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Fujii S, Wada H, Kobayashi K. Orchestration of Photosynthesis-Associated Gene Expression and Galactolipid Biosynthesis during Chloroplast Differentiation in Plants. PLANT & CELL PHYSIOLOGY 2024; 65:1014-1028. [PMID: 38668647 PMCID: PMC11209550 DOI: 10.1093/pcp/pcae049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 04/18/2024] [Accepted: 04/25/2024] [Indexed: 06/28/2024]
Abstract
The chloroplast thylakoid membrane is composed of membrane lipids and photosynthetic protein complexes, and the orchestration of thylakoid lipid biosynthesis and photosynthesis-associated protein accumulation is considered important for thylakoid development. Galactolipids consist of ∼80% of the thylakoid lipids, and their biosynthesis is fundamental for chloroplast development. We previously reported that the suppression of galactolipid biosynthesis decreased the expression of photosynthesis-associated nuclear-encoded genes (PhAPGs) and photosynthesis-associated plastid-encoded genes (PhAPGs). However, the mechanism for coordinative regulation between galactolipid biosynthesis in plastids and the expression of PhANGs and PhAPGs remains largely unknown. To elucidate this mechanism, we investigated the gene expression patterns in galactolipid-deficient Arabidopsis seedlings during the de-etiolation process. We found that galactolipids are crucial for inducing both the transcript accumulation of PhANGs and PhAPGs and the accumulation of plastid-encoded photosynthesis-associated proteins in developing chloroplasts. Genetic analysis indicates the contribution of the GENOMES UNCOUPLED1 (GUN1)-mediated plastid-to-nucleus signaling pathway to PhANG regulation in response to galactolipid levels. Previous studies suggested that the accumulation of GUN1 reflects the state of protein homeostasis in plastids and alters the PhANG expression level. Thus, we propose a model that galactolipid biosynthesis determines the protein homeostasis in plastids in the initial phase of de-etiolation and optimizes GUN1-dependent signaling to regulate the PhANG expression. This mechanism might contribute to orchestrating the biosynthesis of lipids and proteins for the biogenesis of functional chloroplasts in plants.
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Affiliation(s)
- Sho Fujii
- Department of Biology, Faculty of Agriculture and Life Science, Hirosaki University, 3 Bunkyo-cho, Hirosaki, Aomori, 036-8561 Japan
| | - Hajime Wada
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo, 153-8902 Japan
| | - Koichi Kobayashi
- Department of Biology, Graduate School of Science, Osaka Metropolitan University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8531 Japan
- Faculty of Liberal Arts, Science and Global Education, Osaka Metropolitan University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8531 Japan
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Bai A, Zhao T, Li Y, Zhang F, Wang H, Shah SHA, Gong L, Liu T, Wang Y, Hou X, Li Y. QTL mapping and candidate gene analysis reveal two major loci regulating green leaf color in non-heading Chinese cabbage. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2024; 137:105. [PMID: 38622387 DOI: 10.1007/s00122-024-04608-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 03/23/2024] [Indexed: 04/17/2024]
Abstract
KEY MESSAGE Two major-effect QTL GlcA07.1 and GlcA09.1 for green leaf color were fine mapped into 170.25 kb and 191.41 kb intervals on chromosomes A07 and A09, respectively, and were validated by transcriptome analysis. Non-heading Chinese cabbage (NHCC) is a leafy vegetable with a wide range of green colors. Understanding the genetic mechanism behind broad spectrum of green may facilitate the breeding of high-quality NHCC. Here, we used F2 and F7:8 recombination inbred line (RIL) population from a cross between Wutacai (dark-green) and Erqing (lime-green) to undertake the genetic analysis and quantitative trait locus (QTL) mapping in NHCC. The genetic investigation of the F2 population revealed that the variation of green leaf color was controlled by two recessive genes. Six pigments associated with green leaf color, including total chlorophyll, chlorophyll a, chlorophyll b, total carotenoids, lutein, and carotene were quantified and applied for QTL mapping in the RIL population. A total of 7 QTL were detected across the whole genome. Among them, two major-effect QTL were mapped on chromosomes A07 (GlcA07.1) and A09 (GlcA09.1) corresponding to two QTL identified in the F2 population. The QTL GlcA07.1 and GlcA09.1 were further fine mapped into 170.25 kb and 191.41 kb genomic regions, respectively. By comparing gene expression level and gene annotation, BraC07g023810 and BraC07g023970 were proposed as the best candidates for GlcA07.1, while BraC09g052220 and BraC09g052270 were suggested for GlcA09.1. Two InDel molecular markers (GlcA07.1-BcGUN4 and GlcA09.1-BcSG1) associated with BraC07gA023810 and BraC09g052220 were developed and could effectively identify leaf color in natural NHCC accessions, suggesting their potential for marker-assisted leaf color selection in NHCC breeding.
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Affiliation(s)
- Aimei Bai
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and Utilization, Engineering Research Center of Germplasm Enhancement and Utilization of Horticultural Crops, Ministry of Education of the P. R. China, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, Jiangsu Province, China
| | - Tianzi Zhao
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and Utilization, Engineering Research Center of Germplasm Enhancement and Utilization of Horticultural Crops, Ministry of Education of the P. R. China, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, Jiangsu Province, China
| | - Yan Li
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and Utilization, Engineering Research Center of Germplasm Enhancement and Utilization of Horticultural Crops, Ministry of Education of the P. R. China, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, Jiangsu Province, China
| | - Feixue Zhang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and Utilization, Engineering Research Center of Germplasm Enhancement and Utilization of Horticultural Crops, Ministry of Education of the P. R. China, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, Jiangsu Province, China
- Huzhou Academy of Agricultural Sciences, Huzhou, 313000, Zhejiang Province, China
| | - Haibin Wang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and Utilization, Engineering Research Center of Germplasm Enhancement and Utilization of Horticultural Crops, Ministry of Education of the P. R. China, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, Jiangsu Province, China
| | - Sayyed Hamad Ahmad Shah
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and Utilization, Engineering Research Center of Germplasm Enhancement and Utilization of Horticultural Crops, Ministry of Education of the P. R. China, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, Jiangsu Province, China
| | - Li Gong
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and Utilization, Engineering Research Center of Germplasm Enhancement and Utilization of Horticultural Crops, Ministry of Education of the P. R. China, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, Jiangsu Province, China
| | - Tongkun Liu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and Utilization, Engineering Research Center of Germplasm Enhancement and Utilization of Horticultural Crops, Ministry of Education of the P. R. China, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, Jiangsu Province, China
| | - Yuhui Wang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and Utilization, Engineering Research Center of Germplasm Enhancement and Utilization of Horticultural Crops, Ministry of Education of the P. R. China, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, Jiangsu Province, China.
| | - Xilin Hou
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and Utilization, Engineering Research Center of Germplasm Enhancement and Utilization of Horticultural Crops, Ministry of Education of the P. R. China, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, Jiangsu Province, China
| | - Ying Li
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and Utilization, Engineering Research Center of Germplasm Enhancement and Utilization of Horticultural Crops, Ministry of Education of the P. R. China, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, Jiangsu Province, China.
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Sun M, Shen Y. Integrating the multiple functions of CHLH into chloroplast-derived signaling fundamental to plant development and adaptation as well as fruit ripening. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2024; 338:111892. [PMID: 37821024 DOI: 10.1016/j.plantsci.2023.111892] [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: 04/12/2023] [Revised: 10/01/2023] [Accepted: 10/06/2023] [Indexed: 10/13/2023]
Abstract
Chlorophyll (Chl)-mediated oxygenic photosynthesis sustains life on Earth. Greening leaves play fundamental roles in plant growth and crop yield, correlating with the idea that more Chls lead to better adaptation. However, they face significant challenges from various unfavorable environments. Chl biosynthesis hinges on the first committed step, which involves inserting Mg2+ into protoporphyrin. This step is facilitated by the H subunit of magnesium chelatase (CHLH) and features a conserved mechanism from cyanobacteria to plants. For better adaptation to fluctuating land environments, especially drought, CHLH evolves multiple biological functions, including Chl biosynthesis, retrograde signaling, and abscisic acid (ABA) responses. Additionally, it integrates into various chloroplast-derived signaling pathways, encompassing both retrograde signaling and hormonal signaling. The former comprises ROS (reactive oxygen species), heme, GUN (genomes uncoupled), MEcPP (methylerythritol cyclodiphosphate), β-CC (β-cyclocitral), and PAP (3'-phosphoadenosine-5'-phosphate). The latter involves phytohormones like ABA, ethylene, auxin, cytokinin, gibberellin, strigolactone, brassinolide, salicylic acid, and jasmonic acid. Together, these elements create a coordinated regulatory network tailored to plant development and adaptation. An intriguing example is how drought-mediated improvement of fruit quality provides insights into chloroplast-derived signaling, aiding the shift from vegetative to reproductive growth. In this context, we explore the integration of CHLH's multifaceted roles into chloroplast-derived signaling, which lays the foundation for plant development and adaptation, as well as fruit ripening and quality. In the future, manipulating chloroplast-derived signaling may offer a promising avenue to enhance crop yield and quality through the homeostasis, function, and regulation of Chls.
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Affiliation(s)
- Mimi Sun
- College of Horticulture, China Agricultural University, Beijing 100193, China; College of Plant Science and Technology, Beijing University of Agriculture, 7 Beinong Road, Changping District, Beijing 102206, China
| | - Yuanyue Shen
- College of Plant Science and Technology, Beijing University of Agriculture, 7 Beinong Road, Changping District, Beijing 102206, China.
