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Wang H, Wu Z, Li T, Zhao J. Highly active repeat-mediated recombination in the mitogenome of the aquatic grass Hygroryza aristata. BMC PLANT BIOLOGY 2024; 24:644. [PMID: 38973002 PMCID: PMC11229283 DOI: 10.1186/s12870-024-05331-x] [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: 03/26/2024] [Accepted: 06/24/2024] [Indexed: 07/09/2024]
Abstract
BACKGROUND Floating bamboo (Hygroryza aristata) is an endangered species with a narrow native distribution and is renowned for its unique aesthetic qualities, which holds significant ecological and ornamental value. However, the lack of genetic information research, with only one complete plastome available, significantly hampers conservation efforts and further research for this species. RESULTS In this research, we sequenced and assembled the organelle genomes of floating bamboo, including the mitogenome (587,847 bp) and plastome (135,675 bp). The mitogenome can recombine into various configurations, which are mediated by 25 repeat pairs (13 SRs, 6 MRs, 1 LR, and 5 CRs). LR1 and SR5 are particularly notable as they have the ability to combine with other contigs, forming complex repeat units that facilitate further homologous recombination. The rate of homologous recombination varies significantly among species, yet there is still a pronounced positive correlation observed between the length of these repeat pairs and the rate of recombination they mediate. The mitogenome integrates seven intact protein-coding genes from the chloroplast. The codon usage patterns in both organelles are similar, with a noticeable bias towards C and T on the third codon. The gene map of Poales shows the entire loss of rpl6, succinate dehydrogenase subunits (sdh3 and sdh4). Additionally, the BOP clade retained more variable genes compared to the PACMAD clade. CONCLUSIONS We provided a high-quality and well-annotated mitogenome for floating bamboo and demonstrated the presence of diverse configurations. Our study has revealed the correlation between repeat length and their corresponding recombination rate despite variations among species. Although the mitogenome can potentially exist in the form of a unicircular in vivo, this occurrence is rare and may not be stable.
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Affiliation(s)
- Huijun Wang
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Zhigang Wu
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.
- University of Chinese Academy of Sciences, Beijing, China.
| | - Tao Li
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.
- University of Chinese Academy of Sciences, Beijing, China.
| | - Jindong Zhao
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- State Key Laboratory of Protein and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing, China
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Shan Y, Li J, Duan X, Zhang X, Yu J. Elucidating the multichromosomal structure within the Brasenia schreberi mitochondrial genome through assembly and analysis. BMC Genomics 2024; 25:422. [PMID: 38684976 PMCID: PMC11059650 DOI: 10.1186/s12864-024-10331-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 04/22/2024] [Indexed: 05/02/2024] Open
Abstract
Brasenia schreberi, a plant species traditionally utilized in Chinese medicine and cuisine, represents an early evolutionary stage among flowering plants (angiosperms). While the plastid genome of this species has been published, its mitochondrial genome (mitogenome) has not been extensively explored, with a notable absence of thorough comparative analyses of its organellar genomes. In our study, we had assembled the entire mitogenome of B. schreberi utilizing the sequencing data derived from both Illumina platform and Oxford Nanopore. The B. schreberi mitogenome mostly exists as six circular DNA molecules, with the largest being 628,257 base pairs (bp) and the smallest 110,220 bp, amounting to 1.49 megabases (Mb). Then we annotated the mitogenome of B. schreberi. The mitogenome encompasses a total of 71 genes: 40 of these are coding proteins genes (PCGs), 28 are genes for transfer RNA (tRNA), and the remaining 3 are genes for ribosomal RNA (rRNA). In the analysis of codon usage, we noted a unique codon preference specific to each amino acid. The most commonly used codons exhibited an average RSCU of 1.36, indicating a noticeable bias in codon selection. In the repeat sequence analysis, a total of 553 simple sequence repeats (SSRs) were identified, 1,822 dispersed repeats (comprising 1,015 forward and 807 palindromic repeats), and 608 long terminal repeats (LTRs). Additionally, in the analysis of homologous sequences between organelle genomes, we detected 38 homologous sequences derived from the plastid genome, each exceeding 500 bp, within the B. schreberi mitochondrial genome. Notably, ten tRNA genes (trnC-GCA, trnM-CAU, trnI-CAU, trnQ-UUG, trnN-GUU, trnT-GGU, trnW-CCA, trnA-UGC, trnI-GAU, and trnV-GAC) appear to have been completely transferred from the chloroplast to the mitogenome. Utilizing the Deepred-mt to predict the RNA editing sites in the mitogenome, we have identified 675 high-quality RNA editing sites in the 40 mitochondrial PCGs. In the final stage of our study, we performed an analysis of colinearity and inferred the phylogenetic relationship of B. schreberi with other angiosperms, utilizing the mitochondrial PCGs as a basis. The results showed that the non-coding regions of the B. schreberi mitogenome are characterized by an abundance of repetitive sequences and exogenous sequences, and B. schreberi is more closely related with Euryale ferox.
