1
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Dong W, Liu L, Sun Y, Xu X, Guo G, Heng W, Jiao H, Wei S, Jia B. PbbHLH155 enhances iron deficiency tolerance in pear by directly activating PbFRO2 and PbbHLH38. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 213:108786. [PMID: 38878387 DOI: 10.1016/j.plaphy.2024.108786] [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: 02/19/2024] [Revised: 05/28/2024] [Accepted: 05/29/2024] [Indexed: 07/07/2024]
Abstract
Iron (Fe) deficiency is a general stress for many horticulture crops, causing leaf chlorosis and stunted growth. The basic-helix-loop-helix (bHLH) transcription factor (TF) was reported to function in Fe absorption; however, the regulatory mechanism of bHLH genes on iron absorption remains largely unclear in pear. In this study, we found that PbbHLH155 was significantly induced by Fe deficiency. Overexpression of PbbHLH155 in Arabidopsis thaliana and pear calli significantly increases resistance to Fe deficiency. The PbbHLH155-overexpressed Arabidopsis lines exhibited greener leaf color, higher Fe content, stronger Fe chelate reductase (FCR) and root acidification activity. The PbbHLH155 knockout pear calli showed lower Fe content and weaker FCR activity. Interestingly, PbbHLH155 inhibited the expressions of PbFRO2 and PbbHLH38, which were positive regulators in Fe-deficiency responses (FDR). Furthermore, yeast one-hybrid (Y1H) and Dual-Luciferase Reporter (DLR) assays revealed that PbbHLH155 directly binds to the promoters of PbFRO2 and PbbHLH38, thus activating their expression. Overall, our results showed that PbbHLH155 directly promote the expression of PbFRO2 and PbbHLH38 to activate FCR activity for iron absorption. This study provided valuable information for pear breeding.
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Affiliation(s)
- Weiyu Dong
- School of Horticulture, Anhui Agricultural University, Hefei, 230036, China.
| | - Lun Liu
- School of Horticulture, Anhui Agricultural University, Hefei, 230036, China.
| | - Yu Sun
- School of Horticulture, Anhui Agricultural University, Hefei, 230036, China.
| | - Xiaoqian Xu
- School of Horticulture, Anhui Agricultural University, Hefei, 230036, China.
| | - Guoling Guo
- School of Horticulture, Anhui Agricultural University, Hefei, 230036, China.
| | - Wei Heng
- School of Horticulture, Anhui Agricultural University, Hefei, 230036, China.
| | - Huijun Jiao
- Shandong Fresh Pear Cultivation and Breeding Engineering Technology Research Center, Shandong Institute of Pomology, Taian, 271000, China.
| | - Shuwei Wei
- Shandong Fresh Pear Cultivation and Breeding Engineering Technology Research Center, Shandong Institute of Pomology, Taian, 271000, China.
| | - Bing Jia
- School of Horticulture, Anhui Agricultural University, Hefei, 230036, China.
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2
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Gao F, Dubos C. The arabidopsis bHLH transcription factor family. TRENDS IN PLANT SCIENCE 2024; 29:668-680. [PMID: 38143207 DOI: 10.1016/j.tplants.2023.11.022] [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: 05/11/2023] [Revised: 11/23/2023] [Accepted: 11/29/2023] [Indexed: 12/26/2023]
Abstract
Basic helix-loop-helices (bHLHs) are present in all eukaryotes and form one of the largest families of transcription factors (TFs) found in plants. bHLHs function as transcriptional activators and/or repressors of genes involved in key processes involved in plant growth and development in interaction with the environment (e.g., stomata and root hair development, iron homeostasis, and response to heat and shade). Recent studies have improved our understanding of the functioning of bHLH TFs in complex regulatory networks where a series of post-translational modifications (PTMs) have critical roles in regulating their subcellular localization, DNA-binding capacity, transcriptional activity, and/or stability (e.g., protein-protein interactions, phosphorylation, ubiquitination, and sumoylation). Further elucidating the function and regulation of bHLHs will help further understanding of the biology of plants in general and for the development of new tools for crop improvement.
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Affiliation(s)
- Fei Gao
- College of Agronomy, Hunan Agricultural University, Changsha 410128, China; Yuelushan Laboratory, Changsha 410128, China.
| | - Christian Dubos
- IPSiM, University of Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France.
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3
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Lei P, Jiang Y, Zhao Y, Jiang M, Ji X, Ma L, Jin G, Li J, Zhang S, Kong D, Zhao X, Meng F. Functions of Basic Helix-Loop-Helix (bHLH) Proteins in the Regulation of Plant Responses to Cold, Drought, Salt, and Iron Deficiency: A Comprehensive Review. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:10692-10709. [PMID: 38712500 DOI: 10.1021/acs.jafc.3c09665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Abiotic stresses including cold, drought, salt, and iron deficiency severely impair plant development, crop productivity, and geographic distribution. Several bodies of research have shed light on the pleiotropic functions of BASIC HELIX-LOOP-HELIX (bHLH) proteins in plant responses to these abiotic stresses. In this review, we mention the regulatory roles of bHLH TFs in response to stresses such as cold, drought, salt resistance, and iron deficiency, as well as in enhancing grain yield in plants, especially crops. The bHLH proteins bind to E/G-box motifs in the target promoter and interact with various other factors to form a complex regulatory network. Through this network, they cooperatively activate or repress the transcription of downstream genes, thereby regulating various stress responses. Finally, we present some perspectives for future research focusing on the molecular mechanisms that integrate and coordinate these abiotic stresses. Understanding these molecular mechanisms is crucial for the development of stress-tolerant crops.
