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Yu S, Gong L, Han YC, Yang L, Li J, Hoffmann AA, Luo GH, Yuan GR, Fang JC, Ji R. Oral secretions from striped stem borer (Chilo suppressalis) induce defenses in rice. PEST MANAGEMENT SCIENCE 2024. [PMID: 39152725 DOI: 10.1002/ps.8376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2024] [Revised: 07/25/2024] [Accepted: 08/02/2024] [Indexed: 08/19/2024]
Abstract
BACKGROUND The striped stem borer (SSB, Chilo suppressalis) is one of the most destructive insect pests on rice. As a chewing insect, SSB larval feeding causes a dramatic increase in rice defense responses. However, the effects of oral secretions (OSs) during SSB feeding on rice defense remain largely unexplored. RESULTS In this study, based on transcriptome analysis results, treatment with SSB OSs regulated the expression of genes involved in the plant defense-related pathways of calcium, mitogen-activated protein kinases, reactive oxygen species, jasmonic acid (JA), herbivore-induced plant volatiles (HIPVs), and protease inhibitors. Unsurprisingly, treatment with SSB OSs elicited the accumulation of JA and JA-isoleucine in rice. The defense mechanisms activated by the cascade not only induced the expression of trypsin inhibitors, inhibiting the normal growth of SSB larvae but also induced HIPVs emission, rendering rice attractive to a common larval parasitoid. High-throughput proteome sequencing of SSB OSs led to 534 proteins being identified and 343 proteins with two or more unique peptides being detected. CONCLUSION The study demonstrates that SSB OSs trigger both direct and indirect defense mechanisms in rice, akin to the effects of SSB feeding. It identifies specific proteins in SSB OSs that may influence the interactions between SSB and rice during feeding, providing valuable insights for effectors research. © 2024 Society of Chemical Industry.
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Affiliation(s)
- Shan Yu
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Jiangsu Key Laboratory for Food and Safety (State Key Laboratory Cultivation Base of Ministry of Science and Technology), Nanjing, China
| | - Lei Gong
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Jiangsu Key Laboratory for Food and Safety (State Key Laboratory Cultivation Base of Ministry of Science and Technology), Nanjing, China
| | - Yang-Chun Han
- Laboratory for Quarantine of Alien Species, Integrated Technical Service Center of Jiangyin Customs, Jiangyin, China
| | - Lei Yang
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Jiangsu Key Laboratory for Food and Safety (State Key Laboratory Cultivation Base of Ministry of Science and Technology), Nanjing, China
| | - Jing Li
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Jiangsu Key Laboratory for Food and Safety (State Key Laboratory Cultivation Base of Ministry of Science and Technology), Nanjing, China
| | - Ary A Hoffmann
- School of BioSciences, Bio21 Institute, The University of Melbourne, Parkville, Australia
| | - Guang-Hua Luo
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Jiangsu Key Laboratory for Food and Safety (State Key Laboratory Cultivation Base of Ministry of Science and Technology), Nanjing, China
| | - Guo-Rui Yuan
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
| | - Ji-Chao Fang
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Jiangsu Key Laboratory for Food and Safety (State Key Laboratory Cultivation Base of Ministry of Science and Technology), Nanjing, China
| | - Rui Ji
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Jiangsu Key Laboratory for Food and Safety (State Key Laboratory Cultivation Base of Ministry of Science and Technology), Nanjing, China
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Xu R, Chong L, Zhu Y. Mediator kinase subunit CDK8 phosphorylates transcription factor TCP15 during tomato pollen development. PLANT PHYSIOLOGY 2024; 195:865-878. [PMID: 38365204 DOI: 10.1093/plphys/kiae079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 11/28/2023] [Accepted: 12/19/2023] [Indexed: 02/18/2024]
Abstract
Pollen development in flowering plants has strong implications for reproductive success. Pollen DNA can be targeted to improve plant traits for yield and stress tolerance. In this study, we demonstrated that the Mediator subunit CYCLIN-DEPENDENT KINASE 8 (CDK8) is a key modulator of pollen development in tomato (Solanum lycopersicum). SlCDK8 knockout led to significant decreases in pollen viability, fruit yield, and fruit seed number. We also found that SlCDK8 directly interacts with transcription factor TEOSINTE BRANCHED1-CYCLOIDEA-PCF15 (SlTCP15) using yeast two-hybrid screens. We subsequently showed that SlCDK8 phosphorylates Ser 187 of SlTCP15 to promote SlTCP15 stability. Phosphorylated TCP15 directly bound to the TGGGCY sequence in the promoters of DYSFUNCTIONAL TAPETUM 1 (SlDYT1) and MYB DOMAIN PROTEIN 103 (SlMYB103), which are responsible for pollen development. Consistently, disruption of SlTCP15 resembled slcdk8 tomato mutants. In sum, our work identified a new substrate of Mediator CDK8 and revealed an important regulatory role of SlCDK8 in pollen development via cooperation with SlTCP15.
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Affiliation(s)
- Rui Xu
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475001, China
| | - Leelyn Chong
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475001, China
| | - Yingfang Zhu
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475001, China
- Sanya Institute of Henan University, Sanya, Hainan 570203, China
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3
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Zu H, Jin G, Kong Y, Li Z, Lou Y, Li R. The N-terminal α2 helix element is critical for the activity of the rice transcription factor MYC2. PLANT MOLECULAR BIOLOGY 2024; 114:2. [PMID: 38189841 DOI: 10.1007/s11103-023-01411-y] [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: 09/21/2023] [Accepted: 11/21/2023] [Indexed: 01/09/2024]
Abstract
Jasmonates (JAs) are a class of phytohormones that play a crucial role in plant growth, development, and environmental stress responses. Central to JA signaling are the MYC2-type transcription factors, as they activate the expression of JA-responsive genes. We previously used CRISPR-Cas9-based genome editing to engineer rice OsMYC2 and yielded a mutant (myc2-5) with a single amino acid (aa) deletion (75I) outside the known functional domains of the protein. This myc2-5 mutant also showed some JA-deficient phenotypes, promoting us to investigate how 75I deletion affects JA responses. The mutation is found in the α2 helix element at the N-terminal of OsMYC2. The deletion of 75I in OsMYC2 rendered plants deficient in most of the JA responses, including root growth, leaf senescence, spikelet development, and resistance to pathogens and herbivores. Biochemical assays revealed that the 75I deletion markedly reduced OsMYC2 protein accumulation, subsequently diminishing its transcriptional activity. However, the deletion did not influence the protein's subcellular localization, DNA-binding capability, or its interactions with JAZ transcriptional repressors and the Mediator complex subunit MED25. Additionally, the screening of seven other deletions in the α2 helix further reinforces the importance of this protein element. Our results highlight the significance of the α2 helix in the N-terminus for OsMYC2's functionality, primarily through modulating its protein levels. This insight expands our knowledge of JA signaling and opens new avenues for research into the yet-to-be-explored domains of the MYC2 protein, with the potential to tailor JA responses in rice and other plant species.
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Affiliation(s)
- Hongyue Zu
- Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Insect Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Gaochen Jin
- Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Insect Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Yaze Kong
- Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Insect Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Zhaoyang Li
- Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Insect Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Yonggen Lou
- Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Insect Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Ran Li
- Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Insect Sciences, Zhejiang University, Hangzhou, 310058, China.
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Ningbo University, Ningbo, 315211, China.
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4
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Yuan C, Hu Y, Liu Q, Xu J, Zhou W, Yu H, Shen L, Qin C. MED8 regulates floral transition in Arabidopsis by interacting with FPA. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 116:1234-1247. [PMID: 37565662 DOI: 10.1111/tpj.16419] [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: 05/18/2023] [Revised: 07/04/2023] [Accepted: 07/31/2023] [Indexed: 08/12/2023]
Abstract
Success in plant reproduction is highly dependent on the correct timing of the floral transition, which is tightly regulated by the flowering pathways. In the model plant Arabidopsis thaliana, the central flowering repressor FLOWERING LOCUS C (FLC) is precisely regulated by multiple flowering time regulators in the vernalization pathway and autonomous pathway, including FPA. Here we report that Arabidopsis MEDIATOR SUBUNIT 8 (MED8) promotes floral transition in Arabidopsis by recruiting FPA to the FLC locus to repress FLC expression. Loss of MED8 function leads to a significant late-flowering phenotype due to increased FLC expression. We further show that MED8 directly interacts with FPA in the nucleus and recruits FPA to the FLC locus. Moreover, MED8 is indispensable for FPA's function in controlling flowering time and regulating FLC expression. Our study thus reveals a flowering mechanism by which the Mediator subunit MED8 represses FLC expression by facilitating the binding of FPA to the FLC locus to ensure appropriate timing of flowering for reproductive success.
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Affiliation(s)
- Chen Yuan
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 311121, China
| | - Yikai Hu
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 311121, China
| | - Qinggang Liu
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 311121, China
| | - Jingya Xu
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 311121, China
| | - Wei Zhou
- Temasek Life Sciences Laboratory, National University of Singapore, 117604, Singapore
| | - Hao Yu
- Temasek Life Sciences Laboratory, National University of Singapore, 117604, Singapore
- Department of Biological Sciences, Faculty of Science, National University of Singapore, 117543, Singapore
| | - Lisha Shen
- Temasek Life Sciences Laboratory, National University of Singapore, 117604, Singapore
| | - Cheng Qin
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 311121, China
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5
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Cao X, Du Q, Guo Y, Wang Y, Jiao Y. Condensation of STM is critical for shoot meristem maintenance and salt tolerance in Arabidopsis. MOLECULAR PLANT 2023; 16:1445-1459. [PMID: 37674313 DOI: 10.1016/j.molp.2023.09.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 05/20/2023] [Accepted: 09/04/2023] [Indexed: 09/08/2023]
Abstract
The shoot meristem generates the entire shoot system and is precisely maintained throughout the life cycle under various environmental challenges. In this study, we identified a prion-like domain (PrD) in the key shoot meristem regulator SHOOT MERISTEMLESS (STM), which distinguishes STM from other related KNOX1 proteins. We demonstrated that PrD stimulates STM to form nuclear condensates, which are required for maintaining the shoot meristem. STM nuclear condensate formation is stabilized by selected PrD-containing STM-interacting BELL proteins in vitro and in vivo. Moreover, condensation of STM promotes its interaction with the Mediator complex subunit MED8 and thereby enhances its transcriptional activity. Thus, condensate formation emerges as a novel regulatory mechanism of shoot meristem functions. Furthermore, we found that the formation of STM condensates is enhanced upon salt stress, which allows enhanced salt tolerance and increased shoot branching. Our findings highlight that the transcription factor partitioning plays an important role in cell fate determination and might also act as a tunable environmental acclimation mechanism.
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Affiliation(s)
- Xiuwei Cao
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Qingwei Du
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China; Beijing Agro-Biotechnology Research Center, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, China
| | - Yahe Guo
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Ying Wang
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Yuling Jiao
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China; State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China; Peking University Institute of Advanced Agricultural Sciences, Shandong Laboratory of Advanced Agricultural Sciences in Weifang, Weifang, Shandong 261325, China; College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
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6
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Awasthi P, Mishra AK, Kocábek T, Nath VS, Mishra S, Hazzouri KM, Sudalaimuthuasari N, Stajner N, Jakše J, Krofta K, Hájek T, Amiri KM. CRISPR/Cas9-mediated mutagenesis of the mediator complex subunits MED5a and MED5b genes impaired secondary metabolite accumulation in hop (Humulus lupulus). PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2023; 201:107851. [PMID: 37354728 DOI: 10.1016/j.plaphy.2023.107851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 06/15/2023] [Accepted: 06/17/2023] [Indexed: 06/26/2023]
Abstract
Hop (Humulus lupulus L.) is an important commercial crop known for the biosynthesis of valuable specialized secondary metabolites in glandular trichomes (lupulin glands), which are used for the brewing industry. To achieve burgeoning market demands is the essentiality of comprehensive understanding of the mechanisms of biosynthesis of secondary metabolites in hop. Over the past year, several studies using structural biology and functional genomics approaches have shown that Mediator (MED) serves as an integrative hub for RNAP II-mediated transcriptional regulation of various physiological and cellular processes, including involvement of MED5a and MED5b in hyperaccumulation of phenylpropanoid in A. thaliana. In the present work, an unprecedented attempt was made to generate Hlmed5a/med5b double loci mutant lines in hop using a CRISPR/Cas9-based genome editing system. The Hlmed5a/med5b double loci mutant lines showed reduced expression of structural genes of the flavonoid, humulone, and terpenoid biosynthetic pathways, which was more pronounced in the lupulin gland compared to leaf tissue and was consistent with their reduced accumulation. Phenotypic and anatomical observations revealed that Hlmed5a/med5b double loci mutant line exhibited robust growth, earlier flowering, earlier cone maturity, reduced cone size, variations in floral structure patterns, and distorted lupulin glands without any remarkable changes in leaf morphology, intensity of leaf color, and chlorophyll content. Comparative transcriptome analysis of leaf and lupulin gland tissues indicates that the expression of enzymatic genes related to secondary metabolite biosynthesis, phytohormone biosynthesis, floral organs, flowering time, and trichome development, including other genes related to starch and sucrose metabolism and defense mechanisms, were differentially modulated in the Hlmed5a/med5b lines. The combined results from functional and transcriptomic analyses illuminates the pivotal function of HlMED5a and HlMED5b in homeostasis of secondary meatbolites accumulation in hop.
