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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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Li J, Chen Y, Liu Y, Wang C, Li L, Chao Y. Complete mitochondrial genome of Agrostis stolonifera: insights into structure, Codon usage, repeats, and RNA editing. BMC Genomics 2023; 24:466. [PMID: 37596544 PMCID: PMC10439588 DOI: 10.1186/s12864-023-09573-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 08/10/2023] [Indexed: 08/20/2023] Open
Abstract
BACKGROUND Plants possess mitochondrial genomes that are large and complex compared to animals. Despite their size, plant mitochondrial genomes do not contain significantly more genes than their animal counterparts. Studies into the sequence and structure of plant mitochondrial genomes heavily imply that the main mechanism driving replication of plant mtDNA, and offer valuable insights into plant evolution, energy production, and environmental adaptation. RESULTS This study presents the first comprehensive analysis of Agrostis stolonifera's mitochondrial genome, characterized by a branched structure comprising three contiguous chromosomes, totaling 560,800 bp with a GC content of 44.07%. Annotations reveal 33 unique protein-coding genes (PCGs), 19 tRNA genes, and 3 rRNA genes. The predominant codons for alanine and glutamine are GCU and CAA, respectively, while cysteine and phenylalanine exhibit weaker codon usage biases. The mitogenome contains 73, 34, and 23 simple sequence repeats (SSRs) on chromosomes 1, 2, and 3, respectively. Chromosome 1 exhibits the most frequent A-repeat monomeric SSR, whereas chromosome 2 displays the most common U-repeat monomeric SSR. DNA transformation analysis identifies 48 homologous fragments between the mitogenome and chloroplast genome, representing 3.41% of the mitogenome's total length. The PREP suite detects 460 C-U RNA editing events across 33 mitochondrial PCGs, with the highest count in the ccmFn gene and the lowest in the rps7 gene. Phylogenetic analysis confirms A. stolonifera's placement within the Pooideae subfamily, showing a close relationship to Lolium perenne, consistent with the APG IV classification system. Numerous homologous co-linear blocks are observed in A. stolonifera's mitogenomes and those of related species, while certain regions lack homology. CONCLUSIONS The unique features and complexities of the A. stolonifera mitochondrial genome, along with its similarities and differences to related species, provide valuable insights into plant evolution, energy production, and environmental adaptation. The findings from this study significantly contribute to the growing body of knowledge on plant mitochondrial genomes and their role in plant biology.
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Affiliation(s)
- Jiaxing Li
- School of Grassland Science, Beijing Forestry University, Beijing, 100083, China
| | - Yinglong Chen
- UWA School of Agriculture and Environment, The UWA Institute of Agriculture, The University of Western Australia, Perth, WA, 6001, Australia
| | - Yaling Liu
- Inner Mongolia M-Grass Ecology And Environment (Group) Co., Ltd, Hohhot, 010010, China
| | - Chen Wang
- Mentougou District Bureau of Ecological and Environment of Beijing Municipality, Beijing, 102300, China
| | - Ling Li
- Mentougou District Bureau of Ecological and Environment of Beijing Municipality, Beijing, 102300, China
| | - Yuehui Chao
- School of Grassland Science, Beijing Forestry University, Beijing, 100083, China.
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Best C, Mizrahi R, Edris R, Tang H, Zer H, Colas des Francs-Small C, Finkel OM, Zhu H, Small ID, Ostersetzer-Biran O. MSP1 encodes an essential RNA-binding pentatricopeptide repeat factor required for nad1 maturation and complex I biogenesis in Arabidopsis mitochondria. THE NEW PHYTOLOGIST 2023; 238:2375-2392. [PMID: 36922396 DOI: 10.1111/nph.18880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Accepted: 02/23/2023] [Indexed: 05/19/2023]
Abstract
Mitochondrial biogenesis relies on nuclearly encoded factors, which regulate the expression of the organellar-encoded genes. Pentatricopeptide repeat (PPR) proteins constitute a major gene family in angiosperms that are pivotal in many aspects of mitochondrial (mt)RNA metabolism (e.g. trimming, splicing, or stability). Here, we report the analysis of MITOCHONDRIA STABILITY/PROCESSING PPR FACTOR1 (MSP1, At4g20090), a canonical PPR protein that is necessary for mitochondrial functions and embryo development. Loss-of-function allele of MSP1 leads to seed abortion. Here, we employed an embryo-rescue method for the molecular characterization of msp1 mutants. Our analyses reveal that msp1 embryogenesis fails to proceed beyond the heart/torpedo stage as a consequence of a nad1 pre-RNA processing defect, resulting in the loss of respiratory complex I activity. Functional complementation confirmed that msp1 phenotypes result from a disruption of the MSP1 gene. In Arabidopsis, the maturation of nad1 involves the processing of three RNA fragments, nad1.1, nad1.2, and nad1.3. Based on biochemical analyses and mtRNA profiles of wild-type and msp1 plants, we concluded that MSP1 facilitates the generation of the 3' terminus of nad1.1 transcript, a prerequisite for nad1 exons a-b splicing. Our data substantiate the importance of mtRNA metabolism for the biogenesis of the respiratory system during early plant life.
