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Lv Z, Lan G, Bai B, Yu P, Wang C, Zhang H, Zhong C, Zhao X, Yu H. Identification of candidate genes associated with peanut pod length by combined analysis of QTL-seq and RNA-seq. Genomics 2024; 116:110835. [PMID: 38521201 DOI: 10.1016/j.ygeno.2024.110835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 03/14/2024] [Accepted: 03/21/2024] [Indexed: 03/25/2024]
Abstract
Pod length (PL) is one of the major traits determining pod size and yield of peanut. Discovering the quantitative trait loci (QTL) and identifying candidate genes associated with PL are essential for breeding high-yield peanut. In this study, quantitative trait loci sequencing (QTL-seq) was performed using the F2 population constructed by a short-pod variety Tifrunner (Tif) and a long-pod line Lps, and a 0.77 Mb genomic region on chromosome 07 was identified as the candidate region for PL. Then, the candidate region was narrowed to a 265.93 kb region by traditional QTL approach. RNA-seq analysis showed that there were four differentially expressed genes (DEGs) in the candidate region, among which Arahy.PF2L6F (AhCDC48) and Arahy.P4LK2T (AhTAA1) were speculated to be PL-related candidate genes. These results were informative for the elucidation of the underlying regulatory mechanism in peanut pod length and would facilitate further identification of valuable target genes.
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Affiliation(s)
- Zhenghao Lv
- Peanut Research Institute, College of Agronomy, Shenyang Agricultural University, Shenyang 110866, China
| | - Guohu Lan
- Peanut Research Institute, College of Agronomy, Shenyang Agricultural University, Shenyang 110866, China
| | - Baiyi Bai
- College of Agriculture and Horticulture, Liaoning Agriculture Ovcational and Technical College, Yingkou 115009, China
| | - Penghao Yu
- Peanut Research Institute, College of Agronomy, Shenyang Agricultural University, Shenyang 110866, China
| | - Chuantang Wang
- Peanut Research Institute, College of Agronomy, Shenyang Agricultural University, Shenyang 110866, China; Shandong Peanut Research Institute, Qingdao 266100, China
| | - He Zhang
- Peanut Research Institute, College of Agronomy, Shenyang Agricultural University, Shenyang 110866, China
| | - Chao Zhong
- Peanut Research Institute, College of Agronomy, Shenyang Agricultural University, Shenyang 110866, China
| | - Xinhua Zhao
- Peanut Research Institute, College of Agronomy, Shenyang Agricultural University, Shenyang 110866, China
| | - Haiqiu Yu
- Peanut Research Institute, College of Agronomy, Shenyang Agricultural University, Shenyang 110866, China; College of Agriculture and Horticulture, Liaoning Agriculture Ovcational and Technical College, Yingkou 115009, China.
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Lyu HN, Fu C, Chai X, Gong Z, Zhang J, Wang J, Wang J, Dai L, Xu C. Systematic thermal analysis of the Arabidopsis proteome: Thermal tolerance, organization, and evolution. Cell Syst 2023; 14:883-894.e4. [PMID: 37734376 DOI: 10.1016/j.cels.2023.08.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 05/29/2023] [Accepted: 08/25/2023] [Indexed: 09/23/2023]
Abstract
Understanding the thermal stability of the plant proteome in the context of the native cellular environment would aid the design of crops with high thermal tolerance, but only limited such data are available. Here, we applied quantitative mass spectrometry to profile the thermal stability of the Arabidopsis proteome and identify thermo-sensitive and thermo-resilient protein networks in Arabidopsis, providing a basis for understanding heat-induced damage. We also show that the similarities of the protein-melting curves can be used as a proxy to evaluate system-wide protein-protein interactions in non-engineered plants and enable the identification of transient interactions exhibited by metabolons in the context of the cellular environment. Finally, we report a systematic comparison of the thermal stability of paralogs in Arabidopsis to aid the investigation and understanding of gene duplication and protein evolution. Taken together, our results could have broad implications for the fields of plant thermal tolerance, plant protein assemblies, and evolution.
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Affiliation(s)
- Hai-Ning Lyu
- State Key Laboratory for Quality Ensurance and Sustainable Use of Dao-di Herbs, Artemisinin Research Center, and Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Chunjin Fu
- Department of Nephrology, Shenzhen Key Laboratory of Kidney Diseases, Shenzhen Clinical Research Centre for Geriatrics, Shenzhen People's Hospital, The First Affiliated Hospital, Southern University of Science and Technology, Shenzhen 518020, China
| | - Xin Chai
- State Key Laboratory for Quality Ensurance and Sustainable Use of Dao-di Herbs, Artemisinin Research Center, and Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Zipeng Gong
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Provincial Key Laboratory of Pharmaceutics, Guizhou Medical University, Guiyang 550004, China
| | - Junzhe Zhang
- State Key Laboratory for Quality Ensurance and Sustainable Use of Dao-di Herbs, Artemisinin Research Center, and Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Jiaqi Wang
- School of Pharmaceutical Sciences (Shenzhen), Sun Yat-sen University, Shenzhen 518107, China
| | - Jigang Wang
- State Key Laboratory for Quality Ensurance and Sustainable Use of Dao-di Herbs, Artemisinin Research Center, and Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China; Department of Nephrology, Shenzhen Key Laboratory of Kidney Diseases, Shenzhen Clinical Research Centre for Geriatrics, Shenzhen People's Hospital, The First Affiliated Hospital, Southern University of Science and Technology, Shenzhen 518020, China; School of Traditional Chinese Medicine and School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China.
| | - Lingyun Dai
- Department of Nephrology, Shenzhen Key Laboratory of Kidney Diseases, Shenzhen Clinical Research Centre for Geriatrics, Shenzhen People's Hospital, The First Affiliated Hospital, Southern University of Science and Technology, Shenzhen 518020, China.
| | - Chengchao Xu
- State Key Laboratory for Quality Ensurance and Sustainable Use of Dao-di Herbs, Artemisinin Research Center, and Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China; Department of Nephrology, Shenzhen Key Laboratory of Kidney Diseases, Shenzhen Clinical Research Centre for Geriatrics, Shenzhen People's Hospital, The First Affiliated Hospital, Southern University of Science and Technology, Shenzhen 518020, China.
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3
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Lin X, Huang L, Liang H, Hou C, Ling X, Chen Y, Yang P, Wu Q, Zhao H, Wu S, Zhan R, Ma D, Yang J. Genome-wide identification and functional characterization of borneol dehydrogenases in Wurfbainia villosa. PLANTA 2023; 258:69. [PMID: 37608037 DOI: 10.1007/s00425-023-04221-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 08/01/2023] [Indexed: 08/24/2023]
Abstract
MAIN CONCLUSION Genome-wide screening of short-chain dehydrogenases/reductases (SDR) family reveals functional diversification of borneol dehydrogenase (BDH) in Wurfbainia villosa. Wurfbainia villosa is an important medicinal plant, the fruits of which accumulate abundant terpenoids, especially bornane-type including borneol and camphor. The borneol dehydrogenase (BDH) responsible for the conversion of borneol to camphor in W. villosa remains unknown. BDH is one member of short-chain dehydrogenases/reductases (SDR) family. Here, a total of 115 classical WvSDR genes were identified through genome-wide screening. These WvSDRs were unevenly distributed on different chromosomes. Seven candidate WvBDHs based on phylogenetic analysis and expression levels were selected for cloning. Of them, four BDHs can catalyze different configurations of borneol and other monoterpene alcohol substrates to generate the corresponding oxidized products. WvBDH1 and WvBDH2, preferred (+)-borneol to (-)-borneol, producing the predominant ( +)-camphor. WvBDH3 yielded approximate equivalent amount of (+)-camphor and (-)-camphor, in contrast, WvBDH4 generated exclusively (+)-camphor. The metabolic profiles of the seeds showed that the borneol and camphor present were in the dextrorotatory configuration. Enzyme kinetics and expression pattern in different tissues suggested WvBDH2 might be involved in the biosynthesis of camphor in W. villosa. All results will increase the understanding of functional diversity of BDHs.
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Affiliation(s)
- Xiaojing Lin
- School of Pharmaceutical Science, Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China
- Key Laboratory of Chinese Medicinal Resource from Lingnan (Ministry of Education), Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China
| | - Linxuan Huang
- School of Pharmaceutical Science, Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China
- Key Laboratory of Chinese Medicinal Resource from Lingnan (Ministry of Education), Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China
| | - Huilin Liang
- School of Pharmaceutical Science, Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China
- Key Laboratory of Chinese Medicinal Resource from Lingnan (Ministry of Education), Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China
| | - Chen Hou
- Guangdong Provincial Key Laboratory of Silviculture, Protection and Utilization, Guangdong Academy of Forestry, Guangzhou, 510006, People's Republic of China
- Guangdong Academy of Forestry, Guangzhou, 510006, People's Republic of China
| | - Xuli Ling
- School of Pharmaceutical Science, Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China
- Key Laboratory of Chinese Medicinal Resource from Lingnan (Ministry of Education), Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China
| | - Yuanxia Chen
- School of Pharmaceutical Science, Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China
- Key Laboratory of Chinese Medicinal Resource from Lingnan (Ministry of Education), Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China
| | - Peng Yang
- School of Pharmaceutical Science, Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China
- Key Laboratory of Chinese Medicinal Resource from Lingnan (Ministry of Education), Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China
| | - Qingwen Wu
- School of Pharmaceutical Science, Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China
- Key Laboratory of Chinese Medicinal Resource from Lingnan (Ministry of Education), Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China
| | - Haiying Zhao
- Key Laboratory of Chinese Medicinal Resource from Lingnan (Ministry of Education), Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China
| | - Sirong Wu
- School of Pharmaceutical Science, Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China
| | - Ruoting Zhan
- School of Pharmaceutical Science, Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China
- Key Laboratory of Chinese Medicinal Resource from Lingnan (Ministry of Education), Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China
| | - Dongming Ma
- School of Pharmaceutical Science, Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China.
- Key Laboratory of Chinese Medicinal Resource from Lingnan (Ministry of Education), Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China.
| | - Jinfen Yang
- School of Pharmaceutical Science, Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China.
- Key Laboratory of Chinese Medicinal Resource from Lingnan (Ministry of Education), Guangzhou University of Chinese Medicine, Guangzhou, 510006, People's Republic of China.
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Rodríguez AA, Vilas JM, Sartore GD, Bezus R, Colazo J, Maiale SJ. Field and genetic evidence support the photosynthetic performance index (PI ABS) as an indicator of rice grain yield. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2023; 201:107897. [PMID: 37487369 DOI: 10.1016/j.plaphy.2023.107897] [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: 02/08/2023] [Revised: 07/12/2023] [Accepted: 07/14/2023] [Indexed: 07/26/2023]
Abstract
The rice breeding process for grain yield could be effectively enhanced by developing efficient tools that accelerate plant selection through the rapid determination of reliable predictors. In this study, we have described various associations between grain yield and photosynthetic parameters, which can be easily and quickly obtained using a non-invasive technique on the flag leaf during the anthesis stage. Among the analyzed photosynthetic parameters, the photosynthetic performance index (PIABS) stood out due to its strong association with grain yield. A genome-wide association analysis conducted on plants from a rice diversity panel at the tillering stage revealed the presence of a quantitative trait locus on chromosome 9. This locus was characterized by a group of candidate chloroplastic genes that exhibited contrasting haplotypes for PIABS. An analysis of these haplotypes revealed a clear division into two groups. One group consisted of haplotypes linked to high values of PIABS, which were predominantly associated with Japonica spp. subpopulations. The other group consisted of haplotypes linked to low values of PIABS, which were exclusively associated with Indica spp. subpopulations. Japonica spp. genotypes exhibited higher values in the yield component panicle weight compared with the Indica spp. genotypes. The findings of this study indicate that PIABS could serve as an early predictor of yield parameters during the tillering stage in rice breeding processes.