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Affiliation(s)
- Pei Lei
- Jilin Provincial Key Laboratory of Tree and Grass Genetics and Breeding, College of Forestry and Grassland Science, Jilin Agricultural University, Changchun 130118, China
| | - Yaxuan Jiang
- College of Life Science, Northeast Forestry University, Hexing Road 26, Harbin 150040, China
| | - Yong Zhao
- College of Life Sciences, Baicheng Normal University, Baicheng 137099, China
| | - Mingquan Jiang
- Jilin Province Product Quality Supervision and Inspection Institute, Changchun 130022, China
| | - Ximei Ji
- Jilin Provincial Key Laboratory of Tree and Grass Genetics and Breeding, College of Forestry and Grassland Science, Jilin Agricultural University, Changchun 130118, China
- College of Life Science, Northeast Forestry University, Hexing Road 26, Harbin 150040, China
| | - Le Ma
- College of Life Science, Northeast Forestry University, Hexing Road 26, Harbin 150040, China
| | - Guangze Jin
- College of Life Science, Northeast Forestry University, Hexing Road 26, Harbin 150040, China
| | - Jianxin Li
- College of Life Science, Northeast Forestry University, Hexing Road 26, Harbin 150040, China
| | - Subin Zhang
- College of Life Science, Northeast Forestry University, Hexing Road 26, Harbin 150040, China
| | - Dexin Kong
- College of Life Science, Northeast Forestry University, Hexing Road 26, Harbin 150040, China
| | - Xiyang Zhao
- Jilin Provincial Key Laboratory of Tree and Grass Genetics and Breeding, College of Forestry and Grassland Science, Jilin Agricultural University, Changchun 130118, China
| | - Fanjuan Meng
- Jilin Provincial Key Laboratory of Tree and Grass Genetics and Breeding, College of Forestry and Grassland Science, Jilin Agricultural University, Changchun 130118, China
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4
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Cai Y, Ping H, Zhao J, Li C, Li Y, Liang G. IRON MAN interacts with Cu-DEFICIENCY INDUCED TRANSCRIPTION FACTOR 1 to maintain copper homeostasis. THE NEW PHYTOLOGIST 2024; 242:1206-1217. [PMID: 38031525 DOI: 10.1111/nph.19439] [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: 09/26/2023] [Accepted: 11/06/2023] [Indexed: 12/01/2023]
Abstract
Copper (Cu) is essential for plant growth and development. IRON MAN (IMA) is a family of small peptides that can bind both iron (Fe) and Cu ions. It was reported that IMAs mediate Fe homeostasis in Arabidopsis thaliana. However, it remains unclear whether IMAs are involved in Cu homeostasis. The transcript abundance of IMA genes decreased in response to Cu deficiency. The combined disruption of all IMA genes caused enhanced tolerance to Cu deficiency and resulted in an increase in the transcript abundance of Cu uptake genes, whereas the overexpression of IMA1 or IMA3 led to the opposite results. Protein interaction assays indicated that IMAs interact with Cu-DEFICIENCY INDUCED TRANSCRIPTION FACTOR1 (CITF1), which is a positive regulator of the Cu uptake genes. Further studies showed that IMAs not only interfere with the DNA binding of CITF1 but also repress the transcriptional activation activity of CITF1, hence resulting in downregulation of the Cu uptake genes. Genetic analyses indicated that IMAs modulate Cu homeostasis in a CITF1-dependent manner. Our findings indicate that IMAs inhibit the functions of CITF1 in regulating Cu deficiency responses, thereby providing a conceptual framework for comprehending the regulation of Cu homeostasis.
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Affiliation(s)
- Yuerong Cai
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
- Center of Economic Botany, Core Botanical Gardens, Chinese Academy of Sciences, Mengla, Yunnan, 666303, China
| | - Huaqian Ping
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
- Center of Economic Botany, Core Botanical Gardens, Chinese Academy of Sciences, Mengla, Yunnan, 666303, China
| | - Junhui Zhao
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
- Center of Economic Botany, Core Botanical Gardens, Chinese Academy of Sciences, Mengla, Yunnan, 666303, China
| | - Chenyang Li
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
- Center of Economic Botany, Core Botanical Gardens, Chinese Academy of Sciences, Mengla, Yunnan, 666303, China
| | - Yang Li
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
- Center of Economic Botany, Core Botanical Gardens, Chinese Academy of Sciences, Mengla, Yunnan, 666303, China
| | - Gang Liang
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
- Center of Economic Botany, Core Botanical Gardens, Chinese Academy of Sciences, Mengla, Yunnan, 666303, China
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5
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Wang H, Zhao X, Ye Z, Zhu B, Gu L, Du X, Zhu X, Wang H. Topless-related 2 conferred cadmium accumulation in wheat. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 208:108469. [PMID: 38437752 DOI: 10.1016/j.plaphy.2024.108469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 02/05/2024] [Accepted: 02/23/2024] [Indexed: 03/06/2024]
Abstract
Wheat is a vital food crop that faces threats from various abiotic and biotic stresses. Understanding the molecular mechanism of cadmium (Cd) resistance can provide valuable insights into the tolerance of wheat. Plant proteins known as Topless/Topless-Related (TPL/TPR) play a role in growth, development, defense regulation, and stress response. In this study, we identified TaTPR2 as being induced by Cd stress treatment. Upon Cd treatment, wheat plants overexpressing TaTPR2 exhibited better growth compared to wild-type (WT) plants. Moreover, the transgenic lines showed reduced accumulation of reactive oxygen species (ROS), along with significantly higher activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) compared to WT plants. Additionally, the transgenic lines exhibited lower levels of malondialdehyde (MDA) and electrolyte leakage compared to WT plants. Further analysis revealed that TabHLH41 directly binds to the E-box motif of the TaTPR2 promoter and positively regulates its expression. Overall, the overexpression of TaTPR2 in transgenic wheat resulted in reduced accumulation of Cd and ROS. These findings highlight the significance of the TabHLH41-TaTPR2 pathway as a crucial response to Cd stress in wheat.
