Genome size variation in Orchidaceae subfamily Apostasioideae: filling the phylogenetic gap

Authors

  • Jana Jersáková,

    1. Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
    2. CzechGlobe, Academy of Sciences of the Czech Republic, Brno, Czech Republic
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  • Pavel Trávníček,

    1. Department of Botany, Faculty of Science, Charles University in Prague, Prague, Czech Republic
    2. Institute of Botany, Academy of Sciences of the Czech Republic, Czech Republic
    3. Biotechnological Centre, Faculty of Agriculture, University of South Bohemia, České Budějovice, Czech Republic
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  • Barbora Kubátová,

    1. Biotechnological Centre, Faculty of Agriculture, University of South Bohemia, České Budějovice, Czech Republic
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  • Jana Krejčíková,

    1. Department of Botany, Faculty of Science, Charles University in Prague, Prague, Czech Republic
    2. Institute of Botany, Academy of Sciences of the Czech Republic, Czech Republic
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  • Tomáš Urfus,

    1. Department of Botany, Faculty of Science, Charles University in Prague, Prague, Czech Republic
    2. Institute of Botany, Academy of Sciences of the Czech Republic, Czech Republic
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  • Zhong-Jian Liu,

    1. Shenzhen Key Laboratory for Orchid Conservation and Utilization, The National Orchid Conservation Center of China, The Orchid Conservation and Research Center of Shenzhen, Shenzhen, China
    2. The Center for Biotechnology and BioMedicine, Graduate School at Shenzhen, Tsinghua University, Shenzhen, China
    3. College of Forestry, South China Agricultural University, Guangzhou, China
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  • Anthony Lamb,

    1. Kota Kinabalu, Sabah, Malaysia
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  • Jan Ponert,

    1. Department of Experimental Plant Biology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
    2. Prague Botanical Garden, Prague, Czech Republic
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  • Katharina Schulte,

    1. Australian Tropical Herbarium and Centre for Tropical Biodiversity and Climate Change, James Cook University, Smithfield, Queensland, Australia
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  • Vladislav Čurn,

    1. Biotechnological Centre, Faculty of Agriculture, University of South Bohemia, České Budějovice, Czech Republic
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  • Jan Vrána,

    1. Centre of the Haná Region for Biotechnological and Agricultural Research, Institute of Experimental Botany, Olomouc, Czech Republic
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  • Ilia J. Leitch,

    1. Jodrell Laboratory, Royal Botanic Gardens, Surrey, UK
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  • Jan Suda

    Corresponding author
    1. Department of Botany, Faculty of Science, Charles University in Prague, Prague, Czech Republic
    2. Institute of Botany, Academy of Sciences of the Czech Republic, Czech Republic
    • Biotechnological Centre, Faculty of Agriculture, University of South Bohemia, České Budějovice, Czech Republic
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Corresponding author. E-mail: suda@natur.cuni.cz

Abstract

With more than 160-fold variation, Orchidaceae are currently the most diverse angiosperm family with respect to the amount of nuclear DNA. This study provides first genome size estimates for approximately 50% of species currently recognized in subfamily Apostasioideae, which is sister to the other four orchid subfamilies. The estimated 1C-values range from 0.38 pg in Apostasia nuda to 5.96 pg in Neuwiedia zollingeri var. javanica, a nearly 16-fold range. The two genera show non-overlapping genome sizes, with those in Apostasia being distinctly smaller than those in Neuwiedia. In fact, most Apostasia spp. are at the lower end of the range of orchid C-values. Observed discontinuities in DNA amounts in genera most probably reflect interspecific variation in ploidy. In addition to ploidy heterogeneity in N. zollingeri var. javanica, intraspecific variation in genome size (up to 17.7%) was also detected in some species; this can be plausibly related to the incidence of different geographical variants or unrecognized taxonomic heterogeneity. The AT content varied from 62.6 to 66.0%, which is in the upper range recorded for angiosperms. The genome size data obtained in this study fill a major phylogenetic gap in Orchidaceae and show that (very) small genomes prevail in subfamily Apostasioideae. © 2013 The Linnean Society of London

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