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Affiliation(s)
- Andrés Alberto Rodríguez
- Laboratorio de Fisiología y Asistencia al Mejoramiento Vegetal, Instituto Tecnológico de Chascomús (CONICET-UNSAM), Escuela de Bio y Nanotecnologías (UNSAM), Argentina.
| | - Juan Manuel Vilas
- Laboratorio de Fisiología y Asistencia al Mejoramiento Vegetal, Instituto Tecnológico de Chascomús (CONICET-UNSAM), Escuela de Bio y Nanotecnologías (UNSAM), Argentina.
| | - Gustavo Daniel Sartore
- Facultad de Ciencias Agrarias y Forestales, Universidad Nacional de la Plata, 60 y 119, La Plata, Pcia. Bs. As., Argentina.
| | - Rodolfo Bezus
- Facultad de Ciencias Agrarias y Forestales, Universidad Nacional de la Plata, 60 y 119, La Plata, Pcia. Bs. As., Argentina.
| | - José Colazo
- EEA INTA Concepción del Uruguay, Ruta 39 Km 143, Concepción del Uruguay, Pcia. de Entre Ríos, Argentina.
| | - Santiago Javier Maiale
- Laboratorio de Fisiología y Asistencia al Mejoramiento Vegetal, Instituto Tecnológico de Chascomús (CONICET-UNSAM), Escuela de Bio y Nanotecnologías (UNSAM), Argentina.
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Ma Q, Niu C, Wang C, Chen C, Li Y, Wei M. Effects of differentially expressed microRNAs induced by rootstocks and silicon on improving chilling tolerance of cucumber seedlings (Cucumis sativus L.). BMC Genomics 2023; 24:250. [PMID: 37165319 PMCID: PMC10173649 DOI: 10.1186/s12864-023-09337-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 04/26/2023] [Indexed: 05/12/2023] Open
Abstract
BACKGROUND Rootstocks can improve the chilling tolerance of grafted cucumbers, but their effectiveness varies. Rootstocks with strong de-blooming capacity may result in lower chilling tolerance of grafted cucumbers compared to those with weak de-blooming capacity, while also reducing the silicon absorption. However, it remains unclear whether this reduction in chilling tolerance is due to differences in rootstock genotypes or the reduction in silicon absorption. RESULTS The chilling tolerance of cucumber seedlings was improved by using rootstocks and silicon nutrition. Rootstocks had a more significant effect than silicon nutrition, and the weak de-blooming rootstock 'Yunnan figleaf gourd' was superior to the strong de-blooming rootstock 'Huangchenggen No. 2'. Compared to self-rooted cucumber, twelve miRNAs were regulated by two rootstocks, including seven identical miRNAs (novel-mir23, novel-mir26, novel-mir30, novel-mir37, novel-mir46, miR395a and miR398a-3p) and five different miRNAs (novel-mir32, novel-mir38, novel-mir65, novel-mir78 and miR397a). Notably, four of these miRNAs (novel-mir38, novel-mir65, novel-mir78 and miR397a) were only identified in 'Yunnan figleaf gourd'-grafted cucumbers. Furthermore, six miRNAs (miR168a-5p, miR390a-5p, novel-mir26, novel-mir55, novel-mir67 and novel-mir70) were found to be responsive to exogenous silicon. Target gene prediction for 20 miRNAs resulted in 520 genes. Functional analysis of these target genes showed that 'Yunnan figleaf gourd' improves the chilling tolerance of cucumber by regulating laccase synthesis and sulfate metabolism, while 'Huangchenggen No. 2' and exogenous silicon reduced chilling stress damage to cucumber by regulating ROS scavenging and protein protection, respectively. CONCLUSION Among the identified miRNAs, novel-mir46 and miR398a-3p were found in cucumbers in response to chilling stress and two types of rootstocks. However, no identical miRNAs were identified in response to chilling stress and silicon. In addition, the differential expression of novel-mir38, novel-mir65, novel-mir78 and miR397a may be one of the important reasons for the differences in chilling tolerance of grafted cucumbers caused by two types of rootstocks.
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Affiliation(s)
- Qiang Ma
- College of Horticultural Science and Engineering, Shandong Agricultural University, Taian, 271018, China
| | - Chenxu Niu
- College of Horticultural Science and Engineering, Shandong Agricultural University, Taian, 271018, China
| | - Chao Wang
- College of Horticultural Science and Engineering, Shandong Agricultural University, Taian, 271018, China
- Scientific Observing and Experimental Station of Environment Controlled Agricultural Engineering in Huang-Huai-Hai Region, Ministry of Agriculture and Rural Affairs, Taian, 271018, China
- State Key Laboratory of Crop Biology, Taian, 271018, China
- Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production in Shandong, Taian, 271018, China
| | - Chunhua Chen
- College of Horticultural Science and Engineering, Shandong Agricultural University, Taian, 271018, China
- State Key Laboratory of Crop Biology, Taian, 271018, China
- Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production in Shandong, Taian, 271018, China
| | - Yan Li
- College of Horticultural Science and Engineering, Shandong Agricultural University, Taian, 271018, China
- Scientific Observing and Experimental Station of Environment Controlled Agricultural Engineering in Huang-Huai-Hai Region, Ministry of Agriculture and Rural Affairs, Taian, 271018, China
- State Key Laboratory of Crop Biology, Taian, 271018, China
- Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production in Shandong, Taian, 271018, China
| | - Min Wei
- College of Horticultural Science and Engineering, Shandong Agricultural University, Taian, 271018, China.
- Scientific Observing and Experimental Station of Environment Controlled Agricultural Engineering in Huang-Huai-Hai Region, Ministry of Agriculture and Rural Affairs, Taian, 271018, China.
- State Key Laboratory of Crop Biology, Taian, 271018, China.
- Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production in Shandong, Taian, 271018, China.
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Christian R, Labbancz J, Usadel B, Dhingra A. Understanding protein import in diverse non-green plastids. Front Genet 2023; 14:969931. [PMID: 37007964 PMCID: PMC10063809 DOI: 10.3389/fgene.2023.969931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 02/24/2023] [Indexed: 03/19/2023] Open
Abstract
The spectacular diversity of plastids in non-green organs such as flowers, fruits, roots, tubers, and senescing leaves represents a Universe of metabolic processes in higher plants that remain to be completely characterized. The endosymbiosis of the plastid and the subsequent export of the ancestral cyanobacterial genome to the nuclear genome, and adaptation of the plants to all types of environments has resulted in the emergence of diverse and a highly orchestrated metabolism across the plant kingdom that is entirely reliant on a complex protein import and translocation system. The TOC and TIC translocons, critical for importing nuclear-encoded proteins into the plastid stroma, remain poorly resolved, especially in the case of TIC. From the stroma, three core pathways (cpTat, cpSec, and cpSRP) may localize imported proteins to the thylakoid. Non-canonical routes only utilizing TOC also exist for the insertion of many inner and outer membrane proteins, or in the case of some modified proteins, a vesicular import route. Understanding this complex protein import system is further compounded by the highly heterogeneous nature of transit peptides, and the varying transit peptide specificity of plastids depending on species and the developmental and trophic stage of the plant organs. Computational tools provide an increasingly sophisticated means of predicting protein import into highly diverse non-green plastids across higher plants, which need to be validated using proteomics and metabolic approaches. The myriad plastid functions enable higher plants to interact and respond to all kinds of environments. Unraveling the diversity of non-green plastid functions across the higher plants has the potential to provide knowledge that will help in developing climate resilient crops.
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Affiliation(s)
- Ryan Christian
- Department of Horticulture, Washington State University, Pullman, WA, United States
| | - June Labbancz
- Department of Horticulture, Washington State University, Pullman, WA, United States
- Department of Horticultural Sciences, Texas A&M University, College Station, TX, United States
| | | | - Amit Dhingra
- Department of Horticulture, Washington State University, Pullman, WA, United States
- Department of Horticultural Sciences, Texas A&M University, College Station, TX, United States
- *Correspondence: Amit Dhingra,
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Yu H, Wang Q, Zhang Z, Wu T, Yang X, Zhu X, Ye Y, Leng J, Yang S, Feng X. Genetic Mapping of the Gmpgl3 Mutant Reveals the Function of GmTic110a in Soybean Chloroplast Development. FRONTIERS IN PLANT SCIENCE 2022; 13:892077. [PMID: 35693168 PMCID: PMC9178232 DOI: 10.3389/fpls.2022.892077] [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: 03/08/2022] [Accepted: 05/09/2022] [Indexed: 06/15/2023]
Abstract
The generation of oxygen and organic matter in plants mainly depends on photosynthesis, which directly affects plant growth and development. The chloroplast is the main organelle in which photosynthesis occurs. In this study, a Glycine max pale green leaf 3-1 (Gmpgl3-1) mutant was isolated from the soybean mutagenized population. The Gmpgl3-1 mutant presented with decreased chlorophyll contents, reduced chloroplast stroma thylakoids, reduced yields, and decreased numbers of pods per plant. Bulked segregant analysis (BSA) together with map-based cloning revealed a single-nucleotide non-synonymous mutation at the 341st nucleotide of the first exon of the chloroplast development-related GmTic110a gene. The phenotype of the knockout plants was the same as that of the mutant. The GmTic110a gene was highly expressed in the leaves at various developmental stages, and its protein was localized to the inner chloroplast membrane. Split luciferase complementation assays and coimmunoprecipitation (co-IP) experiments revealed that GmTic110a interacted with GmTic20, GmTic40a, and GmTic40b in tobacco leaves. These results indicated that the GmTic110a gene plays an important role in chloroplast development.
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Affiliation(s)
- Hui Yu
- Key Laboratory of Soybean Molecular Design Breeding, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, China
| | - Qiushi Wang
- Key Laboratory of Soybean Molecular Design Breeding, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, China
| | - Zhirui Zhang
- Key Laboratory of Soybean Molecular Design Breeding, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Tao Wu
- Key Laboratory of Soybean Molecular Design Breeding, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Xinjing Yang
- Key Laboratory of Soybean Molecular Design Breeding, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Xiaobin Zhu
- Key Laboratory of Soybean Molecular Design Breeding, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Yongheng Ye
- Key Laboratory of Soybean Molecular Design Breeding, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Jiantian Leng
- Key Laboratory of Soybean Molecular Design Breeding, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, China
| | - Suxin Yang
- Key Laboratory of Soybean Molecular Design Breeding, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, China
| | - Xianzhong Feng
- Key Laboratory of Soybean Molecular Design Breeding, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
- Zhejiang Lab, Hangzhou, China
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Gene discovery and virus-induced gene silencing reveal branched pathways to major classes of bioactive diterpenoids in Euphorbia peplus. Proc Natl Acad Sci U S A 2022; 119:e2203890119. [PMID: 35584121 PMCID: PMC9173813 DOI: 10.1073/pnas.2203890119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
SignificanceEuphorbia peplus, a member of the Euphorbia genus, is rich in jatrophane and ingenane diterpenoids. Using a metabolomics-guided transcriptomic approach to gene candidate identification, we have discovered a short-chain dehydrogenase gene involved in the production of the lathyrane jolkinol E. We have developed a virus-induced gene-silencing method in E. peplus that has allowed us to demonstrate the direct relationship between casbene and polycyclic diterpenoids and that jolkinol C acts as a key branch point intermediate in the production of ingenanes and jatrophanes. This work contributes both knowledge and tools for engineering production of bioactive diterpenoids in heterologous host systems, thus enabling their further evaluation and development.
