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Fischer A, Dotzek J, Walther D, Greiner S. Graph-based models of the Oenothera mitochondrial genome capture the enormous complexity of higher plant mitochondrial DNA organization. NAR Genom Bioinform 2022; 4:lqac027. [PMID: 35372837 PMCID: PMC8969700 DOI: 10.1093/nargab/lqac027] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 03/02/2022] [Accepted: 03/09/2022] [Indexed: 12/26/2022] Open
Abstract
Plant mitochondrial genomes display an enormous structural complexity, as recombining repeat-pairs lead to the generation of various sub-genomic molecules, rendering these genomes extremely challenging to assemble. We present a novel bioinformatic data-processing pipeline called SAGBAC (Semi-Automated Graph-Based Assembly Curator) that identifies recombinogenic repeat-pairs and reconstructs plant mitochondrial genomes. SAGBAC processes assembly outputs and applies our novel ISEIS (Iterative Sequence Ends Identity Search) algorithm to obtain a graph-based visualization. We applied this approach to three mitochondrial genomes of evening primrose (Oenothera), a plant genus used for cytoplasmic genetics studies. All identified repeat pairs were found to be flanked by two alternative and unique sequence-contigs defining so-called 'double forks', resulting in four possible contig-repeat-contig combinations for each repeat pair. Based on the inferred structural models, the stoichiometry of the different contig-repeat-contig combinations was analyzed using Illumina mate-pair and PacBio RSII data. This uncovered a remarkable structural diversity of the three closely related mitochondrial genomes, as well as substantial phylogenetic variation of the underlying repeats. Our model allows predicting all recombination events and, thus, all possible sub-genomes. In future work, the proposed methodology may prove useful for the investigation of the sub-genome organization and dynamics in different tissues and at various developmental stages.
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Affiliation(s)
- Axel Fischer
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Jana Dotzek
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Dirk Walther
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Stephan Greiner
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
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2
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Liu H, Zhao W, Hua W, Liu J. A large-scale population based organelle pan-genomes construction and phylogeny analysis reveal the genetic diversity and the evolutionary origins of chloroplast and mitochondrion in Brassica napus L. BMC Genomics 2022; 23:339. [PMID: 35501686 PMCID: PMC9063048 DOI: 10.1186/s12864-022-08573-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 04/19/2022] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Allotetraploid oilseed rape (Brassica napus L.) is an important worldwide oil-producing crop. The origin of rapeseed is still undetermined due to the lack of wild resources. Despite certain genetic architecture and phylogenetic studies have been done focus on large group of Brassica nuclear genomes, the organelle genomes information under global pattern is largely unknown, which provide unique material for phylogenetic studies of B. napus. Here, based on de novo assemblies of 1,579 B. napus accessions collected globally, we constructed the chloroplast and mitochondrial pan-genomes of B. napus, and investigated the genetic diversity, phylogenetic relationships of B. napus, B. rapa and B. oleracea. RESULTS Based on mitotype-specific markers and mitotype-variant ORFs, four main cytoplasmic haplotypes were identified in our groups corresponding the nap, pol, ole, and cam mitotypes, among which the structure of chloroplast genomes was more conserved without any rearrangement than mitochondrial genomes. A total of 2,092 variants were detected in chloroplast genomes, whereas only 326 in mitochondrial genomes, indicating that chloroplast genomes exhibited a higher level of single-base polymorphism than mitochondrial genomes. Based on whole-genome variants diversity analysis, eleven genetic difference regions among different cytoplasmic haplotypes were identified on chloroplast genomes. The phylogenetic tree incorporating accessions of the B. rapa, B. oleracea, natural and synthetic populations of B. napus revealed multiple origins of B. napus cytoplasm. The cam-type and pol-type were both derived from B. rapa, while the ole-type was originated from B. oleracea. Notably, the nap-type cytoplasm was identified in both the B. rapa population and the synthetic B. napus, suggesting that B. rapa might be the maternal ancestor of nap-type B. napus. CONCLUSIONS The phylogenetic results provide novel insights into the organelle genomic evolution of Brassica species. The natural rapeseeds contained at least four cytoplastic haplotypes, of which the predominant nap-type might be originated from B. rapa. Besides, the organelle pan-genomes and the overall variation data offered useful resources for analysis of cytoplasmic inheritance related agronomical important traits of rapeseed, which can substantially facilitate the cultivation and improvement of rapeseed varieties.
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Affiliation(s)
- Hongfang Liu
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Wuhan, 430062, China
| | - Wei Zhao
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Wuhan, 430062, China
| | - Wei Hua
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Wuhan, 430062, China.