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Affiliation(s)
- Hongcheng Wang
- School of Life Sciences, Guizhou Normal University, Guiyang, Guizhou Province, China
| | - Xiaosheng Zhao
- School of Life Sciences, Guizhou Normal University, Guiyang, Guizhou Province, China
| | - Zi Ye
- School of Life Sciences, Guizhou Normal University, Guiyang, Guizhou Province, China
| | - Bin Zhu
- School of Life Sciences, Guizhou Normal University, Guiyang, Guizhou Province, China
| | - Lei Gu
- School of Life Sciences, Guizhou Normal University, Guiyang, Guizhou Province, China
| | - Xuye Du
- School of Life Sciences, Guizhou Normal University, Guiyang, Guizhou Province, China
| | - Xiu Zhu
- School of Life Sciences, Guizhou Normal University, Guiyang, Guizhou Province, China.
| | - Huinan Wang
- School of Life Sciences, Guizhou Normal University, Guiyang, Guizhou Province, China.
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6
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Zhang Z, Cheng J, Wang W, Gao Y, Xian X, Li C, Wang Y. Transcription factors dealing with Iron-deficiency stress in plants: focus on the bHLH transcription factor family. PHYSIOLOGIA PLANTARUM 2023; 175:e14091. [PMID: 38148182 DOI: 10.1111/ppl.14091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 10/16/2023] [Accepted: 10/24/2023] [Indexed: 12/28/2023]
Abstract
Iron (Fe), as an important micronutrient element necessary for plant growth and development, not only participates in multiple physiological and biochemical reactions in cells but also exerts a crucial role in respiration and photosynthetic electron transport. Since Fe is mainly present in the soil in the form of iron hydroxide, Fe deficiency exists universally in plants and has become an important factor triggering crop yield reduction and quality decline. It has been shown that transcription factors (TFs), as an important part of plant signaling pathways, not only coordinate the internal signals of different interaction partners during plant development, but also participate in plant responses to biological and abiotic stresses, such as Fe deficiency stress. Here, the role of bHLH transcription factors in the regulation of Fe homeostasis (mainly Fe uptake) is discussed with emphasis on the functions of MYB, WRKY and other TFs in the maintenance of Fe homeostasis. This review provides a theoretical basis for further studies on the regulation of TFs in Fe deficiency stress response.
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Affiliation(s)
- Zhongxing Zhang
- College of Horticulture, Gansu Agricultural University, Lanzhou, China
| | - Jiao Cheng
- College of Horticulture, Gansu Agricultural University, Lanzhou, China
| | - Wanxia Wang
- College of Horticulture, Gansu Agricultural University, Lanzhou, China
| | - Yanlong Gao
- College of Horticulture, Gansu Agricultural University, Lanzhou, China
| | - Xulin Xian
- College of Horticulture, Gansu Agricultural University, Lanzhou, China
| | - Cailong Li
- College of Horticulture, Gansu Agricultural University, Lanzhou, China
| | - Yanxiu Wang
- College of Horticulture, Gansu Agricultural University, Lanzhou, China
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7
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Li X, Cao H, Yu D, Xu K, Zhang Y, Shangguan X, Zheng X, Yang Z, Li C, Pan X, Cui Y, Zhang Z, Han M, Zhang Y, Sun Q, Guo H, Zhao J, Li L, Li C. SlbHLH152, a bHLH transcription factor positively regulates iron homeostasis in tomato. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2023; 335:111821. [PMID: 37558055 DOI: 10.1016/j.plantsci.2023.111821] [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: 04/23/2023] [Revised: 08/03/2023] [Accepted: 08/05/2023] [Indexed: 08/11/2023]
Abstract
The maintain of iron (Fe) homeostasis is essential for plant survival. In tomato, few transcription factors have been identified as regulators of Fe homeostasis, among which SlbHLH068 induced by iron deficiency, plays an important role. However, the upstream regulator(s) responsible for activating the expression of SlbHLH068 remain(s) unknown. In this study, the bHLH (basic helix-loop-helix) transcription factor SlbHLH152 was identified as an upstream regulator of SlbHLH068 using yeast one-hybrid screening. Deletion of SlbHLH152 led to a significant decline in Fe concentration, which was accompanied by reduced expression of Fe-deficiency-responsive genes. In contrast, SlbHLH152 overexpression plants displayed tolerance to iron deficiency, increased Fe accumulation, and elevated expression of Fe-deficiency-responsive genes. Further analysis indicated that SlbHLH152 directly activates the transcription of SlbHLH068. Taken together, our results suggest that SlbHLH152 may be involved in the regulation of iron homeostasis by directly activating the transcription of SlbHLH068 in tomato.