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9
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Chloroplast Protein Tic55 Involved in Dark-Induced Senescence through AtbHLH/AtWRKY-ANAC003 Controlling Pathway of Arabidopsis thaliana. Genes (Basel) 2022; 13:genes13020308. [PMID: 35205352 PMCID: PMC8872272 DOI: 10.3390/genes13020308] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 01/26/2022] [Accepted: 02/02/2022] [Indexed: 12/04/2022] Open
Abstract
The chloroplast comprises the outer and inner membranes that are composed of the translocon protein complexes Toc and Tic (translocon at the outer/inner envelope membrane of chloroplasts), respectively. Tic55, a chloroplast Tic protein member, was shown to be not vital for functional protein import in Arabidopsis from previous studies. Instead, Tic55 was revealed to be a dark-induced senescence-related protein in our earlier study. To explore whether Tic55 elicits other biological functions, a tic55-II knockout mutant (SALK_086048) was characterized under different stress treatments. Abiotic stress conditions, such as cold, heat, and high osmotic pressure, did not cause visible effects on tic55-II mutant plant, when compared to the wild type (WT). In contrast, senescence was induced in the individually darkened leaves (IDLs), resulting in the differential expression of the senescence-related genes PEROXISOME DEFECTIVE 1 (PED1), BLUE COPPER-BINDING PROTEIN (BCB), SENESCENCE 1 (SEN1), and RUBISCO SMALL SUBUNIT GENE 2B (RBCS2B). The absence of Tic55 in tic55-II knockout mutant inhibited expression of the senescence-related genes PED1, BCB, and SEN1 at different stages of dark adaptation, while causing stimulation of RBCS2B gene expression at an early stage of dark response. Finally, yeast one-hybrid assays located the ANAC003 promoter region with cis-acting elements are responsible for binding to the different AtbHLH proteins, thereby causing the transactivation of an HIS3 reporter gene. ANAC003 was shown previously as a senescence-related protein and its activation would lead to expression of senescence-associated genes (SAGs), resulting in plant senescence. Thus, we propose a hypothetical model in which three signaling pathways may be involved in controlling the expression of ANAC003, followed by expression of SAGs that in turn leads to leaf senescence in Arabidopsis by this study and previous data.
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10
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Li C, Liu Y, Liu X, Mai KKK, Li J, Guo X, Zhang C, Li H, Kang BH, Hwang I, Lu H. Chloroplast thylakoid ascorbate peroxidase PtotAPX plays a key role in chloroplast development by decreasing hydrogen peroxide in Populus tomentosa. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:4333-4354. [PMID: 33884422 DOI: 10.1093/jxb/erab173] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 04/17/2021] [Indexed: 06/12/2023]
Abstract
Chloroplast development is a complex process that is critical to the growth and development of plants. However, the detailed mechanism of chloroplast development in woody plants remains unclear. In this study, we showed that chloroplasts with elaborate thylakoids could develop from proplastids in the cells of calli derived from leaf tissues of Populus tomentosa upon exposure to light. Chloroplast development was confirmed at the molecular and cellular levels. Transcriptome analysis revealed that genes related to photoreceptors and photosynthesis were significantly up-regulated during chloroplast development in a time-dependent manner. In light-induced chloroplast development, a key process was the removal of hydrogen peroxide, in which thylakoid-localized PtotAPX played a major role; light-induced chloroplast development was enhanced in PtotAPX-overexpressing transgenic P. tomentosa callus with lower levels of hydrogen peroxide, but was suppressed in PtotAPX antisense transgenic callus with higher levels of hydrogen peroxide. Moreover, the suppression of light-induced chloroplast development in PtotAPX antisense transgenic callus was relieved by the exogenous reactive oxygen species scavenging agent N,N'-dimethylthiourea (DMTU). Based on these results, we propose that PtotAPX-mediated removal of reactive oxygen species plays a key role in chloroplast development from proplastids upon exposure to light in P. tomentosa.
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Affiliation(s)
- Conghui Li
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing, China
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
| | - Yadi Liu
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing, China
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
| | - Xiatong Liu
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing, China
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
| | - Keith Ka Ki Mai
- Centre for Cell and Developmental Biology, State Key Laboratory for Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Jiaxin Li
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
| | - Xiaorui Guo
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing, China
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
| | - Chong Zhang
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
| | - Hui Li
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing, China
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
| | - Byung-Ho Kang
- Centre for Cell and Developmental Biology, State Key Laboratory for Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Inhwan Hwang
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology (POSTECH), Pohang, South Korea
| | - Hai Lu
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing, China
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
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11
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Yuan H, Pawlowski EG, Yang Y, Sun T, Thannhauser TW, Mazourek M, Schnell D, Li L. Arabidopsis ORANGE protein regulates plastid pre-protein import through interacting with Tic proteins. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:1059-1072. [PMID: 33165598 DOI: 10.1093/jxb/eraa528] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 10/30/2020] [Indexed: 05/19/2023]
Abstract
Chloroplast-targeted proteins are actively imported into chloroplasts via the machinery spanning the double-layered membranes of chloroplasts. While the key translocons at the outer (TOC) and inner (TIC) membranes of chloroplasts are defined, proteins that interact with the core components to facilitate pre-protein import are continuously being discovered. A DnaJ-like chaperone ORANGE (OR) protein is known to regulate carotenoid biosynthesis as well as plastid biogenesis and development. In this study, we found that OR physically interacts with several Tic proteins including Tic20, Tic40, and Tic110 in the classic TIC core complex of the chloroplast import machinery. Knocking out or and its homolog or-like greatly affects the import efficiency of some photosynthetic and non-photosynthetic pre-proteins. Consistent with the direct interactions of OR with Tic proteins, the binding efficiency assay revealed that the effect of OR occurs at translocation at the inner envelope membrane (i.e. at the TIC complex). OR is able to reduce the Tic40 protein turnover rate through its chaperone activity. Moreover, OR was found to interfere with the interaction between Tic40 and Tic110, and reduces the binding of pre-proteins to Tic110 in aiding their release for translocation and processing. Our findings suggest that OR plays a new and regulatory role in stabilizing key translocons and in facilitating the late stage of plastid pre-protein translocation to regulate plastid pre-protein import.
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Affiliation(s)
- Hui Yuan
- Robert W. Holley Center for Agriculture and Health, USDA-ARS, Cornell University, Ithaca, NY, USA
- Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, USA
| | - Emily G Pawlowski
- Department of Plant Biology, Michigan State University, East Lansing, MI, USA
| | - Yong Yang
- Robert W. Holley Center for Agriculture and Health, USDA-ARS, Cornell University, Ithaca, NY, USA
| | - Tianhu Sun
- Robert W. Holley Center for Agriculture and Health, USDA-ARS, Cornell University, Ithaca, NY, USA
- Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, USA
| | - Theodore W Thannhauser
- Robert W. Holley Center for Agriculture and Health, USDA-ARS, Cornell University, Ithaca, NY, USA
| | - Michael Mazourek
- Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, USA
| | - Danny Schnell
- Department of Plant Biology, Michigan State University, East Lansing, MI, USA
| | - Li Li
- Robert W. Holley Center for Agriculture and Health, USDA-ARS, Cornell University, Ithaca, NY, USA
- Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, USA
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12
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Marshall JW, de Mattos-Shipley KMJ, Ghannam IAY, Munawar A, Killen JC, Lazarus CM, Cox RJ, Willis CL, Simpson TJ. Fusarochromene, a novel tryptophan-derived metabolite from Fusarium sacchari. Org Biomol Chem 2021; 19:182-187. [PMID: 33107888 DOI: 10.1039/d0ob02031a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Fusarochromene isolated from the plant pathogenic fungus, Fusarium sacchari is closely related to a group of mycotoxins including fusarochromanone previously isolated from various Fusaria spp. Despite their assumed polyketide biogenesis, incorporation studies with 13C-labelled acetate, glycerol and tryptophans show that fusarochromene is unexpectedly derived via oxidative cleavage of the aromatic amino acid tryptophan. A putative biosynthetic gene cluster has been identified.
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Affiliation(s)
- James W Marshall
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK.
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13
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Müller JT, van Veen H, Bartylla MM, Akman M, Pedersen O, Sun P, Schuurink RC, Takeuchi J, Todoroki Y, Weig AR, Sasidharan R, Mustroph A. Keeping the shoot above water - submergence triggers antithetical growth responses in stems and petioles of watercress (Nasturtium officinale). THE NEW PHYTOLOGIST 2021; 229:140-155. [PMID: 31792981 DOI: 10.1111/nph.16350] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 11/26/2019] [Indexed: 05/25/2023]
Abstract
The molecular mechanisms controlling underwater elongation are based extensively on studies on internode elongation in the monocot rice (Oryza sativa) and petiole elongation in Rumex rosette species. Here, we characterize underwater growth in the dicot Nasturtium officinale (watercress), a wild species of the Brassicaceae family, in which submergence enhances stem elongation and suppresses petiole growth. We used a genome-wide transcriptome analysis to identify the molecular mechanisms underlying the observed antithetical growth responses. Though submergence caused a substantial reconfiguration of the petiole and stem transcriptome, only little qualitative differences were observed between both tissues. A core submergence response included hormonal regulation and metabolic readjustment for energy conservation, whereas tissue-specific responses were associated with defense, photosynthesis, and cell wall polysaccharides. Transcriptomic and physiological characterization suggested that the established ethylene, abscisic acid (ABA), and GA growth regulatory module for underwater elongation could not fully explain underwater growth in watercress. Petiole growth suppression is likely attributed to a cell cycle arrest. Underwater stem elongation is driven by an early decline in ABA and is not primarily mediated by ethylene or GA. An enhanced stem elongation observed in the night period was not linked to hypoxia and suggests an involvement of circadian regulation.
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Affiliation(s)
- Jana T Müller
- Plant Physiology, University Bayreuth, Universitaetsstraße 30, 95440, Bayreuth, Germany
| | - Hans van Veen
- Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, the Netherlands
| | - Malte M Bartylla
- Plant Physiology, University Bayreuth, Universitaetsstraße 30, 95440, Bayreuth, Germany
| | - Melis Akman
- Plant and Microbial Biology, University of California, Berkeley, 361 Koshland Hall, Berkeley, CA, 94720, USA
- Plant Sciences, University of California, Davis, One Shields Avenue, Davis, CA, 95616, USA
| | - Ole Pedersen
- Department of Biology, University of Copenhagen, Universitetsparken 4, 2100, Copenhagen, Denmark
| | - Pulu Sun
- Green Life Sciences Research Cluster, Swammerdam Institute for Life Sciences, University of Amsterdam, 1098 XH, Amsterdam, the Netherlands
| | - Robert C Schuurink
- Green Life Sciences Research Cluster, Swammerdam Institute for Life Sciences, University of Amsterdam, 1098 XH, Amsterdam, the Netherlands
| | - Jun Takeuchi
- Faculty of Agriculture, Shizuoka University, Shizuoka, 422-8529, Japan
| | - Yasushi Todoroki
- Faculty of Agriculture, Shizuoka University, Shizuoka, 422-8529, Japan
| | - Alfons R Weig
- Genomics & Bioinformatics, University Bayreuth, Universitaetsstraße 30, 95440, Bayreuth, Germany
| | - Rashmi Sasidharan
- Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, the Netherlands
| | - Angelika Mustroph
- Plant Physiology, University Bayreuth, Universitaetsstraße 30, 95440, Bayreuth, Germany
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14
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Ramundo S, Asakura Y, Salomé PA, Strenkert D, Boone M, Mackinder LCM, Takafuji K, Dinc E, Rahire M, Crèvecoeur M, Magneschi L, Schaad O, Hippler M, Jonikas MC, Merchant S, Nakai M, Rochaix JD, Walter P. Coexpressed subunits of dual genetic origin define a conserved supercomplex mediating essential protein import into chloroplasts. Proc Natl Acad Sci U S A 2020; 117:32739-32749. [PMID: 33273113 PMCID: PMC7768757 DOI: 10.1073/pnas.2014294117] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
In photosynthetic eukaryotes, thousands of proteins are translated in the cytosol and imported into the chloroplast through the concerted action of two translocons-termed TOC and TIC-located in the outer and inner membranes of the chloroplast envelope, respectively. The degree to which the molecular composition of the TOC and TIC complexes is conserved over phylogenetic distances has remained controversial. Here, we combine transcriptomic, biochemical, and genetic tools in the green alga Chlamydomonas (Chlamydomonas reinhardtii) to demonstrate that, despite a lack of evident sequence conservation for some of its components, the algal TIC complex mirrors the molecular composition of a TIC complex from Arabidopsis thaliana. The Chlamydomonas TIC complex contains three nuclear-encoded subunits, Tic20, Tic56, and Tic100, and one chloroplast-encoded subunit, Tic214, and interacts with the TOC complex, as well as with several uncharacterized proteins to form a stable supercomplex (TIC-TOC), indicating that protein import across both envelope membranes is mechanistically coupled. Expression of the nuclear and chloroplast genes encoding both known and uncharacterized TIC-TOC components is highly coordinated, suggesting that a mechanism for regulating its biogenesis across compartmental boundaries must exist. Conditional repression of Tic214, the only chloroplast-encoded subunit in the TIC-TOC complex, impairs the import of chloroplast proteins with essential roles in chloroplast ribosome biogenesis and protein folding and induces a pleiotropic stress response, including several proteins involved in the chloroplast unfolded protein response. These findings underscore the functional importance of the TIC-TOC supercomplex in maintaining chloroplast proteostasis.