- Hubei Hongshan Laboratory, Wuhan, 430070, China.
| | - Jing Liu
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Wuhan, 430062, China.
- Hubei Hongshan Laboratory, Wuhan, 430070, China.
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Muliyar RK, Chowdappa P, Behera SK, Kasaragod S, Gangaraj KP, Kotimoole CN, Nekrakalaya B, Mohanty V, Sampgod RB, Banerjee G, Das AJ, Niral V, Karun A, Mahato AK, Gaikwad K, Singh NK, Prasad TSK. Assembly and Annotation of the Nuclear and Organellar Genomes of a Dwarf Coconut (Chowghat Green Dwarf) Possessing Enhanced Disease Resistance. OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2020; 24:726-742. [PMID: 33170083 DOI: 10.1089/omi.2020.0147] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Coconut (Cocos nucifera L.), an important source of vegetable oil, nutraceuticals, functional foods, and housing materials, provides raw materials for a repertoire of industries engaged in the manufacture of cosmetics, soaps, detergents, paints, varnishes, and emulsifiers, among other products. The palm plays a vital role in maintaining and promoting the sustainability of farming systems of the fragile ecosystems of islands and coastal regions of the tropics. In this study, we present the genome of a dwarf coconut variety "Chowghat Green Dwarf" (CGD) from India, possessing enhanced resistance to root (wilt) disease. Utilizing short reads from the Illumina HiSeq 4000 platform and long reads from the Pacific Biosciences RSII platform, we have assembled the draft genome assembly of 1.93 Gb. The genome is distributed over 26,855 scaffolds, with ∼81.56% of the assembled genome present in scaffolds of lengths longer than 50 kb. About 77.29% of the genome was composed of transposable elements and repeats. Gene prediction yielded 51,953 genes, which upon stringent filtering, based on Annotation Edit Distance, resulted in 13,707 genes, which coded for 11,181 proteins. Among these, we gathered transcript level evidence for a total of 6828 predicted genes based on the RNA-Seq data from different coconut tissues, since they presented assembled transcripts within the genome annotation coordinates. A total of 112 nucleotide-binding and leucine-rich repeat loci, belonging to six classes, were detected. We have also undertaken the assembly and annotation of the CGD chloroplast and mitochondrial genomes. The availability of the dwarf coconut genome shall prove invaluable for deducing the origin of dwarf coconut cultivars, dissection of genes controlling plant habit and fruit color, and accelerated breeding for improved agronomic traits.
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Affiliation(s)
| | - Pallem Chowdappa
- ICAR-Central Plantation Crops Research Institute (CPCRI), Kasaragod, India
| | - Santosh Kumar Behera
- Center for Systems Biology and Molecular Medicine, Yenepoya Research Centre, Yenepoya (Deemed to be University), Mangalore, India
| | - Sandeep Kasaragod
- Center for Systems Biology and Molecular Medicine, Yenepoya Research Centre, Yenepoya (Deemed to be University), Mangalore, India
| | | | - Chinmaya Narayana Kotimoole
- Center for Systems Biology and Molecular Medicine, Yenepoya Research Centre, Yenepoya (Deemed to be University), Mangalore, India
| | - Bhagya Nekrakalaya
- Center for Systems Biology and Molecular Medicine, Yenepoya Research Centre, Yenepoya (Deemed to be University), Mangalore, India
| | - Varshasnata Mohanty
- Center for Systems Biology and Molecular Medicine, Yenepoya Research Centre, Yenepoya (Deemed to be University), Mangalore, India
| | | | | | | | - Vittal Niral
- ICAR-Central Plantation Crops Research Institute (CPCRI), Kasaragod, India
| | - Anitha Karun
- ICAR-Central Plantation Crops Research Institute (CPCRI), Kasaragod, India
| | - Ajay Kumar Mahato
- ICAR-National Research Center on Plant Biotechnology, Pusa Campus, New Delhi, India
| | - Kishor Gaikwad
- ICAR-National Research Center on Plant Biotechnology, Pusa Campus, New Delhi, India
| | - Nagendra Kumar Singh
- ICAR-National Research Center on Plant Biotechnology, Pusa Campus, New Delhi, India
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Qiao J, Zhang X, Chen B, Huang F, Xu K, Huang Q, Huang Y, Hu Q, Wu X. Comparison of the cytoplastic genomes by resequencing: insights into the genetic diversity and the phylogeny of the agriculturally important genus Brassica. BMC Genomics 2020; 21:480. [PMID: 32660507 PMCID: PMC7359470 DOI: 10.1186/s12864-020-06889-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Accepted: 07/07/2020] [Indexed: 12/18/2022] Open
Abstract