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Ji S, Grimm B, Wang P. Chloroplast SRP43 and SRP54 independently promote thermostability and membrane binding of light-dependent protochlorophyllide oxidoreductases. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 115:1583-1598. [PMID: 37269173 DOI: 10.1111/tpj.16339] [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: 02/22/2023] [Revised: 04/18/2023] [Accepted: 05/22/2023] [Indexed: 06/04/2023]
Abstract
Protochlorophyllide oxidoreductase (POR), which converts protochlorophyllide into chlorophyllide, is the only light-dependent enzyme in chlorophyll biosynthesis. While its catalytic reaction and importance for chloroplast development are well understood, little is known about the post-translational control of PORs. Here, we show that cpSRP43 and cpSRP54, two components of the chloroplast signal recognition particle pathway, play distinct roles in optimizing the function of PORB, the predominant POR isoform in Arabidopsis. The chaperone cpSRP43 stabilizes the enzyme and provides appropriate amounts of PORB during leaf greening and heat shock, whereas cpSRP54 enhances its binding to the thylakoid membrane, thereby ensuring adequate levels of metabolic flux in late chlorophyll biosynthesis. Furthermore, cpSRP43 and the DnaJ-like protein CHAPERONE-LIKE PROTEIN of POR1 concurrently act to stabilize PORB. Overall, these findings enhance our understanding of the coordinating role of cpSPR43 and cpSRP54 in the post-translational control of chlorophyll synthesis and assembly of photosynthetic chlorophyll-binding proteins.
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Affiliation(s)
- Shuiling Ji
- Institute of Biology/Plant Physiology, Humboldt-Universität zu Berlin, Philippstr.13, Building 12, 10099, Berlin, Germany
- School of Life Sciences, Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University, 430079, Wuhan, China
| | - Bernhard Grimm
- Institute of Biology/Plant Physiology, Humboldt-Universität zu Berlin, Philippstr.13, Building 12, 10099, Berlin, Germany
| | - Peng Wang
- Institute of Biology/Plant Physiology, Humboldt-Universität zu Berlin, Philippstr.13, Building 12, 10099, Berlin, Germany
- School of Biological Sciences, The University of Hong Kong, Hong Kong, 999077, China
- State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, 999077, Hong Kong, China
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Zhang M, Shen J, Wu Y, Zhang X, Zhao Z, Wang J, Cheng T, Zhang Q, Pan H. Comparative transcriptome analysis identified ChlH and POLGAMMA2 in regulating yellow-leaf coloration in Forsythia. FRONTIERS IN PLANT SCIENCE 2022; 13:1009575. [PMID: 36160960 PMCID: PMC9501713 DOI: 10.3389/fpls.2022.1009575] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 08/24/2022] [Indexed: 05/24/2023]
Abstract
Leaf color is one of the most important features for plants used for landscape and ornamental purposes. However, the regulatory mechanism of yellow leaf coloration still remains elusive in many plant species. To understand the complex genetic mechanism of yellow-leaf Forsythia, we first compared the pigment content and leaf anatomical structure of yellow-leaf and green-leaf accessions derived from a hybrid population. The physiological and cytological analyses demonstrated that yellow-leaf progenies were chlorophyll deficient with defected chloroplast structure. With comparative transcriptome analysis, we identified a number of candidate genes differentially expressed between yellow-leaf and green-leaf Forsythia plants. Among these genes, we further screened out two candidates, ChlH (magnesium chelatase Subunit H) and POLGAMMA2 (POLYMERASE GAMMA 2), with consistent relative-expression pattern between different colored plants. To verify the gene function, we performed virus-induced gene silencing assays and observed yellow-leaf phenotype with total chlorophyll content reduced by approximately 66 and 83% in ChlH-silenced and POLGAMMA2-silenced plants, respectively. We also observed defected chloroplast structure in both ChlH-silenced and POLGAMMA2-silenced Forsythia. Transient over-expression of ChlH and POLGAMMA2 led to increased chlorophyll content and restored thylakoid architecture in yellow-leaf Forsythia. With transcriptome sequencing, we detected a number of genes related to chlorophyll biosynthesis and chloroplast development that were responsive to the silencing of ChlH and POLGAMMA2. To summarize, ChlH and POLGAMMA2 are two key genes that possibly related to yellow-leaf coloration in Forsythia through modulating chlorophyll synthesis and chloroplast ultrastructure. Our study provided insights into the molecular aspects of yellow-leaf Forsythia and expanded the knowledge of foliage color regulation in woody ornamental plants.
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Affiliation(s)
- Man Zhang
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, College of Landscape Architecture, Beijing Forestry University, Beijing, China
| | - Jianshuang Shen
- Department of Landscape Architecture, Jiyang College, Zhejiang A&F University, Zhuji, China
| | - Yutong Wu
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, College of Landscape Architecture, Beijing Forestry University, Beijing, China
| | - Xiaolu Zhang
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, College of Landscape Architecture, Beijing Forestry University, Beijing, China
| | - Zhengtian Zhao
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, College of Landscape Architecture, Beijing Forestry University, Beijing, China
| | - Jia Wang
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, College of Landscape Architecture, Beijing Forestry University, Beijing, China
| | - Tangren Cheng
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, College of Landscape Architecture, Beijing Forestry University, Beijing, China
| | - Qixiang Zhang
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, College of Landscape Architecture, Beijing Forestry University, Beijing, China
| | - Huitang Pan
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, College of Landscape Architecture, Beijing Forestry University, Beijing, China
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Fölsche V, Großmann C, Richter AS. Impact of Porphyrin Binding to GENOMES UNCOUPLED 4 on Tetrapyrrole Biosynthesis in planta. FRONTIERS IN PLANT SCIENCE 2022; 13:850504. [PMID: 35371166 PMCID: PMC8967248 DOI: 10.3389/fpls.2022.850504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 02/16/2022] [Indexed: 06/14/2023]
Abstract
Plant tetrapyrrole biosynthesis (TPS) provides the indispensable chlorophyll (Chl) and heme molecules in photosynthetic organisms. Post-translational mechanisms control the enzymes to ensure a balanced flow of intermediates in the pathway and synthesis of appropriate amounts of both endproducts. One of the critical regulators of TPS is GENOMES UNCOUPLED 4 (GUN4). GUN4 interacts with magnesium chelatase (MgCh), and its binding of the catalytic substrate and product of the MgCh reaction stimulates the insertion of Mg2+ into protoporphyrin IX. Despite numerous in vitro studies, knowledge about the in vivo function of the GUN4:porphyrin interaction for the whole TPS pathway, particularly in plants, is still limited. To address this, we focused on two highly conserved amino acids crucial for porphyrin-binding to GUN4 and analyzed GUN4-F191A, R211A, and R211E substitution mutants in vitro and in vivo. Our analysis confirmed the importance of these amino acids for porphyrin-binding and the stimulation of plant MgCh by GUN4 in vitro. Expression of porphyrin-binding deficient F191A, R211A, and R211E in the Arabidopsis gun4-2 knockout mutant background revealed that, unlike in cyanobacteria and green algae, GUN4:porphyrin interactions did not affect the stability of GUN4 or other Arabidopsis TPS pathway enzymes in vivo. In addition, although they shared diminished porphyrin-binding and MgCh activation in vitro, expression of the different GUN4 mutants in gun4-2 had divergent effects on the TPS and the accumulation of Chl and Chl-binding proteins. For instance, expression of R211E, but not R211A, induced a substantial decrease of ALA synthesis rate, lower TPS intermediate and Chl level, and strongly impaired accumulation of photosynthetic complexes compared to wild-type plants. Furthermore, the presence of R211E led to significant growth retardation and paler leaves compared to GUN4 knockdown mutants, indicating that the exchange of R211 to glutamate compromised TPS and Chl accumulation more substantially than the almost complete lack of GUN4. Extensive in vivo analysis of GUN4 point mutants suggested that F191 and R211 might also play a role beyond porphyrin-binding.
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Affiliation(s)
- Vincent Fölsche
- Physiology of Plant Cell Organelles, Humboldt-Universität Berlin, Berlin, Germany
- Department of Plant Physiology, Humboldt-Universität Berlin, Berlin, Germany
| | - Christopher Großmann
- Physiology of Plant Cell Organelles, Humboldt-Universität Berlin, Berlin, Germany
| | - Andreas S. Richter
- Physiology of Plant Cell Organelles, Humboldt-Universität Berlin, Berlin, Germany
- Department of Plant Physiology, Humboldt-Universität Berlin, Berlin, Germany
- Physiology of Plant Metabolism, University of Rostock, Rostock, Germany
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Shimizu T, Masuda T. The Role of Tetrapyrrole- and GUN1-Dependent Signaling on Chloroplast Biogenesis. PLANTS 2021; 10:plants10020196. [PMID: 33494334 PMCID: PMC7911674 DOI: 10.3390/plants10020196] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 01/15/2021] [Accepted: 01/18/2021] [Indexed: 12/14/2022]
Abstract
Chloroplast biogenesis requires the coordinated expression of the chloroplast and nuclear genomes, which is achieved by communication between the developing chloroplasts and the nucleus. Signals emitted from the plastids, so-called retrograde signals, control nuclear gene expression depending on plastid development and functionality. Genetic analysis of this pathway identified a set of mutants defective in retrograde signaling and designated genomes uncoupled (gun) mutants. Subsequent research has pointed to a significant role of tetrapyrrole biosynthesis in retrograde signaling. Meanwhile, the molecular functions of GUN1, the proposed integrator of multiple retrograde signals, have not been identified yet. However, based on the interactions of GUN1, some working hypotheses have been proposed. Interestingly, GUN1 contributes to important biological processes, including plastid protein homeostasis, through transcription, translation, and protein import. Furthermore, the interactions of GUN1 with tetrapyrroles and their biosynthetic enzymes have been revealed. This review focuses on our current understanding of the function of tetrapyrrole retrograde signaling on chloroplast biogenesis.
