Chromosomal localization of selected SCARs converted from new RAPD, ISSR and R-ISSR markers linked to rye (Secale cereale L. ) tolerance to nutrient deprivation stress identified using bulk segregant analysis

Background: An adaptive mechanism in plant roots is initiated in the event of nitrogen and potassium deficiency, and it facilitates the active uptake of these elements in order to ensure plant growth and survival in stress conditions. Signaling and transduction of signals in response to changing nitrogen and potassium concentrations is a complex process, affected by interactions between various gene expression products, and often subjected to modifications. Results: In order to identify genotypic differences between phenotypes of two populations of recombinant inbred rye lines (153/79-1 x Ot1-3 and Ot0-6 x Ot1-3) in response to nutrition stress caused by nitrogen and potassium deficiency at the seedling stage, bulk segregant analysis was utilized. Identification of genotypic differences between and within pooled DNA samples involved 424 RAPD, 120 ISSR primers and 50 combinations of R-ISSR. Identified markers were sequenced and converted to SCAR, attributing to them unique ESTs annotations, and chromosomal ones to selected localizations. Significant relationships with the examined trait were described for nine and eight RAPD markers, four and five ISSR, one and three R-ISSR markers for population 153/79-1 x Ot1-3 and Ot0-6 x Ot1-3, respectively. Sequences identified for the rye genome were characterized by a uniqueness and a similarity to the sequence of aquaporin PIP1, a gene encoding protein related to the function of the transcription factor in plant response to iron deficiency and the putative ethylene-responsive transcription factor, cytosolic acetyl-CoA carboxylase, HvHKT1 transporter, as well as HCBT proteins. Conclusion: Identified molecular markers differentiating rye genotypes of extreme response of root system on nitrogen and potassium deficiency play a significant role in systemic plant response to stress, including stress caused by nitrogen and potassium deficiency. They may constitute a system facilitating selection, and together with the material they are described in, they may be a starting point for research on mechanisms of sensing and transduction of signal across the plant.

Discrimination of population of recombinant inbred lines of rye (Secale cereale L. ) for different responses to nitrogen-potassium stress assessed at the seedling stage under in vitro conditions

Background: Plants differ in the methods used to acquire nutrients from environments with low nutrient availability, and may change the morphology of their ‘root architecture’ to be able to take up nutrients. Results: In the present study rye response to stress caused by high and low nitrogen-potassium treatments in mature embryos cultures was described within a population consisting of one hundred and thirty eight recombinant inbred lines of rye. Characterization of the response of recombinant inbred lines (RILs) to nutrient stress was presented as the results of analyses of morphological traits, and physiological and biochemical parameters of the seedlings grown in both treatments. A wide range of variability of individual RILs to induced stress was observed in the population of recombinant inbred lines, and was presented as the difference between the means of each of the analysed traits described at high- and low-nitrogen-potassium levels. Lines were grouped using Ward's agglomerative method on the basis of differences in coleoptyle length, with the longest root length and root number used as variables. Conclusions: Recombinant inbred lines at low nitrogen-potassium treatment developed: longer, shorter, or roots of similar length in comparison with the high nitrogen-potassium treatment. Discriminant function analysis showed that the discriminant variable able to clearly differentiate recombinant inbred lines in terms of their response to nutrient stress was the trait of the longest root length.

Genetic diversity and phylogenetic relationships in the rye genus Secale L. (rye) based on Secale cereale microsatellite markers

The genetic diversity and phylogenetic relationships in the genus Secale L. (rye) was evaluated using 24 Secale cereale microsatellite (SCM) markers. The average polymorphism information content (PIC) value of each microsatellite locus in 30 Secale accessions evaluated was higher than that in 47 cultivated ryes (Secale cereale ssp. cereale). The mean genetic similarity (GS) index in Secale was lower than that in cultivated rye. The highest within-species GS index was observed for S. sylvestre and the lowest for S. strictum, whereas the highest between-species GS index was found between S. cereale and S. vavilovii and the lowest between S. sylvestre and S. cereale. There was no obvious difference in GS levels in the cultivated rye accessions from Asia, Europe, North America or South America. Cluster analysis indicated that all the Secale accessions could be distinguished by the 24 microsatellite loci. We also found that the S. sylvestre accessions were obviously divergent from the accessions of other species and that the S. vavilovii accessions were closely related to the S. cereale accessions. Our results also showed that S. strictum was heterogeneous and showed great within-species differences. The microsatellite-derived dendrogram faithfully reflected the phylogenetic relationships between Secale species but did not indicate a possible domestication process of the cultivated rye based on the geographical sources of the accessions.