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Affiliation(s)
- Praveen Awasthi
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Zygmunta Noskowskiego 12/14, 61-704, Poznań, Poland
| | - Ajay Kumar Mishra
- Khalifa Centre for Genetic Engineering and Biotechnology, United Arab Emirates University, P.O. Box. Al Ain 15551, United Arab Emirates.
| | - Tomáš Kocábek
- Biology Centre, Czech Academy of Sciences, Institute of Plant Molecular Biology, Branišovská 31, 370 05, České Budějovice, Czech Republic
| | - Vishnu Sukumari Nath
- Khalifa Centre for Genetic Engineering and Biotechnology, United Arab Emirates University, P.O. Box. Al Ain 15551, United Arab Emirates
| | - Sagarika Mishra
- Khalifa Centre for Genetic Engineering and Biotechnology, United Arab Emirates University, P.O. Box. Al Ain 15551, United Arab Emirates
| | - Khaled M Hazzouri
- Khalifa Centre for Genetic Engineering and Biotechnology, United Arab Emirates University, P.O. Box. Al Ain 15551, United Arab Emirates
| | - Naganeeswaran Sudalaimuthuasari
- Khalifa Centre for Genetic Engineering and Biotechnology, United Arab Emirates University, P.O. Box. Al Ain 15551, United Arab Emirates
| | - Natasa Stajner
- Department of Agronomy, Biotechnical Faculty, University of Ljubljana, 1000, Ljubljana, Slovenia
| | - Jernej Jakše
- Department of Agronomy, Biotechnical Faculty, University of Ljubljana, 1000, Ljubljana, Slovenia
| | - Karel Krofta
- Hop Research Institute, Co. Ltd., Kadaňská 2525, 438 46, Žatec, Czech Republic
| | - Tomáš Hájek
- University of South Bohemia, Faculty of Science, Branišovská 1716/31c, 370 05, České Budějovice, Czech Republic
| | - Khaled Ma Amiri
- Khalifa Centre for Genetic Engineering and Biotechnology, United Arab Emirates University, P.O. Box. Al Ain 15551, United Arab Emirates.
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7
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Zeng Q, Song L, Xia M, Zheng Z, Chen Z, Che X, Liu D. Overexpression of AHL proteins enhances root hair production by altering the transcription of RHD6-downstream genes. PLANT DIRECT 2023; 7:e517. [PMID: 37577137 PMCID: PMC10416611 DOI: 10.1002/pld3.517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 05/20/2023] [Accepted: 07/03/2023] [Indexed: 08/15/2023]
Abstract
AT-HOOK MOTIF NUCLEAR LOCALIZED (AHL) proteins occur in all sequenced plant species. They bind to the AT-rich DNA sequences in chromosomes and regulate gene transcription related to diverse biological processes. However, the molecular mechanism underlying how AHL proteins regulate gene transcription is poorly understood. In this research, we used root hair production as a readout to study the function of two Arabidopsis AHL proteins, AHL17, and its closest homolog AHL28. Overexpression of AHL17 or AHL28 greatly enhanced root hair production by increasing the transcription of an array of genes downstream of RHD6. RHD6 is a key transcription factor that regulates root hair development. Mutation of RHD6 completely suppressed the overproduction of root hairs by blocking the transcription of AHL17-activated genes. The overexpression of AHL17 or AHL28, however, neither affected the transcription of RHD6 nor the accumulation of RHD6 protein. These two AHL proteins also did not directly interact with RHD6. Furthermore, we found that three members of the Heat Shock Protein70 family, which have been annotated as the subunits of the plant Mediator complex, could form a complex with both AHL17 and RHD6. Our research might reveal a previously unrecognized mechanism of how AHL proteins regulate gene transcription.
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Affiliation(s)
- Qike Zeng
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, School of Life SciencesTsinghua UniversityBeijingChina
| | - Li Song
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest ChinaSichuan Agricultural University at WenjiangChengduChina
| | - Mingzhe Xia
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, School of Life SciencesTsinghua UniversityBeijingChina
| | - Zai Zheng
- Hainan Yazhou Bay Seed LaboratorySanyaChina
| | - Ziang Chen
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, School of Life SciencesTsinghua UniversityBeijingChina
| | - Ximing Che
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, School of Life SciencesTsinghua UniversityBeijingChina
| | - Dong Liu
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, School of Life SciencesTsinghua UniversityBeijingChina
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8
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Deng L, Yang T, Li Q, Chang Z, Sun C, Jiang H, Meng X, Huang T, Li CB, Zhong S, Li C. Tomato MED25 regulates fruit ripening by interacting with EIN3-like transcription factors. THE PLANT CELL 2023; 35:1038-1057. [PMID: 36471914 PMCID: PMC10015170 DOI: 10.1093/plcell/koac349] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 12/05/2022] [Indexed: 06/17/2023]
Abstract
Fruit ripening relies on the precise spatiotemporal control of RNA polymerase II (Pol II)-dependent gene transcription, and the evolutionarily conserved Mediator (MED) coactivator complex plays an essential role in this process. In tomato (Solanum lycopersicum), a model climacteric fruit, ripening is tightly coordinated by ethylene and several key transcription factors. However, the mechanism underlying the transmission of context-specific regulatory signals from these ripening-related transcription factors to the Pol II transcription machinery remains unknown. Here, we report the mechanistic function of MED25, a subunit of the plant Mediator transcriptional coactivator complex, in controlling the ethylene-mediated transcriptional program during fruit ripening. Multiple lines of evidence indicate that MED25 physically interacts with the master transcription factors of the ETHYLENE-INSENSITIVE 3 (EIN3)/EIN3-LIKE (EIL) family, thereby playing an essential role in pre-initiation complex formation during ethylene-induced gene transcription. We also show that MED25 forms a transcriptional module with EIL1 to regulate the expression of ripening-related regulatory as well as structural genes through promoter binding. Furthermore, the EIL1-MED25 module orchestrates both positive and negative feedback transcriptional circuits, along with its downstream regulators, to fine-tune ethylene homeostasis during fruit ripening.
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Affiliation(s)
- Lei Deng
- State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Innovative Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tianxia Yang
- State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Innovative Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qian Li
- Department of Pomology, College of Horticulture, China Agricultural University, Beijing 100193, China
| | - Zeqian Chang
- State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Innovative Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chuanlong Sun
- State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Innovative Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hongling Jiang
- State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Innovative Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xianwen Meng
- State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai’an 271018, China
| | - Tingting Huang
- Institute of Vegetable, Qingdao Academy of Agricultural Sciences, Qingdao 266100, China
| | - Chang-Bao Li
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Ministry of Agriculture, Beijing Vegetable Research Center, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, China
| | - Silin Zhong
- State Key Laboratory of Agrobiotechnology, School of Life Sciences, Chinese University of Hong Kong, Hong Kong 999077, China
| | - Chuanyou Li
- State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Innovative Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China
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9
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Lambert É, Puwakdandawa K, Tao YF, Robert F. From structure to molecular condensates: emerging mechanisms for Mediator function. FEBS J 2023; 290:286-309. [PMID: 34698446 DOI: 10.1111/febs.16250] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 10/15/2021] [Accepted: 10/25/2021] [Indexed: 02/05/2023]
Abstract
Mediator is a large modular protein assembly whose function as a coactivator of transcription is conserved in all eukaryotes. The Mediator complex can integrate and relay signals from gene-specific activators bound at enhancers to activate the general transcription machinery located at promoters. It has thus been described as a bridge between these elements during initiation of transcription. Here, we review recent studies on Mediator relating to its structure, gene specificity and general requirement, roles in chromatin architecture as well as novel concepts involving phase separation and transcriptional bursting. We revisit the mechanism of action of Mediator and ultimately put forward models for its mode of action in gene activation.
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Affiliation(s)
- Élie Lambert
- Institut de recherches cliniques de Montréal, Canada
| | | | - Yi Fei Tao
- Institut de recherches cliniques de Montréal, Canada
| | - François Robert
- Institut de recherches cliniques de Montréal, Canada.,Département de Médecine, Faculté de Médecine, Université de Montréal, Canada
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10
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Bajracharya A, Xi J, Grace KF, Bayer EE, Grant CA, Clutton CH, Baerson SR, Agarwal AK, Qiu Y. PHYTOCHROME-INTERACTING FACTOR 4/HEMERA-mediated thermosensory growth requires the Mediator subunit MED14. PLANT PHYSIOLOGY 2022; 190:2706-2721. [PMID: 36063057 PMCID: PMC9706435 DOI: 10.1093/plphys/kiac412] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 08/12/2022] [Indexed: 05/19/2023]
Abstract
While moderately elevated ambient temperatures do not trigger stress responses in plants, they do substantially stimulate the growth of specific organs through a process known as thermomorphogenesis. The basic helix-loop-helix transcription factor PHYTOCHROME-INTERACTING FACTOR 4 (PIF4) plays a central role in regulating thermomorphogenetic hypocotyl elongation in various plant species, including Arabidopsis (Arabidopsis thaliana). Although it is well known that PIF4 and its co-activator HEMERA (HMR) promote plant thermosensory growth by activating genes involved in the biosynthesis and signaling of the phytohormone auxin, the detailed molecular mechanism of such transcriptional activation is not clear. In this report, we investigated the role of the Mediator complex in the PIF4/HMR-mediated thermoresponsive gene expression. Through the characterization of various mutants of the Mediator complex, a tail subunit named MED14 was identified as an essential factor for thermomorphogenetic hypocotyl growth. MED14 was required for the thermal induction of PIF4 target genes but had a marginal effect on the levels of PIF4 and HMR. Further transcriptomic analyses confirmed that the expression of numerous PIF4/HMR-dependent, auxin-related genes required MED14 at warm temperatures. Moreover, PIF4 and HMR physically interacted with MED14 and both were indispensable for the association of MED14 with the promoters of these thermoresponsive genes. While PIF4 did not regulate MED14 levels, HMR was required for the transcript abundance of MED14. Taken together, these results unveil an important thermomorphogenetic mechanism, in which PIF4 and HMR recruit the Mediator complex to activate auxin-related growth-promoting genes when plants sense moderate increases in ambient temperature.
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Affiliation(s)
| | - Jing Xi
- Natural Products Utilization Research Unit, U.S. Department of Agriculture, Agricultural Research Service, Oxford, Mississippi, USA
| | - Karlie F Grace
- Department of Biology, University of Mississippi, Oxford, Mississippi 38677, USA
| | - Eden E Bayer
- Department of Biology, University of Mississippi, Oxford, Mississippi 38677, USA
| | - Chloe A Grant
- Department of Biology, University of Mississippi, Oxford, Mississippi 38677, USA
| | - Caroline H Clutton
- Department of Biology, University of Mississippi, Oxford, Mississippi 38677, USA
| | - Scott R Baerson
- Natural Products Utilization Research Unit, U.S. Department of Agriculture, Agricultural Research Service, Oxford, Mississippi, USA
| | - Ameeta K Agarwal
- National Center for Natural Products Research, School of Pharmacy, University of Mississippi, Oxford, Mississippi, USA
- Division of Pharmacology, Department of BioMolecular Sciences, School of Pharmacy, University of Mississippi, Oxford, Mississippi, USA
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11
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Liao CJ, Hailemariam S, Sharon A, Mengiste T. Pathogenic strategies and immune mechanisms to necrotrophs: Differences and similarities to biotrophs and hemibiotrophs. CURRENT OPINION IN PLANT BIOLOGY 2022; 69:102291. [PMID: 36063637 DOI: 10.1016/j.pbi.2022.102291] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 07/20/2022] [Accepted: 07/23/2022] [Indexed: 06/15/2023]
Abstract
Pathogenesis in plant diseases is complex comprising diverse pathogen virulence and plant immune mechanisms. These pathogens cause damaging plant diseases by deploying specialized and generic virulence strategies that are countered by intricate resistance mechanisms. The significant challenges that necrotrophs pose to crop production are predicted to increase with climate change. Immunity to biotrophs and hemibiotrophs is dominated by intracellular receptors that recognize specific effectors and activate resistance. These mechanisms play only minor roles in resistance to necrotrophs. Pathogen- or host-derived conserved pattern molecules trigger immune responses that broadly contribute to plant immunity. However, certain pathogen or host-derived immune elicitors are enriched by the virulence activities of necrotrophs. Different plant hormones modulate systemic resistance and cell death that have differential impacts on resistance to pathogens of different lifestyles. Knowledge of mechanisms that contribute to resistance to necrotrophs has expanded. Besides toxins and cell wall degrading enzymes that dominate the pathogenesis of necrotrophs, other effectors with subtle contributions are being identified.
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Affiliation(s)
- Chao-Jan Liao
- Department of Botany and Plant Pathology, Purdue University, 915 W. State Street, West Lafayette, IN 47907, USA
| | - Sara Hailemariam
- Department of Botany and Plant Pathology, Purdue University, 915 W. State Street, West Lafayette, IN 47907, USA
| | - Amir Sharon
- Department of Molecular Biology and Ecology of Plants, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Tesfaye Mengiste
- Department of Botany and Plant Pathology, Purdue University, 915 W. State Street, West Lafayette, IN 47907, USA.
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12
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Agrawal R, Sharma M, Dwivedi N, Maji S, Thakur P, Junaid A, Fajkus J, Laxmi A, Thakur JK. MEDIATOR SUBUNIT17 integrates jasmonate and auxin signaling pathways to regulate thermomorphogenesis. PLANT PHYSIOLOGY 2022; 189:2259-2280. [PMID: 35567489 PMCID: PMC9342970 DOI: 10.1093/plphys/kiac220] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 04/20/2022] [Indexed: 05/16/2023]
Abstract
Plant adjustment to environmental changes involves complex crosstalk between extrinsic and intrinsic cues. In the past two decades, extensive research has elucidated the key roles of PHYTOCHROME-INTERACTING FACTOR4 (PIF4) and the phytohormone auxin in thermomorphogenesis. In this study, we identified a previously unexplored role of jasmonate (JA) signaling components, the Mediator complex, and their integration with auxin signaling during thermomorphogenesis in Arabidopsis (Arabidopsis thaliana). Warm temperature induces expression of JA signaling genes including MYC2, but, surprisingly, this transcriptional activation is not JA dependent. Warm temperature also promotes accumulation of the JA signaling receptor CORONATINE INSENSITIVE1 (COI1) and degradation of the JA signaling repressor JASMONATE-ZIM-DOMAIN PROTEIN9, which probably leads to de-repression of MYC2, enabling it to contribute to the expression of MEDIATOR SUBUNIT17 (MED17). In response to warm temperature, MED17 occupies the promoters of thermosensory genes including PIF4, YUCCA8 (YUC8), INDOLE-3-ACETIC ACID INDUCIBLE19 (IAA19), and IAA29. Moreover, MED17 facilitates enrichment of H3K4me3 on the promoters of PIF4, YUC8, IAA19, and IAA29 genes. Interestingly, both occupancy of MED17 and enrichment of H3K4me3 on these thermomorphogenesis-related promoters are dependent on PIF4 (or PIFs). Altered accumulation of COI1 under warm temperature in the med17 mutant suggests the possibility of a feedback mechanism. Overall, this study reveals the role of the Mediator complex as an integrator of JA and auxin signaling pathways during thermomorphogenesis.