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Li J, Zhang F, Li Y, Yang W, Lin R. Chloroplast-Localized Protoporphyrinogen IX Oxidase1 Is Involved in the Mitotic Cell Cycle in Arabidopsis. PLANT & CELL PHYSIOLOGY 2019; 60:2436-2448. [PMID: 31350548 DOI: 10.1093/pcp/pcz135] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 07/04/2019] [Indexed: 06/10/2023]
Abstract
Protoporphyrinogen IX oxidase1 (PPO1) catalyzes the oxidation of protoporphyrinogen IX to form protoporphyrin IX in the plastid tetrapyrrole biosynthesis pathway and is also essential for plastid RNA editing in Arabidopsis thaliana. The Arabidopsis ppo1-1 mutation was previously shown to be seedling lethal; however, in this study, we showed that the heterozygous ppo1-1/+ mutant exhibited reproductive growth defects characterized by reduced silique length and seed set, as well as aborted pollen development. In this mutant, the second mitotic division was blocked during male gametogenesis, whereas female gametogenesis was impaired at the one-nucleate stage. Before perishing at the seedling stage, the homozygous ppo1-1 mutant displayed reduced hypocotyl and root length, increased levels of reactive oxygen species accumulation and elevated cell death, especially under light conditions. Wild-type seedlings treated with acifluorfen, a PPO1 inhibitor, showed similar phenotypes to the ppo1-1 mutants, and both plants possessed a high proportion of 2C nuclei and a low proportion of 8C nuclei compared with the untreated wild type. Genome-wide RNA-seq analysis showed that a number of genes, including cell cycle-related genes, were differentially regulated by PPO1. Consistently, PPO1 was highly expressed in the pollen, anther, pistil and root apical meristem cells actively undergoing cell division. Our study reveals a role for PPO1 involved in the mitotic cell cycle during gametogenesis and seedling development.
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Affiliation(s)
- Jialong Li
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Fan Zhang
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Yuhong Li
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Weicai Yang
- University of Chinese Academy of Sciences, Beijing, China
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Rongcheng Lin
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
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9
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Liang Y, Kang K, Gan L, Ning S, Xiong J, Song S, Xi L, Lai S, Yin Y, Gu J, Xiang J, Li S, Wang B, Li M. Drought-responsive genes, late embryogenesis abundant group3 (LEA3) and vicinal oxygen chelate, function in lipid accumulation in Brassica napus and Arabidopsis mainly via enhancing photosynthetic efficiency and reducing ROS. PLANT BIOTECHNOLOGY JOURNAL 2019; 17:2123-2142. [PMID: 30972883 PMCID: PMC6790364 DOI: 10.1111/pbi.13127] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 03/18/2019] [Accepted: 04/04/2019] [Indexed: 05/10/2023]
Abstract
Drought is an abiotic stress that affects plant growth, and lipids are the main economic factor in the agricultural production of oil crops. However, the molecular mechanisms of drought response function in lipid metabolism remain little known. In this study, overexpression (OE) of different copies of the drought response genes LEA3 and VOC enhanced both drought tolerance and oil content in Brassica napus and Arabidopsis. Meanwhile, seed size, membrane stability and seed weight were also improved in OE lines. In contrast, oil content and drought tolerance were decreased in the AtLEA3 mutant (atlea3) and AtVOC-RNAi of Arabidopsis and in both BnLEA-RNAi and BnVOC-RNAi B. napus RNAi lines. Hybrids between two lines with increased or reduced expression (LEA3-OE with VOC-OE, atlea3 with AtVOC-RNAi) showed corresponding stronger trends in drought tolerance and lipid metabolism. Comparative transcriptomic analysis revealed the mechanisms of drought response gene function in lipid accumulation and drought tolerance. Gene networks involved in fatty acid (FA) synthesis and FA degradation were up- and down-regulated in OE lines, respectively. Key genes in the photosynthetic system and reactive oxygen species (ROS) metabolism were up-regulated in OE lines and down-regulated in atlea3 and AtVOC-RNAi lines, including LACS9, LIPASE1, PSAN, LOX2 and SOD1. Further analysis of photosynthetic and ROS enzymatic activities confirmed that the drought response genes LEA3 and VOC altered lipid accumulation mainly via enhancing photosynthetic efficiency and reducing ROS. The present study provides a novel way to improve lipid accumulation in plants, especially in oil production crops.
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Affiliation(s)
- Yu Liang
- Department of BiotechnologyCollege of Life Science and TechnologyHuazhong University of Science and TechnologyWuhanChina
| | - Kai Kang
- Department of BiotechnologyCollege of Life Science and TechnologyHuazhong University of Science and TechnologyWuhanChina
| | - Lu Gan
- Center for Plant Science Innovation and Department of BiochemistryUniversity of Nebraska LincolnLincolnNEUSA
| | - Shaobo Ning
- Department of BiotechnologyCollege of Life Science and TechnologyHuazhong University of Science and TechnologyWuhanChina
| | - Jinye Xiong
- Department of BiotechnologyCollege of Life Science and TechnologyHuazhong University of Science and TechnologyWuhanChina
| | - Shuyao Song
- Department of BiotechnologyCollege of Life Science and TechnologyHuazhong University of Science and TechnologyWuhanChina
| | - Lingzhi Xi
- Department of BiotechnologyCollege of Life Science and TechnologyHuazhong University of Science and TechnologyWuhanChina
| | - Senying Lai
- Department of BiotechnologyCollege of Life Science and TechnologyHuazhong University of Science and TechnologyWuhanChina
| | - Yongtai Yin
- Department of BiotechnologyCollege of Life Science and TechnologyHuazhong University of Science and TechnologyWuhanChina
| | - Jianwei Gu
- Hubei Research Institute of New Socialist Countryside DevelopmentHubei Engineering UniversityXiaoganChina
| | - Jun Xiang
- Hubei Key Laboratory of Economic Forest Germplasm Improvement and Resources Comprehensive UtilizationHubei Collaborative Innovation Center for the Characteristic Resources Exploitation of Dabie MountainsHuanggang Normal UniversityHuanggangChina
| | - Shisheng Li
- Hubei Key Laboratory of Economic Forest Germplasm Improvement and Resources Comprehensive UtilizationHubei Collaborative Innovation Center for the Characteristic Resources Exploitation of Dabie MountainsHuanggang Normal UniversityHuanggangChina
| | - Baoshan Wang
- College of Life ScienceShandong Normal UniversityJinanChina
| | - Maoteng Li
- Department of BiotechnologyCollege of Life Science and TechnologyHuazhong University of Science and TechnologyWuhanChina
- Hubei Key Laboratory of Economic Forest Germplasm Improvement and Resources Comprehensive UtilizationHubei Collaborative Innovation Center for the Characteristic Resources Exploitation of Dabie MountainsHuanggang Normal UniversityHuanggangChina
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10
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Pheomphun P, Treesubsuntorn C, Thiravetyan P. Effect of exogenous catechin on alleviating O 3 stress: The role of catechin-quinone in lipid peroxidation, salicylic acid, chlorophyll content, and antioxidant enzymes of Zamioculcas zamiifolia. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 180:374-383. [PMID: 31102845 DOI: 10.1016/j.ecoenv.2019.05.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 04/27/2019] [Accepted: 05/01/2019] [Indexed: 05/20/2023]
Abstract
Ozone (O3) can cause oxidative stress in plants and humans. Catechin is an antioxidant that enriches tea and can probably increase O3 tolerance in plants. To investigate the mechanism of catechin to alleviate O3 stress in plants, Zamiocalcus zamiifolia (an efficient plant for O3 phytoremediation) was sprayed with 5 mM catechin and was used to expose O3 (150-250) under long-term operation (10 cycles). We investigated whether exogenous catechin could enhance O3 removal and alleviate O3 stress through a balanced redox state in plants. Z. zamiifolia sprayed with catechin exhibited higher O3 removal (80.27±3.12%), than Z. zamiifolia without catechin (50.03±2.68%). O3 in the range of 150-250 ppb led to stress in plants, as shown by an increased malondialdehyde content (MDA) and salicylic acid (SA). Whereas under the presence of O3, exogenous catechin could maintain the MDA content and inhibit SA accumulation. Under Z. zamiifolia+catechin+O3 conditions, catechin reacted with O3, which led to the formation of catechin-quinone. The formation of catechin-quinone was confirmed by the depletion of reduced glutathione content (GSH). This catechin-quinone could induce GST and APX genes that are up-regulated approximately 35- and 5-fold, respectively. Hence, Z. zamiifolia+catechin+O3 conditions had higher performance for coping with oxidative stress than did Z. zamiifolia+O3 conditions. This evidence demonstrates that catechin could enhance O3 removal through a balanced redox state in plant cells. Finally, the application of tea extract for enhanced O3 removal is also shown in this study.
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Affiliation(s)
- Piyatida Pheomphun
- School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, Bangkok, 10150, Thailand
| | - Chairat Treesubsuntorn
- Pilot Plant Development and Training Institute, King Mongkut's University of Technology Thonburi, Bangkok, 10150, Thailand
| | - Paitip Thiravetyan
- School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, Bangkok, 10150, Thailand.
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11
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Wu W, Liu LL, Yang T, Wang JH, Wang JY, Lv P, Yan YC. Gene expression analysis reveals function of TERF1 in plastid-nucleus retrograde signaling under drought stress conditions. BIOLOGIA PLANTARUM 2018. [PMID: 0 DOI: 10.1007/s10535-018-0771-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
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12
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Genetic Analysis of Chloroplast Biogenesis, and Function and Mutant Collections. Methods Mol Biol 2018. [PMID: 29987733 DOI: 10.1007/978-1-4939-8654-5_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Since the time DNA was discovered as the code of life, genetic analysis has greatly advanced our understanding of the relation between genotype and phenotype and associated molecular mechanisms in various organisms including plants and algae. Forward genetics from phenotype to genotype has identified causal genes of interesting phenotypes induced by chemical, ionizing-radiation, or DNA insertional mutagenesis. Meanwhile, reverse genetics from genotype to phenotype has revealed physiological and molecular roles of known gene sequences. During the past dozen years, many molecular genetic tools have been developed to investigate gene functions quickly and efficiently. In this chapter, we introduce several approaches of forward and reverse genetics, including random chemical and DNA insertional mutagenesis, activation tagging, RNA interference, and gene overexpression and induction systems, with some examples of genetic studies of chloroplast biology mainly in Arabidopsis thaliana. We also briefly describe methods for chemical and DNA insertion mutagenesis and how to obtain sequence-tagged mutants from public collections. With greatly improved DNA sequencing and genome-editing technologies, model organisms as well as diverse species can be used for molecular biology. Genetic analysis can play an increasingly important role in elucidating chloroplast biogenesis and functions.