Background The genus Brassica mainly comprises three diploid and three recently derived allotetraploid species, most of which are highly important vegetable, oil or ornamental crops cultivated worldwide. Despite being extensively studied, the origination of B. napus and certain detailed interspecific relationships within Brassica genus remains undetermined and somewhere confused. In the current high-throughput sequencing era, a systemic comparative genomic study based on a large population is necessary and would be crucial to resolve these questions. Results The chloroplast DNA and mitochondrial DNA were synchronously resequenced in a selected set of Brassica materials, which contain 72 accessions and maximally integrated the known Brassica species. The Brassica genomewide cpDNA and mtDNA variations have been identified. Detailed phylogenetic relationships inside and around Brassica genus have been delineated by the cpDNA- and mtDNA- variation derived phylogenies. Different from B. juncea and B. carinata, the natural B. napus contains three major cytoplasmic haplotypes: the cam-type which directly inherited from B. rapa, polima-type which is close to cam-type as a sister, and the mysterious but predominant nap-type. Certain sparse C-genome wild species might have primarily contributed the nap-type cytoplasm and the corresponding C subgenome to B. napus, implied by their con-clustering in both phylogenies. The strictly concurrent inheritance of mtDNA and cpDNA were dramatically disturbed in the B. napus cytoplasmic male sterile lines (e.g., mori and nsa). The genera Raphanus, Sinapis, Eruca, Moricandia show a strong parallel evolutional relationships with Brassica. Conclusions The overall variation data and elaborated phylogenetic relationships provide further insights into genetic understanding of Brassica, which can substantially facilitate the development of novel Brassica germplasms.
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Affiliation(s)
- Jiangwei Qiao
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan, China.
| | - Xiaojun Zhang
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan, China
| | - Biyun Chen
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan, China
| | | | - Kun Xu
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan, China
| | - Qian Huang
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan, China
| | - Yi Huang
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan, China
| | - Qiong Hu
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan, China
| | - Xiaoming Wu
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan, China
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5
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Liu J, Hao W, Liu J, Fan S, Zhao W, Deng L, Wang X, Hu Z, Hua W, Wang H. A Novel Chimeric Mitochondrial Gene Confers Cytoplasmic Effects on Seed Oil Content in Polyploid Rapeseed (Brassica napus). MOLECULAR PLANT 2019; 12:582-596. [PMID: 30703566 DOI: 10.1016/j.molp.2019.01.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 01/10/2019] [Accepted: 01/20/2019] [Indexed: 05/10/2023]
Abstract
Cytoplasmic effects (CEs) have been discovered to influence a diverse array of agronomic traits in crops, and understanding the underlying mechanisms can help accelerate breeding programs. Seed oil content (SOC) is of great agricultural, nutritional, and economic importance. However, the genetic basis of CEs on SOC (CE-SOC) remains enigmatic. In this study, we use an optimized approach to sequence the cytoplasmic (plastid and mitochondrial) genomes of allotetraploid oilseed rape (Brassica napus) cultivars, 51218 and 56366, that bear contrasting CE-SOC. By combining comparative genomics and genome-wide transcriptome analysis, we identify mitochondria-encoded orf188 as a potential CE-SOC determinant gene. Functional analyses in the model system Arabidopsis thaliana and rapeseed demonstrated that orf188 governs CE-SOC and could significantly increase SOC, strikingly, through promoting the yield of ATP. Consistent with this finding, transcriptional profiling with microarray and RNA sequencing revealed that orf188 affects transcriptional reprogramming of mitochondrial energy metabolism to facilitate ATP production. Intriguingly, orf188 is a previously uncharacterized chimeric gene, and the presence of this genetic novelty endows rapeseed with positive CE-SOC. Our results shed light on the molecular basis of CEs on a key quantitative trait in polyploid crops and enrich the theory of maternal control of oil content, providing new scientific guidance for breeding high-oil rapeseed germplasms.
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Affiliation(s)
- Jun Liu
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, China
| | - Wanjun Hao
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, China; Key Laboratory of Tea Biology and Resources Utilization, Ministry of Agriculture and Rural Affairs, Tea Research Institute of the Chinese Academy of Agricultural Sciences, Hangzhou 310008, China
| | - Jing Liu
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, China
| | - Shihang Fan
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, China
| | - Wei Zhao
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, China
| | - Linbing Deng
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, China
| | - Xinfa Wang
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, China
| | - Zhiyong Hu
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, China
| | - Wei Hua
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, China.
| | - Hanzhong Wang
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, China.
