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Teng X, Wang Y, Liu L, Yang H, Wu M, Chen X, Ren Y, Wang Y, Duan E, Dong H, Jiang L, Zhang Y, Zhang W, Chen R, Liu S, Liu X, Tian Y, Chen L, Wang Y, Wan J. Rice floury endosperm26 encoding a mitochondrial single-stranded DNA-binding protein is essential for RNA-splicing of mitochondrial genes and endosperm development. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2024; 346:112151. [PMID: 38848768 DOI: 10.1016/j.plantsci.2024.112151] [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: 12/18/2023] [Revised: 04/15/2024] [Accepted: 06/04/2024] [Indexed: 06/09/2024]
Abstract
Endosperm, the major storage organ in cereal grains, determines the grain yield and quality. Mitochondria provide the energy for dry matter accumulation, in the endosperm development. Although mitochondrial single-stranded DNA-binding proteins (mtSSBs) play a canonical role in the maintenance of single-stranded mitochondrial DNA, their molecular functions in RNA processing and endosperm development remain obscure. Here, we report a defective rice endosperm mutant, floury endosperm26 (flo26), which develops abnormal starch grains in the endosperm. Map-based cloning and complementation experiments showed that FLO26 allele encodes a mitochondrial single-stranded DNA-binding protein, named as mtSSB1.1. Loss of function of mtSSB1.1 affects the transcriptional level of many mitochondrially-encoded genes and RNA splicing of nad1, a core component of respiratory chain complex I in mitochondria. As a result, dysfunctional mature nad1 led to dramatically decreased complex I activity, thereby reducing ATP production. Our results reveal that mtSSB1.1 plays an important role in the maintenance of mitochondrial function and endosperm development by stabilizing the splicing of mitochondrial RNA in rice.
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Affiliation(s)
- Xuan Teng
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China; Zhongshan Biological Breeding Laboratory, No.50 Zhongling Street, Nanjing 210014, China
| | - Yongfei Wang
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China
| | - Linglong Liu
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China; Zhongshan Biological Breeding Laboratory, No.50 Zhongling Street, Nanjing 210014, China
| | - Hang Yang
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China
| | - Mingming Wu
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China
| | - Xiaoli Chen
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China
| | - Yulong Ren
- State Key Laboratory of Crop Gene Resources and Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Yunlong Wang
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China; Zhongshan Biological Breeding Laboratory, No.50 Zhongling Street, Nanjing 210014, China
| | - Erchao Duan
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China; Zhongshan Biological Breeding Laboratory, No.50 Zhongling Street, Nanjing 210014, China
| | - Hui Dong
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China; Zhongshan Biological Breeding Laboratory, No.50 Zhongling Street, Nanjing 210014, China
| | - Ling Jiang
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China; Zhongshan Biological Breeding Laboratory, No.50 Zhongling Street, Nanjing 210014, China
| | - Yuanyan Zhang
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China
| | - Wenwei Zhang
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China; Zhongshan Biological Breeding Laboratory, No.50 Zhongling Street, Nanjing 210014, China
| | - Rongbo Chen
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China
| | - Shijia Liu
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China; Zhongshan Biological Breeding Laboratory, No.50 Zhongling Street, Nanjing 210014, China
| | - Xi Liu
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China; Zhongshan Biological Breeding Laboratory, No.50 Zhongling Street, Nanjing 210014, China
| | - Yunlu Tian
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China; Zhongshan Biological Breeding Laboratory, No.50 Zhongling Street, Nanjing 210014, China
| | - Liangming Chen
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China; Zhongshan Biological Breeding Laboratory, No.50 Zhongling Street, Nanjing 210014, China
| | - Yihua Wang
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China; Zhongshan Biological Breeding Laboratory, No.50 Zhongling Street, Nanjing 210014, China.
| | - Jianmin Wan
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China; State Key Laboratory of Crop Gene Resources and Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China; Zhongshan Biological Breeding Laboratory, No.50 Zhongling Street, Nanjing 210014, China.
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Waneka G, Broz AK, Wold-McGimsey F, Zou Y, Wu Z, Sloan DB. Disruption of recombination machinery alters the mutational landscape in plant organellar genomes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.03.597120. [PMID: 38895361 PMCID: PMC11185577 DOI: 10.1101/2024.06.03.597120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Land plant organellar genomes have extremely low rates of point mutation yet also experience high rates of recombination and genome instability. Characterizing the molecular machinery responsible for these patterns is critical for understanding the evolution of these genomes. While much progress has been made towards understanding recombination activity in land plant organellar genomes, the relationship between recombination pathways and point mutation rates remains uncertain. The organellar targeted mutS homolog MSH1 has previously been shown to suppress point mutations as well as non-allelic recombination between short repeats in Arabidopsis thaliana. We therefore implemented high-fidelity Duplex Sequencing to test if other genes that function in recombination and maintenance of genome stability also affect point mutation rates. We found small to moderate increases in the frequency of single nucleotide variants (SNVs) and indels in mitochondrial and/or plastid genomes of A. thaliana mutant lines lacking radA, recA1, or recA3. In contrast, osb2 and why2 mutants did not exhibit an increase in point mutations compared to wild type (WT) controls. In addition, we analyzed the distribution of SNVs in previously generated Duplex Sequencing data from A. thaliana organellar genomes and found unexpected strand asymmetries and large effects of flanking nucleotides on mutation rates in WT plants and msh1 mutants. Finally, using long-read Oxford Nanopore sequencing, we characterized structural variants in organellar genomes of the mutant lines and show that different short repeat sequences become recombinationally active in different mutant backgrounds. Together, these complementary sequencing approaches shed light on how recombination may impact the extraordinarily low point mutation rates in plant organellar genomes.
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Affiliation(s)
- Gus Waneka
- Department of Biology, Colorado State University, Fort Collins, Colorado, USA
| | - Amanda K Broz
- Department of Biology, Colorado State University, Fort Collins, Colorado, USA
| | | | - Yi Zou
- Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, Guangdong 518120, China
| | - Zhiqiang Wu
- Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, Guangdong 518120, China
| | - Daniel B Sloan
- Department of Biology, Colorado State University, Fort Collins, Colorado, USA
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Gong J, Yang J, Lai Y, Pan T, She W. A High-Quality Assembly and Comparative Analysis of the Mitogenome of Actinidia macrosperma. Genes (Basel) 2024; 15:514. [PMID: 38674448 PMCID: PMC11049864 DOI: 10.3390/genes15040514] [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: 01/30/2024] [Revised: 04/15/2024] [Accepted: 04/15/2024] [Indexed: 04/28/2024] Open
Abstract
The mitochondrial genome (mitogenome) of Actinidia macrosperma, a traditional medicinal plant within the Actinidia genus, remains relatively understudied. This study aimed to sequence the mitogenome of A. macrosperma, determining its assembly, informational content, and developmental expression. The results revealed that the mitogenome of A. macrosperma is circular, spanning 752,501 bp with a GC content of 46.16%. It comprises 63 unique genes, including 39 protein-coding genes (PCGs), 23 tRNA genes, and three rRNA genes. Moreover, the mitogenome was found to contain 63 SSRs, predominantly mono-nucleotides, as well as 25 tandem repeats and 650 pairs of dispersed repeats, each with lengths equal to or greater than 60, mainly comprising forward repeats and palindromic repeats. Moreover, 53 homologous fragments were identified between the mitogenome and chloroplast genome (cp-genome), with the longest segment measuring 4296 bp. This study represents the initial report on the mitogenome of the A. macrosperma, providing crucial genetic materials for phylogenetic research within the Actinidia genus and promoting the exploitation of species genetic resources.
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Affiliation(s)
- Jiangmei Gong
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (J.G.); (Y.L.); (T.P.)
- Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Jun Yang
- College of Food and Bioengineering, Bengbu University, Bengbu 233030, China;
| | - Yan Lai
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (J.G.); (Y.L.); (T.P.)
- Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Tengfei Pan
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (J.G.); (Y.L.); (T.P.)
- Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Wenqin She
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (J.G.); (Y.L.); (T.P.)
- Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China
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4
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Peralta-Castro A, Cordoba-Andrade F, Díaz-Quezada C, Sotelo-Mundo R, Winkler R, Brieba LG. The plant organellar primase-helicase directs template recognition and primosome assembly via its zinc finger domain. BMC PLANT BIOLOGY 2023; 23:467. [PMID: 37803262 PMCID: PMC10557236 DOI: 10.1186/s12870-023-04477-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 09/19/2023] [Indexed: 10/08/2023]
Abstract
BACKGROUND The mechanisms and regulation for DNA replication in plant organelles are largely unknown, as few proteins involved in replisome assembly have been biochemically studied. A primase-helicase dubbed Twinkle (T7 gp4-like protein with intramitochondrial nucleoid localization) unwinds double-stranded DNA in metazoan mitochondria and plant organelles. Twinkle in plants is a bifunctional enzyme with an active primase module. This contrast with animal Twinkle in which the primase module is inactive. The organellar primase-helicase of Arabidopsis thaliana (AtTwinkle) harbors a primase module (AtPrimase) that consists of an RNA polymerase domain (RPD) and a Zn + + finger domain (ZFD). RESULTS Herein, we investigate the mechanisms by which AtTwinkle recognizes its templating sequence and how primer synthesis and coupling to the organellar DNA polymerases occurs. Biochemical data show that the ZFD of the AtPrimase module is responsible for template recognition, and this recognition is achieved by residues N163, R166, and K168. The role of the ZFD in template recognition was also corroborated by swapping the RPDs of bacteriophage T7 primase and AtPrimase with their respective ZFDs. A chimeric primase harboring the ZFD of T7 primase and the RPD of AtPrimase synthesizes ribonucleotides from the T7 primase recognition sequence and conversely, a chimeric primase harboring the ZFD of AtPrimase and the RPD of T7 primase synthesizes ribonucleotides from the AtPrimase recognition sequence. A chimera harboring the RPDs of bacteriophage T7 and the ZBD of AtTwinkle efficiently synthesizes primers for the plant organellar DNA polymerase. CONCLUSIONS We conclude that the ZFD is responsible for recognizing a single-stranded sequence and for primer hand-off into the organellar DNA polymerases active site. The primase activity of plant Twinkle is consistent with phylogeny-based reconstructions that concluded that Twinkle´s last eukaryotic common ancestor (LECA) was an enzyme with primase and helicase activities. In plants, the primase domain is active, whereas the primase activity was lost in metazoans. Our data supports the notion that AtTwinkle synthesizes primers at the lagging-strand of the organellar replication fork.