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Affiliation(s)
- Xiaoli Li
- Key Laboratory of Plant Genetics and Molecular Breeding, Zhoukou Normal University, Zhoukou 466001, China; Henan Key Laboratory of Crop Molecular Breeding & Bioreactor, Zhoukou 466001, China
| | - Haohao Cao
- Key Laboratory of Plant Genetics and Molecular Breeding, Zhoukou Normal University, Zhoukou 466001, China; Henan Key Laboratory of Crop Molecular Breeding & Bioreactor, Zhoukou 466001, China
| | - Deshui Yu
- Key Laboratory of Plant Genetics and Molecular Breeding, Zhoukou Normal University, Zhoukou 466001, China; Henan Key Laboratory of Crop Molecular Breeding & Bioreactor, Zhoukou 466001, China
| | - Kedong Xu
- Key Laboratory of Plant Genetics and Molecular Breeding, Zhoukou Normal University, Zhoukou 466001, China; Henan Key Laboratory of Crop Molecular Breeding & Bioreactor, Zhoukou 466001, China
| | - Yi Zhang
- Key Laboratory of Plant Genetics and Molecular Breeding, Zhoukou Normal University, Zhoukou 466001, China; Henan Key Laboratory of Crop Molecular Breeding & Bioreactor, Zhoukou 466001, China
| | - Xinxin Shangguan
- Key Laboratory of Plant Genetics and Molecular Breeding, Zhoukou Normal University, Zhoukou 466001, China; Henan Key Laboratory of Crop Molecular Breeding & Bioreactor, Zhoukou 466001, China
| | - Xiaohong Zheng
- Key Laboratory of Plant Genetics and Molecular Breeding, Zhoukou Normal University, Zhoukou 466001, China; Henan Key Laboratory of Crop Molecular Breeding & Bioreactor, Zhoukou 466001, China
| | - Zhongzhou Yang
- Key Laboratory of Plant Genetics and Molecular Breeding, Zhoukou Normal University, Zhoukou 466001, China; Henan Key Laboratory of Crop Molecular Breeding & Bioreactor, Zhoukou 466001, China
| | - Chaoqiong Li
- College of Life Science and Agronomy, Zhoukou Normal University, Zhoukou 466001, China
| | - Xingchen Pan
- College of Life Science and Agronomy, Zhoukou Normal University, Zhoukou 466001, China
| | - Yiming Cui
- College of Life Science and Agronomy, Zhoukou Normal University, Zhoukou 466001, China
| | - Zhiqing Zhang
- College of Life Science and Agronomy, Zhoukou Normal University, Zhoukou 466001, China
| | - Mengru Han
- College of Life Science and Agronomy, Zhoukou Normal University, Zhoukou 466001, China
| | - Yiqing Zhang
- College of Life Science and Agronomy, Zhoukou Normal University, Zhoukou 466001, China
| | - Qimeng Sun
- College of Life Science and Agronomy, Zhoukou Normal University, Zhoukou 466001, China
| | - Huiling Guo
- College of Life Science and Agronomy, Zhoukou Normal University, Zhoukou 466001, China
| | - Jingyi Zhao
- College of Life Science and Agronomy, Zhoukou Normal University, Zhoukou 466001, China
| | - Lili Li
- Key Laboratory of Plant Genetics and Molecular Breeding, Zhoukou Normal University, Zhoukou 466001, China; Henan Key Laboratory of Crop Molecular Breeding & Bioreactor, Zhoukou 466001, China; College of Life Science and Agronomy, Zhoukou Normal University, Zhoukou 466001, China.
| | - Chengwei Li
- Key Laboratory of Plant Genetics and Molecular Breeding, Zhoukou Normal University, Zhoukou 466001, China; Henan Key Laboratory of Crop Molecular Breeding & Bioreactor, Zhoukou 466001, China; College of Bioengineering, Henan University of Technology, Zhengzhou 450001, China.
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8
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Sun B, Shen Y, Chen S, Shi Z, Li H, Miao X. A novel transcriptional repressor complex MYB22-TOPLESS-HDAC1 promotes rice resistance to brown planthopper by repressing F3'H expression. THE NEW PHYTOLOGIST 2023; 239:720-738. [PMID: 37149887 DOI: 10.1111/nph.18958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 04/13/2023] [Indexed: 05/09/2023]
Abstract
The brown planthopper (BPH) is the most destructive pest of rice. The MYB transcription factors are vital for rice immunity, but most are activators. Although MYB22 positively regulates rice resistance to BPH and has an EAR motif associated with active repression, it remains unclear whether it is a transcriptional repressor affecting rice-BPH interaction. Genetic analyses revealed that MYB22 regulates rice resistance to BPH via its EAR motif. Several biochemical experiments (e.g. transient transcription assay, Y2H, LCA, and BiFC) indicated that MYB22 is a transcriptional repressor that interacts with the corepressor TOPLESS via its EAR motif and recruits HDAC1 to form a tripartite complex. Flavonoid-3'-hydroxylase (F3'H) is a flavonoid biosynthesis pathway-related gene that negatively regulates rice resistance to BPH. Based on a bioinformatics analysis and the results of EMSA and transient transcription assays, MYB22 can bind directly to the F3'H promoter and repress gene expression along with TOPLESS and HDAC1. We revealed a transcriptional regulatory mechanism influencing the rice-BPH interaction that differs from previously reported mechanisms. Specifically, MYB22-TOPLESS-HDAC1 is a novel transcriptional repressor complex with components that synergistically and positively regulate rice resistance to BPH through the transcriptional repression of F3'H.
