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Rose JP, Kriebel R, Sytsma KJ, Drew BT. Phylogenomic perspectives on speciation and reproductive isolation in a North American biodiversity hotspot: an example using California sages (Salvia subgenus Audibertia: Lamiaceae). ANNALS OF BOTANY 2024; 134:295-310. [PMID: 38733329 PMCID: PMC11232522 DOI: 10.1093/aob/mcae073] [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: 02/16/2024] [Accepted: 05/07/2024] [Indexed: 05/13/2024]
Abstract
BACKGROUND AND AIMS The California Floristic Province (CA-FP) is the most species-rich region of North America north of Mexico. One of several proposed hypotheses explaining the exceptional diversity of the region is that the CA-FP harbours myriad recently diverged lineages with nascent reproductive barriers. Salvia subgenus Audibertia is a conspicuous element of the CA-FP, with multiple sympatric and compatible species. METHODS Using 305 nuclear loci and both organellar genomes, we reconstruct species trees, examine genomic discordance, conduct divergence-time estimation, and analyse contemporaneous patterns of gene flow and mechanical reproductive isolation. KEY RESULTS Despite strong genomic discordance, an underlying bifurcating tree is supported. Organellar genomes capture additional introgression events not detected in the nuclear genome. Most interfertility is found within clades, indicating that reproductive barriers arise with increasing genetic divergence. Species are generally not mechanically isolated, suggesting that it is unlikely to be the primary factor leading to reproductive isolation. CONCLUSIONS Rapid, recent speciation with some interspecific gene flow in conjunction with the onset of a Mediterranean-like climate is the underlying cause of extant diversity in Salvia subgenus Audibertia. Speciation has largely not been facilitated by gene flow. Its signal in the nuclear genome seems to mostly be erased by backcrossing, but organellar genomes each capture different instances of historical gene flow, probably characteristic of many CA-FP lineages. Mechanical reproductive isolation appears to be only part of a mosaic of factors limiting gene flow.
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Affiliation(s)
- Jeffrey P Rose
- Department of Biology, University of Nebraska at Kearney, Kearney, NE 68849, USA
- Department of Botany, University of Wisconsin-Madison, 430 Lincoln Drive, Madison, WI 53706, USA
| | - Ricardo Kriebel
- Department of Botany, University of Wisconsin-Madison, 430 Lincoln Drive, Madison, WI 53706, USA
- California Academy of Sciences, San Francisco, CA 94118, USA
| | - Kenneth J Sytsma
- Department of Botany, University of Wisconsin-Madison, 430 Lincoln Drive, Madison, WI 53706, USA
| | - Bryan T Drew
- Department of Biology, University of Nebraska at Kearney, Kearney, NE 68849, USA
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Thureborn O, Wikström N, Razafimandimbison SG, Rydin C. Plastid phylogenomics and cytonuclear discordance in Rubioideae, Rubiaceae. PLoS One 2024; 19:e0302365. [PMID: 38768140 PMCID: PMC11104678 DOI: 10.1371/journal.pone.0302365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 04/03/2024] [Indexed: 05/22/2024] Open
Abstract
In this study of evolutionary relationships in the subfamily Rubioideae (Rubiaceae), we take advantage of the off-target proportion of reads generated via previous target capture sequencing projects based on nuclear genomic data to build a plastome phylogeny and investigate cytonuclear discordance. The assembly of off-target reads resulted in a comprehensive plastome dataset and robust inference of phylogenetic relationships, where most intratribal and intertribal relationships are resolved with strong support. While the phylogenetic results were mostly in agreement with previous studies based on plastome data, novel relationships in the plastid perspective were also detected. For example, our analyses of plastome data provide strong support for the SCOUT clade and its sister relationship to the remaining members of the subfamily, which differs from previous results based on plastid data but agrees with recent results based on nuclear genomic data. However, several instances of highly supported cytonuclear discordance were identified across the Rubioideae phylogeny. Coalescent simulation analysis indicates that while ILS could, by itself, explain the majority of the discordant relationships, plastome introgression may be the better explanation in some cases. Our study further indicates that plastomes across the Rubioideae are, with few exceptions, highly conserved and mainly conform to the structure, gene content, and gene order present in the majority of the flowering plants.
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Affiliation(s)
- Olle Thureborn
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
| | - Niklas Wikström
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
- The Bergius Foundation, The Royal Academy of Sciences, Stockholm, Sweden
| | | | - Catarina Rydin
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
- The Bergius Foundation, The Royal Academy of Sciences, Stockholm, Sweden
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Sakamoto W, Takami T. Plastid Inheritance Revisited: Emerging Role of Organelle DNA Degradation in Angiosperms. PLANT & CELL PHYSIOLOGY 2024; 65:484-492. [PMID: 37702423 DOI: 10.1093/pcp/pcad104] [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: 07/06/2023] [Revised: 08/15/2023] [Accepted: 09/08/2023] [Indexed: 09/14/2023]
Abstract
Plastids are essential organelles in angiosperms and show non-Mendelian inheritance due to their evolution as endosymbionts. In approximately 80% of angiosperms, plastids are thought to be inherited from the maternal parent, whereas other species transmit plastids biparentally. Maternal inheritance can be generally explained by the stochastic segregation of maternal plastids after fertilization because the zygote is overwhelmed by the maternal cytoplasm. In contrast, biparental inheritance shows the transmission of organelles from both parents. In some species, maternal inheritance is not absolute and paternal leakage occurs at a very low frequency (∼10-5). A key process controlling the inheritance mode lies in the behavior of plastids during male gametophyte (pollen) development, with accumulating evidence indicating that the plastids themselves or their DNAs are eliminated during pollen maturation or at fertilization. Cytological observations in numerous angiosperm species have revealed several critical steps that mutually influence the degree of plastid transmission quantitatively among different species. This review revisits plastid inheritance from a mechanistic viewpoint. Particularly, we focus on a recent finding demonstrating that both low temperature and plastid DNA degradation mediated by the organelle exonuclease DEFECTIVE IN POLLEN ORGANELLE DNA DEGRADATION1 (DPD1) influence the degree of paternal leakage significantly in tobacco. Given these findings, we also highlight the emerging role of DPD1 in organelle DNA degradation.
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Affiliation(s)
- Wataru Sakamoto
- Institute of Plant Science and Resources, Okayama University, 2-20-2 Chuo, Kurashiki, Okayama, 710-0046 Japan
| | - Tsuneaki Takami
- Institute of Plant Science and Resources, Okayama University, 2-20-2 Chuo, Kurashiki, Okayama, 710-0046 Japan
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Postel Z, Van Rossum F, Godé C, Schmitt E, Touzet P. Paternal leakage of plastids rescues inter-lineage hybrids in Silene nutans. ANNALS OF BOTANY 2024; 133:427-434. [PMID: 38141228 PMCID: PMC11006537 DOI: 10.1093/aob/mcad196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 12/20/2023] [Indexed: 12/25/2023]
Abstract
BACKGROUND AND AIMS Organelle genomes are usually maternally inherited in angiosperms. However, biparental inheritance has been observed, especially in hybrids resulting from crosses between divergent genetic lineages. When it concerns the plastid genome, this exceptional mode of inheritance might rescue inter-lineage hybrids suffering from plastid-nuclear incompatibilities. Genetically differentiated lineages of Silene nutans exhibit strong postzygotic isolation owing to plastid-nuclear incompatibilities, highlighted by inter-lineage hybrid chlorosis and mortality. Surviving hybrids can exhibit variegated leaves, which might indicate paternal leakage of the plastid genome. We tested whether the surviving hybrids inherited the paternal plastid genome and survived thanks to paternal leakage. METHODS We characterized the leaf phenotype (fully green, variegated or white) of 504 surviving inter-lineage hybrids obtained from a reciprocal cross experiment among populations of four genetic lineages (W1, W2, W3 and E1) of S. nutans from Western Europe and genotyped 560 leaf samples (both green and white leaves for variegated hybrids) using six lineage-specific plastid single nucleotide polymorphisms. KEY RESULTS A high proportion of the surviving hybrids (≤98 %) inherited the paternal plastid genome, indicating paternal leakage. The level of paternal leakage depended on cross type and cross direction. The E1 and W2 lineages as maternal lineages led to the highest hybrid mortality and to the highest paternal leakage from W1 and W3 lineages in the few surviving hybrids. This was consistent with E1 and W2 lineages, which contained the most divergent plastid genomes. When W3 was the mother, more hybrids survived, and no paternal leakage was detected. CONCLUSIONS By providing a plastid genome potentially more compatible with the hybrid nuclear background, paternal leakage has the potential to rescue inter-lineage hybrids from plastid-nuclear incompatibilities. This phenomenon might slow down the speciation process, provided hybrid survival and reproduction can occur in the wild.
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Affiliation(s)
- Zoé Postel
- Univ Lille, CNRS, UMR 8198 – Evo-Eco-Paleo, F-59000 Lille, France
- Department of Ecology, Environment and Plant Sciences, Science for Life Laboratory, Stockholm University, Stockholm, Sweden
| | - Fabienne Van Rossum
- Meise Botanic Garden, Nieuwelaan 38, BE-1860 Meise, Belgium
- Service général de l’Enseignement supérieur et de la Recherche scientifique, Fédération Wallonie Bruxelles, rue A. Lavallée 1, BE-1080 Brussels, Belgium
| | - Cécile Godé
- Univ Lille, CNRS, UMR 8198 – Evo-Eco-Paleo, F-59000 Lille, France
| | - Eric Schmitt
- Univ Lille, CNRS, UMR 8198 – Evo-Eco-Paleo, F-59000 Lille, France
| | - Pascal Touzet
- Univ Lille, CNRS, UMR 8198 – Evo-Eco-Paleo, F-59000 Lille, France
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Thureborn O, Wikström N, Razafimandimbison SG, Rydin C. Phylogenomics and topological conflicts in the tribe Anthospermeae (Rubiaceae). Ecol Evol 2024; 14:e10868. [PMID: 38274863 PMCID: PMC10809029 DOI: 10.1002/ece3.10868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Revised: 11/15/2023] [Accepted: 12/05/2023] [Indexed: 01/27/2024] Open
Abstract
Genome skimming (shallow whole-genome sequencing) offers time- and cost-efficient production of large amounts of DNA data that can be used to address unsolved evolutionary questions. Here we address phylogenetic relationships and topological incongruence in the tribe Anthospermeae (Rubiaceae), using phylogenomic data from the mitochondrion, the nuclear ribosomal cistron, and the plastome. All three genomic compartments resolve relationships in the Anthospermeae; the tribe is monophyletic and consists of three major subclades. Carpacoce Sond. is sister to the remaining clade, which comprises an African subclade and a Pacific subclade. Most results, from all three genomic compartments, are statistically well supported; however, not fully consistent. Intergenomic topological incongruence is most notable in the Pacific subclade but present also in the African subclade. Hybridization and introgression followed by organelle capture may explain these conflicts but other processes, such as incomplete lineage sorting (ILS), can yield similar patterns and cannot be ruled out based on the results. Whereas the null hypothesis of congruence among all sequenced loci in the individual genomes could not be rejected for nuclear and mitochondrial data, it was rejected for plastid data. Phylogenetic analyses of three subsets of plastid loci identified using the hierarchical likelihood ratio test demonstrated statistically supported intragenomic topological incongruence. Given that plastid genes are thought to be fully linked, this result is surprising and may suggest modeling or sampling error. However, biological processes such as biparental inheritance and inter-plastome recombination have been reported and may be responsible for the observed intragenomic incongruence. Mitochondrial insertions into the plastome are rarely documented in angiosperms. Our results indicate that a mitochondrial insertion event in the plastid trnS GGA - rps4 IGS region occurred in the common ancestor of the Pacific clade of Anthospermeae. Exclusion/inclusion of this locus in phylogenetic analyses had a strong impact on topological results in the Pacific clade.
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Affiliation(s)
- Olle Thureborn
- Department of Ecology, Environment and Plant SciencesStockholm UniversityStockholmSweden
| | - Niklas Wikström
- Department of Ecology, Environment and Plant SciencesStockholm UniversityStockholmSweden
- The Bergius FoundationThe Royal Academy of SciencesStockholmSweden
| | | | - Catarina Rydin
- Department of Ecology, Environment and Plant SciencesStockholm UniversityStockholmSweden
- The Bergius FoundationThe Royal Academy of SciencesStockholmSweden
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Broz AK, Sloan DB, Johnston IG. Stochastic organelle genome segregation through Arabidopsis development and reproduction. THE NEW PHYTOLOGIST 2024; 241:896-910. [PMID: 37925790 PMCID: PMC10841260 DOI: 10.1111/nph.19288] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Accepted: 09/07/2023] [Indexed: 11/07/2023]
Abstract
Organelle DNA (oDNA) in mitochondria and plastids is vital for plant (and eukaryotic) life. Selection against damaged oDNA is mediated in part by segregation - sorting different oDNA types into different cells in the germline. Plants segregate oDNA very rapidly, with oDNA recombination protein MSH1 a key driver of this segregation, but we have limited knowledge of the dynamics of this segregation within plants and between generations. Here, we reveal how oDNA evolves through Arabidopsis thaliana development and reproduction. We combine stochastic modelling, Bayesian inference, and model selection with new and existing tissue-specific oDNA measurements from heteroplasmic Arabidopsis plant lines through development and between generations. Segregation proceeds gradually but continually during plant development, with a more rapid increase between inflorescence formation and the next generation. When MSH1 is compromised, the majority of observed segregation can be achieved through partitioning at cell divisions. When MSH1 is functional, mtDNA segregation is far more rapid; we show that increased oDNA gene conversion is a plausible mechanism quantitatively explaining this acceleration. These findings reveal the quantitative, time-dependent details of oDNA segregation in Arabidopsis. We also discuss the support for different models of the plant germline provided by these observations.