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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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Water-stress induced downsizing of light-harvesting antenna complex protects developing rice seedlings from photo-oxidative damage. Sci Rep 2018; 8:5955. [PMID: 29654242 PMCID: PMC5899091 DOI: 10.1038/s41598-017-14419-4] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 10/11/2017] [Indexed: 12/11/2022] Open
Abstract
The impact of water-stress on chloroplast development was studied by applying polyethylene glycol 6000 to the roots of 5-day-old etiolated rice (Oryza sativa) seedlings that were subsequently illuminated up to 72 h. Chloroplast development in drought environment led to down-regulation of light-harvesting Chl-proteins. Photosynthetic proteins of Photosystem II (PSII) and oxygen evolving complex i.e., Cytb559, OEC16, OEC23 and OEC33 as well as those of PSI such as PSI-III, PSI-V, and PSI-VI, decreased in abundance. Consequently, due to reduced light absorption by antennae, the electron transport rates of PSII and PSI decreased by 55% and 25% respectively. Further, seedling development in stress condition led to a decline in the ratio of variable (Fv) to maximum (Fm) Chl a fluorescence, as well in the quantum yield of PSII photochemistry. Addition of Mg2+ to the thylakoid membranes suggested that Mg2+-induced grana stacking was not affected by water deficit. Proteomic analysis revealed the down-regulation of proteins involved in electron transport and in carbon reduction reactions, and up-regulation of antioxidative enzymes. Our results demonstrate that developing seedlings under water deficit could downsize their light-harvesting capacity and components of photosynthetic apparatus to prevent photo-oxidative stress, excess ROS generation and membrane lipid peroxidation.
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Da Q, Sun T, Wang M, Jin H, Li M, Feng D, Wang J, Wang HB, Liu B. M-type thioredoxins are involved in the xanthophyll cycle and proton motive force to alter NPQ under low-light conditions in Arabidopsis. PLANT CELL REPORTS 2018; 37:279-291. [PMID: 29080907 DOI: 10.1007/s00299-017-2229-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 10/18/2017] [Indexed: 06/07/2023]
Abstract
M-type thioredoxins are required to regulate zeaxanthin epoxidase activity and to maintain the steady-state level of the proton motive force, thereby influencing NPQ properties under low-light conditions in Arabidopsis. Non-photochemical quenching (NPQ) helps protect photosynthetic organisms from photooxidative damage via the non-radiative dissipation of energy as heat. Energy-dependent quenching (qE) is a major constituent of NPQ. However, the mechanism underlying the regulation of qE is not well understood. In this study, we demonstrate that the m-type thioredoxins TRX-m1, TRX-m2, and TRX-m4 (TRX-ms) interact with the xanthophyll cycle enzyme zeaxanthin epoxidase (ZE) and are required for maintaining the redox-dependent stabilization of ZE by regulating its intermolecular disulfide bridges. Reduced ZE activity and accumulated zeaxanthin levels were observed under TRX-ms deficiency. Furthermore, concurrent deficiency of TRX-ms resulted in a significant increase in proton motive force (pmf) and acidification of the thylakoid lumen under low irradiance, perhaps due to the significantly reduced ATP synthase activity under TRX-ms deficiency. The increased pmf, combined with acidification of the thylakoid lumen and the accumulation of zeaxanthin, ultimately contribute to the elevated stable qE in VIGS-TRX-m2m4/m1 plants under low-light conditions. Taken together, these results indicate that TRX-ms are involved in regulating NPQ-dependent photoprotection in Arabidopsis.
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Affiliation(s)
- Qingen Da
- State Key Laboratory of Biocontrol and Collaborative Innovation Center of Genetics and Development, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, People's Republic of China
| | - Ting Sun
- State Key Laboratory of Biocontrol and Collaborative Innovation Center of Genetics and Development, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, People's Republic of China
| | - Menglong Wang
- State Key Laboratory of Biocontrol and Collaborative Innovation Center of Genetics and Development, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, People's Republic of China
| | - Honglei Jin
- State Key Laboratory of Biocontrol and Collaborative Innovation Center of Genetics and Development, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, People's Republic of China
| | - Mengshu Li
- State Key Laboratory of Biocontrol and Collaborative Innovation Center of Genetics and Development, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, People's Republic of China
| | - Dongru Feng
- State Key Laboratory of Biocontrol and Collaborative Innovation Center of Genetics and Development, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, People's Republic of China
| | - Jinfa Wang
- State Key Laboratory of Biocontrol and Collaborative Innovation Center of Genetics and Development, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, People's Republic of China
| | - Hong-Bin Wang
- State Key Laboratory of Biocontrol and Collaborative Innovation Center of Genetics and Development, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, People's Republic of China
| | - Bing Liu
- State Key Laboratory of Biocontrol and Collaborative Innovation Center of Genetics and Development, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, People's Republic of China.
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Li X, He Y, Yang J, Jia YH, Zeng HL. Gene mapping and transcriptome profiling of a practical photo-thermo-sensitive rice male sterile line with seedling-specific green-revertible albino leaf. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2018; 266:37-45. [PMID: 29241565 DOI: 10.1016/j.plantsci.2017.10.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Revised: 09/20/2017] [Accepted: 10/20/2017] [Indexed: 06/07/2023]
Abstract
Abnormal environment weather can cause rice photoperiod-thermo-sensitive genic male sterile (PTGMS) lines fertile or partially fertile and thus cause the mixture of true hybrids with selfing seeds. Seedling-specific green-revertible albino leaf color mutant can be used to distinguish the real hybrids. Besides, it can also be used as an ideal material to research the development of chloroplast and biosynthesis of chlorophyll. The phenotype of leaf color mutants includes light green, yellowing, albino, green-revertible albino. Gene mutations affecting the synthesis and degradation of photosynthetic pigments, lycopene and heme, the differentiation and development of chloroplast, gibberellins (GAs) biosynthesis, can change the leaf color. We have created a PTGMS line with seedling-specific green-revertible albino leaf named W01S. The leaf phenotype, pollen sterility and fertility, agronomic traits, heredity, gene mapping and RNA-Seq of the differentially expressed genes between albino and green-revertible leaves were investigated. The results showed that W01S is a practical PTGMS line as Pei'ai 64S. The mutation of candidate gene Os03g0594100 (ent-isokaurene C2-hydroxylase-like) in W01S can be related to the biosynthesis of GAs, indole acetic acids, ethylene.
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Affiliation(s)
- Xin Li
- MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, No.1, Shizishan Street, Hongshan District, Wuhan, Hubei Province, 430070, PR China
| | - Ying He
- MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, No.1, Shizishan Street, Hongshan District, Wuhan, Hubei Province, 430070, PR China.
| | - Jie Yang
- MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, No.1, Shizishan Street, Hongshan District, Wuhan, Hubei Province, 430070, PR China
| | - Yin-Hua Jia
- MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, No.1, Shizishan Street, Hongshan District, Wuhan, Hubei Province, 430070, PR China
| | - Han-Lai Zeng
- MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, No.1, Shizishan Street, Hongshan District, Wuhan, Hubei Province, 430070, PR China.
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17
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de Souza A, Wang JZ, Dehesh K. Retrograde Signals: Integrators of Interorganellar Communication and Orchestrators of Plant Development. ANNUAL REVIEW OF PLANT BIOLOGY 2017; 68:85-108. [PMID: 27813652 DOI: 10.1146/annurev-arplant-042916-041007] [Citation(s) in RCA: 127] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Interorganellar cooperation maintained via exquisitely controlled retrograde-signaling pathways is an evolutionary necessity for maintenance of cellular homeostasis. This signaling feature has therefore attracted much research attention aimed at improving understanding of the nature of these communication signals, how the signals are sensed, and ultimately the mechanism by which they integrate targeted processes that collectively culminate in organellar cooperativity. The answers to these questions will provide insight into how retrograde-signal-mediated regulatory mechanisms are recruited and which biological processes are targeted, and will advance our understanding of how organisms balance metabolic investments in growth against adaptation to environmental stress. This review summarizes the present understanding of the nature and the functional complexity of retrograde signals as integrators of interorganellar communication and orchestrators of plant development, and offers a perspective on the future of this critical and dynamic area of research.
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Affiliation(s)
- Amancio de Souza
- Institute for Integrative Genome Biology and Department of Botany and Plant Sciences, University of California, Riverside, California 92521;
| | - Jin-Zheng Wang
- Institute for Integrative Genome Biology and Department of Botany and Plant Sciences, University of California, Riverside, California 92521;
| | - Katayoon Dehesh
- Institute for Integrative Genome Biology and Department of Botany and Plant Sciences, University of California, Riverside, California 92521;
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18
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Hu X, Page MT, Sumida A, Tanaka A, Terry MJ, Tanaka R. The iron-sulfur cluster biosynthesis protein SUFB is required for chlorophyll synthesis, but not phytochrome signaling. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 89:1184-1194. [PMID: 28004871 PMCID: PMC5347852 DOI: 10.1111/tpj.13455] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 12/07/2016] [Accepted: 12/09/2016] [Indexed: 05/08/2023]
Abstract
Proteins that contain iron-sulfur (Fe-S) clusters play pivotal roles in various metabolic processes such as photosynthesis and redox metabolism. Among the proteins involved in the biosynthesis of Fe-S clusters in plants, the SUFB subunit of the SUFBCD complex appears to be unique because SUFB has been reported to be involved in chlorophyll metabolism and phytochrome-mediated signaling. To gain insights into the function of the SUFB protein, we analyzed the phenotypes of two SUFB mutants, laf6 and hmc1, and RNA interference (RNAi) lines with reduced SUFB expression. When grown in the light, the laf6 and hmc1 mutants and the SUFB RNAi lines accumulated higher levels of the chlorophyll biosynthesis intermediate Mg-protoporphyrin IX monomethylester (Mg-proto MME), consistent with the impairment of Mg-proto MME cyclase activity. Both SUFC- and SUFD-deficient RNAi lines accumulated the same intermediate, suggesting that inhibition of Fe-S cluster synthesis is the primary cause of this impairment. Dark-grown laf6 seedlings also showed an increase in protoporphyrin IX (Proto IX), Mg-proto, Mg-proto MME and 3,8-divinyl protochlorophyllide a (DV-Pchlide) levels, but this was not observed in hmc1 or the SUFB RNAi lines, nor was it complemented by SUFB overexpression. In addition, the long hypocotyl in far-red light phenotype of the laf6 mutant could not be rescued by SUFB overexpression and segregated from the pale-green SUFB-deficient phenotype, indicating it is not caused by mutation at the SUFB locus. These results demonstrate that biosynthesis of Fe-S clusters is important for chlorophyll biosynthesis, but that the laf6 phenotype is not due to a SUFB mutation.