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Affiliation(s)
- Silvia Ramundo
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143
- Howard Hughes Medical Institute, Chevy Chase, MD 20815
| | - Yukari Asakura
- Laboratory of Organelle Biology, Institute for Protein Research, Osaka University, Osaka 565-0871, Japan
| | - Patrice A Salomé
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095
| | - Daniela Strenkert
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095
| | - Morgane Boone
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143
- Howard Hughes Medical Institute, Chevy Chase, MD 20815
| | - Luke C M Mackinder
- Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Kazuaki Takafuji
- Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan
| | - Emine Dinc
- Department of Molecular Biology, University of Geneva, Geneva CH-1211, Switzerland
- Department of Plant Biology, University of Geneva, Geneva CH-1211, Switzerland
| | - Michèle Rahire
- Department of Molecular Biology, University of Geneva, Geneva CH-1211, Switzerland
- Department of Plant Biology, University of Geneva, Geneva CH-1211, Switzerland
| | - Michèle Crèvecoeur
- Department of Molecular Biology, University of Geneva, Geneva CH-1211, Switzerland
- Department of Plant Biology, University of Geneva, Geneva CH-1211, Switzerland
| | - Leonardo Magneschi
- Institute of Plant Biology and Biotechnology, University of Münster, Münster 48143, Germany
| | - Olivier Schaad
- Department of Biochemistry, University of Geneva, Geneva CH-1211, Switzerland
| | - Michael Hippler
- Institute of Plant Biology and Biotechnology, University of Münster, Münster 48143, Germany
- Institute of Plant Science and Resources, Okayama University, Kurashiki 710-0046, Japan
| | - Martin C Jonikas
- Department of Molecular Biology, Princeton University, Princeton, NJ 08540
- Howard Hughes Medical Institute, Chevy Chase, MD 20815
| | - Sabeeha Merchant
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095
| | - Masato Nakai
- Laboratory of Organelle Biology, Institute for Protein Research, Osaka University, Osaka 565-0871, Japan;
| | - Jean-David Rochaix
- Department of Molecular Biology, University of Geneva, Geneva CH-1211, Switzerland;
- Department of Plant Biology, University of Geneva, Geneva CH-1211, Switzerland
| | - Peter Walter
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143;
- Howard Hughes Medical Institute, Chevy Chase, MD 20815
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15
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The Direct Involvement of Dark-Induced Tic55 Protein in Chlorophyll Catabolism and Its Indirect Role in the MYB108-NAC Signaling Pathway during Leaf Senescence in Arabidopsis thaliana. Int J Mol Sci 2018; 19:ijms19071854. [PMID: 29937503 PMCID: PMC6073118 DOI: 10.3390/ijms19071854] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 06/19/2018] [Accepted: 06/21/2018] [Indexed: 11/23/2022] Open
Abstract
The chloroplast relies on proteins encoded in the nucleus, synthesized in the cytosol and subsequently transported into chloroplast through the protein complexes Toc and Tic (Translocon at the outer/inner membrane of chloroplasts). A Tic complex member, Tic55, contains a redox-related motif essential for protein import into chloroplasts in peas. However, Tic55 is not crucial for protein import in Arabidopsis. Here, a tic55-II-knockout mutant of Arabidopsis thaliana was characterized for Tic55 localization, its relationship with other translocon proteins, and its association with plant leaf senescence when compared to the wild type. Individually darkened leaves (IDLs) obtained through dark-induced leaf senescence were used to demonstrate chlorophyll breakdown and its relationship with plant senescence in the tic55-II-knockout mutant. The IDLs of the tic55-II-knockout mutant contained higher chlorophyll concentrations than those of the wild type. Our microarray analysis of IDLs during leaf senescence identified seven senescence-associated genes (SAGs) that were downregulated in the tic55-II-knockout mutant: ASP3, APG7, DIN2, DIN11, SAG12, SAG13, and YLS9. Real-time quantitative PCR confirmed the reliability of microarray analysis by showing the same expression patterns with those of the microarray data. Thus, Tic55 functions in dark-induced aging in A. thaliana by indirectly regulating downstream SAGs expression. In addition, the expression of four NAC genes, including ANAC003, ANAC010, ANAC042, and ANAC075 of IDL treated tic55-II-knockout mutant appeared to be downregulated. Yeast one hybrid assay revealed that only ANAC003 promoter region can be bound by MYB108, suggesting that a MYB-NAC regulatory network is involved in dark-stressed senescence.
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16
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Jayakodi M, Lee SC, Yang TJ. Comparative transcriptome analysis of heat stress responsiveness between two contrasting ginseng cultivars. J Ginseng Res 2018; 43:572-579. [PMID: 31700259 PMCID: PMC6823803 DOI: 10.1016/j.jgr.2018.05.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Revised: 05/16/2018] [Accepted: 05/28/2018] [Indexed: 02/01/2023] Open
Abstract
Background Panax ginseng has been used in traditional medicine to strengthen the body and mental well-being of humans for thousands of years. Many elite ginseng cultivars have been developed, and ginseng cultivation has become well established during the last century. However, heat stress poses an important threat to the growth and sustainable production of ginseng. Efforts have been made to study the effects of high temperature on ginseng physiology, but knowledge of the molecular responses to heat stress is still limited. Methods We sequenced the transcriptomes (RNA-Seq) of two ginseng cultivars, Chunpoong (CP) and Yunpoong (YP), which are sensitive and resistant to heat stress, respectively, after 1- and 3-week heat treatments. Differential gene expression and gene ontology enrichment along with profiled chlorophyll contents were performed. Results CP is more sensitive to heat stress than YP and exhibited a lower chlorophyll content than YP. Moreover, heat stress reduced the chlorophyll content more rapidly in CP than in YP. A total of 329 heat-responsive genes were identified. Intriguingly, genes encoding chlorophyll a/b–binding proteins, WRKY transcription factors, and fatty acid desaturase were predominantly responsive during heat stress and appeared to regulate photosynthesis. In addition, a genome-wide scan of photosynthetic and sugar metabolic genes revealed reduced transcription levels for ribulose 1,5-bisphosphate carboxylase/oxygenase under heat stress, especially in CP, possibly attributable to elevated levels of soluble sugars. Conclusion Our comprehensive genomic analysis reveals candidate loci/gene targets for breeding and functional studies related to developing high temperature–tolerant ginseng varieties.
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Affiliation(s)
- Murukarthick Jayakodi
- Department of Plant Science, Plant Genomics and Breeding Institute, and Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea
| | - Sang-Choon Lee
- Department of Plant Science, Plant Genomics and Breeding Institute, and Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea
| | - Tae-Jin Yang
- Department of Plant Science, Plant Genomics and Breeding Institute, and Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea
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17
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Belbin FE, Noordally ZB, Wetherill SJ, Atkins KA, Franklin KA, Dodd AN. Integration of light and circadian signals that regulate chloroplast transcription by a nuclear-encoded sigma factor. THE NEW PHYTOLOGIST 2017; 213:727-738. [PMID: 27716936 PMCID: PMC5215360 DOI: 10.1111/nph.14176] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 07/28/2016] [Indexed: 05/19/2023]
Abstract
We investigated the signalling pathways that regulate chloroplast transcription in response to environmental signals. One mechanism controlling plastid transcription involves nuclear-encoded sigma subunits of plastid-encoded plastid RNA polymerase. Transcripts encoding the sigma factor SIG5 are regulated by light and the circadian clock. However, the extent to which a chloroplast target of SIG5 is regulated by light-induced changes in SIG5 expression is unknown. Moreover, the photoreceptor signalling pathways underlying the circadian regulation of chloroplast transcription by SIG5 are unidentified. We monitored the regulation of chloroplast transcription in photoreceptor and sigma factor mutants under controlled light regimes in Arabidopsis thaliana. We established that a chloroplast transcriptional response to light intensity was mediated by SIG5; a chloroplast transcriptional response to the relative proportions of red and far red light was regulated by SIG5 through phytochrome and photosynthetic signals; and the circadian regulation of chloroplast transcription by SIG5 was predominantly dependent on blue light and cryptochrome. Our experiments reveal the extensive integration of signals concerning the light environment by a single sigma factor to regulate chloroplast transcription. This may originate from an evolutionarily ancient mechanism that protects photosynthetic bacteria from high light stress, which subsequently became integrated with higher plant phototransduction networks.
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Affiliation(s)
- Fiona E. Belbin
- School of Biological SciencesUniversity of BristolBristol Life Sciences Building, 24 Tyndall AvenueBristolBS8 1TQUK
| | - Zeenat B. Noordally
- Department of Botany and Plant BiologyUniversity of GenevaGenevaCH‐1211Switzerland
| | | | - Kelly A. Atkins
- School of Biological SciencesUniversity of BristolBristol Life Sciences Building, 24 Tyndall AvenueBristolBS8 1TQUK
| | - Keara A. Franklin
- School of Biological SciencesUniversity of BristolBristol Life Sciences Building, 24 Tyndall AvenueBristolBS8 1TQUK
| | - Antony N. Dodd
- School of Biological SciencesUniversity of BristolBristol Life Sciences Building, 24 Tyndall AvenueBristolBS8 1TQUK
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18
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Sjuts I, Soll J, Bölter B. Import of Soluble Proteins into Chloroplasts and Potential Regulatory Mechanisms. FRONTIERS IN PLANT SCIENCE 2017; 8:168. [PMID: 28228773 PMCID: PMC5296341 DOI: 10.3389/fpls.2017.00168] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 01/26/2017] [Indexed: 05/20/2023]
Abstract
Chloroplasts originated from an endosymbiotic event in which a free-living cyanobacterium was engulfed by an ancestral eukaryotic host. During evolution the majority of the chloroplast genetic information was transferred to the host cell nucleus. As a consequence, proteins formerly encoded by the chloroplast genome are now translated in the cytosol and must be subsequently imported into the chloroplast. This process involves three steps: (i) cytosolic sorting procedures, (ii) binding to the designated receptor-equipped target organelle and (iii) the consecutive translocation process. During import, proteins have to overcome the two barriers of the chloroplast envelope, namely the outer envelope membrane (OEM) and the inner envelope membrane (IEM). In the majority of cases, this is facilitated by two distinct multiprotein complexes, located in the OEM and IEM, respectively, designated TOC and TIC. Plants are constantly exposed to fluctuating environmental conditions such as temperature and light and must therefore regulate protein composition within the chloroplast to ensure optimal functioning of elementary processes such as photosynthesis. In this review we will discuss the recent models of each individual import stage with regard to short-term strategies that plants might use to potentially acclimate to changes in their environmental conditions and preserve the chloroplast protein homeostasis.