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Affiliation(s)
- Yuanyu Shan
- College of Horticulture and Landscape Architecture, Southwest University, Chongqing, 400716, China
| | - Jingling Li
- College of Horticulture and Landscape Architecture, Southwest University, Chongqing, 400716, China
| | - Xinmei Duan
- College of Horticulture and Landscape Architecture, Southwest University, Chongqing, 400716, China
| | - Xue Zhang
- College of Horticulture and Landscape Architecture, Southwest University, Chongqing, 400716, China
| | - Jie Yu
- College of Horticulture and Landscape Architecture, Southwest University, Chongqing, 400716, China.
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), Southwest University, Chongqing, 400715, China.
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Li J, Li J, Ma Y, Kou L, Wei J, Wang W. The complete mitochondrial genome of okra (Abelmoschus esculentus): using nanopore long reads to investigate gene transfer from chloroplast genomes and rearrangements of mitochondrial DNA molecules. BMC Genomics 2022; 23:481. [PMID: 35768783 PMCID: PMC9245263 DOI: 10.1186/s12864-022-08706-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 06/13/2022] [Indexed: 12/12/2022] Open
Abstract
Background Okra (Abelmoschus esculentus L. Moench) is an economically important crop and is known for its slimy juice, which has significant scientific research value. The A. esculentus chloroplast genome has been reported; however, the sequence of its mitochondrial genome is still lacking. Results We sequenced the plastid and mitochondrial genomes of okra based on Illumina short reads and Nanopore long reads and conducted a comparative study between the two organelle genomes. The plastid genome of okra is highly structurally conserved, but the mitochondrial genome of okra has been confirmed to have abundant subgenomic configurations. The assembly results showed that okra’s mitochondrial genome existed mainly in the form of two independent molecules, which could be divided into four independent molecules through two pairs of long repeats. In addition, we found that four pairs of short repeats could mediate the integration of the two independent molecules into one complete molecule at a low frequency. Subsequently, we also found extensive sequence transfer between the two organelles of okra, where three plastid-derived genes (psaA, rps7 and psbJ) remained intact in the mitochondrial genome. Furthermore, psbJ, psbF, psbE and psbL were integrated into the mitochondrial genome as a conserved gene cluster and underwent pseudogenization as nonfunctional genes. Only psbJ retained a relatively complete sequence, but its expression was not detected in the transcriptome data, and we speculate that it is still nonfunctional. Finally, we characterized the RNA editing events of protein-coding genes located in the organelle genomes of okra. Conclusions In the current study, our results not only provide high-quality organelle genomes for okra but also advance our understanding of the gene dialogue between organelle genomes and provide information to breed okra cultivars efficiently. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-022-08706-2.
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Affiliation(s)
- Jihan Li
- College of Horticulture and Landscape Architecture, Southwest University, Chongqing, 400716, China
| | - Jingling Li
- College of Horticulture and Landscape Architecture, Southwest University, Chongqing, 400716, China
| | - Yubo Ma
- College of Horticulture and Landscape Architecture, Southwest University, Chongqing, 400716, China
| | - Lu Kou
- College of Horticulture and Landscape Architecture, Southwest University, Chongqing, 400716, China
| | - Juanjuan Wei
- College of Horticulture and Landscape Architecture, Southwest University, Chongqing, 400716, China.,Key Laboratory of Horticulture Science for Southern Mountainous Regions from Ministry of Education, No.2 Tiansheng Road, Beibei District, Chongqing, 400716, China
| | - Weixing Wang
- College of Horticulture and Landscape Architecture, Southwest University, Chongqing, 400716, China. .,Key Laboratory of Horticulture Science for Southern Mountainous Regions from Ministry of Education, No.2 Tiansheng Road, Beibei District, Chongqing, 400716, China.
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Biophenolic Profile Modulations in Olive Tissues as Affected by Manganese Nutrition. PLANTS 2021; 10:plants10081724. [PMID: 34451769 PMCID: PMC8402200 DOI: 10.3390/plants10081724] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 08/10/2021] [Accepted: 08/16/2021] [Indexed: 11/23/2022]
Abstract
Manganese (Mn) is an essential element that intervenes in several plant metabolic processes. The olive tree, and its fruits and leaves, are known as a source of nutraceuticals since they are rich in biophenols. However, there is still a serious lack of data about biophenolic distribution in olive stems and roots under Mn fertilisation. In this context, our study aimed to examine the effects of Mn fertilisation on the biophenolic profile in the leaves, stems, and roots of the ‘Istarska bjelica’ olive cultivar. The experiment was set up in a greenhouse, during a period of five months, as a random block design consisting of three treatments with varying Mn concentrations in full-strength Hoagland’s nutrient solution (0.2 µM Mn, 12 µM Mn, and 24 µM Mn). The obtained results indicate that the amount of Mn in the examined olive plant tissues was significantly higher under 12 µM Mn and 24 µM Mn treatments compared to that of the 0.2 µM Mn treatment. While the concentration of biophenols varied in roots depending on the compound in question, a strong positive impact of the increased Mn concentration in nutrient solution (12 µM Mn and 24 µM Mn) on the concentrations of the main biophenolic compounds was observed in stems. The concentration of oleuropein in leaves almost doubled at 24 µM Mn, with the highest Mn concentration, as compared to the 0.2 µM Mn treatment. The obtained results led to the conclusion that the supply of Mn could enhance the concentration of some biologically active compounds in olives grown hydroponically, implying a critical need for further investigation of Mn fertilisation practices in the conventional olive farming system.