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Affiliation(s)
- Rekha Agrawal
- Plant Mediator Lab, National Institute of Plant Genome Research, New Delhi 110067, India
| | - Mohan Sharma
- Signalling Lab, National Institute of Plant Genome Research, New Delhi 110067, India
| | - Nidhi Dwivedi
- Plant Mediator Lab, National Institute of Plant Genome Research, New Delhi 110067, India
| | - Sourobh Maji
- Plant Mediator Lab, National Institute of Plant Genome Research, New Delhi 110067, India
| | - Pallabi Thakur
- Plant Mediator Lab, National Institute of Plant Genome Research, New Delhi 110067, India
| | - Alim Junaid
- Plant Mediator Lab, National Institute of Plant Genome Research, New Delhi 110067, India
| | - Jiří Fajkus
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Ashverya Laxmi
- Signalling Lab, National Institute of Plant Genome Research, New Delhi 110067, India
| | - Jitendra K Thakur
- Plant Mediator Lab, National Institute of Plant Genome Research, New Delhi 110067, India
- Plant Transcription Regulation Group, International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India
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13
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Chen J, Yang S, Fan B, Zhu C, Chen Z. The Mediator Complex: A Central Coordinator of Plant Adaptive Responses to Environmental Stresses. Int J Mol Sci 2022; 23:ijms23116170. [PMID: 35682844 PMCID: PMC9181133 DOI: 10.3390/ijms23116170] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 05/22/2022] [Accepted: 05/28/2022] [Indexed: 01/25/2023] Open
Abstract
As sessile organisms, plants are constantly exposed to a variety of environmental stresses and have evolved adaptive mechanisms, including transcriptional reprogramming, in order to survive or acclimate under adverse conditions. Over the past several decades, a large number of gene-specific transcription factors have been identified in the transcriptional regulation of plant adaptive responses. The Mediator complex plays a key role in transducing signals from gene-specific transcription factors to the transcription machinery to activate or repress target gene expression. Since its first purification about 15 years ago, plant Mediator complex has been extensively analyzed for its composition and biological functions. Mutants of many plant Mediator subunits are not lethal but are compromised in growth, development and response to biotic and abiotic stress, underscoring a particularly important role in plant adaptive responses. Plant Mediator subunits also interact with partners other than transcription factors and components of the transcription machinery, indicating the complexity of the regulation of gene expression by plant Mediator complex. Here, we present a comprehensive discussion of recent analyses of the structure and function of plant Mediator complex, with a particular focus on its roles in plant adaptive responses to a wide spectrum of environmental stresses and associated biological processes.
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Affiliation(s)
- Jialuo Chen
- College of Life Sciences, China Jiliang University, Hangzhou 310018, China; (J.C.); (S.Y.)
| | - Su Yang
- College of Life Sciences, China Jiliang University, Hangzhou 310018, China; (J.C.); (S.Y.)
| | - Baofang Fan
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, USA;
| | - Cheng Zhu
- College of Life Sciences, China Jiliang University, Hangzhou 310018, China; (J.C.); (S.Y.)
- Correspondence: (C.Z.); (Z.C.); Tel.: +86-571-8683-6090 (C.Z.); +1-765-494-4657 (Z.C.)
| | - Zhixiang Chen
- College of Life Sciences, China Jiliang University, Hangzhou 310018, China; (J.C.); (S.Y.)
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, USA;
- Correspondence: (C.Z.); (Z.C.); Tel.: +86-571-8683-6090 (C.Z.); +1-765-494-4657 (Z.C.)
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14
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Giustozzi M, Freytes SN, Jaskolowski A, Lichy M, Mateos J, Falcone Ferreyra ML, Rosano GL, Cerdán P, Casati P. Arabidopsis mediator subunit 17 connects transcription with DNA repair after UV-B exposure. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 110:1047-1067. [PMID: 35220621 DOI: 10.1111/tpj.15722] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 02/22/2022] [Accepted: 02/24/2022] [Indexed: 06/14/2023]
Abstract
Mediator 17 (MED17) is a subunit of the Mediator complex that regulates transcription initiation in eukaryotic organisms. In yeast and humans, MED17 also participates in DNA repair, physically interacting with proteins of the nucleotide excision DNA repair system, but this function in plants has not been investigated. We studied the role of MED17 in Arabidopsis plants exposed to UV-B radiation. Our results demonstrate that med17 and OE MED17 plants have altered responses to UV-B, and that MED17 participates in various aspects of the DNA damage response (DDR). Comparison of the med17 transcriptome with that of wild-type (WT) plants showed that almost one-third of transcripts with altered expression in med17 plants were also changed by UV-B exposure in WT plants. Increased sensitivity to DNA damage after UV-B in med17 plants could result from the altered regulation of UV-B responsive transcripts but MED17 also physically interacts with DNA repair proteins, suggesting a direct role of this Mediator subunit during repair. Finally, we show that MED17 is necessary to regulate the DDR activated by ataxia telangiectasia and Rad3 related (ATR), and that programmed cell death 5 (PDCD5) overexpression reverts the deficiencies in DDR shown in med17 mutants. Our data demonstrate that MED17 is an important regulator of DDR after UV-B irradiation in Arabidopsis.
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Affiliation(s)
- Marisol Giustozzi
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI), CONICET, Universidad Nacional de Rosario, 2000, Rosario, Argentina
| | | | - Aime Jaskolowski
- Fundación Instituto Leloir, IIBBA-CONICET, Buenos Aires, Argentina
| | - Micaela Lichy
- Fundación Instituto Leloir, IIBBA-CONICET, Buenos Aires, Argentina
| | - Julieta Mateos
- Fundación Instituto Leloir, IIBBA-CONICET, Buenos Aires, Argentina
| | - María Lorena Falcone Ferreyra
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI), CONICET, Universidad Nacional de Rosario, 2000, Rosario, Argentina
| | - Germán L Rosano
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Instituto de Biologia Molecular y Celular de Rosario (IBR), CONICET, Universidad Nacional de Rosario, 2000, Rosario, Argentina
| | - Pablo Cerdán
- Fundación Instituto Leloir, IIBBA-CONICET, Buenos Aires, Argentina
- Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Paula Casati
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI), CONICET, Universidad Nacional de Rosario, 2000, Rosario, Argentina
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15
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Zhu P, Lister C, Dean C. Cold-induced Arabidopsis FRIGIDA nuclear condensates for FLC repression. Nature 2021; 599:657-661. [PMID: 34732891 PMCID: PMC8612926 DOI: 10.1038/s41586-021-04062-5] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 09/27/2021] [Indexed: 11/09/2022]
Abstract
Plants use seasonal temperature cues to time the transition to reproduction. In Arabidopsis thaliana, winter cold epigenetically silences the floral repressor locus FLOWERING LOCUS C (FLC) through POLYCOMB REPRESSIVE COMPLEX 2 (PRC2)1. This vernalization process aligns flowering with spring. A prerequisite for silencing is transcriptional downregulation of FLC, but how this occurs in the fluctuating temperature regimes of autumn is unknown2-4. Transcriptional repression correlates with decreased local levels of histone H3 trimethylation at K36 (H3K36me3) and H3 trimethylation at K4 (H3K4me3)5,6, which are deposited during FRIGIDA (FRI)-dependent activation of FLC7-10. Here we show that cold rapidly promotes the formation of FRI nuclear condensates that do not colocalize with an active FLC locus. This correlates with reduced FRI occupancy at the FLC promoter and FLC repression. Warm temperature spikes reverse this process, buffering FLC shutdown to prevent premature flowering. The accumulation of condensates in the cold is affected by specific co-transcriptional regulators and cold induction of a specific isoform of the antisense RNA COOLAIR5,11. Our work describes the dynamic partitioning of a transcriptional activator conferring plasticity in response to natural temperature fluctuations, thus enabling plants to effectively monitor seasonal progression.
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Affiliation(s)
- Pan Zhu
- John Innes Centre, Norwich Research Park, Norwich, UK
| | - Clare Lister
- John Innes Centre, Norwich Research Park, Norwich, UK
| | - Caroline Dean
- John Innes Centre, Norwich Research Park, Norwich, UK.
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16
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Hu H, Tang Y, Wu J, Chen F, Yang Y, Pan X, Dong X, Jin X, Liu S, Du X. Brassica napus Mediator Subunit16 Induces BnMED25- and BnWRKY33-Activated Defense Signaling to Confer Sclerotinia sclerotiorum Resistance. FRONTIERS IN PLANT SCIENCE 2021; 12:663536. [PMID: 34489988 PMCID: PMC8417128 DOI: 10.3389/fpls.2021.663536] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 03/31/2021] [Indexed: 06/13/2023]
Abstract
The plant mediator is a highly conserved protein complex that interacts with transcription factors (TFs) and RNA polymerase II (RNAP II) to relay regulatory information during transcription. Plant immune response is one of the biological processes that is orchestrated by this regulatory mechanism. Brassica napus, an important oil crop, is severely attacked by a devastating disease Sclerotinia stem rot. Here, we explored broad-spectrum disease resistant roles of B. napus mediator subunit 16 (BnMED16) and its host defense mechanism against fugal pathogen Sclerotinia sclerotiorum. We found that BnMED16 expression was significantly increased by S. sclerotiorum infection, and its homologous overexpression resulted in rapid and comprehensive defense responses from the beginning to the end. This affected signal transduction with multiple channels including pathogen recognition, intracellular Ca2+ concentration, reactive oxygen species (ROS) accumulation and clearance, and activation of mitogen-activated protein kinase (MAPK) signaling cascades initially. Subsequently, pathogen-/defense-related genes and hormone-responsive pathways were highly activated, which resulted in enhanced cell wall and secretion of defense proteases. Furthermore, the biochemical analysis showed that BnMED16 interacts with BnMED25 and BnWRKY33. Additionally, BnMED25 also interacts with TFs BnMYC2, BnCOI1, and BnEIN3 of the JA/ET signal transduction pathway. Taken together, we proposed a hypothetical model that BnMED16 confers S. sclerotiorum resistance by enhancing BnMED25-mediated JA/ET defense pathways and BnWRKY33-activated defense signaling in B. napus. The BnMED16 overexpressing lines with enhanced broad-spectrum disease resistance could be useful for breeding Sclerotinia-resistant oilseed rape varieties, as well as serving as basis for further strategy development in resistance breeding.
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Affiliation(s)
- Huizhen Hu
- Southwest Research Center for Landscape Architecture Engineering, State Forestry and Grassland Administration, Yunnan Province Engineering Research Center for Functional Flower Resources and Industrialization, College of Landscape Architecture and Horticulture Sciences, Southwest Forestry University, Kunming, China
| | - Yiwei Tang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan, China
| | - Jian Wu
- Key Laboratory of Plant Functional Genomics of the Ministry of Education, Yangzhou University, Yangzhou, China
| | - Feizhi Chen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan, China
| | - Yidan Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan, China
| | - Xuancheng Pan
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan, China
| | - Xiang Dong
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan, China
| | - Xianda Jin
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan, China
| | - Sheng Liu
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Wuhan, China
| | - Xuezhu Du
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan, China
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17
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Ha CM, Rao X, Saxena G, Dixon RA. Growth-defense trade-offs and yield loss in plants with engineered cell walls. THE NEW PHYTOLOGIST 2021; 231:60-74. [PMID: 33811329 DOI: 10.1111/nph.17383] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 03/29/2021] [Indexed: 05/18/2023]
Abstract
As a major component of plant secondary cell walls, lignin provides structural integrity and rigidity, and contributes to primary defense by providing a physical barrier to pathogen ingress. Genetic modification of lignin biosynthesis has been adopted to reduce the recalcitrance of lignified cell walls to improve biofuel production, tree pulping properties and forage digestibility. However, lignin-modification is often, but unpredictably, associated with dwarf phenotypes. Hypotheses suggested to explain this include: collapsed vessels leading to defects in water and solute transport; accumulation of molecule(s) that are inhibitory to plant growth or deficiency of metabolites that are critical for plant growth; activation of defense pathways linked to cell wall integrity sensing. However, there is still no commonly accepted underlying mechanism for the growth defects. Here, we discuss recent data on transcriptional reprogramming in plants with modified lignin content and their corresponding suppressor mutants, and evaluate growth-defense trade-offs as a factor underlying the growth phenotypes. New approaches will be necessary to estimate how gross changes in transcriptional reprogramming may quantitatively affect growth. Better understanding of the basis for yield drag following cell wall engineering is important for the biotechnological exploitation of plants as factories for fuels and chemicals.