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Affiliation(s)
- Xueyun Hu
- Institute of Low Temperature ScienceHokkaido UniversitySapporo060‐0819Japan
- School of Life Science and EngineeringSouthwest University of Science and TechnologyMianyang621010China
| | - Mike T. Page
- Biological SciencesUniversity of SouthamptonSouthamptonUK
| | - Akihiro Sumida
- Institute of Low Temperature ScienceHokkaido UniversitySapporo060‐0819Japan
| | - Ayumi Tanaka
- Institute of Low Temperature ScienceHokkaido UniversitySapporo060‐0819Japan
| | - Matthew J. Terry
- Biological SciencesUniversity of SouthamptonSouthamptonUK
- Institute for Life SciencesUniversity of SouthamptonSouthamptonUK
| | - Ryouichi Tanaka
- Institute of Low Temperature ScienceHokkaido UniversitySapporo060‐0819Japan
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19
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Garai S, Tripathy BC. Alleviation of Nitrogen and Sulfur Deficiency and Enhancement of Photosynthesis in Arabidopsis thaliana by Overexpression of Uroporphyrinogen III Methyltransferase ( UPM1). FRONTIERS IN PLANT SCIENCE 2017; 8:2265. [PMID: 29472934 PMCID: PMC5810253 DOI: 10.3389/fpls.2017.02265] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 12/27/2017] [Indexed: 05/12/2023]
Abstract
Siroheme, an iron-containing tetrapyrrole, is the prosthetic group of nitrite reductase (NiR) and sulfite reductase (SiR); it is synthesized from uroporphyrinogen III, an intermediate of chlorophyll biosynthesis, and is required for nitrogen (N) and sulfur (S) assimilation. Further, uroporphyrinogen III methyltransferase (UPM1), responsible for two methylation reactions to form dihydrosirohydrochlorin, diverts uroporphyrinogen III from the chlorophyll biosynthesis pathway toward siroheme synthesis. AtUPM1 [At5g40850] was used to produce both sense and antisense plants of Arabidopsis thaliana in order to modulate siroheme biosynthesis. In our experiments, overexpression of AtUPM1 signaled higher NiR (NII) and SiR gene and gene product expression. Increased NII expression was found to regulate and enhance the transcript and protein abundance of nitrate reductase (NR). We suggest that elevated NiR, NR, and SiR expression must have contributed to the increased synthesis of S containing amino acids in AtUPM1overexpressors, observed in our studies. We note that due to higher N and S assimilation in these plants, total protein content had increased in these plants. Consequently, chlorophyll biosynthesis increased in these sense plants. Higher chlorophyll and protein content of plants upregulated photosynthetic electron transport and carbon assimilation in the sense plants. Further, we have observed increased plant biomass in these plants, and this must have been due to increased N, S, and C assimilation. On the other hand, in the antisense plants, the transcript abundance, and protein content of NiR, and SiR was shown to decrease, resulting in reduced total protein and chlorophyll content. This led to a decrease in photosynthetic electron transport rate, carbon assimilation and plant biomass in these antisense plants. Under nitrogen or sulfur starvation conditions, the overexpressors had higher protein content and photosynthetic electron transport rate than the wild type (WT). Conversely, the antisense plants had lower protein content and photosynthetic efficiency in N-deficient environment. Our results clearly demonstrate that upregulation of siroheme biosynthesis leads to increased nitrogen and sulfur assimilation, and this imparts tolerance to nitrogen and sulfur deficiency in Arabidopsis thaliana plants.
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20
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Brzezowski P, Sharifi MN, Dent RM, Morhard MK, Niyogi KK, Grimm B. Mg chelatase in chlorophyll synthesis and retrograde signaling in Chlamydomonas reinhardtii: CHLI2 cannot substitute for CHLI1. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:3925-38. [PMID: 26809558 PMCID: PMC4915523 DOI: 10.1093/jxb/erw004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The oligomeric Mg chelatase (MgCh), consisting of the subunits CHLH, CHLI, and CHLD, is located at the central site of chlorophyll synthesis, but is also thought to have an additional function in regulatory feedback control of the tetrapyrrole biosynthesis pathway and in chloroplast retrograde signaling. In Arabidopsis thaliana and Chlamydomonas reinhardtii, two genes have been proposed to encode the CHLI subunit of MgCh. While the role of CHLI1 in A. thaliana MgCh has been substantially elucidated, different reports provide inconsistent results with regard to the function of CHLI2 in Mg chelation and retrograde signaling. In the present report, the possible functions of both isoforms were analyzed in C. reinhardtii Knockout of the CHLI1 gene resulted in complete loss of MgCh activity, absence of chlorophyll, acute light sensitivity, and, as a consequence, down-regulation of tetrapyrrole biosynthesis and photosynthesis-associated nuclear genes. These observations indicate a phenotypical resemblance of chli1 to the chlh and chld C. reinhardtii mutants previously reported. The key role of CHLI1 for MgCh reaction in comparison with the second isoform was confirmed by the rescue of chli1 with genomic CHLI1 Because CHLI2 in C. reinhardtii shows lower expression than CHLI1, strains overexpressing CHLI2 were produced in the chli1 background. However, no complementation of the chli1 phenotype was observed. Silencing of CHLI2 in the wild-type background did not result in any changes in the accumulation of tetrapyrrole intermediates or of chlorophyll. The results suggest that, unlike in A. thaliana, changes in CHLI2 content observed in the present studies do not affect formation and activity of MgCh in C. reinhardtii.
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Affiliation(s)
- Pawel Brzezowski
- Institute of Biology/Plant Physiology, Humboldt University, Philippstraße 13, D-10115 Berlin, Germany
| | - Marina N Sharifi
- Department of Plant and Microbial Biology, Howard Hughes Medical Institute, University of California, Berkeley, CA 94720-3102, USA Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Rachel M Dent
- Department of Plant and Microbial Biology, Howard Hughes Medical Institute, University of California, Berkeley, CA 94720-3102, USA Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Marius K Morhard
- Institute of Biology/Plant Physiology, Humboldt University, Philippstraße 13, D-10115 Berlin, Germany
| | - Krishna K Niyogi
- Department of Plant and Microbial Biology, Howard Hughes Medical Institute, University of California, Berkeley, CA 94720-3102, USA Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Bernhard Grimm
- Institute of Biology/Plant Physiology, Humboldt University, Philippstraße 13, D-10115 Berlin, Germany
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21
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Pattanayak GK, Tripathy BC. Modulation of biosynthesis of photosynthetic pigments and light-harvesting complex in wild-type and gun5 mutant of Arabidopsis thaliana during impaired chloroplast development. PROTOPLASMA 2016; 253:747-752. [PMID: 27001427 DOI: 10.1007/s00709-016-0958-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2015] [Accepted: 02/29/2016] [Indexed: 05/26/2023]
Abstract
Plants in response to different environmental cues need to modulate the expression of nuclear and chloroplast genomes that are in constant communication. To understand the signals that are responsible for inter-organellar communication, levulinic acid (LA), an inhibitor of 5-aminolevulinic acid dehydratase, was used to suppress the synthesis of pyrrole-derived tetrapyrroles chlorophylls. Although, it does not specifically inhibit carotenoid biosynthesis enzymes, LA reduced the carotenoid contents during photomorphogenesis of etiolated Arabidopsis seedlings. The expression of nuclear genes involved in carotenoid biosynthesis, i.e., geranylgeranyl diphosphate synthase, phytoene synthase, and phytoene desaturase, was downregulated in LA-treated seedlings. Similarly, the transcript abundance of nuclear genes, i.e., Lhcb1, PsbO, and RcbS, coding for chloroplastic proteins was severely attenuated in LA-treated samples. In contrast, LA treatment did not affect the transcript abundance of chalcone synthase, a marker gene for cytoplasm, and β-ATP synthase, a marker gene for mitochondria. This demonstrates the retrograde signaling from chloroplast to nucleus to suppress chloroplastic proteins during impaired chloroplast development. However, under identical conditions in LA-treated tetrapyrrole-deficient gun5 mutant, retrograde signal continued. The tetrapyrrole biosynthesis inhibitor LA suppressed formation of all tetrapyrroles both in WT and gun5. This rules out the role of tetrapyrroles as signaling molecules in WT and gun5. The removal of LA from the Arabidopsis seedlings restored the chlorophyll and carotenoid contents and expression of nuclear genes coding for chloroplastic proteins involved in chloroplast biogenesis. Therefore, LA could be used to modulate chloroplast biogenesis at a desired phase of chloroplast development.
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Affiliation(s)
- Gopal K Pattanayak
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Baishnab C Tripathy
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
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Chan KX, Phua SY, Crisp P, McQuinn R, Pogson BJ. Learning the Languages of the Chloroplast: Retrograde Signaling and Beyond. ANNUAL REVIEW OF PLANT BIOLOGY 2016; 67:25-53. [PMID: 26735063 DOI: 10.1146/annurev-arplant-043015-111854] [Citation(s) in RCA: 330] [Impact Index Per Article: 41.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The chloroplast can act as an environmental sensor, communicating with the cell during biogenesis and operation to change the expression of thousands of proteins. This process, termed retrograde signaling, regulates expression in response to developmental cues and stresses that affect photosynthesis and yield. Recent advances have identified many signals and pathways-including carotenoid derivatives, isoprenes, phosphoadenosines, tetrapyrroles, and heme, together with reactive oxygen species and proteins-that build a communication network to regulate gene expression, RNA turnover, and splicing. However, retrograde signaling pathways have been viewed largely as a means of bilateral communication between organelles and nuclei, ignoring their potential to interact with hormone signaling and the cell as a whole to regulate plant form and function. Here, we discuss new findings on the processes by which organelle communication is initiated, transmitted, and perceived, not only to regulate chloroplastic processes but also to intersect with cellular signaling and alter physiological responses.
