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Wang YW, Elmore H, Pringle A. Uniparental Inheritance and Recombination as Strategies to Avoid Competition and Combat Muller's Ratchet among Mitochondria in Natural Populations of the Fungus Amanita phalloides. J Fungi (Basel) 2023; 9:476. [PMID: 37108928 PMCID: PMC10142858 DOI: 10.3390/jof9040476] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 04/03/2023] [Accepted: 04/13/2023] [Indexed: 04/29/2023] Open
Abstract
Uniparental inheritance of mitochondria enables organisms to avoid the costs of intracellular competition among potentially selfish organelles. By preventing recombination, uniparental inheritance may also render a mitochondrial lineage effectively asexual and expose mitochondria to the deleterious effects of Muller's ratchet. Even among animals and plants, the evolutionary dynamics of mitochondria remain obscure, and less is known about mitochondrial inheritance among fungi. To understand mitochondrial inheritance and test for mitochondrial recombination in one species of filamentous fungus, we took a population genomics approach. We assembled and analyzed 88 mitochondrial genomes from natural populations of the invasive death cap Amanita phalloides, sampling from both California (an invaded range) and Europe (its native range). The mitochondrial genomes clustered into two distinct groups made up of 57 and 31 mushrooms, but both mitochondrial types are geographically widespread. Multiple lines of evidence, including negative correlations between linkage disequilibrium and distances between sites and coalescent analysis, suggest low rates of recombination among the mitochondria (ρ = 3.54 × 10-4). Recombination requires genetically distinct mitochondria to inhabit a cell, and recombination among A. phalloides mitochondria provides evidence for heteroplasmy as a feature of the death cap life cycle. However, no mushroom houses more than one mitochondrial genome, suggesting that heteroplasmy is rare or transient. Uniparental inheritance emerges as the primary mode of mitochondrial inheritance, even as recombination appears as a strategy to alleviate Muller's ratchet.
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Affiliation(s)
- Yen-Wen Wang
- Department of Botany, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Holly Elmore
- Rethink Priorities, San Francisco, CA 94117, USA
| | - Anne Pringle
- Department of Botany, University of Wisconsin-Madison, Madison, WI 53706, USA
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA
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Li H, Xu J, Wang S, Wang P, Rao W, Hou B, Zhang Y. Genetic Differentiation and Widespread Mitochondrial Heteroplasmy among Geographic Populations of the Gourmet Mushroom Thelephora ganbajun from Yunnan, China. Genes (Basel) 2022; 13:genes13050854. [PMID: 35627240 PMCID: PMC9141859 DOI: 10.3390/genes13050854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 05/06/2022] [Accepted: 05/08/2022] [Indexed: 11/30/2022] Open
Abstract
The mitochondrial genomes are generally considered non-recombining and homoplasmic in nature. However, our previous study provided the first evidence of extensive and stable mitochondrial heteroplasmy in natural populations of the basidiomycete fungus Thelephora ganbajun from Yunnan province, China. The heteroplasmy was characterized by the presence of two types of introns residing at adjacent but different sites in the cytochrome oxidase subunits I (cox1) gene within an individual strain. However, the frequencies of these two introns among isolates from different geographical populations and the implications for the genetic structure in natural populations have not been investigated. In this study, we analyzed DNA sequence variation at the internal transcribed spacer (ITS) regions of the nuclear ribosomal RNA gene cluster among 489 specimens from 30 geographic locations from Yunnan and compared that variation with distribution patterns of the two signature introns in the cox1 gene that are indicative of heteroplasmy in this species. In our samples, evidence for gene flow, abundant genetic diversity, and genotypic uniqueness among geographic samples in Yunnan were revealed by ITS sequence variation. While there was insignificant positive correlation between geographic distance and genetic differentiation among the geographic samples based on ITS sequences, a moderate significant correlation was found between ITS sequence variation, geographical distance of sampling sites, and distribution patterns of the two heteroplasmic introns in the cox1 gene. Interestingly, there was a significantly negative correlation between the copy numbers of the two co-existing introns. We discussed the implications of our results for a better understanding of the spread of stable mitochondrial heteroplasmy, mito-nuclear interactions, and conservation of this important gourmet mushroom.