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Affiliation(s)
- Chan Man Ha
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, 1155 Union Circle #311428, Denton, TX, 76203, USA
- Center for Bioenergy Innovation (CBI), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Xiaolan Rao
- College of Life Sciences, Hubei University, No. 28 Nanli Road, Hong-shan District, Wuchang, Wuhan, Hubei Province, 430068, China
| | - Garima Saxena
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, 1155 Union Circle #311428, Denton, TX, 76203, USA
| | - Richard A Dixon
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, 1155 Union Circle #311428, Denton, TX, 76203, USA
- Center for Bioenergy Innovation (CBI), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
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18
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Suzuki G, Lucob-Agustin N, Kashihara K, Fujii Y, Inukai Y, Gomi K. Rice MEDIATOR25, OsMED25, is an essential subunit for jasmonate-mediated root development and OsMYC2-mediated leaf senescence. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2021; 306:110853. [PMID: 33775361 DOI: 10.1016/j.plantsci.2021.110853] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 02/11/2021] [Accepted: 02/15/2021] [Indexed: 06/12/2023]
Abstract
The Mediator multiprotein complex acts as a universal adaptor between transcription factors (TFs) and RNA polymerase II. MEDIATOR25 (MED25) has an important role in jasmonic acid (JA) signaling in Arabidopsis. However, no research has been conducted on the role of MED25 in JA signaling in rice, which is one of the most important food crops globally and is a model plant for molecular studies in other monocotyledonous species. In the present study, we isolated the loss-of function mutant of MED25, osmed25, through the map-based cloning and phenotypic complementation analysis by the introduction of OsMED25 and investigated the role of OsMED25 in JA signaling in rice. The osmed25 mutants had longer primary (seminal) roots than those of the wild-type (WT) and exhibited JA-insensitive phenotypes. S-type lateral root densities in osmed25 mutants were lower than those in the WT, whereas L-type lateral root densities in osmed25 mutants were higher than those in the WT. Furthermore, the osmed25 mutants retarded JA-regulated leaf senescence under dark-induced senescence. Mutated osmed25 protein could not interact with OsMYC2, which is a positive TF in JA signaling in rice. The expression of JA-responsive senescence-associated genes was not upregulated in response to JA in the osmed25 mutants. The results suggest that OsMED25 participates in JA-mediated root development and OsMYC2-mediated leaf senescence in rice.
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Affiliation(s)
- Go Suzuki
- Plant Genome and Resource Research Center, Faculty of Agriculture, Kagawa University, Miki, Kagawa, 761-0795, Japan
| | - Nonawin Lucob-Agustin
- Philippine Rice Research Institute, Central Experiment Station, Science City of Muñoz, Nueva Ecija, 3119, Philippines
| | - Keita Kashihara
- Plant Genome and Resource Research Center, Faculty of Agriculture, Kagawa University, Miki, Kagawa, 761-0795, Japan
| | - Yumi Fujii
- Plant Genome and Resource Research Center, Faculty of Agriculture, Kagawa University, Miki, Kagawa, 761-0795, Japan
| | - Yoshiaki Inukai
- International Center for Research and Education in Agriculture, Nagoya University, Nagoya, Aichi, 464-8601, Japan.
| | - Kenji Gomi
- Plant Genome and Resource Research Center, Faculty of Agriculture, Kagawa University, Miki, Kagawa, 761-0795, Japan.
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19
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Jiang J, Yang G, Xin Y, Wang Z, Yan W, Chen Z, Tang X, Xia J. Overexpression of OsMed16 Inhibits the Growth of Rice and Causes Spontaneous Cell Death. Genes (Basel) 2021; 12:genes12050656. [PMID: 33925652 PMCID: PMC8145620 DOI: 10.3390/genes12050656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 04/23/2021] [Accepted: 04/25/2021] [Indexed: 11/16/2022] Open
Abstract
The Mediator complex transduces information from the DNA-bound transcription factors to the RNA polymerase II transcriptional machinery. Research on plant Mediator subunits has primarily been performed in Arabidopsis, while very few of them have been functionally characterized in rice. In this study, the rice Mediator subunit 16, OsMed16, was examined. OsMed16 encodes a putative protein of 1301 amino acids, which is longer than the version previously reported. It was expressed in various rice organs and localized to the nucleus. The knockout of OsMed16 resulted in rice seedling lethality. Its overexpression led to the retardation of rice growth, low yield, and spontaneous cell death in the leaf blade and sheath. RNA sequencing suggested that the overexpression of OsMed16 altered the expression of a large number of genes. Among them, the upregulation of some defense-related genes was verified. OsMed16 can regulate the expression of a wealth of genes, and alterations in its expression have a profound impact on plant growth, development, and defense responses in rice.
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Affiliation(s)
- Jie Jiang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, China; (J.J.); (G.Y.); (Y.X.); (Z.W.)
| | - Guangzhe Yang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, China; (J.J.); (G.Y.); (Y.X.); (Z.W.)
| | - Yafeng Xin
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, China; (J.J.); (G.Y.); (Y.X.); (Z.W.)
| | - Zhigang Wang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, China; (J.J.); (G.Y.); (Y.X.); (Z.W.)
| | - Wei Yan
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou 510631, China;
- Shenzhen Institute of Molecular Crop Design, Shenzhen 518107, China;
| | - Zhufeng Chen
- Shenzhen Institute of Molecular Crop Design, Shenzhen 518107, China;
- Shenzhen Agricultural Technology Promotion Center, Shenzhen 518055, China
| | - Xiaoyan Tang
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou 510631, China;
- Shenzhen Institute of Molecular Crop Design, Shenzhen 518107, China;
- Correspondence: (X.T.); (J.X.)
| | - Jixing Xia
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, China; (J.J.); (G.Y.); (Y.X.); (Z.W.)
- Correspondence: (X.T.); (J.X.)
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20
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Guo P, Chong L, Wu F, Hsu CC, Li C, Zhu JK, Zhu Y. Mediator tail module subunits MED16 and MED25 differentially regulate abscisic acid signaling in Arabidopsis. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2021; 63:802-815. [PMID: 33369119 DOI: 10.1111/jipb.13062] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 12/19/2020] [Indexed: 05/06/2023]
Abstract
MED25 has been implicated as a negative regulator of the abscisic acid (ABA) signaling pathway. However, it is unclear whether other Mediator subunits could associate with MED25 to participate in the ABA response. Here, we used affinity purification followed by mass spectrometry to uncover Mediator subunits that associate with MED25 in transgenic plants. We found that at least 26 Mediator subunits, belonging to the head, middle, tail, and CDK8 kinase modules, were co-purified with MED25 in vivo. Interestingly, the tail module subunit MED16 was identified to associate with MED25 under both mock and ABA treatments. We further showed that the disruption of MED16 led to reduced ABA sensitivity compared to the wild type. Transcriptomic analysis revealed that the expression of several ABA-responsive genes was significantly lower in med16 than those in wild type. Furthermore, we discovered that MED16 may possibly compete with MED25 to interact with the key transcription factor ABA INSENSITIVE 5 (ABI5) to positively regulate ABA signaling. Consistently, med16 and med25 mutants displayed opposite phenotypes in ABA response, cuticle permeability, and differential ABI5-mediated EM1 and EM6 expression. Together, our data indicate that MED16 and MED25 differentially regulate ABA signaling by antagonistically affecting ABI5-mediated transcription in Arabidopsis.
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Affiliation(s)
- Pengcheng Guo
- State Key Laboratory of Crop Stress Adaptation and Improvement, Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng, 475001, China
| | - Leelyn Chong
- State Key Laboratory of Crop Stress Adaptation and Improvement, Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng, 475001, China
| | - Fangming Wu
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, the Chinese Academy of Sciences, Beijing, 100101, China
| | - Chuan-Chih Hsu
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529
| | - Chuanyou Li
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, the Chinese Academy of Sciences, Beijing, 100101, China
| | - Jian-Kang Zhu
- Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences, the Chinese Academy of Sciences, Shanghai, 200032, China
- Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana, 47907, USA
| | - Yingfang Zhu
- State Key Laboratory of Crop Stress Adaptation and Improvement, Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng, 475001, China
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21
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Guo J, Wei L, Chen SS, Cai XW, Su YN, Li L, Chen S, He XJ. The CBP/p300 histone acetyltransferases function as plant-specific MEDIATOR subunits in Arabidopsis. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2021; 63:755-771. [PMID: 33325122 DOI: 10.1111/jipb.13052] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 12/10/2020] [Indexed: 05/06/2023]
Abstract
In eukaryotes, MEDIATOR is a conserved multi-subunit complex that links transcription factors and RNA polymerase II and that thereby facilitates transcriptional initiation. Although the composition of MEDIATOR has been well studied in yeast and mammals, relatively little is known about the composition of MEDIATOR in plants. By affinity purification followed by mass spectrometry, we identified 28 conserved MEDIATOR subunits in Arabidopsis thaliana, including putative MEDIATOR subunits that were not previously validated. Our results indicated that MED34, MED35, MED36, and MED37 are not Arabidopsis MEDIATOR subunits, as previously proposed. Our results also revealed that two homologous CBP/p300 histone acetyltransferases, HAC1 and HAC5 (HAC1/5) are in fact plant-specific MEDIATOR subunits. The MEDIATOR subunits MED8 and MED25 (MED8/25) are partially responsible for the association of MEDIATOR with HAC1/5, MED8/25 and HAC1/5 co-regulate gene expression and thereby affect flowering time and floral development. Our in vitro observations indicated that MED8 and HAC1 form liquid-like droplets by phase separation, and our in vivo observations indicated that these droplets co-localize in the nuclear bodies at a subset of nuclei. The formation of liquid-like droplets is required for MED8 to interact with RNA polymerase II. In summary, we have identified all of the components of Arabidopsis MEDIATOR and revealed the mechanism underlying the link of histone acetylation and transcriptional regulation.
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Affiliation(s)
- Jing Guo
- National Institute of Biological Sciences, Beijing, 102206, China
- Graduate School of Peking Union Medical College, Beijing, 100730, China
| | - Long Wei
- National Institute of Biological Sciences, Beijing, 102206, China
| | - Shan-Shan Chen
- National Institute of Biological Sciences, Beijing, 102206, China
| | - Xue-Wei Cai
- National Institute of Biological Sciences, Beijing, 102206, China
| | - Yin-Na Su
- National Institute of Biological Sciences, Beijing, 102206, China
| | - Lin Li
- National Institute of Biological Sciences, Beijing, 102206, China
| | - She Chen
- National Institute of Biological Sciences, Beijing, 102206, China
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, 100084, China
| | - Xin-Jian He
- National Institute of Biological Sciences, Beijing, 102206, China
- Graduate School of Peking Union Medical College, Beijing, 100730, China
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, 100084, China
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22
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Liu H, Timko MP. Jasmonic Acid Signaling and Molecular Crosstalk with Other Phytohormones. Int J Mol Sci 2021; 22:ijms22062914. [PMID: 33805647 PMCID: PMC8000993 DOI: 10.3390/ijms22062914] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 03/10/2021] [Accepted: 03/11/2021] [Indexed: 12/15/2022] Open
Abstract
Plants continually monitor their innate developmental status and external environment and make adjustments to balance growth, differentiation and stress responses using a complex and highly interconnected regulatory network composed of various signaling molecules and regulatory proteins. Phytohormones are an essential group of signaling molecules that work through a variety of different pathways conferring plasticity to adapt to the everchanging developmental and environmental cues. Of these, jasmonic acid (JA), a lipid-derived molecule, plays an essential function in controlling many different plant developmental and stress responses. In the past decades, significant progress has been made in our understanding of the molecular mechanisms that underlie JA metabolism, perception, signal transduction and its crosstalk with other phytohormone signaling pathways. In this review, we discuss the JA signaling pathways starting from its biosynthesis to JA-responsive gene expression, highlighting recent advances made in defining the key transcription factors and transcriptional regulatory proteins involved. We also discuss the nature and degree of crosstalk between JA and other phytohormone signaling pathways, highlighting recent breakthroughs that broaden our knowledge of the molecular bases underlying JA-regulated processes during plant development and biotic stress responses.
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23
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Lee M, Dominguez-Ferreras A, Kaliyadasa E, Huang WJ, Antony E, Stevenson T, Lehmann S, Schäfer P, Knight MR, Ntoukakis V, Knight H. Mediator Subunits MED16, MED14, and MED2 Are Required for Activation of ABRE-Dependent Transcription in Arabidopsis. FRONTIERS IN PLANT SCIENCE 2021; 12:649720. [PMID: 33777083 PMCID: PMC7991908 DOI: 10.3389/fpls.2021.649720] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 02/12/2021] [Indexed: 05/29/2023]
Abstract
The Mediator complex controls transcription of most eukaryotic genes with individual subunits required for the control of particular gene regulons in response to various perturbations. In this study, we reveal the roles of the plant Mediator subunits MED16, MED14, and MED2 in regulating transcription in response to the phytohormone abscisic acid (ABA) and we determine which cis elements are under their control. Using synthetic promoter reporters we established an effective system for testing relationships between subunits and specific cis-acting motifs in protoplasts. Our results demonstrate that MED16, MED14, and MED2 are required for the full transcriptional activation by ABA of promoters containing both the ABRE (ABA-responsive element) and DRE (drought-responsive element). Using synthetic promoter motif concatamers, we showed that ABA-responsive activation of the ABRE but not the DRE motif was dependent on these three Mediator subunits. Furthermore, the three subunits were required for the control of water loss from leaves but played no role in ABA-dependent growth inhibition, highlighting specificity in their functions. Our results identify new roles for three Mediator subunits, provide a direct demonstration of their function and highlight that our experimental approach can be utilized to identify the function of subunits of plant transcriptional regulators.
