Karyotype of Mesembryanthemum crystallinum (Aizoaceae) studied by chromosome banding, FISH with rDNA probes and immunofluorescence detection of DNA methylation

Abstract

The karyotype of the common ice plant Mesembryanthemum crystallinum L. (Aizoaceae) was studied using Chromomycin A₃ (CMA)/4′,6-diamidino-2-phenylindole (DAPI) staining, fluorescence in situ hybridization with 5S and 18S–5.8S–25S rDNA probes, DAPI/C-banding and immunodetection of 5-methylcytosine. A single bright CMA-band was revealed on the satellite chromosome, whose location was coincided with a position of a site of 18S–5.8S–25S rRNA genes. A site of 5S rRNA genes was observed on one of the other chromosomes. Relatively large DAPI/C-bands were mainly localized in the pericentromeric regions of the chromosomes. DAPI/C-banding patterns allowed us to identify all the chromosomes in the karyotype of M. crystallinum. The methylation of euchromatic chromosome regions was weaker as compared with heterochromatic DAPI/C-bands, which were hypermethylated. The obtained results may provide opportunities for investigating, at the chromosomal level, the genomic changes occurring in M. crystallinum either under salinization or under the action of other stress factors.

Keywords::

• Mesembryanthemum crystallinum
• karyotype
• chromosome banding
• FISH
• DNA methylation

Additional information

Funding

This work has been supported by Russian Foundation of Basic Research (RFBR) [grant number 14-08-01167], [grant number 13-04-01770], [grant number 12-08-00131], [grant number 13-04-00636]; and by Fundamental Research Program of Presidium of the Russian Academy of Sciences (RAS) “Dynamics of Plant, Animal and Human Genofonds”.