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Liu ZF, Ci XQ, Zhang SF, Zhang XY, Zhang X, Dong LN, Conran JG, Li J. Diverse Host Spectrum and the Parasitic Process in the Pantropical Hemiparasite Cassytha filiformis L. (Lauraceae) in China. DIVERSITY 2023. [DOI: 10.3390/d15040492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
Abstract
Many hemiparasites attach to a range of different host species, resulting in complex parasite–host interactions. Comprehensive molecular phylogenies allow the investigation of evolutionary relationships between these host plants. We surveyed the hosts of the laurel dodder (Cassytha filiformis, Lauraceae) in China, representing 184 species from 146 genera, 67 families, and spanning flowering plants, conifers, and ferns, using host phylogenetic relationships to investigate the susceptibility to attack by this hemiparasitic plant among the vascular plants. The process of produced well-formed haustoria by C. filiformis was also observed in detail for six different hosts. Our results show that C. filiformis grows mainly on trees and shrubs from phylogenetically divergent members of the rosid and asterid eudicot clades, often attacking multiple adjacent hosts simultaneously, and forming extensive colonies. However, whether and to what extent transitions between C. filiformis and host plants occur remain unclear. Physiological evidence for the complex parasite–host species interactions need to be studied in the future.
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Garrett P, Becher H, Gussarova G, dePamphilis CW, Ness RW, Gopalakrishnan S, Twyford AD. Pervasive Phylogenomic Incongruence Underlies Evolutionary Relationships in Eyebrights ( Euphrasia, Orobanchaceae). FRONTIERS IN PLANT SCIENCE 2022; 13:869583. [PMID: 35720561 PMCID: PMC9197813 DOI: 10.3389/fpls.2022.869583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 04/19/2022] [Indexed: 06/15/2023]
Abstract
Disentangling the phylogenetic relationships of taxonomically complex plant groups is often mired by challenges associated with recent speciation, hybridization, complex mating systems, and polyploidy. Here, we perform a phylogenomic analysis of eyebrights (Euphrasia), a group renowned for taxonomic complexity, with the aim of documenting the extent of phylogenetic discordance at both deep and at shallow phylogenetic scales. We generate whole-genome sequencing data and integrate this with prior genomic data to perform a comprehensive analysis of nuclear genomic, nuclear ribosomal (nrDNA), and complete plastid genomes from 57 individuals representing 36 Euphrasia species. The species tree analysis of 3,454 conserved nuclear scaffolds (46 Mb) reveals that at shallow phylogenetic scales postglacial colonization of North Western Europe occurred in multiple waves from discrete source populations, with most species not being monophyletic, and instead combining genomic variants from across clades. At a deeper phylogenetic scale, the Euphrasia phylogeny is structured by geography and ploidy, and partially by taxonomy. Comparative analyses show Southern Hemisphere tetraploids include a distinct subgenome indicative of independent polyploidy events from Northern Hemisphere taxa. In contrast to the nuclear genome analyses, the plastid genome phylogeny reveals limited geographic structure, while the nrDNA phylogeny is informative of some geographic and taxonomic affinities but more thorough phylogenetic inference is impeded by the retention of ancestral polymorphisms in the polyploids. Overall our results reveal extensive phylogenetic discordance at both deeper and shallower nodes, with broad-scale geographic structure of genomic variation but a lack of definitive taxonomic signal. This suggests that Euphrasia species either have polytopic origins or are maintained by narrow genomic regions in the face of extensive homogenizing gene flow. Moreover, these results suggest genome skimming will not be an effective extended barcode to identify species in groups such as Euphrasia, or many other postglacial species groups.
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Affiliation(s)
- Phen Garrett
- GLOBE Institute, University of Copenhagen, Copenhagen, Denmark
| | - Hannes Becher
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Galina Gussarova
- Natural History Museum, University of Oslo, Oslo, Norway
- Botany Department, Faculty of Biology and Soil Science, St Petersburg State University, St Petersburg, Russia
- Tromsø University Museum, University of Tromsø, Tromsø, Norway
| | - Claude W. dePamphilis
- Department of Biology and Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, United States
| | - Rob W. Ness
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, Canada
| | | | - Alex D. Twyford
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
- Royal Botanic Garden Edinburgh, Edinburgh, United Kingdom
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