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Lyko P, Wicke S. Genomic reconfiguration in parasitic plants involves considerable gene losses alongside global genome size inflation and gene births. PLANT PHYSIOLOGY 2021; 186:1412-1423. [PMID: 33909907 PMCID: PMC8260112 DOI: 10.1093/plphys/kiab192] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 04/13/2021] [Indexed: 05/02/2023]
Abstract
Parasitic plant genomes and transcriptomes reveal numerous genetic innovations, the functional-evolutionary relevance and roles of which open unprecedented research avenues.
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Affiliation(s)
- Peter Lyko
- Institute for Biology, Humboldt-University of Berlin, Germany
| | - Susann Wicke
- Institute for Biology, Humboldt-University of Berlin, Germany
- Author for communication:
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Guo X, Zhang G, Fan L, Liu C, Ji Y. Highly degenerate plastomes in two hemiparasitic dwarf mistletoes: Arceuthobium chinense and A. pini (Viscaceae). PLANTA 2021; 253:125. [PMID: 34028602 DOI: 10.1007/s00425-021-03643-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 05/19/2021] [Indexed: 06/12/2023]
Abstract
The leafless and endophytic habitat may significantly relax the selection pressure on photosynthesis, and plastid transcription and translation, causing the loss/pseudogenization of several essential plastid-encoding genes in dwarf mistletoes. Dwarf mistletoes (Arceuthobium spp., Viscaceae) are the most destructive plant parasites to numerous conifer species worldwide. In this study, the plastid genomes (plastomes) of Arceuthobium chinense Lecomte and A. pini Hawksworth and Wiens were sequenced and characterized. Although dwarf mistletoes are hemiparasites capable of photosynthesis, their plastomes were highly degenerated, as indicated by the smallest plastome size, the lowest GC content, and relatively very few intact genes among the Santalales hemiparasites. Unexpectedly, several essential housekeeping genes (rpoA, rpoB, rpoC1, and rpoC2) and some core photosynthetic genes (psbZ and petL), as well as the rpl33 gene, that is indispensable for plants under stress conditions, were deleted or pseudogenized in the Arceuthobium plastomes. Our data suggest that the leafless and endophytic habit, which heavily relies on the coniferous hosts for nutrients and carbon requirement, may largely relax the selection pressure on photosynthesis, as well as plastid transcription and translation, thus resulting in the loss/pseudogenization of such essential plastid-encoding genes in dwarf mistletoes. Therefore, the higher level of plastome degradation in Arceuthobium species than other Santalales hemiparasites is likely correlated with the evolution of leafless and endophytic habit. A higher degree of plastome degradation in Arceuthobium. These findings provide new insights into the plastome degeneration associated with parasitism in Santalales and deepen our understanding of the biology of dwarf mistletoes.
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Affiliation(s)
- Xiaorong Guo
- Institute of Ecology and Geobotany, Yunnan University, Kunming, Yunnan, China
- School of Ecology and Environmental Science, Yunnan University, Kunming, Yunnan, China
| | - Guangfei Zhang
- Institute of Ecology and Geobotany, Yunnan University, Kunming, Yunnan, China
- School of Ecology and Environmental Science, Yunnan University, Kunming, Yunnan, China
| | - Linyuan Fan
- Yunnan General Administration of Forestry Seeds and Seedlings, Kunming, Yunnan, China
| | - Changkun Liu
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Yunheng Ji
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China.
- Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Population, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China.
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7
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Garcia LE, Edera AA, Palmer JD, Sato H, Sanchez-Puerta MV. Horizontal gene transfers dominate the functional mitochondrial gene space of a holoparasitic plant. THE NEW PHYTOLOGIST 2021; 229:1701-1714. [PMID: 32929737 DOI: 10.1111/nph.16926] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 09/02/2020] [Indexed: 06/11/2023]
Abstract
Although horizontal gene transfer (HGT) is common in angiosperm mitochondrial DNAs (mtDNAs), few cases of functional foreign genes have been identified. The one outstanding candidate for large-scale functional HGT is the holoparasite Lophophytum mirabile, whose mtDNA has lost most native genes but contains intact foreign homologs acquired from legume host plants. To investigate the extent to which this situation results from functional replacement of native by foreign genes, functional mitochondrial gene transfer to the nucleus, and/or loss of mitochondrial biochemical function in the context of extreme parasitism, we examined the Lophophytum mitochondrial and nuclear transcriptomes by deep paired-end RNA sequencing. Most foreign mitochondrial genes in Lophophytum are highly transcribed, accurately spliced, and efficiently RNA edited. By contrast, we found no evidence for functional gene transfer to the nucleus or loss of mitochondrial functions in Lophophytum. Many functional replacements occurred via the physical replacement of native genes by foreign genes. Some of these events probably occurred as the final act of HGT itself. Lophophytum mtDNA has experienced an unprecedented level of functional replacement of native genes by foreign copies. This raises important questions concerning population-genetic and molecular regimes that underlie such a high level of foreign gene takeover.
