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Torres DE, Kramer HM, Tracanna V, Fiorin GL, Cook DE, Seidl MF, Thomma BPHJ. Implications of the three-dimensional chromatin organization for genome evolution in a fungal plant pathogen. Nat Commun 2024; 15:1701. [PMID: 38402218 PMCID: PMC10894299 DOI: 10.1038/s41467-024-45884-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 02/05/2024] [Indexed: 02/26/2024] Open
Abstract
The spatial organization of eukaryotic genomes is linked to their biological functions, although it is not clear how this impacts the overall evolution of a genome. Here, we uncover the three-dimensional (3D) genome organization of the phytopathogen Verticillium dahliae, known to possess distinct genomic regions, designated adaptive genomic regions (AGRs), enriched in transposable elements and genes that mediate host infection. Short-range DNA interactions form clear topologically associating domains (TADs) with gene-rich boundaries that show reduced levels of gene expression and reduced genomic variation. Intriguingly, TADs are less clearly insulated in AGRs than in the core genome. At a global scale, the genome contains bipartite long-range interactions, particularly enriched for AGRs and more generally containing segmental duplications. Notably, the patterns observed for V. dahliae are also present in other Verticillium species. Thus, our analysis links 3D genome organization to evolutionary features conserved throughout the Verticillium genus.
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Affiliation(s)
- David E Torres
- Laboratory of Phytopathology, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands
- Theoretical Biology & Bioinformatics Group, Department of Biology, Utrecht University, Utrecht, The Netherlands
| | - H Martin Kramer
- Laboratory of Phytopathology, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands
| | - Vittorio Tracanna
- University of Cologne, Institute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS), Cologne, Germany
| | - Gabriel L Fiorin
- Laboratory of Phytopathology, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands
| | - David E Cook
- Laboratory of Phytopathology, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands
- Department of Plant Pathology, Kansas State University, 1712 Claflin Road, Manhattan, KS, USA
| | - Michael F Seidl
- Laboratory of Phytopathology, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands.
- Theoretical Biology & Bioinformatics Group, Department of Biology, Utrecht University, Utrecht, The Netherlands.
| | - Bart P H J Thomma
- Laboratory of Phytopathology, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands.
- University of Cologne, Institute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS), Cologne, Germany.
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Chavarro-Carrero EA, Snelders NC, Torres DE, Kraege A, López-Moral A, Petti GC, Punt W, Wieneke J, García-Velasco R, López-Herrera CJ, Seidl MF, Thomma BPHJ. The soil-borne white root rot pathogen Rosellinia necatrix expresses antimicrobial proteins during host colonization. PLoS Pathog 2024; 20:e1011866. [PMID: 38236788 PMCID: PMC10796067 DOI: 10.1371/journal.ppat.1011866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 11/27/2023] [Indexed: 01/22/2024] Open
Abstract
Rosellinia necatrix is a prevalent soil-borne plant-pathogenic fungus that is the causal agent of white root rot disease in a broad range of host plants. The limited availability of genomic resources for R. necatrix has complicated a thorough understanding of its infection biology. Here, we sequenced nine R. necatrix strains with Oxford Nanopore sequencing technology, and with DNA proximity ligation we generated a gapless assembly of one of the genomes into ten chromosomes. Whereas many filamentous pathogens display a so-called two-speed genome with more dynamic and more conserved compartments, the R. necatrix genome does not display such genome compartmentalization. It has recently been proposed that fungal plant pathogens may employ effectors with antimicrobial activity to manipulate the host microbiota to promote infection. In the predicted secretome of R. necatrix, 26 putative antimicrobial effector proteins were identified, nine of which are expressed during plant colonization. Two of the candidates were tested, both of which were found to possess selective antimicrobial activity. Intriguingly, some of the inhibited bacteria are antagonists of R. necatrix growth in vitro and can alleviate R. necatrix infection on cotton plants. Collectively, our data show that R. necatrix encodes antimicrobials that are expressed during host colonization and that may contribute to modulation of host-associated microbiota to stimulate disease development.