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Affiliation(s)
- Morgan Lee
- Department of Biosciences, Durham University, Durham, United Kingdom
| | - Anna Dominguez-Ferreras
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
- Warwick Integrative Synthetic Biology Centre, University of Warwick, Coventry, United Kingdom
| | - Ewon Kaliyadasa
- Department of Biosciences, Durham University, Durham, United Kingdom
| | - Wei-Jie Huang
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
- Warwick Integrative Synthetic Biology Centre, University of Warwick, Coventry, United Kingdom
| | - Edna Antony
- Department of Biosciences, Durham University, Durham, United Kingdom
| | - Tracey Stevenson
- Department of Biosciences, Durham University, Durham, United Kingdom
| | - Silke Lehmann
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
- Warwick Integrative Synthetic Biology Centre, University of Warwick, Coventry, United Kingdom
| | - Patrick Schäfer
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
- Warwick Integrative Synthetic Biology Centre, University of Warwick, Coventry, United Kingdom
- Institute of Molecular Botany, Ulm University, Ulm, Germany
| | - Marc R. Knight
- Department of Biosciences, Durham University, Durham, United Kingdom
| | - Vardis Ntoukakis
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
- Warwick Integrative Synthetic Biology Centre, University of Warwick, Coventry, United Kingdom
| | - Heather Knight
- Department of Biosciences, Durham University, Durham, United Kingdom
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24
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Agrawal R, Jiří F, Thakur JK. The kinase module of the Mediator complex: an important signalling processor for the development and survival of plants. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:224-240. [PMID: 32945869 DOI: 10.1093/jxb/eraa439] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 09/16/2020] [Indexed: 05/06/2023]
Abstract
Mediator, a multisubunit protein complex, is a signal processor that conveys regulatory information from transcription factors to RNA polymerase II and therefore plays an important role in the regulation of gene expression. This megadalton complex comprises four modules, namely, the head, middle, tail, and kinase modules. The first three modules form the core part of the complex, whereas association of the kinase module is facultative. The kinase module is able to alter the function of Mediator and has been established as a major transcriptional regulator of numerous developmental and biochemical processes. The kinase module consists of MED12, MED13, CycC, and kinase CDK8. Upon association with Mediator, the kinase module can alter its structure and function dramatically. In the past decade, research has established that the kinase module is very important for plant growth and development, and in the fight against biotic and abiotic challenges. However, there has been no comprehensive review discussing these findings in detail and depth. In this review, we survey the regulation of kinase module subunits and highlight their many functions in plants. Coordination between the subunits to process different signals for optimum plant growth and development is also discussed.
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Affiliation(s)
- Rekha Agrawal
- Plant Mediator Lab, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, India
| | - Fajkus Jiří
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Jitendra K Thakur
- Plant Mediator Lab, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, India
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25
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Signal Integration by Cyclin-Dependent Kinase 8 (CDK8) Module and Other Mediator Subunits in Biotic and Abiotic Stress Responses. Int J Mol Sci 2020; 22:ijms22010354. [PMID: 33396301 PMCID: PMC7795602 DOI: 10.3390/ijms22010354] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 12/28/2020] [Accepted: 12/28/2020] [Indexed: 12/21/2022] Open
Abstract
Environmental stresses have driven plants to develop various mechanisms to acclimate in adverse conditions. Extensive studies have demonstrated that a significant reprogramming occurs in the plant transcriptome in response to biotic and abiotic stresses. The highly conserved and large multi-subunit transcriptional co-activator of eukaryotes, known as the Mediator, has been reported to play a substantial role in the regulation of important genes that help plants respond to environmental perturbances. CDK8 module is a relatively new component of the Mediator complex that has been shown to contribute to plants' defense, development, and stress responses. Previous studies reported that CDK8 module predominantly acts as a transcriptional repressor in eukaryotic cells by reversibly associating with core Mediator. However, growing evidence has demonstrated that depending on the type of biotic and abiotic stress, the CDK8 module may perform a contrasting regulatory role. This review will summarize the current knowledge of CDK8 module as well as other previously documented Mediator subunits in plant cell signaling under stress conditions.
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26
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Zhu XF, Wu Q, Meng YT, Tao Y, Shen RF. AtHAP5A regulates iron translocation in iron-deficient Arabidopsis thaliana. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2020; 62:1910-1925. [PMID: 33405355 DOI: 10.1111/jipb.12984] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 06/16/2020] [Indexed: 06/12/2023]
Abstract
Iron (Fe) deficient plants employ multiple strategies to increase root uptake and root-to-shoot translocation of Fe. The identification of genes that are responsible for these processes, and a comprehensive understanding of the regulatory effects of transcriptional networks on their expression, including transcription factors (TFs), is underway in Arabidopsis thaliana. Here, we show that a Histone- or heme-associated proteins (HAP) transcription factor (TF), HAP5A, is necessary for the response to Fe deficiency in Arabidopsis. Its expression was induced under Fe deficiency, and the lack of HAP5A significantly decreased Fe translocation from the root to the shoot, resulting in substantial chlorosis of the newly expanded leaves, compared with the wild-type (WT, Col-0). Further analysis found that the expression of a gene encoding nicotianamine (NA) synthase (NAS1) was dramatically decreased in the hap5a mutant, regardless of the Fe status. Yeast-one-hybrid and ChIP analyses suggested that HAP5A directly binds to the promoter region of NAS1. Moreover, overexpression of NAS1 could rescue the chlorosis phenotype of hap5a in Fe deficient conditions. In summary, a novel pathway was elucidated, showing that NAS1-dependent translocation of Fe from the root to the shoot is controlled by HAP5A in Fe-deficient Arabidopsis thaliana.
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Affiliation(s)
- Xiao Fang Zhu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Qi Wu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yu Ting Meng
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ye Tao
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ren Fang Shen
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
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27
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Chong L, Guo P, Zhu Y. Mediator Complex: A Pivotal Regulator of ABA Signaling Pathway and Abiotic Stress Response in Plants. Int J Mol Sci 2020; 21:ijms21207755. [PMID: 33092161 PMCID: PMC7588972 DOI: 10.3390/ijms21207755] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 10/16/2020] [Accepted: 10/19/2020] [Indexed: 01/09/2023] Open
Abstract
As an evolutionarily conserved multi-protein complex, the Mediator complex modulates the association between transcription factors and RNA polymerase II to precisely regulate gene transcription. Although numerous studies have shown the diverse functions of Mediator complex in plant development, flowering, hormone signaling, and biotic stress response, its roles in the Abscisic acid (ABA) signaling pathway and abiotic stress response remain largely unclear. It has been recognized that the phytohormone, ABA, plays a predominant role in regulating plant adaption to various abiotic stresses as ABA can trigger extensive changes in the transcriptome to help the plants respond to environmental stimuli. Over the past decade, the Mediator complex has been revealed to play key roles in not only regulating the ABA signaling transduction but also in the abiotic stress responses. In this review, we will summarize current knowledge of the Mediator complex in regulating the plants’ response to ABA as well as to the abiotic stresses of cold, drought and high salinity. We will particularly emphasize the involvement of multi-functional subunits of MED25, MED18, MED16, and CDK8 in response to ABA and environmental perturbation. Additionally, we will discuss potential research directions available for further deciphering the role of Mediator complex in regulating ABA and other abiotic stress responses.
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28
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Mielecki J, Gawroński P, Karpiński S. Retrograde Signaling: Understanding the Communication between Organelles. Int J Mol Sci 2020; 21:E6173. [PMID: 32859110 PMCID: PMC7503960 DOI: 10.3390/ijms21176173] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 08/16/2020] [Accepted: 08/20/2020] [Indexed: 12/21/2022] Open
Abstract
Understanding how cell organelles and compartments communicate with each other has always been an important field of knowledge widely explored by many researchers. However, despite years of investigations, one point-and perhaps the only point that many agree on-is that our knowledge about cellular-signaling pathways still requires expanding. Chloroplasts and mitochondria (because of their primary functions in energy conversion) are important cellular sensors of environmental fluctuations and feedback they provide back to the nucleus is important for acclimatory responses. Under stressful conditions, it is important to manage cellular resources more efficiently in order to maintain a proper balance between development, growth and stress responses. For example, it can be achieved through regulation of nuclear and organellar gene expression. If plants are unable to adapt to stressful conditions, they will be unable to efficiently produce energy for growth and development-and ultimately die. In this review, we show the importance of retrograde signaling in stress responses, including the induction of cell death and in organelle biogenesis. The complexity of these pathways demonstrates how challenging it is to expand the existing knowledge. However, understanding this sophisticated communication may be important to develop new strategies of how to improve adaptability of plants in rapidly changing environments.
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Affiliation(s)
| | | | - Stanisław Karpiński
- Department of Plant Genetics, Breeding and Biotechnology, Institute of Biology, Warsaw University of Life Sciences, 02-787 Warsaw, Poland; (J.M.); (P.G.)
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29
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Liu Q, Bischof S, Harris CJ, Zhong Z, Zhan L, Nguyen C, Rashoff A, Barshop WD, Sun F, Feng S, Potok M, Gallego-Bartolome J, Zhai J, Wohlschlegel JA, Carey MF, Long JA, Jacobsen SE. The characterization of Mediator 12 and 13 as conditional positive gene regulators in Arabidopsis. Nat Commun 2020; 11:2798. [PMID: 32493925 PMCID: PMC7271234 DOI: 10.1038/s41467-020-16651-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 05/14/2020] [Indexed: 12/18/2022] Open
Abstract
Mediator 12 (MED12) and MED13 are components of the Mediator multi-protein complex, that facilitates the initial steps of gene transcription. Here, in an Arabidopsis mutant screen, we identify MED12 and MED13 as positive gene regulators, both of which contribute broadly to morc1 de-repressed gene expression. Both MED12 and MED13 are preferentially required for the expression of genes depleted in active chromatin marks, a chromatin signature shared with morc1 re-activated loci. We further discover that MED12 tends to interact with genes that are responsive to environmental stimuli, including light and radiation. We demonstrate that light-induced transient gene expression depends on MED12, and is accompanied by a concomitant increase in MED12 enrichment during induction. In contrast, the steady-state expression level of these genes show little dependence on MED12, suggesting that MED12 is primarily required to aid the expression of genes in transition from less-active to more active states. Mediator is a multiprotein complex required to activate gene transcription by RNAPII. Here, the authors report that MED12 and MED13 are conditional positive regulators that facilitate the expression of genes depleted in active chromatin marks and the induction of gene expression in response to environmental stimuli in Arabidopsis.
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Affiliation(s)
- Qikun Liu
- School of Advanced Agricultural Sciences, Peking University, 100871, Beijing, China. .,Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, CA, 90095, USA.
| | - Sylvain Bischof
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, CA, 90095, USA.,Department of Plant and Microbial Biology and Zurich-Basel Plant Science Center, University of Zurich, Zollikerstrasse 107, 8008, Zurich, Switzerland
| | - C Jake Harris
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - Zhenhui Zhong
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, CA, 90095, USA.,Basic Forestry and Proteomics Center, Fujian Agriculture and Forestry University, 350002, Fuzhou, China
| | - Lingyu Zhan
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - Calvin Nguyen
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - Andrew Rashoff
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - William D Barshop
- Department of Biological Chemistry, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - Fei Sun
- Department of Biological Chemistry, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - Suhua Feng
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - Magdalena Potok
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - Javier Gallego-Bartolome
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - Jixian Zhai
- Institute of Plant and Food Science, Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - James A Wohlschlegel
- Department of Biological Chemistry, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - Michael F Carey
- Department of Biological Chemistry, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - Jeffrey A Long
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - Steven E Jacobsen
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, CA, 90095, USA. .,Howard Hughes Medical Institute, University of California at Los Angeles, Los Angeles, CA, 90095, USA.
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30
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Chardon F, Cueff G, Delannoy E, Aubé F, Lornac A, Bedu M, Gilard F, Pateyron S, Rogniaux H, Gargaros A, Mireau H, Rajjou L, Martin-Magniette ML, Budar F. The Consequences of a Disruption in Cyto-Nuclear Coadaptation on the Molecular Response to a Nitrate Starvation in Arabidopsis. PLANTS (BASEL, SWITZERLAND) 2020; 9:E573. [PMID: 32369924 PMCID: PMC7285260 DOI: 10.3390/plants9050573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 04/20/2020] [Accepted: 04/22/2020] [Indexed: 12/04/2022]
Abstract
Mitochondria and chloroplasts are important actors in the plant nutritional efficiency. So, it could be expected that a disruption of the coadaptation between nuclear and organellar genomes impact plant response to nutrient stresses. We addressed this issue using two Arabidopsis accessions, namely Ct1 and Jea, and their reciprocal cytolines possessing the nuclear genome from one parent and the organellar genomes of the other one. We measured gene expression, and quantified proteins and metabolites under N starvation and non-limiting conditions. We observed a typical response to N starvation at the phenotype and molecular levels. The phenotypical response to N starvation was similar in the cytolines compared to the parents. However, we observed an effect of the disruption of genomic coadaptation at the molecular levels, distinct from the previously described responses to organellar stresses. Strikingly, genes differentially expressed in cytolines compared to parents were mainly repressed in the cytolines. These genes encoded more mitochondrial and nuclear proteins than randomly expected, while N starvation responsive ones were enriched in genes for chloroplast and nuclear proteins. In cytolines, the non-coadapted cytonuclear genomic combination tends to modulate the response to N starvation observed in the parental lines on various biological processes.
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Affiliation(s)
- Fabien Chardon
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France; (G.C.); (F.A.); (A.L.); (M.B.); (H.M.); (L.R.)
| | - Gwendal Cueff
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France; (G.C.); (F.A.); (A.L.); (M.B.); (H.M.); (L.R.)
| | - Etienne Delannoy
- Institute of Plant Sciences Paris-Saclay (IPS2), Université Paris-Saclay, CNRS, INRAE, Univ Evry, 91405 Orsay, France; (E.D.); (F.G.); (S.P.); (M.-L.M.-M.)