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Affiliation(s)
- Laura E Garcia
- IBAM, Universidad Nacional de Cuyo, CONICET, Facultad de Ciencias Agrarias, Almirante Brown 500, Chacras de Coria, M5528AHB, Argentina
- Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Padre Jorge Contreras 1300, Mendoza, M5502JMA, Argentina
| | - Alejandro A Edera
- IBAM, Universidad Nacional de Cuyo, CONICET, Facultad de Ciencias Agrarias, Almirante Brown 500, Chacras de Coria, M5528AHB, Argentina
| | - Jeffrey D Palmer
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA
| | - Hector Sato
- Facultad de Ciencias Agrarias (UNJu), Cátedra de Botánica General-Herbario JUA, Alberdi 47, Jujuy, CP 4600, Argentina
| | - M Virginia Sanchez-Puerta
- IBAM, Universidad Nacional de Cuyo, CONICET, Facultad de Ciencias Agrarias, Almirante Brown 500, Chacras de Coria, M5528AHB, Argentina
- Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Padre Jorge Contreras 1300, Mendoza, M5502JMA, Argentina
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8
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Yu Y, Li HT, Wu YH, Li DZ. Correlation Analysis Reveals an Important Role of GC Content in Accumulation of Deletion Mutations in the Coding Region of Angiosperm Plastomes. J Mol Evol 2021; 89:73-80. [PMID: 33433638 DOI: 10.1007/s00239-020-09987-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 12/21/2020] [Indexed: 10/22/2022]
Abstract
Variation in GC content is assumed to correlate with various processes, including mutation biases, recombination, and environmental parameters. To date, most genomic studies exploring the evolution of GC content have focused on nuclear genomes, but relatively few have concentrated on organelle genomes. We explored the mechanisms maintaining the GC content in angiosperm plastomes, with a particular focus on the hypothesis of phylogenetic dependence and the correlation with deletion mutations. We measured three genetic traits, namely, GC content, A/T tracts, and G/C tracts, in the coding region of plastid genomes for 1382 angiosperm species representing 350 families and 64 orders, and tested the phylogenetic signal. Then, we performed correlation analyses and revealed the variation in evolutionary rate of selected traits using RRphylo. The plastid GC content in the coding region varied from 28.10% to 43.20% across angiosperms, with a few non-photosynthetic species showing highly reduced values, highlighting the significance of functional constraints. We found strong phylogenetic signal in A/T tracts, but weak ones in GC content and G/C tracts, indicating adaptive potential. GC content was positively and negatively correlated with G/C and A/T tracts, respectively, suggesting a trade-off between these two deletion events. GC content evolved at various rates across the phylogeny, with significant increases in monocots and Lamiids, and a decrease in Fabids, implying the effects of some other factors. We hypothesize that variation in plastid GC content might be a mixed strategy of species to optimize fitness in fluctuating climates, partly through influencing the trade-off between AT → GC and GC → AT mutations.
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Affiliation(s)
- Ying Yu
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 311121, China
| | - Hong-Tao Li
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
| | - Yu-Huan Wu
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 311121, China.
| | - De-Zhu Li
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China.
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Guo X, Liu C, Wang H, Zhang G, Yan H, Jin L, Su W, Ji Y. The complete plastomes of two flowering epiparasites (Phacellaria glomerata and P. compressa): Gene content, organization, and plastome degradation. Genomics 2020; 113:447-455. [PMID: 33370586 DOI: 10.1016/j.ygeno.2020.12.031] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 03/10/2020] [Accepted: 12/22/2020] [Indexed: 11/28/2022]
Abstract
A plant parasite obligately parasitizing another plant parasite is referred to as epiparasite, which is extremely rare in angiosperms, and their complete plastome sequences have not been characterized to date. In this study, the complete plastomes of two flowering epiparasites: Phacellaria compressa and P. glomerata (Amphorogynaceae, Santalales) were sequenced. The plastomes of both species are of similar size, structure, gene content, and arrangement of genes to other hemiparasites in Santalales. Their plastomes were characterized by the functional loss of plastid-encoded NAD(P)H-dehydrogenase and infA genes, which strongly coincides with the general pattern of plastome degradation observed in Santalales hemiparasites. Our study demonstrates that the relatively higher level of nutritional reliance on the host plants and the reduced vegetative bodies of P. compressa and P. glomerata do not appear to cause any unique plastome degradation compared with their closely related hemiparasites.
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Affiliation(s)
- Xiaorong Guo
- Institute of Ecology and Geobotany, Yunnan University, Kunming, Yunnan, China
| | - Changkun Liu
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Hengchang Wang
- CAS Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China
| | - Guangfei Zhang
- Institute of Ecology and Geobotany, Yunnan University, Kunming, Yunnan, China
| | - Hanjing Yan
- School of Traditional Chinese Medicine, Guangdong Pharmaceutical University, Guangzhou, Guangdong, China
| | - Lei Jin
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China; School of Traditional Chinese Medicine, Guangdong Pharmaceutical University, Guangzhou, Guangdong, China
| | - Wenhua Su
- Institute of Ecology and Geobotany, Yunnan University, Kunming, Yunnan, China
| | - Yunheng Ji
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China; Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Population, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China.