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Affiliation(s)
- Amanda K Broz
- Department of Biology, Colorado State University, Fort Collins, CO, 80523, USA
| | - Daniel B Sloan
- Department of Biology, Colorado State University, Fort Collins, CO, 80523, USA
| | - Iain G Johnston
- Department of Mathematics, University of Bergen, Bergen, 5007, Norway
- Computational Biology Unit, University of Bergen, Bergen, 5007, Norway
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Wang M, Yu W, Yang J, Hou Z, Li C, Niu Z, Zhang B, Xue Q, Liu W, Ding X. Mitochondrial genome comparison and phylogenetic analysis of Dendrobium (Orchidaceae) based on whole mitogenomes. BMC PLANT BIOLOGY 2023; 23:586. [PMID: 37993773 PMCID: PMC10666434 DOI: 10.1186/s12870-023-04618-9] [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: 02/21/2023] [Accepted: 11/17/2023] [Indexed: 11/24/2023]
Abstract
BACKGROUND Mitochondrial genomes are essential for deciphering the unique evolutionary history of seed plants. However, the rules of their extreme variation in genomic size, multi-chromosomal structure, and foreign sequences remain unresolved in most plant lineages, which further hindered the application of mitogenomes in phylogenetic analyses. RESULTS Here, we took Dendrobium (Orchidaceae) which shows the great divergence of morphology and difficulty in species taxonomy as the study focus. We first de novo assembled two complete mitogenomes of Dendrobium wilsonii and Dendrobium henanense that were 763,005 bp and 807,551 bp long with multichromosomal structures. To understand the evolution of Dendrobium mitogenomes, we compared them with those of four other orchid species. The results showed great variations of repetitive and chloroplast-derived sequences in Dendrobium mitogenomes. Moreover, the intergenic content of Dendrobium mitogenomes has undergone expansion during evolution. We also newly sequenced mitogenomes of 26 Dendrobium species and reconstructed phylogenetic relationships of Dendrobium based on genomic mitochondrial and plastid data. The results indicated that the existence of chloroplast-derived sequences made the mitochondrial phylogeny display partial characteristics of the plastid phylogeny. Additionally, the mitochondrial phylogeny provided new insights into the phylogenetic relationships of Dendrobium species. CONCLUSIONS Our study revealed the evolution of Dendrobium mitogenomes and the potential of mitogenomes in deciphering phylogenetic relationships at low taxonomic levels.
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Grants
- 32070353 National Natural Science Foundation of China
- 32070353 National Natural Science Foundation of China
- 32070353 National Natural Science Foundation of China
- 32070353 National Natural Science Foundation of China
- 32070353 National Natural Science Foundation of China
- 32070353 National Natural Science Foundation of China
- 32070353 National Natural Science Foundation of China
- 32070353 National Natural Science Foundation of China
- 32070353 National Natural Science Foundation of China
- 32070353 National Natural Science Foundation of China
- LYKJ[2021]12 Forestry independent innovation project of Jiangsu Province, China
- LYKJ[2021]12 Forestry independent innovation project of Jiangsu Province, China
- LYKJ[2021]12 Forestry independent innovation project of Jiangsu Province, China
- LYKJ[2021]12 Forestry independent innovation project of Jiangsu Province, China
- LYKJ[2021]12 Forestry independent innovation project of Jiangsu Province, China
- LYKJ[2021]12 Forestry independent innovation project of Jiangsu Province, China
- LYKJ[2021]12 Forestry independent innovation project of Jiangsu Province, China
- LYKJ[2021]12 Forestry independent innovation project of Jiangsu Province, China
- LYKJ[2021]12 Forestry independent innovation project of Jiangsu Province, China
- LYKJ[2021]12 Forestry independent innovation project of Jiangsu Province, China
- CX (22) 3147 Agricultural independent innovation project of Jiangsu Province, China
- CX (22) 3147 Agricultural independent innovation project of Jiangsu Province, China
- CX (22) 3147 Agricultural independent innovation project of Jiangsu Province, China
- CX (22) 3147 Agricultural independent innovation project of Jiangsu Province, China
- CX (22) 3147 Agricultural independent innovation project of Jiangsu Province, China
- CX (22) 3147 Agricultural independent innovation project of Jiangsu Province, China
- CX (22) 3147 Agricultural independent innovation project of Jiangsu Province, China
- CX (22) 3147 Agricultural independent innovation project of Jiangsu Province, China
- CX (22) 3147 Agricultural independent innovation project of Jiangsu Province, China
- CX (22) 3147 Agricultural independent innovation project of Jiangsu Province, China
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Affiliation(s)
- Mengting Wang
- College of Life Sciences, Nanjing Normal University, Nanjing, China
- Ningbo Key Laboratory of Agricultural Germplasm Resources Mining and Environmental Regulation, College of Science and Technology, Ningbo University, Cixi, China
| | - Wenhui Yu
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Jiapeng Yang
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Zhenyu Hou
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Chao Li
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Zhitao Niu
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Benhou Zhang
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Qingyun Xue
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Wei Liu
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Xiaoyu Ding
- College of Life Sciences, Nanjing Normal University, Nanjing, China.
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Lu G, Wang W, Mao J, Li Q, Que Y. Complete mitogenome assembly of Selenicereus monacanthus revealed its molecular features, genome evolution, and phylogenetic implications. BMC PLANT BIOLOGY 2023; 23:541. [PMID: 37924024 PMCID: PMC10625231 DOI: 10.1186/s12870-023-04529-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Accepted: 10/16/2023] [Indexed: 11/06/2023]
Abstract
BACKGROUND Mitochondria are the powerhouse of the cell and are critical for plant growth and development. Pitaya (Selenicereus or Hylocereus) is the most important economic crop in the family Cactaceae and is grown worldwide, however its mitogenome is unreported. RESULTS This study assembled the complete mitogenome of the red skin and flesh of pitaya (Selenicereus monacanthus). It is a full-length, 2,290,019 bp circular molecule encoding 59 unique genes that only occupy 2.17% of the entire length. In addition, 4,459 pairs of dispersed repeats (≥ 50 bp) were identified, accounting for 84.78% of the total length, and three repeats (394,588, 124,827, and 13,437 bp) mediating genomic recombination were identified by long read mapping and Sanger sequencing. RNA editing events were identified in all 32 protein-coding genes (PCGs), among which four sites (nad1-2, nad4L-2, atp9-copy3-223, and ccmFC-1309) were associated with the initiation or termination of PCGs. Seventy-eight homologous fragments of the chloroplast genome were identified in the mitogenome, the longest having 4,523 bp. In addition, evolutionary analyses suggest that S. monacanthus may have undergone multiple genomic reorganization events during evolution, with the loss of at least nine PCGs (rpl2, rpl10, rps2, rps3, rps10, rps11, rps14, rps19, and sdh3). CONCLUSIONS This study revealed the genetic basis of the S. monacanthus mitogenome, and provided a scientific basis for further research on phenotypic traits and germplasm resource development.
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Affiliation(s)
- Guilong Lu
- College of Horticulture and Landscape Architecture, Henan Institute of Science and Technology, Xinxiang, 453003, China
| | - Wenhua Wang
- Institute of Vegetables, Tibet Academy of Agricultural and Animal Husbandry Sciences, Lhasa, 890032, China
| | - Juan Mao
- Institute of Vegetables, Tibet Academy of Agricultural and Animal Husbandry Sciences, Lhasa, 890032, China
| | - Qing Li
- Institute of Vegetables, Tibet Academy of Agricultural and Animal Husbandry Sciences, Lhasa, 890032, China.
| | - Youxiong Que
- College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
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Cao Y, Yin D, Pang B, Li H, Liu Q, Zhai Y, Ma N, Shen H, Jia Q, Wang D. Assembly and phylogenetic analysis of the mitochondrial genome of endangered medicinal plant Huperzia crispata. Funct Integr Genomics 2023; 23:295. [PMID: 37691055 DOI: 10.1007/s10142-023-01223-9] [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: 04/19/2023] [Revised: 08/08/2023] [Accepted: 08/28/2023] [Indexed: 09/12/2023]
Abstract
Huperzia crispata is a traditional Chinese herb plant and has attracted special attention in recent years for its products Hup A can serve as an acetylcholinesterase inhibitor (AChEI). Although the chloroplast (cp) genome of H. crispata has been studied, there are no reports regarding the Huperzia mitochondrial (mt) genome since the previously reported H. squarrosa has been revised as Phlegmariurus squarrosus. The mt genome of H. crispata was sequenced using a combination of long-read nanopore and Illumina sequencing platforms. The entire H. crispata mt genome was assembled in a circular with a length of 412,594 bp and a total of 91 genes, including 45 tRNAs, 6 rRNAs, 37 protein-coding genes (PCGs), and 3 pseudogenes. Notably, the rps8 gene was present in P. squarrosus and a pseudogene rps8 was presented in H. crispata, which was lacking in most of Pteridophyta and Gymnospermae. Intron-encoded maturase (mat-atp9i85 and mat-cobi787) genes were present in H. crispata and P. squarrosus, but lost in other examined lycophytes, ferns, and Gymnospermae plants. Collinearity analysis showed that the mt genome of H. crispata and P. squarrossus is highly conservative compared to other ferns. Relative synonymous codon usage (RSCU) analysis showed that the amino acids most frequently found were phenylalanine (Phe) (4.77%), isoleucine (Ile) (4.71%), lysine (Lys) (4.26%), while arginine (Arg) (0.32%), and histidine (His) (0.42%) were rarely found. Simple sequence repeats (SSR) analysis revealed that a total of 114 SSRs were identified in the mt genome of H. crispata and account for 0.35% of the whole mt genome. Monomer repeats were the majority types of SSRs and represent 91.89% of the total SSRs. In addition, a total of 1948 interspersed repeats (158 forward, 147 palindromic, and 5 reverse repeats) with a length ranging from 30 bp to 14,945 bp were identified in the H. crispata mt genome and the 30-39-bp repeats were the most abundant type. Gene transfer analysis indicated that a total of 12 homologous fragments were discovered between the cp and mt genomes of H. crispata, accounting for 0.93% and 2.48% of the total cp and mt genomes, respectively. The phylogenetic trees revealed that H. crispata was the sister of P. squarrosus. The Ka/Ks analysis results suggested that most PCGs, except atp6 gene, were subject to purification selection during evolution. Our study provides extensive information on the features of the H. crispata mt genome and will help unravel evolutionary relationships, and molecular identification within lycophytes.
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Affiliation(s)
- Yu Cao
- Key Laboratory of Plant Secondary Metabolism Regulation in Zhejiang Province, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Zhejiang, 310018, Hangzhou, China
| | - Dengpan Yin
- Key Laboratory of Plant Secondary Metabolism Regulation in Zhejiang Province, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Zhejiang, 310018, Hangzhou, China
| | - Bo Pang
- Key Laboratory of Plant Secondary Metabolism Regulation in Zhejiang Province, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Zhejiang, 310018, Hangzhou, China
| | - Haibo Li
- Yuyao Seedling Management Station, Ningbo, Zhejiang, 315400, China
| | - Qiao Liu
- Key Laboratory of Plant Secondary Metabolism Regulation in Zhejiang Province, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Zhejiang, 310018, Hangzhou, China
| | - Yufeng Zhai
- Key Laboratory of Plant Secondary Metabolism Regulation in Zhejiang Province, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Zhejiang, 310018, Hangzhou, China
| | - Nan Ma
- Key Laboratory of Plant Secondary Metabolism Regulation in Zhejiang Province, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Zhejiang, 310018, Hangzhou, China
| | - Hongjun Shen
- Ningbo Delai Medicinal Material Planting Co, Ltd, 315444, Ningbo, Zhejiang, 315444, China
| | - Qiaojun Jia
- Key Laboratory of Plant Secondary Metabolism Regulation in Zhejiang Province, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Zhejiang, 310018, Hangzhou, China
| | - Dekai Wang
- Key Laboratory of Plant Secondary Metabolism Regulation in Zhejiang Province, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Zhejiang, 310018, Hangzhou, China.