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Affiliation(s)
- Inga Sjuts
- Department Biologie I-Botanik, Ludwig-Maximilians-UniversitätPlanegg-Martinsried, Germany
| | - Jürgen Soll
- Department Biologie I-Botanik, Ludwig-Maximilians-UniversitätPlanegg-Martinsried, Germany
- Munich Center for Integrated Protein Science CiPSM, Ludwig-Maximilians-UniversitätMunich, Germany
| | - Bettina Bölter
- Department Biologie I-Botanik, Ludwig-Maximilians-UniversitätPlanegg-Martinsried, Germany
- Munich Center for Integrated Protein Science CiPSM, Ludwig-Maximilians-UniversitätMunich, Germany
- *Correspondence: Bettina Bölter,
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19
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No plastidial calmodulin-like proteins detected by two targeted mass-spectrometry approaches and GFP fusion proteins. ACTA ACUST UNITED AC 2016. [DOI: 10.1016/j.neps.2016.08.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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20
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Bölter B, Soll J. Once upon a Time - Chloroplast Protein Import Research from Infancy to Future Challenges. MOLECULAR PLANT 2016; 9:798-812. [PMID: 27142186 DOI: 10.1016/j.molp.2016.04.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 04/25/2016] [Accepted: 04/27/2016] [Indexed: 05/08/2023]
Abstract
Protein import into chloroplasts has been a focus of research for several decades. The first publications dealing with this fascinating topic appeared in the 1970s. From the initial realization that many plastid proteins are being encoded for in the nucleus and require transport into their target organelle to the identification of import components in the cytosol, chloroplast envelopes, and stroma, as well as elucidation of some mechanistic details, more fascinating aspects are still being unraveled. With this overview, we present a survey of the beginnings of chloroplast protein import research, the first steps on this winding road, and end with a glimpse into the future.
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Affiliation(s)
- Bettina Bölter
- Department Biologie I-Botanik, Ludwig-Maximilians-Universität, Großhaderner Straße 2-4, 82152 Planegg-Martinsried, Germany; Munich Center for Integrated Protein Science CiPSM, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 25, 81377 Munich, Germany.
| | - Jürgen Soll
- Department Biologie I-Botanik, Ludwig-Maximilians-Universität, Großhaderner Straße 2-4, 82152 Planegg-Martinsried, Germany; Munich Center for Integrated Protein Science CiPSM, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 25, 81377 Munich, Germany
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21
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Bölter B, Soll J, Schwenkert S. Redox meets protein trafficking. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:949-56. [PMID: 25626173 DOI: 10.1016/j.bbabio.2015.01.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 01/16/2015] [Accepted: 01/19/2015] [Indexed: 11/15/2022]
Abstract
After the engulfment of two prokaryotic organisms, the thus emerged eukaryotic cell needed to establish means of communication and signaling to properly integrate the acquired organelles into its metabolism. Regulatory mechanisms had to evolve to ensure that chloroplasts and mitochondria smoothly function in accordance with all other cellular processes. One essential process is the post-translational import of nuclear encoded organellar proteins, which needs to be adapted according to the requirements of the plant. The demand for protein import is constantly changing depending on varying environmental conditions, as well as external and internal stimuli or different developmental stages. Apart from long-term regulatory mechanisms such as transcriptional/translation control, possibilities for short-term acclimation are mandatory. To this end, protein import is integrated into the cellular redox network, utilizing the recognition of signals from within the organelles and modifying the efficiency of the translocon complexes. Thereby, cellular requirements can be communicated throughout the whole organism. This article is part of a Special Issue entitled: Chloroplast Biogenesis.
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Affiliation(s)
- Bettina Bölter
- Department Biologie I-Botanik, Ludwig-Maximilians-Universität, Großhadernerstr. 2-4, D-82152 Planegg-Martinsried, Germany; Munich Center for Integrated Protein Science CiPSM, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 25, D-81377 Munich, Germany
| | - Jürgen Soll
- Department Biologie I-Botanik, Ludwig-Maximilians-Universität, Großhadernerstr. 2-4, D-82152 Planegg-Martinsried, Germany; Munich Center for Integrated Protein Science CiPSM, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 25, D-81377 Munich, Germany.
| | - Serena Schwenkert
- Department Biologie I-Botanik, Ludwig-Maximilians-Universität, Großhadernerstr. 2-4, D-82152 Planegg-Martinsried, Germany; Munich Center for Integrated Protein Science CiPSM, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 25, D-81377 Munich, Germany
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Parker N, Wang Y, Meinke D. Natural variation in sensitivity to a loss of chloroplast translation in Arabidopsis. PLANT PHYSIOLOGY 2014; 166:2013-27. [PMID: 25336520 PMCID: PMC4256881 DOI: 10.1104/pp.114.249052] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Mutations that eliminate chloroplast translation in Arabidopsis (Arabidopsis thaliana) result in embryo lethality. The stage of embryo arrest, however, can be influenced by genetic background. To identify genes responsible for improved growth in the absence of chloroplast translation, we examined seedling responses of different Arabidopsis accessions on spectinomycin, an inhibitor of chloroplast translation, and crossed the most tolerant accessions with embryo-defective mutants disrupted in chloroplast ribosomal proteins generated in a sensitive background. The results indicate that tolerance is mediated by ACC2, a duplicated nuclear gene that targets homomeric acetyl-coenzyme A carboxylase to plastids, where the multidomain protein can participate in fatty acid biosynthesis. In the presence of functional ACC2, tolerance is enhanced by a second locus that maps to chromosome 5 and heightened by additional genetic modifiers present in the most tolerant accessions. Notably, some of the most sensitive accessions contain nonsense mutations in ACC2, including the "Nossen" line used to generate several of the mutants studied here. Functional ACC2 protein is therefore not required for survival in natural environments, where heteromeric acetyl-coenzyme A carboxylase encoded in part by the chloroplast genome can function instead. This work highlights an interesting example of a tandem gene duplication in Arabidopsis, helps to explain the range of embryo phenotypes found in Arabidopsis mutants disrupted in essential chloroplast functions, addresses the nature of essential proteins encoded by the chloroplast genome, and underscores the value of using natural variation to study the relationship between chloroplast translation, plant metabolism, protein import, and plant development.
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Affiliation(s)
- Nicole Parker
- Department of Botany, Oklahoma State University, Stillwater, Oklahoma 74078
| | - Yixing Wang
- Department of Botany, Oklahoma State University, Stillwater, Oklahoma 74078
| | - David Meinke
- Department of Botany, Oklahoma State University, Stillwater, Oklahoma 74078
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23
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Tada A, Adachi F, Kakizaki T, Inaba T. Production of viable seeds from the seedling lethal mutant ppi2-2 lacking the atToc159 chloroplast protein import receptor using plastic containers, and characterization of the homozygous mutant progeny. FRONTIERS IN PLANT SCIENCE 2014; 5:243. [PMID: 24926298 PMCID: PMC4045241 DOI: 10.3389/fpls.2014.00243] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Accepted: 05/13/2014] [Indexed: 05/18/2023]
Abstract
Biogenesis of chloroplasts is essential for plant growth and development. A number of homozygous mutants lacking a chloroplast protein exhibit an albino phenotype. In general, it is challenging to grow albino Arabidopsis plants on soil until they set seeds. Homozygous albino mutants are usually obtained as progenies of heterozygous parents. Here, we describe a method of recovering seeds from the seedling lethal Arabidopsis mutant ppi2-2, which lacks the atToc159 protein import receptor at the outer envelope membrane of chloroplast. Using plastic containers, we were able to grow homozygous ppi2-2 plants until these set seed. Although the germination rate of the harvested seeds was relatively low, it was still sufficient to allow us to further analyze the ppi2-2 progeny. Using ppi2-2 homozygous seeds, we were able to analyze the role of plastid protein import in the light-regulated induction of nuclear genes. We propose that this method be applied to other seedling lethal Arabidopsis mutants to obtain homozygous seeds, helping us further investigate the roles of plastid proteins in plant growth and development.
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Affiliation(s)
- Akari Tada
- Department of Agricultural and Environmental Sciences, Faculty of Agriculture, University of MiyazakiMiyazaki, Japan
| | - Fumi Adachi
- Department of Agricultural and Environmental Sciences, Faculty of Agriculture, University of MiyazakiMiyazaki, Japan
| | | | - Takehito Inaba
- Department of Agricultural and Environmental Sciences, Faculty of Agriculture, University of MiyazakiMiyazaki, Japan
- *Correspondence: Takehito Inaba, Department of Agricultural and Environmental Sciences, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuenkibanadai-nishi, Miyazaki 889-2192, Japan e-mail:
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24
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Shi LX, Theg SM. The chloroplast protein import system: from algae to trees. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1833:314-31. [PMID: 23063942 DOI: 10.1016/j.bbamcr.2012.10.002] [Citation(s) in RCA: 138] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Revised: 09/07/2012] [Accepted: 10/01/2012] [Indexed: 01/15/2023]
Abstract
Chloroplasts are essential organelles in the cells of plants and algae. The functions of these specialized plastids are largely dependent on the ~3000 proteins residing in the organelle. Although chloroplasts are capable of a limited amount of semiautonomous protein synthesis - their genomes encode ~100 proteins - they must import more than 95% of their proteins after synthesis in the cytosol. Imported proteins generally possess an N-terminal extension termed a transit peptide. The importing translocons are made up of two complexes in the outer and inner envelope membranes, the so-called Toc and Tic machineries, respectively. The Toc complex contains two precursor receptors, Toc159 and Toc34, a protein channel, Toc75, and a peripheral component, Toc64/OEP64. The Tic complex consists of as many as eight components, namely Tic22, Tic110, Tic40, Tic20, Tic21 Tic62, Tic55 and Tic32. This general Toc/Tic import pathway, worked out largely in pea chloroplasts, appears to operate in chloroplasts in all green plants, albeit with significant modifications. Sub-complexes of the Toc and Tic machineries are proposed to exist to satisfy different substrate-, tissue-, cell- and developmental requirements. In this review, we summarize our understanding of the functions of Toc and Tic components, comparing these components of the import machinery in green algae through trees. We emphasize recent findings that point to growing complexities of chloroplast protein import process, and use the evolutionary relationships between proteins of different species in an attempt to define the essential core translocon components and those more likely to be responsible for regulation. This article is part of a Special Issue entitled: Protein Import and Quality Control in Mitochondria and Plastids.
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Affiliation(s)
- Lan-Xin Shi
- Department of Plant Biology, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA.
