involved in JA signaling and negatively regulates JA inhibition of root growth, and (2) the DWF4 is down-regulated by JA and is located downstream of COI1 in the JA-signaling pathway.
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46
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Song LI, Zhou XY, Li LI, Xue LJ, Yang XI, Xue HW. Genome-wide analysis revealed the complex regulatory network of brassinosteroid effects in photomorphogenesis. MOLECULAR PLANT 2009; 2:755-772. [PMID: 19825654 DOI: 10.1093/mp/ssp039] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Light and brassinosteroids (BRs) have been proved to be crucial in regulating plant growth and development; however, the mechanism of how they synergistically function is still largely unknown. To explore the underlying mechanisms in photomorphogenesis, genome-wide analyses were carried out through examining the gene expressions of the dark-grown WT or BR biosynthesis-defective mutant det2 seedlings in the presence of light stimuli or exogenous Brassinolide (BL). Results showed that BR deficiency stimulates, while BL treatment suppresses, the expressions of light-responsive genes and photomorphogenesis, confirming the negative effects of BR in photomorphogenesis. This is consistent with the specific effects of BR on the expression of genes involved in cell wall modification, cellular metabolism and energy utilization during dark-light transition. Further analysis revealed that hormone biosynthesis and signaling-related genes, especially those of auxin, were altered under BL treatment or light stimuli, indicating that BR may modulate photomorphogenesis through synergetic regulation with other hormones. Additionally, suppressed ubiquitin-cycle pathway during light-dark transition hinted the presence of a complicated network among light, hormone, and protein degradation. The study provides the direct evidence of BR effects in photomorphogenesis and identified the genes involved in BR and light signaling pathway, which will help to elucidate the molecular mechanism of plant photomorphogenesis.
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MESH Headings
- Arabidopsis/drug effects
- Arabidopsis/genetics
- Arabidopsis/growth & development
- Arabidopsis/metabolism
- Arabidopsis/radiation effects
- Arabidopsis Proteins/genetics
- Arabidopsis Proteins/physiology
- Brassinosteroids
- Cholestanols/metabolism
- Cholestanols/pharmacology
- Chromatin Immunoprecipitation
- Cluster Analysis
- Gene Expression Regulation, Plant/drug effects
- Gene Expression Regulation, Plant/radiation effects
- Genome, Plant/genetics
- Genome-Wide Association Study
- Light
- Morphogenesis/drug effects
- Morphogenesis/radiation effects
- Plants, Genetically Modified/drug effects
- Plants, Genetically Modified/genetics
- Plants, Genetically Modified/growth & development
- Plants, Genetically Modified/radiation effects
- Promoter Regions, Genetic
- Reverse Transcriptase Polymerase Chain Reaction
- Signal Transduction/drug effects
- Signal Transduction/radiation effects
- Steroids, Heterocyclic/metabolism
- Steroids, Heterocyclic/pharmacology
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Affiliation(s)
- L I Song
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, 200032 Shanghai, China
| | - Xiao-Yi Zhou
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, 200032 Shanghai, China
| | - L I Li
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, 200032 Shanghai, China
| | - Liang-Jiao Xue
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, 200032 Shanghai, China
| | - X I Yang
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, 200032 Shanghai, China
| | - Hong-Wei Xue
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, 200032 Shanghai, China.
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47
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Alabadí D, Blázquez MA. Molecular interactions between light and hormone signaling to control plant growth. PLANT MOLECULAR BIOLOGY 2009; 69:409-17. [PMID: 18797998 DOI: 10.1007/s11103-008-9400-y] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2008] [Accepted: 09/04/2008] [Indexed: 05/22/2023]
Abstract
As sessile organisms, plants modulate their growth rate and development according to the continuous variation in the conditions of their surrounding environment, an ability referred to as plasticity. This ability relies on a web of interactions between signaling pathways triggered by endogenous and environmental cues. How changes in environmental factors are interpreted by the plant in terms of developmental or growth cues or, in other words, how they contribute to plant plasticity is a current, major question in plant biology. Light stands out among the environmental factors that shape plant development. Plants have evolved systems that allow them to monitor both quantitative and qualitative differences in the light that they perceive, that render important changes in their growth habit. In this review we focus on recent findings about how information from this environmental cue is integrated during de-etiolation and in the shade-avoidance syndrome, and modulated by several hormone pathways-the endogenous cues. In some cases the interaction between a hormone and the light signaling pathways is reciprocal, as is the case of the gibberellin pathway, whereas in other cases hormone pathways act downstream of the environmental cue to regulate growth. Moreover, the circadian clock adds an additional layer of regulation, which has been proposed to integrate the information provided by light with that provided by hormone pathways, to regulate daily growth.
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Affiliation(s)
- David Alabadí
- Instituto de Biología Molecular y Celular de Plantas (UPV-CSIC), Universidad Politécnica de Valencia, Avda de los Naranjos s/n, 46022 Valencia, Spain
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48
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Robert S, Raikhel NV, Hicks GR. Powerful partners: Arabidopsis and chemical genomics. THE ARABIDOPSIS BOOK 2009; 7:e0109. [PMID: 22303245 PMCID: PMC3243329 DOI: 10.1199/tab.0109] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Chemical genomics (i.e. genomics scale chemical genetics) approaches capitalize on the ability of low molecular mass molecules to modify biological processes. Such molecules are used to modify the activity of a protein or a pathway in a manner that it is tunable and reversible. Bioactive chemicals resulting from forward or reverse chemical screens can be useful in understanding and dissecting complex biological processes due to the essentially limitless variation in structure and activities inherent in chemical space. A major advantage of this approach as a powerful addition to conventional plant genetics is the fact that chemical genomics can address loss-of-function lethality and redundancy. Furthermore, the ability of chemicals to be added at will and to act quickly can permit the study of processes that are highly dynamic such as endomembrane trafficking. An important aspect of utilizing small molecules effectively is to characterize bioactive chemicals in detail including an understanding of structure-activity relationships and the identification of active and inactive analogs. Bioactive chemicals can be useful as reagents to probe biological pathways directly. However, the identification of cognate targets and their pathways is also informative and can be achieved by screens for genetic resistance or hypersensitivity in Arabidopsis thaliana or other organisms from which the results can be translated to plants. In addition, there are approaches utilizing "tagged" chemical libraries that possess reactive moieties permitting the immobilization of active compounds. This opens the possibility for biochemical purification of putative cognate targets. We will review approaches to screen for bioactive chemicals that affect biological processes in Arabidopsis and provide several examples of the power and challenges inherent in this new approach in plant biology.
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Affiliation(s)
- Stéphanie Robert
- Center for Plant Cell Biology & Department of Botany and Plant Sciences, University of California, Riverside, CA 92521
- Current address: VIB Department of Plant Systems Biology, University of Ghent, 9052 Ghent, Belgium
| | - Natasha V. Raikhel
- Center for Plant Cell Biology & Department of Botany and Plant Sciences, University of California, Riverside, CA 92521
| | - Glenn R. Hicks
- Center for Plant Cell Biology & Department of Botany and Plant Sciences, University of California, Riverside, CA 92521
- Address correspondence to
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