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Taniguchi E, Satoh K, Ohkubo M, Ue S, Matsuhira H, Kuroda Y, Kubo T, Kitazaki K. Nuclear DNA segments homologous to mitochondrial DNA are obstacles for detecting heteroplasmy in sugar beet (Beta vulgaris L.). PLoS One 2023; 18:e0285430. [PMID: 37552681 PMCID: PMC10409277 DOI: 10.1371/journal.pone.0285430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 04/21/2023] [Indexed: 08/10/2023] Open
Abstract
Heteroplasmy, the coexistence of multiple mitochondrial DNA (mtDNA) sequences in a cell, is well documented in plants. Next-generation sequencing technology (NGS) has made it feasible to sequence entire genomes. Thus, NGS has the potential to detect heteroplasmy; however, the methods and pitfalls in heteroplasmy detection have not been fully investigated and identified. One obstacle for heteroplasmy detection is the sequence homology between mitochondrial-, plastid-, and nuclear DNA, of which the influence of nuclear DNA segments homologous to mtDNA (numt) need to be minimized. To detect heteroplasmy, we first excluded nuclear DNA sequences of sugar beet (Beta vulgaris) line EL10 from the sugar beet mtDNA sequence. NGS reads were obtained from single plants of sugar beet lines NK-195BRmm-O and NK-291BRmm-O and mapped to the unexcluded mtDNA regions. More than 1000 sites exhibited intra-individual polymorphism as detected by genome browsing analysis. We focused on a 309-bp region where 12 intra-individual polymorphic sites were closely linked to each other. Although the existence of DNA molecules having variant alleles at the 12 sites was confirmed by PCR amplification from NK-195BRmm-O and NK-291BRmm-O, these variants were not always called by six variant-calling programs, suggesting that these programs are inappropriate for intra-individual polymorphism detection. When we changed the nuclear DNA reference, a numt absent from EL10 was found to include the 309-bp region. Genetic segregation of an F2 population from NK-195BRmm-O x NK-291BRmm-O supported the numt origin of the variant alleles. Using four references, we found that numt detection exhibited reference dependency, and extreme polymorphism of numts exists among sugar beet lines. One of the identified numts absent from EL10 is also associated with another intra-individual polymorphic site in NK-195mm-O. Our data suggest that polymorphism among numts is unexpectedly high within sugar beets, leading to confusion about the true degree of heteroplasmy.
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Affiliation(s)
- Eigo Taniguchi
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Kosuke Satoh
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Megumi Ohkubo
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Sachiyo Ue
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Hiroaki Matsuhira
- Hokkaido Agricultural Research Center, National Agriculture and Food Research Organization, Memuro, Hokkaido, Japan
| | - Yosuke Kuroda
- Hokkaido Agricultural Research Center, National Agriculture and Food Research Organization, Memuro, Hokkaido, Japan
| | - Tomohiko Kubo
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Kazuyoshi Kitazaki
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan
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11
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Xu S, Teng K, Zhang H, Wu J, Duan L, Zhang H, Wen H, Teng W, Yue Y, Fan X. The first complete mitochondrial genome of Carex (C. breviculmis): a significantly expanded genome with highly structural variations. PLANTA 2023; 258:43. [PMID: 37450262 DOI: 10.1007/s00425-023-04169-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 05/27/2023] [Indexed: 07/18/2023]
Abstract
MAIN CONCLUSION The first complete mitochondrial genome of Carex (C. breviculmis) was sequenced and assembled, and its genomic signature was analyzed and the possible conformations of its mitochondrial genome were validated. Carex breviculmis is a very adaptable grass that is highly resistant to environmental stresses such as drought and low light. It is also admired as a landscape plant with high development prospects and scientific research value. In this study, the mitochondrial genome of C. breviculmis was assembled using Pacbio and Illumina sequencing data. We detected 267 pairs of repeats and found that three pairs of repeats could mediate the recombination of its mitochondrial genome and formed four possible conformations, of which we verified the two conformations mediated by the shortest pair of repeats using PCR amplification and Sanger sequencing. The major conformation of the C. breviculmis mitochondrial genome is a 1,414,795 bp long circular molecule with 33 annotated protein-coding genes, 15 tRNA genes, and three rRNA genes. We detected a total of 25 homologous sequences between the chloroplast and mitochondrial genomes, corresponding to 0.40% of the mitochondrial genome. Combined with the low GC content (41.24%), we conclude that the reduction in RNA editing sites in the C. breviculmis mitochondrial genome may be due to an accumulation of point mutations in C-to-T or retroprocessing events within the genome. The relatively low number of RNA editing sites in its mitochondrial genome could serve as important material for subsequent studies on the selection pressure of RNA editing in angiosperms. A maximum likelihood analysis based on 23 conserved mitochondrial genes from 28 species reflects an accurate evolutionary and taxonomic position of C. breviculmis. This research provided us with a comprehensive understanding of the mitochondrial genome of Carex and also provided important information for its molecular breeding.
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Affiliation(s)
- Shenjian Xu
- Institute of Grassland, Flowers, and Ecology, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
| | - Ke Teng
- Institute of Grassland, Flowers, and Ecology, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
| | - Hui Zhang
- Institute of Grassland, Flowers, and Ecology, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
| | - Juying Wu
- Institute of Grassland, Flowers, and Ecology, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
| | - Liusheng Duan
- College of Plants and Technology, Beijing University of Agriculture, Beijing, China
| | - Hongyu Zhang
- Institute of Grassland, Flowers, and Ecology, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
| | - Haifeng Wen
- Institute of Grassland, Flowers, and Ecology, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
| | - Wenjun Teng
- Institute of Grassland, Flowers, and Ecology, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
| | - Yuesen Yue
- Institute of Grassland, Flowers, and Ecology, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China.
| | - Xifeng Fan
- Institute of Grassland, Flowers, and Ecology, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China.
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12
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Makarenko MS, Azarin KV, Gavrilova VA. Mitogenomic Research of Silverleaf Sunflower ( Helianthus argophyllus) and Its Interspecific Hybrids. Curr Issues Mol Biol 2023; 45:4841-4849. [PMID: 37367057 DOI: 10.3390/cimb45060308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 05/28/2023] [Accepted: 05/30/2023] [Indexed: 06/28/2023] Open
Abstract
Interspecific hybridization is widespread for sunflowers, both in wild populations and commercial breeding. One of the most common species that can efficiently cross with Helianthus annuus is the Silverleaf sunflower-Helianthus argophyllus. The current study carried out structural and functional organization analyses of mitochondrial DNA in H. argophyllus and the interspecific hybrid, H. annuus (VIR114A line) × H. argophyllus. The complete mitogenome of H. argophyllus counts 300,843 bp, has a similar organization to the mitogenome of cultivated sunflower, and holds SNPs typical for wild sunflowers. RNA editing analysis predicted 484 sites in H. argophyllus mitochondrial CDS. The mitochondrial genome of the H. annuus × H. argophyllus hybrid is identical to the maternal line (VIR114A). We expected that significant rearrangements in the mitochondrial DNA of the hybrid would occur, due to the frequent recombination. However, the hybrid mitogenome lacks rearrangements, presumably due to the preservation of nuclear-cytoplasmic interaction paths.
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Affiliation(s)
- Maksim S Makarenko
- The Laboratory of Plant Genomics, The Institute for Information Transmission Problems, 127051 Moscow, Russia
| | - Kirill V Azarin
- The Laboratory of Molecular Genetics, Southern Federal University, 344006 Rostov-on-Don, Russia
| | - Vera A Gavrilova
- Oil and Fiber Crops Genetic Resources Department, The N.I. Vavilov All Russian Institute of Plant Genetic Resources, 190031 Saint Petersburg, Russia
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13
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Cao P, Huang Y, Zong M, Xu Z. De Novo Assembly and Comparative Analysis of the Complete Mitochondrial Genome of Chaenomeles speciosa (Sweet) Nakai Revealed the Existence of Two Structural Isomers. Genes (Basel) 2023; 14:526. [PMID: 36833452 PMCID: PMC9957484 DOI: 10.3390/genes14020526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 02/01/2023] [Accepted: 02/17/2023] [Indexed: 02/22/2023] Open
Abstract
As a valuable Chinese traditional medicinal species, Chaenomeles speciosa (Sweet) Nakai (C. speciosa) is a natural resource with significant economic and ornamental value. However, its genetic information is not well understood. In this study, the complete mitochondrial genome of C. speciosa was assembled and characterized to explore the repeat sequences, recombination events, rearrangements, and IGT, to predict RNA editing sites, and to clarify the phylogenetic and evolutionary relationship. The C. speciosa mitochondrial genome was found to have two circular chromosomes as its major conformation, with a total length of 436,464 bp and 45.2% GC content. The mitochondrial genome contained 54 genes, including 33 unique protein-coding genes, 18 tRNAs, and 3 rRNA genes. Seven pairs of repeat sequences involving recombination events were analyzed. Both the repeat pairs, R1 and R2, played significant roles in mediating the major and minor conformations. In total, 18 MTPTs were identified, 6 of which were complete tRNA genes. There were 454 RNA editing sites in the 33 protein-coding sequences predicted by the PREPACT3 program. A phylogenetic analysis based on 22 species of mitochondrial genomes was constructed and indicated highly conserved PCG sequences. Synteny analyses showed extensive genomic rearrangements in the mitochondrial genome of C. speciosa and closely related species. This work is the first to report the C. speciosa mitochondrial genome, which is of great significance for conducting additional genetic studies on this organism.
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Affiliation(s)
- Pei Cao
- Institute of Sericulture and Tea, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Yuan Huang
- Institute of Sericulture and Tea, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Mei Zong
- College of Life Sciences, Anqing Normal University, Anqing 246133, China
| | - Zilong Xu
- Institute of Sericulture and Tea, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
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14
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Zhang S, Wang J, He W, Kan S, Liao X, Jordan DR, Mace ES, Tao Y, Cruickshank AW, Klein R, Yuan D, Tembrock LR, Wu Z. Variation in mitogenome structural conformation in wild and cultivated lineages of sorghum corresponds with domestication history and plastome evolution. BMC PLANT BIOLOGY 2023; 23:91. [PMID: 36782130 PMCID: PMC9926791 DOI: 10.1186/s12870-023-04104-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 02/06/2023] [Indexed: 06/18/2023]
Abstract
BACKGROUND Mitochondria are organelles within eukaryotic cells that are central to the metabolic processes of cellular respiration and ATP production. However, the evolution of mitochondrial genomes (mitogenomes) in plants is virtually unknown compared to animal mitogenomes or plant plastids, due to complex structural variation and long stretches of repetitive DNA making accurate genome assembly more challenging. Comparing the structural and sequence differences of organellar genomes within and between sorghum species is an essential step in understanding evolutionary processes such as organellar sequence transfer to the nuclear genome as well as improving agronomic traits in sorghum related to cellular metabolism. RESULTS Here, we assembled seven sorghum mitochondrial and plastid genomes and resolved reticulated mitogenome structures with multilinked relationships that could be grouped into three structural conformations that differ in the content of repeats and genes by contig. The grouping of these mitogenome structural types reflects the two domestication events for sorghum in east and west Africa. CONCLUSIONS We report seven mitogenomes of sorghum from different cultivars and wild sources. The assembly method used here will be helpful in resolving complex genomic structures in other plant species. Our findings give new insights into the structure of sorghum mitogenomes that provides an important foundation for future research into the improvement of sorghum traits related to cellular respiration, cytonuclear incompatibly, and disease resistance.
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Affiliation(s)
- Shuo Zhang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Hubei, Wuhan, 430070, China
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Guangdong, Shenzhen, 518120, China
| | - Jie Wang
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Guangdong, Shenzhen, 518120, China
| | - Wenchuang He
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Guangdong, Shenzhen, 518120, China
| | - Shenglong Kan
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Guangdong, Shenzhen, 518120, China
| | - Xuezhu Liao
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Guangdong, Shenzhen, 518120, China
| | - David R Jordan
- Queensland Alliance for Agriculture and Food Innovation (QAAFI), Hermitage Research Facility, The University of Queensland, Warwick, Queensland, 4370, Australia
| | - Emma S Mace
- Queensland Alliance for Agriculture and Food Innovation (QAAFI), Hermitage Research Facility, The University of Queensland, Warwick, Queensland, 4370, Australia
| | - Yongfu Tao
- Queensland Alliance for Agriculture and Food Innovation (QAAFI), Hermitage Research Facility, The University of Queensland, Warwick, Queensland, 4370, Australia
| | - Alan W Cruickshank
- Department of Agriculture and Fisheries (DAF), Agri-Science Queensland, Hermitage Research Facility, Warwick, Queensland, 4370, Australia
| | - Robert Klein
- Southern Plains Agricultural Research Center, USDA-ARS, College Station, Texas, 77845, USA
| | - Daojun Yuan
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Hubei, Wuhan, 430070, China
| | - Luke R Tembrock
- Department of Agricultural Biology, Colorado State University, Fort Collins, Colorado, 80523, USA.
| | - Zhiqiang Wu
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Guangdong, Shenzhen, 518120, China.