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Affiliation(s)
- Haixia Li
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming 650032, China; (H.L.); (J.X.); (S.W.); (P.W.)
- School of Life Science, Yunnan University, Kunming 650032, China; (W.R.); (B.H.)
| | - Jianping Xu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming 650032, China; (H.L.); (J.X.); (S.W.); (P.W.)
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Shaojuan Wang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming 650032, China; (H.L.); (J.X.); (S.W.); (P.W.)
- School of Life Science, Yunnan University, Kunming 650032, China; (W.R.); (B.H.)
| | - Pengfei Wang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming 650032, China; (H.L.); (J.X.); (S.W.); (P.W.)
| | - Wanqin Rao
- School of Life Science, Yunnan University, Kunming 650032, China; (W.R.); (B.H.)
| | - Bin Hou
- School of Life Science, Yunnan University, Kunming 650032, China; (W.R.); (B.H.)
| | - Ying Zhang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming 650032, China; (H.L.); (J.X.); (S.W.); (P.W.)
- Correspondence:
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Population genomic analyses reveal evidence for limited recombination in the superbug Candida auris in nature. Comput Struct Biotechnol J 2022; 20:3030-3040. [PMID: 35782746 PMCID: PMC9218166 DOI: 10.1016/j.csbj.2022.06.030] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 06/11/2022] [Accepted: 06/12/2022] [Indexed: 11/22/2022] Open
Abstract
Candida auris is a recently emerged, multidrug-resistant pathogenic yeast capable of causing a diversity of human infections worldwide. Genetic analyses based on whole-genome sequences have clustered strains in this species into five divergent clades, with each clade containing limited genetic variation and one of two mating types, MTLa or MTLα. The patterns of genetic variations suggest simultaneous emergence and clonal expansion of multiple clades of this pathogen across the world. At present, it is unclear whether recombination has played any role during the evolution of C. auris. In this study, we analyzed patterns of associations among single nucleotide polymorphisms in both the nuclear and the mitochondrial genomes of 1,285 strains to investigate potential signatures of recombination in natural C. auris populations. Overall, we found that polymorphisms in the nuclear and mitochondrial genomes clustered the strains similarly into the five clades, consistent with a lack of evidence for recombination among the clades after their divergence. However, variable percentages of SNP pairs showed evidence of phylogenetic incompatibility and linkage equilibrium among samples in both the nuclear and the mitochondrial genomes, with the percentages higher in the total population than those within individual clades. Our results are consistent with limited but greater frequency of recombination before the divergence of the clades than afterwards. SNPs at loci related to antifungal resistance showed frequencies of recombination similar to or lower than those observed for SNPs in other parts of the genome. Together, though very limited, evidence for the observed recombination for both before and after the divergence of the clades suggests the possibility for continuous genetic exchange in natural populations of this important yeast pathogen.
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Xu J. Is Natural Population of Candida tropicalis Sexual, Parasexual, and/or Asexual? Front Cell Infect Microbiol 2021; 11:751676. [PMID: 34760719 PMCID: PMC8573272 DOI: 10.3389/fcimb.2021.751676] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Accepted: 10/12/2021] [Indexed: 01/04/2023] Open
Abstract
Candida tropicalis is one of the most common opportunistic yeast pathogens of humans, especially prevalent in tropical and subtropical regions. This yeast has broad ecological distributions, can be found in both terrestrial and aquatic ecosystems, including being associated with a diversity of trees, animals, and humans. Evolutionary theory predicts that organisms thriving in diverse ecological niches likely have efficient mechanisms to generate genetic diversity in nature. Indeed, abundant genetic variations have been reported in natural populations (both environmental and clinical) of C. tropicalis. However, at present, our understanding on how genetic diversity is generated in natural C. tropicalis population remains controversial. In this paper, I review the current understanding on the potential modes of reproduction in C. tropicalis. I describe expectations of the three modes of reproduction (sexual, parasexual, and asexual) and compare them with the observed genotypic variations in natural populations. Though sexual and parasexual reproduction cannot be excluded, the analyses suggest asexual reproduction alone could explain all the observations reported so far. The results here have implications for understanding the evolution and epidemiology of C. tropicalis and other related human fungal pathogens.