- CNRS, INRAE, Institute of Plant Sciences Paris-Saclay (IPS2), Université de Paris, 91405 Orsay, France
| | - Fabien Aubé
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France; (G.C.); (F.A.); (A.L.); (M.B.); (H.M.); (L.R.)
| | - Aurélia Lornac
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France; (G.C.); (F.A.); (A.L.); (M.B.); (H.M.); (L.R.)
| | - Magali Bedu
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France; (G.C.); (F.A.); (A.L.); (M.B.); (H.M.); (L.R.)
| | - Françoise Gilard
- Institute of Plant Sciences Paris-Saclay (IPS2), Université Paris-Saclay, CNRS, INRAE, Univ Evry, 91405 Orsay, France; (E.D.); (F.G.); (S.P.); (M.-L.M.-M.)
- CNRS, INRAE, Institute of Plant Sciences Paris-Saclay (IPS2), Université de Paris, 91405 Orsay, France
| | - Stéphanie Pateyron
- Institute of Plant Sciences Paris-Saclay (IPS2), Université Paris-Saclay, CNRS, INRAE, Univ Evry, 91405 Orsay, France; (E.D.); (F.G.); (S.P.); (M.-L.M.-M.)
- CNRS, INRAE, Institute of Plant Sciences Paris-Saclay (IPS2), Université de Paris, 91405 Orsay, France
| | - Hélène Rogniaux
- INRAE, UR BIA, F-44316 Nantes, France; (H.R.); (A.G.)
- INRAE, BIBS Facility, F-44316 Nantes, France
| | - Audrey Gargaros
- INRAE, UR BIA, F-44316 Nantes, France; (H.R.); (A.G.)
- INRAE, BIBS Facility, F-44316 Nantes, France
| | - Hakim Mireau
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France; (G.C.); (F.A.); (A.L.); (M.B.); (H.M.); (L.R.)
| | - Loïc Rajjou
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France; (G.C.); (F.A.); (A.L.); (M.B.); (H.M.); (L.R.)
| | - Marie-Laure Martin-Magniette
- Institute of Plant Sciences Paris-Saclay (IPS2), Université Paris-Saclay, CNRS, INRAE, Univ Evry, 91405 Orsay, France; (E.D.); (F.G.); (S.P.); (M.-L.M.-M.)
- CNRS, INRAE, Institute of Plant Sciences Paris-Saclay (IPS2), Université de Paris, 91405 Orsay, France
- UMR MIA-Paris, AgroParisTech, INRA, Université Paris-Saclay, 75005 Paris, France
| | - Françoise Budar
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France; (G.C.); (F.A.); (A.L.); (M.B.); (H.M.); (L.R.)
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The Important Function of Mediator Complex in Controlling the Developmental Transitions in Plants. Int J Mol Sci 2020; 21:ijms21082733. [PMID: 32326439 PMCID: PMC7215822 DOI: 10.3390/ijms21082733] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 04/09/2020] [Accepted: 04/11/2020] [Indexed: 12/24/2022] Open
Abstract
Developmental transitions in plants are tightly associated with changes in the transcriptional regulation of gene expression. One of the most important regulations is conferred by cofactors of RNA polymerase II including the mediator complex, a large complex with a modular organization. The mediator complex recruits transcription factors to bind to the specific sites of genes including protein-coding genes and non-coding RNA genes to promote or repress the transcription initiation and elongation using a protein-protein interaction module. Mediator complex subunits have been isolated and identified in plants and the function of most mediator subunits in whole life cycle plants have been revealed. Studies have shown that the Mediator complex is indispensable for the regulation of plant developmental transitions by recruiting age-, flowering-, or hormone-related transcription factors. Here, we first overviewed the Mediator subunits in plants, and then we summarized the specific Mediator subunits involved in developmental transitions, including vegetative phase change and floral transition. Finally, we proposed the future directions to further explore their roles in plants. The link between Mediator subunits and developmental transitions implies the necessity to explore targets of this complex as a potential application in developing high quality crop varieties.
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Nath VS, Shrestha A, Awasthi P, Mishra AK, Kocábek T, Matoušek J, Sečnik A, Jakše J, Radišek S, Hallan V. Mapping the Gene Expression Spectrum of Mediator Subunits in Response to Viroid Infection in Plants. Int J Mol Sci 2020; 21:E2498. [PMID: 32260277 PMCID: PMC7177877 DOI: 10.3390/ijms21072498] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 03/31/2020] [Accepted: 04/01/2020] [Indexed: 12/25/2022] Open
Abstract
The mediator (MED) represents a large, conserved, multi-subunit protein complex that regulates gene expression through interactions with RNA polymerase II and enhancer-bound transcription factors. Expanding research accomplishments suggest the predominant role of plant MED subunits in the regulation of various physiological and developmental processes, including the biotic stress response against bacterial and fungal pathogens. However, the involvement of MED subunits in virus/viroid pathogenesis remains elusive. In this study, we investigated for the first time the gene expression modulation of selected MED subunits in response to five viroid species (Apple fruit crinkle viroid (AFCVd), Citrus bark cracking viroid (CBCVd), Hop latent viroid (HLVd), Hop stunt viroid (HSVd), and Potato spindle tuber viroid (PSTVd)) in two model plant species (Nicotiana tabacum and N. benthamiana) and a commercially important hop (Humulus lupulus) cultivar. Our results showed a differential expression pattern of MED subunits in response to a viroid infection. The individual plant MED subunits displayed a differential and tailored expression pattern in response to different viroid species, suggesting that the MED expression is viroid- and plant species-dependent. The explicit evidence obtained from our results warrants further investigation into the association of the MED subunit with symptom development. Together, we provide a comprehensive portrait of MED subunit expression in response to viroid infection and a plausible involvement of MED subunits in fine-tuning transcriptional reprogramming in response to viroid infection, suggesting them as a potential candidate for rewiring the defense response network in plants against pathogens.
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Affiliation(s)
- Vishnu Sukumari Nath
- Department of Molecular Genetics, Biology Centre of the Czech Academy of Sciences, Institute of Plant Molecular Biology, Branišovská 31, 370 05 Ceske Budejovice, Czech Republic; (V.S.N.); (A.S.); (P.A.); (T.K.); (J.M.)
| | - Ankita Shrestha
- Department of Molecular Genetics, Biology Centre of the Czech Academy of Sciences, Institute of Plant Molecular Biology, Branišovská 31, 370 05 Ceske Budejovice, Czech Republic; (V.S.N.); (A.S.); (P.A.); (T.K.); (J.M.)
| | - Praveen Awasthi
- Department of Molecular Genetics, Biology Centre of the Czech Academy of Sciences, Institute of Plant Molecular Biology, Branišovská 31, 370 05 Ceske Budejovice, Czech Republic; (V.S.N.); (A.S.); (P.A.); (T.K.); (J.M.)
| | - Ajay Kumar Mishra
- Department of Molecular Genetics, Biology Centre of the Czech Academy of Sciences, Institute of Plant Molecular Biology, Branišovská 31, 370 05 Ceske Budejovice, Czech Republic; (V.S.N.); (A.S.); (P.A.); (T.K.); (J.M.)
| | - Tomáš Kocábek
- Department of Molecular Genetics, Biology Centre of the Czech Academy of Sciences, Institute of Plant Molecular Biology, Branišovská 31, 370 05 Ceske Budejovice, Czech Republic; (V.S.N.); (A.S.); (P.A.); (T.K.); (J.M.)
| | - Jaroslav Matoušek
- Department of Molecular Genetics, Biology Centre of the Czech Academy of Sciences, Institute of Plant Molecular Biology, Branišovská 31, 370 05 Ceske Budejovice, Czech Republic; (V.S.N.); (A.S.); (P.A.); (T.K.); (J.M.)
| | - Andrej Sečnik
- Department of Agronomy, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana, Slovenia; (A.S.); (J.J.)
| | - Jernej Jakše
- Department of Agronomy, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana, Slovenia; (A.S.); (J.J.)
| | - Sebastjan Radišek
- Plant Protection Department, Slovenian Institute of Hop Research and Brewing, Cesta Žalskega Tabora 2, SI-3310 Žalec, Slovenia;
| | - Vipin Hallan
- CSIR-Institute of Himalayan Bioresource Technology, Palampur 176061, India;
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Crawford T, Karamat F, Lehotai N, Rentoft M, Blomberg J, Strand Å, Björklund S. Specific functions for Mediator complex subunits from different modules in the transcriptional response of Arabidopsis thaliana to abiotic stress. Sci Rep 2020; 10:5073. [PMID: 32193425 PMCID: PMC7081235 DOI: 10.1038/s41598-020-61758-w] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 02/26/2020] [Indexed: 11/22/2022] Open
Abstract
Adverse environmental conditions are detrimental to plant growth and development. Acclimation to abiotic stress conditions involves activation of signaling pathways which often results in changes in gene expression via networks of transcription factors (TFs). Mediator is a highly conserved co-regulator complex and an essential component of the transcriptional machinery in eukaryotes. Some Mediator subunits have been implicated in stress-responsive signaling pathways; however, much remains unknown regarding the role of plant Mediator in abiotic stress responses. Here, we use RNA-seq to analyze the transcriptional response of Arabidopsis thaliana to heat, cold and salt stress conditions. We identify a set of common abiotic stress regulons and describe the sequential and combinatorial nature of TFs involved in their transcriptional regulation. Furthermore, we identify stress-specific roles for the Mediator subunits MED9, MED16, MED18 and CDK8, and putative TFs connecting them to different stress signaling pathways. Our data also indicate different modes of action for subunits or modules of Mediator at the same gene loci, including a co-repressor function for MED16 prior to stress. These results illuminate a poorly understood but important player in the transcriptional response of plants to abiotic stress and identify target genes and mechanisms as a prelude to further biochemical characterization.
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Affiliation(s)
- Tim Crawford
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, 901 87, Sweden
- Institute for Biochemistry and Biology, University of Potsdam, Potsdam, Germany
| | - Fazeelat Karamat
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, 901 87, Sweden
| | - Nóra Lehotai
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, 901 87, Sweden
| | - Matilda Rentoft
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, 901 87, Sweden
| | - Jeanette Blomberg
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, 901 87, Sweden
| | - Åsa Strand
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, 901 87, Sweden
| | - Stefan Björklund
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, 901 87, Sweden.
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Mao X, Weake VM, Chapple C. Mediator function in plant metabolism revealed by large-scale biology. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:5995-6003. [PMID: 31504746 DOI: 10.1093/jxb/erz372] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 08/07/2019] [Indexed: 05/16/2023]
Abstract
Mediator is a multisubunit transcriptional co-regulator that is involved in the regulation of an array of processes including plant metabolism. The pathways regulated by Mediator-dependent processes include those for the synthesis of phenylpropanoids (MED5), cellulose (MED16), lipids (MED15 and CDK8), and the regulation of iron homeostasis (MED16 and MED25). Traditional genetic and biochemical approaches laid the foundation for our understanding of Mediator function, but recent transcriptomic and metabolomic studies have provided deeper insights into how specific subunits cooperate in the regulation of plant metabolism. In this review, we highlight recent developments in the investigation of Mediator and plant metabolism, with particular emphasis on the large-scale biology studies of med mutants.
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Affiliation(s)
- Xiangying Mao
- Department of Biochemistry, Purdue University, West Lafayette, IN, USA
- Purdue Center for Plant Biology, Purdue University, West Lafayette, IN, USA
| | - Vikki M Weake
- Department of Biochemistry, Purdue University, West Lafayette, IN, USA
- Purdue University Center for Cancer Research, Purdue University, West Lafayette, IN, USA
| | - Clint Chapple
- Department of Biochemistry, Purdue University, West Lafayette, IN, USA
- Purdue Center for Plant Biology, Purdue University, West Lafayette, IN, USA
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35
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Zhai Q, Li C. The plant Mediator complex and its role in jasmonate signaling. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:3415-3424. [PMID: 31089685 PMCID: PMC6609880 DOI: 10.1093/jxb/erz233] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Accepted: 05/07/2019] [Indexed: 05/20/2023]
Abstract
The Mediator complex is an essential, multisubunit transcriptional coactivator that is highly conserved in eukaryotes. Mediator interacts with gene-specific transcription factors, the RNA polymerase II transcriptional machinery, as well as several other factors involved in transcription, and acts as an integral hub to regulate various aspects of transcription. Recent studies of the plant Mediator complex have established that it functions in diverse aspects of plant development and fitness. Jasmonate (JA) is an oxylipin-derived plant hormone that regulates plant immunity and development. The basic helix-loop-helix transcription factor MYC2, which is a master regulator of JA signaling, orchestrates genome-wide transcriptional reprogramming of plant cells to coordinate defense- and growth-related processes. Here, we review the function of the plant Mediator complex in regulating JA signaling. We focus on the multifunctional Mediator subunit MED25, which emerges as an integrative hub for the transcriptional regulation of jasmonate signaling.