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15
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Radzvilavicius AL, Johnston IG. Organelle bottlenecks facilitate evolvability by traversing heteroplasmic fitness valleys. Front Genet 2022; 13:974472. [PMID: 36386853 PMCID: PMC9650085 DOI: 10.3389/fgene.2022.974472] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 10/11/2022] [Indexed: 07/09/2024] Open
Abstract
Bioenergetic organelles-mitochondria and plastids-retain their own genomes (mtDNA and ptDNA), and these organelle DNA (oDNA) molecules are vital for eukaryotic life. Like all genomes, oDNA must be able to evolve to suit new environmental challenges. However, mixed oDNA populations in cells can challenge cellular bioenergetics, providing a penalty to the appearance and adaptation of new mutations. Here we show that organelle "bottlenecks," mechanisms increasing cell-to-cell oDNA variability during development, can overcome this mixture penalty and facilitate the adaptation of beneficial mutations. We show that oDNA heteroplasmy and bottlenecks naturally emerge in evolutionary simulations subjected to fluctuating environments, demonstrating that this evolvability is itself evolvable. Usually thought of as a mechanism to clear damaging mutations, organelle bottlenecks therefore also resolve the tension between intracellular selection for pure cellular oDNA populations and the "bet-hedging" need for evolvability and adaptation to new environments. This general theory suggests a reason for the maintenance of organelle heteroplasmy in cells, and may explain some of the observed diversity in organelle maintenance and inheritance across taxa.
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Affiliation(s)
- Arunas L. Radzvilavicius
- Department of Mathematics, University of Bergen, Bergen, Norway
- Computational Biology Unit, University of Bergen, Bergen, Norway
| | - Iain G. Johnston
- Department of Mathematics, University of Bergen, Bergen, Norway
- Computational Biology Unit, University of Bergen, Bergen, Norway
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16
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Pan-mitogenomics reveals the genetic basis of cytonuclear conflicts in citrus hybridization, domestication, and diversification. Proc Natl Acad Sci U S A 2022; 119:e2206076119. [PMID: 36260744 PMCID: PMC9618123 DOI: 10.1073/pnas.2206076119] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Although interactions between the cytoplasmic and nuclear genomes occurred during diversification of many plants, the evolutionary conflicts due to cytonuclear interactions are poorly understood in crop breeding. Here, we constructed a pan-mitogenome and identified chimeric open reading frames (ORFs) generated by extensive structural variations (SVs). Meanwhile, short reads from 184 accessions of citrus species were combined to construct three variation maps for the nuclear, mitochondrial, and chloroplast genomes. The population genomic data showed discordant topologies between the cytoplasmic and nuclear genomes because of differences in mutation rates and levels of heteroplasmy from paternal leakage. An analysis of species-specific SVs indicated that mitochondrial heteroplasmy was common and that chloroplast heteroplasmy was undetectable. Interestingly, we found a prominent divergence in the mitogenomes and the highest genetic load in the, which may provide the basis for cytoplasmic male sterility (CMS) and thus influence the reshuffling of the cytoplasmic and nuclear genomes during hybridization. Using cytoplasmic replacement experiments, we identified a type of species-specific CMS in mandarin related to two chimeric mitochondrial genes. Our analyses indicate that cytoplasmic genomes from mandarin have rarely been maintained in hybrids and that paternal leakage produced very low levels of mitochondrial heteroplasmy in mandarin. A genome-wide association study (GWAS) provided evidence for three nuclear genes that encode pentatricopeptide repeat (PPR) proteins contributing to the cytonuclear interactions in the Citrus genus. Our study demonstrates the occurrence of evolutionary conflicts between cytoplasmic and nuclear genomes in citrus and has important implications for genetics and breeding.
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17
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Broz AK, Keene A, Fernandes Gyorfy M, Hodous M, Johnston IG, Sloan DB. Sorting of mitochondrial and plastid heteroplasmy in Arabidopsis is extremely rapid and depends on MSH1 activity. Proc Natl Acad Sci U S A 2022; 119:e2206973119. [PMID: 35969753 PMCID: PMC9407294 DOI: 10.1073/pnas.2206973119] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 07/11/2022] [Indexed: 12/16/2022] Open
Abstract
The fate of new mitochondrial and plastid mutations depends on their ability to persist and spread among the numerous organellar genome copies within a cell (heteroplasmy). The extent to which heteroplasmies are transmitted across generations or eliminated through genetic bottlenecks is not well understood in plants, in part because their low mutation rates make these variants so infrequent. Disruption of MutS Homolog 1 (MSH1), a gene involved in plant organellar DNA repair, results in numerous de novo point mutations, which we used to quantitatively track the inheritance of single nucleotide variants in mitochondrial and plastid genomes in Arabidopsis. We found that heteroplasmic sorting (the fixation or loss of a variant) was rapid for both organelles, greatly exceeding rates observed in animals. In msh1 mutants, plastid variants sorted faster than those in mitochondria and were typically fixed or lost within a single generation. Effective transmission bottleneck sizes (N) for plastids and mitochondria were N ∼ 1 and 4, respectively. Restoring MSH1 function further increased the rate of heteroplasmic sorting in mitochondria (N ∼ 1.3), potentially because of its hypothesized role in promoting gene conversion as a mechanism of DNA repair, which is expected to homogenize genome copies within a cell. Heteroplasmic sorting also favored GC base pairs. Therefore, recombinational repair and gene conversion in plant organellar genomes can potentially accelerate the elimination of heteroplasmies and bias the outcome of this sorting process.
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Affiliation(s)
- Amanda K. Broz
- Department of Biology, Colorado State University, Fort Collins, CO 80523
| | - Alexandra Keene
- Department of Biology, Colorado State University, Fort Collins, CO 80523
| | | | - Mychaela Hodous
- Department of Biology, Colorado State University, Fort Collins, CO 80523
| | - Iain G. Johnston
- Department of Mathematics, University of Bergen, Bergen, 5007, Norway
- Computational Biology Unit, University of Bergen, Bergen, 5007, Norway
| | - Daniel B. Sloan
- Department of Biology, Colorado State University, Fort Collins, CO 80523
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18
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Tarasenko TA, Koulintchenko MV. Heterogeneity of the Mitochondrial Population in Cells of Plants and Other Organisms. Mol Biol 2022. [DOI: 10.1134/s0026893322020157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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19
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Breton S, Stewart DT, Brémaud J, Havird JC, Smith CH, Hoeh WR. Did doubly uniparental inheritance (DUI) of mtDNA originate as a cytoplasmic male sterility (CMS) system? Bioessays 2022; 44:e2100283. [PMID: 35170770 PMCID: PMC9083018 DOI: 10.1002/bies.202100283] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 01/26/2022] [Accepted: 01/31/2022] [Indexed: 01/10/2023]
Abstract
Animal and plant species exhibit an astonishing diversity of sexual systems, including environmental and genetic determinants of sex, with the latter including genetic material in the mitochondrial genome. In several hermaphroditic plants for example, sex is determined by an interaction between mitochondrial cytoplasmic male sterility (CMS) genes and nuclear restorer genes. Specifically, CMS involves aberrant mitochondrial genes that prevent pollen development and specific nuclear genes that restore it, leading to a mixture of female (male-sterile) and hermaphroditic individuals in the population (gynodioecy). Such a mitochondrial-nuclear sex determination system is thought to be rare outside plants. Here, we present one possible case of CMS in animals. We hypothesize that the only exception to the strict maternal mtDNA inheritance in animals, the doubly uniparental inheritance (DUI) system in bivalves, might have originated as a mitochondrial-nuclear sex-determination system. We document and explore similarities that exist between DUI and CMS, and we propose various ways to test our hypothesis.
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Affiliation(s)
- Sophie Breton
- Département des sciences biologiques, Université de Montréal, Montréal, Québec, Canada
| | - Donald T Stewart
- Department of Biology, Acadia University, Wolfville, Nova Scotia, Canada
| | - Julie Brémaud
- Département des sciences biologiques, Université de Montréal, Montréal, Québec, Canada
| | - Justin C Havird
- Department of Integrative Biology, The University of Texas at Austin, Austin, Texas, USA
| | - Chase H Smith
- Department of Integrative Biology, The University of Texas at Austin, Austin, Texas, USA
| | - Walter R Hoeh
- Department of Biological Sciences, Kent State University, Kent, Ohio, USA
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20
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Pouchon C, Boyer F, Roquet C, Denoeud F, Chave J, Coissac E, Alsos IG, Lavergne S. ORTHOSKIM: in silico sequence capture from genomic and transcriptomic libraries for phylogenomic and barcoding applications. Mol Ecol Resour 2022; 22:2018-2037. [PMID: 35015377 DOI: 10.1111/1755-0998.13584] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Revised: 12/08/2021] [Accepted: 01/05/2022] [Indexed: 11/29/2022]
Abstract
Low-coverage whole genome shotgun sequencing (or genome skimming) has emerged as a cost-effective method for acquiring genomic data in non-model organisms. This method provides sequence information on chloroplast genome (cpDNA), mitochondrial genome (mtDNA) and nuclear ribosomal regions (rDNA), which are over-represented within cells. However, numerous bioinformatic challenges remain to accurately and rapidly obtain such data in organisms with complex genomic structures and rearrangements, in particular for mtDNA in plants or for cpDNA in some plant families. Here we introduce the pipeline ORTHOSKIM, which performs in silico capture of targeted sequences from genomic and transcriptomic libraries without assembling whole organelle genomes. ORTHOSKIM proceeds in three steps: 1) global sequence assembly, 2) mapping against reference sequences, and 3) target sequence extraction; importantly it also includes a range of quality control tests. Different modes are implemented to capture both coding and non-coding regions of cpDNA, mtDNA and rDNA sequences, along with predefined nuclear sequences (e.g. ultra-conserved elements) or collections of single-copy ortholog genes. Moreover, aligned DNA matrices are produced for phylogenetic reconstructions, by performing multiple alignments of the captured sequences. While ORTHOSKIM is suitable for any eukaryote, a case study is presented here, using 114 genome-skimming libraries and 4 RNAseq libraries obtained for two plant families, Primulaceae and Ericaceae, the latter being a well-known problematic family for cpDNA assemblies. ORTHOSKIM recovered with high success rates cpDNA, mtDNA and rDNA sequences, well suited to accurately infer evolutionary relationships within these families. ORTHOSKIM is released under a GPL-3 license and is available at: https://github.com/cpouchon/ORTHOSKIM.
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Affiliation(s)
- Charles Pouchon
- Univ. Grenoble Alpes, CNRS, Univ. Savoie Mont Blanc, LECA, Laboratoire d'Ecologie Alpine (LECA), 38000, Grenoble, France
| | - Frédéric Boyer
- Univ. Grenoble Alpes, CNRS, Univ. Savoie Mont Blanc, LECA, Laboratoire d'Ecologie Alpine (LECA), 38000, Grenoble, France
| | - Cristina Roquet
- Univ. Grenoble Alpes, CNRS, Univ. Savoie Mont Blanc, LECA, Laboratoire d'Ecologie Alpine (LECA), 38000, Grenoble, France.,Systematics and Evolution of Vascular Plants (UAB) - Associated Unit to CSIC, Departament de Biologia Animal, Biologia Vegetal i Ecologia, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain
| | - France Denoeud
- Génomique Métabolique, Genoscope, Institut François Jacob, CEA, CNRS, Univ Evry, Université Paris-Saclay, 2 rue Gaston Crémieux, 91057, Evry, France
| | - Jérome Chave
- Laboratoire Évolution et Diversité Biologique (EDB), UMR CNRS-IRD-UPS 5174, 31062, Toulouse Cedex, France
| | - Eric Coissac
- Univ. Grenoble Alpes, CNRS, Univ. Savoie Mont Blanc, LECA, Laboratoire d'Ecologie Alpine (LECA), 38000, Grenoble, France
| | - Inger Greve Alsos
- The Arctic University Museum of Norway, UiT - The Arctic University of Norway, NO-9037, Tromsø, Norway
| | | | | | - Sébastien Lavergne
- Univ. Grenoble Alpes, CNRS, Univ. Savoie Mont Blanc, LECA, Laboratoire d'Ecologie Alpine (LECA), 38000, Grenoble, France
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21
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Allison TM, Radzvilavicius AL, Dowling DK. Selection for biparental inheritance of mitochondria under hybridization and mitonuclear fitness interactions. Proc Biol Sci 2021; 288:20211600. [PMID: 34875196 PMCID: PMC8651416 DOI: 10.1098/rspb.2021.1600] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Uniparental inheritance (UPI) of mitochondria predominates over biparental inheritance (BPI) in most eukaryotes. However, examples of BPI of mitochondria, or paternal leakage, are becoming increasingly prevalent. Most reported cases of BPI occur in hybrids of distantly related sub-populations. It is thought that BPI in these cases is maladaptive; caused by a failure of female or zygotic autophagy machinery to recognize divergent male-mitochondrial DNA ‘tags’. Yet recent theory has put forward examples in which BPI can evolve under adaptive selection, and empirical studies across numerous metazoan taxa have demonstrated outbreeding depression in hybrids attributable to disruption of population-specific mitochondrial and nuclear genotypes (mitonuclear mismatch). Based on these developments, we hypothesize that BPI may be favoured by selection in hybridizing populations when fitness is shaped by mitonuclear interactions. We test this idea using a deterministic, simulation-based population genetic model and demonstrate that BPI is favoured over strict UPI under moderate levels of gene flow typical of hybridizing populations. Our model suggests that BPI may be stable, rather than a transient phenomenon, in hybridizing populations.