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6
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Li J, Zhang D, Ouyang K, Chen X. The complete chloroplast genome of the miracle tree Neolamarckia cadamba and its comparison in Rubiaceae family. BIOTECHNOL BIOTEC EQ 2018. [DOI: 10.1080/13102818.2018.1496034] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Affiliation(s)
- Jingjian Li
- College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, PR China
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangzhou, PR China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, Guangzhou, PR China
| | - Deng Zhang
- College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, PR China
| | - Kunxi Ouyang
- College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, PR China
| | - Xiaoyang Chen
- College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, PR China
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangzhou, PR China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, Guangzhou, PR China
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7
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Miller ME, Liberatore KL, Kianian SF. Optimization and Comparative Analysis of Plant Organellar DNA Enrichment Methods Suitable for Next-generation Sequencing. J Vis Exp 2017. [PMID: 28784941 DOI: 10.3791/55528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Plant organellar genomes contain large, repetitive elements that may undergo pairing or recombination to form complex structures and/or sub-genomic fragments. Organellar genomes also exist in admixtures within a given cell or tissue type (heteroplasmy), and an abundance of subtypes may change throughout development or when under stress (sub-stoichiometric shifting). Next-generation sequencing (NGS) technologies are required to obtain deeper understanding of organellar genome structure and function. Traditional sequencing studies use several methods to obtain organellar DNA: (1) If a large amount of starting tissue is used, it is homogenized and subjected to differential centrifugation and/or gradient purification. (2) If a smaller amount of tissue is used (i.e., if seeds, material, or space is limited), the same process is performed as in (1), followed by whole-genome amplification to obtain sufficient DNA. (3) Bioinformatics analysis can be used to sequence the total genomic DNA and to parse out organellar reads. All these methods have inherent challenges and tradeoffs. In (1), it may be difficult to obtain such a large amount of starting tissue; in (2), whole-genome amplification could introduce a sequencing bias; and in (3), homology between nuclear and organellar genomes could interfere with assembly and analysis. In plants with large nuclear genomes, it is advantageous to enrich for organellar DNA to reduce sequencing costs and sequence complexity for bioinformatics analyses. Here, we compare a traditional differential centrifugation method with a fourth method, an adapted CpG-methyl pulldown approach, to separate the total genomic DNA into nuclear and organellar fractions. Both methods yield sufficient DNA for NGS, DNA that is highly enriched for organellar sequences, albeit at different ratios in mitochondria and chloroplasts. We present the optimization of these methods for wheat leaf tissue and discuss major advantages and disadvantages of each approach in the context of sample input, protocol ease, and downstream application.
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Affiliation(s)
- Marisa E Miller
- Cereal Disease Laboratory, United States Department of Agriculture-Agricultural Research Service; Department of Horticultural Science, University of Minnesota
| | - Katie L Liberatore
- Cereal Disease Laboratory, United States Department of Agriculture-Agricultural Research Service; Department of Plant Pathology, University of Minnesota
| | - Shahryar F Kianian
- Cereal Disease Laboratory, United States Department of Agriculture-Agricultural Research Service; Department of Plant Pathology, University of Minnesota;
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8
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Li P, Zhang S, Li F, Zhang S, Zhang H, Wang X, Sun R, Bonnema G, Borm TJA. A Phylogenetic Analysis of Chloroplast Genomes Elucidates the Relationships of the Six Economically Important Brassica Species Comprising the Triangle of U. FRONTIERS IN PLANT SCIENCE 2017; 8:111. [PMID: 28210266 PMCID: PMC5288352 DOI: 10.3389/fpls.2017.00111] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2016] [Accepted: 01/19/2017] [Indexed: 05/20/2023]
Abstract
The Brassica genus comprises many economically important worldwide cultivated crops. The well-established model of the Brassica genus, U's triangle, consists of three basic diploid plant species (Brassica rapa, Brassica oleracea, and Brassica nigra) and three amphidiploid species (Brassica napus, Brassica juncea, and Brassica carinata) that arose through interspecific hybridizations. Despite being extensively studied because of its commercial relevance, several aspects of the origin of the Brassica species and the relationships within and among these six species still remain open questions. Here, we successfully de novo assembled 60 complete chloroplast genomes of Brassica genotypes of all six species. A complete map of the single nucleotide variants and insertions and deletions in the chloroplast genomes of different Brassica species was produced. The chloroplast genome consists of a Large and a Small Single Copy (LSC and SSC) region between two inverted repeats, and while these regions of chloroplast genomes have very different molecular evolutionary rates, phylogenetic analyses of different regions yielded no contradicting topologies and separated the Brassica genus into four clades. B. carinata and B. juncea share their chloroplast genome with one of their hybridization donors B. nigra and B. rapa, respectively, which fits the U model. B. rapa, surprisingly, shows evidence of two types of chloroplast genomes, with one type specific to some Italian broccoletto accessions. B. napus clearly has evidence for two independent hybridization events, as it contains either B. rapa chloroplast genomes. The divergence estimation suggests that B. nigra and B. carinata diverged from the main Brassica clade 13.7 million years ago (Mya), while B. rapa and B. oleracea diverged at 2.18 Mya. The use of the complete chloroplast DNA sequence not only provides insights into comparative genome analysis but also paves the way for a better understanding of the phylogenetic relationships within the Brassica genus.