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Affiliation(s)
- Antolin Peralta-Castro
- Langebio-Cinvestav Sede Irapuato, Km. 9.6 Libramiento Norte Carretera. Irapuato-León, 36821, Irapuato Guanajuato, Mexico
| | - Francisco Cordoba-Andrade
- Langebio-Cinvestav Sede Irapuato, Km. 9.6 Libramiento Norte Carretera. Irapuato-León, 36821, Irapuato Guanajuato, Mexico
| | - Corina Díaz-Quezada
- Langebio-Cinvestav Sede Irapuato, Km. 9.6 Libramiento Norte Carretera. Irapuato-León, 36821, Irapuato Guanajuato, Mexico
| | - Rogerio Sotelo-Mundo
- Laboratorio de Estructura Biomolecular, Centro de Investigación en Alimentación y Desarrollo, A.C. Carretera Gustavo Enrique Astiazarán Rosas Núm. 46, Ejido a La Victoria, 83304, Hermosillo, Sonora, Mexico
| | - Robert Winkler
- Langebio-Cinvestav Sede Irapuato, Km. 9.6 Libramiento Norte Carretera. Irapuato-León, 36821, Irapuato Guanajuato, Mexico
| | - Luis G Brieba
- Langebio-Cinvestav Sede Irapuato, Km. 9.6 Libramiento Norte Carretera. Irapuato-León, 36821, Irapuato Guanajuato, Mexico.
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5
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Lee Y, Cho CH, Noh C, Yang JH, Park SI, Lee YM, West JA, Bhattacharya D, Jo K, Yoon HS. Origin of minicircular mitochondrial genomes in red algae. Nat Commun 2023; 14:3363. [PMID: 37291154 PMCID: PMC10250338 DOI: 10.1038/s41467-023-39084-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 05/30/2023] [Indexed: 06/10/2023] Open
Abstract
Eukaryotic organelle genomes are generally of conserved size and gene content within phylogenetic groups. However, significant variation in genome structure may occur. Here, we report that the Stylonematophyceae red algae contain multipartite circular mitochondrial genomes (i.e., minicircles) which encode one or two genes bounded by a specific cassette and a conserved constant region. These minicircles are visualized using fluorescence microscope and scanning electron microscope, proving the circularity. Mitochondrial gene sets are reduced in these highly divergent mitogenomes. Newly generated chromosome-level nuclear genome assembly of Rhodosorus marinus reveals that most mitochondrial ribosomal subunit genes are transferred to the nuclear genome. Hetero-concatemers that resulted from recombination between minicircles and unique gene inventory that is responsible for mitochondrial genome stability may explain how the transition from typical mitochondrial genome to minicircles occurs. Our results offer inspiration on minicircular organelle genome formation and highlight an extreme case of mitochondrial gene inventory reduction.
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Affiliation(s)
- Yongsung Lee
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419, Korea
| | - Chung Hyun Cho
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419, Korea
| | - Chanyoung Noh
- Department of Chemistry, Sogang University, Seoul, 04107, Korea
| | - Ji Hyun Yang
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419, Korea
| | - Seung In Park
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419, Korea
| | - Yu Min Lee
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419, Korea
| | - John A West
- School of Biosciences 2, University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Debashish Bhattacharya
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, 08901, USA
| | - Kyubong Jo
- Department of Chemistry, Sogang University, Seoul, 04107, Korea.
| | - Hwan Su Yoon
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419, Korea.
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Zhang X, Shan Y, Li J, Qin Q, Yu J, Deng H. Assembly of the Complete Mitochondrial Genome of Pereskia aculeata Revealed That Two Pairs of Repetitive Elements Mediated the Recombination of the Genome. Int J Mol Sci 2023; 24:ijms24098366. [PMID: 37176072 PMCID: PMC10179450 DOI: 10.3390/ijms24098366] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 05/01/2023] [Accepted: 05/03/2023] [Indexed: 05/15/2023] Open
Abstract
Pereskia aculeata is a potential new crop species that has both food and medicinal (antinociceptive activity) properties. However, comprehensive genomic research on P. aculeata is still lacking, particularly concerning its organelle genome. In this study, P. aculeata was studied to sequence the mitochondrial genome (mitogenome) and to ascertain the assembly, informational content, and developmental expression of the mitogenome. The findings revealed that the mitogenome of P. aculeata is circular and measures 515,187 bp in length with a GC content of 44.05%. It contains 52 unique genes, including 33 protein-coding genes, 19 tRNA genes, and three rRNA genes. Additionally, the mitogenome analysis identified 165 SSRs, primarily consisting of tetra-nucleotides, and 421 pairs of dispersed repeats with lengths greater than or equal to 30, which were mainly forward repeats. Based on long reads and PCR experiments, we confirmed that two pairs of long-fragment repetitive elements were highly involved with the mitogenome recombination process. Furthermore, there were 38 homologous fragments detected between the mitogenome and chloroplast genome, and the longest fragment was 3962 bp. This is the first report on the mitogenome in the family Cactaceae. The decoding of the mitogenome of P. aculeata will provide important genetic materials for phylogenetic studies of Cactaceae and promote the utilization of species germplasm resources.
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Affiliation(s)
- Xue Zhang
- College of Horticulture and Landscape Architecture, Southwest University, Chongqing 400716, China
| | - Yuanyu Shan
- College of Horticulture and Landscape Architecture, Southwest University, Chongqing 400716, China
| | - Jingling Li
- College of Horticulture and Landscape Architecture, Southwest University, Chongqing 400716, China
| | - Qiulin Qin
- College of Horticulture and Landscape Architecture, Southwest University, Chongqing 400716, China
| | - Jie Yu
- College of Horticulture and Landscape Architecture, Southwest University, Chongqing 400716, China
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River, Ministry of Education, Southwest University, Chongqing 400715, China
| | - Hongping Deng
- Center for Biodiversity Conservation and Utilization, School of Life Sciences, Southwest University, Chongqing 400715, China
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7
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Tripathi D, Oldenburg DJ, Bendich AJ. Oxidative and Glycation Damage to Mitochondrial DNA and Plastid DNA during Plant Development. Antioxidants (Basel) 2023; 12:antiox12040891. [PMID: 37107266 PMCID: PMC10135910 DOI: 10.3390/antiox12040891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 03/31/2023] [Accepted: 04/04/2023] [Indexed: 04/08/2023] Open
Abstract
Oxidative damage to plant proteins, lipids, and DNA caused by reactive oxygen species (ROS) has long been studied. The damaging effects of reactive carbonyl groups (glycation damage) to plant proteins and lipids have also been extensively studied, but only recently has glycation damage to the DNA in plant mitochondria and plastids been reported. Here, we review data on organellar DNA maintenance after damage from ROS and glycation. Our focus is maize, where tissues representing the entire range of leaf development are readily obtained, from slow-growing cells in the basal meristem, containing immature organelles with pristine DNA, to fast-growing leaf cells, containing mature organelles with highly-fragmented DNA. The relative contributions to DNA damage from oxidation and glycation are not known. However, the changing patterns of damage and damage-defense during leaf development indicate tight coordination of responses to oxidation and glycation events. Future efforts should be directed at the mechanism by which this coordination is achieved.
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Affiliation(s)
- Diwaker Tripathi
- Department of Biology, University of Washington, Seattle, WA 98195, USA
| | | | - Arnold J. Bendich
- Department of Biology, University of Washington, Seattle, WA 98195, USA
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8
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Taylor RE, West CE, Foyer CH. WHIRLY protein functions in plants. Food Energy Secur 2023; 12:e379. [PMID: 38440693 PMCID: PMC10909546 DOI: 10.1002/fes3.379] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Revised: 02/22/2022] [Accepted: 03/04/2022] [Indexed: 03/06/2024] Open
Abstract
Environmental stresses pose a significant threat to food security. Understanding the function of proteins that regulate plant responses to biotic and abiotic stresses is therefore pivotal in developing strategies for crop improvement. The WHIRLY (WHY) family of DNA-binding proteins are important in this regard because they fulfil a portfolio of important functions in organelles and nuclei. The WHY1 and WHY2 proteins function as transcription factors in the nucleus regulating phytohormone synthesis and associated growth and stress responses, as well as fulfilling crucial roles in DNA and RNA metabolism in plastids and mitochondria. WHY1, WHY2 (and WHY3 proteins in Arabidopsis) maintain organelle genome stability and serve as auxiliary factors for homologous recombination and double-strand break repair. Our understanding of WHY protein functions has greatly increased in recent years, as has our knowledge of the flexibility of their localization and overlap of functions but there is no review of the topic in the literature. Our aim in this review was therefore to provide a comprehensive overview of the topic, discussing WHY protein functions in nuclei and organelles and highlighting roles in plant development and stress responses. In particular, we consider areas of uncertainty such as the flexible localization of WHY proteins in terms of retrograde signalling connecting mitochondria, plastids, and the nucleus. Moreover, we identify WHY proteins as important targets in plant breeding programmes designed to increase stress tolerance and the sustainability of crop yield in a changing climate.