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Hu L, Wang J, Yang C, Islam F, Bouwmeester HJ, Muños S, Zhou W. The Effect of Virulence and Resistance Mechanisms on the Interactions between Parasitic Plants and Their Hosts. Int J Mol Sci 2020; 21:E9013. [PMID: 33260931 PMCID: PMC7730841 DOI: 10.3390/ijms21239013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/26/2020] [Accepted: 10/31/2020] [Indexed: 01/06/2023] Open
Abstract
Parasitic plants have a unique heterotrophic lifestyle based on the extraction of water and nutrients from host plants. Some parasitic plant species, particularly those of the family Orobanchaceae, attack crops and cause substantial yield losses. The breeding of resistant crop varieties is an inexpensive way to control parasitic weeds, but often does not provide a long-lasting solution because the parasites rapidly evolve to overcome resistance. Understanding mechanisms underlying naturally occurring parasitic plant resistance is of great interest and could help to develop methods to control parasitic plants. In this review, we describe the virulence mechanisms of parasitic plants and resistance mechanisms in their hosts, focusing on obligate root parasites of the genera Orobanche and Striga. We noticed that the resistance (R) genes in the host genome often encode proteins with nucleotide-binding and leucine-rich repeat domains (NLR proteins), hence we proposed a mechanism by which host plants use NLR proteins to activate downstream resistance gene expression. We speculated how parasitic plants and their hosts co-evolved and discussed what drives the evolution of virulence effectors in parasitic plants by considering concepts from similar studies of plant-microbe interaction. Most previous studies have focused on the host rather than the parasite, so we also provided an updated summary of genomic resources for parasitic plants and parasitic genes for further research to test our hypotheses. Finally, we discussed new approaches such as CRISPR/Cas9-mediated genome editing and RNAi silencing that can provide deeper insight into the intriguing life cycle of parasitic plants and could potentially contribute to the development of novel strategies for controlling parasitic weeds, thereby enhancing crop productivity and food security globally.
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Affiliation(s)
- Luyang Hu
- Institute of Crop Science and Zhejiang Key Lab of Crop Germplasm, Zhejiang University, Hangzhou 310058, China; (L.H.); (J.W.); (F.I.)
| | - Jiansu Wang
- Institute of Crop Science and Zhejiang Key Lab of Crop Germplasm, Zhejiang University, Hangzhou 310058, China; (L.H.); (J.W.); (F.I.)
| | - Chong Yang
- Bioengineering Research Laboratory, Institute of Bioengineering, Guangdong Academy of Sciences, Guangzhou 510316, China;
| | - Faisal Islam
- Institute of Crop Science and Zhejiang Key Lab of Crop Germplasm, Zhejiang University, Hangzhou 310058, China; (L.H.); (J.W.); (F.I.)
| | - Harro J. Bouwmeester
- Swammerdam Institute for Life Sciences, University of Amsterdam, 1000 BE Amsterdam, The Netherlands;
| | - Stéphane Muños
- LIPM, Université de Toulouse, INRAE, CNRS, 31326 Castanet-Tolosan, France;
| | - Weijun Zhou
- Institute of Crop Science and Zhejiang Key Lab of Crop Germplasm, Zhejiang University, Hangzhou 310058, China; (L.H.); (J.W.); (F.I.)
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Preuss M, Verbruggen H, Zuccarello GC. The Organelle Genomes in the Photosynthetic Red Algal Parasite Pterocladiophila hemisphaerica (Florideophyceae, Rhodophyta) Have Elevated Substitution Rates and Extreme Gene Loss in the Plastid Genome. JOURNAL OF PHYCOLOGY 2020; 56:1006-1018. [PMID: 32215918 DOI: 10.1111/jpy.12996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Accepted: 03/06/2020] [Indexed: 06/10/2023]
Abstract
Comparative organelle genome studies of parasites can highlight genetic changes that occur during the transition from a free-living to a parasitic state. Our study focuses on a poorly studied group of red algal parasites, which are often closely related to their red algal hosts and from which they presumably evolved. Most of these parasites are pigmented and some show photosynthetic capacity. Here, we assembled and annotated the complete organelle genomes of the photosynthetic red algal parasite, Pterocladiophila hemisphaerica. The plastid genome is the smallest known red algal plastid genome at 68,701 bp. The plastid genome has many genes missing, including all photosynthesis-related genes. In contrast, the mitochondrial genome is similar in architecture to that of other free-living red algae. Both organelle genomes show elevated mutation rates and significant changes in patterns of selection, measured as dN/dS ratios. This caused phylogenetic analyses, even of multiple aligned proteins, to be unresolved or give contradictory relationships. Full plastid datasets interfered by selected best gene evolution models showed the supported relationship of P. hemisphaerica within the Ceramiales, but the parasite was grouped with support as sister to the Gracilariales when interfered under the GHOST model. Nuclear rDNA showed a supported grouping of the parasite within a clade containing several red algal orders including the Gelidiales. This photosynthetic parasite, which is unable to photosynthesize with its own plastid due to the total loss of all photosynthesis genes, raises intriguing questions on parasite-host organelle genome capabilities and interactions.
