Efficiency of different PCR-based marker systems for assessment of Iris pumila genetic diversity

Peer reviewe

Comparative molecular cytogenetic characterization of seven Deschampsia (Poaceae) species.

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

Chromosome spreads of <i>D</i>. <i>antarctica</i>.

<p>(A) Giemsa C-banded chromosomes of the specimen from Galindez Island. (B) Inverted image of the DAPI/C-banded karyotype and (C) localization of 45S (green) and 5S (red) rDNA sites on chromosomes of the specimen from Galindez Island. (D) Ag-NOR staining patterns (dark segments) of chromosomes of the specimen from Skua Island. (E) Localization of telomeric repeats (green), 45S (green) and 5S (red) rDNA loci and in the karyotype of the specimen from Skua Island. Arrows point to the intercalary loci of telomere repeats detected on the largest chromosome pair. (F) Distribution of 5S rDNA sites (red) and GAA microsatellite sequence (green) on chromosomes of the specimen from Skua Island. Scale bar—5 μm.</p

Chromosome spread of <i>D</i>. <i>antarctica</i> specimen from Darboux Island.

<p>Chromosome localization of 45S (green) and 5S (red) rDNA sites and inverted image of DAPI/C-banded B-chromosomes (bottom right). Arrows point to the B-chromosomes. Scale bar—5 μm.</p

Karyograms and idiograms of <i>D</i>. <i>antarctica</i> chromosomes.

<p>Karyograms after (A) Giemsa C-banding and (B) FISH with 45S (green) and 5S (red) rDNA probes (the same metaphase plate as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0138878#pone.0138878.g001" target="_blank">Fig 1A</a>). Karyograms after (C) DAPI/C-banding (inverted image) and (D) FISH with 45S (green) and 5S (red) rDNA (the same metaphase plate as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0138878#pone.0138878.g001" target="_blank">Fig 1B and 1C</a>). (E) Idiograms of <i>D</i>. <i>antarctica</i> showing relative sizes and positions of DAPI/C-bands (black segments), 45S (green) and 5S rDNA (red).</p

First record of the endophytic bacteria of Deschampsia antarctica Ė. Desv. from two distant localities of the maritime Antarctic

Abstract Endophytic bacteria, recognized for their beneficial effects on plant development and adaptation, can facilitate the survival of Antarctic plants in severe environments. Here we studied endophytes of the vascular plant Deschampsia antarctica Ė. Desv. from two distantly located regions in the maritime Antarctic: King George Island (South Shetland Islands) and Galindez Island (Argentine Islands). Bacterial group-specific PCR indicated presence of Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Firmicutes, Cytophaga-Flavobacteria and Actinobacteria in root and leaf endosphere of D. antarctica sampled at four distinct sites of both locations. The diversity of endophytic bacteria was significantly higher in the leaves compared to the roots in plants from Galindez Island. Similarly, the diversity of endophytes was higher in the leaves rather than roots of plants from the King George Island. Twelve bacterial species were isolated from roots of D. antarctica of Galindez Island (the Karpaty Ridge and the Meteo Point) and identified by sequencing the 16S rRNA gene. Isolates were dominated by the Pseudomonas genus, followed by the genera Bacillus and Micrococcus. The vast majority of the isolates exhibited cellulase and pectinase activities, however, Bacillus spp. expressed neither of them, suggesting lack of genetic flow of these traits in endophytic bacilli in the maritime Antarctic. Pseudomonas sp. IMBG305 promoted an increase in the leaf number in most of the treated plant genotypes when compared with non-inoculated plants, and a rapid vegetation period of D. antarctica cultured in vitro, albeit the length of leaves in the treated plants was significantly lower, and flavonoid content leveled off in all treated plants. D. antarctica is known to develop diverse ecotypes with regard to ecological conditions, such as organic input, moisture or wind exposition. The D. antarctica phenotype could be extended further through the endophyte colonization, since phenotypic changes were observed in the inoculated D. antarctica plants grown in vitro in our study. Herewith, endophytes can contribute to plant phenotypic plasticity, potentially beneficial for adaptation of D. antarctica