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Affiliation(s)
- Bo Sun
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 200032, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yanjie Shen
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 200032, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Su Chen
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 200032, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhenying Shi
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 200032, Shanghai, China
| | - Haichao Li
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 200032, Shanghai, China
| | - Xuexia Miao
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 200032, Shanghai, China
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9
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Li J, Nie K, Wang L, Zhao Y, Qu M, Yang D, Guan X. The Molecular Mechanism of GhbHLH121 in Response to Iron Deficiency in Cotton Seedlings. PLANTS (BASEL, SWITZERLAND) 2023; 12:1955. [PMID: 37653872 PMCID: PMC10224022 DOI: 10.3390/plants12101955] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 05/04/2023] [Accepted: 05/08/2023] [Indexed: 09/02/2023]
Abstract
Iron deficiency caused by high pH of saline-alkali soil is a major source of abiotic stress affecting plant growth. However, the molecular mechanism underlying the iron deficiency response in cotton (Gossypium hirsutum) is poorly understood. In this study, we investigated the impacts of iron deficiency at the cotton seedling stage and elucidated the corresponding molecular regulation network, which centered on a hub gene GhbHLH121. Iron deficiency induced the expression of genes with roles in the response to iron deficiency, especially GhbHLH121. The suppression of GhbHLH121 with virus-induced gene silence technology reduced seedlings' tolerance to iron deficiency, with low photosynthetic efficiency and severe damage to the structure of the chloroplast. Contrarily, ectopic expression of GhbHLH121 in Arabidopsis enhanced tolerance to iron deficiency. Further analysis of protein/protein interactions revealed that GhbHLH121 can interact with GhbHLH IVc and GhPYE. In addition, GhbHLH121 can directly activate the expression of GhbHLH38, GhFIT, and GhPYE independent of GhbHLH IVc. All told, GhbHLH121 is a positive regulator of the response to iron deficiency in cotton, directly regulating iron uptake as the upstream gene of GhFIT. Our results provide insight into the complex network of the iron deficiency response in cotton.
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Affiliation(s)
- Jie Li
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Hybrid Cotton R & D Engineering Research Center (the Ministry of Education), College of Agriculture, Nanjing Agricultural University, Nanjing 210095, China;
- Zhejiang Provincial Key Laboratory of Crop Genetic Resources, Institute of Crop Science, Plant Precision Breeding Academy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 300058, China; (K.N.); (L.W.); (Y.Z.)
| | - Ke Nie
- Zhejiang Provincial Key Laboratory of Crop Genetic Resources, Institute of Crop Science, Plant Precision Breeding Academy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 300058, China; (K.N.); (L.W.); (Y.Z.)
- Hainan Institute, Zhejiang University, Yongyou Industry Park, Yazhou Bay Sci-Tech City, Sanya 572000, China
| | - Luyao Wang
- Zhejiang Provincial Key Laboratory of Crop Genetic Resources, Institute of Crop Science, Plant Precision Breeding Academy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 300058, China; (K.N.); (L.W.); (Y.Z.)
- Hainan Institute, Zhejiang University, Yongyou Industry Park, Yazhou Bay Sci-Tech City, Sanya 572000, China
| | - Yongyan Zhao
- Zhejiang Provincial Key Laboratory of Crop Genetic Resources, Institute of Crop Science, Plant Precision Breeding Academy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 300058, China; (K.N.); (L.W.); (Y.Z.)
| | - Mingnan Qu
- Hainan Yazhou Bay Seed Lab, Yazhou Bay Science and Technology City, Yazhou District, Sanya 572025, China;
| | - Donglei Yang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Hybrid Cotton R & D Engineering Research Center (the Ministry of Education), College of Agriculture, Nanjing Agricultural University, Nanjing 210095, China;
| | - Xueying Guan
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Hybrid Cotton R & D Engineering Research Center (the Ministry of Education), College of Agriculture, Nanjing Agricultural University, Nanjing 210095, China;
- Zhejiang Provincial Key Laboratory of Crop Genetic Resources, Institute of Crop Science, Plant Precision Breeding Academy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 300058, China; (K.N.); (L.W.); (Y.Z.)
- Hainan Institute, Zhejiang University, Yongyou Industry Park, Yazhou Bay Sci-Tech City, Sanya 572000, China
- Hainan Yazhou Bay Seed Lab, Yazhou Bay Science and Technology City, Yazhou District, Sanya 572025, China;
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10
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Pu MN, Liang G. The transcription factor POPEYE negatively regulates the expression of bHLH Ib genes to maintain iron homeostasis. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:2754-2767. [PMID: 36787175 PMCID: PMC10797486 DOI: 10.1093/jxb/erad057] [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: 08/25/2022] [Accepted: 02/11/2023] [Indexed: 06/06/2023]
Abstract
Iron (Fe) is an essential trace element for plants. When suffering from Fe deficiency, plants modulate the expression of Fe deficiency-responsive genes to promote Fe uptake. POPEYE (PYE) is a key bHLH (basic helix-loop-helix) transcription factor involved in Fe homeostasis. However, the molecular mechanism of PYE regulating the Fe deficiency response remains elusive in Arabidopsis. We found that the overexpression of PYE attenuates the expression of Fe deficiency-responsive genes. PYE directly represses the transcription of bHLH Ib genes (bHLH38, bHLH39, bHLH100, and bHLH101) by associating with their promoters. Although PYE contains an ethylene response factor-associated amphiphilic repression (EAR) motif, it does not interact with the transcriptional co-repressors TOPLESS/TOPLESS-RELATED (TPL/TPRs). Sub-cellular localization analysis indicated that PYE localizes in both the cytoplasm and nucleus. PYE contains a nuclear export signal (NES) which is required for the cytoplasmic localization of PYE. Mutation of the NES amplifies the repression function of PYE, resulting in down-regulation of Fe deficiency-responsive genes. Co-expression assays indicated that three bHLH IVc members (bHLH104, bHLH105/ILR3, and bHLH115) facilitate the nuclear accumulation of PYE. Conversely, PYE indirectly represses the transcription activation ability of bHLH IVc. Additionally, PYE directly negatively regulates its own transcription. This study provides new insights into the Fe deficiency response signalling pathway and enhances the understanding of PYE functions in Arabidopsis.