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Affiliation(s)
- Rachel E. Taylor
- Faculty of Biological SciencesThe Centre for Plant SciencesUniversity of LeedsLeedsUK
| | - Christopher E. West
- Faculty of Biological SciencesThe Centre for Plant SciencesUniversity of LeedsLeedsUK
| | - Christine H. Foyer
- School of BiosciencesCollege of Life and Environmental SciencesUniversity of BirminghamBirminghamUK
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9
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Qian J, Zheng M, Wang L, Song Y, Yan J, Hsu YF. Arabidopsis mitochondrial single-stranded DNA-binding proteins SSB1 and SSB2 are essential regulators of mtDNA replication and homologous recombination. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2022; 64:1952-1965. [PMID: 35925893 DOI: 10.1111/jipb.13338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 08/04/2022] [Indexed: 06/15/2023]
Abstract
Faithful DNA replication is one of the most essential processes in almost all living organisms. However, the proteins responsible for organellar DNA replication are still largely unknown in plants. Here, we show that the two mitochondrion-targeted single-stranded DNA-binding (SSB) proteins SSB1 and SSB2 directly interact with each other and act as key factors for mitochondrial DNA (mtDNA) maintenance, as their single or double loss-of-function mutants exhibit severe germination delay and growth retardation. The mtDNA levels in mutants lacking SSB1 and/or SSB2 function were two- to four-fold higher than in the wild-type (WT), revealing a negative role for SSB1/2 in regulating mtDNA replication. Genetic analysis indicated that SSB1 functions upstream of mitochondrial DNA POLYMERASE IA (POLIA) or POLIB in mtDNA replication, as mutation in either gene restored the high mtDNA copy number of the ssb1-1 mutant back to WT levels. In addition, SSB1 and SSB2 also participate in mitochondrial genome maintenance by influencing mtDNA homologous recombination (HR). Additional genetic analysis suggested that SSB1 functions upstream of ORGANELLAR SINGLE-STRANDED DNA-BINDING PROTEIN1 (OSB1) during mtDNA replication, while SSB1 may act downstream of OSB1 and MUTS HOMOLOG1 for mtDNA HR. Overall, our results yield new insights into the roles of the plant mitochondrion-targeted SSB proteins and OSB1 in maintaining mtDNA stability via affecting DNA replication and DNA HR.
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Affiliation(s)
- Jie Qian
- School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Min Zheng
- School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Lingyu Wang
- School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Yu Song
- School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Jiawen Yan
- School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Yi-Feng Hsu
- School of Life Sciences, Southwest University, Chongqing, 400715, China
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10
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Shrestha HK, Fichman Y, Engle NL, Tschaplinski TJ, Mittler R, Dixon RA, Hettich RL, Barros J, Abraham PE. Multi-omic characterization of bifunctional peroxidase 4-coumarate 3-hydroxylase knockdown in Brachypodium distachyon provides insights into lignin modification-associated pleiotropic effects. FRONTIERS IN PLANT SCIENCE 2022; 13:908649. [PMID: 36247563 PMCID: PMC9554711 DOI: 10.3389/fpls.2022.908649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 09/09/2022] [Indexed: 06/16/2023]
Abstract
A bifunctional peroxidase enzyme, 4-coumarate 3-hydroxylase (C3H/APX), provides a parallel route to the shikimate shunt pathway for the conversion of 4-coumarate to caffeate in the early steps of lignin biosynthesis. Knockdown of C3H/APX (C3H/APX-KD) expression has been shown to reduce the lignin content in Brachypodium distachyon. However, like many other lignin-modified plants, C3H/APX-KDs show unpredictable pleiotropic phenotypes, including stunted growth, delayed senescence, and reduced seed yield. A system-wide level understanding of altered biological processes in lignin-modified plants can help pinpoint the lignin-modification associated growth defects to benefit future studies aiming to negate the yield penalty. Here, a multi-omic approach was used to characterize molecular changes resulting from C3H/APX-KD associated lignin modification and negative growth phenotype in Brachypodium distachyon. Our findings demonstrate that C3H/APX knockdown in Brachypodium stems substantially alters the abundance of enzymes implicated in the phenylpropanoid biosynthetic pathway and disrupt cellular redox homeostasis. Moreover, it elicits plant defense responses associated with intracellular kinases and phytohormone-based signaling to facilitate growth-defense trade-offs. A deeper understanding along with potential targets to mitigate the pleiotropic phenotypes identified in this study could aid to increase the economic feasibility of lignocellulosic biofuel production.
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Affiliation(s)
- Him K. Shrestha
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Genome Science and Technology, University of Tennessee-Knoxville, Knoxville, TN, United States
| | - Yosef Fichman
- Division of Plant Sciences and Interdisciplinary Plant Group, University of Missouri, Columbia, MO, United States
| | - Nancy L. Engle
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | | | - Ron Mittler
- Division of Plant Sciences and Interdisciplinary Plant Group, University of Missouri, Columbia, MO, United States
| | - Richard A. Dixon
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, Denton, TX, United States
| | - Robert L. Hettich
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Jaime Barros
- Division of Plant Sciences and Interdisciplinary Plant Group, University of Missouri, Columbia, MO, United States
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, Denton, TX, United States
| | - Paul E. Abraham
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
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11
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Zhang M, Shen J, Wu Y, Zhang X, Zhao Z, Wang J, Cheng T, Zhang Q, Pan H. Comparative transcriptome analysis identified ChlH and POLGAMMA2 in regulating yellow-leaf coloration in Forsythia. FRONTIERS IN PLANT SCIENCE 2022; 13:1009575. [PMID: 36160960 PMCID: PMC9501713 DOI: 10.3389/fpls.2022.1009575] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 08/24/2022] [Indexed: 05/24/2023]
Abstract
Leaf color is one of the most important features for plants used for landscape and ornamental purposes. However, the regulatory mechanism of yellow leaf coloration still remains elusive in many plant species. To understand the complex genetic mechanism of yellow-leaf Forsythia, we first compared the pigment content and leaf anatomical structure of yellow-leaf and green-leaf accessions derived from a hybrid population. The physiological and cytological analyses demonstrated that yellow-leaf progenies were chlorophyll deficient with defected chloroplast structure. With comparative transcriptome analysis, we identified a number of candidate genes differentially expressed between yellow-leaf and green-leaf Forsythia plants. Among these genes, we further screened out two candidates, ChlH (magnesium chelatase Subunit H) and POLGAMMA2 (POLYMERASE GAMMA 2), with consistent relative-expression pattern between different colored plants. To verify the gene function, we performed virus-induced gene silencing assays and observed yellow-leaf phenotype with total chlorophyll content reduced by approximately 66 and 83% in ChlH-silenced and POLGAMMA2-silenced plants, respectively. We also observed defected chloroplast structure in both ChlH-silenced and POLGAMMA2-silenced Forsythia. Transient over-expression of ChlH and POLGAMMA2 led to increased chlorophyll content and restored thylakoid architecture in yellow-leaf Forsythia. With transcriptome sequencing, we detected a number of genes related to chlorophyll biosynthesis and chloroplast development that were responsive to the silencing of ChlH and POLGAMMA2. To summarize, ChlH and POLGAMMA2 are two key genes that possibly related to yellow-leaf coloration in Forsythia through modulating chlorophyll synthesis and chloroplast ultrastructure. Our study provided insights into the molecular aspects of yellow-leaf Forsythia and expanded the knowledge of foliage color regulation in woody ornamental plants.
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Affiliation(s)
- Man Zhang
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, College of Landscape Architecture, Beijing Forestry University, Beijing, China
| | - Jianshuang Shen
- Department of Landscape Architecture, Jiyang College, Zhejiang A&F University, Zhuji, China
| | - Yutong Wu
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, College of Landscape Architecture, Beijing Forestry University, Beijing, China
| | - Xiaolu Zhang
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, College of Landscape Architecture, Beijing Forestry University, Beijing, China
| | - Zhengtian Zhao
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, College of Landscape Architecture, Beijing Forestry University, Beijing, China
| | - Jia Wang
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, College of Landscape Architecture, Beijing Forestry University, Beijing, China
| | - Tangren Cheng
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, College of Landscape Architecture, Beijing Forestry University, Beijing, China
| | - Qixiang Zhang
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, College of Landscape Architecture, Beijing Forestry University, Beijing, China
| | - Huitang Pan
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, College of Landscape Architecture, Beijing Forestry University, Beijing, China
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12
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Mattiello L, Rütgers M, Sua-Rojas MF, Tavares R, Soares JS, Begcy K, Menossi M. Molecular and Computational Strategies to Increase the Efficiency of CRISPR-Based Techniques. FRONTIERS IN PLANT SCIENCE 2022; 13:868027. [PMID: 35712599 PMCID: PMC9194676 DOI: 10.3389/fpls.2022.868027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 04/27/2022] [Indexed: 06/15/2023]
Abstract
The prokaryote-derived Clustered Regularly Interspaced Palindromic Repeats (CRISPR)/Cas mediated gene editing tools have revolutionized our ability to precisely manipulate specific genome sequences in plants and animals. The simplicity, precision, affordability, and robustness of this technology have allowed a myriad of genomes from a diverse group of plant species to be successfully edited. Even though CRISPR/Cas, base editing, and prime editing technologies have been rapidly adopted and implemented in plants, their editing efficiency rate and specificity varies greatly. In this review, we provide a critical overview of the recent advances in CRISPR/Cas9-derived technologies and their implications on enhancing editing efficiency. We highlight the major efforts of engineering Cas9, Cas12a, Cas12b, and Cas12f proteins aiming to improve their efficiencies. We also provide a perspective on the global future of agriculturally based products using DNA-free CRISPR/Cas techniques. The improvement of CRISPR-based technologies efficiency will enable the implementation of genome editing tools in a variety of crop plants, as well as accelerate progress in basic research and molecular breeding.