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Affiliation(s)
- Qingzhe Zhai
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, China
| | - Chuanyou Li
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
- Correspondence:
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36
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Garg J, Saettone A, Nabeel-Shah S, Cadorin M, Ponce M, Marquez S, Pu S, Greenblatt J, Lambert JP, Pearlman RE, Fillingham J. The Med31 Conserved Component of the Divergent Mediator Complex in Tetrahymena thermophila Participates in Developmental Regulation. Curr Biol 2019; 29:2371-2379.e6. [PMID: 31280994 DOI: 10.1016/j.cub.2019.06.052] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 05/18/2019] [Accepted: 06/18/2019] [Indexed: 11/24/2022]
Abstract
Mediator is a large protein complex required for basal and regulated expression of most RNA polymerase II (RNAP II)-transcribed genes, in part due to its interaction with and phosphorylation of the conserved C-terminal domain (CTD) of Rpb1 [1, 2]. Mediator has been implicated in many aspects of gene expression including chromatin looping [3], higher-order chromatin folding [4], mRNA processing [5] and export [6], and transcriptional memory [7]. Mediator is thought to have played a major role during eukaryotic diversification [8, 9], although its function remains unknown in evolutionarily deep branching eukaryotes lacking canonical CTD heptad repeats. We used the ciliate protozoan Tetrahymena thermophila as a model organism whose genome encodes a highly divergent Rpb1 lacking canonical CTD heptad repeats. We endogenously tagged the Med31 subunit of the Mediator complex and performed affinity purification coupled with mass spectrometry (AP-MS) to identify Mediator subunits. We found that Med31 physically interacts with a large number of proteins (>20), several of which share similarities to canonical Mediator subunits in yeast and humans as well as Tetrahymena-specific proteins. Furthermore, Med31 ChIP-seq analysis suggested a global role for Mediator in transcription regulation. We demonstrated that MED31 knockdown in growing Tetrahymena results in the ectopic expression of developmental genes important for programmed DNA rearrangements. In addition, indirect immunofluorescence revealed Med31 localization in meiotic micronuclei, implicating Mediator in RNAPII-dependent ncRNA transcription. Our results reveal structural and functional insights and implicate Mediator as an ancient cellular machinery for transcription regulation with a possible involvement in global transcription of ncRNAs.
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Affiliation(s)
- Jyoti Garg
- Department of Biology, York University, 4700 Keele Street, Toronto, ON M3J 1P3, Canada
| | - Alejandro Saettone
- Department of Chemistry and Biology, Ryerson University, 350 Victoria Street, Toronto, ON M5B 2K3, Canada
| | - Syed Nabeel-Shah
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada; Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Matthew Cadorin
- Department of Chemistry and Biology, Ryerson University, 350 Victoria Street, Toronto, ON M5B 2K3, Canada
| | - Marcelo Ponce
- SciNet HPC Consortium, University of Toronto, 661 University Avenue, Suite 1140, Toronto, ON M5G 1M1, Canada
| | - Susanna Marquez
- Department of Biology, York University, 4700 Keele Street, Toronto, ON M3J 1P3, Canada
| | - Shuye Pu
- Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Jack Greenblatt
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada; Donnelly Centre, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Jean-Philippe Lambert
- Department of Molecular Medicine and Cancer Research Centre, Université Laval, Quebec, QC, Canada; CHU de Québec Research Center, CHUL, 2705 Laurier Boulevard, Quebec, QC G1V 4G2, Canada
| | - Ronald E Pearlman
- Department of Biology, York University, 4700 Keele Street, Toronto, ON M3J 1P3, Canada
| | - Jeffrey Fillingham
- Department of Chemistry and Biology, Ryerson University, 350 Victoria Street, Toronto, ON M5B 2K3, Canada.
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37
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Mao X, Kim JI, Wheeler MT, Heintzelman AK, Weake VM, Chapple C. Mutation of Mediator subunit CDK8 counteracts the stunted growth and salicylic acid hyperaccumulation phenotypes of an Arabidopsis MED5 mutant. THE NEW PHYTOLOGIST 2019; 223:233-245. [PMID: 30756399 DOI: 10.1111/nph.15741] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 02/08/2019] [Indexed: 05/13/2023]
Abstract
The Mediator complex functions as a hub for transcriptional regulation. MED5, an Arabidopsis Mediator tail subunit, is required for maintaining phenylpropanoid homeostasis. A semidominant mutation (ref4-3) that causes a single amino acid substitution in MED5b functions as a strong suppressor of the pathway, leading to decreased soluble phenylpropanoid accumulation, reduced lignin content and dwarfism. By contrast, loss of MED5 results in increased concentrations of phenylpropanoids. We used a reverse genetic approach to identify suppressors of ref4-3 and found that ref4-3 requires CDK8, a kinase module subunit of Mediator, to repress plant growth. The genetic interaction between MED5 and CDK8 was further characterized using mRNA-sequencing (RNA-seq) and metabolite analysis. Growth inhibition and suppression of phenylpropanoid metabolism can be genetically separated in ref4-3 by elimination of CDK8 kinase activity; however, the stunted growth of ref4-3 is not dependent on the phosphorylation event introduced by the G383S mutation. In addition, rather than perturbation of lignin biosynthesis, misregulation of DJC66, a gene encoding a DNAJ protein, is involved in the dwarfism of the med5 mutants. Together, our study reveals genetic interactions between Mediator tail and kinase module subunits and enhances our understanding of dwarfing in phenylpropanoid pathway mutants.
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Affiliation(s)
- Xiangying Mao
- Department of Biochemistry, Purdue University, West Lafayette, IN, 47907, USA
- Purdue Center for Plant Biology, Purdue University, West Lafayette, IN, 47907, USA
| | - Jeong Im Kim
- Department of Biochemistry, Purdue University, West Lafayette, IN, 47907, USA
| | - Mitchell T Wheeler
- Department of Biochemistry, Purdue University, West Lafayette, IN, 47907, USA
| | - Anne K Heintzelman
- Department of Biochemistry, Purdue University, West Lafayette, IN, 47907, USA
- Northwest Missouri State University, Maryville, MO, 64468, USA
| | - Vikki M Weake
- Department of Biochemistry, Purdue University, West Lafayette, IN, 47907, USA
- Purdue University Center for Cancer Research, Purdue University, West Lafayette, IN, 47907, USA
| | - Clint Chapple
- Department of Biochemistry, Purdue University, West Lafayette, IN, 47907, USA
- Purdue Center for Plant Biology, Purdue University, West Lafayette, IN, 47907, USA
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38
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Fornero C, Rickerd T, Kirik V. Papillae formation on Arabidopsis leaf trichomes requires the function of Mediator tail subunits 2, 14, 15a, 16, and 25. PLANTA 2019; 249:1063-1071. [PMID: 30535640 DOI: 10.1007/s00425-018-3063-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 12/05/2018] [Indexed: 06/09/2023]
Abstract
Arabidopsis Mediator subunits 2, 14, 15a, 16, and 25 are required for papillae development on the trichome cell wall surface. Arabidopsis leaf hairs exhibit raised protrusions, termed papillae, on their cell wall surfaces. Here, we show that the glassy hair mutant, glh2, exhibits trichomes with an approximate 11-fold decrease in papillae density on their surfaces in comparison to wild type. This phenotype was found to be the result of mutations in Arabidopsis Mediator subunit 16. MED16 is localized to the nucleus of trichomes, consistent with Mediator's role in transcription. The expression patterns of the trichome development reporters, ETR2pro::GUS and GL2pro::GUS, as well as GL2 transcript levels were not altered in the glh2 mutant. Screening of available T-DNA insertion lines in other subunits of the Mediator tail module revealed glassy trichome phenotypes in med2, med14, and med15a mutants. The data suggest that the Mediator complex is required for expression of genes involved in trichome papillae development.
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Affiliation(s)
- Christy Fornero
- School of Biological Sciences, Illinois State University, Normal, IL, 61790, USA
| | - Trevor Rickerd
- School of Biological Sciences, Illinois State University, Normal, IL, 61790, USA
| | - Viktor Kirik
- School of Biological Sciences, Illinois State University, Normal, IL, 61790, USA.
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Suzaki T, Takeda N, Nishida H, Hoshino M, Ito M, Misawa F, Handa Y, Miura K, Kawaguchi M. LACK OF SYMBIONT ACCOMMODATION controls intracellular symbiont accommodation in root nodule and arbuscular mycorrhizal symbiosis in Lotus japonicus. PLoS Genet 2019; 15:e1007865. [PMID: 30605473 PMCID: PMC6317779 DOI: 10.1371/journal.pgen.1007865] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 11/30/2018] [Indexed: 11/19/2022] Open
Abstract
Nitrogen-fixing rhizobia and arbuscular mycorrhizal fungi (AMF) form symbioses with plant roots and these are established by precise regulation of symbiont accommodation within host plant cells. In model legumes such as Lotus japonicus and Medicago truncatula, rhizobia enter into roots through an intracellular invasion system that depends on the formation of a root-hair infection thread (IT). While IT-mediated intracellular rhizobia invasion is thought to be the most evolutionarily derived invasion system, some studies have indicated that a basal intercellular invasion system can replace it when some nodulation-related factors are genetically modified. In addition, intracellular rhizobia accommodation is suggested to have a similar mechanism as AMF accommodation. Nevertheless, our understanding of the underlying genetic mechanisms is incomplete. Here we identify a L. japonicus nodulation-deficient mutant, with a mutation in the LACK OF SYMBIONT ACCOMMODATION (LAN) gene, in which root-hair IT formation is strongly reduced, but intercellular rhizobial invasion eventually results in functional nodule formation. LjLAN encodes a protein that is homologous to Arabidopsis MEDIATOR 2/29/32 possibly acting as a subunit of a Mediator complex, a multiprotein complex required for gene transcription. We also show that LjLAN acts in parallel with a signaling pathway including LjCYCLOPS. In addition, the lan mutation drastically reduces the colonization levels of AMF. Taken together, our data provide a new factor that has a common role in symbiont accommodation process during root nodule and AM symbiosis. Symbiosis between plants and beneficial microbes such as nitrogen-fixing bacteria and arbuscular mycorrhizal fungi has enabled plant colonization of new environments. Root nodule symbiosis with nitrogen-fixing rhizobia enables sessile plants to survive in a nitrogen-deficient environment. To establish the symbiosis, host plant cells need to accommodate rhizobia during nodule development, a process mediated by a plant-derived intracellular structure called the infection thread (IT). In this study, we show that LACK OF SYMBIONT ACCOMMODATION (LAN) is involved in intracellular rhizobia accommodation in the model leguminous plant Lotus japonicus. LjLAN encodes a putative subunit of Mediator complex, a multiprotein complex that has a fundamental role as an activator of gene transcription. Mutation analysis suggests that LjLAN is required for root hair IT formation, which enables swift and efficient rhizobial accommodation. Moreover, we show that LjLAN is required for symbiosis with arbuscular mycorrhizal fungi. These data add a new component to the molecular mechanism relevant to the establishment of root nodule and arbuscular mycorrhizal symbiosis.
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Affiliation(s)
- Takuya Suzaki
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
- College of Biological Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
- Tsukuba Plant-Innovation Research Center, University of Tsukuba, Tsukuba, Ibaraki, Japan
- * E-mail:
| | - Naoya Takeda
- Graduate School of Science and Technology, Kwansei Gakuin University, Mita, Hyogo, Japan
| | - Hanna Nishida
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Motomi Hoshino
- College of Biological Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Momoyo Ito
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Fumika Misawa
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | | | - Kenji Miura
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
- College of Biological Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
- Tsukuba Plant-Innovation Research Center, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Masayoshi Kawaguchi
- National Institute for Basic Biology, Okazaki, Aichi, Japan
- School of Life Science, Graduate University for Advanced Studies, Okazaki, Aichi, Japan
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40
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Transcriptome Analysis of Four Arabidopsis thaliana Mediator Tail Mutants Reveals Overlapping and Unique Functions in Gene Regulation. G3-GENES GENOMES GENETICS 2018; 8:3093-3108. [PMID: 30049745 PMCID: PMC6118316 DOI: 10.1534/g3.118.200573] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The Mediator complex is a central component of transcriptional regulation in Eukaryotes. The complex is structurally divided into four modules known as the head, middle, tail and kinase modules, and in Arabidopsis thaliana, comprises 28-34 subunits. Here, we explore the functions of four Arabidopsis Mediator tail subunits, MED2, MED5a/b, MED16, and MED23, by comparing the impact of mutations in each on the Arabidopsis transcriptome. We find that these subunits affect both unique and overlapping sets of genes, providing insight into the functional and structural relationships between them. The mutants primarily exhibit changes in the expression of genes related to biotic and abiotic stress. We find evidence for a tissue specific role for MED23, as well as in the production of alternative transcripts. Together, our data help disentangle the individual contributions of these MED subunits to global gene expression and suggest new avenues for future research into their functions.
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41
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Qi J, Malook SU, Shen G, Gao L, Zhang C, Li J, Zhang J, Wang L, Wu J. Current understanding of maize and rice defense against insect herbivores. PLANT DIVERSITY 2018; 40:189-195. [PMID: 30740564 PMCID: PMC6137261 DOI: 10.1016/j.pld.2018.06.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 06/28/2018] [Accepted: 06/28/2018] [Indexed: 05/25/2023]
Abstract
Plants have sophisticated defense systems to fend off insect herbivores. How plants defend against herbivores in dicotyledonous plants, such as Arabidopsis and tobacco, have been relatively well studied, yet little is known about the defense responses in monocotyledons. Here, we review the current understanding of rice (Oryza sativa) and maize (Zea mays) defense against insects. In rice and maize, elicitors derived from insect herbivore oral secretions or oviposition fluids activate phytohormone signaling, and transcriptomic changes mediated mainly by transcription factors lead to accumulation of defense-related secondary metabolites. Direct defenses, such as trypsin protein inhibitors in rice and benzoxazinoids in maize, have anti-digestive or toxic effects on insect herbivores. Herbivory-induced plant volatiles, such as terpenes, are indirect defenses, which attract the natural enemies of herbivores. R gene-mediated defenses against herbivores are also discussed.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Jianqiang Wu
- Department of Economic Plants and Biotechnology, Yunnan Key Laboratory for Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
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42
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Abstract
Stem cell specification in multicellular organisms relies on the precise spatiotemporal control of RNA polymerase II (Pol II)-dependent gene transcription, in which the evolutionarily conserved Mediator coactivator complex plays an essential role. In Arabidopsis thaliana, SHORTROOT (SHR) and SCARECROW (SCR) orchestrate a transcriptional program that determines the fate and asymmetrical divisions of stem cells generating the root ground tissue. The mechanism by which SHR/SCR relays context-specific regulatory signals to the Pol II general transcription machinery is unknown. Here, we report the role of Mediator in controlling the spatiotemporal transcriptional output of SHR/SCR during asymmetrical division of stem cells and ground tissue patterning. The Mediator subunit MED31 interacted with SCR but not SHR. Reduction of MED31 disrupted the spatiotemporal activation of CYCLIND6;1 (CYCD6;1), leading to defective asymmetrical division of stem cells generating ground tissue. MED31 was recruited to the promoter of CYCD6;1 in an SCR-dependent manner. MED31 was involved in the formation of a dynamic MED31/SCR/SHR ternary complex through the interface protein SCR. We demonstrate that the relative protein abundance of MED31 and SHR in different cell types regulates the dynamic formation of the ternary complex, which provides a tunable switch to strictly control the spatiotemporal transcriptional output. This study provides valuable clues to understand the mechanism by which master transcriptional regulators control organ patterning.