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Affiliation(s)
- Maren Preuss
- School of Biological Sciences, Victoria University of Wellington, PO Box 600, Wellington, 6140, New Zealand
| | - Heroen Verbruggen
- School of BioSciences, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Giuseppe C Zuccarello
- School of Biological Sciences, Victoria University of Wellington, PO Box 600, Wellington, 6140, New Zealand
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12
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Guo X, Liu C, Zhang G, Su W, Landis JB, Zhang X, Wang H, Ji Y. The Complete Plastomes of Five Hemiparasitic Plants ( Osyris wightiana, Pyrularia edulis, Santalum album, Viscum liquidambaricolum, and V. ovalifolium): Comparative and Evolutionary Analyses Within Santalales. Front Genet 2020; 11:597. [PMID: 32612639 PMCID: PMC7308561 DOI: 10.3389/fgene.2020.00597] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 05/18/2020] [Indexed: 11/27/2022] Open
Abstract
Most species of Santalales (the sandalwood order) are hemiparasites, including both facultative and obligate hemiparasites. Despite its rich diversity, only a small fraction of the species in the sandalwood order have sequenced plastomes. The evolution of parasitism-associated plastome reduction in Santalales remains under-studied. Here, we report the complete plastomes of three facultative hemiparasites (Pyrularia edulis, Cervantesiaceae; Osyris wightiana, and Santalum album, Santalaceae), and two obligate hemiparasites (Viscum liquidambaricolum and Viscum ovalifolium, Viscaceae). Coupled with publicly available data, we investigated the dynamics of plastome degradation in Santalales hemiparasites. Our results indicate that these hemiparasites can be characterized by various degrees of plastome downsizing, structural rearrangement, and gene loss. The loss or pseudogenization of ndh genes was commonly observed in Santalales hemiparasites, which may be correlated to the lifestyle shift from photoautotroph to hemiparasitism. However, the obligate hemiparasites did not exhibit a consistently higher level of gene loss or pseudogenization compared to facultative hemiparasites, which suggests that the degree of plastome reduction is not correlated with the trophic level facultative or obligate hemiparasitism. Instead, closely related taxa tend to possess highly similar plastome size, structure, and gene content. This implies the parasitism-associated plastome degradation in Santalales may evolve in a lineage-specific manner.
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Affiliation(s)
- Xiaorong Guo
- Institute of Ecology and Geobotany, Yunnan University, Kunming, China
| | - Changkun Liu
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Guangfei Zhang
- Institute of Ecology and Geobotany, Yunnan University, Kunming, China
| | - Wenhua Su
- Institute of Ecology and Geobotany, Yunnan University, Kunming, China
| | - Jacob B. Landis
- Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA, United States
| | - Xu Zhang
- CAS Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China
| | - Hengchang Wang
- CAS Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China
| | - Yunheng Ji
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
- Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Population, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
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13
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Chen J, Yu R, Dai J, Liu Y, Zhou R. The loss of photosynthesis pathway and genomic locations of the lost plastid genes in a holoparasitic plant Aeginetia indica. BMC PLANT BIOLOGY 2020; 20:199. [PMID: 32384868 PMCID: PMC7206726 DOI: 10.1186/s12870-020-02415-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Accepted: 04/29/2020] [Indexed: 05/18/2023]
Abstract
BACKGROUND With three origins of holoparasitism, Orobanchaceae provides an ideal system to study the evolution of holoparasitic lifestyle in plants. The evolution of holoparasitism can be revealed by plastid genome degradation and coordinated changes in the nuclear genome, since holoparasitic plants lost the capability of photosynthesis. Among the three clades with holoparasitic plants in Orobanchaceae, only Clade VI has no available plastid genome sequences for holoparasitic plants. In this study, we sequenced the plastome and transcriptome of Aeginetia indica, a holoparasitic plant in Clade VI of Orobanchaceae, to study its plastome evolution and the corresponding changes in the nuclear genome as a response of the loss of photosynthetic function. RESULTS The plastome of A. indica is reduced to 86,212 bp in size, and almost all photosynthesis-related genes were lost. Massive fragments of the lost plastid genes were transferred into the mitochondrial and/or nuclear genomes. These fragments could not be detected in its transcriptomes, suggesting that they were non-functional. Most protein coding genes in the plastome showed the signal of relaxation of purifying selection. Plastome and transcriptome analyses indicated that the photosynthesis pathway is completely lost, and that the porphyrin and chlorophyll metabolism pathway is partially retained, although chlorophyll synthesis is not possible. CONCLUSIONS Our study suggests the loss of photosynthesis-related functions in A. indica in both the nuclear and plastid genomes. The lost plastid genes are transferred into its nuclear and/or mitochondrial genomes, and exist in very small fragments with no expression and are thus non-functional. The Aeginetia indica plastome also provides a resource for comparative studies on the repeated evolution of holoparasitism in Orobanchaceae.
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Affiliation(s)
- Jingfang Chen
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China
| | - Runxian Yu
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China
| | - Jinhong Dai
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China
| | - Ying Liu
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China
| | - Renchao Zhou
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China.
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14
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Petersen G, Anderson B, Braun HP, Meyer EH, Møller IM. Mitochondria in parasitic plants. Mitochondrion 2020; 52:173-182. [DOI: 10.1016/j.mito.2020.03.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 03/05/2020] [Accepted: 03/23/2020] [Indexed: 02/06/2023]
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15
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Banerjee A. Inter-plant communication via parasitic bridging. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:749-750. [PMID: 31971243 DOI: 10.1093/jxb/erz507] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
This article comments on:
Li S, Zhang J, Liu H, Liu N, Shen G, Zhuang H, Wu J. 2020. Dodder-transmitted mobile signals prime host plants for enhanced salt tolerance. Journal of Experimental Botany 71, 1171–1184.