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Affiliation(s)
- Lucia Mattiello
- Department of Genetics, Evolution, Microbiology and Immunology, Institute of Biology, State University of Campinas (UNICAMP), Campinas, Brazil
| | - Mark Rütgers
- Department of Genetics, Evolution, Microbiology and Immunology, Institute of Biology, State University of Campinas (UNICAMP), Campinas, Brazil
| | - Maria Fernanda Sua-Rojas
- Department of Genetics, Evolution, Microbiology and Immunology, Institute of Biology, State University of Campinas (UNICAMP), Campinas, Brazil
| | - Rafael Tavares
- Cell and Developmental Biology, John Innes Centre, Norwich, United Kingdom
| | - José Sérgio Soares
- Department of Genetics, Evolution, Microbiology and Immunology, Institute of Biology, State University of Campinas (UNICAMP), Campinas, Brazil
| | - Kevin Begcy
- Environmental Horticulture Department, University of Florida, Gainesville, FL, United States
| | - Marcelo Menossi
- Department of Genetics, Evolution, Microbiology and Immunology, Institute of Biology, State University of Campinas (UNICAMP), Campinas, Brazil
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13
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Wu M, Dong Y, Zhang Q, Li S, Chang L, Loiacono FV, Ruf S, Zhang J, Bock R. Efficient control of western flower thrips by plastid-mediated RNA interference. Proc Natl Acad Sci U S A 2022; 119:e2120081119. [PMID: 35380896 PMCID: PMC9169809 DOI: 10.1073/pnas.2120081119] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 03/07/2022] [Indexed: 11/24/2022] Open
Abstract
Plastid-mediated RNA interference (PM-RNAi) has emerged as a promising strategy for pest control. Expression from the plastid genome of stable double-stranded RNAs (dsRNAs) targeted against essential insect genes can effectively control some herbivorous beetles, but little is known about the efficacy of the transplastomic approach in other groups of pest insects, especially nonchewing insects that do not consume large amounts of leaf material. Here we have investigated the susceptibility of the western flower thrip (WFT, Frankliniella occidentalis), a notorious pest in greenhouses and open fields, to PM-RNAi. We show that WFTs ingest chloroplasts and take up plastid-expressed dsRNAs. We generated a series of transplastomic tobacco plants expressing dsRNAs and hairpin RNAs (hpRNAs) targeted against four essential WFT genes. Unexpectedly, we discovered plastid genome instability in transplastomic plants expressing hpRNAs, suggesting that dsRNA cassettes are preferable over hpRNA cassettes when designing PM-RNAi strategies. Feeding studies revealed that, unlike nuclear transgenic plants, transplastomic plants induced a potent RNAi response in WFTs, causing efficient suppression of the targeted genes and high insect mortality. Our study extends the application range of PM-RNAi technology to an important group of nonchewing insects, reveals design principles for the construction of dsRNA-expressing transplastomic plants, and provides an efficient approach to control one of the toughest insect pests in agriculture and horticulture.
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Affiliation(s)
- Mengting Wu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan 430062, China
- Max Planck Institut für Molekulare Pflanzenphysiologie, Department III, D-14476 Potsdam-Golm, Germany
| | - Yi Dong
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Qi Zhang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Shengchun Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Ling Chang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan 430062, China
| | - F. Vanessa Loiacono
- Max Planck Institut für Molekulare Pflanzenphysiologie, Department III, D-14476 Potsdam-Golm, Germany
| | - Stephanie Ruf
- Max Planck Institut für Molekulare Pflanzenphysiologie, Department III, D-14476 Potsdam-Golm, Germany
| | - Jiang Zhang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Ralph Bock
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan 430062, China
- Max Planck Institut für Molekulare Pflanzenphysiologie, Department III, D-14476 Potsdam-Golm, Germany
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14
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Smith DR. Genome evolution: Minicircular mtDNA and unusual heteroplasmy in a parasitic plant. Curr Biol 2022; 32:R86-R89. [DOI: 10.1016/j.cub.2021.12.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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15
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The minicircular and extremely heteroplasmic mitogenome of the holoparasitic plant Rhopalocnemis phalloides. Curr Biol 2021; 32:470-479.e5. [PMID: 34906352 DOI: 10.1016/j.cub.2021.11.053] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 10/25/2021] [Accepted: 11/22/2021] [Indexed: 12/14/2022]
Abstract
The plastid and nuclear genomes of parasitic plants exhibit deeply altered architectures,1-13 whereas the few examined mitogenomes range from deeply altered to conventional.14-20 To provide further insight on mitogenome evolution in parasitic plants, we report the highly modified mitogenome of Rhopalocnemis phalloides, a holoparasite in Balanophoraceae. Its mitogenome is uniquely arranged in 21 minicircular chromosomes that vary in size from 4,949 to 7,861 bp, with a total length of only 130,713 bp. All chromosomes share an identical 896 bp conserved region, with a large stem-loop that acts as the origin of replication, flanked on each side by hypervariable and semi-conserved regions. Similar minicircular structures with shared and unique regions have been observed in parasitic animals and free-living protists,21-24 suggesting convergent structural evolution. Southern blots confirm both the minicircular structure and the replication origin of the mitochondrial chromosomes. PacBio reads provide evidence for chromosome recombination and rolling-circle replication for the R. phalloides mitogenome. Despite its small size, the mitogenome harbors a typical set of genes and introns within the unique regions of each chromosome, yet introns are the smallest among seed plants and ferns. The mitogenome also exhibits extreme heteroplasmy, predominantly involving short indels and more complex variants, many of which cause potential loss-of-function mutations for some gene copies. All heteroplasmic variants are transcribed, and functional and nonfunctional protein-coding variants are spliced and RNA edited. Our findings offer a unique perspective into how mitogenomes of parasitic plants can be deeply altered and shed light on plant mitogenome replication.
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16
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Huang CH, Liu YC, Shen JY, Lu FI, Shaw SY, Huang HJ, Chang CC. Repairing TALEN-mediated double-strand break by microhomology-mediated recombination in tobacco plastids generates abundant subgenomic DNA. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2021; 313:111028. [PMID: 34763881 DOI: 10.1016/j.plantsci.2021.111028] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 08/18/2021] [Accepted: 08/19/2021] [Indexed: 06/13/2023]
Abstract
Transcription activator-like effector nuclease (TALEN) technology has been widely used to edit nuclear genomes in plants but rarely for editing organellar genomes. In addition, ciprofloxacin, commonly used to cause the double-strand break of organellar DNA for studying the repair mechanism in plants, confers no organellar selectivity and site-specificity. To demonstrate the feasibility of TALEN-mediated chloroplast DNA editing and to use it for studying the repair mechanism in plastids, we developed a TALEN-mediated editing technology fused with chloroplast transit peptide (cpTALEN) to site-specifically edit the rpoB gene via Agrobacteria-mediated transformation of tobacco leaf. Transgenic plants showed various degrees of chlorotic phenotype. Repairing damaged plastid DNA resulted in point mutation, large deletion and small inversion surrounding the rpoB gene by homologous recombination and/or microhomology-mediated recombination. In an albino line, microhomology-mediated recombination via a pair of 12-bp direct repeats between rpoC2 and ycf2 genes generated the chimeric ycf2-rpoC2 subgenome, with the level about 3- to 5-fold higher for subgenomic DNA than ycf2. Additionally, the expression of chimeric ycf2-rpoC2 transcripts versus ycf2 mRNA agreed well with the level of corresponding DNA. The ycf2-rpoC2 subgenomic DNA might independently and preferentially replicate in plastids.
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Affiliation(s)
- Chih-Hao Huang
- Institute of Biotechnology, National Cheng Kung University, Tainan, 701, Taiwan; Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan, 701, Taiwan
| | - Yu-Chang Liu
- Institute of Biotechnology, National Cheng Kung University, Tainan, 701, Taiwan; Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan, 701, Taiwan
| | - Jia-Yi Shen
- Institute of Biotechnology, National Cheng Kung University, Tainan, 701, Taiwan; Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan, 701, Taiwan
| | - Fu-I Lu
- Institute of Biotechnology, National Cheng Kung University, Tainan, 701, Taiwan; Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan, 701, Taiwan
| | - Shyh-Yu Shaw
- Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan, 701, Taiwan; Department of Chemistry, National Cheng Kung University, Tainan, 701, Taiwan
| | - Hao-Jen Huang
- Department of Life Sciences, National Cheng Kung University, Tainan, 701, Taiwan; Institute of Tropical Plant Sciences and Microbiology, National Cheng Kung University, Tainan, 701, Taiwan
| | - Ching-Chun Chang
- Institute of Biotechnology, National Cheng Kung University, Tainan, 701, Taiwan; Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan, 701, Taiwan; Institute of Tropical Plant Sciences and Microbiology, National Cheng Kung University, Tainan, 701, Taiwan.
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17
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García-Medel PL, Peralta-Castro A, Baruch-Torres N, Fuentes-Pascacio A, Pedroza-García JA, Cruz-Ramirez A, Brieba LG. Arabidopsis thaliana PrimPol is a primase and lesion bypass DNA polymerase with the biochemical characteristics to cope with DNA damage in the nucleus, mitochondria, and chloroplast. Sci Rep 2021; 11:20582. [PMID: 34663822 PMCID: PMC8523556 DOI: 10.1038/s41598-021-00151-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 10/07/2021] [Indexed: 11/09/2022] Open
Abstract
PrimPol is a novel Primase–Polymerase that synthesizes RNA and DNA primers de novo and extents from these primers as a DNA polymerase. Animal PrimPol is involved in nuclear and mitochondrial DNA replication by virtue of its translesion DNA synthesis (TLS) and repriming activities. Here we report that the plant model Arabidopsis thaliana encodes a functional PrimPol (AtPrimPol). AtPrimPol is a low fidelity and a TLS polymerase capable to bypass DNA lesions, like thymine glycol and abasic sites, by incorporating directly across these lesions or by skipping them. AtPrimPol is also an efficient primase that preferentially recognizes the single-stranded 3′-GTCG-5′ DNA sequence, where the 3′-G is cryptic. AtPrimPol is the first DNA polymerase that localizes in three cellular compartments: nucleus, mitochondria, and chloroplast. In vitro, AtPrimPol synthesizes primers that are extended by the plant organellar DNA polymerases and this reaction is regulated by organellar single-stranded binding proteins. Given the constant exposure of plants to endogenous and exogenous DNA-damaging agents and the enzymatic capabilities of lesion bypass and re-priming of AtPrimPol, we postulate a predominant role of this enzyme in avoiding replication fork collapse in all three plant genomes, both as a primase and as a TLS polymerase.