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Affiliation(s)
- Corinne Best
- Department of Plant and Environmental Sciences, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Ron Mizrahi
- Department of Plant and Environmental Sciences, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Rana Edris
- Department of Plant and Environmental Sciences, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Hui Tang
- College of Food Science & Nutritional Engineering, China Agricultural University, Beijing, 100083, China
| | - Hagit Zer
- Department of Plant and Environmental Sciences, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Catherine Colas des Francs-Small
- Australian Research Council Centre of Excellence in Plant Energy Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia
| | - Omri M Finkel
- Department of Plant and Environmental Sciences, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Hongliang Zhu
- College of Food Science & Nutritional Engineering, China Agricultural University, Beijing, 100083, China
| | - Ian D Small
- Australian Research Council Centre of Excellence in Plant Energy Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia
| | - Oren Ostersetzer-Biran
- Department of Plant and Environmental Sciences, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
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Zumkeller S, Knoop V. Categorizing 161 plant (streptophyte) mitochondrial group II introns into 29 families of related paralogues finds only limited links between intron mobility and intron-borne maturases. BMC Ecol Evol 2023; 23:5. [PMID: 36915058 PMCID: PMC10012718 DOI: 10.1186/s12862-023-02108-y] [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: 09/20/2022] [Accepted: 02/27/2023] [Indexed: 03/14/2023] Open
Abstract
Group II introns are common in the two endosymbiotic organelle genomes of the plant lineage. Chloroplasts harbor 22 positionally conserved group II introns whereas their occurrence in land plant (embryophyte) mitogenomes is highly variable and specific for the seven major clades: liverworts, mosses, hornworts, lycophytes, ferns, gymnosperms and flowering plants. Each plant group features "signature selections" of ca. 20-30 paralogues from a superset of altogether 105 group II introns meantime identified in embryophyte mtDNAs, suggesting massive intron gains and losses along the backbone of plant phylogeny. We report on systematically categorizing plant mitochondrial group II introns into "families", comprising evidently related paralogues at different insertion sites, which may even be more similar than their respective orthologues in phylogenetically distant taxa. Including streptophyte (charophyte) algae extends our sampling to 161 and we sort 104 streptophyte mitochondrial group II introns into 25 core families of related paralogues evidently arising from retrotransposition events. Adding to discoveries of only recently created intron paralogues, hypermobile introns and twintrons, our survey led to further discoveries including previously overlooked "fossil" introns in spacer regions or e.g., in the rps8 pseudogene of lycophytes. Initially excluding intron-borne maturase sequences for family categorization, we added an independent analysis of maturase phylogenies and find a surprising incongruence between intron mobility and the presence of intron-borne maturases. Intriguingly, however, we find that several examples of nuclear splicing factors meantime characterized simultaneously facilitate splicing of independent paralogues now placed into the same intron families. Altogether this suggests that plant group II intron mobility, in contrast to their bacterial counterparts, is not intimately linked to intron-encoded maturases.
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Affiliation(s)
- Simon Zumkeller
- IZMB, Institut für Zelluläre und Molekulare Botanik, Abteilung Molekulare Evolution, Universität Bonn, Kirschallee 1, 53115, Bonn, Germany
| | - Volker Knoop
- IZMB, Institut für Zelluläre und Molekulare Botanik, Abteilung Molekulare Evolution, Universität Bonn, Kirschallee 1, 53115, Bonn, Germany.
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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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