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Affiliation(s)
- Tom M Allison
- School of Biological Sciences, Monash University, Victoria, Australia
| | | | - Damian K Dowling
- School of Biological Sciences, Monash University, Victoria, Australia
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22
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Mandel JR, Ramsey AJ, Holley JM, Scott VA, Mody D, Abbot P. Disentangling Complex Inheritance Patterns of Plant Organellar Genomes: An Example From Carrot. J Hered 2021; 111:531-538. [PMID: 32886780 DOI: 10.1093/jhered/esaa037] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 08/31/2020] [Indexed: 01/05/2023] Open
Abstract
Plant mitochondria and plastids display an array of inheritance patterns and varying levels of heteroplasmy, where individuals harbor more than 1 version of a mitochondrial or plastid genome. Organelle inheritance in plants has the potential to be quite complex and can vary with plant growth, development, and reproduction. Few studies have sought to investigate these complicated patterns of within-individual variation and inheritance using experimental crosses in plants. We carried out crosses in carrot, Daucus carota L. (Apiaceae), which has previously been shown to exhibit organellar heteroplasmy. We used mitochondrial and plastid markers to begin to disentangle the patterns of organellar inheritance and the fate of heteroplasmic variation, with special focus on cases where the mother displayed heteroplasmy. We also investigated heteroplasmy across the plant, assaying leaf samples at different development stages and ages. Mitochondrial and plastid paternal leakage was rare and offspring received remarkably similar heteroplasmic mixtures to their heteroplasmic mothers, indicating that heteroplasmy is maintained over the course of maternal inheritance. When offspring did differ from their mother, they were likely to exhibit a loss of the genetic variation that was present in their mother. Finally, we found that mitochondrial variation did not vary significantly over plant development, indicating that substantial vegetative sorting did not occur. Our study is one of the first to quantitatively investigate inheritance patterns and heteroplasmy in plants using controlled crosses, and we look forward to future studies making use of whole genome information to study the complex evolutionary dynamics of plant organellar genomes.
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Affiliation(s)
- Jennifer R Mandel
- Department of Biological Sciences, The University of Memphis, Memphis, TN, USA.,Center for Biodiversity Research, The University of Memphis, Memphis, TN, USA
| | - Adam J Ramsey
- Department of Biological Sciences, The University of Memphis, Memphis, TN, USA
| | - Jacob M Holley
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Victoria A Scott
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Dviti Mody
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Patrick Abbot
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
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23
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Mitochondrial Genomic Landscape: A Portrait of the Mitochondrial Genome 40 Years after the First Complete Sequence. Life (Basel) 2021; 11:life11070663. [PMID: 34357035 PMCID: PMC8303319 DOI: 10.3390/life11070663] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/02/2021] [Accepted: 07/03/2021] [Indexed: 12/11/2022] Open
Abstract
Notwithstanding the initial claims of general conservation, mitochondrial genomes are a largely heterogeneous set of organellar chromosomes which displays a bewildering diversity in terms of structure, architecture, gene content, and functionality. The mitochondrial genome is typically described as a single chromosome, yet many examples of multipartite genomes have been found (for example, among sponges and diplonemeans); the mitochondrial genome is typically depicted as circular, yet many linear genomes are known (for example, among jellyfish, alveolates, and apicomplexans); the chromosome is normally said to be “small”, yet there is a huge variation between the smallest and the largest known genomes (found, for example, in ctenophores and vascular plants, respectively); even the gene content is highly unconserved, ranging from the 13 oxidative phosphorylation-related enzymatic subunits encoded by animal mitochondria to the wider set of mitochondrial genes found in jakobids. In the present paper, we compile and describe a large database of 27,873 mitochondrial genomes currently available in GenBank, encompassing the whole eukaryotic domain. We discuss the major features of mitochondrial molecular diversity, with special reference to nucleotide composition and compositional biases; moreover, the database is made publicly available for future analyses on the MoZoo Lab GitHub page.
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24
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Broz AK, Waneka G, Wu Z, Fernandes Gyorfy M, Sloan DB. Detecting de novo mitochondrial mutations in angiosperms with highly divergent evolutionary rates. Genetics 2021; 218:iyab039. [PMID: 33704433 PMCID: PMC8128415 DOI: 10.1093/genetics/iyab039] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 03/04/2021] [Indexed: 02/06/2023] Open
Abstract
Although plant mitochondrial genomes typically show low rates of sequence evolution, levels of divergence in certain angiosperm lineages suggest anomalously high mitochondrial mutation rates. However, de novo mutations have never been directly analyzed in such lineages. Recent advances in high-fidelity DNA sequencing technologies have enabled detection of mitochondrial mutations when still present at low heteroplasmic frequencies. To date, these approaches have only been performed on a single plant species (Arabidopsis thaliana). Here, we apply a high-fidelity technique (Duplex Sequencing) to multiple angiosperms from the genus Silene, which exhibits extreme heterogeneity in rates of mitochondrial sequence evolution among close relatives. Consistent with phylogenetic evidence, we found that Silene latifolia maintains low mitochondrial variant frequencies that are comparable with previous measurements in Arabidopsis. Silene noctiflora also exhibited low variant frequencies despite high levels of historical sequence divergence, which supports other lines of evidence that this species has reverted to lower mitochondrial mutation rates after a past episode of acceleration. In contrast, S. conica showed much higher variant frequencies in mitochondrial (but not in plastid) DNA, consistent with an ongoing bout of elevated mitochondrial mutation rates. Moreover, we found an altered mutational spectrum in S. conica heavily biased towards AT→GC transitions. We also observed an unusually low number of mitochondrial genome copies per cell in S. conica, potentially pointing to reduced opportunities for homologous recombination to accurately repair mismatches in this species. Overall, these results suggest that historical fluctuations in mutation rates are driving extreme variation in rates of plant mitochondrial sequence evolution.
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Affiliation(s)
- Amanda K Broz
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Gus Waneka
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Zhiqiang Wu
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, 518120 Shenzhen, China
| | | | - Daniel B Sloan
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA
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Singh S, Bhatia R, Kumar R, Behera TK, Kumari K, Pramanik A, Ghemeray H, Sharma K, Bhattacharya RC, Dey SS. Elucidating Mitochondrial DNA Markers of Ogura-Based CMS Lines in Indian Cauliflowers ( Brassica oleracea var. botrytis L.) and Their Floral Abnormalities Due to Diversity in Cytonuclear Interactions. FRONTIERS IN PLANT SCIENCE 2021; 12:631489. [PMID: 33995434 PMCID: PMC8120243 DOI: 10.3389/fpls.2021.631489] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 03/22/2021] [Indexed: 06/12/2023]
Abstract
Mitochondrial markers can be used to differentiate diverse mitotypes as well as cytoplasms in angiosperms. In cauliflower, cultivation of hybrids is pivotal in remunerative agriculture and cytoplasmic male sterile lines constitute an important component of the hybrid breeding. In diversifying the source of male sterility, it is essential to appropriately differentiate among the available male sterile cytoplasms in cauliflower. PCR polymorphism at the key mitochondrial genes associated with male sterility will be instrumental in analyzing, molecular characterization, and development of mitotype-specific markers for differentiation of different cytoplasmic sources. Presence of auto- and alloplasmic cytonuclear combinations result in complex floral abnormalities. In this context, the present investigation highlighted the utility of organelle genome-based markers in distinguishing cytoplasm types in Indian cauliflowers and unveils the epistatic effects of the cytonuclear interactions influencing floral phenotypes. In PCR-based analysis using a set of primers targeted to orf-138, 76 Indian cauliflower lines depicted the presence of Ogura cytoplasm albeit the amplicons generated exhibited polymorphism within the ofr-138 sequence. The polymorphic fragments were found to be spanning over 200-280 bp and 410-470 bp genomic regions of BnTR4 and orf125, respectively. Sequence analysis revealed that such cytoplasmic genetic variations could be attributed to single nucleotide polymorphisms and insertion or deletions of 31/51 nucleotides. The cytoplasmic effects on varying nuclear-genetic backgrounds rendered an array of floral abnormalities like reduction in flower size, fused flowers, splitted style with the exposed ovule, absence of nonfunctional stamens, and petaloid stamens. These floral malformations caused dysplasia of flower structure affecting female fertility with inefficient nectar production. The finding provides an important reference to ameliorate understanding of mechanism of cytonuclear interactions in floral organ development in Brassicas. The study paves the way for unraveling developmental biology of CMS phenotypes in eukaryotic organisms and intergenomic conflict in plant speciation.
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Affiliation(s)
- Saurabh Singh
- Division of Vegetable Science, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Reeta Bhatia
- Division of Floriculture and Landscaping, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Raj Kumar
- Division of Vegetable Science, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Tusar K. Behera
- Division of Vegetable Science, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Khushboo Kumari
- Division of Vegetable Science, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Achintya Pramanik
- ICAR-Indian Agricultural Research Institute, Regional Station, Kullu Valley, India
| | - Hemant Ghemeray
- Division of Vegetable Science, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Kanika Sharma
- ICAR-Indian Agricultural Research Institute, Regional Station, Kullu Valley, India
| | | | - Shyam S. Dey
- Division of Vegetable Science, ICAR-Indian Agricultural Research Institute, New Delhi, India
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26
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Qi X, Wang K, Yang L, Deng Z, Sun Z. The complete mitogenome sequence of the coral lily ( Lilium pumilum) and the Lanzhou lily ( Lilium davidii) in China. Open Life Sci 2021; 15:1060-1067. [PMID: 33817292 PMCID: PMC7874665 DOI: 10.1515/biol-2020-0102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 07/18/2020] [Accepted: 09/14/2020] [Indexed: 11/24/2022] Open
Abstract
Background The mitogenomes of higher plants are conserved. This study was performed to complete the mitogenome of two China Lilium species (Lilium pumilum Redouté and Lilium davidii var. unicolor (Hoog) cotton). Methods Genomic DNA was separately extracted from the leaves of L. pumilum and L. davidii in triplicate and used for sequencing. The mitogenome of Allium cepa was used as a reference. Genome assembly, annotation and phylogenetic tree were analyzed. Results The mitogenome of L. pumilum and L. davidii was 988,986 bp and 924,401 bp in length, respectively. There were 22 core protein-coding genes (including atp1, atp4, atp6, atp9, ccmB, ccmC, ccmFc, ccmFN1, ccmFN2, cob, cox3, matR, mttB, nad1, nad2, nad3, nad4, nad4L, nad5, nad6, nad7 and nad9), one open reading frame and one ribosomal protein-coding gene (rps12) in the mitogenomes. Compared with the A. cepa mitogenome, the coding sequence of the 24 genes and intergenic spacers in L. pumilum and L. davidii mitogenome contained 1,621 and 1,617 variable sites, respectively. In the phylogenetic tree, L. pumilum and L. davidii were distinct from A. cepa (NC_030100). Conclusions L. pumilum and L. davidii mitogenomes have far distances from other plants. This study provided additional information on the species resources of China Lilium.
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Affiliation(s)
- Xiangying Qi
- China Lily Laboratory, Shaanxi Engineering and Technological Research Center for Conversation and Utilization of Regional Biological Resources, Yan'an University, Yan'an, 716000, Shaanxi, China
| | - Kaiqi Wang
- China Lily Laboratory, Shaanxi Engineering and Technological Research Center for Conversation and Utilization of Regional Biological Resources, Yan'an University, Yan'an, 716000, Shaanxi, China
| | - Liping Yang
- School of Advanced Agriculture and Bioengineering, Yangtze Normal University, Chongqing, 408100, China
| | - Zhenshan Deng
- China Lily Laboratory, Shaanxi Engineering and Technological Research Center for Conversation and Utilization of Regional Biological Resources, Yan'an University, Yan'an, 716000, Shaanxi, China
| | - Zhihong Sun
- China Lily Laboratory, Shaanxi Engineering and Technological Research Center for Conversation and Utilization of Regional Biological Resources, Yan'an University, Yan'an, 716000, Shaanxi, China
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27
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Plazzi F, Puccio G, Passamonti M. HERMES: An improved method to test mitochondrial genome molecular synapomorphies among clades. Mitochondrion 2021; 58:285-295. [PMID: 33639269 DOI: 10.1016/j.mito.2021.02.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 01/10/2021] [Accepted: 02/12/2021] [Indexed: 02/06/2023]
Abstract
Mitochondrial chromosomes have diversified among eukaryotes and many different architectures and features are now acknowledged for this genome. Here we present the improved HERMES index, which can measure and quantify the amount of molecular change experienced by mitochondrial genomes. We test the improved approach with ten molecular phylogenetic studies based on complete mitochondrial genomes, representing six bilaterian Phyla. In most cases, HERMES analysis spotted out clades or single species with peculiar molecular synapomorphies, allowing to identify phylogenetic and ecological patterns. The software presented herein handles linear, circular, and multi-chromosome genomes, thus widening the HERMES scope to the complete eukaryotic domain.
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Affiliation(s)
- Federico Plazzi
- Department of Biological, Geological and Environmental Sciences, University of Bologna, via Selmi, 3, 40126 Bologna, Italy.
| | - Guglielmo Puccio
- Department of Biological, Geological and Environmental Sciences, University of Bologna, via Selmi, 3, 40126 Bologna, Italy.
| | - Marco Passamonti
- Department of Biological, Geological and Environmental Sciences, University of Bologna, via Selmi, 3, 40126 Bologna, Italy.