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Affiliation(s)
- Paola L García-Medel
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 629, Km. 9.6 Libramiento Norte Carretera, Irapuato-León, CP 36821, Irapuato, Guanajuato, Mexico
| | - Antolín Peralta-Castro
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 629, Km. 9.6 Libramiento Norte Carretera, Irapuato-León, CP 36821, Irapuato, Guanajuato, Mexico
| | - Noe Baruch-Torres
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 629, Km. 9.6 Libramiento Norte Carretera, Irapuato-León, CP 36821, Irapuato, Guanajuato, Mexico.,Department of Pharmacology and Toxicology, The University of Texas Medical Branch at Galveston, Galveston, TX, 77555, USA
| | - Alma Fuentes-Pascacio
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 629, Km. 9.6 Libramiento Norte Carretera, Irapuato-León, CP 36821, Irapuato, Guanajuato, Mexico
| | - José A Pedroza-García
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Apartado Postal 510-3, 62250, Cuernavaca, Morelos, Mexico
| | - Alfredo Cruz-Ramirez
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 629, Km. 9.6 Libramiento Norte Carretera, Irapuato-León, CP 36821, Irapuato, Guanajuato, Mexico
| | - Luis G Brieba
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 629, Km. 9.6 Libramiento Norte Carretera, Irapuato-León, CP 36821, Irapuato, Guanajuato, Mexico.
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18
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Charboneau JLM, Cronn RC, Liston A, Wojciechowski MF, Sanderson MJ. Plastome Structural Evolution and Homoplastic Inversions in Neo-Astragalus (Fabaceae). Genome Biol Evol 2021; 13:evab215. [PMID: 34534296 PMCID: PMC8486006 DOI: 10.1093/gbe/evab215] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/10/2021] [Indexed: 12/23/2022] Open
Abstract
The plastid genomes of photosynthetic green plants have largely maintained conserved gene content and order as well as structure over hundreds of millions of years of evolution. Several plant lineages, however, have departed from this conservation and contain many plastome structural rearrangements, which have been associated with an abundance of repeated sequences both overall and near rearrangement endpoints. We sequenced the plastomes of 25 taxa of Astragalus L. (Fabaceae), a large genus in the inverted repeat-lacking clade of legumes, to gain a greater understanding of the connection between repeats and plastome inversions. We found plastome repeat structure has a strong phylogenetic signal among these closely related taxa mostly in the New World clade of Astragalus called Neo-Astragalus. Taxa without inversions also do not differ substantially in their overall repeat structure from four taxa each with one large-scale inversion. For two taxa with inversion endpoints between the same pairs of genes, differences in their exact endpoints indicate the inversions occurred independently. Our proposed mechanism for inversion formation suggests the short inverted repeats now found near the endpoints of the four inversions may be there as a result of these inversions rather than their cause. The longer inverted repeats now near endpoints may have allowed the inversions first mediated by shorter microhomologous sequences to propagate, something that should be considered in explaining how any plastome rearrangement becomes fixed regardless of the mechanism of initial formation.
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Affiliation(s)
- Joseph L M Charboneau
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona, USA
| | - Richard C Cronn
- Pacific Northwest Research Station, USDA Forest Service, Corvallis, Oregon, USA
| | - Aaron Liston
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA
| | | | - Michael J Sanderson
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona, USA
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19
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Xia H, Zhao W, Shi Y, Wang XR, Wang B. Microhomologies Are Associated with Tandem Duplications and Structural Variation in Plant Mitochondrial Genomes. Genome Biol Evol 2021; 12:1965-1974. [PMID: 32790831 PMCID: PMC7643612 DOI: 10.1093/gbe/evaa172] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/09/2020] [Indexed: 12/15/2022] Open
Abstract
Short tandem repeats (STRs) contribute to structural variation in plant mitochondrial genomes, but the mechanisms underlying their formation and expansion are unclear. In this study, we detected high polymorphism in the nad7-1 region of the Pinus tabuliformis mitogenome caused by the rapid accumulation of STRs and rearrangements over a few million years ago. The STRs in nad7-1 have a 7-bp microhomology (TAG7) flanking the repeat array. We then scanned the mitogenomes of 136 seed plants to understand the role of microhomology in the formation of STR and mitogenome evolution. A total of 13,170 STRs were identified, and almost half of them were associated with microhomologies. A substantial amount (1,197) of microhomologies was long enough to mediate structural variation, and the length of microhomology is positively correlated with the length of tandem repeat unit. These results suggest that microhomology may be involved in the formation of tandem repeat via microhomology-mediated pathway, and the formation of longer duplicates required greater length of microhomology. We examined the abundance of these 1,197 microhomologies, and found 75% of them were enriched in the plant mitogenomes. Further analyses of the 400 prevalent microhomologies revealed that 175 of them showed differential enrichment between angiosperms and gymnosperms and 186 differed between angiosperms and conifers, indicating lineage-specific usage and expansion of microhomologies. Our study sheds light on the sources of structural variation in plant mitochondrial genomes and highlights the importance of microhomology in mitochondrial genome evolution.
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Affiliation(s)
- Hanhan Xia
- College of Horticulture and Landscape Architecture, Zhongkai University of Agriculture and Engineering, Guangzhou, China
| | - Wei Zhao
- National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Technology, Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing, China
- Department of Ecology and Environmental Science, UPSC, Umeå University, Umeå, Sweden
| | - Yong Shi
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- Center of Conservation Biology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Xiao-Ru Wang
- National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Technology, Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing, China
- Department of Ecology and Environmental Science, UPSC, Umeå University, Umeå, Sweden
| | - Baosheng Wang
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- Center of Conservation Biology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- Corresponding author: E-mail:
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Mahapatra K, Banerjee S, De S, Mitra M, Roy P, Roy S. An Insight Into the Mechanism of Plant Organelle Genome Maintenance and Implications of Organelle Genome in Crop Improvement: An Update. Front Cell Dev Biol 2021; 9:671698. [PMID: 34447743 PMCID: PMC8383295 DOI: 10.3389/fcell.2021.671698] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 07/21/2021] [Indexed: 12/19/2022] Open
Abstract
Besides the nuclear genome, plants possess two small extra chromosomal genomes in mitochondria and chloroplast, respectively, which contribute a small fraction of the organelles’ proteome. Both mitochondrial and chloroplast DNA have originated endosymbiotically and most of their prokaryotic genes were either lost or transferred to the nuclear genome through endosymbiotic gene transfer during the course of evolution. Due to their immobile nature, plant nuclear and organellar genomes face continuous threat from diverse exogenous agents as well as some reactive by-products or intermediates released from various endogenous metabolic pathways. These factors eventually affect the overall plant growth and development and finally productivity. The detailed mechanism of DNA damage response and repair following accumulation of various forms of DNA lesions, including single and double-strand breaks (SSBs and DSBs) have been well documented for the nuclear genome and now it has been extended to the organelles also. Recently, it has been shown that both mitochondria and chloroplast possess a counterpart of most of the nuclear DNA damage repair pathways and share remarkable similarities with different damage repair proteins present in the nucleus. Among various repair pathways, homologous recombination (HR) is crucial for the repair as well as the evolution of organellar genomes. Along with the repair pathways, various other factors, such as the MSH1 and WHIRLY family proteins, WHY1, WHY2, and WHY3 are also known to be involved in maintaining low mutation rates and structural integrity of mitochondrial and chloroplast genome. SOG1, the central regulator in DNA damage response in plants, has also been found to mediate endoreduplication and cell-cycle progression through chloroplast to nucleus retrograde signaling in response to chloroplast genome instability. Various proteins associated with the maintenance of genome stability are targeted to both nuclear and organellar compartments, establishing communication between organelles as well as organelles and nucleus. Therefore, understanding the mechanism of DNA damage repair and inter compartmental crosstalk mechanism in various sub-cellular organelles following induction of DNA damage and identification of key components of such signaling cascades may eventually be translated into strategies for crop improvement under abiotic and genotoxic stress conditions. This review mainly highlights the current understanding as well as the importance of different aspects of organelle genome maintenance mechanisms in higher plants.
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Affiliation(s)
- Kalyan Mahapatra
- Department of Botany, UGC Center for Advanced Studies, The University of Burdwan, Burdwan, India
| | - Samrat Banerjee
- Department of Botany, UGC Center for Advanced Studies, The University of Burdwan, Burdwan, India
| | - Sayanti De
- Department of Botany, UGC Center for Advanced Studies, The University of Burdwan, Burdwan, India
| | - Mehali Mitra
- Department of Botany, UGC Center for Advanced Studies, The University of Burdwan, Burdwan, India
| | - Pinaki Roy
- Department of Botany, UGC Center for Advanced Studies, The University of Burdwan, Burdwan, India
| | - Sujit Roy
- Department of Botany, UGC Center for Advanced Studies, The University of Burdwan, Burdwan, India
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21
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Wang W, Li K, Yang Z, Hou Q, Zhao WW, Sun Q. RNase H1C collaborates with ssDNA binding proteins WHY1/3 and recombinase RecA1 to fulfill the DNA damage repair in Arabidopsis chloroplasts. Nucleic Acids Res 2021; 49:6771-6787. [PMID: 34133716 PMCID: PMC8266629 DOI: 10.1093/nar/gkab479] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 04/25/2021] [Accepted: 05/19/2021] [Indexed: 12/28/2022] Open
Abstract
Proper repair of damaged DNA is crucial for genetic integrity and organismal survival. As semi-autonomous organelles, plastids have their own genomes whose integrity must be preserved. Several factors have been shown to participate in plastid DNA damage repair; however, the underlying mechanism remains unclear. Here, we elucidate a mechanism of homologous recombination (HR) repair in chloroplasts that involves R-loops. We find that the recombinase RecA1 forms filaments in chloroplasts during HR repair, but aggregates as puncta when RNA:DNA hybrids accumulate. ssDNA-binding proteins WHY1/3 and chloroplast RNase H1 AtRNH1C are recruited to the same genomic sites to promote HR repair. Depletion of AtRNH1C or WHY1/3 significantly suppresses the binding of RNA polymerase to the damaged DNA, thus reducing HR repair and modulating microhomology-mediated double-strand break repair. Furthermore, we show that DNA polymerase IB works with AtRNH1C genetically to complete the DNA damage repair process. This study reveals the positive role of R-loops in facilitating the activities of WHY1/3 and RecA1, which in turn secures HR repair and organellar development.
