Abstract
The gene cluster rps12/rps7/ΨndhB of the plastome from the holoparasitic plant Cuscuta europaea has been analysed at the nucleotide level. A comparison with the homologous region of the plastome from the closely related parasite Cuscuta reflexa reveals a complete loss of the cis-spliced intron of the rps12 gene in addition to a drastic size reduction of the ndhB pseudogene. It is demonstrated by RT-PCR analysis that the entire gene cluster is transcribed in the form of a multicistronic transcript which also includes the sequences encoded by the ndhB pseudogene. A cDNA containing the correctly transspliced exon 1 of the rps12 transcript can also be amplified. This shows that trans-splicing of the rps12 transcript persists in the plastids of the holoparasite despite the loss of the cis-spliced intron and the loss of many other gene functions. The rps12 and rps7 genes, therefore, still appear to code for functional ribosomal proteins CS12 and CS7, respectively. The conservation of apparently intact ribosomal-protein genes from which correctly processed transcripts are produced is taken as evidence that the translational apparatus of the plastids is still functional and necessary for the expression of the genes remaining in the reduced plastome of a parasitic plant.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
de Pamphilis CW, Palmer JD (1990) Loss of photosynthetic and chlororespiratory genes from the plastid genome of a parasitic flowering plant. Nature 348:337–339
Dellaporta SL, Wood J, Hicks JB (1983) A plant DNA minipreparation: version II. Plant Mol Biol Rep 1:19–21
Downie SR, Olmstead RG, Zurawski G, Soltis DE, Soltis PS, Watson JC, Palmer JD (1991) Six independent losses of the chloroplast DNA rpl2 intron in dicotyledons: molecular and phylogenetic implications. Evolution 45:1245–1259
Faßbender S, Brühl KH, Ciriacy M, Kück U (1994) Reverse transcriptase activity of an intron-encoded polypeptide. EMBO J 13:2075–2083
Felsenstein J (1993) PHYLIP (Phylogenetic Inference Package) version 3.5c. Distributed by the author. Department of Genetics, University of Washington, Seattle
Giese K, Subramanian AR, Larrinua IM, Bogorad L (1987) Nucleotide sequence, promoter analysis, and linkage mapping of the unusually organized operon encoding ribosomal proteins S7 and S12 in maize chloroplast. J Biol Chem 262:15251–15255
Haberhausen G, Zetsche K (1994) Functional loss of all ndh genes in an otherwise relatively unaltered plastid genome of the holoparasitic flowering plant Cuscuta reflexa. Plant Mol Biol 24: 217–222
Hiratsuka J, Shimada H, Whittier R, Ishibashi T, Sakamoto M, Mori M, Kondo C, Honji Y, Sun C-R, Meng B-Y, Li Y-Q, Kanno A, Nishizawa Y, Hirai A, Shinozaki K, Sugiura M (1989) The complete sequence of the rice (Oryza sativa) chloroplast genome: intermolecular recombination between distinct tRNA genes accounts for a major plastid DNA inversion during the evolution of the cereals. Mol Gen Genet 217:185–194
Hoot SB, Palmer JD (1994) Structural rearrangements, including parallel inversions, within the chloroplast genome of Anemone and related genera. J Mol Evol 38:274–281
Igloi GL, Meinke A, Döry I, Kössel H (1990) Nucleotide sequence and the maize chloroplast rpoB/C1/C2 operon: comparison between the derived protein primary structures from various organisms with respect to functional domains. Mol Gen Genet 221: 379–394
Machado MA, Zetsche K (1990) A structural, functional and molecular analysis of plastids of the holoparasites Cuscuta reflexa and Cuscuta europaed. Planta 181:91–96
Maier RM, Hoch B, Zeltz P, Kössel H (1992) Internal editing of the maize chloroplast ndhA transcript restores codons for conserved amino acids. Plant Cell 4:609–616
Mohr G, Perlman PS, Lambowitz AM (1993) Evolutionary relationships among group-II intron-encoded proteins and identification of a conserved domain that may be related to maturase function. Nucleic Acids Res 21:4991–4997
Neckermann K, Zeltz P, Igloi GL, Kössel H, Maier RM (1994) The role of RNA editing in the conservation of start codons in chloroplast genomes. Gene 146:177–182
Ohyama K, Fukuzawa H, Kohchi T, Shirai H, Sano S, Umesoso K, Shiki Y, Takeuchi M, Chang Z, Aota S, Inokuchi H, Ozeki H (1986) Chloroplast gene organization deduced from the complete sequence of liverwort Marchantia polymorpha chloroplast DNA. Nature 322:572–574
Palmer JD (1990) Contrasting modes and tempos of genome evolution in land-plant organelles. Trends Genet 6:115–120
Scherer S (1990) Do photosynthetic and respiratory electron transport chains share redox proteins. Trends Biochem 15:458–462
Shimada H, Sugiura M (1991) Fine structural features of the chloroplast genome: comparison of the sequenced chloroplast genomes. Nucleic Acids Res 19:983–995
Shinozaki K, Ohme M, Tanaka M, Wakasugi T, Hayashida N, Matsubayashi T, Zaita N, Chunwongse J, Obokata J, Yamaguchi-Shinozaki K, Ohto C, Torazawa K, Meng BY, Sugita M, Deno H, Kamogashira T, Yamada K, Kusuda J, Takaiwa F, Kato A, Tohdoh N, Shimada H, Sugiura M (1986) The complete nucleotide sequence of the tobacco chloroplast genome:its gene organization and expression. EMBO J 5:2043–2049
Walker JE (1992) The NADH:ubiquinone oxidoreductase (complex I) of respiratory chains. Quart Rev Biophys 25:253–324
Wolfe KH, Morden CW, Ems SC, Palmer JD (1992) Rapid evolution of the plastid translational apparatus in a non-photosynthetic plant: loss or accelerated sequence evolution of tRNA and ribosomal protein genes. J Mol Evol 35:304–317
Author information
Authors and Affiliations
Additional information
This paper is dedicated to Prot. Dr. Peter Sitte on the occasion of his 65th birthday
Rights and permissions
About this article
Cite this article
Freyer, R., Neckermann, K., Maier, R.M. et al. Structural and functional analysis of plastid genomes from parasitic plants: loss of an intron within the genus Cuscuta . Curr Genet 27, 580–586 (1995). https://doi.org/10.1007/BF00314451
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00314451