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28
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Park S, Park S. Large-scale phylogenomics reveals ancient introgression in Asian Hepatica and new insights into the origin of the insular endemic Hepatica maxima. Sci Rep 2020; 10:16288. [PMID: 33004955 PMCID: PMC7529770 DOI: 10.1038/s41598-020-73397-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 09/14/2020] [Indexed: 11/09/2022] Open
Abstract
Hepatica maxima is native to Ulleungdo, which is one of the oceanic islands in Korea, and it likely originated via anagenetic speciation from the Korean mainland species H. asiatica. However, the relationships among the Asian lineages remain unresolved. Phylogenomics based on plant genomes can provide new insights into the evolutionary history of plants. We first generated plastid, mitochondrial and transcriptome sequences of the insular endemic species H. maxima. Using the genomic data for H. maxima, we obtained a phylogenomic dataset consisting of 76 plastid, 37 mitochondrial and 413 nuclear genes from Asian Hepatica and two outgroups. Coalescent- and concatenation-based methods revealed cytonuclear and organellar discordance in the lineage. The presence of gynodioecy with cytoplasmic male sterility in Asian Hepatica suggests that the discordance is correlated with potential disruption of linkage disequilibrium between the organellar genomes. Species network analyses revealed a deep history of hybridization and introgression in Asian Hepatica. We discovered that ancient and recent introgression events occurred throughout the evolutionary history of the insular endemic species H. maxima. The introgression may serve as an important source of genetic variation to facilitate adaptation to the Ulleungdo environment.
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Affiliation(s)
- Seongjun Park
- Institute of Natural Science, Yeungnam University, Gyeongsan, Gyeongbuk, 38541, South Korea.,Department of Life Sciences, Yeungnam University, Gyeongsan, Gyeongbuk, 38541, South Korea
| | - SeonJoo Park
- Department of Life Sciences, Yeungnam University, Gyeongsan, Gyeongbuk, 38541, South Korea.
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29
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Gonçalves DJP, Jansen RK, Ruhlman TA, Mandel JR. Under the rug: Abandoning persistent misconceptions that obfuscate organelle evolution. Mol Phylogenet Evol 2020; 151:106903. [PMID: 32628998 DOI: 10.1016/j.ympev.2020.106903] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 06/29/2020] [Indexed: 02/01/2023]
Abstract
The advent and advance of next generation sequencing over the past two decades made it possible to accumulate large quantities of sequence reads that could be used to assemble complete or nearly complete organelle genomes (plastome or mitogenome). The result has been an explosive increase in the availability of organelle genome sequences with over 4000 different species of green plants currently available on GenBank. During the same time period, plant molecular biologists greatly enhanced the understanding of the structure, repair, replication, recombination, transcription and translation, and inheritance of organelle DNA. Unfortunately many plant evolutionary biologists are unaware of or have overlooked this knowledge, resulting in misrepresentation of several phenomena that are critical for phylogenetic and evolutionary studies using organelle genomes. We believe that confronting these misconceptions about organelle genome organization, composition, and inheritance will improve our understanding of the evolutionary processes that underly organelle evolution. Here we discuss four misconceptions that can limit evolutionary biology studies and lead to inaccurate phylogenies and incorrect structure of the organellar DNA used to infer organelle evolution.
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Affiliation(s)
- Deise J P Gonçalves
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA; Department of Integrative Biology, The University of Texas at Austin, Austin, TX 78713, USA.
| | - Robert K Jansen
- Department of Integrative Biology, The University of Texas at Austin, Austin, TX 78713, USA; Center of Excellence for Bionanoscience Research, Department of Biological Sciences, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Tracey A Ruhlman
- Department of Integrative Biology, The University of Texas at Austin, Austin, TX 78713, USA
| | - Jennifer R Mandel
- Department of Biological Sciences, Center for Biodiversity Research, University of Memphis, Memphis, TN 38152, USA
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30
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Abstract
Ever since its discovery, the double-stranded DNA contained in the mitochondria of eukaryotes has fascinated researchers because of its bacterial endosymbiotic origin, crucial role in encoding subunits of the respiratory complexes, compact nature, and specific inheritance mechanisms. In the last few years, high-throughput sequencing techniques have accelerated the sequencing of mitochondrial genomes (mitogenomes) and uncovered the great diversity of organizations, gene contents, and modes of replication and transcription found in living eukaryotes. Some early divergent lineages of unicellular eukaryotes retain certain synteny and gene content resembling those observed in the genomes of alphaproteobacteria (the inferred closest living group of mitochondria), whereas others adapted to anaerobic environments have drastically reduced or even lost the mitogenome. In the three main multicellular lineages of eukaryotes, mitogenomes have pursued diverse evolutionary trajectories in which different types of molecules (circular versus linear and single versus multipartite), gene structures (with or without self-splicing introns), gene contents, gene orders, genetic codes, and transfer RNA editing mechanisms have been selected. Whereas animals have evolved a rather compact mitochondrial genome between 11 and 50 Kb in length with a highly conserved gene content in bilaterians, plants exhibit large mitochondrial genomes of 66 Kb to 11.3 Mb with large intergenic repetitions prone to recombination, and fungal mitogenomes have intermediate sizes of 12 to 236 Kb.
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Affiliation(s)
- Rafael Zardoya
- Departamento de Biodiversidad y Biología Evolutiva, Museo Nacional de Ciencias Naturales (MNCN-CSIC), Madrid, Spain
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31
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Yang W, Zou J, Wang J, Li N, Luo X, Jiang X, Li S. Wide crossing diversify mitogenomes of rice. BMC PLANT BIOLOGY 2020; 20:159. [PMID: 32293284 PMCID: PMC7160995 DOI: 10.1186/s12870-020-02380-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 04/01/2020] [Indexed: 05/11/2023]
Abstract
BACKGROUND In most angiosperms, the inheritance of the mitochondria takes place in a typical maternal manner. However, very less information is available about if the existence of structural variations or not in mitochondrial genomes (mitogenomes) between maternal parents and their progenies. RESULTS In order to find the answer, a stable rice backcross inbred line (BIL) population was derived from the crosses of Oryza glaberrima/Oryza sativa//Oryza sativa. The current study presents a comparative analysis of the mitogenomes between maternal parents and five BILs. There were recorded universal structural variations such as reversal, translocation, fusion, and fission among the BILs. The repeat-mediated recombination and non-homologous end-joining contributed virtually equal to the rearrangement of mitogenomes. Similarly, the relative order, copy-number, expression level, and RNA-editing rate of mitochondrial genes were also extensively varied among BILs. CONCLUSIONS These novel findings unraveled an unusual mystery of the maternal inheritance and possible cause for heterogeneity of mitogenomes in rice population. The current piece of work will greatly develop our understanding of the plant nucleo-cytoplasmic interaction and their potential role in plant growth and developmental processes.
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Affiliation(s)
- Weilong Yang
- State Key Laboratory of Hybrid Rice, Key Laboratory for Research and Utilization of Heterosis in Indica Rice of Ministry of Agriculture, Engineering Research Center for Plant Biotechnology and Germplasm Utilization of Ministry of Education, College of Life Science, Wuhan University, Wuhan, 430072, China
| | - Jianing Zou
- State Key Laboratory of Hybrid Rice, Key Laboratory for Research and Utilization of Heterosis in Indica Rice of Ministry of Agriculture, Engineering Research Center for Plant Biotechnology and Germplasm Utilization of Ministry of Education, College of Life Science, Wuhan University, Wuhan, 430072, China
| | - Jiajia Wang
- State Key Laboratory of Hybrid Rice, Key Laboratory for Research and Utilization of Heterosis in Indica Rice of Ministry of Agriculture, Engineering Research Center for Plant Biotechnology and Germplasm Utilization of Ministry of Education, College of Life Science, Wuhan University, Wuhan, 430072, China
| | - Nengwu Li
- State Key Laboratory of Hybrid Rice, Key Laboratory for Research and Utilization of Heterosis in Indica Rice of Ministry of Agriculture, Engineering Research Center for Plant Biotechnology and Germplasm Utilization of Ministry of Education, College of Life Science, Wuhan University, Wuhan, 430072, China
| | - Xiaoyun Luo
- State Key Laboratory of Hybrid Rice, Key Laboratory for Research and Utilization of Heterosis in Indica Rice of Ministry of Agriculture, Engineering Research Center for Plant Biotechnology and Germplasm Utilization of Ministry of Education, College of Life Science, Wuhan University, Wuhan, 430072, China
| | - Xiaofen Jiang
- State Key Laboratory of Hybrid Rice, Key Laboratory for Research and Utilization of Heterosis in Indica Rice of Ministry of Agriculture, Engineering Research Center for Plant Biotechnology and Germplasm Utilization of Ministry of Education, College of Life Science, Wuhan University, Wuhan, 430072, China
| | - Shaoqing Li
- State Key Laboratory of Hybrid Rice, Key Laboratory for Research and Utilization of Heterosis in Indica Rice of Ministry of Agriculture, Engineering Research Center for Plant Biotechnology and Germplasm Utilization of Ministry of Education, College of Life Science, Wuhan University, Wuhan, 430072, China.
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32
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Hill GE. Mitonuclear Compensatory Coevolution. Trends Genet 2020; 36:403-414. [PMID: 32396834 DOI: 10.1016/j.tig.2020.03.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 02/27/2020] [Accepted: 03/08/2020] [Indexed: 01/03/2023]
Abstract
In bilaterian animals, the mitochondrial genome is small, haploid, does not typically recombine, and is subject to accumulation of deleterious alleles via Muller's ratchet. These basic features of the genomic architecture present a paradox: mutational erosion of these genomes should lead to decline in mitochondrial function over time, yet no such decline is observed. Compensatory coevolution, whereby the nuclear genome evolves to compensate for the deleterious alleles in the mitochondrial genome, presents a potential solution to the paradox of Muller's ratchet without loss of function. Here, I review different proposed forms of mitonuclear compensatory coevolution. Empirical evidence from diverse eukaryotic taxa supports the mitonuclear compensatory coevolution hypothesis, but the ubiquity and importance of such compensatory coevolution remains a topic of debate.
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Affiliation(s)
- Geoffrey E Hill
- Department of Biological Science, 331 Funchess Hall, Auburn University, Auburn, AL 36849-5414, USA.
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33
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Postel Z, Touzet P. Cytonuclear Genetic Incompatibilities in Plant Speciation. PLANTS 2020; 9:plants9040487. [PMID: 32290056 PMCID: PMC7238192 DOI: 10.3390/plants9040487] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 04/03/2020] [Accepted: 04/07/2020] [Indexed: 12/13/2022]
Abstract
Due to the endosymbiotic origin of organelles, a pattern of coevolution and coadaptation between organellar and nuclear genomes is required for proper cell function. In this review, we focus on the impact of cytonuclear interaction on the reproductive isolation of plant species. We give examples of cases where species exhibit barriers to reproduction which involve plastid-nuclear or mito-nuclear genetic incompatibilities, and describe the evolutionary processes at play. We also discuss potential mechanisms of hybrid fitness recovery such as paternal leakage. Finally, we point out the possible interplay between plant mating systems and cytonuclear coevolution, and its consequence on plant speciation.
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34
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Evolving mtDNA populations within cells. Biochem Soc Trans 2020; 47:1367-1382. [PMID: 31484687 PMCID: PMC6824680 DOI: 10.1042/bst20190238] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 08/06/2019] [Accepted: 08/08/2019] [Indexed: 12/14/2022]
Abstract
Mitochondrial DNA (mtDNA) encodes vital respiratory machinery. Populations of mtDNA molecules exist in most eukaryotic cells, subject to replication, degradation, mutation, and other population processes. These processes affect the genetic makeup of cellular mtDNA populations, changing cell-to-cell distributions, means, and variances of mutant mtDNA load over time. As mtDNA mutant load has nonlinear effects on cell functionality, and cell functionality has nonlinear effects on tissue performance, these statistics of cellular mtDNA populations play vital roles in health, disease, and inheritance. This mini review will describe some of the better-known ways in which these populations change over time in different organisms, highlighting the importance of quantitatively understanding both mutant load mean and variance. Due to length constraints, we cannot attempt to be comprehensive but hope to provide useful links to some of the many excellent studies on these topics.
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Schaack S, Ho EKH, Macrae F. Disentangling the intertwined roles of mutation, selection and drift in the mitochondrial genome. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190173. [PMID: 31787045 PMCID: PMC6939366 DOI: 10.1098/rstb.2019.0173] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/16/2019] [Indexed: 12/31/2022] Open
Abstract
Understanding and quantifying the rates of change in the mitochondrial genome is a major component of many areas of biological inquiry, from phylogenetics to human health. A critical parameter in understanding rates of change is estimating the mitochondrial mutation rate (mtDNA MR). Although the first direct estimates of mtDNA MRs were reported almost 20 years ago, the number of estimates has not grown markedly since that time. This is largely owing to the challenges associated with time- and labour-intensive mutation accumulation (MA) experiments. But even MA experiments do not solve a major problem with estimating mtDNA MRs-the challenge of disentangling the role of mutation from other evolutionary forces acting within the cell. Now that it is widely understood that any newly generated mutant allele in the mitochondria will initially be at very low frequency (1/N, where N is the number of mtDNA molecules in the cell), the importance of understanding the effective population size (Ne) of the mtDNA and the size of genetic bottlenecks during gametogenesis and development has come into the spotlight. In addition to these factors regulating the role of genetic drift, advances in our understanding of mitochondrial replication and turnover allow us to more easily envision how natural selection within the cell might favour or purge mutations in multi-copy organellar genomes. Here, we review the unique features of the mitochondrial genome that pose a challenge for accurate MR estimation and discuss ways to overcome those challenges. Estimates of mtDNA MRs remain one of the most widely used parameters in biology, thus accurate quantification and a deeper understanding of how and why they may vary within and between individuals, populations and species is an important goal. This article is part of the theme issue 'Linking the mitochondrial genotype to phenotype: a complex endeavour'.