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Affiliation(s)
- Edgar A. Chavarro-Carrero
- Laboratory of Phytopathology, Wageningen University & Research, Wageningen, The Netherlands
- Institute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, Germany
| | - Nick C. Snelders
- Institute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, Germany
- Theoretical Biology & Bioinformatics Group, Department of Biology, Utrecht University, Utrecht, The Netherlands
| | - David E. Torres
- Laboratory of Phytopathology, Wageningen University & Research, Wageningen, The Netherlands
- Theoretical Biology & Bioinformatics Group, Department of Biology, Utrecht University, Utrecht, The Netherlands
| | - Anton Kraege
- Institute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, Germany
| | - Ana López-Moral
- Institute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, Germany
| | - Gabriella C. Petti
- Institute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, Germany
| | - Wilko Punt
- Institute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, Germany
| | - Jan Wieneke
- Institute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, Germany
| | - Rómulo García-Velasco
- Laboratory of Phytopathology, Tenancingo University Center, Autonomous University of the State of Mexico, Tenancingo, State of Mexico, Mexico
| | - Carlos J. López-Herrera
- CSIC, Instituto de Agricultura Sostenible, Dept. Protección de Cultivos, C/Alameda del Obispo s/n, Córdoba, Spain
| | - Michael F. Seidl
- Theoretical Biology & Bioinformatics Group, Department of Biology, Utrecht University, Utrecht, The Netherlands
| | - Bart P. H. J. Thomma
- Laboratory of Phytopathology, Wageningen University & Research, Wageningen, The Netherlands
- Institute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, Germany
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Abstract
Comparative genomics has recently provided unprecedented insights into the biology and evolution of the fungal lineage. In the post-genomics era, a major research interest focuses now on detailing the functions of fungal genomes, i.e. how genomic information manifests into complex phenotypes. Emerging evidence across diverse eukaryotes has revealed that the organization of DNA within the nucleus is critically important. Here, we discuss the current knowledge on the fungal genome organization, from the association of chromosomes within the nucleus to topological structures at individual genes and the genetic factors required for this hierarchical organization. Chromosome conformation capture followed by high-throughput sequencing (Hi-C) has elucidated how fungal genomes are globally organized in Rabl configuration, in which centromere or telomere bundles are associated with opposite faces of the nuclear envelope. Further, fungal genomes are regionally organized into Topologically Associated Domain-like (TAD-like) chromatin structures. We discuss how chromatin organization impacts the proper function of DNA-templated processes across the fungal genome. Nevertheless, this view is limited to a few fungal taxa given the paucity of fungal Hi-C experiments. We advocate for exploring genome organization across diverse fungal lineages to ensure the future understanding of the impact of nuclear organization on fungal genome function.
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Affiliation(s)
- David E Torres
- Theoretical Biology & Bioinformatics, Department of Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
- Laboratory of Phytopathology, Wageningen University and Research, Droevendaalsesteeg 4, 6708 PB Wageningen, The Netherlands
| | - Andrew T Reckard
- Department of Chemistry & Biochemistry, University of Colorado Colorado Springs, 234 Centennial Hall, 1420 Austin Bluffs Pkwy, Colorado Springs, CO 80918USA
| | - Andrew D Klocko
- Department of Chemistry & Biochemistry, University of Colorado Colorado Springs, 234 Centennial Hall, 1420 Austin Bluffs Pkwy, Colorado Springs, CO 80918USA
| | - Michael F Seidl
- Theoretical Biology & Bioinformatics, Department of Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
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Snelders NC, Boshoven JC, Song Y, Schmitz N, Fiorin GL, Rovenich H, van den Berg GCM, Torres DE, Petti GC, Prockl Z, Faino L, Seidl MF, Thomma BPHJ. A highly polymorphic effector protein promotes fungal virulence through suppression of plant-associated Actinobacteria. New Phytol 2023; 237:944-958. [PMID: 36300791 DOI: 10.1111/nph.18576] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 10/17/2022] [Indexed: 06/16/2023]
Abstract
Plant pathogens secrete effector proteins to support host colonization through a wide range of molecular mechanisms, while plant immune systems evolved receptors to recognize effectors or their activities to mount immune responses to halt pathogens. Importantly, plants do not act as single organisms, but rather as holobionts that actively shape their microbiota as a determinant of health. The soil-borne fungal pathogen Verticillium dahliae was recently demonstrated to exploit the VdAve1 effector to manipulate the host microbiota to promote vascular wilt disease in the absence of the corresponding immune receptor Ve1. We identify a multiallelic V. dahliae gene displaying c. 65% sequence similarity to VdAve1, named VdAve1-like (VdAve1L), which shows extreme sequence variation, including alleles that encode dysfunctional proteins, indicative of selection pressure to overcome host recognition. We show that the orphan cell surface receptor Ve2, encoded at the Ve locus, does not recognize VdAve1L. Additionally, we demonstrate that the full-length variant VdAve1L2 possesses antimicrobial activity, like VdAve1, yet with a divergent activity spectrum, that is exploited by V. dahliae to mediate tomato colonization through the direct suppression of antagonistic Actinobacteria in the host microbiota. Our findings open up strategies for more targeted biocontrol against microbial plant pathogens.