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43
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Crawford T, Lehotai N, Strand Å. The role of retrograde signals during plant stress responses. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:2783-2795. [PMID: 29281071 DOI: 10.1093/jxb/erx481] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 12/11/2017] [Indexed: 05/23/2023]
Abstract
Chloroplast and mitochondria not only provide the energy to the plant cell but due to the sensitivity of organellar processes to perturbations caused by abiotic stress, they are also key cellular sensors of environmental fluctuations. Abiotic stresses result in reduced photosynthetic efficiency and thereby reduced energy supply for cellular processes. Thus, in order to acclimate to stress, plants must re-program gene expression and cellular metabolism to divert energy from growth and developmental processes to stress responses. To restore cellular energy homeostasis following exposure to stress, the activities of the organelles must be tightly co-ordinated with the transcriptional re-programming in the nucleus. Thus, communication between the organelles and the nucleus, so-called retrograde signalling, is essential to direct the energy use correctly during stress exposure. Stress-triggered retrograde signals are mediated by reactive oxygen species and metabolites including β-cyclocitral, MEcPP (2-C-methyl-d-erythritol 2,4-cyclodiphosphate), PAP (3'-phosphoadenosine 5'-phosphate), and intermediates of the tetrapyrrole biosynthesis pathway. However, for the plant cell to respond optimally to environmental stress, these stress-triggered retrograde signalling pathways must be integrated with the cytosolic stress signalling network. We hypothesize that the Mediator transcriptional co-activator complex may play a key role as a regulatory hub in the nucleus, integrating the complex stress signalling networks originating in different cellular compartments.
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Affiliation(s)
- Tim Crawford
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden
| | - Nóra Lehotai
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden
| | - Åsa Strand
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden
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44
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Abstract
Our understanding of the epigenetic mechanisms that regulate gene expression has been largely increased in recent years by the development and refinement of different techniques. This has revealed that gene transcription is highly influenced by epigenetic mechanisms, i.e., those that do not involve changes in the genome sequence, but rather in nuclear architecture, chromosome conformation and histone and DNA modifications. Our understanding of how these different levels of epigenetic regulation interact with each other and with classical transcription-factor based gene regulation to influence gene transcription has just started to emerge. This review discusses the latest advances in unraveling the complex interactions between different types of epigenetic regulation and transcription factor activity, with special attention to the approaches that can be used to study these interactions.
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Affiliation(s)
- Marian Bemer
- Department of Molecular Biology, Wageningen University & Research, Droevendaalsesteeg 1, 6708, PB, Wageningen, The Netherlands.
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45
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Nakayama TJ, Rodrigues FA, Neumaier N, Marcolino-Gomes J, Molinari HBC, Santiago TR, Formighieri EF, Basso MF, Farias JRB, Emygdio BM, de Oliveira ACB, Campos ÂD, Borém A, Harmon FG, Mertz-Henning LM, Nepomuceno AL. Insights into soybean transcriptome reconfiguration under hypoxic stress: Functional, regulatory, structural, and compositional characterization. PLoS One 2017; 12:e0187920. [PMID: 29145496 PMCID: PMC5690659 DOI: 10.1371/journal.pone.0187920] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 10/27/2017] [Indexed: 11/19/2022] Open
Abstract
Soybean (Glycine max) is one of the major crops worldwide and flooding stress affects the production and expansion of cultivated areas. Oxygen is essential for mitochondrial aerobic respiration to supply the energy demand of plant cells. Because oxygen diffusion in water is 10,000 times lower than in air, partial (hypoxic) or total (anoxic) oxygen deficiency is important component of flooding. Even when oxygen is externally available, oxygen deficiency frequently occurs in bulky, dense or metabolically active tissues such as phloem, meristems, seeds, and fruits. In this study, we analyzed conserved and divergent root transcriptional responses between flood-tolerant Embrapa 45 and flood-sensitive BR 4 soybean cultivars under hypoxic stress conditions with RNA-seq. To understand how soybean genes evolve and respond to hypoxia, stable and differentially expressed genes were characterized structurally and compositionally comparing its mechanistic relationship. Between cultivars, Embrapa 45 showed less up- and more down-regulated genes, and stronger induction of phosphoglucomutase (Glyma05g34790), unknown protein related to N-terminal protein myristoylation (Glyma06g03430), protein suppressor of phyA-105 (Glyma06g37080), and fibrillin (Glyma10g32620). RNA-seq and qRT-PCR analysis of non-symbiotic hemoglobin (Glyma11g12980) indicated divergence in gene structure between cultivars. Transcriptional changes for genes in amino acids and derivative metabolic process suggest involvement of amino acids metabolism in tRNA modifications, translation accuracy/efficiency, and endoplasmic reticulum stress in both cultivars under hypoxia. Gene groups differed in promoter TATA box, ABREs (ABA-responsive elements), and CRT/DREs (C-repeat/dehydration-responsive elements) frequency. Gene groups also differed in structure, composition, and codon usage, indicating biological significances. Additional data suggests that cis-acting ABRE elements can mediate gene expression independent of ABA in soybean roots under hypoxia.
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Affiliation(s)
- Thiago J. Nakayama
- Departamento de Fitotecnia, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - Fabiana A. Rodrigues
- Embrapa Soja, Empresa Brasileira de Pesquisa Agropecuária, Londrina, Paraná, Brazil
| | - Norman Neumaier
- Embrapa Soja, Empresa Brasileira de Pesquisa Agropecuária, Londrina, Paraná, Brazil
| | | | - Hugo B. C. Molinari
- Embrapa Agroenergia, Empresa Brasileira de Pesquisa Agropecuária, Brasília, Distrito Federal, Brazil
| | - Thaís R. Santiago
- Embrapa Agroenergia, Empresa Brasileira de Pesquisa Agropecuária, Brasília, Distrito Federal, Brazil
| | - Eduardo F. Formighieri
- Embrapa Agroenergia, Empresa Brasileira de Pesquisa Agropecuária, Brasília, Distrito Federal, Brazil
| | - Marcos F. Basso
- Embrapa Agroenergia, Empresa Brasileira de Pesquisa Agropecuária, Brasília, Distrito Federal, Brazil
| | - José R. B. Farias
- Embrapa Soja, Empresa Brasileira de Pesquisa Agropecuária, Londrina, Paraná, Brazil
| | - Beatriz M. Emygdio
- Embrapa Clima Temperado, Empresa Brasileira de Pesquisa Agropecuária, Pelotas, Rio Grande do Sul, Brazil
| | - Ana C. B. de Oliveira
- Embrapa Clima Temperado, Empresa Brasileira de Pesquisa Agropecuária, Pelotas, Rio Grande do Sul, Brazil
| | - Ângela D. Campos
- Embrapa Clima Temperado, Empresa Brasileira de Pesquisa Agropecuária, Pelotas, Rio Grande do Sul, Brazil
| | - Aluízio Borém
- Departamento de Fitotecnia, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - Frank G. Harmon
- Department of Plant and Microbial Biology, University of California-Berkeley, Berkeley, California, United States of America
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46
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Malik N, Agarwal P, Tyagi A. Emerging functions of multi-protein complex Mediator with special emphasis on plants. Crit Rev Biochem Mol Biol 2017; 52:475-502. [DOI: 10.1080/10409238.2017.1325830] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Naveen Malik
- National Institute of Plant Genome Research (NIPGR), New Delhi, India
| | - Pinky Agarwal
- National Institute of Plant Genome Research (NIPGR), New Delhi, India
| | - Akhilesh Tyagi
- National Institute of Plant Genome Research (NIPGR), New Delhi, India
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, India
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47
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Kazan K. The Multitalented MEDIATOR25. FRONTIERS IN PLANT SCIENCE 2017; 8:999. [PMID: 28659948 PMCID: PMC5467580 DOI: 10.3389/fpls.2017.00999] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 05/26/2017] [Indexed: 05/19/2023]
Abstract
The multi-subunit Mediator complex, which links DNA-bound transcription factors to RNA Pol II during transcription, is an essential regulator of gene expression in all eukaryotes. Individual subunits of the Mediator complex integrate numerous endogenous and exogenous signals. In this paper, diverse regulatory functions performed by MEDIATOR25 (MED25), one of the subunits of the plant Mediator complex are reviewed. MED25 was first identified as a regulator of flowering time and named PHYTOCHROME AND FLOWERING TIME1 (PFT1). Since then, MED25 has been implicated in a range of other plant functions that vary from hormone signaling (JA, ABA, ethylene, and IAA) to biotic and abiotic stress tolerance and plant development. MED25 physically interacts with transcriptional activators (e.g., AP2/ERFs, MYCs, and ARFs), repressors (e.g., JAZs and Aux/IAAs), and other Mediator subunits (MED13 and MED16). In addition, various genetic and epigenetic interactions involving MED25 have been reported. These features make MED25 one of the most multifunctional Mediator subunits and provide new insights into the transcriptional control of gene expression in plants.
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Affiliation(s)
- Kemal Kazan
- Commonwealth Scientific and Industrial Research Organisation Agriculture and Food, BrisbaneQLD, Australia
- Queensland Alliance for Agriculture and Food Innovation, Queensland Bioscience Precinct, The University of Queensland, BrisbaneQLD, Australia
- *Correspondence: Kemal Kazan,
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48
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Toruño TY, Stergiopoulos I, Coaker G. Plant-Pathogen Effectors: Cellular Probes Interfering with Plant Defenses in Spatial and Temporal Manners. ANNUAL REVIEW OF PHYTOPATHOLOGY 2016; 54:419-41. [PMID: 27359369 PMCID: PMC5283857 DOI: 10.1146/annurev-phyto-080615-100204] [Citation(s) in RCA: 379] [Impact Index Per Article: 47.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Plants possess large arsenals of immune receptors capable of recognizing all pathogen classes. To cause disease, pathogenic organisms must be able to overcome physical barriers, suppress or evade immune perception, and derive nutrients from host tissues. Consequently, to facilitate some of these processes, pathogens secrete effector proteins that promote colonization. This review covers recent advances in the field of effector biology, focusing on conserved cellular processes targeted by effectors from diverse pathogens. The ability of effectors to facilitate pathogen entry into the host interior, suppress plant immune perception, and alter host physiology for pathogen benefit is discussed. Pathogens also deploy effectors in a spatial and temporal manner, depending on infection stage. Recent advances have also enhanced our understanding of effectors acting in specific plant organs and tissues. Effectors are excellent cellular probes that facilitate insight into biological processes as well as key points of vulnerability in plant immune signaling networks.
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Affiliation(s)
- Tania Y Toruño
- Department of Plant Pathology, University of California, Davis, California; , ,
| | | | - Gitta Coaker
- Department of Plant Pathology, University of California, Davis, California; , ,
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49
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Malik N, Dwivedi N, Singh AK, Parida SK, Agarwal P, Thakur JK, Tyagi AK. An Integrated Genomic Strategy Delineates Candidate Mediator Genes Regulating Grain Size and Weight in Rice. Sci Rep 2016; 6:23253. [PMID: 27000976 PMCID: PMC4802383 DOI: 10.1038/srep23253] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 03/02/2016] [Indexed: 12/31/2022] Open
Abstract
The present study deployed a Mediator (MED) genes-mediated integrated genomic strategy for understanding the complex genetic architecture of grain size/weight quantitative trait in rice. The targeted multiplex amplicon resequencing of 55 MED genes annotated from whole rice genome in 384 accessions discovered 3971 SNPs, which were structurally and functionally annotated in diverse coding and non-coding sequence-components of genes. Association analysis, using the genotyping information of 3971 SNPs in a structured population of 384 accessions (with 50–100 kb linkage disequilibrium decay), detected 10 MED gene-derived SNPs significantly associated (46% combined phenotypic variation explained) with grain length, width and weight in rice. Of these, one strong grain weight-associated non-synonymous SNP (G/A)-carrying OsMED4_2 gene was validated successfully in low- and high-grain weight parental accessions and homozygous individuals of a rice mapping population. The seed-specific expression, including differential up/down-regulation of three grain size/weight-associated MED genes (including OsMED4_2) in six low and high-grain weight rice accessions was evident. Altogether, combinatorial genomic approach involving haplotype-based association analysis delineated diverse functionally relevant natural SNP-allelic variants in 10 MED genes, including three potential novel SNP haplotypes in an OsMED4_2 gene governing grain size/weight differentiation in rice. These molecular tags have potential to accelerate genomics-assisted crop improvement in rice.
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Affiliation(s)
- Naveen Malik
- National Institute of Plant Genome Research (NIPGR), Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Nidhi Dwivedi
- National Institute of Plant Genome Research (NIPGR), Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Ashok K Singh
- Division of Genetics, Rice Section, Indian Agricultural Research Institute (IARI), New Delhi 110012, India
| | - Swarup K Parida
- National Institute of Plant Genome Research (NIPGR), Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Pinky Agarwal
- National Institute of Plant Genome Research (NIPGR), Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Jitendra K Thakur
- National Institute of Plant Genome Research (NIPGR), Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Akhilesh K Tyagi
- National Institute of Plant Genome Research (NIPGR), Aruna Asaf Ali Marg, New Delhi 110067, India
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