Cytogenetic characterization and nuclear DNA content of three North African endemic Centaurea species

• Published in: Plant biosystems 2016-05, Vol.150 (3), p.501-511
• Main Authors: Benamara-Bellagha, M., Baziz, K., Pustahija, F., Khalfallah, N., Siljak-Yakovlev, S.
• Format: Article
• Language: English
• Subjects: 5S and 35S rRNA genes; Centaurea; Fluorescent in situ hybridization; fluorochrome banding; genome size; heterochromatin; karyotype; Life Sciences
• ISSN: 1126-3504; 1724-5575
• DOI: 10.1080/11263504.2014.981234

Three endemic Centaurea species from North Africa are investigated for the first time by chromomycin fluorochrome banding for GC-rich DNA distribution, fluorescence in situ hybridization for physical mapping of rRNA genes, and flow cytometry for genome-size assessment. Investigated species belong to three different sections and possess three basic chromosome numbers: C. tougourensis subsp. tougourensis 2n = 4x = 36 (x = 9), C. musimonum 2n = 2x = 20 (x = 10), and C. maroccana 2n = 2x = 24 (x = 12). The number and distribution of chromomycin positive bands (CMA + ) and 18S-5.8S-26S (35S) rDNA loci were different among investigated species and ranged from 6 to 80 chromomycin bands and from 2 to 6 35S rDNA loci. The three species have just one 5S rDNA locus at intercalary position on a separate chromosome pairs, except in the case of C. musimonum in which both rDNA loci were localized on the same chromosome. All rDNA loci were co-localized with CMA + bands, except three 35S in C. musimonum. Genome size ranged from 2C = 1.66 to 2C = 2.86 pg in diploid species (C. musimonum and C. maroccana, respectively) and to 2C = 4.51 pg in tetraploid C. tougourensis subsp. tougourensis.