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Affiliation(s)
- Wenjie Wang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Kuan Li
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Zhuo Yang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Quancan Hou
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Wei W Zhao
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Qianwen Sun
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
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22
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Choi IS, Wojciechowski MF, Ruhlman TA, Jansen RK. In and out: Evolution of viral sequences in the mitochondrial genomes of legumes (Fabaceae). Mol Phylogenet Evol 2021; 163:107236. [PMID: 34147655 DOI: 10.1016/j.ympev.2021.107236] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 06/11/2021] [Accepted: 06/14/2021] [Indexed: 10/21/2022]
Abstract
Plant specific mitoviruses in the 'genus' Mitovirus (Narnaviridae) and their integrated sequences (non-retroviral endogenous RNA viral elements or NERVEs) have been recently identified in various plant lineages. However, the sparse phylogenetic coverage of complete plant mitochondrial genome (mitogenome) sequences and the non-conserved nature of mitochondrial intergenic regions have hindered comparative studies on mitovirus NERVEs in plants. In this study, 10 new mitogenomes were sequenced from legumes (Fabaceae). Based on comparative genomic analysis of 27 total mitogenomes, we identified mitovirus NERVEs and transposable elements across the family. All legume mitogenomes included NERVEs and total NERVE length varied from ca. 2 kb in the papilionoid Trifolium to 35 kb in the mimosoid Acacia. Most of the NERVE integration sites were in highly variable intergenic regions, however, some were positioned in six cis-spliced mitochondrial introns. In the Acacia mitogenome, there were L1-like transposon sequences including an almost full-length copy with target site duplications (TSDs). The integration sites of NERVEs in four introns showed evidence of L1-like retrotransposition events. Phylogenetic analysis revealed that there were multiple instances of precise deletion of NERVEs between TSDs. This study provides clear evidence that a L1-like retrotransposition mechanism has a long history of contributing to the integration of viral RNA into plant mitogenomes while microhomology-mediated deletion can restore the integration site.
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Affiliation(s)
- In-Su Choi
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA; School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA.
| | | | - Tracey A Ruhlman
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA.
| | - Robert K Jansen
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA; Centre of Excellence in Bionanoscience Research, Department of Biological Sciences, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia.
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23
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Chowdhury S, Chowdhury AB, Kumar M, Chakraborty S. Revisiting regulatory roles of replication protein A in plant DNA metabolism. PLANTA 2021; 253:130. [PMID: 34047822 DOI: 10.1007/s00425-021-03641-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 05/19/2021] [Indexed: 06/12/2023]
Abstract
This review provides insight into the roles of heterotrimeric RPA protein complexes encompassing all aspects of DNA metabolism in plants along with specific function attributed by individual subunits. It highlights research gaps that need further attention. Replication protein A (RPA), a heterotrimeric protein complex partakes in almost every aspect of DNA metabolism in eukaryotes with its principle role being a single-stranded DNA-binding protein, thereby providing stability to single-stranded (ss) DNA. Although most of our knowledge of RPA structure and its role in DNA metabolism is based on studies in yeast and animal system, in recent years, plants have also been reported to have diverse repertoire of RPA complexes (formed by combination of different RPA subunit homologs arose during course of evolution), expected to be involved in plethora of DNA metabolic activities. Here, we have reviewed all studies regarding role of RPA in DNA metabolism in plants. As combination of plant RPA complexes may vary largely depending on number of homologs of each subunit, next step for plant biologists is to develop specific functional methods for detailed analysis of biological roles of these complexes, which we have tried to formulate in our review. Besides, complete absence of any study regarding regulatory role of posttranslational modification of RPA complexes in DNA metabolism in plants, prompts us to postulate a hypothetical model of same in light of information from animal system. With our review, we envisage to stimulate the RPA research in plants to shift its course from descriptive to functional studies, thereby bringing a new angle of studying dynamic DNA metabolism in plants.
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Affiliation(s)
- Supriyo Chowdhury
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Arpita Basu Chowdhury
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Manish Kumar
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Supriya Chakraborty
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
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24
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Ji J, Day A. Construction of a highly error-prone DNA polymerase for developing organelle mutation systems. Nucleic Acids Res 2020; 48:11868-11879. [PMID: 33135056 PMCID: PMC7708058 DOI: 10.1093/nar/gkaa929] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 09/30/2020] [Accepted: 10/06/2020] [Indexed: 12/21/2022] Open
Abstract
A novel family of DNA polymerases replicates organelle genomes in a wide distribution of taxa encompassing plants and protozoans. Making error-prone mutator versions of gamma DNA polymerases revolutionised our understanding of animal mitochondrial genomes but similar advances have not been made for the organelle DNA polymerases present in plant mitochondria and chloroplasts. We tested the fidelities of error prone tobacco organelle DNA polymerases using a novel positive selection method involving replication of the phage lambda cI repressor gene. Unlike gamma DNA polymerases, ablation of 3'-5' exonuclease function resulted in a modest 5-8-fold error rate increase. Combining exonuclease deficiency with a polymerisation domain substitution raised the organelle DNA polymerase error rate by 140-fold relative to the wild type enzyme. This high error rate compares favourably with error-rates of mutator versions of animal gamma DNA polymerases. The error prone organelle DNA polymerase introduced mutations at multiple locations ranging from two to seven sites in half of the mutant cI genes studied. Single base substitutions predominated including frequent A:A (template: dNMP) mispairings. High error rate and semi-dominance to the wild type enzyme in vitro make the error prone organelle DNA polymerase suitable for elevating mutation rates in chloroplasts and mitochondria.
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MESH Headings
- Amino Acid Sequence
- Bacterial Outer Membrane Proteins/chemistry
- Bacterial Outer Membrane Proteins/genetics
- Bacterial Outer Membrane Proteins/metabolism
- Binding Sites
- Chloroplasts/genetics
- Chloroplasts/metabolism
- Cloning, Molecular
- DNA Polymerase gamma/chemistry
- DNA Polymerase gamma/genetics
- DNA Polymerase gamma/metabolism
- DNA Replication
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Gene Expression
- Genetic Vectors/chemistry
- Genetic Vectors/metabolism
- Mitochondria/genetics
- Mitochondria/metabolism
- Models, Molecular
- Mutation
- Phylogeny
- Plant Proteins/chemistry
- Plant Proteins/genetics
- Plant Proteins/metabolism
- Polymorphism, Single Nucleotide
- Porins/chemistry
- Porins/genetics
- Porins/metabolism
- Protein Binding
- Protein Conformation, alpha-Helical
- Protein Conformation, beta-Strand
- Protein Interaction Domains and Motifs
- Receptors, Virus/chemistry
- Receptors, Virus/genetics
- Receptors, Virus/metabolism
- Recombinant Proteins/chemistry
- Recombinant Proteins/genetics
- Recombinant Proteins/metabolism
- Selection, Genetic
- Sequence Alignment
- Sequence Homology, Amino Acid
- Nicotiana/classification
- Nicotiana/genetics
- Nicotiana/metabolism
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Affiliation(s)
- Junwei Ji
- School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK
| | - Anil Day
- School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK
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25
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The Dark Side of UV-Induced DNA Lesion Repair. Genes (Basel) 2020; 11:genes11121450. [PMID: 33276692 PMCID: PMC7761550 DOI: 10.3390/genes11121450] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 11/27/2020] [Accepted: 11/29/2020] [Indexed: 12/12/2022] Open
Abstract
In their life cycle, plants are exposed to various unfavorable environmental factors including ultraviolet (UV) radiation emitted by the Sun. UV-A and UV-B, which are partially absorbed by the ozone layer, reach the surface of the Earth causing harmful effects among the others on plant genetic material. The energy of UV light is sufficient to induce mutations in DNA. Some examples of DNA damage induced by UV are pyrimidine dimers, oxidized nucleotides as well as single and double-strand breaks. When exposed to light, plants can repair major UV-induced DNA lesions, i.e., pyrimidine dimers using photoreactivation. However, this highly efficient light-dependent DNA repair system is ineffective in dim light or at night. Moreover, it is helpless when it comes to the repair of DNA lesions other than pyrimidine dimers. In this review, we have focused on how plants cope with deleterious DNA damage that cannot be repaired by photoreactivation. The current understanding of light-independent mechanisms, classified as dark DNA repair, indispensable for the maintenance of plant genetic material integrity has been presented.