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Affiliation(s)
- Nick C Snelders
- Institute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, 50674, Cologne, Germany
- Theoretical Biology and Bioinformatics Group, Department of Biology, University of Utrecht, 3584CH, Utrecht, the Netherlands
| | - Jordi C Boshoven
- Laboratory of Phytopathology, Wageningen University and Research, Droevendaalsesteeg 1, 6708PB, Wageningen, the Netherlands
| | - Yin Song
- Laboratory of Phytopathology, Wageningen University and Research, Droevendaalsesteeg 1, 6708PB, Wageningen, the Netherlands
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Agronomy, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Natalie Schmitz
- Institute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, 50674, Cologne, Germany
| | - Gabriel L Fiorin
- Laboratory of Phytopathology, Wageningen University and Research, Droevendaalsesteeg 1, 6708PB, Wageningen, the Netherlands
| | - Hanna Rovenich
- Institute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, 50674, Cologne, Germany
| | - Grardy C M van den Berg
- Laboratory of Phytopathology, Wageningen University and Research, Droevendaalsesteeg 1, 6708PB, Wageningen, the Netherlands
| | - David E Torres
- Theoretical Biology and Bioinformatics Group, Department of Biology, University of Utrecht, 3584CH, Utrecht, the Netherlands
- Laboratory of Phytopathology, Wageningen University and Research, Droevendaalsesteeg 1, 6708PB, Wageningen, the Netherlands
| | - Gabriella C Petti
- Institute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, 50674, Cologne, Germany
| | - Zoe Prockl
- Institute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, 50674, Cologne, Germany
| | - Luigi Faino
- Laboratory of Phytopathology, Wageningen University and Research, Droevendaalsesteeg 1, 6708PB, Wageningen, the Netherlands
- Department of Ambiental Biology, Sapienza University of Rome, 00185, Rome, Italy
| | - Michael F Seidl
- Theoretical Biology and Bioinformatics Group, Department of Biology, University of Utrecht, 3584CH, Utrecht, the Netherlands
| | - Bart P H J Thomma
- Institute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, 50674, Cologne, Germany
- Laboratory of Phytopathology, Wageningen University and Research, Droevendaalsesteeg 1, 6708PB, Wageningen, the Netherlands
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Torres DE, Thomma BPHJ, Seidl MF. Transposable Elements Contribute to Genome Dynamics and Gene Expression Variation in the Fungal Plant Pathogen Verticillium dahliae. Genome Biol Evol 2021; 13:evab135. [PMID: 34100895 PMCID: PMC8290119 DOI: 10.1093/gbe/evab135] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/04/2021] [Indexed: 12/12/2022] Open
Abstract
Transposable elements (TEs) are a major source of genetic and regulatory variation in their host genome and are consequently thought to play important roles in evolution. Many fungal and oomycete plant pathogens have evolved dynamic and TE-rich genomic regions containing genes that are implicated in host colonization and adaptation. TEs embedded in these regions have typically been thought to accelerate the evolution of these genomic compartments, but little is known about their dynamics in strains that harbor them. Here, we used whole-genome sequencing data of 42 strains of the fungal plant pathogen Verticillium dahliae to systematically identify polymorphic TEs that may be implicated in genomic as well as in gene expression variation. We identified 2,523 TE polymorphisms and characterize a subset of 8% of the TEs as polymorphic elements that are evolutionary younger, less methylated, and more highly expressed when compared with the remaining 92% of the total TE complement. As expected, the polyrmorphic TEs are enriched in the adaptive genomic regions. Besides, we observed an association of polymorphic TEs with pathogenicity-related genes that localize nearby and that display high expression levels. Collectively, our analyses demonstrate that TE dynamics in V. dahliae contributes to genomic variation, correlates with expression of pathogenicity-related genes, and potentially impacts the evolution of adaptive genomic regions.
