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Cytogenetic characterization of Centaurea solstitialis from Croatia

Centaurea genus is one of the largest in the Asteraceae family, containing at least 400 species with about 80 of them listed in Croatia, comprising 27 endemics. Although these plants are morphologically well described, there are occasional doubts in their botanical systematics. Recent promising approaches in botanical systematics include also genome size and detailed chromosome characterization, using methods for visualization of specific DNA sequences on chromosomes as GC- or AT- rich regions and rDNA. The essential oil composition may be used in chemotaxonomy of the species that contributes previous data on morphology and cytogenetics. Centaurea solstitialis L. is world spread invasive species, originating from Middle East, and well known on medicinal use in Turkey ethno pharmacology. Detailed cytogenetic study and essential oil phytochemical profile of C. solstitialis from Croatia were reported for the first time. The cytogenetic characterization of Centaurea solstitialis was assessed using flow cytometry, fluorochrome banding and Fluorescence in situ hybridization. Flow cytometry method, according to Marie and Brown (1993) were used to assess the total DNA amount. It showed karyotype of 2n=16 chromosomes, organized in four pairs of metacentric, two pairs of submetacentric and two pairs of subtelocentric chromosomes. Physical mapping of two rDNA probes revealed two loci of 35S and one locus of 5S rRNA genes. Chromomycin fluorochrome banding revealed that all rDNA loci were GC rich. The genome size (2C-value) of 1.95 pg classes this species in the group of very small genomes. Identification of the composition of the volatile oil was assessed with gas chromatography and mass spectrometry (GC / MS). Volatile oil analysis showed 25 components, presenting the 94.9% of the VO with hexadecanoic acid (26.1%), α-linolenic acid (17.9%), germacrene D (15.3%) and heptacosane (8.1%) as quantitatively the most abundant components. Phytochemical and cytogenetic data obtained in this work will contribute to general knowledge of this species which has been, until now, rarely studied in this area of research. Data might be useful in management of C. solstitialis, as invasive species, as well as better valorization of this wild growing medicinal plant.

Centaurea solstitialis ; genome size ; chromosome number ; rDNA and GC-rich DNA pattern ; volatile oil ; GC/MS

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