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25
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Grewal RK, Gupta S, Das S. Xanthomonas oryzae pv oryzae triggers immediate transcriptomic modulations in rice. BMC Genomics 2012; 13:49. [PMID: 22289642 PMCID: PMC3298507 DOI: 10.1186/1471-2164-13-49] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2011] [Accepted: 01/31/2012] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Xanthomonas oryzae pv oryzae is a devastating pathogen of rice and has been extensively studied as a model pathogen of monocotyledons. Expressional studies in both the contenders have been undertaken in past to understand the molecular mechanism underlying the compatible and incompatible interactions in the pathosystem. Continuous update on database and gene annotations necessitates constant updating on the roles of the new entities as well as reinterpretation of regulations of the previous ones. Moreover the past endeavors have addressed the middle or late defense responses of the rice plant whereas in the present study an attempt has been made to investigate the early defense responses taking place immediately after inoculation. RESULTS Microarray was used to study the transcriptional modulations in eighteen days old rice seedling leaves of both susceptible and resistant genotypes one hour after inoculation. In resistant plants as compared to susceptible ones 274 genes were found to be differentially expressed. Annotations could be assigned to 112 up- and 73 down-regulated transcripts and gene interaction maps were generated for 86 transcripts. Expressional data and interaction maps were used to develop a hypothetical scheme of the molecular events taking place during early defense response. Network analysis with the differential transcripts showed up-regulation of major clusters of cell signaling proteins and transcription factors while growth and basal metabolic components were largely found to be down-regulated. CONCLUSIONS This study provides an understanding of the early defense signaling in rice cells. Components of the calcium and lipid signaling as well as MAPK cascade were modulated, by signals from surface receptors and cytosolic R-proteins, to arouse jasmonic acid and ethylene signaling and suppress auxin signaling through various transcription factors. Abscisic acid modulation was also evident through the expression regulation of transcription factors involved with its functions. Moreover adjustments in expression levels of components of primary as well as secondary metabolism, protein trafficking and turnout were apparent, highlighting the complexity of defense response.
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Affiliation(s)
- Rumdeep K Grewal
- Division of Plant Biology, Bose Institute, Centenary Campus, P1/12 C.I.T. Scheme VII M, Kankurgachi, Kolkata-700054, India
| | - Sumanti Gupta
- Division of Plant Biology, Bose Institute, Centenary Campus, P1/12 C.I.T. Scheme VII M, Kankurgachi, Kolkata-700054, India
| | - Sampa Das
- Division of Plant Biology, Bose Institute, Centenary Campus, P1/12 C.I.T. Scheme VII M, Kankurgachi, Kolkata-700054, India
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Genome-based reconstruction of the protein import machinery in the secondary plastid of a chlorarachniophyte alga. EUKARYOTIC CELL 2012; 11:324-33. [PMID: 22267775 DOI: 10.1128/ec.05264-11] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Most plastid proteins are encoded by their nuclear genomes and need to be targeted across multiple envelope membranes. In vascular plants, the translocons at the outer and inner envelope membranes of chloroplasts (TOC and TIC, respectively) facilitate transport across the two plastid membranes. In contrast, several algal groups harbor more complex plastids, the so-called secondary plastids, which are surrounded by three or four membranes, but the plastid protein import machinery (in particular, how proteins cross the membrane corresponding to the secondary endosymbiont plasma membrane) remains unexplored in many of these algae. To reconstruct the putative protein import machinery of a secondary plastid, we used the chlorarachniophyte alga Bigelowiella natans, whose plastid is bounded by four membranes and still possesses a relict nucleus of a green algal endosymbiont (the nucleomorph) in the intermembrane space. We identified nine homologs of plant-like TOC/TIC components in the recently sequenced B. natans nuclear genome, adding to the two that remain in the nucleomorph genome (B. natans TOC75 [BnTOC75] and BnTIC20). All of these proteins were predicted to be localized to the plastid and might function in the inner two membranes. We also show that the homologs of a protein, Der1, that is known to mediate transport across the second membrane in the several lineages with secondary plastids of red algal origin is not associated with plastid protein targeting in B. natans. How plastid proteins cross this membrane remains a mystery, but it is clear that the protein transport machinery of chlorarachniophyte plastids differs from that of red algal secondary plastids.
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27
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Hsu SC, Belmonte MF, Harada JJ, Inoue K. Indispensable Roles of Plastids in Arabidopsis thaliana Embryogenesis. Curr Genomics 2011; 11:338-49. [PMID: 21286311 PMCID: PMC2944999 DOI: 10.2174/138920210791616716] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2010] [Revised: 05/18/2010] [Accepted: 05/25/2010] [Indexed: 11/22/2022] Open
Abstract
The plastid is an organelle vital to all photosynthetic and some non-photosynthetic eukaryotes. In the model plant Arabidopsis thaliana, a number of nuclear genes encoding plastid proteins have been found to be necessary for embryo development. However, the exact roles of plastids in this process remain largely unknown. Here we use publicly available datasets to obtain insights into the relevance of plastid activities to A. thaliana embryogenesis. By searching the SeedGenes database (http://www.seedgenes.org) and recent literature, we found that, of the 339 non-redundant genes required for proper embryo formation, 108 genes likely encode plastid-targeted proteins. Nineteen of these genes are necessary for development of preglobular embryos and/or their conversion to globular embryos, of which 13 genes encode proteins involved in non-photosynthetic metabolism. By contrast, among 38 genes which are dispensable for globular embryo formation but necessary for further development, only one codes for a protein involved in metabolism. Products of 21 of the 38 genes play roles in plastid gene expression and maintenance. Examination of RNA profiles of embryos at distinct growth stages obtained in laser-capture microdissection coupled with DNA microarray experiments revealed that most of the identified genes are expressed throughout embryo morphogenesis and maturation. These findings suggest that metabolic activities are required at preglobular and throughout all stages of embryo development, whereas plastid gene expression becomes necessary during and/or after the globular stage to sustain various activities of the organelle including photosynthetic electron transport.
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Affiliation(s)
- Shih-Chi Hsu
- Department of Plant Sciences, University of California, Davis, CA, USA
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28
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LTD is a protein required for sorting light-harvesting chlorophyll-binding proteins to the chloroplast SRP pathway. Nat Commun 2011; 2:277. [DOI: 10.1038/ncomms1278] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Accepted: 03/16/2011] [Indexed: 11/08/2022] Open
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29
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Chan CX, Gross J, Yoon HS, Bhattacharya D. Plastid origin and evolution: new models provide insights into old problems. PLANT PHYSIOLOGY 2011; 155:1552-60. [PMID: 21343425 PMCID: PMC3091110 DOI: 10.1104/pp.111.173500] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Accepted: 02/19/2011] [Indexed: 05/18/2023]
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30
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Andriotis VME, Pike MJ, Bunnewell S, Hills MJ, Smith AM. The plastidial glucose-6-phosphate/phosphate antiporter GPT1 is essential for morphogenesis in Arabidopsis embryos. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 64:128-39. [PMID: 20659277 DOI: 10.1111/j.1365-313x.2010.04313.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The glucose-6-phosphate/phosphate antiporter GPT1 is a major route of entry of carbon into non-photosynthetic plastids. To discover its importance in oilseeds, we used a seed-specific promoter to generate lines of Arabidopsis thaliana with reduced levels of GPT1 in developing embryos. Strong reductions resulted in seed abortion at the end of the globular stage of embryo development, when proplastids in normal embryos differentiate and acquire chlorophyll. Seed abortion was partly dependent on the light level during silique development. Embryos in seeds destined for abortion failed to undergo normal morphogenesis and were 'raspberry-like' in appearance. They had ultrastructural and biochemical defects including proliferation of peroxisomes and starch granules, and altered expression of genes involved in starch turnover and the oxidative pentose phosphate pathway. We propose that GPT1 is necessary for early embryo development because it catalyses import into plastids of glucose-6-phosphate as the substrate for NADPH generation via the oxidative pentose phosphate pathway. We suggest that low NADPH levels during plastid differentiation and chlorophyll synthesis may result in generation of reactive oxygen species and triggering of embryo cell death.
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Affiliation(s)
- Vasilios M E Andriotis
- Department of Metabolic Biology, John Innes Centre, Norwich Research Park, Norwich NR47UH, UK
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31
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Pang Y, Song WQ, Chen FY, Qin YM. A new cotton SDR family gene encodes a polypeptide possessing aldehyde reductase and 3-ketoacyl-CoA reductase activities. BIOCHEMISTRY (MOSCOW) 2010; 75:320-6. [PMID: 20370610 DOI: 10.1134/s0006297910030089] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To understand regulatory mechanisms of cotton fiber development, microarray analysis has been performed for upland cotton (Gossypium hirsutum). Based on this, a cDNA (GhKCR3) encoding a polypeptide belonging to short-chain alcohol dehydrogenase/reductase family was isolated and cloned. It contains an open reading frame of 987 bp encoding a polypeptide of 328 amino acid residues. Following its overexpression in bacterial cells, the purified recombinant protein specifically uses NADPH to reduce a variety of short-chain aldehydes. A fragment between Gly180 and Gly191 was found to be essential for its catalytic activity. Though the GhKCR3 gene shares low sequence similarities to the ortholog of Saccharomyces cerevisiae YBR159w that encodes 3-ketoacyl-CoA reductase (KCR) catalyzing the second step of fatty acid elongation, it was surprisingly able to complement the yeast ybr159wDelta mutant. Gas chromatography-mass spectrometry analysis showed that very long-chain fatty acids, especially C26:0, were produced in the ybr159wDelta mutant cells expressing GhKCR3. Applying palmitoyl-CoA and malonyl-CoA as substrates, GhKCR3 showed KCR activity in vitro. Quantitative real time-PCR analysis indicated GhKCR3 transcripts accumulated in rapidly elongating fibers, roots, and stems. Our results suggest that GhKCR3 is probably a novel KCR contributing to very long-chain fatty acid biosynthesis in plants.
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Affiliation(s)
- Yu Pang
- National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing, China
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32
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Schwenkert S, Soll J, Bölter B. Protein import into chloroplasts--how chaperones feature into the game. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1808:901-11. [PMID: 20682282 DOI: 10.1016/j.bbamem.2010.07.021] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2010] [Revised: 07/20/2010] [Accepted: 07/21/2010] [Indexed: 11/15/2022]
Abstract
Chloroplasts originated from an endosymbiotic event, in which an ancestral photosynthetic cyanobacterium was engulfed by a mitochondriate eukaryotic host cell. During evolution, the endosymbiont lost its autonomy by means of a massive transfer of genetic information from the prokaryotic genome to the host nucleus. Consequently, the development of protein import machineries became necessary for the relocation of proteins that are now nuclear-encoded and synthesized in the cytosol but destined for the chloroplast. Organelle biogenesis and maintenance requires a tight coordination of transcription, translation and protein import between the host cell and the organelle. This review focuses on the translocation complexes in the outer and inner envelope membrane with a special emphasis on the role of molecular chaperones. This article is part of a Special Issue entitled Protein translocation across or insertion into membranes.
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Affiliation(s)
- Serena Schwenkert
- Department Biologie I-Botanik, Ludwig-Maximilians-Universität, Großhadernerstr 2-4, D-82152 Planegg-Martinsried, Germany
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33
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Zhong R, Thompson J, Ottesen E, Lamppa GK. A forward genetic screen to explore chloroplast protein import in vivo identifies Moco sulfurase, pivotal for ABA and IAA biosynthesis and purine turnover. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 63:44-59. [PMID: 20374530 DOI: 10.1111/j.1365-313x.2010.04220.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
A genetic screen in Arabidopsis was developed to explore the regulation of chloroplast protein import in vivo using two independent reporters representing housekeeping and photosynthetic pre-proteins. We first used 5-enolpyruvylshikimate 3-phosphate synthase (EPSP synthase*), a key enzyme in the shikimic acid pathway, with a mutation that confers tolerance to the herbicide glyphosate. Because the EPSP synthase* pre-protein must be imported for its function, the loss of glyphosate tolerance provided an initial indication of an import deficiency. Second, the fate of GFP fused to a ferredoxin transit peptide (FD5-GFP) was determined. A class of altered chloroplast import (aci) mutants showed both glyphosate sensitivity and FD5-GFP mislocalized to nuclei. aci2-1 was selected for further study. Yellow fluorescent protein (YFP) fused to the transit peptide of EPSP synthase* or the small subunit of Rubisco was not imported into chloroplasts, but also localized to nuclei during protoplast transient expression. Isolated aci2-1 chloroplasts showed a 50% reduction in pre-protein import efficiency in an in vitro assay. Mutants did not grow photoautotrophically on media without sucrose and were small and dark green in soil. aci2-1 and two alleles code for Moco-sulfurase, which activates the aldehyde oxidases required for the biosynthesis of the plant hormones abscisic acid (ABA) and indole-acetic acid (IAA) and controls purine nucleotide (ATP and GTP) turnover and nitrogen recycling via xanthine dehydrogenase. These enzyme activities were not detected in aci2-1. ABA, IAA and/or purine turnover may play previously unrecognized roles in the regulation of chloroplast protein import in response to developmental, metabolic and environmental cues.
