Molecular cloning of Tulipa fosteriana rDNA and subsequent FISH analysis yields cytogenetic organization of 5S rDNA and 45S rDNA in T. gesneriana and T. fosteriana
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In this study, Tulipa fosteriana was found to contain 45S rDNA repeat units of 9.7 and 9.5 kb, in which at least 7 types of 45S rDNAs were identified by restriction site analysis. For 5S rDNA, repeat units ranging from 364 bp to 396 bp were identified. The diploid cultivars (2n = 2x = 24) ‘Christmas Dream’ and ‘Queen of Night,’ representing the horticultural group T. gesneriana, and ‘Red Emperor’, belonging to T. fosteriana, were compared cytogenetically using cloned 5S and 45S rDNAs. Fluorescence in situ hybridization (FISH) analysis identified many rDNA sites located on each chromosome in the diploid genomes. For example, we identified 71 sites of 5S rDNA and 10 sites of 45S rDNA in ‘Red Emperor’. Additionally, FISH analyses enabled construction of karyotypes for these cultivars. Karyotype comparison of T. gesneriana cultivars showed conservation of repetitive rDNA unit positioning. A clear difference in chromosome size and signal pattern was observed between T. gesneriana and T. fosteriana cultivars. Here we demonstrate the unique nature of the highly repeated 5S rDNA units in these Tulipa species and the usefulness of FISH karyotyping with cloned 5S and 45S rDNAs to clearly distinguish between chromosomes from T. gesneriana and T. fosteriana.
KeywordsChromosome identification Fluorescence in situ hybridization Repetitive DNA Tulipa
The authors are grateful to Dr. F. Takaiwa of the National Institute of Agrobiological Resources, Japan, for providing the rice 45S rDNA clone. This work was partially supported by the Japanese Society for the Promotion of Science (JSPS fellowship award to A.M., 2005–2007, No. P 05186).
- Appels R, Honeycutt RL (1986) rDNA: evolution over a billion years. In: Dutta SK (ed) DNA systematics.Vol. I, II. CRC Press Inc, Boca RatonGoogle Scholar
- Bachmann K (1992) Nuclear DNA markers in angiosperm taxonomy. Acta Bot Neerl 39:369–384Google Scholar
- Bryan EB (2002) Bulbs. Timber Press, Inc, Portland, Oregon, pp 454–462Google Scholar
- Dana KJ, Workman R, Coryell V, Keim P (1996) 5S rRNA genes in tribe Phaseoleae: array size, number and dynamics. Genome 39:445–455Google Scholar
- Killingback S (1990) Tulips—an illustrated identifier and guide to their cultivation. Apple Press, London, pp 9–13Google Scholar
- Sadder MT, Weber G (2001) Karyotype of Maize (Zea mays L.) mitotic metaphase chromosomes as revealed by fluorescence in situ hybridization (FISH) with cytogenetic DNA markers. Plant Mol Biol Rep 19:117–123Google Scholar
- Sayama H, Moug T, Nishimura Y (1982) Cytological study in Tulipa gesneriana and T. fosteriana. Jpn J Breed 32:26–34Google Scholar
- Schaal BA, Leverich WJ, Nieto-Sotelo J (1987) Ribosomal DNA variation in the native plant Phlox divaricata. Mol Biol Evol 4:611–621Google Scholar
- Van Tuyl JM, Van Creij MGM (2005) Tulipa gesneriana and Tulipa hybrids. In: flower breeding and genetics: issues, challenges and opportunities for 21st century, Springer Verlag, Chapter 23, pp 613–637Google Scholar