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Affiliation(s)
- Arjan Banerjee
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, Canada
- Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
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16
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Liu X, Fu W, Tang Y, Zhang W, Song Z, Li L, Yang J, Ma H, Yang J, Zhou C, Davis CC, Wang Y. Diverse trajectories of plastome degradation in holoparasitic Cistanche and genomic location of the lost plastid genes. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:877-892. [PMID: 31639183 DOI: 10.1093/jxb/erz456] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 10/04/2019] [Indexed: 06/10/2023]
Abstract
The plastid genomes (plastomes) of non-photosynthetic plants generally undergo gene loss and pseudogenization. Despite massive plastomes reported in different parasitism types of the broomrape family (Orobanchaceae), more plastomes representing different degradation patterns in a single genus are expected to be explored. Here, we sequence and assemble the complete plastomes of three holoparasitic Cistanche species (C. salsa, C. mongolica, and C. sinensis) and compare them with the available plastomes of Orobanchaceae. We identified that the diverse degradation trajectories under purifying selection existed among three Cistanche clades, showing obvious size differences in the entire plastome, long single copy region, and non-coding region, and different patterns of the retention/loss of functional genes. With few exceptions of putatively functional genes, massive plastid fragments, which have been lost and transferred into the mitochondrial or nuclear genomes, are non-functional. In contrast to the equivalents of the Orobanche species, some plastid-derived genes with diverse genomic locations are found in Cistanche. The early and initially diverged clades in different genera such as Cistanche and Aphyllon possess obvious patterns of plastome degradation, suggesting that such key lineages should be considered prior to comparative analysis of plastome evolution, especially in the same genus.
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Affiliation(s)
- Xiaoqing Liu
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, School of Life Sciences, Fudan University, Shanghai, China
| | - Weirui Fu
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, School of Life Sciences, Fudan University, Shanghai, China
| | - Yiwei Tang
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, School of Life Sciences, Fudan University, Shanghai, China
| | - Wenju Zhang
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, School of Life Sciences, Fudan University, Shanghai, China
| | - Zhiping Song
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, School of Life Sciences, Fudan University, Shanghai, China
| | - Linfeng Li
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, School of Life Sciences, Fudan University, Shanghai, China
| | - Ji Yang
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, School of Life Sciences, Fudan University, Shanghai, China
| | - Hong Ma
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Institute of Plant Biology, Center for Evolutionary Biology, Fudan University, Shanghai, China
- Department of Biology, Institute of Molecular Evolutionary Genetics, and the Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA
| | - Jianhua Yang
- College of Pharmacy, The First Affiliated Hospital, Xinjiang Medical University, Urumqi, China
| | - Chan Zhou
- Department of Population and Quantitative Health Sciences, Massachusetts General Hospital, 55 Lake Ave, North Worcester, MA, USA
| | - Charles C Davis
- Department of Organismic and Evolutionary Biology, Harvard University Herbaria, 22 Divinity Avenue, Cambridge, MA, USA
| | - Yuguo Wang
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, School of Life Sciences, Fudan University, Shanghai, China
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Gruzdev EV, Kadnikov VV, Beletsky AV, Mardanov AV, Ravin NV. Extensive plastome reduction and loss of photosynthesis genes in Diphelypaea coccinea, a holoparasitic plant of the family Orobanchaceae. PeerJ 2019; 7:e7830. [PMID: 31592357 PMCID: PMC6778433 DOI: 10.7717/peerj.7830] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 09/04/2019] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Parasitic plants have the ability to obtain nutrients from their hosts and are less dependent on their own photosynthesis or completely lose this capacity. The reduction in plastid genome size and gene content in parasitic plants predominantly results from loss of photosynthetic genes. Plants from the family Orobanchaceae are used as models for studying plastid genome evolution in the transition from an autotrophic to parasitic lifestyle. Diphelypaea is a poorly studied genus of the Orobanchaceae, comprising two species of non-photosynthetic root holoparasites. In this study, we sequenced the plastid genome of Diphelypaea coccinea and compared it with other Orobanchaceae, to elucidate patterns of plastid genome evolution. In addition, we used plastid genome data to define the phylogenetic position of Diphelypaea spp. METHODS The complete nucleotide sequence of the plastid genome of D. coccinea was obtained from total plant DNA, using pyrosequencing technology. RESULTS The D. coccinea plastome is only 66,616 bp in length, and is highly rearranged; however, it retains a quadripartite structure. It contains only four rRNA genes, 25 tRNA genes and 25 protein-coding genes, being one of the most highly reduced plastomes among the parasitic Orobanchaceae. All genes related to photosynthesis, including the ATP synthase genes, had been lost, whereas most housekeeping genes remain intact. The plastome contains two divergent, but probably intact clpP genes. Intron loss had occurred in some protein-coding and tRNA genes. Phylogenetic analysis yielded a fully resolved tree for the Orobanchaceae, with Diphelypaea being a sister group to Orobanche sect. Orobanche.