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Affiliation(s)
- Rong Zhong
- Department of Molecular Genetics and Cell Biology, The University of Chicago, 920 East 58th Street, Chicago, IL 60637, USA
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Stengel A, Benz JP, Soll J, Bölter B. Redox-regulation of protein import into chloroplasts and mitochondria: similarities and differences. PLANT SIGNALING & BEHAVIOR 2010; 5:105-9. [PMID: 20009579 PMCID: PMC2884109 DOI: 10.4161/psb.5.2.10525] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Redox signals play important roles in many developmental and metabolic processes, in particular in chloroplasts and mitochondria. Furthermore, redox reactions are crucial for protein folding via the formation of inter- or intramolecular disulfide bridges. Recently, redox signals were described to be additionally involved in regulation of protein import: in mitochondria, a disulfide relay system mediates retention of cystein-rich proteins in the intermembrane space by oxidizing them. Two essential proteins, the redox-activated receptor Mia40 and the sulfhydryl oxidase Erv1 participate in this pathway. In chloroplasts, it becomes apparent that protein import is affected by redox signals on both the outer and inner envelope: at the level of the Toc complex (translocon at the outer envelope of chloroplasts), the formation/reduction of disulfide bridges between the Toc components has a strong influence on import yield. Moreover, the stromal metabolic redox state seems to be sensed by the Tic complex (translocon at the inner envelope of chloroplasts) that is able to adjust translocation efficiency of a subgroup of redox-related preproteins accordingly. This review summarizes the current knowledge of these redox-regulatory pathways and focuses on similarities and differences between chloroplasts and mitochondria.
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Affiliation(s)
- Anna Stengel
- Munich Center for Integrated Protein Science CiPS(M-), Ludwig-Maximilians-Universität München, Munich, Germany
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35
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Protein import into chloroplasts: the Tic complex and its regulation. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1803:740-7. [PMID: 20100520 DOI: 10.1016/j.bbamcr.2010.01.015] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Revised: 01/11/2010] [Accepted: 01/13/2010] [Indexed: 11/24/2022]
Abstract
Chloroplasts like mitochondria were derived from an endosymbiontic event. Due to the massive gene transfer to the nucleus during endosymbiosis, only a limited number of chloroplastic proteins are still encoded for in the plastid genome. Most of the nuclear-encoded plastidic proteins are post-translationally translocated back to the chloroplast via the general import pathway through distinct outer and inner envelope membrane protein complexes, the Toc and Tic translocons (Translocon at the outer/inner envelope membrane of chloroplasts). Eight Tic subunits have been described so far, including two potential channel proteins (Tic110 and Tic20), the "motor complex" (Tic40 associated with the stromal chaperone Hsp93) and the "redox regulon" (Tic62, Tic55, and Tic32) involved in regulation of protein import via the metabolic redox status of the chloroplast. Regulation can additionally occur via thioredoxins (Tic110 and Tic55) or via the calcium/calmodulin network (Tic110 and Tic32). In this review we present the current knowledge about the Tic complex focusing on its regulation and addressing some still open questions.
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Abstract
Plastids are a heterogeneous family of organelles found ubiquitously in plants and algal cells. Most prominent are the chloroplasts, which carry out such essential processes as photosynthesis and the biosynthesis of fatty acids as well as of amino acids. As mitochondria, chloroplasts are derived from a single endosymbiotic event. They are believed to have evolved from an ancient cyanobacterium, which was engulfed by an early eukaryotic ancestor. During evolution the plastid genome has been greatly reduced and most of the genes have been transferred to the host nucleus. Consequently, more than 98% of all plastid proteins are translated on cytosolic ribosomes. They have to be posttranslationally targeted to and imported into the organelle. Targeting is assisted by cytosolic proteins which interact with proteins destined for plastids and thereby keep them in an import competent state. After reaching the target organelle, many proteins have to conquer the barrier of the chloroplast outer and inner envelope. This process is mediated by complex molecular machines in the outer (Toc complex) and inner (Tic complex) envelope of chloroplasts, respectively. Most proteins destined for the compartments inside the chloroplast contain a cleavable N-terminal transit peptide, whereas most of the outer envelope components insert into the membrane without such a targeting peptide.
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Affiliation(s)
- Penelope Strittmatter
- Department Biologie I-Botanik, Ludwig-Maximilians-Universität, Planegg-Martinsried and Munich Center for Integrated Protein Science, CiPSM, Ludwig-Maximilians- Universität, Munich, Germany
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37
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Abstract
Most proteins in chloroplasts are encoded by the nuclear genome and synthesized as precursors with N-terminal targeting signals called transit peptides. Novel machinery has evolved to specifically import these proteins from the cytosol into chloroplasts. This machinery consists of more than a dozen components located in and around the chloroplast envelope, including a pair of GTPase receptors, a beta-barrel-type channel across the outer membrane, and an AAA(+)-type motor in the stroma. How individual components assemble into functional subcomplexes and the sequential steps of the translocation process are being mapped out. An increasing number of noncanonical import pathways, including a pathway with initial transport through the endomembrane system, is being revealed. Multiple levels of control on protein transport into chloroplasts have evolved, including the development of two receptor subfamilies, one for photosynthetic proteins and one for housekeeping proteins. The functions or expression levels of some translocon components are further adjusted according to plastid type, developmental stage, and metabolic conditions.
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Affiliation(s)
- Hsou-min Li
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan.
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Benz J, Stengel A, Lintala M, Lee YH, Weber A, Philippar K, Gügel I, Kaieda S, Ikegami T, Mulo P, Soll J, Bölter B. Arabidopsis Tic62 and ferredoxin-NADP(H) oxidoreductase form light-regulated complexes that are integrated into the chloroplast redox poise. THE PLANT CELL 2009; 21:3965-83. [PMID: 20040542 PMCID: PMC2814497 DOI: 10.1105/tpc.109.069815] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2009] [Revised: 10/29/2009] [Accepted: 12/14/2009] [Indexed: 05/18/2023]
Abstract
Translocation of nuclear-encoded preproteins across the inner envelope of chloroplasts is catalyzed by the Tic translocon, consisting of Tic110, Tic40, Tic62, Tic55, Tic32, Tic20, and Tic22. Tic62 was proposed to act as a redox sensor of the complex because of its redox-dependent shuttling between envelope and stroma and its specific interaction with the photosynthetic protein ferredoxin-NADP(H) oxidoreductase (FNR). However, the nature of this close relationship so far remained enigmatic. A putative additional localization of Tic62 at the thylakoids mandated further studies examining how this feature might be involved in the respective redox sensing pathway and the interaction with its partner protein. Therefore, both the association with FNR and the physiological role of the third, thylakoid-bound pool of Tic62 were investigated in detail. Coexpression analysis indicates that Tic62 has similar expression patterns as genes involved in photosynthetic functions and protein turnover. At the thylakoids, Tic62 and FNR form high molecular weight complexes that are not involved in photosynthetic electron transfer but are dynamically regulated by light signals and the stromal pH. Structural analyses reveal that Tic62 binds to FNR in a novel binding mode for flavoproteins, with a major contribution from hydrophobic interactions. Moreover, in absence of Tic62, membrane binding and stability of FNR are drastically reduced. We conclude that Tic62 represents a major FNR interaction partner not only at the envelope and in the stroma, but also at the thylakoids of Arabidopsis thaliana and perhaps all flowering plants. Association with Tic62 stabilizes FNR and is involved in its dynamic and light-dependent membrane tethering.
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Affiliation(s)
- J.P. Benz
- Munich Center for Integrated Protein Science CiPS, Ludwig-Maximilians-Universität München, D-81377 Munich, Germany
- Department of Biology I, Botany, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany
| | - A. Stengel
- Munich Center for Integrated Protein Science CiPS, Ludwig-Maximilians-Universität München, D-81377 Munich, Germany
- Department of Biology I, Botany, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany
| | - M. Lintala
- Laboratory of Plant Physiology and Molecular Biology, Department of Biology, University of Turku, FIN-20014 Turku, Finland
| | - Y.-H. Lee
- Institute for Protein Research, Osaka University and CREST, Japan Science and Technology Agency, Suita, Osaka 565-0871, Japan
| | - A. Weber
- Institut für Biochemie der Pflanzen, Heinrich-Heine-Universität, 40225 Duesseldorf, Germany
| | - K. Philippar
- Munich Center for Integrated Protein Science CiPS, Ludwig-Maximilians-Universität München, D-81377 Munich, Germany
- Department of Biology I, Botany, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany
| | - I.L. Gügel
- Munich Center for Integrated Protein Science CiPS, Ludwig-Maximilians-Universität München, D-81377 Munich, Germany
- Department of Biology I, Botany, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany
| | - S. Kaieda
- Institute for Protein Research, Osaka University and CREST, Japan Science and Technology Agency, Suita, Osaka 565-0871, Japan
| | - T. Ikegami
- Institute for Protein Research, Osaka University and CREST, Japan Science and Technology Agency, Suita, Osaka 565-0871, Japan
| | - P. Mulo
- Laboratory of Plant Physiology and Molecular Biology, Department of Biology, University of Turku, FIN-20014 Turku, Finland
| | - J. Soll
- Munich Center for Integrated Protein Science CiPS, Ludwig-Maximilians-Universität München, D-81377 Munich, Germany
- Department of Biology I, Botany, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany
| | - B. Bölter
- Munich Center for Integrated Protein Science CiPS, Ludwig-Maximilians-Universität München, D-81377 Munich, Germany
- Department of Biology I, Botany, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany
- Address correspondence to
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Boij P, Patel R, Garcia C, Jarvis P, Aronsson H. In vivo studies on the roles of Tic55-related proteins in chloroplast protein import in Arabidopsis thaliana. MOLECULAR PLANT 2009; 2:1397-1409. [PMID: 19995737 DOI: 10.1093/mp/ssp079] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The Tic55 (Translocon at the inner envelope membrane of chloroplasts, 55 kDa) protein was identified in pea as a putative regulator, possibly linking chloroplast protein import to the redox state of the photosynthetic machinery. Two Tic55 homologs have been proposed to exist in Arabidopsis: atTic55-II and AtPTC52 (Protochlorophyllide-dependent Translocon Component, 52 kDa; has also been called atTic55-IV). Our phylogenetic analysis shows that atTic55-II is an ortholog of psTic55 from pea (Pisum sativum), and that AtPTC52 is a more distant homolog of the two. AtPTC52 was included in this study to rule out possible functional links between the proteins in Arabidopsis. No detectable mutant phenotypes were found in two independent T-DNA knockout mutant plant lines for each Arabidopsis protein, when compared with wild-type: visible appearance, chlorophyll content, photosynthetic performance, and chloroplast protein import, for example, were all normal. Both wild-type and tic55-II mutant chloroplasts exhibited deficient protein import when treated with diethylpyrocarbonate, indicating that Tic55 is not the sole target of this reagent in relation to protein import. Furthermore, ptc52 mutant chloroplasts were not defective with respect to pPORA import, which was previously reported to involve PTC52 in barley. Thus, we conclude that atTic55-II and AtPTC52 are not strictly required for functional protein import in Arabidopsis.