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Affiliation(s)
- David E Torres
- Theoretical Biology and Bioinformatics Group, Department of Biology, Utrecht University, The Netherlands
- Laboratory of Phytopathology, Wageningen University and Research, The Netherlands
| | - Bart P H J Thomma
- Laboratory of Phytopathology, Wageningen University and Research, The Netherlands
- Cluster of Excellence on Plant Sciences (CEPLAS), Institute for Plant Sciences, University of Cologne, Germany
| | - Michael F Seidl
- Theoretical Biology and Bioinformatics Group, Department of Biology, Utrecht University, The Netherlands
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Chavarro‐Carrero EA, Vermeulen JP, E. Torres D, Usami T, Schouten HJ, Bai Y, Seidl MF, Thomma BPHJ. Comparative genomics reveals the in planta-secreted Verticillium dahliae Av2 effector protein recognized in tomato plants that carry the V2 resistance locus. Environ Microbiol 2021; 23:1941-1958. [PMID: 33078534 PMCID: PMC8246953 DOI: 10.1111/1462-2920.15288] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 10/16/2020] [Accepted: 10/18/2020] [Indexed: 12/12/2022]
Abstract
Plant pathogens secrete effector molecules during host invasion to promote colonization. However, some of these effectors become recognized by host receptors to mount a defence response and establish immunity. Recently, a novel resistance was identified in wild tomato, mediated by the single dominant V2 locus, to control strains of the soil-borne vascular wilt fungus Verticillium dahliae that belong to race 2. With comparative genomics of race 2 strains and resistance-breaking race 3 strains, we identified the avirulence effector that activates V2 resistance, termed Av2. We identified 277 kb of race 2-specific sequence comprising only two genes encoding predicted secreted proteins that are expressed during tomato colonization. Subsequent functional analysis based on genetic complementation into race 3 isolates and targeted deletion from the race 1 isolate JR2 and race 2 isolate TO22 confirmed that one of the two candidates encodes the avirulence effector Av2 that is recognized in V2 tomato plants. Two Av2 allelic variants were identified that encode Av2 variants that differ by a single acid. Thus far, a role in virulence could not be demonstrated for either of the two variants.
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Affiliation(s)
| | - Jasper P. Vermeulen
- Laboratory of PhytopathologyWageningen University and ResearchWageningen6708 PBThe Netherlands
- Laboratory of Plant BreedingWageningen University and ResearchWageningen6708 PBThe Netherlands
| | - David E. Torres
- Laboratory of PhytopathologyWageningen University and ResearchWageningen6708 PBThe Netherlands
- Theoretical Biology and Bioinformatics Group, Department of BiologyUtrecht UniversityUtrechtThe Netherlands
| | - Toshiyuki Usami
- Graduate School of HorticultureChiba UniversityMatsudo, Chiba271‐8510Japan
| | - Henk J. Schouten
- Laboratory of Plant BreedingWageningen University and ResearchWageningen6708 PBThe Netherlands
| | - Yuling Bai
- Laboratory of Plant BreedingWageningen University and ResearchWageningen6708 PBThe Netherlands
| | - Michael F. Seidl
- Laboratory of PhytopathologyWageningen University and ResearchWageningen6708 PBThe Netherlands
- Theoretical Biology and Bioinformatics Group, Department of BiologyUtrecht UniversityUtrechtThe Netherlands
| | - Bart P. H. J. Thomma
- Laboratory of PhytopathologyWageningen University and ResearchWageningen6708 PBThe Netherlands
- Cluster of Excellence on Plant Sciences (CEPLAS)University of Cologne, Botanical InstituteCologneGermany
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Cook DE, Kramer HM, Torres DE, Seidl MF, Thomma BPHJ. A unique chromatin profile defines adaptive genomic regions in a fungal plant pathogen. eLife 2020; 9:e62208. [PMID: 33337321 PMCID: PMC7781603 DOI: 10.7554/elife.62208] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 12/17/2020] [Indexed: 12/13/2022] Open
Abstract
Genomes store information at scales beyond the linear nucleotide sequence, which impacts genome function at the level of an individual, while influences on populations and long-term genome function remains unclear. Here, we addressed how physical and chemical DNA characteristics influence genome evolution in the plant pathogenic fungus Verticillium dahliae. We identified incomplete DNA methylation of repetitive elements, associated with specific genomic compartments originally defined as Lineage-Specific (LS) regions that contain genes involved in host adaptation. Further chromatin characterization revealed associations with features such as H3 Lys-27 methylated histones (H3K27me3) and accessible DNA. Machine learning trained on chromatin data identified twice as much LS DNA as previously recognized, which was validated through orthogonal analysis, and we propose to refer to this DNA as adaptive genomic regions. Our results provide evidence that specific chromatin profiles define adaptive genomic regions, and highlight how different epigenetic factors contribute to the organization of these regions.