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Affiliation(s)
- Kai Xun Chan
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Acton, Australian Capital Territory 2601, Australia; , , , ,
| | - Su Yin Phua
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Acton, Australian Capital Territory 2601, Australia; , , , ,
| | - Peter Crisp
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Acton, Australian Capital Territory 2601, Australia; , , , ,
| | - Ryan McQuinn
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Acton, Australian Capital Territory 2601, Australia; , , , ,
| | - Barry J Pogson
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Acton, Australian Capital Territory 2601, Australia; , , , ,
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Sun AZ, Guo FQ. Chloroplast Retrograde Regulation of Heat Stress Responses in Plants. FRONTIERS IN PLANT SCIENCE 2016; 7:398. [PMID: 27066042 PMCID: PMC4814484 DOI: 10.3389/fpls.2016.00398] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 03/14/2016] [Indexed: 05/19/2023]
Abstract
It is well known that intracellular signaling from chloroplast to nucleus plays a vital role in stress responses to survive environmental perturbations. The chloroplasts were proposed as sensors to heat stress since components of the photosynthetic apparatus housed in the chloroplast are the major targets of thermal damage in plants. Thus, communicating subcellular perturbations to the nucleus is critical during exposure to extreme environmental conditions such as heat stress. By coordinating expression of stress specific nuclear genes essential for adaptive responses to hostile environment, plants optimize different cell functions and activate acclimation responses through retrograde signaling pathways. The efficient communication between plastids and the nucleus is highly required for such diverse metabolic and biosynthetic functions during adaptation processes to environmental stresses. In recent years, several putative retrograde signals released from plastids that regulate nuclear genes have been identified and signaling pathways have been proposed. In this review, we provide an update on retrograde signals derived from tetrapyrroles, carotenoids, reactive oxygen species (ROS) and organellar gene expression (OGE) in the context of heat stress responses and address their roles in retrograde regulation of heat-responsive gene expression, systemic acquired acclimation, and cellular coordination in plants.
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Affiliation(s)
| | - Fang-Qing Guo
- The National Key Laboratory of Plant Molecular Genetics, National Center of Plant Gene Research (Shanghai) and CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology & Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of SciencesShanghai, China
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Sun AZ, Guo FQ. Chloroplast Retrograde Regulation of Heat Stress Responses in Plants. FRONTIERS IN PLANT SCIENCE 2016; 7:398. [PMID: 27066042 DOI: 10.3389/fpls.2016.00398/full] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 03/14/2016] [Indexed: 05/28/2023]
Abstract
It is well known that intracellular signaling from chloroplast to nucleus plays a vital role in stress responses to survive environmental perturbations. The chloroplasts were proposed as sensors to heat stress since components of the photosynthetic apparatus housed in the chloroplast are the major targets of thermal damage in plants. Thus, communicating subcellular perturbations to the nucleus is critical during exposure to extreme environmental conditions such as heat stress. By coordinating expression of stress specific nuclear genes essential for adaptive responses to hostile environment, plants optimize different cell functions and activate acclimation responses through retrograde signaling pathways. The efficient communication between plastids and the nucleus is highly required for such diverse metabolic and biosynthetic functions during adaptation processes to environmental stresses. In recent years, several putative retrograde signals released from plastids that regulate nuclear genes have been identified and signaling pathways have been proposed. In this review, we provide an update on retrograde signals derived from tetrapyrroles, carotenoids, reactive oxygen species (ROS) and organellar gene expression (OGE) in the context of heat stress responses and address their roles in retrograde regulation of heat-responsive gene expression, systemic acquired acclimation, and cellular coordination in plants.
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Affiliation(s)
- Ai-Zhen Sun
- The National Key Laboratory of Plant Molecular Genetics, National Center of Plant Gene Research (Shanghai) and CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology & Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences Shanghai, China
| | - Fang-Qing Guo
- The National Key Laboratory of Plant Molecular Genetics, National Center of Plant Gene Research (Shanghai) and CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology & Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences Shanghai, China
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Kleine T, Leister D. Retrograde signaling: Organelles go networking. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1313-1325. [PMID: 26997501 DOI: 10.1016/j.bbabio.2016.03.017] [Citation(s) in RCA: 132] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 03/09/2016] [Accepted: 03/14/2016] [Indexed: 10/25/2022]
Abstract
The term retrograde signaling refers to the fact that chloroplasts and mitochondria utilize specific signaling molecules to convey information on their developmental and physiological states to the nucleus and modulate the expression of nuclear genes accordingly. Signals emanating from plastids have been associated with two main networks: 'Biogenic control' is active during early stages of chloroplast development, while 'operational' control functions in response to environmental fluctuations. Early work focused on the former and its major players, the GUN proteins. However, our view of retrograde signaling has since been extended and revised. Elements of several 'operational' signaling circuits have come to light, including metabolites, signaling cascades in the cytosol and transcription factors. Here, we review recent advances in the identification and characterization of retrograde signaling components. We place particular emphasis on the strategies employed to define signaling components, spanning the entire spectrum of genetic screens, metabolite profiling and bioinformatics. This article is part of a Special Issue entitled 'EBEC 2016: 19th European Bioenergetics Conference, Riva del Garda, Italy, July 2-6, 2016', edited by Prof. Paolo Bernardi.
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Affiliation(s)
- Tatjana Kleine
- Plant Molecular Biology (Botany), Department Biology I, Ludwig-Maximilians-Universität München, 82152 Planegg-Martinsried, Germany
| | - Dario Leister
- Plant Molecular Biology (Botany), Department Biology I, Ludwig-Maximilians-Universität München, 82152 Planegg-Martinsried, Germany; Copenhagen Plant Science Centre (CPSC), Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark.
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Richter AS, Wang P, Grimm B. Arabidopsis Mg-Protoporphyrin IX Methyltransferase Activity and Redox Regulation Depend on Conserved Cysteines. PLANT & CELL PHYSIOLOGY 2016; 57:519-27. [PMID: 26759408 DOI: 10.1093/pcp/pcw007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 01/06/2016] [Indexed: 05/10/2023]
Abstract
Redox regulation is an essential post-translational regulatory mechanism in prokaryotes and eukaryotes. The reversible oxidation and reduction of cysteine residues of proteins is also important in photosynthetic organisms to control enzymatic activities, protein stability and the interaction with other proteins of chloroplast-localized proteins. Several enzymes of the plant tetrapyrrole biosynthesis pathway have been identified to be redox regulated by thioredoxins (TRXs) and NADPH-dependent thioredoxin reductase C (NTRC). Among these proteins, Mg protoporphyrin IX methyltransferase (encoded by CHLM) was identified to be activated and stabilized by interaction with NTRC. CHLM catalyzes a methyl group transfer by using S-adenosylmethionine (SAM). Here we demonstrate that three conserved cysteine residues of Arabidopsis CHLM are essential for catalytic function and redox-dependent activation of the enzyme. In vitro and in planta biochemical assays of recombinant CHLM and the Arabidopsis chlm knockout mutant overexpressing wild-type and cysteine substitution mutants of CHLM revealed modified methyltransferase activity, when the conserved cysteine residues of CHLM are replaced by serine. While C177 is responsible for redox-dependent enzyme activation, exchange of the two cysteine residues, C111 and C115, has a strong impact on enzyme activity. The modified CHLM activity of single and double mutants with cysteine substitution is presented, and the role of each cysteine residue is discussed based on a modeled structure of CHLM. These studies contribute to enhanced understanding of the physiological and enzymatic significance of redox-regulated CHLM.
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Affiliation(s)
- Andreas S Richter
- Institute of Biology/Plant Physiology, Humboldt-University Berlin, D-10115 Berlin, Germany
| | - Peng Wang
- Institute of Biology/Plant Physiology, Humboldt-University Berlin, D-10115 Berlin, Germany
| | - Bernhard Grimm
- Institute of Biology/Plant Physiology, Humboldt-University Berlin, D-10115 Berlin, Germany
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Larkin RM. Tetrapyrrole Signaling in Plants. FRONTIERS IN PLANT SCIENCE 2016; 7:1586. [PMID: 27807442 PMCID: PMC5069423 DOI: 10.3389/fpls.2016.01586] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Accepted: 10/07/2016] [Indexed: 05/03/2023]
Abstract
Tetrapyrroles make critical contributions to a number of important processes in diverse organisms. In plants, tetrapyrroles are essential for light signaling, the detoxification of reactive oxygen species, the assimilation of nitrate and sulfate, respiration, photosynthesis, and programed cell death. The misregulation of tetrapyrrole metabolism can produce toxic reactive oxygen species. Thus, it is not surprising that tetrapyrrole metabolism is strictly regulated and that tetrapyrrole metabolism affects signaling mechanisms that regulate gene expression. In plants and algae, tetrapyrroles are synthesized in plastids and were some of the first plastid signals demonstrated to regulate nuclear gene expression. In plants, the mechanism of tetrapyrrole-dependent plastid-to-nucleus signaling remains poorly understood. Additionally, some of experiments that tested ideas for possible signaling mechanisms appeared to produce conflicting data. In some instances, these conflicts are potentially explained by different experimental conditions. Although the biological function of tetrapyrrole signaling is poorly understood, there is compelling evidence that this signaling is significant. Specifically, this signaling appears to affect the accumulation of starch and may promote abiotic stress tolerance. Tetrapyrrole-dependent plastid-to-nucleus signaling interacts with a distinct plastid-to-nucleus signaling mechanism that depends on GENOMES UNCUOPLED1 (GUN1). GUN1 contributes to a variety of processes, such as chloroplast biogenesis, the circadian rhythm, abiotic stress tolerance, and development. Thus, the contribution of tetrapyrrole signaling to plant function is potentially broader than we currently appreciate. In this review, I discuss these aspects of tetrapyrrole signaling.
