Hybridization in Compositae
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Hybridization in Compositae Dr. Edward Schilling University of Tennessee Tennessee – not Texas, but we still grow them big! [email protected] Ayres Hall – University of Tennessee campus in Knoxville, Tennessee University of Tennessee Leucanthemum vulgare – Inspiration for school colors (“Big Orange”) Compositae – Hybrids Abound! Changing view of hybridization: once consider rare, now known to be common in some groups Hotspots (Ellstrand et al. 1996. Proc Natl Acad Sci, USA 93: 5090-5093) Comparison of 5 floras (British Isles, Scandanavia, Great Plains, Intermountain, Hawaii): Asteraceae only family in top 6 in all 5 Helianthus x multiflorus Overview of Presentation – Selected Aspects of Hybridization 1. More rather than less – an example from the flower garden 2. Allopolyploidy – a changing view 3. Temporal diversity – Eupatorium (thoroughworts) 4. Hybrid speciation/lineages – Liatrinae (blazing stars) 5. Complications for phylogeny estimation – Helianthinae (sunflowers) Hybrid: offspring between two genetically different organisms Evolutionary Biology: usually used to designated offspring between different species “Interspecific Hybrid” “Species” – problematic term, so some authors include a description of their species concept in their definition of “hybrid”: Recognition of Hybrids: 1. Morphological “intermediacy” Actually – mixture of discrete parental traits + intermediacy for quantitative ones In practice: often a hybrid will also exhibit traits not present in either parent, transgressive Recognition of Hybrids: 1. Morphological “intermediacy” Actually – mixture of discrete parental traits + intermediacy for quantitative ones In practice: often a hybrid will also exhibit traits not present in either parent, transgressive 2. Genetic “additivity” Presence of genes from each parent Recognition of Hybrids: 1. Morphological “intermediacy” Actually – mixture of discrete parental traits + intermediacy for quantitative ones In practice: often a hybrid will also exhibit traits not present in either parent, transgressive 2. Genetic “additivity” Presence of genes from each parent 3. Sterility [particularly in annuals] and inviability [gene interactions!] Recognition of Hybrids: 1. Morphological “intermediacy” Actually – mixture of discrete parental traits + intermediacy for quantitative ones In practice: often a hybrid will also exhibit traits not present in either parent, transgressive 2. Genetic “additivity” Presence of genes from each parent 3. Sterility [particularly in annuals] and inviability [gene interactions!] 4. Conflicting phylogenies based on different genes Plants: plastid DNA vs. nuclear DNA (often ITS/ETS loci) Note – DNA sequence data have made possible increased sensitivity to detect hybrids/past hybridization Internal Transcribed Spacer Region – nuclear ribosomal DNA ITS REGION ITS5 79F ITS1 ITS2 18S rDNA 5.8S 26S rDNA 5.8sR ITS4 Internal Transcribed Spacer Region – nuclear ribosomal DNA ITS REGION ITS5 79F ITS1 ITS2 18S rDNA 5.8S 26S rDNA 5.8sR ITS4 Internal Transcribed Spacer Region – nuclear ribosomal DNA ITS REGION ITS5 79F ITS1 ITS2 18S rDNA 5.8S 26S rDNA 5.8sR ITS4 ITS – ok for phylogeny – great for identification Example – F1 hybrids from the garden: Example – F1 hybrids from the garden: What is Eupatorium auromaticum „Joicus Variegated‟? Note – Eupatorium aromaticum = Ageratina aromatica Eupatorieae ITS Phylogeny Eupatorium restricted to ca. 30 spp. of North America/Asia Flyriella parryi Perityleae Outgroup Viereckia tamaulipensis Ageratina herbacea Grisebachianthus libanotica Ageratina glechnophylla Grisebachianthus lantanifol. Ageratina aromatica Koanophyllon polystichum Ageratina wrightii Koanophyllon ayapanoides Ageratina (7 spp) Ageratum (6 spp) Pachythamnus crassirameus Conoclinium (5 spp) Kaunia saltensis Tamaulipa azurea Neomirandea araliifolium Critonia sexangularis Hofmeisteria (4 spp) Kyrsteniopsis spinacifolia Bartlettina (4 spp) Chromolaena (4 spp) Stevia plummerae Chromolaena odorata Stevia rebaudiana Chromolaena laevigata Microspermum nummular. Chromolaena morii Shinnersia rivularis Praxelis kleinioides Trichocoronis wrightii Praxelis decumbens Sclerolepis uniflora Aristiguieta salvia Mikania (8 spp) Isocarpha oppositifolia Brickellia (9 spp) Adenostemma involucratum Brickellia problematica Gyptis tanacetifolia Brickellia (12 spp) Bejaranoa balansae Pleurocoronis pluriseta Barrosoa betonaecifolia Malperia tenuis Platypodanthera mellisifol. Brickelliastrum fendleri Trichogonia menthaefolia Carminatia tenuiflora Trichogonia sp. Eupatorium (30 spp) Trichogonia salvaefolia Eutrochium (5 spp) Trichogonia sp. Garberia heterophylla Conocliniopsis prassifolius Trilisa paniculata Acritopappus