Comparative molecular cytogenetic characterization of seven Deschampsia (Poaceae) species

Abstract

The genus Deschampsia P. Beauv (Poaceae) involves a group of widespread polymorphic species. Some of them are highly tolerant to stressful and variable environmental conditions, and D. antarctica is one of the only two vascular plants growing in Antarctic. This species is a source of useful for selection traits and a valuable model for studying an environmental stress tolerance in plants. Genome diversity and comparative chromosomal phylogeny within the genus have not been studied yet as karyotypes of most Deschampsia species are poorly investigated. We firstly conducted a comparative molecular cytogenetic analysis of D. antarctica (Antarctic Peninsula) and related species from various localities (D. cespitosa, D. danthonioides, D. elongata, D. flexuosa (= Avenella flexuosa), D. parvula and D. sukatschewii by fluorescence in situ hybridization with 45S and 5S rDNA, DAPI-banding and sequential rapid in situ hybridization with genomic DNA of D. antarctica, D. cespitosa, and D. flexuosa. Based on patterns of distribution of the examined markers, chromosomes of the studied species were identified. Within these species, common features as well as species peculiarities in their karyotypic structure and chromosomal distribution of molecular cytogenetic markers were characterized. Different chromosomal rearrangements were detected in D. antarctica, D. flexuosa, D. elongata and D. sukatschewii. In karyotypes of D. antarctica, D. cespitosa, D. elongata and D. sukatschewii, 0–3 B chromosomes possessed distinct DAPI-bands were observed. Our findings suggest that the genome evolution of the genus Deschampsia involved polyploidy and also different chromosomal rearrangements. The obtained results will help clarify the relationships within the genus Deschampsia, and can be a basis for the further genetic and biotechnological studies as well as for selection of plants tolerant to extreme habitats.

Molecular cytogenetics of valuable Arctic and sub-Arctic pasture grass species from the Aveneae/Poeae tribe complex (Poaceae)

“…14, A. aequalis, A. longiglumis, B. syzigachne and H. lanatus) and tetraploid (2n = 4x = 28, A. arundinaceus, A. latifolia and D. flexuosa) karyotypes with the typical for cereals basic chromosome number x = 7, except for the paleopolyploid D. cespitosa having 2n = 26 chromosomes. Our findings agreed with the cytological data reported earlier[36,37,62]. Particular, for D. cespitosa and some other Deschampsia species with 2n = 26, the analysis of meiotic chromosome behavior confirmed the basic number of chromosomes (n = 13) and also their diploid status[63].…”

“…Chromosome staining with DAPI performed after FISH/GISH procedures revealed DAPI-banding patterns specific to the studied species accessions. Large chromosomes, etc,) are especially common [27,37], and this karyotype diversity is considered to be related to the plasticity of plant genomes [60,61]. Despite the stressful natural environmental conditions, the cytogenetic analysis showed that the studied accessions presented normal diploid (2n [37,62,65].…”

“…Large chromosomes, etc,) are especially common [27,37], and this karyotype diversity is considered to be related to the plasticity of plant genomes [60,61]. Despite the stressful natural environmental conditions, the cytogenetic analysis showed that the studied accessions presented normal diploid (2n [37,62,65]. Their appearance in a karyotype is associated with genome instability though functional role of Bs is still not fully understood [65][66].…”

“…sukatschewii (confirming their close relationships). We have also found that D. sukatschewii genome was rich in AT-heterochromatin [37]. Besides, the species from both Deschampsia and Holcus contain common DNA repeats CON1, CON2, COM1 and COM2 which are widespread in Poaceae [15].…”

Molecular cytogenetics of valuable Arctic and sub-Arctic pasture grass species from the Aveneae/Poeae tribe complex (Poaceae)

“…Besides, the species from both Deschampsia and Holcus contain common DNA repeats CON1, CON2, COM1 and COM2 which are widespread in Poaceae [15]. parvula [37]. According to the phylogenetic analyses inferred from nuclear ITS and plastid trnL sequence data, D. flexuosa is regarded a better suited to the genus Avenella [78].…”