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1.  Cytogenetic characterization and genome size of the medicinal plant Catharanthus roseus (L.) G. Don 
AoB Plants  2012;2012:pls002.
The genome size and organization of the important medicinal plant Catharanthus roseus is shown to correspond to 1C = 0.76 pg (~738 Mbps) and 2n = 16 chromosomes. The data provide a sound basis for future studies including cytogenetic mapping, genomics and breeding.
Background and aims
Catharanthus roseus is a highly valuable medicinal plant producing several terpenoid indole alkaloids (TIAs) with pharmaceutical applications, including the anticancer agents vinblastine and vincristine. Due to the interest in its TIAs, C. roseus is one of the most extensively studied medicinal plants and has become a model species for the study of plant secondary metabolism. However, very little is known about the cytogenetics and genome size of this species, in spite of their importance for breeding programmes, TIA genetics and emerging genomic research. Therefore, the present paper provides a karyotype description and fluorescence in situ hybridization (FISH) data for C. roseus, as well as a rigorous characterization of its genome size.
Methodology
The organization of C. roseus chromosomes was characterized using several DNA/chromatin staining techniques and FISH of rDNA. Genome size was investigated by flow cytometry using an optimized methodology.
Principal results
The C. roseus full chromosome complement of 2n = 16 includes two metacentric, four subtelocentric and two telocentric chromosome pairs, with the presence of a single nucleolus organizer region in chromosome 6. An easy and reliable flow cytometry protocol for nuclear genome analysis of C. roseus was optimized, and the C-value of this species was estimated to be 1C = 0.76 pg, corresponding to 738 Mbp.
Conclusions
The organization and size of the C. roseus genome were characterized, providing an important basis for future studies of this important medicinal species, including further cytogenetic mapping, genomics, TIA genetics and breeding programmes.
doi:10.1093/aobpla/pls002
PMCID: PMC3292738  PMID: 22479673
2.  A vacuolar class III peroxidase and the metabolism of anticancer indole alkaloids in Catharanthus roseus 
Plant Signaling & Behavior  2008;3(10):899-901.
Plants possess a unique metabolic diversity commonly designated as secondary metabolism, of which the anticancer alkaloids from Catharanthus roseus are among the most studied. Recently, in a classical function-to-protein-to-gene approach, we have characterized the main class III peroxidase (Prx) expressed in C. roseus leaves, CrPrx1, implicated in a key biosynthetic step of the anticancer alkaloids. We have shown the vacuolar sorting determination of CrPrx1 using GFP fusions and we have obtained further evidence supporting the role of this enzyme in alkaloid biosynthesis, indicating the potential of CrPrx1 as a molecular tool for the manipulation of alkaloid metabolism. Here, we discuss how plant cells may regulate Prx reactions. In fact, Prxs form a large multigenic family whose members accept a broad range of substrates and, in their two subcellular localizations, the cell wall and the vacuole, Prxs co-locate with a large variety of secondary metabolites which can be accepted as substrates. How then, are Prx reactions regulated? Localization data obtained in our lab suggest that arabinogalactan proteins (AGPs) and Prxs may be associated in membrane microdomains, evocative of lipid rafts. Whether plasma membrane and/or tonoplast microcompartmentation involve AGPs and Prxs and whether this enables metabolic channeling determining Prx substrate selection are challenging questions ahead.
PMCID: PMC2634410  PMID: 19704535
class III peroxidases; CrPrx1; indole alkaloids; vacuole; secondary metabolites; arabinogalactan proteins; lipid rafts

Results 1-2 (2)