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Affiliation(s)
- Jianping Xu
- Institute of Bast Fiber Crops and Center of Southern Economic Crops, Chinese Academy of Agricultural Sciences, Changsha, China.,Department of Biology, McMaster University, Hamilton, ON, Canada
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Zhang Y, Wang S, Li H, Liu C, Mi F, Wang R, Mo M, Xu J. Evidence for Persistent Heteroplasmy and Ancient Recombination in the Mitochondrial Genomes of the Edible Yellow Chanterelles From Southwestern China and Europe. Front Microbiol 2021; 12:699598. [PMID: 34335532 PMCID: PMC8317506 DOI: 10.3389/fmicb.2021.699598] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 06/23/2021] [Indexed: 11/13/2022] Open
Abstract
Mitochondrial genes and genomes have patterns of inheritance that are distinctly different from those of nuclear genes and genomes. In nature, the mitochondrial genomes in eukaryotes are generally considered non-recombining and homoplasmic. If heteroplasmy and recombination exist, they are typically very limited in both space and time. Here we show that mitochondrial heteroplasmy and recombination may not be limited to a specific population nor exit only transiently in the basidiomycete Cantharellus cibarius and related species. These edible yellow chanterelles are an ecologically very important group of fungi and among the most prominent wild edible mushrooms in the Northern Hemisphere. At present, very little is known about the genetics and population biology of these fungia cross large geographical distances. Our study here analyzed a total of 363 specimens of edible yellow chanterelles from 24 geographic locations in Yunnan in southwestern China and six geographic locations in five countries in Europe. For each mushroom sample, we obtained the DNA sequences at two genes, one in the nuclear genome and one in the mitochondrial genome. Our analyses of the nuclear gene, translation elongation factor 1-alpha (tef-1) and the DNA barcode of C. cibarius and related species, suggested these samples belong to four known species and five potential new species. Interestingly, analyses of the mitochondrial ATP synthase subunit 6 (atp6) gene fragment revealed evidence of heteroplasmy in two geographic samples in Yunnan and recombination within the two new putative species in Yunnan. Specifically, all four possible haplotypes at two polymorphic nucleotide sites within the mitochondrial atp6 gene were found distributed across several geographic locations in Yunnan. Furthermore, these four haplotypes were broadly distributed across multiple phylogenetic clades constructed based on nuclear tef-1 sequences. Our results suggest that heteroplasmy and mitochondrial recombination might have happened repeatedly during the evolution of the yellow chanterelles. Together, our results suggest that the edible yellow chanterelles represent an excellent system from which to study the evolution of mitochondrial-nuclear genome relationships.
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Affiliation(s)
- Ying Zhang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, Yunnan University, Kunming, China
| | - Shaojuan Wang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, Yunnan University, Kunming, China
- School of Life Sciences, Yunnan University, Kunming, China
- Qicai Yunnan Primary School Affiliated with Yunnan Normal University, Kunming, China
| | - Haixia Li
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, Yunnan University, Kunming, China
- School of Life Sciences, Yunnan University, Kunming, China
| | - Chunli Liu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, Yunnan University, Kunming, China
- Kunming Edible Fungi Institute of All-China Federation of Supply and Marketing Cooperatives, Kunming, China
| | - Fei Mi
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, Yunnan University, Kunming, China
- Research Institute of Nutrition and Food Science, Kunming Medical University, Kunming, China
| | - Ruirui Wang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, Yunnan University, Kunming, China
- School of Life Sciences, Yunnan University, Kunming, China
| | - Meizi Mo
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, Yunnan University, Kunming, China
- School of Life Sciences, Yunnan University, Kunming, China
| | - Jianping Xu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, Yunnan University, Kunming, China
- Department of Biology, McMaster University, Hamilton, ON, Canada
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Deng Y, Zhang X, Xie B, Lin L, Hsiang T, Lin X, Lin Y, Zhang X, Ma Y, Miao W, Ming R. Intra-specific comparison of mitochondrial genomes reveals host gene fragment exchange via intron mobility in Tremella fuciformis. BMC Genomics 2020; 21:426. [PMID: 32580700 PMCID: PMC7315562 DOI: 10.1186/s12864-020-06846-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 06/17/2020] [Indexed: 01/21/2023] Open
Abstract