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Affiliation(s)
- Eugeny V. Gruzdev
- Institute of Bioengineering, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia
- Moscow State University, Moscow, Russia
| | - Vitaly V. Kadnikov
- Institute of Bioengineering, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia
| | - Alexey V. Beletsky
- Institute of Bioengineering, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia
| | - Andrey V. Mardanov
- Institute of Bioengineering, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia
| | - Nikolai V. Ravin
- Institute of Bioengineering, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia
- Moscow State University, Moscow, Russia
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18
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Banerjee A, Stefanović S. Correction to: Caught in action: fine-scale plastome evolution in the parasitic plants of Cuscuta section Ceratophorae (Convolvulaceae). PLANT MOLECULAR BIOLOGY 2019; 101:341. [PMID: 31552585 DOI: 10.1007/s11103-019-00912-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Regrettably, an in-text citation wasn't listed in the reference section of the above mentioned publication. The citation reads Schneider et al. (2018) and the correct reference is published here.
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Affiliation(s)
- Arjan Banerjee
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, L5L 1C6, Canada.
- Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, M5S 2Z9, Canada.
| | - Saša Stefanović
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, L5L 1C6, Canada
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19
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Barrett CF, Sinn BT, Kennedy AH. Unprecedented Parallel Photosynthetic Losses in a Heterotrophic Orchid Genus. Mol Biol Evol 2019; 36:1884-1901. [PMID: 31058965 PMCID: PMC6736286 DOI: 10.1093/molbev/msz111] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Heterotrophic plants are evolutionary experiments in genomic, morphological, and physiological change. Yet, genomic sampling gaps exist among independently derived heterotrophic lineages, leaving unanswered questions about the process of genome modification. Here, we have sequenced complete plastid genomes for all species of the leafless orchid genus Hexalectris, including multiple individuals for most, and leafy relatives Basiphyllaea and Bletia. Our objectives are to determine the number of independent losses of photosynthesis and to test hypotheses on the process of genome degradation as a result of relaxed selection. We demonstrate four to five independent losses of photosynthesis in Hexalectris based on degradation of the photosynthetic apparatus, with all but two species displaying evidence of losses, and variation in gene loss extending below the species level. Degradation in the atp complex is advanced in Hexalectris warnockii, whereas only minimal degradation (i.e., physical loss) has occurred among some "housekeeping" genes. We find genomic rearrangements, shifts in Inverted Repeat boundaries including complete loss in one accession of H. arizonica, and correlations among substitutional and genomic attributes. Our unprecedented finding of multiple, independent transitions to a fully mycoheterotrophic lifestyle in a single genus reveals that the number of such transitions among land plants is likely underestimated. This study underscores the importance of dense taxon sampling, which is highly informative for advancing models of genome evolution in heterotrophs. Mycoheterotrophs such as Hexalectris provide forward-genetic opportunities to study the consequences of radical genome evolution beyond what is possible with mutational studies in model organisms alone.
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Affiliation(s)
- Craig F Barrett
- Department of Biology, West Virginia University, Morgantown, WV
| | - Brandon T Sinn
- Department of Biology, West Virginia University, Morgantown, WV
| | - Aaron H Kennedy
- Mycology and Nematology Genetic Diversity and Biology Laboratory, USDA-APHIS, Beltsville, MD
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20
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Schneider AC, Braukmann T, Banerjee A, Stefanovic S. Convergent Plastome Evolution and Gene Loss in Holoparasitic Lennoaceae. Genome Biol Evol 2018; 10:2663-2670. [PMID: 30169817 PMCID: PMC6178340 DOI: 10.1093/gbe/evy190] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/28/2018] [Indexed: 11/15/2022] Open
Abstract
The Lennoaceae, a small monophyletic plant family of root parasites endemic to the Americas, are one of the last remaining independently evolved lineages of parasitic angiosperms lacking a published plastome. In this study, we present the assembled and annotated plastomes of two species spanning the crown node of Lennoaceae, Lennoa madreporoides and Pholisma arenarium, as well as their close autotrophic relative from the sister family Ehretiaceae, Tiquilia plicata. We find that the plastomes of L. madreporoides and P. arenarium are similar in size and gene content, and substantially reduced compared to T. plicata, consistent with trends seen in other holoparasitic lineages. In particular, most plastid genes involved in photosynthesis function have been lost, whereas housekeeping genes (ribosomal protein-coding genes, rRNAs, and tRNAs) are retained. One notable exception is the persistence of a rbcL open reading frame in P. arenarium but not L. madreporoides suggesting a nonphotosynthetic function for this gene. Of the retained coding genes, dN/dS ratios indicate that some remain under purifying selection, whereas others show relaxed selection. Overall, this study supports the mounting evidence for convergent plastome evolution in flowering plants following the shift to heterotrophy.
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Affiliation(s)
- Adam C Schneider
- Department of Biology, University of Toronto Mississauga, Ontario, Canada.,Department of Ecology and Evolutionary Biology, University of Toronto, Ontario, Canada.,Department of Biology, Hendrix College, Conway, AR
| | - Thomas Braukmann
- Centre for Biodiversity Genomics, University of Guelph, Ontario, Canada
| | - Arjan Banerjee
- Department of Biology, University of Toronto Mississauga, Ontario, Canada.,Department of Ecology and Evolutionary Biology, University of Toronto, Ontario, Canada
| | - Saša Stefanovic
- Department of Biology, University of Toronto Mississauga, Ontario, Canada
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