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Affiliation(s)
- Peirong Li
- Chinese Cabbage Department, Institute of Vegetables and Flowers, Chinese Academy of Agricultural SciencesBeijing, China
- Plant Breeding, Wageningen University and ResearchWageningen, Netherlands
| | - Shujiang Zhang
- Chinese Cabbage Department, Institute of Vegetables and Flowers, Chinese Academy of Agricultural SciencesBeijing, China
| | - Fei Li
- Chinese Cabbage Department, Institute of Vegetables and Flowers, Chinese Academy of Agricultural SciencesBeijing, China
| | - Shifan Zhang
- Chinese Cabbage Department, Institute of Vegetables and Flowers, Chinese Academy of Agricultural SciencesBeijing, China
| | - Hui Zhang
- Chinese Cabbage Department, Institute of Vegetables and Flowers, Chinese Academy of Agricultural SciencesBeijing, China
| | - Xiaowu Wang
- Chinese Cabbage Department, Institute of Vegetables and Flowers, Chinese Academy of Agricultural SciencesBeijing, China
| | - Rifei Sun
- Chinese Cabbage Department, Institute of Vegetables and Flowers, Chinese Academy of Agricultural SciencesBeijing, China
- *Correspondence: Theo J. A. Borm, Guusje Bonnema, Rifei Sun,
| | - Guusje Bonnema
- Plant Breeding, Wageningen University and ResearchWageningen, Netherlands
- *Correspondence: Theo J. A. Borm, Guusje Bonnema, Rifei Sun,
| | - Theo J. A. Borm
- Plant Breeding, Wageningen University and ResearchWageningen, Netherlands
- *Correspondence: Theo J. A. Borm, Guusje Bonnema, Rifei Sun,
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9
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Wang WC, Chen SY, Zhang XZ. Chloroplast Genome Evolution in Actinidiaceae: clpP Loss, Heterogenous Divergence and Phylogenomic Practice. PLoS One 2016; 11:e0162324. [PMID: 27589600 PMCID: PMC5010200 DOI: 10.1371/journal.pone.0162324] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Accepted: 08/19/2016] [Indexed: 12/13/2022] Open
Abstract
Actinidiaceae is a well-known economically important plant family in asterids. To elucidate the chloroplast (cp) genome evolution within this family, here we present complete genomes of three species from two sister genera (Clematoclethra and Actinidia) in the Actinidiaceae via genome skimming technique. Comparative analyses revealed that the genome structure and content were rather conservative in three cp genomes in spite of different inheritance pattern, i.e.paternal in Actinidia and maternal in Clematoclethra. The clpP gene was lacked in all the three sequenced cp genomes examined here indicating that the clpP gene loss is likely a conspicuous synapomorphic characteristic during the cp genome evolution of Actinidiaceae. Comprehensive sequence comparisons in Actinidiaceae cp genomes uncovered that there were apparently heterogenous divergence patterns among the cpDNA regions, suggesting a preferred data-partitioned analysis for cp phylogenomics. Twenty non-coding cpDNA loci with fast evolutionary rates are further identified as potential molecular markers for systematics studies of Actinidiaceae. Moreover, the cp phylogenomic analyses including 31 angiosperm plastomes strongly supported the monophyly of Actinidia, being sister to Clematoclethra in Actinidiaceae which locates in the basal asterids, Ericales.
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Affiliation(s)
- Wen-Cai Wang
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, United Kingdom
| | - Si-Yun Chen
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Xian-Zhi Zhang
- College of Forestry, Northwest A&F University, Yangling, Shaanxi, China
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