hagei Litrisa carnosa Bishopiella elegans Hartwrightia floridana Litothamnus ellipticus Carphephorus corymbosus Campuloclinium chlorolepis Carphephorus tomentosus Campuloclinium hirsutum Liatris (25 spp) Heterocondylus pumilus Steviopsis vigintiseta Acanthostyles buniifolius Peteravenia malvaefolia Symphyopappus brasiliensis Campovassouria cruciata Graziela dimorpholepis Neocabreria serrulata Ophryosporus triangularis Names in Green – Eupatorium s.l. Helogyne tacaquirensis Eupatorieae ITS Phylogeny Eupatorium restricted to ca. 30 spp. of North America/Asia Flyriella parryi Perityleae Outgroup Viereckia tamaulipensis Ageratina herbacea Grisebachianthus libanotica Ageratina glechnophylla Grisebachianthus lantanifol. Ageratina aromatica Koanophyllon polystichum Ageratina wrightii Koanophyllon ayapanoides Ageratina (7 spp) Ageratum (6 spp) Pachythamnus crassirameus Conoclinium (5 spp) Kaunia saltensis Tamaulipa azurea Neomirandea araliifolium Critonia sexangularis Hofmeisteria fasciculata Kyrsteniopsis spinacifolia Bartlettina (4 spp) Chromolaena (4 spp) Stevia plummerae Chromolaena odorata Stevia rebaudiana Chromolaena laevigata Microspermum nummular. Chromolaena morii Shinnersia rivularis Praxelis kleinioides Trichocoronis wrightii Praxelis decumbens Sclerolepis uniflora Aristiguieta salvia Mikania scandens Isocarpha oppositifolia Brickellia coulteri Adenostemma involucratum Brickellia problematica Gyptis tanacetifolia Brickellia grandiflora Bejaranoa balansae Pleurocoronis pluriseta Barrosoa betonaecifolia Malperia tenuis Platypodanthera mellisifol. Brickelliastrum fendleri Trichogonia menthaefolia Carminatia tenuiflora Trichogonia sp. Eupatorium (30 spp) Trichogonia salvaefolia Eutrochium (5 spp) Trichogonia sp. Garberia heterophylla Conocliniopsis prassifolius Trilisa paniculata Acritopappus hagei Litrisa carnosa Bishopiella elegans Hartwrightia floridana Litothamnus ellipticus Carphephorus corymbosus Campuloclinium chlorolepis Carphephorus tomentosus Campuloclinium hirsutum Liatris (25 spp) Heterocondylus pumilus Steviopsis vigintiseta Acanthostyles buniifolius Peteravenia malvaefolia Symphyopappus brasiliensis Campovassouria cruciata Graziela dimorpholepis Neocabreria serrulata Ophryosporus triangularis Helogyne tacaquirensis What is “Eupatorium (Ageratina) auromaticum „Joicus Variegated‟”? ITS-2 sequence data – “Eupatorium auromaticum” = hybrid Eupatorium serotinum / E. altissimum Direction of sequencing “stutter” caused by length polymorphism Eupatorium “auromaticum” Eupatorium serotinum Eupatorium altissimum 2 bp insertion vs. all other Eupatorium Hybrids in the Garden – Conclusions: 1. Hybrids are common 2. Hybrids are more detectable with molecular tools 3. Caution in using material from Botanical Gardens! “Eupatorium greggii” – Conoclinium “Solidaster luteus” – Solidago “Conoclinium coelestinum alba” – dissectum x C. coelestinum canadensis x S. ptarmicoides Conoclinium coelestinum x C. dichotomum Outcome of Hybridization: allopolyploidy Allopolyploidy 2 diploid parents - Species 1 (AA) and Species 2 (BB) F1 hybrid is sterile - chromosomes don‟t pair normally AA Chromosome AB AABB doubling BB Diploid Sterile Fertile parents hybrid tetraploid NOTE: tetraploid is reproductively isolated from parents -> potential for immediate speciation Tragopogon Polyploid Complex Fig. 11-13 Raven et al., Biology of Plants, 7th ed. Tragopogon Polyploid Complex T. porrifolius PP 3 Parent Species – All Eurasian Natives All diploid x=6 c‟somes T. dubius T. pratensis (2n=12) DD SS Tragopogon Polyploid Complex T. porrifolius New In North Polyploid America Species – after 1930 PPxDD PD T. mirus Hybrid PPDD T. dubius T. pratensis 2n=24 DD SS Tragopogon Polyploid Complex T. porrifolius New In North Polyploid America Species – after 1930 T. mirus 2 new species! Hybrids T. pratensis New T. dubius Polyploid Species T. miscellus Outcome of Hybridization: allopolyploidy How frequently does polyploidy lead to an entirely new evolutionary lineage? New genomic data suggest that this may be more significant than suspected. Ancestral polyploidy events in seed plants and angiosperms. YN Jiao et al. Nature 473, 97-100 (2011) doi:10.1038/nature09916 Whole Genome Duplication in Compositae? J. C. Semple & K. Watanabe, Systematics, Evolution & Biogeography of Compositae, 2009. Whole Genome Duplication in Compositae? J. C. Semple & K. Watanabe, Systematics, Evolution & Biogeography of Compositae, 2009. Phylogeny of Compositae tribes and outgroups displaying observed paleopolyploid events and the rapid radiation of tribes. Barker M S et al. Mol Biol Evol 2008;25:2445-2455 © The Author 2008. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: [email protected] Outcome of Hybridization: allopolyploidy + apomixis apomictic