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Affiliation(s)
- Patrik Boij
- Department of Plant and Environmental Sciences, University of Gothenburg, Box 461, SE-405 30 Gothenburg, Sweden
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Stengel A, Benz JP, Buchanan BB, Soll J, Bölter B. Preprotein import into chloroplasts via the Toc and Tic complexes is regulated by redox signals in Pisum sativum. MOLECULAR PLANT 2009; 2:1181-97. [PMID: 19995724 DOI: 10.1093/mp/ssp043] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The import of nuclear-encoded preproteins is necessary to maintain chloroplast function. The recognition and transfer of most precursor proteins across the chloroplast envelopes are facilitated by two membrane-inserted protein complexes, the translocons of the chloroplast outer and inner envelope (Toc and Tic complexes, respectively). Several signals have been invoked to regulate the import of preproteins. In our study, we were interested in redox-based import regulation mediated by two signals: regulation based on thiols and on the metabolic NADP+/NADPH ratio. We sought to identify the proteins participating in the regulation of these transport pathways and to characterize the preprotein subgroups whose import is redox-dependent. Our results provide evidence that the formation and reduction of disulfide bridges in the Toc receptors and Toc translocation channel have a strong influence on import yield of all tested preproteins that depend on the Toc complex for translocation. Furthermore, the metabolic NADP+/NADPH ratio influences not only the composition of the Tic complex, but also the import efficiency of most, but not all, preproteins tested. Thus, several Tic subcomplexes appear to participate in the translocation of different preprotein subgroups, and the redox-active components of these complexes likely play a role in regulating transport.
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Affiliation(s)
- Anna Stengel
- Munich Center for Integrated Protein Science CiPSM, Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, D-81377 Munich, Germany
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Bussemer J, Vothknecht UC, Chigri F. Calcium regulation in endosymbiotic organelles of plants. PLANT SIGNALING & BEHAVIOR 2009; 4:805-8. [PMID: 19847100 PMCID: PMC2802815 DOI: 10.4161/psb.4.9.9234] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2009] [Accepted: 08/06/2009] [Indexed: 05/28/2023]
Abstract
In plant cells calcium-dependent signaling pathways are involved in a large array of biological processes in response to hormones, biotic/abiotic stress signals and a variety of developmental cues. This is generally achieved through binding of calcium to diverse calcium-sensing proteins, which subsequently control downstream events by activating or inhibiting biochemical reactions. Regulation by calcium is considered as a eukaryotic trait and has not been described for prokaryotes. Nevertheless, there is increasing evidence indicating that organelles of prokaryotic origin, such as chloroplasts and mitochondria, are integrated into the calcium-signaling network of the cell. An important transducer of calcium in these organelles appears to be calmodulin. In this review we want to give an overview over present data showing that endosymbiotic organelles harbour calcium-dependent biological processes with a focus on calmodulin-regulation.
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Kessler F, Schnell D. Chloroplast biogenesis: diversity and regulation of the protein import apparatus. Curr Opin Cell Biol 2009; 21:494-500. [DOI: 10.1016/j.ceb.2009.03.004] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2009] [Revised: 03/24/2009] [Accepted: 03/26/2009] [Indexed: 01/14/2023]
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Benz JP, Soll J, Bölter B. Protein transport in organelles: The composition, function and regulation of the Tic complex in chloroplast protein import. FEBS J 2009; 276:1166-76. [DOI: 10.1111/j.1742-4658.2009.06874.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Gross J, Bhattacharya D. Revaluating the evolution of the Toc and Tic protein translocons. TRENDS IN PLANT SCIENCE 2009; 14:13-20. [PMID: 19042148 DOI: 10.1016/j.tplants.2008.10.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2008] [Revised: 09/29/2008] [Accepted: 10/03/2008] [Indexed: 05/08/2023]
Abstract
The origin of the plastid from a cyanobacterial endosymbiont necessitated the establishment of specialized molecular machines (translocons) to facilitate the import of nuclear-encoded proteins into the organelle. To improve our understanding of the evolution of the translocons at the outer and inner envelope membrane of chloroplasts (Toc and Tic, respectively), we critically reassess the prevalent notion that their subunits have a function exclusive to protein import. We propose that many translocon components are multifunctional, conserving ancestral pre-endosymbiotic properties that predate their recruitment into the primitive translocon (putatively composed of subunits Toc34, Toc75 and Tic110 and associated chaperones). Multifunctionality seems to be a hallmark of the Tic complex, in which protein import is integrated with a broad array of plastid processes.
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Affiliation(s)
- Jeferson Gross
- University of Iowa, Department of Biology and the Roy J. Carver Center for Comparative Genomics, 446 Biology Building, Iowa City, IA 52242, USA
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45
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Aronsson H, Jarvis P. The Chloroplast Protein Import Apparatus, Its Components, and Their Roles. PLANT CELL MONOGRAPHS 2008. [DOI: 10.1007/978-3-540-68696-5_3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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The chloroplast protein translocation complexes of Chlamydomonas reinhardtii: a bioinformatic comparison of Toc and Tic components in plants, green algae and red algae. Genetics 2008; 179:95-112. [PMID: 18493043 DOI: 10.1534/genetics.107.085704] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The recently completed genome of Chlamydomonas reinhardtii was surveyed for components of the chloroplast protein translocation complexes. Putative components were identified using reciprocal BlastP searches with the protein sequences of Arabidopsis thaliana as queries. As a comparison, we also surveyed the new genomes of the bryophyte Physcomitrella patens, two prasinophyte green algae (Ostreococcus lucimarinus and Ostreococcus tauri), the red alga Cyanidioschizon merolae, and several cyanobacteria. Overall, we found that the components of the import pathway are remarkably well conserved, particularly among the Viridiplantae lineages. Specifically, C. reinhardtii contained almost all the components found in A. thaliana, with two exceptions. Missing from C. reinhardtii are the C-terminal ferredoxin-NADPH-reductase (FNR) binding domain of Tic62 and a full-length, TPR-bearing Toc64. Further, the N-terminal domain of C. reinhardtii Toc34 is highly acidic, whereas the analogous region in C. reinhardtii Toc159 is not. This reversal of the vascular plant model may explain the similarity of C. reinhardtii chloroplast transit peptides to mitochondrial-targeting peptides. Other findings from our genome survey include the absence of Tic22 in both Ostreococcus genomes; the presence of only one Toc75 homolog in C. merolae; and, finally, a distinctive propensity for gene duplication in P. patens.
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Abstract
Plastids are a diverse group of essential organelles in plants that include chloroplasts. The biogenesis and maintenance of these organelles relies on the import of thousands of nucleus-encoded proteins. The complexity of plastid structure has resulted in the evolution of at least four general import pathways that target proteins into and across the double membrane of the plastid envelope. Several of these pathways can be further divided into specialty pathways that mediate and regulate the import of specific classes of proteins. The co-ordination of import by these specialized pathways with changes in gene expression is critical for plastid and plant development. Moreover, protein import is acutely regulated in response to physiological and metabolic changes within the cell. In the present review we summarize the current knowledge of the mechanism of import via these pathways and highlight the regulatory mechanisms that integrate the plastid protein-trafficking pathways with the developmental and metabolic state of the plant.
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Abstract
Most chloroplast proteins are encoded in the nucleus and synthesized on free, cytosolic ribosomes in precursor form. Each precursor has an amino-terminal extension called a transit peptide, which directs the protein through a post-translational targeting pathway and is removed upon arrival inside the organelle. This 'protein import' process is mediated by the coordinate action of two multiprotein complexes, one in each of the envelope membranes: the TOC and TIC (Translocon at the Outer/ Inner envelope membrane of Chloroplasts) machines. Many components of these complexes have been identified biochemically in pea; these include transit peptide receptors, channel proteins, and molecular chaperones. Intriguingly, the Arabidopsis genome encodes multiple, homologous genes for receptor components of the TOC complex. Careful analysis indicated that the different receptor isoforms operate in different import pathways with distinct precursor recognition specificities. These 'substrate-specific' import pathways might play a role in the differentiation of different plastid types, and/or act to prevent deleterious competition effects between abundant and nonabundant precursors. Until recently, all proteins destined for internal chloroplast compartments were thought to possess a cleavable transit peptide, and to engage the TOC/TIC machinery. New studies using proteomics and other approaches have revealed that this is far from true. Remarkably, a significant number of chloroplast proteins are transported via a pathway that involves the endoplasmic reticulum and Golgi apparatus. Other recent reports have elucidated an intriguing array of protein targeting routes leading to the envelope membranes themselves.
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Affiliation(s)
- Paul Jarvis
- Department of Biology, University of Leicester, Leicester LE1 7RH, UK
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Chi W, Ma J, Zhang D, Guo J, Chen F, Lu C, Zhang L. The pentratricopeptide repeat protein DELAYED GREENING1 is involved in the regulation of early chloroplast development and chloroplast gene expression in Arabidopsis. PLANT PHYSIOLOGY 2008; 147:573-84. [PMID: 18400937 PMCID: PMC2409026 DOI: 10.1104/pp.108.116194] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2008] [Accepted: 04/01/2008] [Indexed: 05/18/2023]
Abstract
An Arabidopsis (Arabidopsis thaliana) mutant that exhibited a delayed greening phenotype (dg1) was isolated from a population of activation-tagged Arabidopsis lines. Young, inner leaves of dg1 mutants were initially very pale, but gradually greened and mature outer leaves, more than 3 weeks old, appeared similar to those of wild-type plants. Sequence and transcription analyses showed that DG1 encodes a chloroplast protein consisting of eight pentratricopeptide repeat domains and that its expression depends on both light and developmental status. In addition, analysis of the transcript profiles of chloroplast genes revealed that plastid-encoded polymerase-dependent transcript levels were markedly reduced, while nucleus-encoded polymerase-dependent transcript levels were increased, in dg1 mutants. Thus, DG1 is probably involved in the regulation of plastid-encoded polymerase-dependent chloroplast gene expression during early stages of chloroplast development.
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Affiliation(s)
- Wei Chi
- Photosynthesis Research Center, Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
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Stengel A, Benz P, Balsera M, Soll J, Bölter B. TIC62 redox-regulated translocon composition and dynamics. J Biol Chem 2008; 283:6656-67. [PMID: 18180301 DOI: 10.1074/jbc.m706719200] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The preprotein translocon at the inner envelope of chloroplasts (Tic complex) facilitates the import of nuclear-encoded preproteins into the organelle. Seven distinct subunits have been identified so far. For each of those, specific functions have been proposed based on structural prediction or experimental evidence. Three of those subunits possess modules that could act as redox-active regulatory components in the import process. To date, however, the mode of redox regulation of the import process remains enigmatic. To investigate how the chloroplast redox state influences translocon behavior and composition, we studied the Tic component and the putative redox sensor Tic62 in more detail. The experimental results provide evidence that Tic62 can act as a bona fide dehydrogenase in vitro, and that it changes its localization in the chloroplast dependent on the NADP+/NADPH ratio in the stroma. Moreover, the redox state influences the interactions of Tic62 with the translocon and the flavoenzyme ferredoxin-NADP+ oxidoreductase. Additionally, we give initial experimental insights into the Tic62 structure using circular dichroism measurements and demonstrate that the protein consists of two structurally different domains. Our results indicate that Tic62 possesses redox-dependent properties that would allow it to fulfill a role as redox sensor protein in the chloroplast.
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Affiliation(s)
- Anna Stengel
- Munich Center for Integrated Protein Science CiPS, Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, D-81377 Munich, Germany
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