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Affiliation(s)
- Sarah Schaack
- Department of Biology, Reed College, Portland, OR 97202, USA
| | - Eddie K H Ho
- Department of Biology, Reed College, Portland, OR 97202, USA
| | - Fenner Macrae
- Department of Biology, Reed College, Portland, OR 97202, USA
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Adhikari B, Caruso CM, Case AL. Beyond balancing selection: frequent mitochondrial recombination contributes to high-female frequencies in gynodioecious Lobelia siphilitica (Campanulaceae). THE NEW PHYTOLOGIST 2019; 224:1381-1393. [PMID: 31442304 DOI: 10.1111/nph.16136] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Accepted: 08/13/2019] [Indexed: 06/10/2023]
Abstract
Gynodioecy is a sexual system in which females and hermaphrodites co-occur. In most gynodioecious angiosperms, sex is determined by an interaction between mitochondrial male-sterility genes (CMS) that arise via recombination and nuclear restorer alleles that evolve to suppress them. In theory, gynodioecy occurs when multiple CMS types are maintained at equilibrium frequencies by balancing selection. However, some gynodioecious populations contain very high frequencies of females. High female frequencies are not expected under balancing selection, but could be explained by the repeated introduction of novel CMS types. To test for balancing selection and/or the repeated introduction of novel CMS, we characterised cytoplasmic haplotypes from 61 populations of Lobelia siphilitica that vary widely in female frequency. We confirmed that mitotype diversity and female frequency were positively correlated across populations, consistent with balancing selection. However, while low-female populations hosted mostly common mitotypes, high-female populations and female plants hosted mostly rare, recombinant mitotypes likely to carry novel CMS types. Our results suggest that balancing selection maintains established CMS types across this species, but extreme female frequencies result from frequent invasion by novel CMS types. We conclude that balancing selection alone cannot account for extreme population sex-ratio variation within a gynodioecious species.
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Affiliation(s)
- Binaya Adhikari
- Department of Biological Sciences, Kent State University, Kent, OH, 44240, USA
- Department of Biological and Environmental Sciences, Longwood University, Farmville, VA, 23909, USA
| | - Christina M Caruso
- Department of Integrative Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Andrea L Case
- Department of Biological Sciences, Kent State University, Kent, OH, 44240, USA
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Ramsey AJ, McCauley DE, Mandel JR. Heteroplasmy and Patterns of Cytonuclear Linkage Disequilibrium in Wild Carrot. Integr Comp Biol 2019; 59:1005-1015. [DOI: 10.1093/icb/icz102] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Abstract
Organellar genomes are considered to be strictly uniparentally-inherited. Uniparental inheritance allows for cytonuclear coevolution and the development of highly coordinated cytonuclear interactions. Yet, instances of biparental inheritance have been documented across eukaryotes. Biparental inheritance in otherwise uniparentally-inherited organelles is termed leakage (maternal or paternal) and allows for the presence of multiple variants of the same organellar genome within an individual, called heteroplasmy. It is unclear what, if any, evolutionary consequences are placed on nuclear and/or organellar genomes due to heteroplasmy. One way of accessing cytonuclear interactions and potential coevolution is through calculating cytonuclear linkage disequilibrium (cnLD), or the non-random association of alleles between nuclear and organellar genomes. Patterns of cnLD can indicate positive or negative cytonuclear selection, coevolution between the nuclear and organellar genomes, non-traditional organellar inheritance, or instances of ancestral heteroplasmy. In plants, cytonuclear interactions have been shown to play a role in cytoplasmic male sterility which occurs in gynodioecious species and is associated with leakage. We used the gynodioecious species, Daucus carota L. spp. carota, or wild carrot, to investigate cnLD. We genotyped a total of 265 individuals from two regions of the USA at 15 nuclear microsatellites, the mitochondrial genes cox1 and atp9, and an intergenic region between trnS and trnG (StoG) in the plastid genome to calculate nuclear–nuclear LD (nucLD), cnLD, and organellar LD (i.e., within the mtDNA and between mtDNA and ptDNA) within the two regions. We were further able to identify cox1 and StoG heteroplasmy and calculate some of the same LD measures within heteroplasmic and homoplasmic (non-heteroplasmic) datasets. We used a Z-transformation test to demonstrate that heteroplasmic individuals display significantly higher levels of cnLD within both regions. In spite of this, within and between organellar LD is low to moderate. Given these patterns of LD in two regions of the USA in which gene flow has been shown to occur between crop and wild carrot, we suggest that heteroplasmy is an evolutionary mechanism which permits the maintenance of cnLD while also acting to disrupt organellar LD.
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Affiliation(s)
- Adam J Ramsey
- Department of Biological Sciences, The University of Memphis, 3700 Walker Avenue, Memphis, TN 38152, USA
| | - David E McCauley
- Department of Biological Sciences, Vanderbilt University, VU Station B, Nashville, TN Box 351634, USA
| | - Jennifer R Mandel
- Department of Biological Sciences, Vanderbilt University, VU Station B, Nashville, TN Box 351634, USA
- W. Harry Feinstone Center for Genomic Research, The University of Memphis, 3774 Walker Avenue, Memphis, TN 38152, USA
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Abstract
Mitochondria, a nearly ubiquitous feature of eukaryotes, are derived from an ancient symbiosis. Despite billions of years of cooperative coevolution - in what is arguably the most important mutualism in the history of life - the persistence of mitochondrial genomes also creates conditions for genetic conflict with the nucleus. Because mitochondrial genomes are present in numerous copies per cell, they are subject to both within- and among-organism levels of selection. Accordingly, 'selfish' genotypes that increase their own proliferation can rise to high frequencies even if they decrease organismal fitness. It has been argued that uniparental (often maternal) inheritance of cytoplasmic genomes evolved to curtail such selfish replication by minimizing within-individual variation and, hence, within-individual selection. However, uniparental inheritance creates conditions for cytonuclear conflict over sex determination and sex ratio, as well as conditions for sexual antagonism when mitochondrial variants increase transmission by enhancing maternal fitness but have the side-effect of being harmful to males (i.e., 'mother's curse'). Here, we review recent advances in understanding selfish replication and sexual antagonism in the evolution of mitochondrial genomes and the mechanisms that suppress selfish interactions, drawing parallels and contrasts with other organelles (plastids) and bacterial endosymbionts that arose more recently. Although cytonuclear conflict is widespread across eukaryotes, it can be cryptic due to nuclear suppression, highly variable, and lineage-specific, reflecting the diverse biology of eukaryotes and the varying architectures of their cytoplasmic genomes.
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Affiliation(s)
- Justin C Havird
- Department of Integrative Biology, The University of Texas, Austin, TX 78712, USA.
| | - Evan S Forsythe
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Alissa M Williams
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - John H Werren
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
| | - Damian K Dowling
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
| | - Daniel B Sloan
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA
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Bergero R, Levsen N, Wolff K, Charlesworth D. Arms races with mitochondrial genome soft sweeps in a gynodioecious plant, Plantago lanceolata. Mol Ecol 2019; 28:2772-2785. [PMID: 31100183 DOI: 10.1111/mec.15121] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 04/22/2019] [Accepted: 04/23/2019] [Indexed: 11/26/2022]
Abstract
Biological situations involving conflict can create arms race situations with repeated fixations of different functional variants, producing selective sweeps and lowering neutral diversity in genome regions linked to the functional locus. However, they can sometimes lead to balancing selection, potentially creating long coalescent times for sites with functionally different variants, and, if recombination occurs rarely, for extended haplotypes carrying such variants. We tested between these possibilities in a gynodioecious plant, Plantago lanceolata, in which cytoplasmic male-sterility factors conflict with nuclear restorers of male fertility. We find low mitochondrial diversity, which does not support very long-term coexistence of highly diverged mitochondrial haplotypes. Interestingly, however, we found a derived haplotype that is associated with male fertility in a restricted geographic region, and that has fixed differences from the ancestral sequence in several genes, suggesting that it did not arise very recently. Taken together, the results suggest arms race events that involved "soft" selective sweeps involving a moderately old-established haplotype, consistent with the frequency fluctuations predicted by theoretical models of gynodioecy.
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Affiliation(s)
- Roberta Bergero
- Ashworth Laboratory, School of Biological Sciences, Institute of Evolutionary Biology, The University of Edinburgh, Edinburgh, UK
| | - Nick Levsen
- School of Natural and Environmental Sciences, Newcastle University, Newcastle Upon Tyne, Tyne and Wear, UK
| | - Kirsten Wolff
- School of Natural and Environmental Sciences, Newcastle University, Newcastle Upon Tyne, Tyne and Wear, UK
| | - Deborah Charlesworth
- Ashworth Laboratory, School of Biological Sciences, Institute of Evolutionary Biology, The University of Edinburgh, Edinburgh, UK
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Wu Z, Sloan DB. Recombination and intraspecific polymorphism for the presence and absence of entire chromosomes in mitochondrial genomes. Heredity (Edinb) 2019; 122:647-659. [PMID: 30356223 PMCID: PMC6461862 DOI: 10.1038/s41437-018-0153-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 09/08/2018] [Accepted: 09/25/2018] [Indexed: 11/09/2022] Open
Abstract
Although mitochondrial genomes are typically thought of as single circular molecules, these genomes are fragmented into multiple chromosomes in many eukaryotes, raising intriguing questions about inheritance and (in)stability of mtDNA in such systems. A previous comparison of mitochondrial genomes from two different individuals of the angiosperm species Silene noctiflora found variation in the presence of entire mitochondrial chromosomes. Here, we expand on this work with a geographically diverse sampling of 25 S. noctiflora populations and the closely related species S. turkestanica and S. undulata. Using a combination of deep sequencing and PCR-based screening for the presence of 22 different mitochondrial chromosomes, we found extensive variation in the complement of chromosomes across individuals. Much of this variation could be attributed to recent chromosome loss events, suggesting that the massively expanded and fragmented mitochondrial genomes of S. noctiflora may have entered a phase of genome reduction in which they are losing entire chromosomes at a rapid rate. Sequence analysis of mitochondrial and plastid genomes revealed genealogical differences both between these organelles and within the mitochondrial genome, indicating a history of recombination. Evidence that recombination has generated novel combinations of alleles was more frequent between loci on different mitochondrial chromosomes than it was within chromosomes. Therefore, the fragmentation of mitochondrial genomes and the assortment of chromosomes during mitochondrial inheritance appears to have contributed to a history of sexual-like recombination in the mtDNA of this species.
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Affiliation(s)
- Zhiqiang Wu
- Department of Biology, Colorado State University, Fort Collins, CO, 80523, USA.
| | - Daniel B Sloan
- Department of Biology, Colorado State University, Fort Collins, CO, 80523, USA
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Shen J, Shou W, Zhang Y, Yuan G, Zhao Y, Chen J, Havey MJ. Rare maternal and biparental transmission of the cucumber mitochondrial DNA reveals sorting of polymorphisms among progenies. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2019; 132:1223-1233. [PMID: 30758532 DOI: 10.1007/s00122-018-03274-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Accepted: 12/22/2018] [Indexed: 05/28/2023]
Abstract
We used a mitochondrial (mt) mutant of cucumber to document rare maternal transmission of mt polymorphisms and demonstrate that polymorphisms can become more prevalent and sort to progenies to increase mt DNA diversity. The mitochondrial (mt) DNAs of most angiosperms show maternal inheritance, although relatively rare biparental or paternal transmission has been documented. The mt DNAs of plants in the genus Cucumis (family Cucurbitaceae) are paternally transmitted in intra- and interspecific crosses. MSC16 is an inbred line of cucumber (Cucumis sativus) with a mitochondrially associated mosaic (MSC) phenotype. MSC16 was crossed as the male parent to wild-type cultivar Calypso, and hybrid progenies were evaluated for the wild-type phenotype in order to screen for rare maternal or biparental transmission of the mt DNA. We then used standard and droplet digital (dd) PCR to study the transmission of polymorphic mt markers across three generations. We observed evidence for occasional maternal and biparental transmission of the mt DNA in cucumber. The transmission of specific regions of the maternal mt DNA could be as high as 17.8%, although the amounts of these maternal regions were often much lower relative to paternally transmitted regions. Different combinations of maternal and paternal mt polymorphisms were detected in progenies across generations, indicating that relatively rare maternal regions can be transmitted to progenies and become predominant to increase mt DNA diversity over generations.
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Affiliation(s)
- Jia Shen
- Institute of Vegetables, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
- College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China
| | - Weisong Shou
- Institute of Vegetables, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
| | - Yuejian Zhang
- Institute of Vegetables, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
| | - Gaoya Yuan
- College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yu Zhao
- College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China
| | - Jinfeng Chen
- College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China
| | - Michael J Havey
- USDA-ARS and Department of Horticulture, University of Wisconsin, Madison, WI, 53706, USA.
