Cyto-nuclear discordance in the phylogeny of <it>Ficus </it>section <it>Galoglychia </it>and host shifts in plant-pollinator associations
<p>Abstract</p> <p>Background</p> <p>Hybridization events are relatively common in vascular plants. However, the frequency of these events is unevenly distributed across the plant phylogeny. Plant families in which individual species are pollinated by specific pollinato...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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BMC
2009-10-01
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| Series: | BMC Evolutionary Biology |
| Online Access: | http://www.biomedcentral.com/1471-2148/9/248 |
| _version_ | 1819225782092824576 |
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| author | Santoni Sylvain Grout Cinderella Kjellberg Finn Renoult Julien P Khadari Bouchaïb |
| author_facet | Santoni Sylvain Grout Cinderella Kjellberg Finn Renoult Julien P Khadari Bouchaïb |
| author_sort | Santoni Sylvain |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p>Hybridization events are relatively common in vascular plants. However, the frequency of these events is unevenly distributed across the plant phylogeny. Plant families in which individual species are pollinated by specific pollinator species are predicted to be less prone to hybridization than other families. However, exceptions may occur within these families, when pollinators shift host-plant species. Indeed, host shifts are expected to increase the rate of hybridization events. Pollinators of <it>Ficus </it>section <it>Galoglychia </it>are suspected to have changed host repeatedly, based on several cases of incongruence between plant phylogeny and taxonomy, and insect phylogeny and taxonomy. We tracked cyto-nuclear discordance across section <it>Galoglychia </it>as evidence for hybridization. To achieve a proper global view, we first clarified the monophyly of section <it>Galoglychia </it>as it had been questioned by recent phylogenetic studies. Moreover, we investigated if fig size could be a factor facilitating host shifts.</p> <p>Results</p> <p>Phylogenetic chloroplast and nuclear results demonstrated the monophyly of section <it>Galoglychia</it>. Within section <it>Galoglychia</it>, we detected several cases of statistically significant cyto-nuclear discordance. Discordances concern both terminal nodes of the phylogenetic trees and one deep node defining relationships between subsections. Because nuclear phylogeny is congruent with morphological taxonomy, discordances were caused by the chloroplast phylogeny. Introgressive hybridization was the most likely explanation for these discordances. We also detected that subsections pollinated by several wasp genera had smaller figs and were pollinated by smaller wasps than subsections pollinated by a single wasp genus.</p> <p>Conclusion</p> <p>As hypothesized, we discovered evidences of past hybridization in <it>Ficus </it>section <it>Galoglychia</it>. Further, introgression was only detected in subsections presenting incongruence between plant and pollinator phylogenies and taxonomy. This supports the hypothesis that host shift is the cause for plant-pollinator incongruence. Moreover, small fig size could facilitate host shifts. Eventually, this study demonstrates that non-coding chloroplast markers are valuable to resolve deep nodes in <it>Ficus </it>phylogeny.</p> |
| first_indexed | 2024-12-23T10:15:04Z |
| format | Article |
| id | doaj.art-a032a55a66b846dd811a25acbc9a4c47 |
| institution | Directory Open Access Journal |
| issn | 1471-2148 |
| language | English |
| last_indexed | 2024-12-23T10:15:04Z |
| publishDate | 2009-10-01 |
| publisher | BMC |
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| series | BMC Evolutionary Biology |
| spelling | doaj.art-a032a55a66b846dd811a25acbc9a4c472022-12-21T17:50:51ZengBMCBMC Evolutionary Biology1471-21482009-10-019124810.1186/1471-2148-9-248Cyto-nuclear discordance in the phylogeny of <it>Ficus </it>section <it>Galoglychia </it>and host shifts in plant-pollinator associationsSantoni SylvainGrout CinderellaKjellberg FinnRenoult Julien PKhadari Bouchaïb<p>Abstract</p> <p>Background</p> <p>Hybridization events are relatively common in vascular plants. However, the frequency of these events is unevenly distributed across the plant phylogeny. Plant families in which individual species are pollinated by specific pollinator species are predicted to be less prone to hybridization than other families. However, exceptions may occur within these families, when pollinators shift host-plant species. Indeed, host shifts are expected to increase the rate of hybridization events. Pollinators of <it>Ficus </it>section <it>Galoglychia </it>are suspected to have changed host repeatedly, based on several cases of incongruence between plant phylogeny and taxonomy, and insect phylogeny and taxonomy. We tracked cyto-nuclear discordance across section <it>Galoglychia </it>as evidence for hybridization. To achieve a proper global view, we first clarified the monophyly of section <it>Galoglychia </it>as it had been questioned by recent phylogenetic studies. Moreover, we investigated if fig size could be a factor facilitating host shifts.</p> <p>Results</p> <p>Phylogenetic chloroplast and nuclear results demonstrated the monophyly of section <it>Galoglychia</it>. Within section <it>Galoglychia</it>, we detected several cases of statistically significant cyto-nuclear discordance. Discordances concern both terminal nodes of the phylogenetic trees and one deep node defining relationships between subsections. Because nuclear phylogeny is congruent with morphological taxonomy, discordances were caused by the chloroplast phylogeny. Introgressive hybridization was the most likely explanation for these discordances. We also detected that subsections pollinated by several wasp genera had smaller figs and were pollinated by smaller wasps than subsections pollinated by a single wasp genus.</p> <p>Conclusion</p> <p>As hypothesized, we discovered evidences of past hybridization in <it>Ficus </it>section <it>Galoglychia</it>. Further, introgression was only detected in subsections presenting incongruence between plant and pollinator phylogenies and taxonomy. This supports the hypothesis that host shift is the cause for plant-pollinator incongruence. Moreover, small fig size could facilitate host shifts. Eventually, this study demonstrates that non-coding chloroplast markers are valuable to resolve deep nodes in <it>Ficus </it>phylogeny.</p>http://www.biomedcentral.com/1471-2148/9/248 |
| spellingShingle | Santoni Sylvain Grout Cinderella Kjellberg Finn Renoult Julien P Khadari Bouchaïb Cyto-nuclear discordance in the phylogeny of <it>Ficus </it>section <it>Galoglychia </it>and host shifts in plant-pollinator associations BMC Evolutionary Biology |
| title | Cyto-nuclear discordance in the phylogeny of <it>Ficus </it>section <it>Galoglychia </it>and host shifts in plant-pollinator associations |
| title_full | Cyto-nuclear discordance in the phylogeny of <it>Ficus </it>section <it>Galoglychia </it>and host shifts in plant-pollinator associations |
| title_fullStr | Cyto-nuclear discordance in the phylogeny of <it>Ficus </it>section <it>Galoglychia </it>and host shifts in plant-pollinator associations |
| title_full_unstemmed | Cyto-nuclear discordance in the phylogeny of <it>Ficus </it>section <it>Galoglychia </it>and host shifts in plant-pollinator associations |
| title_short | Cyto-nuclear discordance in the phylogeny of <it>Ficus </it>section <it>Galoglychia </it>and host shifts in plant-pollinator associations |
| title_sort | cyto nuclear discordance in the phylogeny of it ficus it section it galoglychia it and host shifts in plant pollinator associations |
| url | http://www.biomedcentral.com/1471-2148/9/248 |
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