Flowers Characteristics of Selected Species of Lime-Tree (Tilia spp.) in Terms of miRNA-Based Markers Activity, Mannose Expression and Biological Compounds Content

The significant healing effect of Tilia platyphyllos Scop. and Tilia cordata Mill. flowers are well known. However, the flowers of Tilia tomentosa Moench. are not suitable for harvest due to their toxic effects. To investigate the diverse background of this effect, we applied a functional miRNA-based marker, mannose expression analysis and determined the content of bioactive compounds. Out of nine tested markers, three (miR160, miR167 and miR408) provided reproducible miRNA-based loci and two of them (miR160 and miR398) enabled the acquisition of fingerprinting specific to flower and leaf samples of T. platyphyllos and T. tomentosa. The most pronounced profiling was specific for miR408 marker, the function of which is connected to plant defense and adaptation mechanisms. We confirmed the suitability of microRNA-based markers for polymorphism determination of flowers of selected species of lime-tree. The highest values of antioxidant activity, flavonoids, total polyphenols and phenolic acids content have been reached in silver linden flowers. When comparing the transcription activity of mannose in flowers, more than 30 times higher levels of mannose transcripts for the silver linden flowers was observed.