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Affiliation(s)
- Meng Na Pu
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Kunming, Yunnan 650223, China
- The College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Gang Liang
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Kunming, Yunnan 650223, China
- The College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
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11
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Song H, Geng Q, Wu X, Hu M, Ye M, Yu X, Chen Y, Xu J, Jiang L, Cao S. The transcription factor MYC1 interacts with FIT to negatively regulate iron homeostasis in Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 114:193-208. [PMID: 36721966 DOI: 10.1111/tpj.16130] [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: 07/07/2022] [Revised: 12/29/2022] [Accepted: 01/24/2023] [Indexed: 06/18/2023]
Abstract
Iron (Fe) is an indispensable trace mineral element for the normal growth of plants, and it is involved in different biological processes; Fe shortage in plants can induce chlorosis and yield loss. The objective of this research is to identify novel genes that participated in the regulation of Fe-deficiency stress in Arabidopsis thaliana. A basic helix-loop-helix (bHLH) transcription factor (MYC1) was identified to be interacting with the FER-LIKE IRON DEFICIENCY-INDUCED TRANSCRIPTION FACTOR (FIT) using a yeast-two-hybrid assay. Transcript-level analysis showed that there was a decrease in MYC1 expression in Arabidopsis to cope with Fe-deficiency stress. Functional deficiency of MYC1 in Arabidopsis leads to an increase in Fe-deficiency tolerance and Fe-accumulation, whereas MYC1-overexpressing plants have an enhanced sensitivity to Fe-deficiency stress. Additionally, MYC1 inhibited the formation of FIT and bHLH38/39 heterodimers, which suppressed the expressed level for Fe acquisition genes FRO2 and IRT1 during Fe-deficiency stress. These results showed that MYC1 functions as a negative modulator of the Fe-deficiency stress response by inhibiting the formation of FIT and bHLH38/39 heterodimers, thereby suppressing the binding of FIT and bHLH38/39 heterodimers to the promoters of FRO2 and IRT1 to modulate Fe intake during Fe-deficiency stress. Overall, the findings of this study elucidated the role of MYC1 in coping with Fe-deficiency stress, and provided potential targets for the developing of crop varieties resistant to Fe-deficiency stress.
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Affiliation(s)
- Hui Song
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Qingliu Geng
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Xi Wu
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Min Hu
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Min Ye
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Xin Yu
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Yifan Chen
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Jiena Xu
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Li Jiang
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Shuqing Cao
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
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12
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Vélez-Bermúdez IC, Schmidt W. Iron sensing in plants. FRONTIERS IN PLANT SCIENCE 2023; 14:1145510. [PMID: 36968364 PMCID: PMC10032465 DOI: 10.3389/fpls.2023.1145510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 02/24/2023] [Indexed: 06/18/2023]
Abstract
The ease of accepting or donating electrons is the raison d'être for the pivotal role iron (Fe) plays in a multitude of vital processes. In the presence of oxygen, however, this very property promotes the formation of immobile Fe(III) oxyhydroxides in the soil, which limits the concentration of Fe that is available for uptake by plant roots to levels well below the plant's demand. To adequately respond to a shortage (or, in the absence of oxygen, a possible surplus) in Fe supply, plants have to perceive and decode information on both external Fe levels and the internal Fe status. As a further challenge, such cues have to be translated into appropriate responses to satisfy (but not overload) the demand of sink (i.e., non-root) tissues. While this seems to be a straightforward task for evolution, the multitude of possible inputs into the Fe signaling circuitry suggests diversified sensing mechanisms that concertedly contribute to govern whole plant and cellular Fe homeostasis. Here, we review recent progress in elucidating early events in Fe sensing and signaling that steer downstream adaptive responses. The emerging picture suggests that Fe sensing is not a central event but occurs in distinct locations linked to distinct biotic and abiotic signaling networks that together tune Fe levels, Fe uptake, root growth, and immunity in an interwoven manner to orchestrate and prioritize multiple physiological readouts.
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Affiliation(s)
| | - Wolfgang Schmidt
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
- Genome and Systems Biology Degree Program, Academia Sinica and National Taiwan University, Taipei, Taiwan
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13
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Lu CK, Liang G. Fe deficiency-induced ethylene synthesis confers resistance to Botrytis cinerea. THE NEW PHYTOLOGIST 2023; 237:1843-1855. [PMID: 36440498 DOI: 10.1111/nph.18638] [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: 05/02/2022] [Accepted: 11/23/2022] [Indexed: 06/16/2023]
Abstract
Although iron (Fe) deficiency is an adverse condition to growth and development of plants, it increases the resistance to pathogens. How Fe deficiency induces the resistance to pathogens is still unclear. Here, we reveal that the inoculation of Botrytis cinerea activates the Fe deficiency response of plants, which further induces ethylene synthesis and then resistance to B. cinerea. FIT and bHLH Ib are a pair of bHLH transcription factors, which control the Fe deficiency response. Both the Fe deficiency-induced ethylene synthesis and resistance are blocked in fit-2 and bhlh4x-1 (a quadruple mutant for four bHLH Ib members). SAM1 and SAM2, two ethylene synthesis-associated genes, are induced by Fe deficiency in a FIT-bHLH Ib-dependent manner. Moreover, SAM1 and SAM2 are required for the increased ethylene and resistance to B. cinerea under Fe-deficient conditions. Our findings suggest that the FIT-bHLH Ib module activates the expression of SAM1 and SAM2, thereby inducing ethylene synthesis and resistance to B. cinerea. This study uncovers that Fe signaling also functions as a part of the plant immune system against pathogens.