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Affiliation(s)
- David E Cook
- Department of Plant Pathology, Kansas State UniversityManhattanUnited States
- Laboratory of Phytopathology, Wageningen University & ResearchWageningenNetherlands
| | - H Martin Kramer
- Laboratory of Phytopathology, Wageningen University & ResearchWageningenNetherlands
| | - David E Torres
- Laboratory of Phytopathology, Wageningen University & ResearchWageningenNetherlands
- Theoretical Biology & Bioinformatics Group, Department of Biology, Utrecht UniversityUtrechtNetherlands
| | - Michael F Seidl
- Laboratory of Phytopathology, Wageningen University & ResearchWageningenNetherlands
- Theoretical Biology & Bioinformatics Group, Department of Biology, Utrecht UniversityUtrechtNetherlands
| | - Bart P H J Thomma
- Laboratory of Phytopathology, Wageningen University & ResearchWageningenNetherlands
- University of Cologne, Institute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS)CologneGermany
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Torres DE, Oggenfuss U, Croll D, Seidl MF. Genome evolution in fungal plant pathogens: looking beyond the two-speed genome model. FUNGAL BIOL REV 2020. [DOI: 10.1016/j.fbr.2020.07.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Mukherjee S, Torres DE, Jakubikova E. HOMO inversion as a strategy for improving the light-absorption properties of Fe(ii) chromophores. Chem Sci 2017; 8:8115-8126. [PMID: 29568460 PMCID: PMC5855294 DOI: 10.1039/c7sc02926h] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 10/03/2017] [Indexed: 12/26/2022] Open
Abstract
Substitution of π-conjugated donor groups onto the polypyridine ligands in Fe(ii) complexes inverts the HOMO character and improves the light-absorption.
A computational study of a series of [Fe(tpy)2]2+ (tpy = 2,2′:6′,2′′-terpyridine) complexes is reported, where the tpy ligand is substituted at the 4, 4′, and 4′′ positions by electron donor (furan, thiophene, selenophene, NH2) and acceptor (carboxylic acid, NO2) groups. Using DFT and TD-DFT calculations, we show that the substitution of heterocyclic π donor groups onto the tpy ligand scaffold leads to marked improvement of the [Fe(tpy)2]2+ absorption properties, characterized by increased molar extinction coefficients, shift of absorption energies to longer wavelengths, and broadening of the absorption spectrum in the visible region. The observed changes in the light absorption properties are due to destabilization of ligand-centered occupied π orbital energies, thus increasing the interactions between the metal t2g (HOMO) and ligand π orbitals. Substitution of extended π-conjugated groups, such as thienothiophene and dithienothiophene, further destabilizes the ligand π orbital energies, resulting in a fully ligand-localized HOMO (i.e., HOMO inversion) and additional improvement of the light absorption properties. These results open up a new strategy to tuning the light absorption properties of Fe(ii)-polypyridines.
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Affiliation(s)
- Sriparna Mukherjee
- Department of Chemistry , North Carolina State University , Raleigh , NC 27695 , USA .
| | - David E Torres
- Wake STEM Early College High School , 715 Barbour Dr , Raleigh , NC 27603 , USA
| | - Elena Jakubikova
- Department of Chemistry , North Carolina State University , Raleigh , NC 27695 , USA .
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