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26
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Peralta-Castro A, García-Medel PL, Baruch-Torres N, Trasviña-Arenas CH, Juarez-Quintero V, Morales-Vazquez CM, Brieba LG. Plant Organellar DNA Polymerases Evolved Multifunctionality through the Acquisition of Novel Amino Acid Insertions. Genes (Basel) 2020; 11:genes11111370. [PMID: 33228188 PMCID: PMC7699545 DOI: 10.3390/genes11111370] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 11/15/2020] [Accepted: 11/17/2020] [Indexed: 12/20/2022] Open
Abstract
The majority of DNA polymerases (DNAPs) are specialized enzymes with specific roles in DNA replication, translesion DNA synthesis (TLS), or DNA repair. The enzymatic characteristics to perform accurate DNA replication are in apparent contradiction with TLS or DNA repair abilities. For instance, replicative DNAPs incorporate nucleotides with high fidelity and processivity, whereas TLS DNAPs are low-fidelity polymerases with distributive nucleotide incorporation. Plant organelles (mitochondria and chloroplast) are replicated by family-A DNA polymerases that are both replicative and TLS DNAPs. Furthermore, plant organellar DNA polymerases from the plant model Arabidopsis thaliana (AtPOLIs) execute repair of double-stranded breaks by microhomology-mediated end-joining and perform Base Excision Repair (BER) using lyase and strand-displacement activities. AtPOLIs harbor three unique insertions in their polymerization domain that are associated with TLS, microhomology-mediated end-joining (MMEJ), strand-displacement, and lyase activities. We postulate that AtPOLIs are able to execute those different functions through the acquisition of these novel amino acid insertions, making them multifunctional enzymes able to participate in DNA replication and DNA repair.
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Affiliation(s)
- Antolín Peralta-Castro
- Laboratorio Nacional de Genomica para la Biodiversidad, Centro de Investigacion y de Estudios Avanzados del IPN, Apartado Postal 629, Irapuato CP 36821, Mexico; (A.P.-C.); (P.L.G.-M.); (N.B.-T.); (C.H.T.-A.); (V.J.-Q.); (C.M.M.-V.)
| | - Paola L. García-Medel
- Laboratorio Nacional de Genomica para la Biodiversidad, Centro de Investigacion y de Estudios Avanzados del IPN, Apartado Postal 629, Irapuato CP 36821, Mexico; (A.P.-C.); (P.L.G.-M.); (N.B.-T.); (C.H.T.-A.); (V.J.-Q.); (C.M.M.-V.)
| | - Noe Baruch-Torres
- Laboratorio Nacional de Genomica para la Biodiversidad, Centro de Investigacion y de Estudios Avanzados del IPN, Apartado Postal 629, Irapuato CP 36821, Mexico; (A.P.-C.); (P.L.G.-M.); (N.B.-T.); (C.H.T.-A.); (V.J.-Q.); (C.M.M.-V.)
| | - Carlos H. Trasviña-Arenas
- Laboratorio Nacional de Genomica para la Biodiversidad, Centro de Investigacion y de Estudios Avanzados del IPN, Apartado Postal 629, Irapuato CP 36821, Mexico; (A.P.-C.); (P.L.G.-M.); (N.B.-T.); (C.H.T.-A.); (V.J.-Q.); (C.M.M.-V.)
- Department of Chemistry, University of California, Davis, One Shields Ave, Davis, CA 95616, USA
| | - Víctor Juarez-Quintero
- Laboratorio Nacional de Genomica para la Biodiversidad, Centro de Investigacion y de Estudios Avanzados del IPN, Apartado Postal 629, Irapuato CP 36821, Mexico; (A.P.-C.); (P.L.G.-M.); (N.B.-T.); (C.H.T.-A.); (V.J.-Q.); (C.M.M.-V.)
| | - Carlos M. Morales-Vazquez
- Laboratorio Nacional de Genomica para la Biodiversidad, Centro de Investigacion y de Estudios Avanzados del IPN, Apartado Postal 629, Irapuato CP 36821, Mexico; (A.P.-C.); (P.L.G.-M.); (N.B.-T.); (C.H.T.-A.); (V.J.-Q.); (C.M.M.-V.)
| | - Luis G. Brieba
- Laboratorio Nacional de Genomica para la Biodiversidad, Centro de Investigacion y de Estudios Avanzados del IPN, Apartado Postal 629, Irapuato CP 36821, Mexico; (A.P.-C.); (P.L.G.-M.); (N.B.-T.); (C.H.T.-A.); (V.J.-Q.); (C.M.M.-V.)
- Correspondence: ; Tel.: +52-462-1663007
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27
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Plant organellar DNA polymerases bypass thymine glycol using two conserved lysine residues. Biochem J 2020; 477:1049-1059. [PMID: 32108856 DOI: 10.1042/bcj20200043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 02/25/2020] [Accepted: 02/28/2020] [Indexed: 02/07/2023]
Abstract
Plant organelles cope with endogenous DNA damaging agents, byproducts of respiration and photosynthesis, and exogenous agents like ultraviolet light. Plant organellar DNA polymerases (DNAPs) are not phylogenetically related to yeast and metazoan DNAPs and they harbor three insertions not present in any other DNAPs. Plant organellar DNAPs from Arabidopsis thaliana (AtPolIA and AtPolIB) are translesion synthesis (TLS) DNAPs able to bypass abasic sites, a lesion that poses a strong block to replicative polymerases. Besides abasic sites, reactive oxidative species and ionizing radiation react with thymine resulting in thymine glycol (Tg), a DNA adduct that is also a strong block to replication. Here, we report that AtPolIA and AtPolIB bypass Tg by inserting an adenine opposite the lesion and efficiently extend from a Tg-A base pair. The TLS ability of AtPolIB is mapped to two conserved lysine residues: K593 and K866. Residue K593 is situated in insertion 1 and K866 is in insertion 3. With basis on the location of both insertions on a structural model of AtPolIIB, we hypothesize that the two positively charged residues interact to form a clamp around the primer-template. In contrast with nuclear and bacterial replication, where lesion bypass involves an interplay between TLS and replicative DNA polymerases, we postulate that plant organellar DNAPs evolved to exert replicative and TLS activities.
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28
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Sugimoto H, Hirano M, Tanaka H, Tanaka T, Kitagawa-Yogo R, Muramoto N, Mitsukawa N. Plastid-targeted forms of restriction endonucleases enhance the plastid genome rearrangement rate and trigger the reorganization of its genomic architecture. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 102:1042-1057. [PMID: 31925982 DOI: 10.1111/tpj.14687] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 12/25/2019] [Accepted: 01/02/2020] [Indexed: 06/10/2023]
Abstract
Plant cells have acquired chloroplasts (plastids) with a unique genome (ptDNA), which developed during the evolution of endosymbiosis. The gene content and genome structure of ptDNAs in land plants are considerably stable, although those of algal ptDNAs are highly varied. Plant cells seem, therefore, to be intolerant of any structural or organizational changes in the ptDNA. Genome rearrangement functions as a driver of genomic evolutionary divergence. Here, we aimed to create various types of rearrangements in the ptDNA of Arabidopsis genomes using plastid-targeted forms of restriction endonucleases (pREs). Arabidopsis plants expressing each of the three specific pREs, i.e., pTaqI, pHinP1I, and pMseI, were generated; they showed the leaf variegation phenotypes associated with impaired chloroplast development. We confirmed that these pREs caused double-stranded breaks (DSB) at their recognition sites in ptDNAs. Genome-wide analysis of ptDNAs revealed that the transgenic lines exhibited a large number of rearrangements such as inversions and deletions/duplications, which were dominantly repaired by microhomology-mediated recombination and microhomology-mediated end-joining, and less by non-homologous end-joining. Notably, pHinP1I, which recognized a small number of sites in ptDNA, induced drastic structural changes, including regional copy number variations throughout ptDNAs. In contrast, the transient expression of either pTaqI or pMseI, whose recognition site numbers were relatively larger, resulted in small-scale changes at the whole genome level. These results indicated that DSB frequencies and their distribution are major determinants in shaping ptDNAs.
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Affiliation(s)
- Hiroki Sugimoto
- Genome Engineering Program, Strategic Research Division, Toyota Central R&D Laboratories, Inc., Nagakute, Aichi, 480-1192, Japan
| | - Minoru Hirano
- Bio System Engineering Program, Strategic Research Division, Toyota Central R&D Laboratories, Inc., Nagakute, Aichi, 480-1192, Japan
| | - Hidenori Tanaka
- Genome Engineering Program, Strategic Research Division, Toyota Central R&D Laboratories, Inc., Nagakute, Aichi, 480-1192, Japan
| | - Tomoko Tanaka
- Genome Engineering Program, Strategic Research Division, Toyota Central R&D Laboratories, Inc., Nagakute, Aichi, 480-1192, Japan
| | - Ritsuko Kitagawa-Yogo
- Genome Engineering Program, Strategic Research Division, Toyota Central R&D Laboratories, Inc., Nagakute, Aichi, 480-1192, Japan
| | - Nobuhiko Muramoto
- Genome Engineering Program, Strategic Research Division, Toyota Central R&D Laboratories, Inc., Nagakute, Aichi, 480-1192, Japan
| | - Norihiro Mitsukawa
- Genome Engineering Program, Strategic Research Division, Toyota Central R&D Laboratories, Inc., Nagakute, Aichi, 480-1192, Japan
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29
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Golin S, Negroni YL, Bennewitz B, Klösgen RB, Mulisch M, La Rocca N, Cantele F, Vigani G, Lo Schiavo F, Krupinska K, Zottini M. WHIRLY2 plays a key role in mitochondria morphology, dynamics, and functionality in Arabidopsis thaliana. PLANT DIRECT 2020; 4:e00229. [PMID: 32490348 PMCID: PMC7261051 DOI: 10.1002/pld3.229] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 04/18/2020] [Accepted: 04/24/2020] [Indexed: 06/02/2023]
Abstract
WHIRLY2 is a single-stranded DNA binding protein associated with mitochondrial nucleoids. In the why 2-1 mutant of Arabidopsis thaliana, a major proportion of leaf mitochondria has an aberrant structure characterized by disorganized nucleoids, reduced abundance of cristae, and a low matrix density despite the fact that the macroscopic phenotype during vegetative growth is not different from wild type. These features coincide with an impairment of the functionality and dynamics of mitochondria that have been characterized in detail in wild-type and why 2-1 mutant cell cultures. In contrast to the development of the vegetative parts, seed germination is compromised in the why 2-1 mutant. In line with that, the expression level of why 2 in seeds of wild-type plants is higher than that of why 3, whereas in adult plant no difference is found. Intriguingly, in early stages of shoots development of the why 2-1 mutant, although not in seeds, the expression level of why 3 is enhanced. These results suggest that WHIRLY3 is a potential candidate to compensate for the lack of WHIRLY2 in the why 2-1 mutant. Such compensation is possible only if the two proteins are localized in the same organelle. Indeed, in organello protein transport experiments using intact mitochondria and chloroplasts revealed that WHIRLY3 can be dually targeted into both, chloroplasts and mitochondria. Together, these data indicate that the alterations of mitochondria nucleoids are tightly linked to alterations of mitochondria morphology and functionality. This is even more evident in those phases of plant life when mitochondrial activity is particularly high, such as seed germination. Moreover, our results indicate that the differential expression of why 2 and why 3 predetermines the functional replacement of WHIRLY2 by WHIRLY3, which is restricted though to the vegetative parts of the plant.