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Kobayashi K, Masuda T. Transcriptional Regulation of Tetrapyrrole Biosynthesis in Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2016; 7:1811. [PMID: 27990150 PMCID: PMC5130987 DOI: 10.3389/fpls.2016.01811] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 11/16/2016] [Indexed: 05/17/2023]
Abstract
Biosynthesis of chlorophyll (Chl) involves many enzymatic reactions that share several first steps for biosynthesis of other tetrapyrroles such as heme, siroheme, and phycobilins. Chl allows photosynthetic organisms to capture light energy for photosynthesis but with simultaneous threat of photooxidative damage to cells. To prevent photodamage by Chl and its highly photoreactive intermediates, photosynthetic organisms have developed multiple levels of regulatory mechanisms to coordinate tetrapyrrole biosynthesis (TPB) with the formation of photosynthetic and photoprotective systems and to fine-tune the metabolic flow with the varying needs of Chl and other tetrapyrroles under various developmental and environmental conditions. Among a wide range of regulatory mechanisms of TPB, this review summarizes transcriptional regulation of TPB genes during plant development, with focusing on several transcription factors characterized in Arabidopsis thaliana. Key TPB genes are tightly coexpressed with other photosynthesis-associated nuclear genes and are induced by light, oscillate in a diurnal and circadian manner, are coordinated with developmental and nutritional status, and are strongly downregulated in response to arrested chloroplast biogenesis. LONG HYPOCOTYL 5 and PHYTOCHROME-INTERACTING FACTORs, which are positive and negative transcription factors with a wide range of light signaling, respectively, target many TPB genes for light and circadian regulation. GOLDEN2-LIKE transcription factors directly regulate key TPB genes to fine-tune the formation of the photosynthetic apparatus with chloroplast functionality. Some transcription factors such as FAR-RED ELONGATED HYPOCOTYL3, REVEILLE1, and scarecrow-like transcription factors may directly regulate some specific TPB genes, whereas other factors such as GATA transcription factors are likely to regulate TPB genes in an indirect manner. Comprehensive transcriptional analyses of TPB genes and detailed characterization of key transcriptional regulators help us obtain a whole picture of transcriptional control of TPB in response to environmental and endogenous cues.
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Ibata H, Nagatani A, Mochizuki N. CHLH/GUN5 Function in Tetrapyrrole Metabolism Is Correlated with Plastid Signaling but not ABA Responses in Guard Cells. FRONTIERS IN PLANT SCIENCE 2016; 7:1650. [PMID: 27872634 PMCID: PMC5098175 DOI: 10.3389/fpls.2016.01650] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 10/20/2016] [Indexed: 05/20/2023]
Abstract
Expression of Photosynthesis-Associated Nuclear Genes (PhANGs) is controlled by environmental stimuli and plastid-derived signals ("plastid signals") transmitting the developmental and functional status of plastids to the nucleus. Arabidopsis genomes uncoupled (gun) mutants exhibit defects in plastid signaling, leading to ectopic expression of PhANGs in the absence of chloroplast development. GUN5 encodes the plastid-localized Mg-chelatase enzyme subunit (CHLH), and recent studies suggest that CHLH is a multifunctional protein involved in tetrapyrrole biosynthesis, plastid signaling and ABA responses in guard cells. To understand the basis of CHLH multifunctionality, we investigated 15 gun5 missense mutant alleles and transgenic lines expressing a series of truncated CHLH proteins in a severe gun5 allele (cch) background (tCHLHs, 10 different versions). Here, we show that Mg-chelatase function and plastid signaling are generally correlated; in contrast, based on the analysis of the gun5 missense mutant alleles, ABA-regulated stomatal control is distinct from these two other functions. We found that none of the tCHLHs could restore plastid-signaling or Mg-chelatase functions. Additionally, we found that both the C-terminal half and N-terminal half of CHLH function in ABA-induced stomatal movement.
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Czarnecki O, Bryan AC, Jawdy SS, Yang X, Cheng ZM, Chen JG, Tuskan GA. Simultaneous knockdown of six non-family genes using a single synthetic RNAi fragment in Arabidopsis thaliana. PLANT METHODS 2016; 12:16. [PMID: 26889205 PMCID: PMC4756541 DOI: 10.1186/s13007-016-0116-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 02/08/2016] [Indexed: 05/19/2023]
Abstract
BACKGROUND Genetic engineering of plants that results in successful establishment of new biochemical or regulatory pathways requires stable introduction of one or more genes into the plant genome. It might also be necessary to down-regulate or turn off expression of endogenous genes in order to reduce activity of competing pathways. An established way to knockdown gene expression in plants is expressing a hairpin-RNAi construct, eventually leading to degradation of a specifically targeted mRNA. Knockdown of multiple genes that do not share homologous sequences is still challenging and involves either sophisticated cloning strategies to create vectors with different serial expression constructs or multiple transformation events that is often restricted by a lack of available transformation markers. RESULTS Synthetic RNAi fragments were assembled in yeast carrying homologous sequences to six or seven non-family genes and introduced into pAGRIKOLA. Transformation of Arabidopsis thaliana and subsequent expression analysis of targeted genes proved efficient knockdown of all target genes. CONCLUSIONS We present a simple and cost-effective method to create constructs to simultaneously knockdown multiple non-family genes or genes that do not share sequence homology. The presented method can be applied in plant and animal synthetic biology as well as traditional plant and animal genetic engineering.
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Affiliation(s)
- Olaf Czarnecki
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA ; KWS SAAT SE, Grimsehlstraße 31, 37555 Einbeck, Germany
| | - Anthony C Bryan
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Sara S Jawdy
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Xiaohan Yang
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Zong-Ming Cheng
- Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996 USA
| | - Jin-Gui Chen
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Gerald A Tuskan
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
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Wang P, Grimm B. Organization of chlorophyll biosynthesis and insertion of chlorophyll into the chlorophyll-binding proteins in chloroplasts. PHOTOSYNTHESIS RESEARCH 2015; 126:189-202. [PMID: 25957270 DOI: 10.1007/s11120-015-0154-5] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 04/30/2015] [Indexed: 05/23/2023]
Abstract
Oxygenic photosynthesis requires chlorophyll (Chl) for the absorption of light energy, and charge separation in the reaction center of photosystem I and II, to feed electrons into the photosynthetic electron transfer chain. Chl is bound to different Chl-binding proteins assembled in the core complexes of the two photosystems and their peripheral light-harvesting antenna complexes. The structure of the photosynthetic protein complexes has been elucidated, but mechanisms of their biogenesis are in most instances unknown. These processes involve not only the assembly of interacting proteins, but also the functional integration of pigments and other cofactors. As a precondition for the association of Chl with the Chl-binding proteins in both photosystems, the synthesis of the apoproteins is synchronized with Chl biosynthesis. This review aims to summarize the present knowledge on the posttranslational organization of Chl biosynthesis and current attempts to envision the proceedings of the successive synthesis and integration of Chl into Chl-binding proteins in the thylakoid membrane. Potential auxiliary factors, contributing to the control and organization of Chl biosynthesis and the association of Chl with the Chl-binding proteins during their integration into photosynthetic complexes, are discussed in this review.
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Affiliation(s)
- Peng Wang
- Institute of Biology/Plant Physiology, Humboldt-University Berlin, Philippstraße 13, 10115, Berlin, Germany
| | - Bernhard Grimm
- Institute of Biology/Plant Physiology, Humboldt-University Berlin, Philippstraße 13, 10115, Berlin, Germany.
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Regulation and function of tetrapyrrole biosynthesis in plants and algae. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:968-85. [PMID: 25979235 DOI: 10.1016/j.bbabio.2015.05.007] [Citation(s) in RCA: 127] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 04/21/2015] [Accepted: 05/07/2015] [Indexed: 12/20/2022]
Abstract
Tetrapyrroles are macrocyclic molecules with various structural variants and multiple functions in Prokaryotes and Eukaryotes. Present knowledge about the metabolism of tetrapyrroles reflects the complex evolution of the pathway in different kingdoms of organisms, the complexity of structural and enzymatic variations of enzymatic steps, as well as a wide range of regulatory mechanisms, which ensure adequate synthesis of tetrapyrrole end-products at any time of development and environmental condition. This review intends to highlight new findings of research on tetrapyrrole biosynthesis in plants and algae. In the course of the heme and chlorophyll synthesis in these photosynthetic organisms, glutamate, one of the central and abundant metabolites, is converted into highly photoreactive tetrapyrrole intermediates. Thereby, several mechanisms of posttranslational control are thought to be essential for a tight regulation of each enzymatic step. Finally, we wish to discuss the potential role of tetrapyrroles in retrograde signaling and point out perspectives of the formation of macromolecular protein complexes in tetrapyrrole biosynthesis as an efficient mechanism to ensure a fine-tuned metabolic flow in the pathway. This article is part of a Special Issue entitled: Chloroplast Biogenesis.
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Dietz KJ. Efficient high light acclimation involves rapid processes at multiple mechanistic levels. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:2401-14. [PMID: 25573858 DOI: 10.1093/jxb/eru505] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Like no other chemical or physical parameter, the natural light environment of plants changes with high speed and jumps of enormous intensity. To cope with this variability, photosynthetic organisms have evolved sensing and response mechanisms that allow efficient acclimation. Most signals originate from the chloroplast itself. In addition to very fast photochemical regulation, intensive molecular communication is realized within the photosynthesizing cell, optimizing the acclimation process. Current research has opened up new perspectives on plausible but mostly unexpected complexity in signalling events, crosstalk, and process adjustments. Within seconds and minutes, redox states, levels of reactive oxygen species, metabolites, and hormones change and transmit information to the cytosol, modifying metabolic activity, gene expression, translation activity, and alternative splicing events. Signalling pathways on an intermediate time scale of several minutes to a few hours pave the way for long-term acclimation. Thereby, a new steady state of the transcriptome, proteome, and metabolism is realized within rather short time periods irrespective of the previous acclimation history to shade or sun conditions. This review provides a time line of events during six hours in the 'stressful' life of a plant.