Background Mitochondrial genomic sequences are known to be variable. Comparative analyses of mitochondrial genomes can reveal the nature and extent of their variation. Results Draft mitochondrial genomes of 16 Tremella fuciformis isolates (TF01-TF16) were assembled from Illumina and PacBio sequencing data. Mitochondrial DNA contigs were extracted and assembled into complete circular molecules, ranging from 35,104 bp to 49,044 bp in size. All mtDNAs contained the same set of 41 conserved genes with identical gene order. Comparative analyses revealed that introns and intergenic regions were variable, whereas genic regions (including coding sequences, tRNA, and rRNA genes) were conserved. Among 24 introns detected, 11 were in protein-coding genes, 3 in tRNA genes, and the other 10 in rRNA genes. In addition, two mobile fragments were found in intergenic regions. Interestingly, six introns containing N-terminal duplication of the host genes were found in five conserved protein-coding gene sequences. Comparison of genes with and without these introns gave rise to the following proposed model: gene fragment exchange with other species can occur via gain or loss of introns with N-terminal duplication of the host genes. Conclusions Our findings suggest a novel mechanism of fungal mitochondrial gene evolution: partial foreign gene replacement though intron mobility.
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Affiliation(s)
- Youjin Deng
- Center for Genomics and Biotechnology, Haixia Institute of Science and Technology, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.,Department of Plant Biology, University of Illinois at Urbana-Champaign, 1201 W. Gregory Drive, Urbana, IL, 61801, USA
| | - Xunxiao Zhang
- Center for Genomics and Biotechnology, Haixia Institute of Science and Technology, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Baogui Xie
- Center for Genomics and Biotechnology, Haixia Institute of Science and Technology, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Longji Lin
- Center for Genomics and Biotechnology, Haixia Institute of Science and Technology, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Tom Hsiang
- Environmental Sciences, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Xiangzhi Lin
- Center for Genomics and Biotechnology, Haixia Institute of Science and Technology, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Yiying Lin
- Center for Genomics and Biotechnology, Haixia Institute of Science and Technology, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Xingtan Zhang
- Center for Genomics and Biotechnology, Haixia Institute of Science and Technology, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Yanhong Ma
- Center for Genomics and Biotechnology, Haixia Institute of Science and Technology, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Wenjing Miao
- Center for Genomics and Biotechnology, Haixia Institute of Science and Technology, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Ray Ming
- Center for Genomics and Biotechnology, Haixia Institute of Science and Technology, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China. .,Department of Plant Biology, University of Illinois at Urbana-Champaign, 1201 W. Gregory Drive, Urbana, IL, 61801, USA.
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7
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Lee HH, Ke HM, Lin CYI, Lee TJ, Chung CL, Tsai IJ. Evidence of Extensive Intraspecific Noncoding Reshuffling in a 169-kb Mitochondrial Genome of a Basidiomycetous Fungus. Genome Biol Evol 2020; 11:2774-2788. [PMID: 31418013 PMCID: PMC6786477 DOI: 10.1093/gbe/evz181] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/13/2019] [Indexed: 12/19/2022] Open
Abstract
Comparative genomics of fungal mitochondrial genomes (mitogenomes) have revealed a remarkable pattern of rearrangement between and within major phyla owing to horizontal gene transfer and recombination. The role of recombination was exemplified at a finer evolutionary time scale in basidiomycetes group of fungi as they display a diversity of mitochondrial DNA inheritance patterns. Here, we assembled mitogenomes of six species from the Hymenochaetales order of basidiomycetes and examined 59 mitogenomes from 2 genetic lineages of Phellinus noxius. Gene order is largely collinear, while intergene regions are major determinants of mitogenome size variation. Substantial sequence divergence was found in shared introns consistent with high horizontal gene transfer frequency observed in yeasts, but we also identified a rare case where an intron was retained in five species since speciation. In contrast to the hyperdiversity observed in nuclear genomes of Phellinus noxius, mitogenomes’ intraspecific polymorphisms at protein-coding sequences are extremely low. Phylogeny network based on introns revealed turnover as well as exchange of introns between two lineages. Strikingly, some strains harbor a mosaic origin of introns from both lineages. Analysis of intergenic sequence indicated substantial differences between and within lineages, and an expansion may be ongoing as a result of exchange between distal intergenes. These findings suggest that the evolution in mitochondrial DNAs is usually lineage specific but chimeric mitotypes are frequently observed, thus capturing the possible evolutionary processes shaping mitogenomes in a basidiomycete. The large mitogenome sizes reported in various basidiomycetes appear to be a result of interspecific reshuffling of intergenes.