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Affiliation(s)
- Cheng Kai Lu
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
- Center of Economic Botany, Core Botanical Gardens, Chinese Academy of Sciences, Menglun, Mengla, Yunnan, 666303, China
| | - Gang Liang
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
- Center of Economic Botany, Core Botanical Gardens, Chinese Academy of Sciences, Menglun, Mengla, Yunnan, 666303, China
- The College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
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14
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Lend Me Your EARs: A Systematic Review of the Broad Functions of EAR Motif-Containing Transcriptional Repressors in Plants. Genes (Basel) 2023; 14:genes14020270. [PMID: 36833197 PMCID: PMC9956375 DOI: 10.3390/genes14020270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 12/22/2022] [Accepted: 01/17/2023] [Indexed: 01/22/2023] Open
Abstract
The ethylene-responsive element binding factor-associated amphiphilic repression (EAR) motif, defined by the consensus sequence patterns LxLxL or DLNx(x)P, is found in a diverse range of plant species. It is the most predominant form of active transcriptional repression motif identified so far in plants. Despite its small size (5 to 6 amino acids), the EAR motif is primarily involved in the negative regulation of developmental, physiological and metabolic functions in response to abiotic and biotic stresses. Through an extensive literature review, we identified 119 genes belonging to 23 different plant species that contain an EAR motif and function as negative regulators of gene expression in various biological processes, including plant growth and morphology, metabolism and homeostasis, abiotic stress response, biotic stress response, hormonal pathways and signalling, fertility, and ripening. Positive gene regulation and transcriptional activation are studied extensively, but there remains much more to be discovered about negative gene regulation and the role it plays in plant development, health, and reproduction. This review aims to fill the knowledge gap and provide insights into the role that the EAR motif plays in negative gene regulation, and provoke further research on other protein motifs specific to repressors.
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15
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Li M, Watanabe S, Gao F, Dubos C. Iron Nutrition in Plants: Towards a New Paradigm? PLANTS (BASEL, SWITZERLAND) 2023; 12:384. [PMID: 36679097 PMCID: PMC9862363 DOI: 10.3390/plants12020384] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 01/10/2023] [Accepted: 01/10/2023] [Indexed: 06/17/2023]
Abstract
Iron (Fe) is an essential micronutrient for plant growth and development. Fe availability affects crops' productivity and the quality of their derived products and thus human nutrition. Fe is poorly available for plant use since it is mostly present in soils in the form of insoluble oxides/hydroxides, especially at neutral to alkaline pH. How plants cope with low-Fe conditions and acquire Fe from soil has been investigated for decades. Pioneering work highlighted that plants have evolved two different strategies to mine Fe from soils, the so-called Strategy I (Fe reduction strategy) and Strategy II (Fe chelation strategy). Strategy I is employed by non-grass species whereas graminaceous plants utilize Strategy II. Recently, it has emerged that these two strategies are not fully exclusive and that the mechanism used by plants for Fe uptake is directly shaped by the characteristics of the soil on which they grow (e.g., pH, oxygen concentration). In this review, recent findings on plant Fe uptake and the regulation of this process will be summarized and their impact on our understanding of plant Fe nutrition will be discussed.
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Affiliation(s)
- Meijie Li
- IPSiM, University Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
| | - Shunsuke Watanabe
- IPSiM, University Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
| | - Fei Gao
- College of Agronomy, Hunan Agricultural University, Changsha 410128, China
| | - Christian Dubos
- IPSiM, University Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
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16
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Wang W, Shinwari KI, Zhang H, Zhang H, Dong L, He F, Zheng L. The bHLH Transcription Factor OsbHLH057 Regulates Iron Homeostasis in Rice. Int J Mol Sci 2022; 23:ijms232314869. [PMID: 36499202 PMCID: PMC9739582 DOI: 10.3390/ijms232314869] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 11/20/2022] [Accepted: 11/23/2022] [Indexed: 11/29/2022] Open
Abstract
Many basic Helix-Loop-Helix (bHLH) transcription factors precisely regulate the expression of Fe uptake and translocation genes to control iron (Fe) homeostasis, as both Fe deficiency and toxicity impair plant growth and development. In rice, three clade IVc bHLH transcription factors have been characterised as positively regulating Fe-deficiency response genes. However, the function of OsbHLH057, another clade IVc bHLH transcription factor, in regulating Fe homeostasis is unknown. Here, we report that OsbHLH057 is involved in regulating Fe homeostasis in rice. OsbHLH057 was highly expressed in the leaf blades and lowly expressed in the roots; it was mainly expressed in the stele and highly expressed in the lateral roots. In addition, OsbHLH057 was slightly induced by Fe deficiency in the shoots on the first day but was not affected by Fe availability in the roots. OsbHLH057 localised in the nucleus exhibited transcriptional activation activity. Under Fe-sufficient conditions, OsbHLH057 knockout or overexpression lines increased or decreased the shoot Fe concentration and the expression of several Fe homeostasis-related genes, respectively. Under Fe-deficient conditions, plants with an OsbHLH057 mutation showed susceptibility to Fe deficiency and accumulated lower Fe concentrations in the shoot compared with the wild type. Unexpectedly, the OsbHLH057-overexpressing lines had reduced tolerance to Fe deficiency. These results indicate that OsbHLH057 plays a positive role in regulating Fe homeostasis, at least under Fe-sufficient conditions.
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17
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Liang G. Iron uptake, signaling, and sensing in plants. PLANT COMMUNICATIONS 2022; 3:100349. [PMID: 35706354 PMCID: PMC9483112 DOI: 10.1016/j.xplc.2022.100349] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 05/19/2022] [Accepted: 06/09/2022] [Indexed: 05/10/2023]
Abstract
Iron (Fe) is an essential micronutrient that affects the growth and development of plants because it participates as a cofactor in numerous physiological and biochemical reactions. As a transition metal, Fe is redox active. Fe often exists in soil in the form of insoluble ferric hydroxides that are not bioavailable to plants. Plants have developed sophisticated mechanisms to ensure an adequate supply of Fe in a fluctuating environment. Plants can sense Fe status and modulate the transcription of Fe uptake-associated genes, finally controlling Fe uptake from soil to root. There is a critical need to understand the molecular mechanisms by which plants maintain Fe homeostasis in response to Fe fluctuations. This review focuses on recent advances in elucidating the functions of Fe signaling components. Taking Arabidopsis thaliana and Oryza sativa as examples, this review begins by discussing the Fe acquisition systems that control Fe uptake from soil, the major components that regulate Fe uptake systems, and the perception of Fe status. Future explorations of Fe signal transduction will pave the way for understanding the regulatory mechanisms that underlie the maintenance of plant Fe homeostasis.