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Affiliation(s)
- Karl-Josef Dietz
- Biochemistry and Physiology of Plants, Faculty of Biology, W5-134, Bielefeld University, University Street 25, 33501 Bielefeld, Germany
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Busch AW, Montgomery BL. Interdependence of tetrapyrrole metabolism, the generation of oxidative stress and the mitigative oxidative stress response. Redox Biol 2015; 4:260-71. [PMID: 25618582 PMCID: PMC4315935 DOI: 10.1016/j.redox.2015.01.010] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 01/12/2015] [Accepted: 01/14/2015] [Indexed: 01/01/2023] Open
Abstract
Tetrapyrroles are involved in light harvesting and light perception, electron-transfer reactions, and as co-factors for key enzymes and sensory proteins. Under conditions in which cells exhibit stress-induced imbalances of photosynthetic reactions, or light absorption exceeds the ability of the cell to use photoexcitation energy in synthesis reactions, redox imbalance can occur in photosynthetic cells. Such conditions can lead to the generation of reactive oxygen species (ROS) associated with alterations in tetrapyrrole homeostasis. ROS accumulation can result in cellular damage and detrimental effects on organismal fitness, or ROS molecules can serve as signals to induce a protective or damage-mitigating oxidative stress signaling response in cells. Induced oxidative stress responses include tetrapyrrole-dependent and -independent mechanisms for mitigating ROS generation and/or accumulation. Thus, tetrapyrroles can be contributors to oxidative stress, but are also essential in the oxidative stress response to protect cells by contributing to detoxification of ROS. In this review, we highlight the interconnection and interdependence of tetrapyrrole metabolism with the occurrence of oxidative stress and protective oxidative stress signaling responses in photosynthetic organisms. Tetrapyrroles are involved in light sensing and oxidative stress mitigation. Reactive oxygen species (ROS) can form upon light exposure of free tetrapyrroles. Tetrapyrrole homeostasis must be tightly regulated to avoid oxidative stress. ROS can result in cellular damage or oxidative stress signaling in cells.
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Bobik K, Burch-Smith TM. Chloroplast signaling within, between and beyond cells. FRONTIERS IN PLANT SCIENCE 2015; 6:781. [PMID: 26500659 PMCID: PMC4593955 DOI: 10.3389/fpls.2015.00781] [Citation(s) in RCA: 129] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 09/10/2015] [Indexed: 05/18/2023]
Abstract
The most conspicuous function of plastids is the oxygenic photosynthesis of chloroplasts, yet plastids are super-factories that produce a plethora of compounds that are indispensable for proper plant physiology and development. Given their origins as free-living prokaryotes, it is not surprising that plastids possess their own genomes whose expression is essential to plastid function. This semi-autonomous character of plastids requires the existence of sophisticated regulatory mechanisms that provide reliable communication between them and other cellular compartments. Such intracellular signaling is necessary for coordinating whole-cell responses to constantly varying environmental cues and cellular metabolic needs. This is achieved by plastids acting as receivers and transmitters of specific signals that coordinate expression of the nuclear and plastid genomes according to particular needs. In this review we will consider the so-called retrograde signaling occurring between plastids and nuclei, and between plastids and other organelles. Another important role of the plastid we will discuss is the involvement of plastid signaling in biotic and abiotic stress that, in addition to influencing retrograde signaling, has direct effects on several cellular compartments including the cell wall. We will also review recent evidence pointing to an intriguing function of chloroplasts in regulating intercellular symplasmic transport. Finally, we consider an intriguing yet less widely known aspect of plant biology, chloroplast signaling from the perspective of the entire plant. Thus, accumulating evidence highlights that chloroplasts, with their complex signaling pathways, provide a mechanism for exquisite regulation of plant development, metabolism and responses to the environment. As chloroplast processes are targeted for engineering for improved productivity the effect of such modifications on chloroplast signaling will have to be carefully considered in order to avoid unintended consequences on plant growth and development.
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Affiliation(s)
| | - Tessa M. Burch-Smith
- *Correspondence: Tessa M. Burch-Smith, Department of Biochemistry, Cellular and Molecular Biology, University of Tennessee, 1414 Cumberland Avenue, M407 Walters Life Science, Knoxville, TN 37932, USA,
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Function of Tetrapyrroles, Regulation of Tetrapyrrole Metabolism and Methods for Analyses of Tetrapyrroles. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.proche.2015.03.025] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Organization, function and substrates of the essential Clp protease system in plastids. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1847:915-30. [PMID: 25482260 DOI: 10.1016/j.bbabio.2014.11.012] [Citation(s) in RCA: 128] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 11/20/2014] [Indexed: 01/21/2023]
Abstract
Intra-plastid proteolysis is essential in plastid biogenesis, differentiation and plastid protein homeostasis (proteostasis). We provide a comprehensive review of the Clp protease system present in all plastid types and we draw lessons from structural and functional information of bacterial Clp systems. The Clp system plays a central role in plastid development and function, through selective removal of miss-folded, aggregated, or otherwise unwanted proteins. The Clp system consists of a tetradecameric proteolytic core with catalytically active ClpP and inactive ClpR subunits, hexameric ATP-dependent chaperones (ClpC,D) and adaptor protein(s) (ClpS1) enhancing delivery of subsets of substrates. Many structural and functional features of the plastid Clp system are now understood though extensive reverse genetics analysis combined with biochemical analysis, as well as large scale quantitative proteomics for loss-of-function mutants of Clp core, chaperone and ClpS1 subunits. Evolutionary diversification of Clp system across non-photosynthetic and photosynthetic prokaryotes and organelles is illustrated. Multiple substrates have been suggested based on their direct interaction with the ClpS1 adaptor or screening of different loss-of-function protease mutants. The main challenge is now to determine degradation signals (degrons) in Clp substrates and substrate delivery mechanisms, as well as functional interactions of Clp with other plastid proteases. This article is part of a Special Issue entitled: Chloroplast Biogenesis.
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Phung TH, Jung S. Perturbed porphyrin biosynthesis contributes to differential herbicidal symptoms in photodynamically stressed rice (Oryza sativa) treated with 5-aminolevulinic acid and oxyfluorfen. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2014; 116:103-10. [PMID: 25454526 DOI: 10.1016/j.pestbp.2014.10.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 10/03/2014] [Accepted: 10/03/2014] [Indexed: 05/22/2023]
Abstract
This paper focuses on the molecular mechanism of deregulated porphyrin biosynthesis in rice plants under photodynamic stress imposed by an exogenous supply of 5-aminolevulinic acid (ALA) and oxyfluorfen (OF). Plants treated with 5 mM ALA or 50 µM OF exhibited differential herbicidal symptoms as characterized by white and brown necrosis, respectively, with substantial increases in cellular leakage and malondialdehyde production. Protoporphyrin IX accumulated to higher levels after 1 day of ALA and OF treatment, whereas it decreased to the control level after 2 days of ALA treatment. Plants responded to OF by greatly decreasing the levels of Mg-protoporphyrin IX (MgProto IX), MgProto IX methyl ester, and protochlorophyllide to levels lower than control, whereas their levels drastically increased 1 day after ALA treatment and then disappeared 2 days after the treatment. Enzyme activity and transcript levels of HEMA1, GSA and ALAD for ALA synthesis greatly decreased in ALA- and OF-treated plants. Transcript levels of PPO1, CHLH, CHLI, and PORB genes involving Mg-porphyrin synthesis continuously decreased in ALA- and OF-treated plants, with greater decreases in ALA-treated plants. By contrast, up-regulation of FC2 and HO2 genes in Fe-porphyrin branch was noticeable in ALA and OF-treated plants 1 day and 2 days after the treatments, respectively. Decreased transcript levels of nuclear-encoded genes Lhcb1, Lhcb6, and RbcS were accompanied by disappearance of MgProto IX in ALA- and OF-treated plants after 2 days of the treatments. Under photodynamic stress imposed by ALA and OF, tight control of porphyrin biosynthesis prevents accumulation of toxic metabolic intermediates not only by down-regulation of their biosynthesis but also by photodynamic degradation. The up-regulation of FC2 and HO2 also appears to compensate for the photodynamic stress-induced damage.
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Affiliation(s)
- Thu-Ha Phung
- School of Life Sciences and Biotechnology, BK21 Plus KNU Creative Bioresearch Group, Kyungpook National University, Daegu 702-701, Republic of Korea
| | - Sunyo Jung
- School of Life Sciences and Biotechnology, BK21 Plus KNU Creative Bioresearch Group, Kyungpook National University, Daegu 702-701, Republic of Korea.
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Chen X, Wang X, Feng J, Chen Y, Fang Y, Zhao S, Zhao A, Zhang M, Liu L. Structural insights into the catalytic mechanism of Synechocystis magnesium protoporphyrin IX O-methyltransferase (ChlM). J Biol Chem 2014; 289:25690-8. [PMID: 25077963 DOI: 10.1074/jbc.m114.584920] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Magnesium protoporphyrin IX O-methyltransferase (ChlM) catalyzes transfer of the methyl group from S-adenosylmethionine to the carboxyl group of the C13 propionate side chain of magnesium protoporphyrin IX. This reaction is the second committed step in chlorophyll biosynthesis from protoporphyrin IX. Here we report the crystal structures of ChlM from the cyanobacterium Synechocystis sp. PCC 6803 in complex with S-adenosylmethionine and S-adenosylhomocysteine at resolutions of 1.6 and 1.7 Å, respectively. The structures illustrate the molecular basis for cofactor and substrate binding and suggest that conformational changes of the two "arm" regions may modulate binding and release of substrates/products to and from the active site. Tyr-28 and His-139 were identified to play essential roles for methyl transfer reaction but are not indispensable for cofactor/substrate binding. Based on these structural and functional findings, a catalytic model is proposed.
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Affiliation(s)
- Xuemin Chen
- From the Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China, the University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiao Wang
- From the Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China, the University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Juan Feng
- From the Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China, the University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yuhong Chen
- From the Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Ying Fang
- From the Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China, the University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Shun Zhao
- From the Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China, the University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Aiguo Zhao
- From the Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China, the University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Min Zhang
- the Engineering Research Center for Biomedical Materials, School of Life Sciences, Anhui University, Hefei, Anhui, 230601, China, and
| | - Lin Liu
- From the Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China,
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