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Affiliation(s)
- Hsin-Han Lee
- Biodiversity Research Center, Academia Sinica, Taipei City, Taiwan
| | - Huei-Mien Ke
- Biodiversity Research Center, Academia Sinica, Taipei City, Taiwan
| | - Chan-Yi Ivy Lin
- Biodiversity Research Center, Academia Sinica, Taipei City, Taiwan
| | - Tracy J Lee
- Biodiversity Research Center, Academia Sinica, Taipei City, Taiwan.,Biodiversity Program, Taiwan International Graduate Program, Academia Sinica and National Taiwan Normal University, Taipei City, Taiwan.,Department of Life Science, National Taiwan Normal University, Taipei City, Taiwan
| | - Chia-Lin Chung
- Department of Plant Pathology and Microbiology, National Taiwan University, Taipei City, Taiwan
| | - Isheng J Tsai
- Biodiversity Research Center, Academia Sinica, Taipei City, Taiwan
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Nieuwenhuis M, van de Peppel LJJ, Bakker FT, Zwaan BJ, Aanen DK. Enrichment of G4DNA and a Large Inverted Repeat Coincide in the Mitochondrial Genomes of Termitomyces. Genome Biol Evol 2019; 11:1857-1869. [PMID: 31209489 PMCID: PMC6609731 DOI: 10.1093/gbe/evz122] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/11/2019] [Indexed: 12/20/2022] Open
Abstract
Mitochondria retain their own genome, a hallmark of their bacterial ancestry. Mitochondrial genomes (mtDNA) are highly diverse in size, shape, and structure, despite their conserved function across most eukaryotes. Exploring extreme cases of mtDNA architecture can yield important information on fundamental aspects of genome biology. We discovered that the mitochondrial genomes of a basidiomycete fungus (Termitomyces spp.) contain an inverted repeat (IR), a duplicated region half the size of the complete genome. In addition, we found an abundance of sequences capable of forming G-quadruplexes (G4DNA); structures that can disrupt the double helical formation of DNA. G4DNA is implicated in replication fork stalling, double-stranded breaks, altered gene expression, recombination, and other effects. To determine whether this occurrence of IR and G4DNA was correlated within the genus Termitomyces, we reconstructed the mitochondrial genomes of 11 additional species including representatives of several closely related genera. We show that the mtDNA of all sampled species of Termitomyces and its sister group, represented by the species Tephrocybe rancida and Blastosporella zonata, are characterized by a large IR and enrichment of G4DNA. To determine whether high mitochondrial G4DNA content is common in fungi, we conducted the first broad survey of G4DNA content in fungal mtDNA, revealing it to be a highly variable trait. The results of this study provide important direction for future research on the function and evolution of G4DNA and organellar IRs.
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Affiliation(s)
| | | | - Freek T Bakker
- Biosystematics Group, Wageningen University & Research, The Netherlands
| | - Bas J Zwaan
- Laboratory of Genetics, Wageningen University & Research, The Netherlands
| | - Duur K Aanen
- Laboratory of Genetics, Wageningen University & Research, The Netherlands
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Fungal mitochondrial genomes and genetic polymorphisms. Appl Microbiol Biotechnol 2018; 102:9433-9448. [PMID: 30209549 DOI: 10.1007/s00253-018-9350-5] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 08/24/2018] [Accepted: 08/27/2018] [Indexed: 12/24/2022]
Abstract
Mitochondria are the powerhouses of eukaryotic cells, responsible for ATP generation and playing a role in a diversity of cellular and organismal functions. Different from the majority of other intracellular membrane structures, mitochondria contain their own genetic materials that are capable of independent replication and inheritance. In this mini-review, we provide brief summaries of fungal mitochondrial genome structure, size, gene content, inheritance, and genetic variation. We pay special attention to the relative genetic polymorphisms of the mitochondrial vs nuclear genomes at the population level within individual fungal species. Among the 20 species/groups of species reviewed here, there is a range of variation among genes and species in the relative nuclear and mitochondrial genetic polymorphisms. Interestingly, most (15/20) showed a greater genetic diversity for nuclear genes and genomes than for mitochondrial genes and genomes, with the remaining five showing similar or slower nuclear genome genetic variations. This fungal pattern is different from the dominant pattern in animals, but more similar to that in plants. At present, the mechanisms for the variations among fungal species and the overall low level of mitochondrial sequence polymorphisms are not known. The increasing availability of population genomic data should help us reveal the potential genetic and ecological factors responsible for the observed variations.