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Radzvilavicius AL, Lane N, Pomiankowski A. Sexual conflict explains the extraordinary diversity of mechanisms regulating mitochondrial inheritance. BMC Biol 2017; 15:94. [PMID: 29073898 PMCID: PMC5658935 DOI: 10.1186/s12915-017-0437-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 10/10/2017] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Mitochondria are predominantly inherited from the maternal gamete, even in unicellular organisms. Yet an extraordinary array of mechanisms enforce uniparental inheritance, which implies shifting selection pressures and multiple origins. RESULTS We consider how this high turnover in mechanisms controlling uniparental inheritance arises using a novel evolutionary model in which control of mitochondrial transmission occurs either during spermatogenesis (by paternal nuclear genes) or at/after fertilization (by maternal nuclear genes). The model treats paternal leakage as an evolvable trait. Our evolutionary analysis shows that maternal control consistently favours strict uniparental inheritance with complete exclusion of sperm mitochondria, whereas some degree of paternal leakage of mitochondria is an expected outcome under paternal control. This difference arises because mito-nuclear linkage builds up with maternal control, allowing the greater variance created by asymmetric inheritance to boost the efficiency of purifying selection and bring benefits in the long term. In contrast, under paternal control, mito-nuclear linkage tends to be much weaker, giving greater advantage to the mixing of cytotypes, which improves mean fitness in the short term, even though it imposes a fitness cost to both mating types in the long term. CONCLUSIONS Sexual conflict is an inevitable outcome when there is competition between maternal and paternal control of mitochondrial inheritance. If evolution has led to complete uniparental inheritance through maternal control, it creates selective pressure on the paternal nucleus in favour of subversion through paternal leakage, and vice versa. This selective divergence provides a reason for the repeated evolution of novel mechanisms that regulate the transmission of paternal mitochondria, both in the fertilized egg and spermatogenesis. Our analysis suggests that the widespread occurrence of paternal leakage and prevalence of heteroplasmy are natural outcomes of this sexual conflict.
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Affiliation(s)
- Arunas L Radzvilavicius
- Centre for Mathematics and Physics in the Life Sciences and Experimental Biology, University College London, Gower Street, London, WC1E 6BT, UK
- Department of Genetics, Evolution and Environment, University College London, Gower Street, London, WC1E 6BT, UK
- Department of Biology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Nick Lane
- Centre for Mathematics and Physics in the Life Sciences and Experimental Biology, University College London, Gower Street, London, WC1E 6BT, UK
- Department of Genetics, Evolution and Environment, University College London, Gower Street, London, WC1E 6BT, UK
| | - Andrew Pomiankowski
- Centre for Mathematics and Physics in the Life Sciences and Experimental Biology, University College London, Gower Street, London, WC1E 6BT, UK.
- Department of Genetics, Evolution and Environment, University College London, Gower Street, London, WC1E 6BT, UK.
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Mandel JR, Ramsey AJ, Iorizzo M, Simon PW. Patterns of Gene Flow between Crop and Wild Carrot, Daucus carota (Apiaceae) in the United States. PLoS One 2016; 11:e0161971. [PMID: 27603516 PMCID: PMC5014312 DOI: 10.1371/journal.pone.0161971] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 08/15/2016] [Indexed: 11/18/2022] Open
Abstract
Studies of gene flow between crops and their wild relatives have implications for both management practices for cultivation and understanding the risk of transgene escape. These types of studies may also yield insight into population dynamics and the evolutionary consequences of gene flow for wild relatives of crop species. Moreover, the comparison of genetic markers with different modes of inheritance, or transmission, such as those of the nuclear and chloroplast genomes, can inform the relative risk of transgene escape via pollen versus seed. Here we investigate patterns of gene flow between crop and wild carrot, Daucus carota (Apiaceae) in two regions of the United States. We employed 15 nuclear simple sequence repeat (SSR) markers and one polymorphic chloroplast marker. Further, we utilized both conventional population genetic metrics along with Shannon diversity indices as the latter have been proposed to be more sensitive to allele frequency changes and differentiation. We found that populations in both regions that were proximal to crop fields showed lower levels of differentiation to the crops than populations that were located farther away. We also found that Shannon measures were more sensitive to differences in both genetic diversity and differentiation in our study. Finally, we found indirect evidence of paternal transmission of chloroplast DNA and accompanying lower than expected levels of chloroplast genetic structure amongst populations as might be expected if chloroplast DNA genes flow through both seed and pollen. Our findings of substantial gene flow for both nuclear and chloroplast markers demonstrate the efficiency of both pollen and seed to transfer genetic information amongst populations of carrot.
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Affiliation(s)
- Jennifer R. Mandel
- Department of Biological Sciences, The University of Memphis, Memphis, Tennessee, United States of America
- W. Harry Feinstone Center for Genomic Research, The University of Memphis, Memphis, Tennessee, United States of America
- * E-mail:
| | - Adam J. Ramsey
- Department of Biological Sciences, The University of Memphis, Memphis, Tennessee, United States of America
| | - Massimo Iorizzo
- Plants for Human Health Institute, Department of Horticultural Science, North Carolina State University, Kannapolis, North Carolina, United States of America
| | - Philipp W. Simon
- USDA-Agricultural Research Service, Vegetable Crops Unit, University of Wisconsin-Madison, Wisconsin, United States of America
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45
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Cole LW. The Evolution of Per-cell Organelle Number. Front Cell Dev Biol 2016; 4:85. [PMID: 27588285 PMCID: PMC4988970 DOI: 10.3389/fcell.2016.00085] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 08/04/2016] [Indexed: 11/13/2022] Open
Abstract
Organelles with their own distinct genomes, such as plastids and mitochondria, are found in most eukaryotic cells. As these organelles and their host cells have evolved, the partitioning of metabolic processes and the encoding of interacting gene products have created an obligate codependence. This relationship has played a role in shaping the number of organelles in cells through evolution. Factors such as stochastic evolutionary forces acting on genes involved in organelle biogenesis, organelle-nuclear gene interactions, and physical limitations may, to varying degrees, dictate the selective constraint that per-cell organelle number is under. In particular, coordination between nuclear and organellar gene expression may be important in maintaining gene product stoichiometry, which may have a significant role in constraining the evolution of this trait.
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Affiliation(s)
- Logan W Cole
- Department of Biology, Indiana University Bloomington, IN, USA
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46
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Lambertini C. Heteroplasmy due to chloroplast paternal leakage: another insight into Phragmites haplotypic diversity in North America. Biol Invasions 2016. [DOI: 10.1007/s10530-016-1193-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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47
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Frequent, geographically structured heteroplasmy in the mitochondria of a flowering plant, ribwort plantain (Plantago lanceolata). Heredity (Edinb) 2016; 117:1-7. [PMID: 26956565 PMCID: PMC4901351 DOI: 10.1038/hdy.2016.15] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 01/26/2016] [Accepted: 02/02/2016] [Indexed: 12/20/2022] Open
Abstract
Recent research has convincingly documented cases of mitochondrial heteroplasmy in a small set of wild and cultivated plant species. Heteroplasmy is suspected to be common in flowering plants and investigations of additional taxa may help understand the mechanisms generating heteroplasmy as well as its effects on plant phenotypes. The role of mitochondrial heteroplasmy is of particular interest in plants as cytoplasmic male sterility is controlled by mitochondrial genotypes, sometimes leading to co-occurring female and hermaphroditic individuals (gynodioecy). Paternal leakage may be important in the evolution of mating systems in such populations. We conducted a genetic survey of the gynodioecious plant Plantago lanceolata, in which heteroplasmy has not previously been reported, and estimated the frequencies of mitochondrial genotypes and heteroplasmy. Sanger sequence genotyping of 179 individuals from 15 European populations for two polymorphic mitochondrial loci, atp6 and rps12, identified 15 heteroplasmic individuals. These were distributed among 6 of the 10 populations that had polymorphisms in the target loci and represented 8% of all sampled individuals and 15% of the individuals in those 6 populations. The incidence was highest in Northern England and Scotland. Our results are consistent with geographic differences in the incidence of paternal leakage and/or the rates of nuclear restoration of male fertility.
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Abstract
Mitochondrial DNA (mtDNA) is predominantly maternally inherited in eukaryotes. Diverse molecular mechanisms underlying the phenomenon of strict maternal inheritance (SMI) of mtDNA have been described, but the evolutionary forces responsible for its predominance in eukaryotes remain to be elucidated. Exceptions to SMI have been reported in diverse eukaryotic taxa, leading to the prediction that several distinct molecular mechanisms controlling mtDNA transmission are present among the eukaryotes. We propose that these mechanisms will be better understood by studying the deviations from the predominating pattern of SMI. This minireview summarizes studies on eukaryote species with unusual or rare mitochondrial inheritance patterns, i.e., other than the predominant SMI pattern, such as maternal inheritance of stable heteroplasmy, paternal leakage of mtDNA, biparental and strictly paternal inheritance, and doubly uniparental inheritance of mtDNA. The potential genes and mechanisms involved in controlling mitochondrial inheritance in these organisms are discussed. The linkage between mitochondrial inheritance and sex determination is also discussed, given that the atypical systems of mtDNA inheritance examined in this minireview are frequently found in organisms with uncommon sexual systems such as gynodioecy, monoecy, or andromonoecy. The potential of deviations from SMI for facilitating a better understanding of a number of fundamental questions in biology, such as the evolution of mtDNA inheritance, the coevolution of nuclear and mitochondrial genomes, and, perhaps, the role of mitochondria in sex determination, is considerable.
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Affiliation(s)
- Sophie Breton
- a Department of Biological Sciences, Université de Montréal, Montréal, QC H3C 3J7, Canada
| | - Donald T Stewart
- b Department of Biology, Acadia University, Wolfville, NS B4P 2R6, Canada
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49
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Pervasive Mitochondrial Sequence Heteroplasmy in Natural Populations of Wild Carrot, Daucus carota spp. carota L. PLoS One 2015; 10:e0136303. [PMID: 26295342 PMCID: PMC4546501 DOI: 10.1371/journal.pone.0136303] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2015] [Accepted: 08/02/2015] [Indexed: 11/19/2022] Open
Abstract
Exceptions to the generally accepted rules that plant mitochondrial genomes are strictly maternally inherited and that within-individual sequence diversity in those genomes, i.e., heteroplasmy, should be minimal are becoming increasingly apparent especially with regard to sequence-level heteroplasmy. These findings raise questions about the potential significance of such heteroplasmy for plant mitochondrial genome evolution. Still studies quantifying the amount and consequences of sequence heteroplasmy in natural populations are rare. In this study, we report pervasive sequence heteroplasmy in natural populations of wild carrot, a close relative of the cultivated crop. In order to assay directly for this heteroplasmy, we implemented a quantitative PCR assay that can detect and quantify intra-individual SNP variation in two mitochondrial genes (Cox1 and Atp9). We found heteroplasmy in > 60% of all wild carrot populations surveyed and in > 30% of the 140 component individuals that were genotyped. Heteroplasmy ranged from a very small proportion of the total genotype (e.g., 0.995:0.005) to near even mixtures (e.g., 0.590:0.410) in some individuals. These results have important implications for the role of intra-genomic recombination in the generation of plant mitochondrial genome genotypic novelty. The consequences of such recombination are evident in the results of this study through analysis of the degree of linkage disequilibrium (LD) between the SNP sites at the two genes studied.
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50
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Havird JC, Hall MD, Dowling DK. The evolution of sex: A new hypothesis based on mitochondrial mutational erosion: Mitochondrial mutational erosion in ancestral eukaryotes would favor the evolution of sex, harnessing nuclear recombination to optimize compensatory nuclear coadaptation. Bioessays 2015. [PMID: 26201475 DOI: 10.1002/bies.201500057] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The evolution of sex in eukaryotes represents a paradox, given the "twofold" fitness cost it incurs. We hypothesize that the mutational dynamics of the mitochondrial genome would have favored the evolution of sexual reproduction. Mitochondrial DNA (mtDNA) exhibits a high-mutation rate across most eukaryote taxa, and several lines of evidence suggest that this high rate is an ancestral character. This seems inexplicable given that mtDNA-encoded genes underlie the expression of life's most salient functions, including energy conversion. We propose that negative metabolic effects linked to mitochondrial mutation accumulation would have invoked selection for sexual recombination between divergent host nuclear genomes in early eukaryote lineages. This would provide a mechanism by which recombinant host genotypes could be rapidly shuffled and screened for the presence of compensatory modifiers that offset mtDNA-induced harm. Under this hypothesis, recombination provides the genetic variation necessary for compensatory nuclear coadaptation to keep pace with mitochondrial mutation accumulation.
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Affiliation(s)
- Justin C Havird
- Deptartment of Biological Sciences, Auburn University, Auburn, AL, USA.,Department of Biology, Colorado State University, Fort Collins, CO, USA
| | - Matthew D Hall
- School of Biological Sciences, Monash University, Victoria, Australia
| | - Damian K Dowling
- School of Biological Sciences, Monash University, Victoria, Australia
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