Representatives of the resurrection plants from Gesneriaceae family are included in the Red Book of Bulgaria, in the European Register of rare, endangered, and endemic plants, and are subjects of world’s conventions on the preservation of the biodiversity. The unique feature of these plants to recover from prolonged dehydration (anabiosis) is explored in numerous studies. These species are also Tertiary relics, so they could give us important knowledge about plant evolution.Our research group at the University of Plovdiv has established a national in vitro gene bank for Haberlea rhodopensis Friv. (25 localities) and Ramonda serbica Panc. (2 localities) from Bulgaria. The national gene bank is based on original and modified in vitro technologies and can serve as a conservation and biodiversity investigation center for the family Gesneriaceae.Basing on our work with Haberlea rhodopensis Friv., we are developing a strategy for conservation and investigation of rare and relic plant species (mapping and exploration of habitats – assessing the local risk of extinction - introducing in an in vitro gene bank - model plants for research – adaptation and possible re-introduction in endangered habitats). This strategy can be adapted and used for conservation and investigation of other rare, protected, relic and endemic plants from other regions of Europe and worldwide.

Among the especially interesting and rare plants on the Balkan Peninsula are tertiary relics and endemics belonging to the tropical family Gesneriaceae: Haberlea rhodopensis Friv (Rhodope silivryak, Orpheus' flower) and representatives of the genus Ramonda. Haberlea rhodopensis Friv. is included in the European list of rare, in danger of extinction and endemic plants and in the Bulgarian list of endangered plants. In recent years, our team has extended in a new directions the traditions of many years' investigations of this interesting species at the Dept. of Plant physiology and Molecular biology. We started a thorough exploration of the various habitats and ecological characteristics of Haberlea rhodopensis Friv. Simultaneously, at the Plant Biotechnology laboratory at the University of Plovdiv we started the establishment of a live collection of in vitro Haberlea rhodopensis Friv. from various populations and habitats in Bulgaria. Such in vitro live collection with the aim of conservation and investigation of the natural population is created for a first time in Bulgaria. This is accomplished through an in vitro system for regeneration and propagation, modified by our research group. The live collection of in vitro Haberlea rhodopensis Friv. plants will be a donor for conservation and reintroduction of adapted in vitro plants in their natural endangered habitats and also for physiological studies of drough tolerance, and multidisciplinary comparative analyses.

In Bulgaria, this species has not been cultivated in vitro with the aim of conservation and investigation of the natural population. For this purpose, at the Plant Biotechnology laboratory at the University of Plovdiv we started the establishment of a live collection of in vitro Ramonda serbica Panč. This is accomplished through an in vitro system for regeneration and propagation, modified by our research group. The live collection of in vitro Ramonda serbica plants will be a donor for conservation and reintroduction of adapted in vitro plants in their natural endangered habitats and also for physiological studies of drough tolerance, and multidisciplinary comparative analyses.

Long non-coding RNAs (lncRNAs) and RNA–protein complexes (RNPs) are increasingly recognized as central to the regulatory complexity of modern eukaryotes. This review proposes that the remarkable diversity of eukaryotic systems arises from the long-term integration of ancient RNA/RNP mechanisms, layered with innovations introduced by successive symbioses. We outline four interconnected levels of symbiosis contributing to this process: (1) molecular symbiosis, involving dynamic assemblies of RNAs, proteins, and membraneless organelles (MLOs); (2) genome symbiosis, driven by the expansion of non-coding and repetitive DNA; (3) intracellular symbiosis, initiated by mitochondria acquisition; and (4) intercellular symbiosis, rooted in the cellular cooperation that enables multicellularity. We highlight lncRNAs and intrinsically disordered proteins (IDPs) as versatile mediators that interweave interactions across scales, predominantly within phase-separated condensates. Building upon these multi-level processes, we propose the framework of integrated symbiotic pleiotropy—a concept where molecular components acquire layered functional roles as a direct consequence of successive symbiotic acquisitions. This paradigm unites information layering, functional moonlighting, molecular tinkering, and exaptation into a coherent trajectory for eukaryotic evolution.

Resurrection plants are incredibly tolerant to drought. When dried out, they temporarily halt photosynthesis and respiration while protecting cellular structures. Upon rehydration, they rapidly resume normal function, allowing their cells and tissues to become re-energized. Nucle-otides play a crucial role as energy and information carriers in all living organisms. However, the dynamics and functioning of these vital compounds in resurrection plants have not been exten-sively studied. Nucleotide, nucleoside, and nucleobase extraction and analysis are technically challenging, so improved methods are of continued interest, especially techniques that can dis-tinguish the nucleotides’ degree of phosphorylation. Here, we describe an accurate mass, high-resolution hydrophilic interaction chromatography (HILIC-LC-hrMS/MS)- based method for quantitative profiling of nucleotides and their phosphate forms in the resurrection plant Haberlea rhodopensis Friv. The proposed ion-pair free method, exploiting a gradient of both organic com-ponent and buffer salt concentrations, was applied on tissue samples from leaves and roots of H. rhodopensis exposed to dehydration and subsequent rehydration. In the proposed method, 20 analyses (nucleosides and nucleotides) were separated by HILIC. This preliminary study identified remarkable features in nucleotide phosphate content and dynamics during desiccation and sub-sequent rehydration suggesting alternative energy metabolism pathways in drought tolerance of resurrection plants.