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Frequent heteroplasmy and recombination in the mitochondrial genomes of the basidiomycete mushroom Thelephora ganbajun. Sci Rep 2017; 7:1626. [PMID: 28487526 PMCID: PMC5431624 DOI: 10.1038/s41598-017-01823-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 03/31/2017] [Indexed: 12/16/2022] Open
Abstract
In the majority of sexual eukaryotes, the mitochondrial genomes are inherited uniparentally. As a result, individual organisms are homoplasmic, containing mitochondrial DNA (mtDNA) from a single parent. Here we analyzed the mitochondrial genotypes in Clade I of the gourmet mushroom Thelephora ganbajun from its broad geographic distribution range. A total of 299 isolates from 28 geographic locations were sequenced at three mitochondrial loci: the mitochondrial small ribosomal RNA gene, and the cytochrome c oxidase subunits I (COX1) and III (COX3) genes. Quantitative PCR analyses showed that the strains had about 60–160 copies of mitochondrial genomes per cell. Interestingly, while no evidence of heteroplasmy was found at the 12S rRNA gene, 262 of the 299 isolates had clear evidence of heterogeneity at either the COX1 (261 isolates) or COX3 (12 isolates) gene fragments. The COX1 heteroplasmy was characterized by two types of introns residing at different sites of the same region and at different frequencies among the isolates. Allelic association analyses of the observed mitochondrial polymorphic nucleotide sites suggest that mtDNA recombination is common in natural populations of this fungus. Our results contrast the prevailing view that heteroplasmy, if exists, is only transient in basidiomycete fungi.
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12
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Wang Z, Wilson A, Xu J. Mitochondrial DNA inheritance in the human fungal pathogen Cryptococcus gattii. Fungal Genet Biol 2015; 75:1-10. [DOI: 10.1016/j.fgb.2015.01.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 12/18/2014] [Accepted: 01/02/2015] [Indexed: 01/19/2023]
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13
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Kerrigan RW, Challen MP, Burton KS. Agaricus bisporus genome sequence: a commentary. Fungal Genet Biol 2013; 55:2-5. [PMID: 23558250 DOI: 10.1016/j.fgb.2013.03.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Revised: 03/17/2013] [Accepted: 03/22/2013] [Indexed: 11/19/2022]
Abstract
The genomes of two isolates of Agaricus bisporus have been sequenced recently. This soil-inhabiting fungus has a wide geographical distribution in nature and it is also cultivated in an industrialized indoor process ($4.7bn annual worldwide value) to produce edible mushrooms. Previously this lignocellulosic fungus has resisted precise econutritional classification, i.e. into white- or brown-rot decomposers. The generation of the genome sequence and transcriptomic analyses has revealed a new classification, 'humicolous', for species adapted to grow in humic-rich, partially decomposed leaf material. The Agaricus biporus genomes contain a collection of polysaccharide and lignin-degrading genes and more interestingly an expanded number of genes (relative to other lignocellulosic fungi) that enhance degradation of lignin derivatives, i.e. heme-thiolate peroxidases and β-etherases. A motif that is hypothesized to be a promoter element in the humicolous adaptation suite is present in a large number of genes specifically up-regulated when the mycelium is grown on humic-rich substrate. The genome sequence of A. bisporus offers a platform to explore fungal biology in carbon-rich soil environments and terrestrial cycling of carbon, nitrogen, phosphorus and potassium.
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