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Affiliation(s)
- Serena Golin
- Department of Biology University of Padova Padova Italy
| | | | - Bationa Bennewitz
- Institute of Biology-Plant Physiology Martin Luther University Halle-Wittenberg Halle (Saale) Germany
| | - Ralf B Klösgen
- Institute of Biology-Plant Physiology Martin Luther University Halle-Wittenberg Halle (Saale) Germany
| | - Maria Mulisch
- Institute of Botany Christian-Albrechts University of Kiel Kiel Germany
| | | | | | - Gianpiero Vigani
- Department of Life Science and Systems Biology University of Turin Turin Italy
| | | | - Karin Krupinska
- Institute of Botany Christian-Albrechts University of Kiel Kiel Germany
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30
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Wynn E, Purfeerst E, Christensen A. Mitochondrial DNA Repair in an Arabidopsis thaliana Uracil N-Glycosylase Mutant. PLANTS (BASEL, SWITZERLAND) 2020; 9:E261. [PMID: 32085412 PMCID: PMC7076443 DOI: 10.3390/plants9020261] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 02/14/2020] [Accepted: 02/16/2020] [Indexed: 02/07/2023]
Abstract
Substitution rates in plant mitochondrial genes are extremely low, indicating strong selective pressure as well as efficient repair. Plant mitochondria possess base excision repair pathways; however, many repair pathways such as nucleotide excision repair and mismatch repair appear to be absent. In the absence of these pathways, many DNA lesions must be repaired by a different mechanism. To test the hypothesis that double-strand break repair (DSBR) is that mechanism, we maintained independent self-crossing lineages of plants deficient in uracil-N-glycosylase (UNG) for 11 generations to determine the repair outcomes when that pathway is missing. Surprisingly, no single nucleotide polymorphisms (SNPs) were fixed in any line in generation 11. The pattern of heteroplasmic SNPs was also unaltered through 11 generations. When the rate of cytosine deamination was increased by mitochondrial expression of the cytosine deaminase APOBEC3G, there was an increase in heteroplasmic SNPs but only in mature leaves. Clearly, DNA maintenance in reproductive meristem mitochondria is very effective in the absence of UNG while mitochondrial genomes in differentiated tissue are maintained through a different mechanism or not at all. Several genes involved in DSBR are upregulated in the absence of UNG, indicating that double-strand break repair is a general system of repair in plant mitochondria. It is important to note that the developmental stage of tissues is critically important for these types of experiments.
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Affiliation(s)
- Emily Wynn
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE 68588, USA; (E.W.); (E.P.)
- United States Department of Agriculture, Agricultural Research Service, U.S. Meat Animal Research Center, Clay Center, NE 68933, USA
| | - Emma Purfeerst
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE 68588, USA; (E.W.); (E.P.)
- Athletics Department, Bethany Lutheran College, Mankato, MN 56001, USA
| | - Alan Christensen
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE 68588, USA; (E.W.); (E.P.)
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Chevigny N, Schatz-Daas D, Lotfi F, Gualberto JM. DNA Repair and the Stability of the Plant Mitochondrial Genome. Int J Mol Sci 2020; 21:E328. [PMID: 31947741 PMCID: PMC6981420 DOI: 10.3390/ijms21010328] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 12/27/2019] [Accepted: 01/01/2020] [Indexed: 12/13/2022] Open
Abstract
The mitochondrion stands at the center of cell energy metabolism. It contains its own genome, the mtDNA, that is a relic of its prokaryotic symbiotic ancestor. In plants, the mitochondrial genetic information influences important agronomic traits including fertility, plant vigor, chloroplast function, and cross-compatibility. Plant mtDNA has remarkable characteristics: It is much larger than the mtDNA of other eukaryotes and evolves very rapidly in structure. This is because of recombination activities that generate alternative mtDNA configurations, an important reservoir of genetic diversity that promotes rapid mtDNA evolution. On the other hand, the high incidence of ectopic recombination leads to mtDNA instability and the expression of gene chimeras, with potential deleterious effects. In contrast to the structural plasticity of the genome, in most plant species the mtDNA coding sequences evolve very slowly, even if the organization of the genome is highly variable. Repair mechanisms are probably responsible for such low mutation rates, in particular repair by homologous recombination. Herein we review some of the characteristics of plant organellar genomes and of the repair pathways found in plant mitochondria. We further discuss how homologous recombination is involved in the evolution of the plant mtDNA.
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Affiliation(s)
| | | | | | - José Manuel Gualberto
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, 67081 Strasbourg, France; (N.C.); (D.S.-D.); (F.L.)
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Tripathi D, Nam A, Oldenburg DJ, Bendich AJ. Reactive Oxygen Species, Antioxidant Agents, and DNA Damage in Developing Maize Mitochondria and Plastids. FRONTIERS IN PLANT SCIENCE 2020; 11:596. [PMID: 32508860 PMCID: PMC7248337 DOI: 10.3389/fpls.2020.00596] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 04/20/2020] [Indexed: 05/14/2023]
Abstract
Maize shoot development progresses from non-pigmented meristematic cells at the base of the leaf to expanded and non-dividing green cells of the leaf blade. This transition is accompanied by the conversion of promitochondria and proplastids to their mature forms and massive fragmentation of both mitochondrial DNA (mtDNA) and plastid DNA (ptDNA), collectively termed organellar DNA (orgDNA). We measured developmental changes in reactive oxygen species (ROS), which at high concentrations can lead to oxidative stress and DNA damage, as well as antioxidant agents and oxidative damage in orgDNA. Our plants were grown under normal, non-stressful conditions. Nonetheless, we found more oxidative damage in orgDNA from leaf than stalk tissues and higher levels of hydrogen peroxide, superoxide, and superoxide dismutase in leaf than stalk tissues and in light-grown compared to dark-grown leaves. In both mitochondria and plastids, activities of the antioxidant enzyme peroxidase were higher in stalk than in leaves and in dark-grown than light-grown leaves. In protoplasts, the amount of the small-molecule antioxidants, glutathione and ascorbic acid, and catalase activity were also higher in the stalk than in leaf tissue. The data suggest that the degree of oxidative stress in the organelles is lower in stalk than leaf and lower in dark than light growth conditions. We speculate that the damaged/fragmented orgDNA in leaves (but not the basal meristem) results from ROS signaling to the nucleus to stop delivering DNA repair proteins to mature organelles producing large amounts of ROS.
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Brieba LG. Structure-Function Analysis Reveals the Singularity of Plant Mitochondrial DNA Replication Components: A Mosaic and Redundant System. PLANTS 2019; 8:plants8120533. [PMID: 31766564 PMCID: PMC6963530 DOI: 10.3390/plants8120533] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 11/18/2019] [Accepted: 11/19/2019] [Indexed: 02/06/2023]
Abstract
Plants are sessile organisms, and their DNA is particularly exposed to damaging agents. The integrity of plant mitochondrial and plastid genomes is necessary for cell survival. During evolution, plants have evolved mechanisms to replicate their mitochondrial genomes while minimizing the effects of DNA damaging agents. The recombinogenic character of plant mitochondrial DNA, absence of defined origins of replication, and its linear structure suggest that mitochondrial DNA replication is achieved by a recombination-dependent replication mechanism. Here, I review the mitochondrial proteins possibly involved in mitochondrial DNA replication from a structural point of view. A revision of these proteins supports the idea that mitochondrial DNA replication could be replicated by several processes. The analysis indicates that DNA replication in plant mitochondria could be achieved by a recombination-dependent replication mechanism, but also by a replisome in which primers are synthesized by three different enzymes: Mitochondrial RNA polymerase, Primase-Helicase, and Primase-Polymerase. The recombination-dependent replication model and primers synthesized by the Primase-Polymerase may be responsible for the presence of genomic rearrangements in plant mitochondria.
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Affiliation(s)
- Luis Gabriel Brieba
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 629, Irapuato, Guanajuato C.P. 36821, Mexico
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Abstract
The mitochondrial genome encodes proteins essential for the oxidative phosphorylation and, consequently, for proper mitochondrial function. Its localization and, possibly, structural organization contribute to higher DNA damage accumulation, when compared to the nuclear genome. In addition, the mitochondrial genome mutates at rates several times higher than the nuclear, although the causal relationship between these events are not clearly established. Maintaining mitochondrial DNA stability is critical for cellular function and organismal fitness, and several pathways contribute to that, including damage tolerance and bypass, degradation of damaged genomes and DNA repair. Despite initial evidence suggesting that mitochondria lack DNA repair activities, most DNA repair pathways have been at least partially characterized in mitochondria from several model organisms, including humans. In this chapter, we review what is currently known about how the main DNA repair pathways operate in mitochondria and contribute to mitochondrial DNA stability, with focus on the enzymology of mitochondrial DNA repair.
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Affiliation(s)
- Rebeca R Alencar
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Caio M P F Batalha
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Thiago S Freire
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Nadja C de Souza-Pinto
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil.
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