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Affiliation(s)
- Gang Liang
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Kunming, Yunnan 650223, China.
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18
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Li C, Li Y, Xu P, Liang G. OsIRO3 negatively regulates Fe homeostasis by repressing the expression of OsIRO2. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 111:966-978. [PMID: 35689518 DOI: 10.1111/tpj.15864] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Revised: 04/27/2022] [Accepted: 06/07/2022] [Indexed: 06/15/2023]
Abstract
Iron (Fe) is crucial for crop productivity and quality. However, Fe deficiency is prevalent worldwide, particularly in alkaline soil. Plants have evolved sophisticated mechanisms to withstand Fe-deficient conditions. Oryza sativa IRON-RELATED BHLH TRANSCRIPTION FACTOR 3 (OsIRO3/OsbHLH63) has been identified as a negative regulator of Fe deficiency response signaling; however, the underlying mechanism remains unclear. In the present study, we constructed two iro3 mutants, which developed leaves with necrotic lesions under Fe-deficient conditions. Loss-of-function of OsIRO3 caused upregulation of Fe deficiency-associated genes in the root. Fe concentration measurements showed that the iro3 mutants had increased shoot Fe concentration only under Fe-deficient conditions. Further analysis revealed that OsIRO3 directly regulated the expression of IRON-RELATED BHLH TRANSCRIPTION FACTOR 2 (OsIRO2), which encodes a positive regulator of the Fe uptake system. Further investigation demonstrated that OsIRO3 interacted with POSITIVE REGULATOR OF IRON HOMEOSTASIS 1(OsPRI1) and OsPRI2, and. OsIRO3 repressed their transcription activation towards OsIRO2. OsIRO3 contains an EAR motif, which recruits the TOPLESS/TOPLESS-RELATED (OsTPL/OsTPRs) corepressors. Mutation of the EAR motif attenuated the repression ability of OsIRO3. This work sheds light on the molecular mechanism by which OsIRO3 modulates Fe homeostasis in rice.
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Affiliation(s)
- Chenyang Li
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, The Xishuangbanna Tropical Botanical Garden, Innovative Academy of Seed Design, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
- The College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yang Li
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, The Xishuangbanna Tropical Botanical Garden, Innovative Academy of Seed Design, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
- The College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Peng Xu
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, The Xishuangbanna Tropical Botanical Garden, Innovative Academy of Seed Design, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
- The College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Gang Liang
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, The Xishuangbanna Tropical Botanical Garden, Innovative Academy of Seed Design, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
- The College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
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Wang W, Ye J, Xu H, Liu X, Fu Y, Zhang H, Rouached H, Whelan J, Shen Z, Zheng L. OsbHLH061 links TOPLESS/TOPLESS-RELATED repressor proteins with POSITIVE REGULATOR OF IRON HOMEOSTASIS 1 to maintain iron homeostasis in rice. THE NEW PHYTOLOGIST 2022; 234:1753-1769. [PMID: 35288933 DOI: 10.1111/nph.18096] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 02/28/2022] [Indexed: 05/16/2023]
Abstract
As excess iron (Fe) is toxic, uptake of this essential micronutrient must be tightly controlled. Previous studies have shown that Oryza sativa (rice) POSITIVE REGULATOR OF IRON HOMEOSTASIS1 (OsPRI1) acts upstream of the iron-related transcription factor 2 (OsIRO2) and OsIRO3 to positively regulate root-to-shoot Fe translocation. However, as expression of OsPRI1 is constitutive it is unclear how the Fe-deficiency response is turned off to prevent toxicity when Fe is sufficient. The bHLH transcription factor OsbHLH061 interacts with OsPRI1, and this study used molecular, genetics, biochemical and physiological approaches to functionally characterise OsbHLH061 and how it affects Fe homeostasis. OsbHLH061 knockout or overexpression lines increase or decrease Fe accumulation in shoots respectively. Mechanistically, OsbHLH061 expression is upregulated by high Fe, and physically interacts with OsPRI1, the OsbHLH061-OsPRI1 complex recruits TOPLESS/TOPLESS-RELATED (OsTPL/TPR) co-repressors to repress OsIRO2 and OsIRO3 expression. The OsbHLH061 ethylene-responsive element-binding factor-associated amphiphilic repression (EAR) motif is required for this transcriptional repression activity. These results define a functional OsTPL/TPR-OsbHLH061-OsPRI1-OsIRO2/3 module that negatively controls long-distance transport of Fe in plants for adaptation to changing Fe environments and maintain Fe homeostasis in rice.
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Affiliation(s)
- Wujian Wang
- College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
| | - Jun Ye
- College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
| | - Heng Xu
- College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
| | - Xi Liu
- College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
| | - Yue Fu
- College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
| | - Hui Zhang
- College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
| | - Hatem Rouached
- Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI, 48824, USA
| | - James Whelan
- Department of Animal, Plant and Soil Sciences, ARC Centre of Excellence in Plant Energy Biology, School of Life Sciences, La Trobe University, Bundoora, Vic., 3086, Australia
| | - Zhenguo Shen
- College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
| | - Luqing Zheng
- College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
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